Live Test Researchers tested the Lewis robot photographer on a group of 5,000 subjects over a period of 40 hours.. During this 40 hour run, people guests at a large technology event eith
Trang 2Let your geek shine.Meet Leah Buechley, developer of LilyPad—a sew-able microcontroller—and fellow geek Leah used SparkFun products and services while she developed her LilyPad prototype
The tools are out there, from LEDs to conductive thread, tutorials to affordable PCB fabrication, and of course Leah’s LilyPad Find the resources you need to let your geek shine too.
©2008 SparkFun Electronics, Inc All rights reserved.
»Sharing Ingenuity
S P A R K F U N C O M
Trang 3Free Book
with Kit
Trang 408 Robytes by Jeff Eckert
Stimulating Robot Tidbits
12 GeerHead by David Geer
Lewis, the Robot Photographer
16 Ask Mr Roboto by Dennis Clark
Your Problems Solved Here
58 Twin Tweaks
by Bryce and Evan Woolley
There’s a New Humanoid on the Block
64 Robotics Resources
by Gordon McComb
Stocking Up with Surplus Electronics
67 Dif ferent Bits
77 Then and Now by Tom Carroll
Robotics — A Historical Perspective
PAGE 12
THE COMBAT ZONE
Trang 5Tech Zone.
by Robert Doerr
Scaling and inverting encoder values
to fit your particular application.
by Fred Eady
Learn what it takes to design, build, and code a heavy duty DC motor driver module.
— Part 2
by Alan Marconett
This final installment examines the QwikFlash controller board and the software that runs Loki.
SERVO Magazine (ISSN 1546-0592/CDN Pub Agree#40702530) is published
monthly for $24.95 per year by T & L Publications, Inc., 430 Princeland Court, Corona,
CA 92879 PERIODICALS POSTAGE PAID AT CORONA, CA AND AT
ADDITION-AL ENTRY MAILING OFFICES POSTMASTER: Send address changes to SERVO
Magazine, P.O Box 15277, North Hollywood, CA 91615 or Station
A, P.O Box 54,Windsor ON N9A 6J5; cpcreturns@servomagazine.com
PAGE 44
PAGE 39 PAGE 34
Features & Projects
Trang 6Published Monthly By
T & L Publications, Inc.
430 Princeland Court Corona, CA 92879-1300
(951) 371-8497
FAX (951) 371-3052 Webstore Only 1-800-783-4624
www.servomagazine.com
Subscriptions
Toll Free 1-877-525-2539 Outside US 1-818-487-4545
P.O Box 15277 North Hollywood, CA 91615
PUBLISHER
Larry Lemieux
publisher@servomagazine.com ASSOCIATE PUBLISHER/
Jeff Eckert Tom Carroll Gordon McComb David Geer Dennis Clark R Steven Rainwater Fred Eady Kevin Berry Robert Doerr Ted Larson Alan Marconett Kym Graner Bryce Woolley Evan Woolley Heather Dewey-Hagborg Nick Martin Mike Jeffries Bryan Ruddy
CIRCULATION DIRECTOR
Tracy Kerley
subscribe@servomagazine.com MARKETING COORDINATOR
WEBSTORE
Brian Kirkpatrick
sales@servomagazine.com WEB CONTENT
Michael Kaudze
website@servomagazine.com PRODUCTION/GRAPHICS
Shannon Lemieux Joe Keungmanivong
ADMINISTRATIVE ASSISTANT
Debbie Stauffacher
Copyright 2008 by
T & L Publications, Inc.
All Rights Reserved
All advertising is subject to publisher’s approval.
We are not responsible for mistakes, misprints,
or typographical errors SERVO Magazine
assumes no responsibility for the availability or condition of advertised items or for the honesty
of the advertiser.The publisher makes no claims
for the legality of any item advertised in SERVO.
This is the sole responsibility of the advertiser Advertisers and their agencies agree to indemnify and protect the publisher from any and all claims, action, or expense arising from
advertising placed in SERVO Please send all
editorial correspondence, UPS, overnight mail,
and artwork to: 430 Princeland Court,
Small is Big
When it comes to robot
components, small is big If you’ve
followed the robotics news lately, you
know that academic and military
R&D communities are busy at work
developing robots that mimic – in
form and function – small crawling
and flying insects Need to locate
survivors in the rubble of a collapsed
building? Simply release a swarm of
heat-seeking crawling robots that can
squeeze through cracks without
disrupting the rubble and
endangering trapped victims Need
an up-close view of a hostage
situation? A swarm of flying
microbots with photosensors could
provide police with a composite,
real-time image of the victims and
their captors
Despite ongoing advances in
research laboratories, there are
numerous challenges that must be
overcome before practical
autonomous insect swarms can
become a reality There are issues
of how to provide communicationsbetween each insect-sized robot andtheir human masters, local
computation, sensors, power, and
of course, powerful, lightweight,controllable micromotors And there’sthe underlying issue of cost
A recent advance in the area
of micromotors has been thecommercial availability of linearmicromotors from New Scale
Technologies (www.newscaletech.
com) Their series of Squiggle motors
fills the void between the microscopicnanomotors and the miniature servosand electronic/pneumatic linearactuators popular among roboticsenthusiasts
I had the opportunity to evaluateNew Scale’s mid-sized offering — theSquiggle SQL-1.8-6 linear motor —shown in the photo As the namesuggests, the motor is a mere 1.8
mm in width The rectangular motorbody is 6 mm long, with a 12 mmaxial screw running through itscenter The 160 milligram SQL 1.8 iscapable of handling a 30 g loadwhen driven by a 400 mW, 40V, 171kHz pulse The even smaller SQL 1.5linear motor can work with a 20 gload As illustrated in the photo, theelectrical connection to the Squigglemotor is via a flex printed circuitstrip
With a PC-based controlapplication and USB-to-Squiggleinterface, I was able to vary the travelrate from micrometers per second tomillimeters per second, with animpressive 0.5 micrometer resolution
Although the relatively fragile motorwas glued to a polycarbonate mount
Mind / Iron
by Bryan Bergeron, Editor
Mind/Iron Continued
Piezoelectric Squiggle micro motor on
polycarbonate mount shown next to a
six-pin DIP for size comparison.
Trang 7for evaluation purposes, I could easily envision a
spider-sized eight-legged walker, powered by 16
skeleton-mounted Squiggles
The size of the peripherals that accompanied the
motor — a wall wart power supply, a USB driver card, and
a three-foot USB cable — not to mention the desktop PC
and software — explains why the robotics shops aren’t
offering autonomous robots sporting Squiggle-based
grippers and actuators Even a six-pin DIP dwarfs the
Squiggle, much less a PIC or BASIC Stamp However, the
control issue should be partially solved by the time you
read this New Scale has a miniature ASIC driver under
development that could form the heart of a Squiggle
spider robot
Power issue is another matter The smallest battery
packs that I’ve used are thin-film lithium-polymer cells
designed for miniature indoor R/C aircraft The thin,
dime-sized cells power a single-motor aircraft for about
five minutes As such, an autonomous eight-legged
Squiggle spider would likely have a lifespan measured
in seconds with current battery technology Even so,
in some applications, 20-30 seconds of operation
could be worth the cost of a swarm of insect-sized
microbots
On the topic of microsensors, with the exception of
Hall-effect devices, I haven’t seen any commercial sensor
offerings that come close to the level of miniaturization
required for an insect-sized microbot I’d like to have an
affordable ultrasonic or IR rangefinder comparable in
relative size to the Squiggle However, consider the
challenge in creating a suitable IR rangefinder withstandard components A typical IR LED alone is about thesize of an insect’s head And the available ultrasoundrangefinders require even more volume Clearly, when itcomes to microsensors for autonomous microbots, it’s timefor a new generation of SMT devices
Although autonomous microbots made completely ofcommodity — read affordable and readily available —components may be a few years away, there are myriadapplications of micromotors in other areas of robotics Themost obvious applications range from the manipulation ofcamera optics and R/C mini helicopter control surfaces, tocontrol of microvalves in implantable drug delivery devices
to surgical robots Although I expect to see the first large-scale applications of micromotors in the consumerelectronics industry, the medical applications will likely have the most profound effect on quality of life
Consider that current surgical robotics rely onstandard-sized motors connected to scalpels and otherinstruments through cables Although these roboticsystems enable surgeons to operate with greater efficiencyand effectiveness than traditional methods, because of thephysical arrangement of cables and instruments, theworking area is constrained to only a few inches across.The use of micromotors connected directly to instrumentswould allow for a much larger work area for tele-surgeons,
as well as lighter, mechanically simpler surgical robots Sizeand weight can be critical factors if the remote patienthappens to be an astronaut on Mars, or a critically injured
US soldier in a remote area of the world SV
Dear SERVO:
The “analog” servo block diagram, Figure 5, of theServo Buddy article in May 2008, is missing the velocityfeedback path from the motor to the local pulsegenerator Without this damping feedback, the servo willoscillate After the stretched drive pulse has ended, themotor back EMF is used to modify the next local pulse
In servos that use the NE544 IC, this feedback is from pin 9 to pin 1 via a resistor For the NJM2611 IC, frompin 11 to pin 15
It is interesting to note that years ago what isnow called an analog servo was called a digital servo.Back then, an analog servo required an analog VOLTAGEinput
— William J Kuhnle
RESPONSE: While I tried to keep the diagram simple,
it might have been good to include that Thanks for pointing it out.
— Jim Stewart
SchmartBoard Is Looking for
Beta Testers
New Website will be Social Network
for Electronics Enthusiasts
SchmartBoard is looking for people to beta-test a soon
to be opened web space call Solder By Numbers™
The website, which is due to launch in late summer,
will be a social network for electronics enthusiasts
SchmartBoard is looking for all levels of testers from
professional engineers to novices who have an interest
in electronics They are looking for people from around
the world
According to SchmartBoard’s VP of Sales &
Marketing, Neal Greenberg, “SchmartBoard is not yet
ready to reveal specific details about the website,
except that it is web 2.0 for electronics enthusiasts
Solderbynumbers.com will be a place to design and
build your electronic circuits while you create a worldwide
network of peers The site will be much more than a
social network It will be a place to collaborate, create,
communicate, and learn.”
To sign up to be a beta-tester, go to www.solder
bynumbers.com.
Trang 8The Vulture Seldom Comes
Home to Roost
On a more celestial level, DARPA
is also funding a competition to
develop an unmanned aerial vehicle
that will shatter endurance records
The bird will draw 5 kW of power,
carry a 1,000 lb (450 kg) payload,
stay aloft for at least five years, and
remain in its assigned airspace 99
percent of the time while fighting
winds encountered at operating
altitudes, reportedly ranging from
60,000 to 90,000 ft (18,000 to
27,000 m) The goal is to provide
long-term intelligence, surveillance,
reconnaissance, and communication
missions over locations of interest
Contractors for phase one are
Aurora Flight Sciences (www.aurora.
aero), Boeing (www.boeing.com),
and Lockheed Martin (www.lock
heedmartin.com) A variety of
propulsion approaches — including
solar and internal combustion — will
be considered; however, nuclear and
lighter-than-air designs have been
ruled out The winning design must
comply with space — not aviation —
industry standards, because only a
“pseudo-satellite” will handle the
demanding requirements A
supervi-sory engineer at NASA observed,
“What you don’t want to build is afragile, expensive pain in the butt.”
The Aurora offering will be based
on its “Odysseus”
design, which uses solarpower during daylighthours and stored energy
at night It combinesthree “constituent aircraft” in a 500 ft(150 m), intriguing Z-wing configuration
Boeing is expected tofield a design based onthe existing British-builtZephyr high-altitude,long-endurance UAV,from partner QinetiQ
(www.qinetiq.com).
Lockheed Martin is stillmum on the subject
The competitors have 12 months
to come up with their initial designsfor DARPA review Phase two will endwith a three-month flight test of asubscale demonstrator, and the finalphase will require a 12-month test of
a full-scale vehicle
Mini Network Bots
Also pulling down governmentfunding — in this case, up to $3
million over three years from theDefense Advanced Research Projects
Agency (www.darpa.gov) — is iRobot (www.irobot.com) Under
the grant, the company will developthe LANdroid robot, a portable com-munications relay device According
to the contractor, “This robot will besmall enough that a single dismountedwarfighter can carry multiple robots,inexpensive to the point of being disposable, robust enough to allowthe warfighter to drop and throwthem into position, and smart enough
to autonomously detect and avoidobstacles while navigating in theurban environment.”
The objective is to enable networking in urban areas wherebuildings and other pesky objects can block wireless operations Inoperation, each of the little guys willwander around until it finds a goodspot to function as a node and thenjoin the rest of the swarm to form the network If one is destroyed, theothers will adjust their positions tokeep the system up and running
New Touch Technology
One of the perennial problems inrobotics is improving the machine’s
Aurora’s Odysseus design: A possible configuration of the Vulture UAV.
Photo courtesy of Aurora Flight Sciences.
Sneak peak at what the LANdroid robot will look like Photo courtesy of DARPA.
by Jeff Eckert
Trang 9sense of touch, and what could be a
better way to solve it than to learn
from our touchy-feely friend, the rat?
Enter BIOTACT (BIOmimetic Technology
for vibrissal ACtive Touch, www.
biotact.org), a project funded by the
European Union and involving nine
research groups in seven countries
The goal is to emulate how such
mammals as rats and Etruscan shrews
can rapidly sweep their whiskers
back and forth to gather information
about their surroundings Thus, a bot
fitted with hundreds of whisker-like
sensors may be able to seek, identify,
and track fast-moving target objects,
even in poorly lit places where machine
vision doesn’t get you anywhere
The challenge is to develop new
biomimetic computational methods
and technologies that enable the
technology But the consortium
has been granted four years and
$11.6 million to do it, so the odds
look good
Showcase of Robotenders
It’s beginning to look like the
Germanic tribes have a curious
fetish about linking robotics with
such ostensibly unrelated fields as
sociology, philosophy, and art (see
last month’s Robytes) In this vein, the
upcoming 10th anniversary of the
RoboExotica conference recently
came to light According to the
event’s Vienna-based
creator (www.robo exotica.com), “Until
recently, no attemptshad been made topublicly discuss therole of cocktail robotics as an indexfor the integration
of technological innovations into thehuman Lebenswelt[environment], or
to document theincreasing occurrence of radical hedonism in man-machine communication.” Imagine that
But you can stop worrying, because
“RoboExotica is an attempt to fill this vacuum.”
RoboExotica generally consists
of a series of events (exhibition, conference, workshops, music, andfilm presentations) held at variouslocations in Vienna But this year,sometime after the December 4thkickoff in Austria, it will be presented
in San Francisco, as well, “thus
facilitating the already existingexchange of ideas between the WestCoast’s very much alive technology/art scene and the RoboExotica mother ship in Vienna.”
Unfortunately, the US incarnationwill not include the annual cocktailrobot awards, where you can enter amachine in one of five categories:serving cocktails, mixing cocktails,bartending conversation, smoking culture, and other achievements inthe sector of cocktail culture To participate, you’ll have to show up atthe Rote Bar/Volkstheater Wien
(www.volkstheater.at/rotebar html) The program is still under
development, so check the websitefrom time to time for details
Bot Assists Endoscopy
This month’s device for tauntingthe squeamish is EndoAssist, a roboticendoscope manipulator offered byProsurgics Ltd Used in invasivethoracic and abdominal surgery, it isparticularly useful for ardiothoracic,urological, bariatric, ob/gyn, andgeneral surgery Perhaps the mostinteresting feature is that the surgeoncontrols camera angles simply bymoving his head Glance left, and thecamera moves left, and so on You
R o b y t e s
Artist’s concept of the “ScratchBot”
employing the BIOTACT sensor.
Photo courtesy of the BIOTACT project.
The EndoAssist robotic manipulator Photo courtesy of Prosurgics.
A contestant from RoboExotica 2007.
Photo courtesy of Roboexotica.com.
Trang 10can also pan, zoom, or modify the
view in any direction For a video
demonstration that may affect your
ability to keep lunch down, visit
www.prosurgics.com/prosurgics_
endoassist.htm.
Uribot Tends Kobe Airport
Finally, the strangest application
of robotics of late would be Dasubee,
a bot designed specifically to clean
urinals One is already operating in
the Kobe, Japan airport An astute
observer will note that it resembles
an elephant Designer Susumu Kanai
revealed that this design was inspired
by the pachyderm’s trunk, which
resembles the powerful water cannon
employed by the bot The ears are
handles, the eyes are the start and
stop buttons, and its little yellow hat
is the filler cap for the 13 gal (50 l)
tank Reportedly, usingspecially developedantibacterial detergent,Dasubee can shine up
a fouled privy in only
10 seconds
If you’re stillreluctant to buy one,consider that Kanaihas included “avacuum function tobreathe in a scraperand the water of thefloor to be able towash the dirt scattered
to the floor together
on the function side.”
(Something may havebeen lost in thetranslation.) You canpick one up for onlyone million yen (about
$9,500) SV
R o b y t e s
Dasubee, the urinal bot and its proud operator Photo courtesy of Impress Watch Corp.
Perform proportional speed, direction, and steering with
only two Radio/Control channels for vehicles using twoseparate brush-type electric motors mounted right and leftwith our mixing RDFR dual speed control Used in manysuccessful competitive robots Single joystick operation: upgoes straight ahead, down is reverse Pure right or left twirlsvehicle as motors turn opposite directions In between stickpositions completely proportional Plugs in like a servo toyour Futaba, JR, Hitec, or similar radio Compatible with gyrosteering stabilization Various volt and amp sizes available.The RDFR47E 55V 75A per motor unit pictured above.www.vantec.com
STEER WINNING ROBOTS
WITHOUT SERVOS!
Order at (888) 929-5055
Trang 12When Lewis the Robot
Photographer first enters acrowded room, it gets atten-tion But, once people have adjusted
to its roaming around, looking hereand there, they forget all about it
After all, it’s just a machine, anotherobject in their environment
Lewis’ ability to blend in keeps
it from creating the kind of apprehension that comes with a live photographer who roams aroundsnapping candid pictures of people (as a wedding photographer might
do, for example)
Because Lewis captures people atease, it can take a much higher quality
of photos — no blinking, phony smiles,
or stiff or awkward poses BecauseLewis recognizes faces and quicklysnaps only the best photos, it takesmany more quality pictures in thesame period at gatherings, functions,and on special occasions
Looking for Faces
Lewis starts by scanning the roomfor pairs of what appear to be legs
This way, he can identify people andthen look up to find and identify their faces Then, Lewis uses face-recognition technology that identifiesparts of images with lots of skin tonesgrouped closely together
Lewis separates real faces fromthings that may look like faces to therobot eye Lewis eliminates anythingthat is too big, too low, or the wrongshape Anything left is assumed to
be a face
Lewis can take front-on and sideangle pictures of people It continuallyscans images for the criteria that predict a face or group of faces Once
it has detected a suitable image, itadjusts the camera to take a qualityphoto, moving it into position via
a series of zooming, tilting, and panning
The robot uses object avoidancetechnology to guide itself aroundobjects and people, and maintains itsposition within the mass of subjects
by recognizing a given object and centering itself in the group based onthe position of that object
Forming Pictures
How does Lewis form pictures offaces? By following rules One suchrule is the rule of thirds The rule ofthirds says that if you split a pictureinto thirds, first horizontally, then alsovertically, the primary point of visualinterest in the photo should be wherethe lines cross Lewis makes humanfaces the points of greatest interest,placing them at these cross points
Contact the author at geercom@alltel.net
by David Geer
Lewis, the Robot Photographer
At first brush, a robot that snaps people’s pictures might not imbue the mind with
a novel image But, a photographer that sets its subjects at ease, circumvents their shy and self-conscious natures and related facial reactions, and captures the essence
of the subject unawares, now that’s a wonder to see!
Full side view of Lewis.
Trang 13Photographers try to avoid empty
space in their photos This helps
ensure that photos contain as much
relevant visual information as possible
Lewis weighs the rule of thirds and
the rule around empty space one
against the other whenever they
conflict, to take the best pictures
Lewis can also think for himself
when taking photos He is free to
break the rules altogether and take
feedback about his images He uses
this information to learn which rules
to break and when in order to deliver
great photos based on a sort of
photographic instinct
Live Test
Researchers tested the Lewis
robot photographer on a group of
5,000 subjects over a period of 40
hours Lewis took 3,000 pictures in
that period During this 40 hour run,
people (guests at a large technology
event) either ignored the robot
completely or tried to interact with it
Because the robot wasn’t instilled
with the ability to interact, people
quickly dispensed with it and began
socializing with other people in
the crowd Because people ignored
the robot, they relaxed and acted
naturally, enabling the robot to take
candid, natural pictures
Results
Among other things, researchers
determined that the robot should
have a sort of bi-modal capability If
someone is trying to interact with it,
it should stop what it is doing and
interact with those people, taking
their pictures where possible If no
one is trying to interact with the
robot, it should blend into the
background and continue to take
candid shots This version of the robot
is only capable of blending in So, the
robot will ignore people who want to
interact with it or who specifically look
to have their picture taken
People will be more likely to
interact with the robot on some level
if they know what it is up to What’s
it there for? In this version
of the robot it made a noise,sounding an alarm or signalwhen it had taken a picture However,the sound wasn’t loud enough formost people to hear
If the signal were louder, thiswould communicate to people in therobot’s proximity that it had just taken
a picture This would form some level
of communication between the robotand those people, and provide somesimple basis for interaction
The robot had no way of tellingpeople to hold still or say cheese Ittook four seconds for the robot to line
up shots, in which time people might
hold still to get their picture taken, orthey might move around After therobot’s test run, people suggestedthat the robot actually say cheese orshow a picture of a “birdie” (as in,look at the birdie) to signal that it wasabout to take a picture
People waiting in front of therobot hoping to have their picturestaken were often disappointed whenthe robot was navigating, getting itsbearings, or homing in on a landmarkinstead of taking pictures at that particular moment However, the
Sharing a more whimsical moment with Lewis are members of the Media and Machines Lab (from left):
Assistant Professor William Smart; Assistant Professor Cindy Grimm (seated): two of the lab’s founders, Shannon Lieberg, Engineering Class of ‘04 and research assistant Michael Dixon, B.S./M.A ‘03; and Nik Melchior, a fifth year B.S./M.S.
student in computer science and engineering Members are showing off the “playful props”
used by Lewis in the lab.
Lewis close-up head shot with camera Lewis has worked
photographing at a real live wedding reception.
GEERHEAD
Trang 14robot was programmed to take
frequent pictures of human faces even
when it may not have had the
opportunity to focus in for a good
picture To better interact with
subjects, the robot should have the
ability to communicate which mode or
“state” it is in to the subjects So, if
the robot is available to interact, it can
communicate that, and so on
Photographic subjects expectedthe robot to respond when waved at,like a human being would However,the robot didn’t have this capacityeither When the robot did seem toreact — because it turned towardsomeone by sheer coincidence whensomeone had waved at it, for example
— people thought this meant it wasmore intelligent than it actually was
In particular, when the camerapointed in their direction coinci-dentally in response to trying tohail the robot, this was mistakenfor eye contact
Lewis seemed intelligent topeople when he did whatappeared to be a double take.Because the robot face detectioncode was not optimized, the cam-era panned past the faces andbeyond by the time the softwaredetermined it had detected aface The camera then returned tofocus on the face for the picture.This apparent “double take”humanized the robot in the eyes
of on-lookers, attracting people tointeract with the robot
Likewise, other robot behaviors made the robot appearnot so smart, even though thesebehaviors were quite intelligentfor a robot in what they
accomplished One such behavior was looking at the wall (pointing itscamera toward the wall) or movingalong a wall in order to aid in its navigation While the robot was trying to get its bearings, it appearednot to “see” anyone around it, and solooked dumb
Conclusion
Continued research based onLewis should address whether Lewistruly functions in two separate modes,whether the level of sophistication ofthe people interacting with Lewis has
an impact, and whether the robot orthe people around it should drive itsinteraction SV
Lewis, the Robot Photographer
www.cs.wustl.edu/MediaAnd Machines/Lewis
The Media and Machines Lab
Full frontal view of Lewis.
Here, Nik Melchior (left), a fifth year B.S./M.S.
student in computer science and engineering,
helps create the programming framework that
allows others to command Lewis Shannon Lieberg
(center) of the Engineering class of ‘04, works Lewis’
controls with Assistant Professor Bill Smart.
GEERHEAD
Trang 15New breed of robots could soon
wander Antarctica
By GREG BLUESTEIN, Associated Press Writer
Robotic rovers have patrolled deep space and the deepest seas,
but scientists are still struggling to create drones that can
overcome the multiple challenges of exploring Antarctica.
Georgia Tech researchers think the SnoMote — a small robot
designed like a snowmobile — will be able to deal with the nasty
weather and with slippery terrain that constantly cracks and
shifts They envision dozens of SnoMotes roving Antarctica's
vast expanses to add to data already collected by satellites
and a handful of weather stations and sensors Ayanna
Howard, an associate professor at Georgia Tech in Atlanta,
has worked for two years under a NASA grant to perfect the
two-foot-long robots.
Her initial designs with spider-like legs proved too
cumbersome to navigate snowbanks So, she and her colleagues
leaned on others' designs, outfitting a snowmobile designed for
kids with sensors, gauges, and cameras, and then programming it.
She developed a program that lets the SnoMotes negotiate with each other and “bid” on which site to investigate, allowing them to decide for themselves how to dole out their assignments The next challenge, though, was to come up with navigation for the rovers Other probes tend to use distinguishing characteristics like rocks to chart their paths But such features can be hard to come by in vast icy expanses.
On a field trip to a Colorado glacier, Howard's team discovered they could use microscopic fissures in the ice and snowbanks to guide their way.
“If you can come up with a way to classify these uniquely, you can come up with a way to navigate,” she said.
Simulations so far have proved her team's formula effective, but plenty of challenges await when the robot is put to the test
on the glaciers of Alaska.
With Penn State University researcher Derrick Lampkin, Howard has designed a shell that weighs 60 to 70 pounds, can withstand harsh winters, and eventually could include heaters to keep computers and wiring running in the cold.
Lampkin said his goal is to develop a "scale-adaptable, autonomous, mobile climate-monitoring network."
The researchers hope the robots will ultimately cost around
$10,000, relatively cheap for governments, researchers, and others seeking to document changing conditions in the world's most remote places.
The more the better: Howard said in order for scientists to say with certainty how climate change is affecting the ice, they need plenty of accurate data points to create climate models She envisions a field of 40 to 50 of the SnoMotes wandering icy plains, a small army gathering data to shed light on global warming and other quandaries without breaking the bank.
“The whole concept is: How do you do this in the most affordable way?” she said.
3DLQH6WUHHW_3RZD\_&DOLIRUQLD_ _ _ZZZKLWHFUFGFRP
>_j[Y Ej^[h8hWdZ
.EW
+65 6*
6SHHG VHF 7RUTXH R]LQ 6WHHO*HDUV
+65 6*
6SHHG VHF 7RUTXH R]LQ 6WHHO*HDUV
+65 7*
6SHHG VHF 7RUTXH R]LQ 7LWDQLXP
$//63(&,),&$7,216$792/76
The Mechanicrawl • Saturday, July 12, 2008
Spend a summer day exploring the mechanical marvels along
San Francisco's North Shore! See giant running steam engines, turn
of the century automata, mechanical computers, an eight foot high
mechanical planetarium, and more You'll be able to map your own
route for the event and spend as much time at each location as you'd
like You can walk, bicycle, or use public transport for Mechanicrawl;
maps, routes, and additional info are listed under Map Your Crawl on
the website For all the details, go to www.mchanicrawl.com.
Trang 16Q.Every once in a while there is a question floated
around in my local robotics group that (I think) is
such an epiphany (read: slap forehead) that I think
it deserves a wider audience This first question is one of
this nature:
Does anyone have any recommendations for an
inexpensive DC-DC converter that has 11-14 VDC in, 5 VDC
out (up to 3-5 amps)? I need a heftier supply for the
low-level control system on my robot Currently, I’ve got a 12V,
12 Ah lead-acid battery with a 5V-1A converter, and I’m
reaching the limit of the converter when I add my sonars
and IRs later, I would prefer an off-the-shelf solution
— Daniel Herrington
A.My first thought was the TI PT78ST105, which is a
1.5 amp 5V switching regulator that works with up to
38V This nifty part has the same pin-out as the
venerable 7805 regulator and is way more efficient.
Another suggestion was the TI PTN78020 which has similar
input voltage maximums and a 6 amp output with high
efficiency since it too is a switching DC/DC converter
However, this part has lots more pins; it still needs no
external components These parts are easily found at places
like Mouser, pricing depends upon various options As good
though, as these solutions are, they are not “off-the-shelf”
and would need a circuit board to use Don Clay put forward the solution of using a BEC that the R/C airplanehobby crowd commonly uses on electric aircraft that uselarge battery voltages This is a very cool idea because itcan be connected to the robot’s main battery and will efficiently give the needed 5V in a small, self-containedunit, and it already has easily usable cabling The one thatDaniel selected was the Castle Creations CC BEC which sells
for about $22 at good ol’ HobbyTown USA (www.hobby town.com); see Figure 1 This device is very useful because
it can be set to output voltages from 4.8V to 9V by usingthe Castle USB link adapter (not included) In case you werewondering, BEC stands for Battery Eliminator Circuit In the
“old days,” electric R/C cars had a battery for the motor andanother for the R/C electronics The BEC “eliminated” one
of those batteries
Q.I want to send commands to my robot using an
IR remote I don’t want to build another IR remote;
I want to use one of the bazillions that I have lyingaround the house How do I use these? How can I decodetheir output?
— George S.
A.Oh boy, I feel a marathon answer
coming up! I’m not going to go intohuge detail about every kind of IRremote out there — there are a ton of webpages that you can Google and find thosekinds of details I’ll provide a selection ofthem at the end of this answer for those curious though I did not find a lot of pagesthat connected the dots between the variousformats and how to write a program to readthem, either So, in this answer I’ll provide thenitty gritty details of how the most popular IRcodes are created and provide some PIC codethat allows you to decode them First, theugly details there are many, MANY different
Tap into the sum of all human knowledge and get your questions answered here! From software algorithms to material selection, Mr Roboto strives to meet you where you are — and what more would you expect from a complex service droid?
Trang 17IR encoding schemes out there Wikipedia tells us that there
are literally hundreds of IR protocols! Fortunately for us, there
are three that are by far the most common: SONY SIRC,
NEC, and Phillips RC-5 If you pick up any odd remote at
your house, it will most likely be using the SONY or NEC
formats Let’s discuss each of the “big three.”
SONY SIRC Format
First off, here are a couple of links that discuss this
format There is a lot of useful information in these; I
disagree with a few things that they say (more on that later),
but since some of the data that I used to write my code
came from these links, most of what they say is accurate:
www.hifi-remote.com/infrared/IR-PWM.shtml
This site gives a lot of information on how to read the
universal IR remote entries that you use to program your
universal remotes The author calls this “PWM,” or pulse
width modulation It is more accurately called “PPM,” or pulse
position modulation, rather like R/C radio communications and
what we deal with when controlling hobby servos
www.edcheung.com/automa/sircs.htm
This site gives some hints on how to write code to send
IR signals Not what I was looking for, but you might be
interested in this if you wanted to have a robot wander into
your TV room and take over control of the TV set!
The SONY format has three timing values that we are
interested in, shown in Table 1 The Lead In is the header
before the data that tells us that the code is coming
Everyone says this is to set up the AGC (automatic gain
control) in the receiver, but quite frankly, if it didn’t look
different from the rest of the transmission how could we
tell that a new command was coming? The rest of the data
is an asynchronous data stream of 1s and 0s like the serial
data in RS-232, but coming in over modulated IR radiation
instead of a pair of wires When I say “On,” I mean that the
IR carrier is detected An “Off” means that there is no IR
detected by the sensor
The actual SONY IR command can come in three
variations: 12 bits, 15 bits, and 20 bits In every variation,
we first have the Lead In header, then we have a seven-bit
command Next, in the 12-bit protocol we have a five-bit
Device ID The Device ID tells us what is being controlled,
for instance, a TV or a DVD In the 15-bit format, the
Device Code is eight bits; in the
20-bit code, we have a five-bit
Device ID and then an eight-bit
Extended Command byte All
of my remotes were either
12-bit or 15-bit All of the
codes come in LSB first This
means that the Least
Significant Bit is first and the Most Significant Bit (MSB) islast The packet format includes some kind of a Lead Out aswell, but it is really just a guarantee of some time spacingbefore the next packet is sent Don’t bother to look for itsince its length depends upon the data just sent; it doesn’tseem to be consistent (see Packet 1)
When you code for this protocol, you need to remember to assemble the bytes by putting the bits inreverse order! Remember, they are LSB first
When you press a button on a SONY remote, it willsimply repeat the command packet every 45 ms for as long
as you hold the button Some buttons on my remoteswould only send a command once when you let up off ofthe button, but the rest just kept repeating endlessly
The NEC format is a bit different It includes some errorchecking and has a different way of dealing with repeatingpackets The NEC protocol sends a Lead In, 32 bits of data,and a Lead Out Since we can count on the Lead In and 32bits of data, don’t bother to look for the Lead Out hereeither The NEC format sends its data LSB first like SONY,
[Lead In] [0 | 1 | 2 | 3 | 4 | 5 | 6| 7] [0 | 1 | 2 | 3 | 4 | 5 | 6| 7] [0 | 1 | 2 | 3 | 4 | 5 | 6| 7] [0 | 1 | 2 | 3 | 4 | 5 | 6| 7] [Lead Out]
12 Bit Code [Lead In] [0 | 1 | 2 | 3 | 4 | 5 | 6] [0 | 1 | 2 | 3 | 4]
Command Device ID
15 Bit Code [Lead In] [ 0 | 1 | 2 | 3 | 4 | 5 | 6] [0 | 1 | 2 | 3 | 4 | 5 | 6 | 7]
20 Bit Code [Lead In] [0 | 1 | 2 | 3 | 4 | 5 | 6] [0 | 1 | 2 | 3 | 4] [0 | 1 | 2 | 3 | 4 | 5 | 6 | 7]
Command Device ID Extended Command
Description ON Time OFF Time
Lead In 2.4 ms 0.6 ms Logic 1 1.2 ms 0.6 ms Logic 0 0.6 ms 0.6 ms
Table 1 SONY timing values.
Description ON Time OFF Time
Lead In 9 ms 4.5 ms Logic 1 0.56 ms 1.68 ms Logic 0 0.56 ms 0.56 ms Repeat 9 ms 2.25 ms
Table 2 NEC timing values.
PACKET 1
PACKET 2
Trang 18but there the similarity ends The packet format looks like
that in Packet 2 By ~Device ID and ~Command, I mean
that it is inverted, or 1’s complement of its respective
Device ID and Command To check for a proper reception,
all you need to do is AND the byte with its respective
complement; if it comes up all zeros, then you have a good
reception When you hold down a button on the NEC
remote, it does not send out the same command over and
over; it sends out a special signal called the Repeat Code
The NEC protocol has four timing values that we care
about, and one we don’t (the Lead Out) Table 2 shows the
ones that we pay attention to
Phillips RC-5 Format
Some useful information on the Phillips RC-5 format
can be found here:
a logic ‘0’ and vice-versa is shown by a change in the bitphase If you are like most of us, your eyes just glazed over
at that description This is one time that a picture is prettymuch needed to explain what I mean (see Figure 2).Note that it isn’t the timing that shows what the bit is,but rather the phase of the timing But how — you ask — doyou know what a ‘1’ is and what a ‘0’ is? You know becausethe bit stream of RC-5 starts out with two 1 bits and then atoggle bit, which on the first press of the button is a 0 Figure
3 shows how a transmission is formatted An RC-5 packetconsists of the preamble of 1 1 0, then a five-bit address andthen a six-bit control RC-5 packets are encoded with the MSB(Most Significant Bit) first Because you know that the firstbit is a 1, then any bit transition from that point onwardyou can track to know what the current bit is — a 1 or a 0.Figure 3 may look a little odd because I put both sameand switch phases in every bit cell except for the start bits.Just to make it more confusing though, I’ve read that thestart bits can be either 1 1 or 1 0 I hope not; it’d make ithard to figure out the 1 startup The RC-5 protocol willrepeat the button press every 113.8 ms, but every packetafter the first one will have the Toggle bit toggled differently than the last start bit
How to Decode IR Transmissions
Okay, now that the explanations are over with, how
Figure 2 Bi-Phase encoding.
Figure 3 RC-5 packet.
Figure 4 IR detector schematic.
Part Description
C1 110 μF 25V capacitor C2-C4 1 μF 25V capacitor R1 10K 1/4W 5%
R2 2.2K 1/4W 5%
R3 1K 1/4W 5%
D1 Green LED S1 N.O button U1 PIC16F688 DIP U2 7805 regulator U3 PNA4602 IR demodulator J1 Power connector J2 Four-pin male 1” connector J3 RJ-11 six-pin connector
Table 3 IR detector parts list.
Trang 19can we use the IR transmissions from our remotes in our
robots? To see what is going on, I built a special IR
decoder board that has a Panasonic PNA4602 (38 kHz) IR
demodulator, a PIC16F688, a power plug, regulator,
programming header (Microchip ICD2 six-pin type) and a
plug for the Acroname RS-232 converter board Figure 4
shows the schematic and Figure 5 is a photo of the finished
board with everything plugged in This board was wired
together with a bunch of wire that I had lying around, so it
isn’t very sensitive to how you put it together I just wanted
an experimenter board that would show me the IR
codes and allow me to experiment with decoding the IR
transmissions Different remotes use different modulation
frequencies, but the Sharp PNA4602 will work with
frequencies between 36 kHz and 40 kHz just fine I chose
the PIC16F688 because it had an interrupt line, a hardware
USART, two timers, and an internal RC oscillator that runs
at 8 MHz, all in a 14-pin package These were all of the
hardware interfaces that I needed Unfortunately, for some
reason Microchip requires some kind of dongle to debug
this chip which I didn’t have, so I debugged using “printf”
statements in the code
The board isn’t particularly sensitive to the components
that you can use My previous list just came from my parts
bins The power connector was a barrel socket that fit the
various wall warts that I had lying around I chose the pin
out of the RS-232 connector to match the Acroname Serial
Interface Connector that you can get from www.
junun.org/MarkIII for about $10 Finally, the
programming connector is chosen to fit the cable on
my Microchip ICD2 so that I can just plug in and program
the board without constantly taking the part out of a
programmer board and plugging it back into my test board
If your programmer allows In Circuit Serial Programming
(ICSP), then get a connector that matches its cable
Figure 5 shows what my board looks like I put little
rubber feet on the bottom to make it extra spiffy looking I
put a small three-pin socket on my board so that I could
swap around IR demodulators that have the same pin-out
as the Panasonic units, should I so desire
Now that we understand the formats and we have a
board to look at the signals, how can we decode them?
The answer is software, of course I like to use C as my
programming language, but the logic that I use here can be
ported to any compiler language that you feel comfortable
with I should qualify that statement — any compiler that
allows interrupts to be used is required In this case, my
compiler of choice is the CCS C compiler for the Microchip
14-bit cores (the PIC16Fnnn series.) I am not going to go
into the gory details about how to program a PIC; whole
books have been written on that subject and that isn’t my
intent with this column However, you can benefit from my
line of reasoning for doing things how I did them and move
these procedures to your compiler or even your other
microcontroller if you wish I’m only going to show SONY
and NEC decoding in my code This is because I don’t have
any RC-5 remotes; all of mine were SONY and NEC formats
My test code has two sections in it The first is the
set-up of the interrupt routine that will capture the timesbetween pulses by measuring between falling edges on the INT line When the IR transmitter is On, this will bedetected by the PNA4602 and it will drop its output low.This is why I chose falling edges; the output of the device
is normally high, or Off Before I go into my logic for detecting pulses and parsing them out, let’s get an idea ofhow I set the PIC up to look for these transmissions To dothat, let’s look at how to initialize this PIC The code snippetbelow shows how I set up the timers:
//Turn off comparator setup_comparator(NC_NC_NC_NC);
//We will be doing interrupts setup_timer_0(RTCC_INTERNAL | RTCC_DIV_128);
//16ms timer setup_timer_1(T1_INTERNAL | T1_DIV_BY_4);
//Gives 131ms max timeout ext_int_edge(H_TO_L);
//IR IRQ on falling edge
CCS does a good job of hiding the ugly details of thehardware from you, but you still need to read your datasheets to understand what they are hiding! Here we turnoff the comparators because these pesky things default to
on in the PIC and will get in the way of those I/O lines.We’re going to use TMR0 to time our pulses because it
is an eight-bit timer and we don’t want all that much resolution in our times This “slop” allows us to quicklycheck a bit time and save it away; the coarseness of themeasurement allows us to read remotes that are close, butnot perfect to the specified times We know that the pulses
in SONY and NEC are between 1.2 ms and 13.5 ms (seeTables 1 and 2 again) so we want this timer to have a maximum time before it rolls over that is near that maximum time Since our PIC is running on its internal
8 MHz clock (which is divided by four internally), we knowthat if we use the prescaler on TMR0 at divide by 128, wewill have a maximum time of:
(1/(2MHz/128))*256 = 16.384 msFigure 5 IR detector board and Acroname serial connector.
Trang 20That is pretty close to 13.5 ms Why are we using
TMR1? When we start saving times to measure for our
data bits, we need some way to stop looking if the signal is
interrupted, otherwise we’ll just appear to “hang” and do
nothing TMR1 will be set to values that are just a little
larger than the inter-packet repeat rate For NEC, this is
108 ms; for SONY, it is 45 ms TMR1 is a 16-bit timer and it
only has four prescales to choose from, so I took the one
that got me close to 108 ms Finally, I set the INT interrupt
to trigger on a high-to-low transition for my measurements
Here is the code for the actual interrupt service routine:
#int_global
void isr(void)
/*
* Lets handle all ISR save/recovery functions, the
default isn’t lean enough for
* an ISR that is highly time critical.
//We only have two interrupts, so if it isn’t
this one, it’s the other.
if (bit_test(PIR1,0)) //Timer1 overflow IRQ
{
bits[wBits++] = 255; //timed out bit_clear(PIR1,0); //Clear TMR1 int flag bit_clear(T1CON,0); //Turn TMR1 off until
bit_set(T1CON,0); //turn TMR1 back on so
//we can time out TMR0 = 0; //clear out the timer }
if (wBits == MAXBIT) //rollover the bit
//buffer wBits=0;
to be saved during an ISR call This means that we need to
do it Really, the only reasonable way to do this is withsome simple assembly code This function needs to be FAST and we do that by keeping it lean I combine this lean ISR with the definitions at the top of the program thatlooks like this:
unsigned char save_w; //These next 3 bytes
//are saved on interrupt
#locate save_w=0x7f unsigned char save_status;
#locate save_status=0x7e unsigned char save_FSR;
#locate save_FSR=0x7d unsigned char wBits=0; //To make access to
//these variables fast
#locate wBits = 0x7c //Keep them in common
//memory for ISR use unsigned char t1h;
#locate t1h = 0x7b unsigned char t1l;
#locate t1l = 0x7a /*
* Give me direct access to several SFR’s that CCS doesn’t handle the way I want.
Now look at the ISR from above When we get aninterrupt from INT, we record the value in the TMR0 register
in the next available data slot in our ring buffer (called ringbecause it rolls over to 0 when it reaches the end of the
“ring”) If we time out on TMR1, then we stuff a 255 intothe buffer telling the decoding routine that we timed outand we should ditch the entire set of numbers and wait forthe next start to be detected
The second part of the program will decode the timessaved in the buffer and turn them into 1s and 0s It uses itsown pointer into the ring buffer and knows when to lookfor a value when the read pointer is different from thewrite pointer I’ve put lots of comments into this code, soI’m not going to go over it line-by-line Here is what the bitdecoding routine looks like:
Trang 21unsigned char DecodeBit(unsigned char time)
/*
* This will determine if the bit is a 0 or a 1,
* by whichever standard is in being used
* Returns a 1 if a logic 1 bit, 0 otherwise.
*/
{
unsigned char ret = 0;
unsigned char val = 0;
val = time; //Can be used to “fuzzy”
//the time for rounding
if (whichOne == NEC)
{
if ((val <= NEC_ONE+FUZZY) &&
(val >= NEC_ONE-FUZZY)) ret = 1;
else if ((val <= NEC_ZERO+FUZZY) &&
(val >= NEC_ZERO-FUZZY)) ret = 0;
There is more magic in DecodeCode() that shows how
to recognize the start of a transmission and how to end
one This little routine above simply shows the decoding of
a single data bit Notice the + and – FUZZY settings IR
specs allow for about a 10% slop in the standard times
This FUZZY setting gives us that You can experiment with
how large you want that FUZZY to be since it is a #define
at the top of the program I’ve found that a setting of 2
works well
My code will “auto” detect NEC
code if you hold the button down
This is because NEC uses the repeat
code frame that is distinct from any
other transmission You don’t have to
do that if you don’t want to, and
you’ll need to reset the PIC to get it to
pay attention to SONY codes again
regardless I have two modes of
operation that can be selected by the
setting of the TEST define If this is set
to 1, then the program will only print
out the times This is useful for when
you are trying to understand a new
format If TEST is set to anything else,
then the program will decode either
SONY or NEC, and print out the
device and control codes when they
are received The entire program
source can be found on the SERVO
website www.servomagazine.com).
It is called IRdecoder.c
Conclusion
Figure 6 shows my collection of IR remotes that I used
to test my program I found interesting departures from theestablished standards in some of them; no doubt you will, too.I’ve given you a powerful tool that you can use to discover IR codes and a basic template that you can use
to embed the ability to control your robot using a commonhousehold device: the IR remote Have fun and be creative
If you have any questions about this program or how I
“figured it all out,” send your questions to roboto@servomagazine.com — I’m happy to answer! SV
NEWS FLASH! At the last possible moment I discovered
this site It is an excellent compendium of various IR
remote formats: www.rhoads.nu/bjorn/hp48/remote.
Figure 6 A selection of IR remotes.
Trang 22Know of any robot competitions I’ve missed? Is your
local school or robot group planning a contest? Send an
email to steve@ncc.com and tell me about it Be sure to
include the date and location of your contest If you have a
website with contest info, send along the URL as well, so we
can tell everyone else about it
For last-minute updates and changes, you can always
find the most recent version of the Robot Competition FAQ
at Robots.net: http://robots.net/rcfaq.html
— R Steven Rainwater
J uly
7-11 Africa Championship Robotics Competition
Pretoria, South Africa
Students from various countries and continentswill compete in several robot challenge
events
www.nydt.org/home.asp?pid=9638-10 European Micro Air Vehicle Competition
Research Airport, Braunschweig, Germany
Tiny, autonomous flying robots compete forprizes Every year, these things get smaller and smaller
www.mav08.org8-11 Botball National Tournament
Norman, OK
Educational robot contest for middle and high school students designed to use science,technology, engineering, and math to solve real world problems
www.botball.org13-17 AAAI Mobile Robot Competition
www.livingjungle.com22-25 FIRA Robot World Cup
Shinan Software Park, Qingdao, China
This competition has events for every kind ofrobot soccer imaginable, ranging from thehumanoid robot league down to the tiny Khepera robot league
www.fira.net
26 RoboBombeiro
Polytechnic Institute of Guarda, Guarda, Portugal
Autonomous fire-fighting robot contest
http://avdil.gtri.gatech.edu/AUVS/IARC LaunchPoint.html
29 AUVS International Underwater Robotics
Suzhou, China
Soccer Simulation — teams demo and test theirrobots; Small-size Robot Soccer — F180 robotsplay soccer; Mid-size Robot Soccer — larger robotsplay soccer; Sony Legged Robot Soccer — legged
Send updates, new listings, corrections, complaints, and suggestions to: steve@ncc.com or FAX 972-404-0269
Trang 23robots play soccer; RoboCup Junior — small robotsplay soccer; Humanoid Soccer — humanoid robotsplay soccer; Rescue Robots — NIST StandardRescue Robot Test Field; RoboCup@Home — realworld robot event.
http://www.robocup.orgTBA War-Bots Xtreme
Saskatoon Saskatchewan, Canada
“Robots” (RC vehicles) attempt to destroy eachother
The Science Place, Dallas, TX
Autonomous robots demonstrate their talents
www.dprg.org/competitionsTBA Robot Fighting League National
Minneapolis, MN
“Robots” (RC vehicles) attempt to destroy eachother
www.botleague.comTBA Robots at Play
City Square, Odense, Denmark
Robots compete to demonstrate playfulness andinteractivity
Extreme Robot Speed Control!
6 Dual 2.5A (6A pk) H-bridges
6 Plus 12A fwd-only channel
6 5V - 18V
6 1.6“ x 1.6” x 0.5”
$79.99 Scorpion Mini
6 2.5A (6A pk) H-bridge
6 14V - 50V - Dual 80A H-bridges - 150A+ Peak!
6 Adjustable current limiting
6 Temperature limiting
6 Three R/C inputs - serial option
6 Many mixing options - Flipped Bot Input
6 Rugged extruded Aluminum case
6 4.25" x 3.23" x 1.1”
e Sidewind r
$29.99
$399
Introducing Dalf
6 Closed-loop control of two motors
6 Full PID position/velocity loop
6 Trapezoidal path generator
6 Windows GUI for all features
6 Giant Servo Mode!
6 C source for routines provided
6 PIC18F6722 CPU
25
$ 0
MADE IN THE USA
H-bridges: Use with Dalf or with your Micro/Stamp
Trang 24Robotic Operations Result in
Significant Data Collection
from Mars
IEEE (Institute of Electrical and
Electronics Engineers) has named
Paul Backes, Eric T Baumgartner, and
Larry Matthies recipients of its 2008
Robotics and Automation Award The
three are being recognized for their
contributions to different robotics
technologies used in space flight
systems including the successful Mars
Exploration Rover (MER) mission
rovers Spirit and Opportunity, which
to this day are still functioning on
the surface of Mars The IEEE is the
world’s leading professional
association for the advancement of
technology
The award, sponsored by the
IEEE Robotics and Automation
Society, recognizes Backes,
Baumgartner, and Matthies for
contributions to robotics enabling
effective autonomous operations of
science investigations under extreme
conditions on the planet Mars The
award was presented to the three
on May 23, 2008 at the IEEE
International Conference on Robotics
and Automation (ICRA) in
Pasadena, CA
The works of Backes (distributed
and remote operations),
Baumgartner (manipulator control),
and Matthies (navigation systems)
have advanced robotic technology,
particularly rover operations, and
made possible the scientific
exploration of Mars MER is the first
long-term mobile autonomous
robotic exploration in an unknown
space environment
An IEEE member, Backes is the
technical group supervisor of the
Mobility and Manipulation group in
the Mobility and Robotic Systems
section at the Jet Propulsion
Laboratory of the California Institute
of Technology in Pasadena Heconceived and led the development
of an interface system to allowscientists and engineers tocollaborate in generating activitysequences, which was used as theprimary science planning tool in the
2003 MER mission The interface alsoenables the public to view missiondata and simulate their own activitysequences Backes holds sevenpatents, has won several awards,and has published numerous bookchapters, articles, and papers He
was associate editor of the IEEE Robotics and Automation Society Magazine from 1993 to 1998.
Baumgartner contributed tothe MER project as the lead systems,test, and operations engineer forthe MER Instrument PositioningSystem This system was responsiblefor the robotic deployment andplacement of four in-situ — meaning
“in place” — instruments onto theMartian surface through the use
of a five degree-of-freedom roboticarm Presently, Baumgartner is thedean of the T J Smull College ofEngineering at Ohio NorthernUniversity in Ada He has publishednumerous papers in the area ofmobile robotics and vision-guidedmanipulation and has receivedseveral awards for his efforts on theMER project
Matthies’ work on autonomousnavigation of robotic ground andair vehicles led to the development
of algorithms for descent motionestimation, visual odometry, andreal-time 3D perception with stereovision These capabilities wereincorporated into the MER mission,providing landers with the ability toestimate horizontal velocity androvers with the ability to detectobstacles and measure slip Hiswork can be found in terrestrialapplications including off-roadautonomous navigation and roboticvision systems An associate member
of the IEEE, Matthies is an adjunctprofessor at the University ofSouthern California and a member
of the editorial boards of the
Autonomous Robots Journal and the Journal of Field Robotics He has
received several awards, holds twopatents, and is widely published
Blo w Out Special
$9.95!
WWW.SERVOMAGAZINE.COM
Trang 25Ask for our FREE 96 page catalog
VISIT OUR ONLINE STORE AT
www.allelectronics.com
WALL TRANSFORMERS, ALARMS,
FUSES, CABLE TIES, RELAYS, OPTO
ELECTRONICS, KNOBS, VIDEO
ACCESSORIES, SIRENS, SOLDER
ACCESSORIES, MOTORS, DIODES,
HEAT SINKS, CAPACITORS, CHOKES,
TOOLS, FASTENERS, TERMINAL
STRIPS, CRIMP CONNECTORS,
L.E.D.S., DISPLAYS, FANS,
BREAD-BOARDS, RESISTORS, SOLAR CELLS,
BUZZERS, BATTERIES, MAGNETS,
CAMERAS, DC-DC CONVERTERS,
HEADPHONES, LAMPS, PANEL
METERS, SWITCHES, SPEAKERS,
PELTIER DEVICES, and much more
Trang 26Baby Orangutan B-168
Robot Controller
Pololu announces the release of
the Baby Orangutan B-168 robot
controller, the latest addition to Pololu’s line of
Orangutan robot controllers The compact module
has dimensions of 1.2” x 0.7”, and it can be configured
to fit in a solderless breadboard or a 24-pin dual in-line
package (DIP) socket For applications with low I/O usage,
the Baby Orangutan B-168 board can also be configured
with pins on just one side of the module for use as a single
in-line package (SIP) The diminutive size of the Baby
Orangutan B-168 makes it well suited for primary control of
miniature robots or for auxiliary control on larger robots
The Baby Orangutan B-168 is based on an Atmel
ATmega168 microcontroller running at 20 MHz with 16
KB of Flash program memory and 1 KB data memory
The use of the ATmega168 microcontroller makes the
Baby Orangutan B-168 compatible with the popular
Arduino development platform Free C and C++
development tools and libraries are also available
Integrated motor control sets the Orangutan family
of controllers apart from other small microcontroller
boards, and the Baby Orangutan B-168 features dual
high-performance, MOSFET-based H-bridges to deliver up
to 1A per channel over the 5-13.5V operating range
With hardware-based ultrasonic PWM generation, two
independent, bidirectional DC motors can be controlled
symmetrically and without any processor overhead
The unit price is $29.95
For further information, please contact:
PC Windows USB Inter face for
OWI-535 Robotic Arm
The robotic arm interface kit available from Images
connects OWI’s 535 Robotic Arm Edge™ to a personal
computer (IBM PC or compatible) The interface connects
to the PC’s USB port The software for the interfacepermits real time control and contains a built-in interactive script writer A user may write a script thatcontains up to 99 individual robotic arm functions(including pauses) into a single script file Script filesmay be replayed automatically for demonstratingcomputer controlled automation and animatronics.The Robotic Arm PC Interface creates a fun way oflearning and experimenting with computer automationand animatronics
The USB OWI-535 Interface (assembled and tested)costs $99.95; the USB OWI-535 Interface Kit (requiressoldering and assembly) is $84.95
The Interface Kit Includes:
• Windows 2000/XP/Vista program
• Printed circuit board for easy construction
• All components
For further information, please contact:
Motor Mount and Wheel Kit
It’s time to give your robot the mobility and style itdeserves with the new Motor Mount and Wheel Kitwith Position Controller from Parallax Powerful 12 VDC,
150 RPM motors are combined with precision machined
6061 aluminum hardware to provide enough power,strength, and beauty to make other robots jealous
Fax: 702•262•6894 Email: www@pololu.com Website: www.pololu.com
Pololu
Corporation
Trang 27Conveniently positionedscrew holes in the bearingblock make mounting thiskit a breeze, and theincluded six inch pneumatic rubber tiresperform well on a variety ofsmooth or rugged terrains Thekit includes two position controllers whichuse a quadrature encoder system to reliablytrack the speed and position of each wheel with
36 positions/rotation resolution and report the data
on command via a 19.2 kbps serial bus The position
controllers can also be interfaced with HB-25 motor
controllers (sold separately) to automatically provide
user-definable smooth speed ramping and accurate position
control, which frees up the main processor to handle
more important tasks
The entire Motor Mount and Wheel Kit (#27971) is
a value at $279.95
For further information, please contact:
Flowcode for ARM
Microcontrollers
Matrix has recently
launched a newversion of their popular
graphical programming
language for
micro-controllers — ‘Flowcode
for ARM
micro-controllers.’ Now, 32-bit
ARM microcontrollers
are available for the
same price as eight
bit micros but offer
massive advantages to
developers: low power,
more I/O lines, several
times more ROM and
RAM than a typical eight bit micro, full floating point
and maths libraries, and a massive increase in processing
speed and power
This new version of Flowcode provides
engineers and developers access to all of these features
of the ARM based on Atmel’s popular range of AT91
microcontrollers Flowcode for ARM is also backwards
compatible with Flowcode for PICmicro®
microcontrollers and AVR® microcontrollers which
provides an easy migration route to 32 bit power
ARM hardware development tools, based on the Matrix’s E-blocks range, are also available A fully functional demonstration version is available on theMatrix website
For further information, please contact:
Four-Channel Digital Battery Test System
The Cadex C8000 is an advanced battery test systemcapable of performing complex lifecycle tests Thesetests may include discharging a battery with GSM,CDMA, or other pulses of choice Replicate battery runtime of a power tool, digital camera, or computingdevice by first capturing the current profile and thenapplying the load on the test battery for verification TheC8000 can also test the function of a Li-ion charger, verify battery safety circuits, and read SMBus registers.Automated programs assure safe charging and correctdischarge terminations; custom programs provide foruser-defined settings Each of four independent channelsdelivers up to 10A and 36V, with 0.1% FSR Total power
is 400W on charge and 320W on discharge The CadexC8000 runs as a stand-alone unit or with PC-BatteryLab™software
For further information, please contact:
SOFTWARE
TOOLS & TEST EQUIPMENT
Is your product innovative, less expensive, more functional,
or just plain cool? If you have a new product that you
would like us to run in our New Products section, please
email a short description (300-500 words) and a photo ofyour product to:
Website: www.cadex.com/c8
CadexElectronics
Trang 28Featured This Month:
ROBOT PROFILE – Top
Ranked Robot This Month:
31 Billy Bob by Kevin Berry
Idesigned this 12 pound,Hobbyweight, robot with thepurpose of cramming as muchpower as I could into the smallest
box possible It’s low, it’s fast,and it’ll just keep slamming itsface into your spinning weaponuntil something breaks The horns
on top allow it totake its opponentsinto the wall of the arena whilewearing them like apolished metal hat.Apollyon won itsdebut tournamentthis past Decemberwith a 3-1 record
Trang 29Figure 1 is a CAD model of
Apollyon drawn in SolidWorks Some
minor changes were made, but most
of the parts are almost identical to
the ones in the drawing, for example,
the side and internal frame rails, as
well as the horns that are used to
catch other robots The horns are
steel and the rest of the frame is
6061 aluminum (see Figure 2)
The sides of the frame are
lined up to show the profile of the
chassis, shown in Figure 3 The
holes in the top, front, and bottom
of the plate are tapped to allow
armor to be bolted directly to them
Figure 4 shows the chassis with
the baseplate, drive motors, and
inter-nal portion of the front armor installed
Figure 5 shows a mostly
assembled Apollyon sitting inside
the chassis of my 60 lb robot Ruiner
In Figure 6, Apollyon has been
painted, the front steel wedge has
been mounted, and the robot isalmost ready for competition
Take a look at Figure 7
You’ll see an internal shot ofApollyon the night before the
“Wreck the Halls” event inGreensboro, NC This showsthe layout of the electricalcomponents and the batterymount The piece of PVC pipe
in the back left of the robotserves as a power distributionblock and battery mount
Figure 8 shows Apollyon atWreck the Halls being prepared forthe first match of the competition
Apollyon won the 12 lb classwith a 3-1 record (see Figure 9)
The damage was all cosmeticand easily repaired The shaft collar
on the visible axel was torn off incombat A new front wedge isbeing designed to reduceimpacts on the chassis SV
• Victor 883 speed controller 2 $139.99
• GB42 gearbox 2 $85.99 (no longer available)
• Mini-EV motor 2 $8.99
• 18V 1,650 mAh NiMH battery pack $62.50
• Spektrum DX6 with BR6000 receiver 1 $199.99
• 3” Colson wheel with hub 2 $25.00 (no longer available)
(www.cncbotparts.com)
• GWS elevator/aileron mixer $14.99
• S-BEC Super BEC 5V $46.99 (being replaced
with receiver battery pack for future events)
• MS-05 power switch 1 $48.00
• 45A powerpole connectors $1.39/set
• #8 ring terminals $1.99/25
• Deans Wet Noodle Wire — 12 awg $1.25/ft
• Raw metal, nuts, and bolts (www.mcmaster.com and www.onlinemetals.com)
• Wood and plumbing pieces for battery mount — local hardware store
• Machining (www.teamwhyachi.com) NOTE: All items are from www.robotmarketplace.com unless noted otherwise.
Trang 30from inexpensive, low-power imports(such as the drills offered by HarborFreight) to high-performance, name-brand drills (particularly DeWalt).
Unfortunately, drill gearmotors lackconvenient mounting features, oftenhave minimal bearings, and generallycontain slip clutches, making themunsuitable for use in robotic driveand mobility applications withoutmodifications While there are commercially-available modificationkits for some drill gearmotors, mostmotors must be modified by thehobbyist The photos here document
my modifications toDeWalt’s newest andmost powerful drillmotor SV
PHOTO 1 The 36-volt DeWalt DC900KL
contains a gearmotor rated for 750 watts of
power and is capable of a bone-crushing 200
foot-pounds of stall torque in low gear On
paper, this gearmotor should be capable of
moving a 200 pound robot at about five miles
per hour in a 4WD configuration.
PHOTO 3 The original motor mount is shown on the left, with
its twist-lock interface to the gearbox An alternative mount
— machined from a block of magnesium — is shown on the
right Long bolts will be used to assemble the motor mount
to the new gearcase.
PHOTO 2 The gearbox (part #629059-00) and motor (part
#639521-00) are shown without the drill casing They are
mounted to the casing by the small plastic tabs where the
motor and gearbox meet To mount the gearmotor securely
to a robot, we will make a metal replacement for the stock
plastic gearcase.
PHOTO 4 As shown on the left, the first-stage ring gear (part #628002-00) is free to rotate as part of the clutch mechanism To lock this gear
in place, we can machine it down to a square,
as shown on the right The modified gear presses into the motor mount.
PHOTO 5 The DC900KL uses a three-speed gearbox — for robotics use, the gears must
be secured for a single speed The stock gearcase (top) uses a set of molded-in teeth
to keep the ring gears (bottom) from turning when engaged; these have been duplicated in the magnesium gearcase (right).
PHOTO 8 The completed gearcase, with motor and gearbox parts installed, is shown here The parts were made on CNC equipment, but could be made manually with slight simplifications The motor, gearbox, and spare ring gears are available from www.dewaltservicenet com, at a total cost of $110 per motor-gearbox assembly.
PHOTO 7 The gearbox output (left) uses a simple double-D shaft geometry, duplicated in the hardened, high-strength shaft on the right The step in shaft diameter allows the new gearbox to be protected from impacts
by a bronze thrust bearing.
PHOTO 6 The stock gearbox output has an overrunning clutch to prevent back-driving.
Since this can cause the output to lock up under some conditions,
it must be disabled by removing the five pins and outer ring.
Trang 31ROBOT PR FILE
TOP RANKED ROBOT THIS MONTH
Billy Bob has competed in House
of NERC 2006, Motorama 2007,
RoboGames 2007, Franklin Institute
2007, and Motorama 2008
Details are:
● Configuration — Vertical Spinner
● Frame — 2024 milled aluminum
frame
● Drive — Two AstroFlight 940s
with Team Whyachi gearboxes
● Wheels — Two 3.5” Colsons
● Configuration — Two wheel drive
in the rear
● Drive ESC — Two IFI Victor 883s
● Drive batteries — 21.6 volt A123
battery pack
● Weapon — Custom S7 tool
steel single tooth blade at 8,000RPM
● Weapon power — 24 volt NiCd
2,400 mAh battery pack
● Weapon motor — Axi 5330 at
24 volts
● Weapon ESC — Castle Creations
Phoenix HV85
● Armor — Rubber shock mounted
steel and a rear titanium wedge,along with various attachments forother types of bots
● Radio system — Spectrum DX6
● Future plans — Four-wheel drive
version
● Design philosophy — Balance the
drive, weapon, and armor withsmart engineering, and make itcool!
● Builders bragging opportunity —
Billy Bob went undefeated at its firstevent SV
All fight statistics are courtesy of BotRank
(www.botrank.com) as of May 10,
2008 Event attendance data is courtesy
of BotRank and The Builder’s Database
(www.buildersdb.com) as of May 10,
2008.
● by Kevin Berry
Weight
Class Bot Win/Loss Weight Class Bot Win/Loss
150 grams VD 26/7 150 grams Micro Drive 7/1
1 pound Dark Pounder 44/5 1 pound Dark Pounder 23/3
1 kg Roadbug 27/10 1 kg Roadbug 11/4
3 pounds 3pd 48/21 3 pounds Limblifter 12/1
6 pounds G.I.R 17/2 6 pounds G.I.R 11/2
12 pounds Solaris 42/12 12 pounds Surgical Strike 17/7
15 pounds Humdinger 26/4 15 pounds Humdinger 26/4
30 pounds Totally
Offensive 43/13 30 pounds Billy Bob 12/4
30 (sport) Bounty Hunter 9/1 30 (sport) Bounty Hunter 9/1
60 pounds Wedge of
Doom 43/5 60 pounds Texas Heat 11/4
120 pounds Devil's Plunger 53/15 120 pounds Touro 10/0
220 pounds Sewer Snake 43/12 220 pounds Sewer Snake 11/5
340 pounds SHOVELHEAD 39/15 340 pounds Ziggy 3/0
390 pounds MidEvil 28/9 390 pounds MidEvil 3/0
Top Ranked Combat Bots
Rankings as of May 10, 2008
History Score is calculated by
perfomance perfomance at all
events known to BotRank
Current Ranking is calculated by performance at all known events, using data from the last 18 months
History Score Ranking
Billy Bob – Currently Ranked #1
Historical Ranking: #9 Weight Class: 30 lb Featherweight Team: Benson Labs
Builder: Brian Benson Location: Winchendon, Massachusetts
BotRank Data Total Fights Wins Losses
Trang 32If you rely on the Satcom Mag
motor to deliver a deadly blow or
a punishing push to your robotic
opponent, you will want to follow
these simple tips for improved
reliability and performance
Tape the Brush Covers
The quickest tip is to place trical tape over the four brush covers
elec-(see Figure 1) They don’t often come
loose, but losing a brush cap during
an event can be a disaster If yourmotors get particularly hot, youmight need high temperature Kaptontape, however I have never had aproblem with the cheap stuff
Replace the Case Screws (beginner)
The long case screws supplied
by Satcom are 10-32 by 3” stainless
steel with Phillipsdrive heads Theseare not up to heavycombat duty andshould be replaced
I use hex socket cap screws,McMaster-Carr part
#91251A360, forthis; they can betightened morethan the originalscrews and thethreads are betterformed (Figure 2)
The heads of thesescrews aresometimes
too tall for the counterbores in thefront of the motor, so start by grinding the heads down by about.016” (0.4 mm)
Grinding the heads down alsoputs a small burr around the 5/32”hex socket, making it a tight fit onyour hex driver Use the driver towiggle the screw about until itstarts to thread into a hole; afterthe first screw, this becomes veryeasy I like to apply a slathering ofLoctite 243 to make sure the screwsstay put NOTE: If you have a newerfour screw motor, one screw is only2-3/4” long; you will need to cutone of the replacement screwsdown to fit
Replace the Mounting Screws
The tiny 8-32 face mountingscrews always look inadequate tome; if you are mounting the motorwith these screws, I recommend up-sizing them to around 12-24 orM6 Start by removing the frontplate of the Mag motor, leaving thearmature and case in place
brush covers and
the timing marks.
FIGURE 2 Replacement case screws (Insert:
The replacements have far stronger heads.)
FIGURE 3 Aligning the mounting holes with a tapered pin (Insert: Which screw size would YOU trust?)
Trang 33Position the front plate
accurately on your drill press using
a tapered pin made from the shank
of an old drill (see Figure 3) This
will keep the new mounting points
accurately in position; important if
you have a pre-made gearbox to fit
Drill each of the mounting holes
out to fit your preferred screw size;
5 mm for M6 and #17 for 12-24
sized screws
Tap the new holes and take
extra care to remove all the swarf
from the inside of the plate; you
don’t want conductive chips falling
into the armature! Re-assemble the
motor as detailed in previous tips; if
you combine this tip with thestronger case screw tip, you willhave one tough motor
Neutral Timing
Mag motors can be timedslightly advanced or retarded,although I find that advanced timingmakes hardly any difference so Ileave them neutrally timed If youwant to experiment or need toadjust the timing after repairs, here
is the quick way to do it Mark a linealong the case so it meets the rearend bell, as shown in Figure 1 Withthe case screws loosened enough to
just turn the case, rotate the case left until the screws touch amagnet Mark the position of yourline on the rim of the endbell Nowrotate the case left until the screwsstop on the opposite magnets
Mark this position on the endbellrim The marks on the rim representthe extremes of forward andreverse timing; draw a line midwaybetween your two extremes and this is your neutral timing position — too easy! SV
You can contact Nick via his build thread at
Twenty-five bots were registered
Rotunda Rumble was held at the
Mall Of America in Minneapolis,
MN on April 25th Twenty-seven
bots were registered
Smackdown in Sactown IV
was held on April 27th in
Sacramento, CA Eight bots were
registered
BotsIQ: The Competition 2008
was held April 30th–May 4th in
Miami Beach, FL One hundred thirty-five bots were entered
Roaming Robots presentedFenton Manor 2008 on May 4th
in Stoke On Trent, England
Upcoming Events for July-August 2008
D W Robots willpresent
Pennsylvania BotBlast 2008 in Bloomsburg, PA onJuly 12th Seventeen bots wereregistered at press time For more
details, go to www.dwrobots.
com/tournament.html.
War-BotsXtremewill presentWBX-V
“Taking theFifth” on July26th inSaskatoon,Saskatchewan, Canada Nineteenbots were registered at press time
For more details, go to www.war botsxtreme.com.
The North East Robotics Club willpresent House of Benson –Barnyard Brawl in Winchendon, MA,
on July 26th Thirty-six bots wereregistered at press time For more
details, go to www.nerc.us.
RoamingRobotswill presentGuildford
2008 inGuildford, England on June 15th,and UK Champs 08/RAF Fairford inGloucestershire, England on July12th and 13th For more details, go
to www.roamingrobots.co.uk.
RoboCore will present WinterChallenge 4th Edition inAmparo, Sao Paulo, Brazil on July 26th–27th SV
EVENTS
Results and Upcoming Events
Trang 34including car audio, home audio, cellphones, DVD players, laptops, digitalphoto and video recorders, and ofcourse, massive plasma TVs There was
a 150 inch TV at the Panasonic booththat was the talk of the show Imagine
a TV as big as a queen-sized bed hanging on your wall? Seems like onewould have to reinforce the wall just tokeep it from falling down
Most of the booths that are technology specific are organized intoTech Zones, such as USB, ZigBee, Blu-ray Disc, HDMI, Mobile Internet andWiMAX, IPv6, Sustainable Technologies,
CES 2008
Robot Roundup
CES 2008
A s usual, in the second week of January,
over 100,000 technology lovers converged
on Las Vegas for the 41st annual Consumer Electronics Show (CES) The show
went on from 8 AM to 5 PM for four days, and
even then, it was almost impossible to see
everything CES took up 1.8 million square
feet of trade show space, spanning all of the
major convention centers in Las Vegas So much
walking is involved for the attendees, you can
easily blow out your feet unless you are wearing
running shoes.
Just about every electronic consumer device is represented at CES
by Ted Larson
Photo 1
Trang 35and finally, Robotics With just a few exceptions, most of
the robots and robot companies were on display in the
Robotics Tech Zone or in nearby booths
The biggest exhibitor in the Robotics Tech Zone this
year was WowWee (www.wowwee.com) Every year they
seem to have many innovative, new designs and this year
was no exception The most noteworthy items they brought
out were the Femisapien, Tribot, and Rovio Femisapien is a
female counterpart for the popular Robosapien She
dances, poses, and with her 9x degrees of freedom is
capable of 56 interactive functions They had a nice demo
with three of them line-dancing together (Photo 1) She has
a learning mode where you can pose her and learn
sequences for playback, which seems like endless fun I
thought the best feature of all was that when brought in
proximity to a Robosapien, she is the boss and tells him
what to do (sounds a bit like my wife) With an MSRP of
$99, I can see her ending up on the desks of many geeks
for fun and show
Tribot (Photo 2) certainly received the most attention
out of the WowWee group, with the TV crews swarming
around him to get some footage of him doing his demo I
was really surprised at how much personality he had when
they switched him on He has animated ears and a pop-top
head, and goes on and on about how great it is that you
rescued him from his packaging when you turn him on for
the first time He has an omni-wheel, holonomic drive
system which seems to be a new theme for WowWee
robots Several of their newer products are now sporting
omni-wheels, including Rovio Rovio is a WiFi capable,
omni-wheeled robot with a camera and navigation
capabilities It can be tele-operated over the Internet,
with live streaming video of what it sees The notable and
unique technology item here is that it is using the Evolution
Robotics (www.evolution.com) Northstar 2.0 system
for navigation
Northstar is like “micro-GPS” for a robot It uses
constellations of infrared energy beamed onto the ceiling
from a fixed point to determine its location within a room
Rovio is the first use of this technology in a low-cost,
consumer package and it is quite impressive One can set
waypoints for Rovio within the room and it easily find its
way back to them, even if the robot is picked up and
moved At a retail price of $299, it is quite amazing that all
this technology can be packed into such a cool little robot
Since I am on the topic of indoor positioning, it is a
good time to mention the booth of Hagisonic Hagisonic
(www.hagisonic.com) is a Korean sensor manufacturer
which makes an indoor positioning system for robots called
StarGazer StarGazer analyzes the image of an infrared ray
which is reflected from a passive landmark with a unique
ID, mounted on the ceiling From this landmark, it is able to
determine its repetitive position down to 2 cm of accuracy.The technology is similar to that of Evolution RoboticsNorthstar system, although Evolution does not need to stickanything to the ceiling StarGazer is currently manufactured
as a module you can simply mount in a robot, place the IRprojectors in the room with the passive landmarks, and youare ready to go They had a nice demonstration of two littlerobots navigating around on the floor, avoiding obstacles,and mapping their positions (Photo 3)
Meccano showed their new additions to the Spykee
(www.spykeeworld.com) robot line-up All the Meccano
robots are being sold under the ERECTOR brand as a robot
CES 2008 Robot Roundup
“The biggest exhibitor in the Robotics
Tech Zone this year was WowWee ”
Photo 2
Photo 3
Trang 36Erector set The four new robots in the line are Spykee Cell,
Spykee Miss, Spykee Vox, and Spykee Micro, three of which
are designed to cradle your iPod, and allow it to be voice
controlled and give it some personality (Photo 4) Spykee
Cell can be controlled from your cell phone via Bluetooth
and is targeted at both boys and girls Spykee Miss is an
emotional electronic friend targeted at girls that gives you
advice when you ask her a question Spykee Vox is also
voice controlled, an interactive friend, and can be either a
hero or a villain It is targeted primarily at boys Spykee
Micro is a small, little remote controlled robot that looks
similar to its larger counterparts, but is primarily just for
driving around and making noise Again, all the robots are
kits — in the spirit of the ERECTOR brand — and some are
easier to assemble than others When we were packing up
at the end of the show, the Meccano people were looking
to lighten their load for their trip home, so they gave us
several Spykee Micro kits I brought two assembled unitshome, and had great fun with my four-year-old daughterhaving robot races in the hallway with them
About 50 feet from the Robotics Tech Zone was theiRobot booth Among all the consumer robots they showed,the two that were the standouts were the iRobot LoojGutter Cleaning Robot (Photo 5) and the new iRobotRoomba 500 The Looj has piqued my interest ever since itwas announced, although I had never seen one in personbefore I have heard many rumors about what it can andcannot do, so I thought I would ask the tough questions,and see if I could clear some things up In a nutshell, theLooj is a remote controlled robot that is designed to be put
in a gutter and run up and down to dislodge any debris,using a rotating rubber agitator The idea is you climb upthe ladder to the corner of your house, put the Looj in thegutter, and run it up each gutter section, thus minimizing
CES 2008 Robot Roundup
Photo 4
Photo 5
Photo 6
Trang 37the number of times you have to go up and down the
ladder They had a nice little demo with a piece of roof, a
gutter mounted to it that was filled with plastic leaves, and
they would drive the Looj down it and it would throw the
leaves all over the aisle in front of their booth (Photo 6) It
was great fun to see it go
After asking many questions, I came up with all the
things it cannot do, to dispel any myth making It cannot
climb the downspout, you cannot just throw it up on the
roof and let it do the rest, it cannot go around the corners
in your gutters, it is not compatible with ancient gutters,
with weird dimensions, and it won’t do the job all by itself
while you sit down on your lawn with a glass of lemonade
What it can do, it does very well, and is quite amazing Its
paddle is capable of blasting through all kinds of gunk in
your gutters, like pine needles, twigs, and sludge If your
gutters are a standard 2-1/4” size, it is capable of driving
underneath the straps that hold the gutter to the house,
so you can clean long sections If your house was perfectly
square, you would only need to ascend and descend the
ladder four times, thus minimizing your risk of life and limb
by falling off the ladder It is certainly better than the old
method of climbing up there with gloves and a plastic
scoop, and at only $99 for the base unit, it is cheaper than
most lawn and garden appliances
The iRobot Roomba 500 Series (Photo 7) was there,
driving around a little test carpet that anyone could scatter
all kinds of debris on, and it would happily slurp it up Every
time I see a new version of the Roomba I think, okay, what
now, seen this before, ho-hum However, this one has some
great new features that would make me upgrade It has
anti-tangle technology, that detects if it sucked up a carpet
fringe or an electrical cord, and automatically backs it out
of the beater-brush before continuing along and restarting
to clean It has upgraded bump switches which give it a
lighter touch to keep it from scuffing the baseboard or
furniture Also, it has a new Virtual Wall, called a
Lighthouse, that the robot interacts
with to allow it to be contained to one
room until the room is clean, which
then allows it to move onto the next
room and so on, and so on So, one
robot can clean multiple rooms, and
know when it has completed them all
At $349, it is in line with the pricing
of previous Roomba robots, and offers
significant improvements without a
significant increase in price
Roboware (www.roboware.
com.hk) had a booth in the Tech
Zone, where they were showing off an
impressive looking, three wheeled,
holonomic drive humanoid named E3
(Photo 8) I guess 2008 is the year for
holonomic drive humanoids?!?!
Roboware was founded by Mike Kim,
who previously was one of the
researches on the Canadarm space
robot on ISS, was part of the Hubble Telescope rescue project, and has contributed to some WowWee projectssuch as RSMedia, Elvis, and RSG products According toMike, E3 stands for Education, Entertainment, and Emotion,which makes it a platform much like a video game E3 canexpress its emotion through motions (head, arms, body,wheel), light, and multi-media with customized content
It has five login modes: Baby, Teen, House-Keeper, Single,and Silver Each mode has its own unique and updatablepersonality according to the user’s age E3 has WiFi built in
so it can be controlled remotely via the Internet andthrough its ad-hoc networking capabilities can be voice controlled, or stream or playback live video It is even capable of doing Sykpe teleconferencing E3 has a big 5”LCD mounted in his chest and runs Windows Mobile edition, so he can do many PDA-type functions, as well The retail price range of E3 will be between $1,500-$2,000and he will be available in the US around November of this year
Robotis (www.robotis.com) returned to CES again this
Photo 7
Photo 8 Photo 9
CES 2008 Robot Roundup
Trang 38year with yet more newthings to show, such as
The Dynamixel servos are designed specificallyfor robotic actuator applications, and are networked together using
a communications bussuch as RS-485 or TTL signaling They are powerful, metal gearedservos with torque up to
64 kg-cm The Bioloid kits(as well as URIA) are constructed from theseservos URIA stands forUbiquitous RoboticInformation Assistant, and
is designed as a researchplatform for working with humanoids It has
a fully embedded PC onboard, running Windows XP, with
peripherals such as USB, LAN, Camera, VGA, WiFi, and a
microphone He has a nice big LCD in his chest so you can
see what is going on with the PC
Other interesting peripherals include a Passive
Infrared Sensor (PIR) and a six-axis gyro for measuring
motion The robot stands 22 inches tall and weighs about
12 pounds In comparison to most of the Robo-One type
humanoids, he is really, really big They didn’t give exact
pricing on this monster humanoid, but they were quite
specific that it is designed for researchers and not the
hobbyist With all the servos and PC onboard, I don’t
imagine he is going to be inexpensive
OLogic was there with plenty of interesting robots to
show (www.ologicinc.com) OLogic is an outsourced
research and development company with a focus on robotics, that I co-founded with Bob Allen Of course, webrought out some balancing robots to demonstrate ourcapabilities to design difficult control systems On the firstday of the show, we realized we could place one on top ofanother and do a Las Vegas acrobatic act, in true Vegasstyle (Photo 10) Needless to say, it always attracted acrowd and the TV people whenever we stacked them up.Dean Kamen, the inventor of many things including theSegway, came by and we were able to snap some photos
of us with Dean and the balancing robots (Photo 11)
NPC Robotics (www.npcrobotics.com) commissioned
OLogic to build a robot to demonstrate a device they havebeen reselling, called a Ribbon Lift (Photo 12) A Ribbon Lift
is a device that takes three stainless steel ribbons rolled up
on a spool like a tape measure, uses a motor to unwindthem, and stitchs them together into a self-assembling, triangular shaped pole Since we just finished the robotbefore CES, we brought it out to show off The robot isappropriately named “Giraffe” due to its long neck it canextend The lift mounted in the robot is capable of raising a
50 pound load to 15 feet, and can collapse down into aspool eight inches high by 20 inches in diameter It is quiteamazing to see it unfurl, and some people commented that
it seemed like magic, like Ali-Babba’s magic rope trick Wemounted a WiFi camera on the top and had it feeding a big plasma display to demonstrate its use for surveillanceapplications We are looking forward to building somerobots using the larger version of the Ribbon Lift that canlift a 500 pound load 25 feet in the air
Two robots I missed at CES this year, but heard about,were robots that showed up for just one day to make a
cameo appearance in the Robotics Trends booth (www roboticstrends.com) They were Pleo (www.pleoworld com) the Camarasaurus, made by UGOBE, and Zeno the Revolutionary Robotic Friend by Hanson Robotics (www zenosworld.com) It was a bummer I missed them both,
but there was so much
to see, and certainlyone couldn’t see it all.Hopefully, I will be able
to catch up with themboth next year SV
Ted Larson is the CEO of OLogic, Inc., and an active member in the Home Brew Robotics Club of Silicon Valley OLogic is an embedded systems research and development company with
a focus on robotics OLogic
is currently working with clients across a wide spectrum
of application domains such
as consumer electronics, toys, medical products, and
Trang 39Getting a valid lower resolution reading of the encoder
is certainly better than high resolution unreliable data
I needed to know how far the motors really moved but
didn’t necessarily need to know with as high of a resolution
as the encoders were providing So, the task at hand was
a way to lower the resolution enough so that I could
always count on the readings and help keep track of the
movements A bit of encoder resolution may be lost but it
should still be close enough for this particular project
Symptoms o of tthe P Problem
I was watching the
encoder counts while running
some robot drive motors
During the initial bench
testing, the motors weren’t
running at full speed and the
results I saw were just as
expected However, things
got interesting when I started
ramping up the speed A very
peculiar thing started
happen-ing The encoder counts
started to rise as expected
but as the motors sped up,
the counts started going backwards! As it sped up somemore, it counted forward again This cycle continued backand forth a bit and then the counts were completely erratic
It appears that the encoder was exceeding the polling timeused by the controller and would start missing pulses athigher speeds Obviously, the encoders were not matched
up well with the controller I’ve seen this happen with myrobot drive base and also when I was using some salvagedencoders from HP scanners and DeskJet printers Wheneveryou see symptoms like this, it should throw up a red flag andmake you take a look to see if this may be the problem
Encoder processor board (component side) Encoder processor board (solder side).
One of the joys of the robotics hobby is mastering the art of interfacing A lot of the parts are already in front of us and we just need to make them work together Recently, I ran into a problem with a pair of quadrature encoders for the drive train on one of my robots The encoders themselves worked fine and were generating perfect quadrature outputs However, they were sending out data faster than the controller could handle at higher speeds As a result, the encoder readings were worthless and could not be trusted.
by Robert Doerr
Trang 40Methods o of C Correcting tthe
Problem
There are a few different methods of fixing this
problem In a nutshell, we just need to reduce the number
of transitions of the encoder per revolution Obviously, the
encoder itself could be swapped out with a lower resolution
one If feasible, it may be possible to replace just the
encoder disk with one that has a fewer number of holes
Another option is to change the physical placement of the
encoder within the drive train When it is directly attached
to the armature of the motor, it may send out too many
pulses If it was moved downstream to the wheels
themselves or at some point in the gear train, it would slow
down the speed of the encoder It will still be sending the
same number of pulses per revolution of the encoder but it
will be rotating slower so we get the effect we’re after
Instead of altering the mechanics of the encoder — which
isn’t always an option — we can look into electronic means
of scaling the values At first, I considered making something
up with standard logic ICs but an easier and more flexible
option was to use a small microcontroller to help match up
the readings Whatever method is selected, we would like
the encoder to supply as high as possible a resolution
without sending them too fast for the controller to handle
Microcontroller tto tthe R Rescue
I’ve run into this problem with other encoders and
controllers I wanted a flexible solution so I decided to use a
small microcontroller to scale the encoder readings This
ended up being an excellent solution that can be used for
other projects, as well I selected an SX28 processor and
wrote all the code in SX/B This development went really
fast I started building the encoder scaling board one
evening and had a working prototype with the core
functionality the next day Everything is handled by the
single SX28 chip which costs under $3 A few more features were then added and the code cleaned up tomake it more presentable
One of the extra features is the ability to allow a hostcontroller to change the scaling factor on the fly Since itwill accept commands via serial connection, I also added aresonator for the clock timing to ensure the serial communi-cations would be reliable This microcontroller will beinstalled in between the existing encoder and the controller.This way, it can monitor the encoder, condition the signal,and output a virtual encoder signal to the host controller.Quadrature E Encoders 1 101
Many of you already know how tachometers and quadrature encoders work, but for those who don’t, here is
a quick review A tachometer signal only has one signal andtherefore only provides speed information and not anydirectional information It will only tell how fast somethingmoved but not any details about the direction of travel Itcan be used to get an estimate on distance traveled as long
as the direction is known ahead of time However, a problemcan come up if the tachometer stops at a transition (edge)
If there are any vibrations, it can toggle state back and forthand mistakenly give the impression that it is moving It ismore suited to regulate the speed of a motor where distance/direction are not important; just the speed is critical.Adding a second channel makes all the difference! Aquadrature sensor will have two signals 90 degrees out ofphase These two signals are commonly referred to asChannel A and Channel B With these, both position anddirection can be determined The direction is determined bycomparing if Channel A is leading Channel B or if Channel
B leads Channel A The distance can be computed by keeping track of the counts and factoring in the direction
of movement Velocity can be calculated by counting thenumber of pulses per second I’ve seen some references toencoders that state: “If A leads B, for example, the disk isrotating in a clockwise direction If B leads A, then the disk
is rotating in a counter-clockwise direction.”
That may be true for some encoders, but needs to beverified for the particular encoder being used I prefer tojust think of them as two channels of information and look
at which one is leading, then match that to the actual direction of how it is installed in the robot The clockwise/counter-clockwise description isn’t something that lendsitself well to straight quadrature encoders, so keeping itgeneric works out well After all, it shouldn’t matter if it isclockwise/counter-clockwise, right/left, up/down,
forward/back, etc The important part is that two distinctdirections can be determined; the rest is relative
Look at the examples of output from quadratureencoder, through a few cycles
Chan A 0 1 1 0 0 1 1 0 0 1 1 0Chan B 0 0 1 1 0 0 1 1 0 0 1 1
Encoder assembly on robot base.