a-next-generation-flight-simulator-using-virtual-reality-for-aircraft-design-work-in-progress

Paper ID #30083A Next Generation Flight Simulator Using Virtual Reality for Aircraft Design Work in Progress Dr.. A Next Generation Flight Simulator Using Virtual Reality for Aircraft De

Paper ID #30083

A Next Generation Flight Simulator Using Virtual Reality for Aircraft

Design (Work in Progress)

Dr Dominic M Halsmer P.E., Oral Roberts University

Dr Dominic M Halsmer is a Professor of Engineering and former Dean of the College of Science and Engineering at Oral Roberts University He has been teaching science and engineering courses there for 28 years, and is a registered Professional Engineer in the State of Oklahoma He received BS and

MS Degrees in Aeronautical and Astronautical Engineering from Purdue University in 1985 and 1986, and a PhD in Mechanical Engineering from UCLA in 1992 He received an MA Degree in Biblical Literature from Oral Roberts University in 2013 His current research interests involve virtual reality flight simulation, the integration of faith and learning, contributions from the field of engineering to the current science/theology discussion, reverse engineering of complex natural systems, and the preparation

of scientists and engineers for missions work within technical communities.

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A Next Generation Flight Simulator Using Virtual Reality for Aircraft Design (Work in Progress)

ABSTRACT

A multidisciplinary team of five engineering students in the undergraduate program of Oral Roberts University is continuing the development of a fully functional flight simulator to assist in the design of original aircraft Through faculty and staff guidance and a plethora of data from the previous team's endeavors, much progress is expected by April 2020 The ultimate goal

of this project is to develop an innovative approach to deepen the understanding of aircraft design through the use of the flight simulator With this technology, students can produce

realistic motions of flight through virtual reality and six degrees of freedom of a Stewart

platform with revolute joints

The flight simulator provides a state-of-the-art learning tool for students Linking the HTC vive virtual reality headset to the mechanical part of the system provides an exciting

learning experience However, improvements have been made to the previous team’s original design Bigger motors that have been installed on the Stewart platform provide a larger torque for a better experience and also help with carrying the weight of the user sitting in the flight simulator chair Modern engineering tools shows how various engineering skills and software are used in coordination to create a functioning system This gives prospective college students a good perspective on what engineering entails At the same time, aircraft design students can make use of the flight simulator to mimic projects they might encounter in their professional careers Full-size industry flight simulators are very expensive to build and operate Our smaller flight simulator is less expensive, giving more opportunity for virtual reality flight simulation

As part of a growing engineering department, Oral Roberts University offers an aircraft design class The flight simulator will enable students to practically test their theoretical

predictions and make necessary adjustments The advantage is that students can then make more than one virtual aircraft and analyze the differences and similarities to get a better idea of what factors are most important in aircraft design Students can also experiment with random variables

to see what effect they will have on the flight simulation

PREVIOUS RESEARCH AND DEVELOPMENT

In the fall of 2017, a multidisciplinary team of six undergraduate engineering students (with mechanical and electrical concentrations) at Oral Roberts University began an ambitious project to develop the prototype of a Stewart-platform-based single-seat virtual reality aircraft flight simulator to assist in custom aircraft design and promote the excitement of an engineering career among pre-college students in the local area With the support of an intramural grant through the President’s Research Fund from Oral Roberts University, the students’ efforts

continued over the 2017-2018 academic year in the form of a successful senior capstone research and design project, which is required for students majoring in engineering from this university

By the spring of 2018, the prototype was able to simulate the motion of unique aircraft based on

control inputs initiated by the user/pilot in the seat wearing a Vive headset for visual simulation

of the flight experience.1

However, the success of the resulting simulator was somewhat limited because the six motors used to drive the motion were not powerful enough to execute all of the necessary

dynamics without sustaining damage to these motors Toward the end of their project, the team decided that more powerful motors were needed, and inquiry was made for additional funding Adequate additional funds for mew motors was approved and received from the President’s Research Fund during the summer of 2018, but by this time, the original team members had graduated However, installation of the new motors was taken on by the engineering students in the spring 2019 section of ME 450 Aircraft Design The new motors were researched, procured, and installed on the Stewart platform during the spring of 2019 However, testing of the larger motors by these students was severely limited due to the moving of the new School of

Engineering to new facilities (including all new laboratories) during the summer of 2019

Besides the changing of student team members from the original group, this move

brought additional challenges to the project since the simulator and all the associated equipment had to be disassembled and boxed up for the relocation to the new lab space But the move has recently been completed, and now a new multidisciplinary team of five undergraduate

engineering students (three mechanicals and two electricals) has made the completion of the simulator their senior capstone research and design project They started in the fall of 2019 and anticipate completion by the end of the spring semester of 2020, when they plan to demonstrate a fully functional flight simulator The simulator can then be incorporated into ME 450 Aircraft Design during the 2020-2021 academic year In this course, engineering students will get

immediate flight test feedback on their original aircraft designs by modeling their designs in X-Planes Plane Maker and then enjoying a “flight experience” using the virtual reality flight

simulator They can then use this flight performance feedback to make appropriate changes to their aircraft designs Multiple iterations of this type should allow the students to refine their aircraft designs to a higher level than was previously possible

Other universities are also making use of flight testing to assist in the teaching of

concepts in aircraft design Students at the University of Florida enjoy a course in Flight Test Engineering where they conduct a series of flight test experiments involving an original design project This project includes the generation of written technical documents and drawings and the presentation of oral reports to the Federal Aviation Administration to receive approval for

installation of their equipment in an actual aircraft.2 Engineering students in a flight test

engineering course at the U.S Naval Academy collected aircraft performance data in both actual aircraft and a flight simulator Concepts in aircraft design were illuminated by the use of

handheld and standard onboard instrumentation.3 At Tuskegee University, virtual flight tests were found to be an effective pedagogical approach In this setting, engineering students

conducted virtual flight tests, using flight simulator software, to determine various parameters of

an aircraft, and compare their experimental results with the theory The students worked in teams consisting of a flight test director, flight test pilot, and flight test engineer to plan, fly and collect data to estimate factors such as the location of the neutral point of the aircraft.4 This parameter, and others like it, are indispensable when undertaking the complex and creative process of

aircraft design

In a comprehensive article entitled, “Trends in Simulation Technologies for Aircraft Design,” an Engineer-in-the-Loop Simulator (ELS) is found to be effective, and the author concludes that “optimization techniques can be combined successfully with modeling and

simulation to improve the quality and efficacy of the [aircraft] design.”5 These concepts are important features in this project since undergraduate engineering students in future courses will

be designing custom aircraft and then “closing the loop” by virtually piloting the aircraft to test their designs The aircraft modeling and simulation software/hardware will then allow them to optimize their designs as they make informed decisions about design enhancements and assess the resulting flight performance

INTRODUCTION

As Virtual Reality (VR) and simulation technology is growing and being used in multiple real-life situations it is essential that the academic system keeps up with the trend Some of the technology is very expensive and rare but scaling it down enables academic institutions to

provide basic knowledge on innovative concepts Students benefit from the hands-on approach and may even come up with ideas that will revolutionize the academic system as well as

industry A team of five engineering students at Oral Roberts University is continuing

development of a virtual reality flight motion simulator that will be used in an aircraft design class and displayed in the VR educational building at Oral Roberts University

The idea of the virtual flight motion simulator is to combine a Stewart platform, virtual reality and flight simulator software The Stewart platform has already been modelled but the current group has developed additions to make the platform better Virtual reality equipment and computer software have already been purchased but the setup has not been completed

Conceptually, multiple software is combined to work as a single system Computer software used includes X-plane 11, FlyInside, SMC3, and MATLAB Simulink SMC3 uses an Arduino board coded in Java to send commands to the motors and get feedback of their response SMC3

is useful as it combined two motors to work as a unit, then syncs the three sets to facilitate the flight motion simulator to experience all six degrees of freedom The HTC Vive headset is used

to play X-plane 11 which is being run on Steam Using Steam is convenient because it already supports virtual reality and specifically the HTC Vive Another advantage is that Steam is

compatible with FlyInside which is the software used to improve graphics quality and provides the link between X-plane 11 and the mechanical part of the flight motion simulator

For the aircraft design class, students use Simplified Aircraft Design for Homebuilders6 and Aircraft Design: A Conceptual Approach7, both by Dr Daniel P Raymer to design custom aircraft These texts have a lot of complex and time-consuming calculations which will be

lessened by using X-plane 11 because X-plane 11 automatically calculates some of the

parameters However, both the texts and X-plane 11 list fuselage design, wing design, airfoil design, engine selection and landing gear design as the major concepts of aircraft design

Utilizing the texts and X-plane 11, students can experiment with design enhancements and push limits to see how different designs affect flight Students save a lot of time on calculations which enables then to work on more designs and learn more Since aircraft design students will use the flight simulator, they will know first-hand whether their design works, and also evaluate flight performance X-plane 11 is interactive and offers tips on building planes which makes the

aircraft design class student-friendly The simulator also enables non-engineering students to experiment with flying since they will not need to know all the engineering concepts covered in aircraft design

Virtual reality is being used in many industries, so the group decided to utilize its power for educational purposes An HTC Vive headset is the preferred choice but other options such as the Oculus Rift and the Valve Index can also be used The Oculus Rift has lower quality than the Vive and the Valve Index is currently out of stock Also, Oral Roberts University offered an HTC Vive to use for the project The flight motion simulator will be set up in the VR educational room of the Global Learning Center at Oral Roberts University Students and prospective

students can tour the room and fly the simulator The experience will draw students towards the school and most importantly towards engineering It also provides motivation for engineering students to experiment and use their imagination

Full size flight motion simulators cost hundreds of thousands of dollars However, the flight motion simulator being developed at Oral Roberts University has a projected cost of

$13,394 dollars The amount includes all the direct expenses for building the flight motion simulator, as detailed in the following tables

Table 1: Actual Mechanical Summary Costs

24V Motors Transmotec WHD123224-24-40 $600 $7450

Fasteners: Bolts, Nuts, and Spacers $300 $250

Total Cost of Mechanical Components: $9,887

Table 2: Actual Electrical Summary Costs

Sabertooth Motor Drive $190 3 $570

Misc Electrical Equipment (connectors, etc.) $30 N/A $30

Total Cost of Electrical Components: $1,930

Table 3: Software Costs

Total Cost of Software Components: $180

Table 4: Additional Costs

Total Cost of Additional Components: $1,397

Table 5: Final Cost Summary

Division Actual Cost

Mechanical $9,887 Electrical $1,930 Software $180 Additional $1,397

Total Cost: $13,394

Labor costs are not included since this project is being developed for educational purposes However, the engineering hours would cost $65,000 at $25 per hour working eight hours a day for five days each week Unexpected expenses are considered in the $13,394 projected cost of the project The planning process and allocation of resources lets students apply lessons from engineering economics Part of the engineering industry is finding ways to make useful products for an inexpensive price As students and other users learn how the flight motion simulator was built, they realize that engineering is more than putting together components, but it is also about meticulous planning and financial wisdom Furthermore, students realize how they can maximize available resources to come up with a working system that can mimic a full-scale aircraft Thus, the flight motion simulator will be educational in many ways

NEUTRAL BOUYANCY SYSTEM

One key element of the enhanced design is a neutral buoyancy system to support the chair in which the user/pilot will be sitting This idea is still in the experimentation stage of trying to design and construct a spring-based system but the team is working hard to complete this task A coil spring is planned for the buoyancy system A spring addition will help with keeping the chair steady, keeping the chair above the base of the system, helping the user have a better experience running a simulation, and relieving some stress on the motors and metal arms Springs are often used in many different types of chairs to help stabilize the weight being put on

it from the user This year’s team believes this will be a great addition to the simulator in making

it the best experience possible for the user

A machine design textbook is being used by the mechanical engineers to help guide them

through the process of creating this neutral buoyancy system The text is Mechanical

Engineering Design by Richard Budynas and J Keith Nisbett.8 In chapter ten of this text it talks about mechanical springs From this chapter the team is gathering information on what design, material, and size of the spring should be used in order to hold the average user’s weight and function to maximum capability when undergoing stress-inducing compressions

Several factors are important to study when designing a spring system as shown in this text The first step is to choose a type of end for the spring Studying the text, the best option for

a spring design is one with squared and ground ends This design allows the best transfer of loads

to be obtained The second step is to decide on a material to be used for the spring The best option for a spring of strength the team is needing is a spring made of Chrome-vanadium

material This type of spring is good for handling high stresses and having long endurance for loadings which the team will need with all the people getting on and off the simulator system, in addition to all the hours of dynamic motion during flight simulations

Figure 1: Squared and ground ends for spring

Table 6: Squared and Ground Formulas for Dimensional Characteristics

Next the team performed several calculations to determine the sizing of the spring that will be needed in the material and styles chosen The max shear stress in the wire, the deflection, stability, tensile strength, shear yield strength, and the max force it can handle all need to be calculated and tested The mean diameter of the coil, the wire diameter, and force that will be

applied to the spring will help in determining these parameters Table 10-4 of Mechanical

Engineering Design gives the allowable diameters of wire and values of strengths for the

material chosen for the spring The value chosen for the wire diameter of chrome-vanadium wire was d = 0.437 inches (A = 169 ksi and m = 0.167) The mean coil diameter chosen for the spring was D = 7.5 inches Following the equations below will give the results shown with these chosen values and a maximum load of F = 300 lb

Sut = A / dm = 194 ksi (Equation 1: Tensile strength)

Ssy = 0.45 Sut = 87.3 ksi (Equation 2: Yield strength)

𝜏 = 8(300𝑙𝑏)(7,5𝑖𝑛)

𝜋(𝑜.437)^3 + 4(300𝑙𝑏)

𝜋(0.437)^2= 70.6 ksi

This provides a factor of safety of 87.3/70.6 = 1.24, which should be adequate since in dynamic situations, the motors will also be assisting in supporting the load

With these equations the different characteristics of the spring chosen are determined These values found are important in understanding the strength and safety of the spring to be used The neutral buoyancy system based on this spring will ensure a steady smooth process of the simulator absorbing the fluctuating load of the user while in motion This new design of a neutral buoyancy system added by the team will continue to be tested and calculated so that the best possible system can be created for the user to have the ultimate learning experience in flight simulation

FIXING THE POTENTIOMETERS AND MOTOR COLLARS

Since accepting the project of designing an aircraft simulator, the senior project group has done many things Before we started, we split into subsections of mechanical and

computer/electrical engineering The goal of the mechanical engineers is to do hands on work with the project, as well as theoretical calculations The first thing that was done was welding together of the collars for the attachment of the motors to the lower arms of the Stewart platform This was vital because these welds will be experiencing the most force on the platform, and they directly translate power from the motors to the platform A Finite Element Analysis to determine the maximum stress in these members is under consideration

Another component that has been worked on is the potentiometers The potentiometers are supposed to have some movement but not full 360 degrees of motion The entire

potentiometer is not supposed to fully rotate, only the top shaft When realizing this, we decided that some sort of metal bracket was needed to go over the potentiometer to protect it from

moving The first step was to measure out the dimensions of the holes on top of the motor so that

we can eventually fabricate pieces of sheet metal to secure them in place The basic idea of the design is to secure the sheet metal to the motor with screws, so that it can bend down and

surround the shaft of the potentiometer while another screw on the potentiometer will secure the bottom piece of sheet metal in place The dimension of the length and width of the platform on the motors where obtained Next to be measured were the diameters of the holes on the motor along with their exact orientation on the platform The specifications of the potentiometer were noted in correlation to the distance from the motor platform We made a few rough sketches, then modeled the sheet metal on SolidWorks (See Figure 2 below) After that, we drew out the design on a piece of sheet metal and will replicate that design for all six motors This design with sheet metal worked out well, obviating the need to come up with an alternate design

Figure 2: SolidWorks Model of Potentiometer Brackets

The next step after designing is testing, so the group can properly get the flight simulator completed We were able to test the potentiometers, but we realized by seeing them and testing

on the computer that half of the potentiometers were not working or not reading properly through the computer Some of them provided false reads because the wiring was not properly soldered

on the potentiometer It could be that they were damaged during the move to the new laboratory facilities To be safe, we ordered all new potentiometers, so we could replace all of them instead

of half For the Arduino to read them, we need to take off the old ones and reassemble the new ones and correctly solder all the wires together Once this is done, we should be able to complete our testing

Some other mechanical modifications to the simulator also had to be conducted The collars to bolt the arms of the Stewart platform to the motors needed to be changed so they fit the larger motors A larger key had to be welded on the collar using a MIG welder This was done for all six motors and they were recently installed They then will connect to the arms so a direct translation of movement can be effectively and precisely executed These translations will come through the input of the user/pilot through the joystick via the VR computer programming Components that will experience the most amount of stress have already been modeled through SolidWorks thus the right metals and materials have been chosen, although a Finite Element Analysis is still to be conducted, as mentioned above The main mechanical task was modifying these collars along with assembly of the final simulator This will be done once the motor and

VR testing is complete Potentiometer brackets for the motors have also been fabricated and fitted so that an accurate reading and response of the motors can be read through the computer The potentiometers are important because they stop sporadic or over rotation of the motors