CRUIS CONTROL SYSTEM , LE THANH PHUC

• The cruise control system controls the speed of your car the same way you do - by adjusting the throttle position... • The off button turns the cruise control off even if it is engaged

Le Thanh Phuc

Faculty of Automotive Engineering

University of Technical Education Ho Chi Minh City

Email: phuclt@hcmute.edu.vn

• Cruise control is an invaluable feature on American cars

• Without cruise control, long road trips would be more tiring, for the driver at least, and those of us suffering from lead-foot syndrome would probably get a lot more speeding tickets

• The cruise control system controls the speed of your car the same way you do - by adjusting the throttle position

2

• Hitting the on button does not do anything except tell the car that you might be hitting another button soon

• The off button turns the cruise control off even if it is engaged

3

• The set button tells the car to maintain the speed you are

currently driving

• If you hit the set button at 45 mph, the car will maintain your speed at 45 mph

4

• If you recently disengaged the cruise control by hitting the

brake pedal, hitting the resume button will command the car to

accelerate back to the most recent speed setting

5

• Holding down the coast button will cause the car to decelerate,

just as if you took your foot completely off the gas

6

• The brake pedal and clutch pedal each have a switch that

disengages the cruise control as soon as the pedal is pressed, so you can shut off the cruise control with a light tap on the brake

or clutch

7

• The cruise control system controls the speed of the car by adjusting the throttle position, so it needs sensors to tell it the speed and throttle position

• It also needs to monitor the controls so it can tell what the desired speed is and when to disengage

8

• Two cables connected to a pivot that moves the throttle valve

• One cable comes from the accelerator pedal, and one from the actuator

9

• Many cars use actuators powered by engine vacuum to open

and close the throttle

• These systems use a small, electronically-controlled valve to regulate the vacuum in a diaphragm

10

• Adaptive cruise control is similar to conventional cruise control in that it maintains the vehicle's pre-set speed

• However, unlike conventional cruise control, this new system can automatically adjust speed in order to maintain a proper distance between vehicles in the same lane

• This is achieved through a radar headway sensor, digital signal processor and longitudinal controller.

11

• In a standard cruise control system, the speed of the vehicle is controlled to a desired value using the throttle control input

• The longitudinal control system architecture for the cruise control vehicle will be designed to be hierarchical, with an upper level controller and a lower level controller

12

• The lower level controller determines the throttle input required to track the desired acceleration.

14

• A typical algorithm used for the upper controller is PI control using error in speed as the feedback signal

15

• The plant model for the upper controller is the transfer function between desired acceleration and actual vehicle speed

16

17

18