CRUIS CONTROL SYSTEM , LE THANH PHUC

CRUISE CONTROL SYSTEM Le Thanh Phuc Faculty of Automotive Engineering University of Technical Education Ho Chi Minh City Email: phuclt@hcmute.edu.vn Introduction • • Cruise control is an invaluable feature on American cars • The cruise control system controls the speed of your car the same way you - by adjusting the throttle position 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 CCS explanation • Hitting the on button does not 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 CCS explanation • 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 CCS explanation • 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 CCS explanation • Holding down the coast button will cause the car to decelerate, just as if you took your foot completely off the gas CCS explanation • 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 CCS explanation • 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 CCS explanation • • Two cables connected to a pivot that moves the throttle valve One cable comes from the accelerator pedal, and one from the actuator CCS explanation • 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 CCS explanation • • Adaptive cruise control is similar to conventional cruise control in that it maintains the vehicle's pre-set speed • This is achieved through a radar headway sensor, digital signal processor and longitudinal controller 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 11 CCS operation • 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 13 • The upper level controller determines the desired acceleration for the vehicle • The lower level controller determines the throttle input required to track the desired acceleration 14 UPPER LEVEL CONTROLLER FOR CRUISE CONTROL • A typical algorithm used for the upper controller is PI control using error in speed as the feedback signal 15 UPPER LEVEL CONTROLLER FOR CRUISE CONTROL • The plant model for the upper controller is the transfer function between desired acceleration and actual vehicle speed 16 • The PI controller is: 17 PID controller circuit 18 [...]... 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 13 • The upper level controller determines the desired acceleration for the vehicle • The lower level controller... controller determines the throttle input required to track the desired acceleration 14 UPPER LEVEL CONTROLLER FOR CRUISE CONTROL • A typical algorithm used for the upper controller is PI control using error in speed as the feedback signal 15 UPPER LEVEL CONTROLLER FOR CRUISE CONTROL • The plant model for the upper controller is the transfer function between desired acceleration and actual vehicle speed... explanation • • Adaptive cruise control is similar to conventional cruise control in that it maintains the vehicle's pre-set speed • This is achieved through a radar headway sensor, digital signal processor and longitudinal controller 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 11... signal 15 UPPER LEVEL CONTROLLER FOR CRUISE CONTROL • The plant model for the upper controller is the transfer function between desired acceleration and actual vehicle speed 16 • The PI controller is: 17 PID controller circuit 18