1. Cruise Control
Karen Lie
Engr 315

2. Outline Introduction to Cruise Control CC Modeling CC Simulation
Introduction to Adaptive Control
ACC Modeling
ACC Simulation

3. Cruise Control System
Input: buttons on the steering wheel, brake, clutch, gas pedal and feedback signal
Processor
Sensor
Output: the throttle position

4. Modeling
Newton’s Second Law:
Laplace Transform:

5. Transfer Function

6. Design Specification Rise time < 5 sec Overshoot < 10%
Steady-State Error < 2%

7. Open-Looped System

8. Closed-Loop w/ PI Control
Kp = 100
Kp = 800 and Ki = 40

9. weight of the car PI Control: Kp = 800 and Ki = 40 m = 500 kg

10. Adaptive Cruise Control
So-called Active Cruise Control (ACC)
Traffic flow characteristics
Collision-avoidance system
Not to be considered as a safety feature by automakers

11. Background
First laser-based system – Toyota’s Progress, a compact luxury sedan, in 1998
First radar-based system – Nissan’s Cima 41LV-2, a luxury sedan
First American ACC model – Lexus’ LS 430, in 2000

12. Function Preset and maintain the car speed
Measure the distance to the preceding car and the relative speed
Adjust the car speed accordingly
Maximum deceleration = 3.5m/s^2

13. Adaptive Cruise Control
Change gear automatically
Function properly in poor weather condition
Cannot pick up non-moving objects
Effective in the speed between 30km-180km/h

14. Two types of ACC Radar-Based System
– Three overlapping radar-beams (76-77kHz)
-- Detects moving object up to 120 m
– work in poor weather conditions
Laser-Based System (lidar)
– less expensive and easier to package
– light beams are narrower than water droplet and snowflakes

15. Radar-based Adaptive Cruise Control

16. Modeling in Highway Merging
ACC Controller
Desired Range
By R. Sengupta and Q. Xu

17. Highway Merge-In Scenario
1. At 0 sec, the preceding vehicle is traveling 12.5 m/s
2. The follower vehicle w/ACC is 150 m behind the preceding vehicle and is traveling at 25 m/s
3. At 10 sec, the third vehicle cut in in between the two vehicles

18. Simulation in Highway Merging
By R. Sengupta and Q. Xu

19. Acceleration Dotted Line = Desired Acceleration
Solid Line = Actual Acceleration
By R. Sengupta and Q. Xu

20. Implementation

21. Distance Source
Distance Source
ACC Response
CC Response (for comparison)

22. Question