This document discusses cruise control and adaptive cruise control systems. It provides an introduction and outlines modeling, simulation, and implementation of cruise control and adaptive cruise control. Specifically, it describes modeling cruise control using Newton's second law and transfer functions. It also discusses modeling adaptive cruise control for highway merging scenarios and simulating the acceleration response of adaptive cruise control when another vehicle cuts in.

1. Cruise ControlCruise Control
Karen LieKaren Lie
Engr 315Engr 315

2. OutlineOutline
►Introduction to Cruise ControlIntroduction to Cruise Control
►CC ModelingCC Modeling
►CC SimulationCC Simulation
►Introduction to Adaptive ControlIntroduction to Adaptive Control
►ACC ModelingACC Modeling
►ACC SimulationACC Simulation

3. Cruise Control SystemCruise Control System
► Input: buttons on theInput: buttons on the
steering wheel, brake,steering wheel, brake,
clutch, gas pedal andclutch, gas pedal and
feedback signalfeedback signal
► ProcessorProcessor
► SensorSensor
► Output: the throttleOutput: the throttle
positionposition

4. ModelingModeling
m s⋅ V s( )⋅ b V s( )⋅+ U s( )
Newton’s Second Law:
m
dv
dt
⋅ b v t( )⋅+ u t( )
Laplace Transform:

5. Transfer FunctionTransfer Function
Y s( )
U s( )
1
m s⋅ b+

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

7. Open-Looped SystemOpen-Looped System

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

9. weight of the carweight of the car
m = 500 kg
PI Control: Kp = 800 and Ki = 40
m = 2000 kg

10. Adaptive Cruise ControlAdaptive Cruise Control
►So-called Active Cruise Control (ACC)So-called Active Cruise Control (ACC)
►Traffic flow characteristicsTraffic flow characteristics
►Collision-avoidance systemCollision-avoidance system
►Not to be considered as a safety feature byNot to be considered as a safety feature by
automakersautomakers

11. BackgroundBackground
►First laser-based system – Toyota’sFirst laser-based system – Toyota’s
Progress, a compact luxury sedan, in 1998Progress, a compact luxury sedan, in 1998
►First radar-based system – Nissan’s CimaFirst radar-based system – Nissan’s Cima
41LV-2, a luxury sedan41LV-2, a luxury sedan
►First American ACC model – Lexus’ LS 430,First American ACC model – Lexus’ LS 430,
in 2000in 2000

12. FunctionFunction
► Preset and maintain the car speedPreset and maintain the car speed
► Measure the distance to the preceding car and theMeasure the distance to the preceding car and the
relative speedrelative speed
► Adjust the car speed accordinglyAdjust the car speed accordingly
► Maximum deceleration = 3.5m/s^2Maximum deceleration = 3.5m/s^2

13. Adaptive Cruise ControlAdaptive Cruise Control
►Change gear automaticallyChange gear automatically
►Function properly in poor weather conditionFunction properly in poor weather condition
►Cannot pick up non-moving objectsCannot pick up non-moving objects
►Effective in the speed between 30km-Effective in the speed between 30km-
180km/h180km/h

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

15. Radar-based Adaptive CruiseRadar-based Adaptive Cruise
ControlControl

16. Modeling in Highway MergingModeling in Highway Merging
rd t( ) 6.33 v
0.48
⋅ 2+
By R. Sengupta and Q. Xu
ades t( ) kv
t
r t( )
d
d
⋅ kp r t( ) rd t( )−( )⋅+
ACC Controller
Desired Range

17. Highway Merge-In ScenarioHighway Merge-In Scenario
►1. At 0 sec, the preceding vehicle is1. At 0 sec, the preceding vehicle is
traveling 12.5 m/straveling 12.5 m/s
►2. The follower vehicle w/ACC is 150 m2. The follower vehicle w/ACC is 150 m
behind the preceding vehicle and isbehind the preceding vehicle and is
traveling at 25 m/straveling at 25 m/s
►3. At 10 sec, the third vehicle cut in in3. At 10 sec, the third vehicle cut in in
between the two vehiclesbetween the two vehicles

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

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

20. ImplementationImplementation

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