Cruise Control

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
Newtons Second Law
Laplace Transform
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Transfer Function
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Design Specification

• Rise time
• Overshoot
• Steady-State Error

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Open-Looped System
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Closed-Loop w/ PI Control
Kp 100
Kp 800 and Ki 40
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weight of the car
PI Control Kp 800 and Ki 40
m 500 kg
m 2000 kg
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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 Toyotas Progress, a
  compact luxury sedan, in 1998
  
• First radar-based system Nissans Cima 41LV-2,
  a luxury sedan
  
• First American ACC model Lexus LS 430, in 2000

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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/s2

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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

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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
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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

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Simulation in Highway Merging
By R. Sengupta and Q. Xu
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Acceleration
Dotted Line Desired Acceleration
Solid Line Actual Acceleration
By R. Sengupta and Q. Xu
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Implementation
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Distance Source
Distance Source
ACC Response
CC Response (for comparison)
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Question