Chapter 6

Adaptive Cruise Control (ACC)

Introduction to ACC

Adaptive Cruise Control (ACC) technology automatically adjust the vehicle speed and distance to that of a target vehicle. ACC uses a long range radar sensor to detect a target vehicle up to 200 meters in front and automatically adjusts the ACC vehicle speed and gap accordingly.

ACC automatically decelerates or accelerates the vehicle according to the desired speed and distance settings established by the driver. As per standard cruise control the driver can override the system at any time.

Common Terms in ACC• Response time of the driver (t): time needed by the driver to

response safely to any unwanted disturbances (approximately about 2-3 sec)

• Safe distance: the distance between vehicle equipped with ACC to the leading vehicle in front where the driver is still able to response safely in case of emergency brake happened to the vehicle in front

Safe distance = Vs * tVs = speed of ACC vehiclet = 2-3 sec

How ACC works?

System Configuration of ACC

ACC Control

1. Model free control(no equations of motion of the model needed)

2. Model based control(controller is developed based on vehicle system model)

Flow chart of ACC Programming (Model free)

System Description of ACC

Model based ACC control

Engine model

Torque Converter Model

Transmission Model

Vehicle Dynamics Model

Develop Simulink Diagram of Model Based ACC Controller

30 minutes