Development of a Controlled Braking Strategy For Vehicle Adaptive Cruise Control

Adaptive Cruise Control (ACC) technology is presently on the horizon as a convenience function intended to reduce driver workload. This paper presents an implementation of a brake algorithm, which extends the production cruise control feature. A brief overview of the system architecture and subsystem interfaces to the forward-obstacle detection system, throttle and engine management controls are described. Considerations of moding ACC with ABS and Traction Control are presented at the vehicle level. This development activity is presented in two major phases. Both phases of this development project utilize CAN controllers and transceivers to implement requirements for limited access highway driving. The initial phase of development requires the brake control to follow a deceleration command and operate “open-loop” to the vehicle controller. Vehicle test data capturing smooth stops on high coefficient surfaces is presented as insight to the braking performance of the vehicle. A follow-on project extends the controlled braking requirements to “brake to a stop” as well as perform low speed cruise scenarios. The paper includes a description of rapid prototyping as an important tool to ensure the quality of the development software and reduce integration cost with core algorithms. Vehicle data summarizing autonomously controlled braking from current development vehicles will be presented.