Longitudinal Control Strategy of Collision Avoidance Warning System for Intelligent Vehicle Considering Drivers and Environmental Factors

The collision avoidance warning system, as an intelligent assistance driving technology, provides the driver a safety and comfortable driving experience, by transferring early warning signals to avoid collision while detecting potential danger. In view of the shortcomings of traditional safety distance models, this paper focuses on the driver style and environmental factors to establish novel models of warning distance, dangerous distance and expectation safety distance. The fuzzy control was used to analyze the relationship among driver style, environmental factors and vehicle velocity variable with the safety distance. Based on the relative distance and speed, a sliding mode variable structure control method was employed to get desired acceleration for the upper controller, and and a PID method was applied to design the lower controller. The tracking effectiveness of the controller was verified by numerical analyses. The simulating results show that the proposed system, which can enable the rear vehicle to follow the speed change of the front vehicle to remain the expectation safety distance, and to keep the running state safety.