Research On Adaptive Cruise Decision And Control Strategy For Self-driving Vehicles

Autonomous vehicle is an important research direction in the field of automotive technology in recent years.Adaptive Cruise Control(ACC)is one of the key technologies,which can adaptively control vehicle speed and distance according to the driving state and traffic flow of the vehicle in front,so as to improve the safety and comfort of driving.The traditional ACC control method has great fluctuation and deviation when solving speed and distance control problems.Therefore,in view of the existing problems,this paper deeply analyzes the research status and advanced theories at home and abroad,and conducts in-depth research on how to improve the adaptive cruise performance.The main work of this paper is as follows:Firstly,the ACC system architecture and control strategy are analyzed and designed,and the hierarchical control structure is adopted to establish the spacing strategy considering its own speed,target vehicle speed,acceleration and road conditions.The working conditions are divided into constant speed cruise and following working conditions,and the corresponding switching strategy is designed,and the driver priority control mode is added to ensure the safe driving of the vehicle.The corresponding lower controller is designed,including the braking drive switching strategy,the expected driving and braking torque calculation module,the calculated value is transmitted to the brake device or the motor model,the vehicle speed is controlled,and the corresponding model is established.Then,the upper controller is designed under two different working conditions.PID controller is selected to control the speed under the cruise control mode.In the following working mode,the fuzzy controller is selected for distance control,which makes the expected acceleration algorithm meet the characteristics of fast calculation speed,high precision and small fluctuation.In addition,GPS/GIS system and various sensors are used to obtain the curvature of the curve,vehicle speed and road elevation,calculate the vehicle rollover speed threshold,control the vehicle speed on the curve,and improve vehicle safety.Then,the main vehicle and target vehicle models are built,and the electric vehicle includes motor type selection and configuration,radar control model,etc.are designed in detail to facilitate subsequent experimental verification.Finally,the joint simulation platform built by Carsim and Simulink was used to verify the effectiveness of the designed control system,and the designed model was verified and analyzed from three conditions: straight driving condition,curve driving condition and ramp driving condition.