Study Of Intelligent Vehicle Longitudinal Speed Plan And Control Technology Based On Double Safety Distance Mode

With the development of the automobile industry,the intelligence of vehicles has become the focus of various companies and research institutions.As the key technology of intelligent vehicle,the longitudinal velocity planning control technology is the basis and focus of vehicle automatic driving.Based on the vehicle safety,comfort and stability,this paper focuses on the intelligent vehicle longitudinal control system.Through the theoretical analysis and the real vehicle test,a speed planning method based on the double safety distance model is proposed to ensure that the vehicle more reasonable speed planning.And for the bottom of the vehicle actuator characteristics,put forward the corresponding speed control solution.In this paper,the general design of the framework of the intelligent vehicle longitudinal system is proposed.The vertical system is divided into the upper level controller and the lower controller of the speed control by using the hierarchical control scheme,and the performance parameters and system design of the longitudinal system should be analyzed constraint.The characteristics of the vehicle’s natural sliding deceleration and the response characteristics of the hydraulic braking system are analyzed in detail.The response time of the vehicle under different braking pressures is obtained and the deceleration law is analyzed.Based on this,the safety distance of the vehicle is analyzed and the intelligent vehicle system Dynamic safety distance calculation formula.Based on the analysis of the longitudinal velocity planning principle and the trapezoidal velocity planning method,a speed planning travel method based on double safety distance model is proposed and the rationality of planning is verified.This method can synthesize the current safety distance and the expected safety distance state information.Based on the selection of the double safety distance selection logic rule and the non-fixed acceleration / deceleration rate processing mechanism,the method can calculate the expected speed within the local planning path more rationally.The vehicle longitudinal driving dynamics model is established,and the basic driving demand force analysis of the vehicle is carried out.Based on the Kalman filter,the ramp angle of the vehicle is estimated and the slope resistance is compensated.According to the real-time speed feedback state of the vehicle,the speed-based vehicle speed convolution control strategy and the speed dynamic-keeping incremental PID control strategy are designed,and the switching logic of the two feedback control strategies is designed.Vehicle braking is designed based on the vehicle actuator characteristics Control Strategy.Based on a domestic car as the prototype to build intelligent vehicle platform and the platform for a large number of real vehicle test,the test selected different experimental parameters and test methods,the test results show that the design of the speed planning control strategy to meet the intelligent vehicle longitudinal Control the overall requirements of the system to improve the vehicle longitudinal control system of rationality and comfort.