Research On Control Strategy Of Vehicle Active Collision Avoidance System Based On Coupled Safety Distance Model

According to EURO NCAP,90% of car rear-end accidents are caused by driver distractions and inattention.The vehicle active collision avoidance technology is designed to help the driver avoid or mitigate the harm caused by operational errors,and effectively improve the safety,comfort and road capacity of the vehicle,which is of great significance in the active safety of the vehicle.This paper relies on the school-enterprise cooperation project to study and develop a vehicle active collision avoidance system with high warning accuracy and active braking safety.The main contents of the research are as follows:First,the system functions are defined according to the actual functional requirements of the active collision avoidance system in terms of warning and active braking.On this basis,the overall scheme design of the vehicle active collision avoidance system is completed.The detailed scheme design was carried out from the hardware and software perspectives,and the hardware structure layout scheme and the specific control methods of each function realization were determined.Consider the practical requirements for reasonable warning of the vehicle active collision avoidance system,reducing false alarms and safe braking.Based on the safety distance model maintained by the vehicle spacing,the safety distance model reflecting the driver’s characteristics,the longitudinal safety distance model when the vehicle is changing lanes,the minimum braking distance of the driver’s braking,and the minimum braking distance of the vehicle,these three safety distance models and two boundary conditions establish a coupled safety distance model.Theoretically analyze the excellent performance of the coupled safety distance model in improving vehicle safety and reducing false alarm triggering during lane change.The control strategy of active collision avoidance system is studied by combining theoretical analysis and simulation test.According to the system function requirements of ensuring vehicle safety,maximizing system false alarm rate and false trigger rate,and maintaining reasonable workshop distance,based on the characteristics of vehicle braking ability,driver braking ability and vehicle steering lane change,the control strategy of predictive collision warning,emergency braking assist and automatic emergency braking function of active collision avoidance system is established.Simulation analysis of the triggering distance of each function When the vehicle approaches the stationary vehicle at different speeds,the rationality and effectiveness of the control strategy are verified.Hydraulic characteristics test was carried out on the key components of the hydraulic adjustment unit of the executive layer.The control variable method is used to study the influence of the current intensity of the coil and the duty cycle of the PWM control signal of the hydraulic pump motor on the active boost.According to the requirements of the vehicle active collision avoidance system for rapid supercharging and accurate control of the hydraulic brake system,an active supercharging control method for overflow control is proposed.Finally,the performance of the active collision avoidance system is verified by building a simulation/real vehicle test platform.Based on Carsim vehicle dynamics model and Matlab/Simulink control strategy model,through the joint simulation test of Matlab/Simulink and Carsim,the performance of the system is verified and the control strategy is optimized.According to the system hardware layout scheme,a real vehicle test platform based on the traditional vehicle structure was built.The performance of the vehicle active collision avoidance system based on the coupled safety distance model is verified again by the actual vehicle test.Simulation and actual vehicle test results show that the active collision avoidance system based on the coupled safety distance model proposed in this study can play a good role in early warning and active braking,effectively reduce the false alarm trigger rate of the system,ensure the safety of the vehicle and reasonably control the relative distance of the workshop.