Research On Vehicle Emergency Collision Avoidance Algorithm

Nowadays,intelligent driving vehicles is a research hotspot in the fields of automobiles and computer science.Among them,the research on vehicle emergency avoidance algorithms is a difficult problem to overcome.When the vehicle encounters dangerous driving conditions,the driver usually adopts emergency braking or emergency steering to avoid a collision.This paper studies the vehicle’s emergency braking and emergency steering collision avoidance algorithms based on the scenario of vehicles encountering dangerous driving conditions.Firstly,the structure of the vehicle’s emergency collision avoidance algorithm was determined by studying domestic and foreign literatures.The three aspects of environmental were introduced,surrounding awareness,decision planning,and control implementation.And then,the functions and design ideas of each module were defined.The decision judgment logic of the vehicle’s emergency collision avoidance algorithm is mainly designed,and the shortest collision avoidance distance model based on the characteristics of the vehicle and the adhesion coefficient of the road surface is studied.For the emergency braking collision,the vehicle deceleration,the longitudinal collision avoidance distance,and the road adhesion coefficient are combined while considering the comfort of the driver and passenger to restrain the braking deceleration.For the emergency steering collision avoidance,a polynomial-based simulation is designed.Combined collision avoidance trajectory planning algorithm,the vehicle speed,acceleration,and heading angle are restrained during the collision avoidance process to ensure the stability of the vehicle during the steering avoidance process.Secondly,based on the experimental vehicle’s dynamics model,we built a vehicle emergency collision avoidance algorithm model.In this study,taking into account the need for follow-up tests to verify the real vehicle,and associated control algorithms for the accuracy of the vehicle model has certain requirements,so the study by consulting the relevant data models using MATLAB/CarSim co-simulation platform for the experimental vehicle model parameters matching calibration.Then,we built a vehicle emergency braking model and an emergency steering model,based on the tire magic formula tire model nonlinear structures.Subsequently,this paper uses a hierarchical control architecture to design the vehicle’s emergency collision avoidance control algorithm.A feedback controller(PID)is designed for the vehicle’s emergency braking collision avoidance control algorithm to implement the tracking control of the desired braking deceleration.Aiming at the emergency steering collision avoidance control algorithm,a three-degree-of-freedom vehicle dynamics model is constructed for the subsequent control algorithm based on the obtained vehicle parameters and tire model.After comparing Linear-Quadratic Regulator(LQR)and model predictive controller(MPC),this paper selects MPC as the collision avoidance trajectory tracking control algorithm.Finally,this paper introduces the simulation test environment and experimental vehicles,and proposes an algorithm verification architecture.The vehicle’s emergency collision avoidance algorithm is simulated and tested in a real vehicle.Through the test of the emergency braking controller,we found that its control algorithm responds quickly to the vehicle’s expected braking deceleration,has high control accuracy,and can adapt to a variety of low speed driving conditions.Considering the applicable working conditions of emergency steering avoidance and the safety of actual vehicle tests,this study verified vehicle emergency steering avoidance control algorithms at medium and high speeds.Through analysis of the results,we found that the model predictive control algorithm had better Tracking effect of the collision avoidance track,and there is almost no overshoot and vibration,and it converges fast.While achieving the emergency steering collision avoidance function,it also ensures the stability of the vehicle and improves the comfort of the driver and passengers.