Research On Safety Strategy Of Intelligent Vehicle Facing Emergency Conditions At Crossroads

When the intelligent vehicle is driving at the intersection in emergency dangerous conditions,the vehicle’s active collision avoidance safety system can control the vehicle to slow down or turn,avoid the occurrence of collision,improve the driver’s driving safety,but also can intervene in the collision to minimize the driver’s collision damage.This paper focuses on longitudinal collision avoidance,transverse collision avoidance,transverse and longitudinal composite collision avoidance,and studies the methods of collision avoidance without timely intervention.The main contents are as follows:(1)According to the requirements of simulation environment and control accuracy,the dangerous conditions of cross driving and the 14 degrees of freedom dynamics model of the vehicle are built.The dynamics model is compared with Carsim’s vehicle dynamics model,and its validity is verified by simulation.It is used as the main controlled model.(2)For longitudinal collision avoidance planning control,a hierarchical control strategy is designed.The upper layer adopts fuzzy control to output the required acceleration of vehicle collision avoidance,and the lower layer adopts PID control to track the acceleration.The effectiveness of the longitudinal collision avoidance control algorithm is verified by simulation.(3)For lateral collision avoidance planning and control,a hierarchical control strategy is designed.The upper layer uses quintic polynomial to simulate the path,and optimizes the safe distance of the path,lateral acceleration of the vehicle and yaw velocity to find the optimal path.The lower layer uses model predictive control MPC to track the path,and limits the control quantity and output quantity.Finally,the effectiveness of the transverse collision avoidance control algorithm is verified by simulation.(4)For horizontal and longitudinal composite collision avoidance planning and control,hierarchical control strategies and decoupling control strategies are designed.The upper layer uses the improved Lattice algorithm to plan S-t curve and L-S curve of optimal trajectory,the lower layer uses double-loop PID control to track S-t curve,and uses MPC control to track L-S curve.Finally,the effectiveness of the composite collision avoidance control algorithm is verified by simulation.(5)For the collision damage minimization planning control,a hierarchical strategy is adopted.Firstly,all collision situations are enumerated to find the collision situation with the minimum collision damage,and its collision point is taken as the tracking target of the lower PID control.Finally,simulation is used to verify the effectiveness of the algorithm.In short,this paper focuses on the safety strategy of intelligent vehicles in emergency and dangerous conditions when they drive at intersections.The goal is to ensure the driving safety of drivers,and a complete set of safety strategy system is constructed,covering collision avoidance and collision avoidance.