Research On Trajectory Planning And Control Method Of Emergency Lane Change For Intelligent Vehicles

With the rapid integration of automotive industries and high technology such as new-generation information technology,sensors and intelligent control,intelligent automobile technology has become one of the hotspots in the field of automotive engineering in the world.Vehicle motion planning and control as a key issue for intelligent vehicle technology has directly affected the intelligent vehicle whether it can drive on the road safely,smoothly and quickly,and is being watched by researchers at home and abroad.The existing research on vehicle motion planning and control methods cannot take into account the real-time and adaptive requirements in the case of emergency obstacle avoidance.In order to solve the current existing problems of trajectory planning and tracking control methods for emergency lane change,through the study of the segmented trajectory planning,the optimization method based on hpadaptive pseudospectral and the trajectory tracking control method based on self-antidisturbance,the real time and adaptability of the motion trajectory planning and tracking control method in the case of emergency obstacle avoidance are improved.This paper is mainly divided into three aspects: segmented trajectory planning method,segmented trajectory cohesion and optimization method and trajectory tracking control method,and the effectiveness of the proposed emergency obstacle avoidance trajectory planning and control method was proved through the building of test platform.Firstly,the segmented trajectory planning method was studied.The emergency lane-changing obstacle avoidance process was divided into initial stage and tracking stage,the real road experiment was carried out on the steering condition,real vehicle experiment data of the excellent driver’s steering operation was handled with cluster analysis,fitting the relationship between the steering angle of the wheel in the process of emergency lane change and the time,which is an excellent driver’s emergency lane model,was used as the trajectory of the initial stage.By establishing and solving constraint equations,the sigmoid function expression was required as reference trajectory for tracking stage.Secondly,the segmented trajectory planning and optimization method was studied.The segmented trajectory cohesion and optimization method was proposed based on hp-adaptive pseudospectral method innovatively,the initial stage and tracking stage trajectory were connected and optimized to get the emergency lane-changing avoidance trajectory for satisfying all constraints.The effectiveness of the method and the adaptability of the obstacle avoidance trajectory planning method was verified through the joint simulation experiment.Then,the trajectory tracking control method was studied.In view of the real-time and adaptive requirements of the trajectory tracking control for the emergency obstacle avoidance,an auto-disturbance rejection trajectory tracking controller based on curvature control was established innovatively.The feedforward input was obtained from steady state yawing angular velocity gain,and the feedback compensation was obtained by using the curvature difference between the desired trajectory curvature and the current trajectory curvature,the compound trajectory control of the emergency obstacle avoidance trajectory was performed.The effectiveness of the trajectory tracking technique was verified through simulation experiment.Finally,the test platform which took the intelligent small car as the core was established for proving the segmented trajectory planning algorithm and trajectory tracking control algorithm.The feasibility and effectiveness of the emergency obstacle avoidance trajectory planning and control method proposed in this paper was proved through setting different emergency scenarios.