Research On Obstacle Avoidance Control System Based On Active Steering By Wire Function

With the rapid development of intelligent vehicle technology,the realization of driverless vehicle gradually becomes possible.At the same time,with the increasing quantity of vehicles,the number of casualties caused by traffic accidents in our country is high every year,research on intelligent vehicle to improve the driving safety has become one of the ways to solve the problem above.According to the theory of steering by wire system,vehicle dynamics,trajectory planning and trajectory tracking control,the paper put forward the research on obstacle avoidance of intelligent vehicle based on the active steering by wire.The steering by wire system cancels the connection between steering wheel and steering gear,which opens up the development space for front wheel steering control.The intelligent vehicle with steering by wire system is modeled.After the obstacle is detected,it is necessary to plan a track to avoid the obstacle,a new method of obstacle avoidance trajectory planning is proposed.After collecting the state information of obstacles,a state lattice obstacle avoidance environment model is established.Combined with the cost calculation of the state lattice and the search algorithm,the trajectory selection is carried out.This method can comprehensively consider the motion state of obstacles,and can accurately select the optimal trajectory for the scene of multiple obstacles.In order to verify the effectiveness of the proposed method,the simulation under different scenarios is carried out,and the proposed strategy is compared with the traditional grid method to prove the advantages.Considering the nonlinear characteristics of the vehicle model,the influence of parameter perturbation and external disturbance,in the aspect of trajectory tracking,the tracking control strategy of obstacle avoidance based on inner loop angle tracking control and outer loop improved active disturbance rejection control is proposed.The influence of disturbance factors on trajectory tracking is considered on the basis of controlling the angle,the ideal yaw angular velocity compensation is used as the target of outer loop control.Aiming at the disadvantage of many parameters of active disturbance rejection control,the improvement to active disturbance rejection control is put forward,and the effectiveness of the control strategy is verified by simulation.The hardware-in-loop test platform of active steering by wire system based on Carsim and PXI is set up,and the test is carried out under the same conditions as the simulation.In addition,the designed active steering system is loaded into a vehicle,and the feasibility of the obstacle avoidance control system based on the active steering by wire system proposed in this paper is proved.