Study On Pedestrian And Vehicle Collision Avoidance Based On The Longitudinal And Lateral Control Of No Signal Road

With the increase of the number of vehicles,the driving environment becomes more and more complex,which puts forward higher requirements for drivers and vehicle active safety system.As a vulnerable group of road users,pedestrians are one of the objects that should be considered to avoid collisions in the vehicle active safety system.Although on roads with traffic lights or crosswalks,the traffic is orderly,but in the absence of light without pedestrian guidance,do not drive civilization and crossing behavior happens quite often,especially pedestrians do not obey the traffic rules violations across the street,leads to the situation of the collision.Pedestrians are a group with subjective consciousness,their behavior has a motion uncertainty,crossing the street that will lead to a higher risk of collision.Therefore,in view of the frequent occurrence of pedestrian and vehicle collision avoidance on no signal roads and considering the uncertainty of pedestrian movement direction,this paper studies the collision avoidance problem by adopting vehicle braking,steering and acceleration strategies,aiming to improve the success rate of collision avoidance and reduce traffic accidents on no signal roads,mainly including the following work:(1)Vehicle hazard assessment and collision avoidance method selection.Aiming at vehicle risk assessment when pedestrians cross the street illegally,dynamic pedestrians are taken as collision avoidance objects,pedestrian income function is constructed to determine the direction of the pedestrian crossing,and pedestrian position prediction model is established to calculate the position of the pedestrian in the future.Assess vehicle risk by calculating the time it takes for pedestrians and vehicles to enter and leave the conflict zone.Then,based on the motion state of the two,the success rate of each collision avoidance method was calculated.Taking the success rate of collision avoidance and the habit of most drivers as the comprehensive judgment principle,the appropriate collision avoidance method was selected for the vehicle to improve the success rate of collision avoidance(2)Research on vehicle longitudinal collision avoidance strategy.According to the situation that the vehicle chooses the longitudinal collision avoidance method,the speed and acceleration range of the vehicle are obtained based on the time requirement that it needs to achieve.Within this range,the component function of each vehicle’s acceleration is constructed,the optimal acceleration is selected by using genetic algorithm,and the expected acceleration is tracked by PI controller,so that the vehicle can successfully avoid collision by controlling the longitudinal velocity.(3)Collision avoidance path planning with improved artificial potential field method.According to vehicle steering collision avoidance path planning problem,considering the relative position of the pedestrians and vehicles,with the improved artificial potential field method of vehicle collision avoidance path planning and verification,is put forward based on the longitudinal and transverse collision avoidance a safe distance from the long axis of the oval adaptive change of improved artificial potential field,to meet the needs of dynamic random changes in behavior when pedestrians as the object of collision avoidance of collision avoidance path planning requirements.The simulation results show that,compared with the artificial potential field before improvement,the improved artificial potential field can calculate the size of the long axis of the obstacle ellipse in real time,and plan the collision avoidance path for the vehicle,and the planned path is smoother and more practical.(4)Vehicle tracking control based on planned path.Taking the planned path of the improved artificial potential field method as the target path,the vehicle dynamics model and the preview deviation model were established to calculate the vehicle position and heading angle deviation at the preview point.In order to ensure the convergence of the system and avoid the singularity of the system,the non-singular terminal sliding mode method is used to control the vehicle path tracking performance.Through joint Car Sim and Simulink simulation experiment,the results show that the nonsingular terminal sliding mode control method can ensure the vehicle stability under the premise of controlling the vehicle’s path compared with the traditional sliding mode control method,the pedestrian crossing direction for 30 collision avoidance scenarios,vehicle lateral displacement deviation and centroid side-slip angle mean reduce 36.54% and 11.11% respectively.