Research On Path Planning And Obstacle Avoidance Method For Vehicle Based On Improved Artificial Potential Field

With the increasing number of vehicle in China,the road traffic safety situation is becoming increasingly serious,especially the collision accident,so more and more people play more attention on traffic safety.But the current passive safety technology such as airbags and seat belts can not meet people's need.Therefore,the manufacturers have developed varieties of pre-crash safety systems,such as Mercedes-Benz's pre-safe system and Volvo's CWAB(Collision Warning with Brake Support).These systems can only reduce the degree of collision's damage through reducing the vehicle's speed,but the accident can not be avoided.The obstacle avoidance path planning technology,which is based on active safety,can guide the vehicle to avoid obstacles,and this technology is helpful to improve the road traffic safety.This paper first analyzes and summarizes the current research situation of obstacle avoidance path planning from domestic and abroad,and summarizes the methods of global path planning and local path planning.It is found that the artificial potential field method is widely used in the field of path planning,but this method has local optimal problem.In this paper,by adding the distance between the vehicle and target point in the repulsive field function of the artificial potential field,the value of the repulsive force and attractive force becomes zero only when the vehicle reach the target point,that is to say the target point becomes the minimum point of the potential energy value,thus the local optimal problem and destination unreachable problem are solved.For accurately describe the driving environment and obstacle information using artificial potential field.this paper establishes the road boundary repulsion potential field and the obstacle velocity repulsion potential field based on the traditional artificial potential field.In order to improve the safety and comfort during the obstacle avoidance process,this paper establishes a speed control model,which can make the speed change with the distance between vehicle and obstacle.The simulation results show that the improved artificial potential method not only can plan a safe obstacle avoidance path in the static environment,but also can make the vehiclesafely avoid obstacles in the dynamic environment.In order to control the vehicle to travel along the obstacle avoidance path,this paper establishes the driver feedback correction model based on the lateral acceleration driver model and the prediction-follow theory.By establishing the vehicle dynamics model in Carsim and the driver model in Simulink,we use the Simulink and Carsim joint simulation platform to verify the correctness of the driver model.The results shows that the driver model can control the vehicle accurately track the obstacle avoidance path,and the speed control model can greatly improve ride comfort in the process of obstacle avoidance.Finally,this paper designs a obstacle avoidance traffic environment based on the driving simulator to further verify the correctness of the obstacle avoidance path.the results of the test show that the obstacle avoidance path planned by the improved artificial potential field method is almost the same as the driver's obstacle avoidance path,and then the test verifies the correctness of the method.