An Optimal Trajectory Planning for Autonomous Vehicles Based on Vehicle Dynamics Constraints

Abstract

In order to improve the safety and comfort of the unmanned vehicle, an optimal local trajectory planning algorithm based on the constraints of vehicle dynamics equation is proposed in this paper, which can also conveniently satisfy the constraints at the starting and end point of the trajectory. In order to prove the superiority of this algorithm, this paper compares it with another two commonly used trajectories described by trigonometric and polynomial function between the same starting and end point, and contrastive analysis of the tracking deviation under a same control strategy. The tracking results show that zero error tracking can be achieved for the optimal trajectory because the optimal trajectory and corresponding steering angle are obtained at the same time in our algorithm and the vehicle dynamic constraints also have been taken into consideration. The polynomial path tracking error is the largest and the trigonometric path is moderate comparatively. In the whole tracking process, the optimal path proposed in this paper can obtain the minimum input absolute value and energy value of the steering angle while the vehicle's side angle, heading angle and yaw rate are relatively small, so that the safety and comfort of the vehicle are ensured.