Research on path planning method of an unmanned vehicle in urban road environments

Abstract

Path planning is one of the crucial technologies for autonomous driving of unmanned vehicle. It is considerably difficult for unmanned vehicles to perform a path planning assignment in an urban environment due to the complexity of the environmental constraints. In order to solve this problem, a new path planning method is introduced in this paper. We did not regard the unmanned vehicle as a particle, but selected the front-wheel-drive model combined with the mechanical constrains to calculate the path of the vehicle. The constraints of the external environment and mechanical limitations are introduced into different objective functions. This paper also proposes an algorithm based integration of the A* and Stochastic Fractal Search (SFS) algorithms. The integrated algorithm searches for the optimal path, which is the shortest path to the target location of the vehicle’s rear axle mid-point in the raster map, with the help of the A* algorithm. Then, based on the shortest path the SFS algorithm generates the vehicle path, which contains the vehicle status information. Finally, the A* and SFS algorithms are compared under the same simulation environment when searching for a path of the vehicle’s rear suspension. The results simulated on MATLAB R2012a show that the composite method we propose is effective in solving the path planning problem in an urban environment.