An Optimal Path-planning Algorithm for Unmanned Rollers with Constraints on Roller Attitude

Abstract

The unmanned roller (UR) is promising in improving the compaction quality and efficiency simultaneously. When transiting from on work site to another, a well-designed path-planning algorithm is essential for the efficient operation of rollers between two sites. Existing path planning algorithms barely consider the vehicle attitude at the destination and the kinematic constraints, limiting the efficiency in the initial phase of operation in a new work site. Therefore, in this paper, an improved RRT* algorithm is proposed. By combining Dubins curve with RRT* algorithm, the algorithm enforces the roller to maintain an optimal attitude (orientation) when approaching the entrance of the next work site, by manipulating the target path. In addition, a smooth and achievable path is generated, by setting-up the upper bound of the curvature based on kinematic and steering dynamic models then fitting the target path using the B-spline. The proposed algorithm is tested in both simulation and experiments, confirming its effectiveness.