Towards Time-Optimal Trajectory Planning for Pick-and-Transport Operation with a Mobile Manipulator
Shantanu Thakar, Liwei Fang, Brual C. Shah, Satyandra K. Gupta · 2018
Warehouses and factories are beginning to deploy mobile manipulators for transporting parts between machines and work stations. Minimizing the number of these robots on the shop floor requires that each robot should complete the assigned task in a time-optimal manner and therefore maximize the robot's capacity. In this paper we present a search-based algorithm for generating time-optimal trajectories for picking and transporting parts using a mobile manipulator. The approach is based on a hierarchical search that uses discrete search for planning of the mobile base. The time cost due to the motion of the manipulator for picking up the part is evaluated and integrated with the search state space at the appropriate times. The trajectories generated result in picking up of the part with the manipulator while the mobile base is in motion. The performance of the algorithm is studied for different factory sizes and obstacle densities. This approach enables the mobile manipulator to perform pick and transport operation in a smaller time duration compared to the operation where it stops to pick up the object.