Real-Time Collision-Free Motion Planning and Control for Mobile Manipulation with Quadrupeds
Zhefeng Cao, Hua Chen, Sen Li, Wei Zhang · 2023
In this paper, we study the mobile manipulation problem with a quadruped-arm system in cluttered enviornment. To address this problem systematically, we propose a real-time collision-free motion planning and control framework that distributes the collision avoidance task into multiple layers. In details, we decompose the overall legged mobile manipulator system into a quadruped subsystem and an arm subsystem, plan the collision-free trajectories for the base and the end-effector while respecting their inherent kinematic constraint. Then with the guidance of the base and end-effector trajectories, we can find feasible velocity commands for the quadruped and the arm respectively by solving a quadratic programming problem with the collision-free constraint to guarantee safety of the whole body system. After getting the velocity commands for the quadruped, we further synthesize a customized model predicitve controller to track the given reference while incorporating the effect of the moving arm. The framework is validated by the navigation and manipulation tasks in simulation with a real legged-mobile manipulator system. In the experiments, the average computation time for our motion planner is 76 ms and the planned trajectory is smoother and faster than the existing motion planners. Simultaneously, the collision avoidance requirement can be obeyed during the whole process.