Vehicle-manipulator motion planning method for Chat-PM in near-obstacle environments

To address the motion planning problem of the hybrid aerial/terrestrial manipulator in an environment with nearby obstacles, this paper proposes a planning framework that integrates hierarchical trajectory optimization and manipulator disturbance suppression. Firstly, to address the limitation of conventional mobile robot planning methods that do not distinguish the geometric features of obstacles, a hierarchical collision penalty mechanism is designed based on the B-spline trajectory parameterization method: by differentiating between planar obstacles and unstructured obstacles, trajectories that fit the surface of planar obstacles are generated, and the support effect is utilized to enhance the stability of the robot's motion; strict obstacle avoidance constraints are imposed on unstructured obstacles to ensure the safety of the trajectory. Secondly, to reduce the dynamic disturbance of the manipulator's motion on the body, a nonlinear model predictive control (NMPC) framework is constructed, which comprehensively considers the joint motion constraints of the manipulator, the tracking accuracy of the end effector, and the minimization of disturbance force/torque in the multi-objective cost function, and optimizes the manipulator's trajectory in real-time through rolling optimization to achieve collision-free, smooth, and low-disturbance planned motion. Finally, the motion planning of Chat-PM and the manipulator is verified on the ROS Rviz visualization platform and the Gazebo physical simulation platform. The experimental results demonstrate the effectiveness of the proposed method.