Whole-body control on non-holonomic mobile manipulation for grapevine winter pruning automation

Mobile manipulators that combine manipulability and mobility, are increasingly being used for various unstructured application scenarios in the field, e.g. vineyards. Therefore, coordinated motion of the manipulator and mobile base is an essential feature of the overall performance. In this paper, we explore a whole-body coordinated motion controller of a robot which is composed of a 2-DoFs nonholonomic wheeled mobile base with a 7-DoFs manipulator (non-holonomic wheeled mobile manipulator, NWMM). This robotic platform is designed to efficiently undertake complex grapevine pruning automation. In this control framework, a task priority coordinated motion of the NWMM is guaranteed. Tasks with lower priority are projected into the null space of the top-priority tasks so that higher-priority tasks are completed without interruption from lower-priority tasks. The proposed controller was evaluated in a grapevine spur pruning experiment scenario.