Planning for Multi-stage Forceful Manipulation
This work is significant for robotics researchers and practitioners dealing with complex forceful manipulation tasks, providing a system that can plan and execute such tasks by explicitly considering force requirements.
This paper addresses multi-stage forceful manipulation tasks, where robots must reason about discrete and continuous choices under force constraints. The authors augment a task and motion planner with wrench-exerting controllers and explicit torque/frictional limits. They demonstrate the system's ability to consider combinatorial strategies and the impact of robust action choices on strategy in opening a childproof bottle and twisting a nut.
Multi-stage forceful manipulation tasks, such as twisting a nut on a bolt, require reasoning over interlocking constraints over discrete as well as continuous choices. The robot must choose a sequence of discrete actions, or strategy, such as whether to pick up an object, and the continuous parameters of each of those actions, such as how to grasp the object. In forceful manipulation tasks, the force requirements substantially impact the choices of both strategy and parameters. To enable planning and executing forceful manipulation, we augment an existing task and motion planner with controllers that exert wrenches and constraints that explicitly consider torque and frictional limits. In two domains, opening a childproof bottle and twisting a nut, we demonstrate how the system considers a combinatorial number of strategies and how choosing actions that are robust to parameter variations impacts the choice of strategy.