Load Sharing in Distributed Collaborative Manipulation

The letter considers the multi-robot collaborative manipulation with load sharing characteristic, when dynamic parameters of the system composed of multiple robots and the rigid body are unknown. Load sharing refers to each robot calculating the required wrench for the manipulation task itself and actively sharing the manipulation duty when the global grasp matrix and system parameters are unknown. The global information however must be collected for the load distribution algorithm in the literature, where a central node is required for the distribution calculation. On the contrary, we propose a distributed control framework based on the idea of the weighted consensus and the parameter estimation to achieve the load sharing among robots according to the prescribed contribution factor, when only the local grasp matrix is needed. It is found that the manipulation wrench provided by the proposed controller causes no squeezing effect on the object at the steady state. The numerical simulation and real-robot experiments verify the effectiveness of the proposed framework.