Hybrid motion reproduction using master/slave type motion-copying system

This paper proposes a hybrid motion reproduction structure using a master-slave structure manipulator based on a motion-copying system. Data-driven control will be an important technique in the near future. Learning from Demonstration (LfD) using a robot manipulator is already used in manufacturing. Unlike other motion observation methods based on visual or trajectory responses, a motion-copying system can obtain not only trajectory response but also force response during contact motion, which is necessary to realize contact tasks. A motion-copying system has two phases, the motion saving phase and motion reproduction phase. In the motion reproduction phase, the motion stored in the motion saving phase obtained from the bilateral control can be used to reproduce specific motion. Existing control methods for a motion-copying system have only one system in the reproduction phase, a slave system. It is necessary to consider the case where there are two systems in the phase to widen the application of a motion-copying system. The additional system can provide flexibility to the reproduced motion. In this case, data, human, and a robot are involved in reproducing the motion. In this paper, the control structure is proposed when there are two systems in the motion reproduction phase. Because there are two systems, it is necessary to design the controllers for each system. The proposed method uses a coordinate transformation technique to design two motions in each system separately. The paper also introduces a novel index called the reproduction ratio. It determines the motion to be reproduced in the motion reproduction phase. The ratio is used as an element of a coordinate transformation matrix. The experimental results show the validity of the proposed method.