Human Robot Hand Interaction with Plastic Deformation Control

Abstract

In recent years, force control has become more important due to the physical interaction of robots with humans and applications of robots to complex environments. Impedance control is widely used in force control; however, it cannot reproduce the behavior of plastic deformation because it returns to the initial position when the force is removed, similar to elastic deformation. On the other hand, Senoo et al. have proposed plastic deformation control based on the Maxwell model. However, because plastic deformation control is model-based, it is subject to the modeling and parameter errors of the controlled system. A robot hand is relatively small and lightweight; because it uses a gearbox with a high reduction ratio for its joints, it is significantly affected by friction and tends to deviate strongly from the desired motion. Therefore, in this study, a method that is robust against modeling and parameter errors is proposed by feeding back the error from the desired trajectory with the inner position loop. Then, the effectiveness of the proposed method is shown through simulations and experiments using an actual robotic system.