In-Hand Manipulation Using Interaction Mode Control in Polar Coordinate System

Due to a declining population, Robots are expected to become reliable partners for humans in the near future. Such robots need to have the ability to manipulate objects dexterously in their hands. This paper proposes an in-hand manipulation method using modal control for realizing advanced tasks with tendon-driven robots. Using interaction mode control, position and force control can be switched in a unified manner. Therefore, it is possible to intuitively design a control system for when robots have contact with an object and when they do not. The proposed method uses a polar coordinate transformation to simply describe the translation, rotation, and grasping. Some experiments showed that not only a simple task such as the rotation of three objects with different stiffnesses, masses, and shapes, but also advanced tasks such as opening a cap can be realized using the proposed method. As a result, we demonstrated that the interaction mode control can be handled in the polar coordinate system and that the interaction mode control is effective for realizing dexterous object manipulation.