Research on Stiffness Estimation Method Using Micro-Macro Bilateral Control

In recent years, stiffness measurement of micro-order objects is required. For example, analysis of mechanical properties of a new material, such as soft crystal has been attracting attention. In the conventional methods to measure the stiffness, the grasping the object is performed without the force feedback. Therefore, there is a possibility to damage the objects. To solve this problem, this paper proposes stiffness measurement method based on micro-macro bilateral control for micro-order objects. Micro-macro bilateral system consists of the leader system that is easy for the operator to manipulate, and the follower system that is sized to operate in a small environment. For the precise measurement, grasping the object is achieved by the micro-macro bilateral control. In this grasping, the total stiffness including the object and the follower system is measured in real-time. The stiffness of the follower system is identified by the preliminary experiment. As a result, the stiffness of the object is estimated by subtracting total stiffness from the identified stiffness of the follower system. The validity of the proposed method was confirmed from the experimental results.