Research on Stiffness Estimation Method Using Micro-Macro Bilateral Control

In recent years, stiffness measurements of micro-order objects are required. For example, analysis of the mechanical properties of a new material, such as a soft crystal, has been attracting attention. In the conventional methods to measure the stiffness, the grasping object is held without force feedback. Therefore, there is a possibility of damaging the objects. To solve this problem, this paper proposes a stiffness measurement method based on micro-macro bilateral control for micro-order objects. The 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 the total stiffness from the identified stiffness of the follower system. The validity of the proposed method was confirmed by the experimental results.