Mass estimation in microgravity with a variable stiffness mechanism

A new method to estimate the mass of an object in microgravity is proposed in this paper. The proposed method uses a new mechanism that consists of a variable stiffness mechanism and an actuator. A sample is attached at the tip of a blade spring in the variable stiffness mechanism, which controls an effective length of the blade spring to adjust the stiffness. An actuator swings the mechanism periodically and satisfies the anti-resonance condition. Then, the mass of an object is estimated with the period of the swing and the length of the blade spring in the anti-resonance mode. The controller requires no system parameters to adjust the stiffness. Simulations and experiments are executed to verify the effectiveness of the proposed method.