High-Stiffness and High-Sensitivity 3-Axis Force Sensor Using Strain-Deformation Expansion Mechanism

For dexterously performing object grasping and manipulation with multifingered hand of robot, sensing the fingertip forces with high-stiffness and high-sensitivity is desired. In general, from previous sensing structures, if the stiffness of a sensor is made be higher, its sensitivity is reduced. This paper proposes a novel mechanism called strain-deformation expansion mechanism for 3-axis force sensing. By the force sensing mechanism, the small strain-deformation used for force sensing can be expanded while the sensor stiffness is not reduced but is heightened. In this paper, the force sensing principle is addressed by analyzing the deformation of the sensing mechanism and the forces acting on the sensor theoretically. Then, the sensitivity of the sensing mechanism and its expansion rate of sensitivity are defined, and a design method for realizing the sensing mechanism with high sensitivity is discussed. Lastly, some experiments are performed to show the basic characteristics and the effectiveness of the sensing mechanism