Development of a 3-Axis Planer Force/Torque Sensor for Very Small Force/Torque Measurement.

Abstract

In the present paper, we propose an H-slit beam which can be effectively utilized to achieve a highly unidirectional deformable structure.The outlines and characteristics of a 3-axis force / torque sensor based on the above proposal is also reported.This sensor can measure very small reaction forces and torques generated by the motions of a robotic manipulator having its degress of freedom in only one plane.For such an application, a sensor structure which accepts no effect of gravitational force on the manipulator is needed.The important point to consider is that the sensor should be sensitive only in the direction of measurement of force / torque, and very stiff in all other directions.To achieve this goal, we propose the H-slit structure as an extension of the parallel beam structure.The idea behind is the formation of a 4-link closed structure, the joints between the links are deformable, hence the strain gauges can be fixed at these positions.By changing the dimensions of links, a variation in sensitivity and directional stiffness is possible, and by changing the dimensions of H-slit, a mechanical over-load protection is also achieved.