Miniature 6-axis force/torque sensor for force feedback in robot-assisted minimally invasive surgery

In order to restore force sensation to robot-assisted minimally invasive surgery (RMIS), design and performance evaluation of a miniature 6-axis force/torque sensor for force feedback is presented. Based on the resistive sensing method, a flexural-hinged Stewart platform is designed as the flexible structure, and a straightforward optimization method considering the force and sensitivity isotropy of the sensor is proposed to determine geometric parameters which are best suited for the given external loads. The accuracy of this method is preliminarily discussed by finite element methods (FEMs). The sensor prototype is fabricated with the development of the electronic system. Calibration and dynamic loading tests for this sensor prototype are carried out. The working ranges of this sensor prototype are 30 N and 300 N center dot mm, and resolutions are 0.08 N in radial directions, 0.25 N in axial direction, and 2.4 N center dot mm in rotational directions. It also exhibits a good capability for a typical dynamic force sensing at a frequency close to the normal heart rate of an adult. The sensor is compatible with surgical instruments for force feedback in RMIS.