Development of 4-DOF Soft-Contact Tactile Sensor and Application to Gripping Operation of Robotics Fingers

This paper describes the development and application of a 4-DOF (degree of freedom) soft-contact tactile (SCT) sensor that uses 6-DOF micro force moment sensing (MFMS) chip. The 6-DOF MFMS chip is working based on the piezoresistive effect in single crystal silicon. The SCT sensor can independently detect three components of force (Fx', Fy', Fz') and one components of moment (Mz'). The MFMS chip and the SCT sensor have been calibrated. The calibrated sensitivities to Fx, Fy, Fz, Mx, My and Mz components are SFx =0.06(mV/mN), SFy =0.054(mV/mN), SFz = 0.136 (mV/mN), SMx = 1.449 (mV/Nmum), SMy = 1.451(mV/Nmum), and SMz = 0.751(mV/Nmum), respectively, (bias voltage Vin = 2 V). The sensitivities of the SCT sensor to the forces Fz', Fx' (or Fy') and moment Mz' are 0.085 (mV/mN), 0.039 (mV/mN) and 0.004 (mV/Nmum), respectively. The outputs were linear and the crosstalk was small. The sensor has been mounted onto robot fingers to sense the forces from gripping operation.