Fabrication and Characterization of 4-DOF Soft-Contact Tactile Sensor and Application to Robot Fingers

This paper describes the development and application of a 4-DOF (degree of freedom) soft-contact tactile (SCT) sensor using 6-DOF micro force moment sensing (MFMS) chip. The 6-DOF MFMS chip is working based on the piezoresistive effect in single crystalline silicon and has been fabricated and calibrated completely. The MFMS chip has been packaged to produce a 4-DOF soft-contact tactile sensor, which has the contact part made of silicone rubber. The 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/mum), SMy = 1.451(mV/N|im), and SMz = 0.751(mV/N|im), respectively, (bias voltage Vin = 2V). 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/mum), 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