The tactile sensors using polymer have been studied in various robot fields, especially robot fingertip and MIS, which are required feedback on the contact force because the polymer is flexible and affordable. The tactile sensors are fabricated using various polymer; PDMS, NBR, PI, PU, PET etc. We fabricate mainly the film-type flexible tactile sensor. MEMS process is utilized to fabricate the tactile sensor which is required very small pattern spacing.
The principle of the capacitive force sensor using polymer is as follows; capacitance values are changed by changes in the thickness of the dielectric under normal force or changes in the overlapping area of electrodes under shear force. The force and moment are measured by such changes.
Conventional one-axis capacitive type force sensors measure normal or tangential force from one pair of electrodes. The increased number of electrodes can be used for multi-axis force sensors at the cost of complexity of wiring and the size of the sensor. Therefore, recently, the main issue is the hybrid type sensor in the lab. Hybrid type sensor (the capacitive type sensor + the resistive type sensor) using polymer can measure the dual-axis force with only a pair of electrodes.