A Thin Plate Type Tactile Sensor Using a Piezoelectric Polymer

Abstract

We developed a prototype thin plate type tactile sensor for detecting surface shapes such as micro-step shapes and rough shapes.A piezoelectric polymer (polyvinylidene fluoride; PVDF), which has stress (strain) rate dependent output, is glued on the thin plate.Therefore, when the tip of this thin plate scans target uneven surfaces, sharp changes on the surfaces are easily sensed.In this study, we showed that this simple sensing system experimentally detects a single micro-step shape clearly up to a scanning speed of 20 [mm/s], which is higher than that of the popular stylus type surface roughness tester.The characteristics of the experimental output signals agree with the estimated signals.Moreover, we showed that this tactile sensor can detect different triangle wave-shape surface roughness (arithmetic average roughness Ra: 1.6-6.3[µm]) limited to a low scanning speed; this subtle shape detection was impossible by using a strain gauge as the sensor element instead of PVDF.