A Highly Sensitive Multimodal Tactile Sensing Module with Planar Structure for Dexterous Manipulation of Robots

Abstract

Herein, a multimodal tactile sensing module that can improve the dexterous manipulation capabilities of robots with parallel grippers is reported. The tactile sensor consists of a 4 × 4 matrix 3-axis force sensor array (with spacings of 2 mm) and a single-temperature sensor. The tactile sensor uses inorganic silicon and gold as materials for the detection of strain and temperature and a polymer-based elastomer to encapsulate the sensing layer. The sensing module is equipped with a readout circuitry for signal processing. Within the measurable force range (≈1.5 N) of the sensor cell, a prototype module exhibits a repeatability error within 2%, a hysteresis error within 3%, and a resolution as small as 10 mN. Furthermore, each sensor cell independently measures 3-axis forces with a cross-talk error of approximately 3%. The temperature sensor exhibits linear output properties in the approximate range of 5–75 °C. Experiments are performed by mounting the module on a parallel gripper to grasp a paper cup and a reflex hammer toy. According to the experimental results, the sensor can accurately detect the state of contact with an object by analyzing three tactile modalities (i.e., 3-axis force distribution, vibration, and temperature).