Characterization of Large-Area Pressure-Sensitive Robot Skin

Sensorized robot skin has considerable promise to enhance robots' tactile perception of surrounding environments. For physical human-robot interaction ( pHRI) or autonomous manipulation, a high spatial sensor density is required, typically driven by the skin location on the robot. In this study, two flexible sensor arrays with different densities (i.e., 4x4 and 11x11 skin arrays) are printed and packaged onto Kapton sheets and silicone encapsulants. To address scalability, sensitivity, and calibration challenges, a novel electronic module, free of the traditional signal conditioning circuitry was created. The electronic design relies on a software-based calibration scheme using high-resolution analog-to-digital converters with internal programmable gain amplifiers. In this paper, we show the efficacy of the proposed method with the 4x4 skin array using controlled pressure tests, and then perform procedures to evaluate each sensor's characteristics such as dynamic force-to-strain property, repeatability, and signal-to-noise-ratio. In order to handle larger sensor surfaces, an automated force-controlled test cycle was carried out. Results demonstrate that our approach leads to reliable and efficient methods for extracting tactile models for use in future interaction with collaborative robots.