Flexible wide-range, sensitive three-axis pressure sensor array for robotic grasping feedback

摘要

• Three-dimensional capacitive tactile sensing system for measuring mechanical stimuli was proposed and developed including a flexible tactile sensing array based on a 4 × 2 three-dimensional sensing unit with a sandwich structure and a circuit for simultaneous acquisition of 6 sensor arrays (240 channels of data). • The fabrication process of the flexible sensor array is straightforward, adopting sandwich structure: a flexible printed circuit with polyimide (PI) as the electrode substrate, PDMS with the hollow structure as the intermediate medium layer, and a three-dimensional force conduction block. The sensor array has high sensitivity, fast response time and large measurement range. • Test results demonstrate its capability to detect normal forces ranging from 0-46 N (0-520 kPa) with a sensitivity of 0.442 N −1 (0.031 kPa −1 ) and tangential forces from 0-10 N with a sensitivity of 0.08 N −1 (X-axis) and 0.07 N −1 (Y-axis). • The manipulator grasping system is designed to enable real-time measurement of the manipulator grasping a target and enhance the stability of robotic manipulation. Flexible pressure sensors capable of detecting normal and tangential forces through physical contact have garnered considerable interest in the realm of human-interactive systems. However, simultaneous detection of multi-directional forces is still a challenge for current research. Herein, a capacitive flexible pressure sensor based on a sandwich structure for three-dimensional force detection is proposed. The fabrication process of the sensor array is straightforward, capable of effectively distinguishing between normal and tangential forces. Polyimide (PI) serves as the flexible substrate for depositing the metal electrode pattern, while Polydimethylsiloxane (PDMS) acts as the intermediate dielectric layer material and the three-dimensional force conduction block. Through a comparative study of the thickness of the hollow dielectric layer, a pressure sensor with superior performance was prepared, featuring high sensitivity across a wide working range. Test results demonstrate its capability to detect normal forces ranging from 0-46 N (0-520 kPa) with a sensitivity of 0.442 N −1 (0.031 kPa −1 ) and tangential forces from 0-10 N with a sensitivity of 0.08 N −1 (X-axis) and 0.07 N −1 (Y-axis). The designed acquisition system can simultaneously gather data from 6 sensor arrays, totaling 240 channels, with a response time of 11ms. This sensor array, characterized by flexibility, versatility, and a wide range, is suitable for applications in robot tactile perception.