Self‐Powered Underwater Pressing and Position Sensing and Autonomous Object Grasping with a Porous Thermoplastic Polyurethane Film Sensor

Abstract Most flexible ionic tactile sensors can hardly be used in deep sea due to their poor antiswelling and anticompression properties under high hydrostatic pressure. To achieve pressure and position sensing under high hydrostatic pressure, a self‐powered underwater tactile sensor made of a porous thermoplastic polyurethane (TPU) film is presented in this paper. The sensor works by generating an electric current due to the different moving velocities of ions in the porous film under pressing. Experimental results show that the magnitude of the generated current signal increases with the applied pressure, the contacting area, and ion concentration of the solution. The direction and magnitude of the current signal depend on the pressing position of the film. The signal magnitude decreased with the closer to the center of the film. The maximum pressure sensitivity and positioning resolution are 0.62 kPa⁻¹ and 1.31 mm respectively. Response time (0.19 s), 0.67 s recovery time, and 50–600 kPa pressure detection range are achieved. In addition, the signal magnitude is decreased only by 15.53% when the sensor is placed underwater at a simulated depth of 100 m. Proof of concept demonstration of underwater autonomously grasping objects of different weights with this sensor is successfully achieved.