Optical and electrical dual-mode tactile sensor with interlinked interfaces recording normal force and slip for closed-loop robotics

The rapid development of electronic skin will allow disabled people and intelligent robots to interact more effectively with their surroundings. Nevertheless, it remains challenging to simultaneously capture multi-dimensional personalized information (including pressure and slip sensation) through simple device structure design with high stability under complex mechanical conditions. Here, a tactile sensor with simple structure and reliable performance (withstand considerable stretching, twisting, bending, and vibration) is designed for pressure and slip sensing. It is implemented by optical and electrical dual-mode sensing mechanisms and high toughness interlinked interface strategy (interfacial toughness similar to 33.69 Jmy(-2), nearly 5 times higher than control sample). This device is composed of a periodic microstructured piezoresistive layer and a triboelectrification-induced electroluminescent (TIEL) layer, both of which are based on the quasi-homogeneous PDMS (poly-dimethylsiloxane) composite. The whole device possesses the characteristics of lightness, flexibility, and light-transmitting. Besides, the device could automatically locate and track the slip motion while detecting the normal pressure in a large range (0-1,000 kPa). As an application demonstration, the sensor is installed on a flexible manipulator and combined with the closed-loop control system. Compared to a single electrical mode, the optical and electrical dual-mode tactile sensor could more accurately monitor the sliding of the clamped object, adjust the clamping force instantly, and avoid object slipping. The unique performance of the device shows great potential in trajectory recognition, artificial limbs, intelligent robots, and human-machine interfaces.