A triboelectric multifunctional sensor based on the controlled buckling structure for motion monitoring and bionic tactile of soft robots

Soft robots have unlimited degrees of freedom, which limits the application of traditional sensors in the field of soft robots. Therefore, continuous motion monitoring and tactile feedback for soft robots have been challenging. To address this challenge, this paper proposes a multifunctional sensor by combining a controlled buckling structure with triboelectric nanogenerator for the first time to detect and control grasping, realize two-dimensional (2D) planar motion, and achieve adaptive obstacle avoidance in soft robots. A 2D kirigami electrode is compressed and buckled into a stretchable three-dimensional (3D) structure by pre-stretching the substrate. The proposed soft grasping system sensor can detect the bending angle of a soft gripper to identify the size of a grasped object, achieving a detection accuracy of 91.67 %. By alternately arranging the buckling electrodes to form a 2D spatial decoupling structure, the 2D motion sensor (2DMS) can detect the movement direction and real-time position of a robot with an accuracy rate of 83.33 %. Using the compressible properties of the buckling 3D structure, the inchworm-like soft robot (I-LSR) tactile sensor can sense the surrounding environment, thereby realizing dynamic obstacle avoidance. The proposed novel multifunctional triboelectric sensor by combining the properties of controlled buckling structure provides a theoretical and experimental basis for high-precision motion detection and intelligent obstacle avoidance for soft robots.