Flexible, wideband triboelectric accelerometer integrated into quadruped robot legs for vibration source detection and localization

Robots play a vital role in vibration detection and localization, particularly in industrial pipeline health monitoring and machinery fault diagnosis. Inspired by the biological ability of animals to perceive vibrations through their limbs, the integration of sensors into robotic legs significantly enhances environmental perception capabilities. However, the design of such sensors involves considerable technical challenges due to the limited space and uneven surfaces of robotic legs, necessitating miniaturization, flexibility, durability, and a wide frequency response range. Addressing these challenges, this study presents a flexible accelerometer integrated into robotic legs for effective vibration sensing in complex environments. The proposed ultra-thin grid-like sensor (UGS), with a thickness of only 0.5 mm, is based on triboelectric nanogenerator principles. It is fabricated using copper and polytetrafluoroethylene powders with optimized particle size combinations, enhancing the contact area and improving output performance. The UGS demonstrates exceptional flexibility, a broad frequency detection range (8 Hz–6 kHz), high sensitivity (0.49584 mV/(m/s²)), and remarkable durability, maintaining performance over 35,000 cycles. It effectively detects environmental vibrations as well as signals generated by the robot's movements. Coupled with a time difference of arrival-based localization algorithm, the sensor supports multi-scenario vibration source localization experiments in environments, achieving average angular and distance accuracies of 97.72 % and 95.26 %, respectively. This study highlights the potential applications of the UGS in pipeline leakage detection, machinery fault diagnosis, and structural vibration monitoring, offering innovative solutions for robotic environmental sensing.