Self-Sensing Soft Pneumatic Micro Actuators for Haptic Feedback and Human-Machine Interfaces

This paper presents a self-sensing soft pneumatic micro actuator based on a liquid metal capacitive sensor, which provides a prospect of realizing more precise and controllable fully flexible haptic interface. The flexible pneumatic actuator is less than 500 μm in radius, close to the haptic spatial resolution of human skin. It features large displacement (about 140 μm), large output force (over 160 mN) and wide frequency bandwidth (at least 60 Hz). A completely soft capacitive sensor is integrated with the actuator for self-sensing capability. Its liquid-metal electrodes can withstand large local strain brought by the actuator. The self-sensing feature is stable and repeatable under continuous stimulus over 500 cycles and exhibits good frequency characteristics.