Bioinspired, Liquid Crystal Elastomer-Based Flexible Dexterous Finger for Deformation, Tactile, and Proximity Sensing

摘要

Soft actuators with self-driven deformation and environmental sensing capabilities are crucial for robotic exploration of complex, unknown spaces and for handling fragile objects. Unfortunately, most existing soft actuators have limited sensing functions, which significantly restricts their application potential in unknown environments. Here, inspired by the synergy between finger muscles and fingertip skin, we propose a flexible dexterous finger (FDF) based on liquid crystal elastomer (LCE) that can achieve deformation, tactile, and proximity sensing functions. The LCE actuator integrated with a microarray grid of carbon nanotube structures acts as the ‘finger,’ bending due to Joule heating from the current injected into the microstructure. Meanwhile, the resistance change in the microarray structure is used to sense its deformation. The proposed 3D-printed shared electrode capacitive sensor, composed of flexible interdigitated coplanar electrodes and a bottom electrode, serves as the ’fingertip skin’ for sensing proximity and tactile stimuli during grasping. To enhance the sensitivity of tactile sensing, a flexible microstructured array is proposed as the dielectric layer filling the center of the shared electrodes. The synergy of these three sensing functions provides the FDF with comprehensive perception capabilities. Results from the light-load flexible object grasping experiment show that the resistance changes in the microarray grid structure can reflect the bending deformation of the FDF in real-time. The fingertip skin pressure sensing sensitivity reaching 13 pF/kPa and proximity sensing sensitivity reaching 12.57 pF/mm. The application of the FDF in spatial load-grasping tasks demonstrates its potential in advanced robotics technology.