A Soft Actuator with Tunable Mechanical Configurations for Object Grasping Based on Sensory Feedback

摘要

In this paper, we propose a soft actuator embedded with conductive liquid alloy (eGaIn) and Shape Memory Polymer (SMP). The conductive liquid alloy functions as bending sensor as well as pressure sensor. The three segments of the SMP layer can be heated optionally by applying 400mA current to different sections of the conductive silver fiber to achieve tunable stiffness, and enable the soft actuator with variable degree-of-freedom (DoF) configurations. Through real-time feedback of the bending sensor that has been calibrated, we realized proprioception of all mechanical configurations of the soft actuator under free load. We also achieved geometrical feature recognition of different objects while all segments of the actuator were softened. Finally, experimental verification of the prototype was conducted on a variety of objects in condition that the geometrical features were unknown. The results show improved enveloping and reliable grasping performance.