Electrostatically Induced Multi-directional Vibro-impact Motions ^*

The unique asymmetric vibration motions of vibro-impact devices make them valuable in robotics and various industrial applications. However, achieving bidirectional vibro-impact motions in multiple degrees of freedom (DoF) remains challenging due to the inherent restrictions in conventional rigid actuators and predefined designs. Emerging soft robotic technologies have enabled programmable change in stiffness between rigid and compliant states, and actuation in multiple DoFs with a single actuator. This paper presents a novel 2-DoF programmable vibro-impact device based on innovative soft robotic technologies of electroadhesive (EA) clutches as the variable-stiffness constraints and a 2-DoF dielectric elastomer actuator (DEA) as the multi-directional vibration motion generator. The developed vibro-impact EA-DEA is capable of generating vibro-impact motions in bi-direction and in 2-DoF via coordinative programming of the actuation voltages of the EA and DEA modules and by harnessing the asymmetric stiffness profile of the activated EA module. The performances of the variable-stiffness EA module, 2-DoF DEA module, and the programmable vibro-impact motions of the EA-DEA device are investigated experimentally in this work. A multi-directional vibrating platform for material conveying and a multi-directional crawling robot are presented to demonstrate the potential applications of the EA-DEA in industries and robotics.