Variable Stiffness Dielectric Elastomer Actuator based on electrostatic chucking
Dielectric elastomer actuators (DEA) are one type of promising artificial muscle, however, applications of bending type DEA for robotic hands are limited by its low load capacity. DEA is able to generate a large force at the expense of large displacement; but it is not useful for robotic hands in the current state-of-the-art DEA technology. Researchers have proposed some methods to improve this issue by changing the stiffness of the actuator or adding another gripping method which does not rely on the actuator’s generative force. This work proposes a variable stiffness dielectric elastomer actuator (VSDEA) consisting of several unimorph type DEA units. Each DEA unit has an electrode for electrostatic chucking with another DEA unit to increase its thickness and stiffness. DEA units are additively manufactured by a high precision pneumatic dispenser, and assembled to form a VSDEA. Performance of DEA units and VSDEA are compared to model predictions. Finally, a two-claw actuator (0.6 grams) made of VSDEA is demonstrated to grasp and lift a 10 gram object.