Energy-Efficient Multi Smart Materials Based Actuator Demonstrator Combining Shape Memory Alloy Wires With Electrostatic Clutches

Abstract This paper presents an actuator demonstrator showcasing a combination of shape memory alloy (SMA) wires and electrostatic (ES) clutches in a multi smart materials based actuator system. Shape memory alloy actuators demonstrate high energy densities and can transmit large actuation forces. However, they suffer from low energy efficiency due to the fact that they are thermal actuators. This drawback inhibits the adoption of SMA actuators in position-holding applications, for example, grasping objects using a robot hand. ES clutches can overcome this drawback of SMA actuators due to their high energy efficiency and ability to withstand high frictional shear stresses. A combination of the two actuator systems combining large actuation forces provided by SMA actuators with the energy-efficient actuation of ES clutches can be used in applications requiring the holding of a desired position or configuration. A demonstrator showcasing a combination of SMA wires with ES clutches demonstrating two different actuation modes: a linear actuator module and an SMA wire-actuated continuum robot is presented here. This demonstrator aims to showcase the versatility of this multi smart materials based actuator system in different actuation scenarios thereby opening further research avenues for smart materials based hybrid actuator systems for energy-efficient actuation.