Electrostatic Clutches Enable Simultaneous Mechanical Multiplexing

Abstract: Actuating robotic systems with multiple degrees of freedom (DoF) traditionally requires numerous motors, leading to increased size, weight, cost, and power consumption. Mechanical multiplexing offers a solution by enabling a single actuator to control multiple DoF. However, existing multiplexers have either been limited to electrically controlled time-based multiplexing that control one DoF at a time or have relied on mechanical switching to control multiple DoF simultaneously. There is a strong need for a system that can perform electrically controlled multiplexing for both time-based and simultaneous control of multiple DoF. This study introduces a novel electrostatic capstan clutch-based mechanical multiplexer that enables high-force, single-motor control of multiple DoF. Here, we show that our system achieves both single-input-single-output (SISO) and single-input-multipleoutput (SIMO) actuation, allowing bidirectional control and position holding with minimal power consumption. Each output can actuate a 22.24 N load, limited by clutch performance, up to 5 cm. The number of outputs and actuation length is currently limited by the length of the drive shaft. We demonstrate the integration of our system into a 4-DoF commercial robotic hand using a single motor. These findings show that electrostatic clutchbased multiplexing provides a scalable and energy-efficient design solution for high-DoF robotic platforms, opening new possibilities for lightweight and power-efficient actuation in robotics.