Electrostatic Clutch-Based Mechanical Multiplexer with Increased Force Capability

Robotic systems with many degrees of freedom (DoF) are constrained by the demands of dedicating a motor to each joint, and while mechanical multiplexing reduces actuator count, existing clutch designs are bulky, force-limited, or restricted to one output at a time. The problem addressed in this study is how to achieve high-force, multiplexing that supports both simultaneous and sequential control from a single motor. Here we show an electrostatic capstan clutch-based transmission that enables both single-input-single-output (SISO) and single-input-multiple-output (SIMO) multiplexing. We demonstrated these on a four-DoF tendon-driven robotic hand where a single motor achieved output forces up to 212 N, increased vertical grip strength by 4.09 times, and raised horizontal carrying capacity by 354\% over manufacturer specifications. These results demonstrate that electrostatic multiplexing provides versatile actuation, overcoming the limitations of prior systems.