Electrostatic Clutch-Based Mechanical Multiplexer with Increased Force Capability
This work addresses the actuator count bottleneck in multi-DoF robotic systems by providing a high-force, compact multiplexing solution for tendon-driven hands.
The authors developed an electrostatic capstan clutch-based mechanical multiplexer that enables both single-input-single-output and single-input-multiple-output actuation from a single motor, achieving output forces up to 212 N and a 4.09× increase in vertical grip strength in a four-DoF robotic hand.
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 of up to 212 N, increased vertical grip strength by 4.09 times, and raised horizontal carrying capacity to 111.2 N, the highest currently among five-fingered tendon-driven robotic hands. These results demonstrate that electrostatic-based multiplexing provides versatile actuation, overcoming the limitations of prior systems.