Time-Division Multiplexing Actuation in Tendon-Driven Arms: Lightweight Design and Fault Tolerance

2026-04-18

AI Summary

This study addresses the challenge of achieving both lightweight design and fault-tolerant reliability in space robotic arms under stringent mass constraints. The authors propose an innovative architecture based on time-division multiplexed actuation (TDMA), integrating a vertically stacked rotary gating mechanism with self-rotating TDM motors, electromagnetic clutches, worm-gear reducers, and a dual-encoder system. This integration significantly reduces the number of actuators while enabling sub-0.1-second clutch response, inherent self-locking capability, and high-precision positioning. A complementary trajectory planning algorithm ensures fault-tolerant control even under partial servo failure. The resulting MuxArm prototype weighs only 2.17 kg, can manipulate a 10 kg payload, achieves end-effector positioning accuracy within 1% of arm length, and reduces tendon loading by 50%.

Technology Category

• Intelligent Robots: Manipulation
• Planning, Routing, and Scheduling: Replanning and Plan Repair
• Humans and AI: Planning and Decision Support for Human-Machine Teams

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Search and Retrieval-Augmented AI: Multilingual and cross-lingual Web search

Abstract

Robotic manipulators for aerospace applications require a delicate balance between lightweight construction and fault-tolerant operation to satisfy strict weight limitations and ensure reliability in remote, hazardous environments. This paper presents Time-Division Multiplexing Actuation (TDMA), a practical approach for tendon-driven robots that significantly reduces actuator count while preserving high torque output and intrinsic fault tolerance. The key hardware employs a vertically-stacked rotational selection structure that integrates self-rotating TDM motors for rapid configuration, electromagnetic clutches enabling sub-0.1 second engagement, a worm gear reducer for enhanced load capacity and self-locking capability, and a dual-encoder system for precise, long-term positioning. Leveraging TDMA, the proposed MuxArm achieves a self-weight of 2.17 kg, supports an actuator driving capacity of 10 kg, and maintains end-effector accuracy up to 1% of its length, even under partial servo failure. Additionally, an actuation space trajectory planning algorithm is developed, enabling fault-tolerant control and reducing tendon load by up to 50% compared to conventional methods. Comprehensive experiments demonstrate MuxArm's robust performance in diverse settings, including free-space, cluttered, and confined environments.

Problem

• lightweight design
• fault tolerance
• tendon-driven robots
• aerospace robotics
• actuation redundancy

Innovation

• Time-Division Multiplexing Actuation
• tendon-driven robot
• fault tolerance
• lightweight design
• actuation space trajectory planning