REWW-ARM -- Remote Wire-Driven Mobile Robot: Design, Control, and Experimental Validation

TL;DR

This work introduces the Remote Wire Drive concept to physically separate electronics from the operating environment, enabling electronics-free distal robots to be powered and controlled remotely. The REWW-ARM proof-of-concept integrates a motor-unit, a novel Remote Wire Transmission Mechanism (RWTM), and an electronics-free distal snake robot to achieve closed-loop control via wire-based actuation. Experimental results demonstrate reliable locomotion, peristaltic manipulation, and underwater operation with high transmission efficiency ($ar{η}=0.884$) and robust environmental resistance. The approach offers a pathway to extend operational envelopes for robots in harsh environments where traditional electronics would be compromised.

Abstract

Electronic devices are essential for robots but limit their usable environments. To overcome this, methods excluding electronics from the operating environment while retaining advanced electronic control and actuation have been explored. These include the remote hydraulic drive of electronics-free mobile robots, which offer high reachability, and long wire-driven robot arms with motors consolidated at the base, which offer high environmental resistance. To combine the advantages of both, this study proposes a new system, "Remote Wire Drive." As a proof-of-concept, we designed and developed the Remote Wire-Driven robot "REWW-ARM", which consists of the following components: 1) a novel power transmission mechanism, the "Remote Wire Transmission Mechanism" (RWTM), the key technology of the Remote Wire Drive; 2) an electronics-free distal mobile robot driven by it; and 3) a motor-unit that generates power and provides electronic closed-loop control based on state estimation via the RWTM. In this study, we evaluated the mechanical and control performance of REWW-ARM through several experiments, demonstrating its capability for locomotion, posture control, and object manipulation both on land and underwater. This suggests the potential for applying the Remote Wire-Driven system to various types of robots, thereby expanding their operational range.

Figures (21)

• Figure 1: Overview of REWW-ARM, the Remote Wire-Driven robot developed in this study. Power is physically transmitted from the motor-unit in the background to the snake-like robot in the foreground through the slender Remote Wire Transmission Mechanism.
• Figure 2: Overview of design. REWW-ARM consists of three elements: a motor-unit that generates power, a Remote Wire Transmission Mechanism (RWTM) that transmits power, and a distal mobile robot that is driven by the transmitted power. The distal mobile robot is further composed of three Gear-Coupled Dual-Axis Joints (GCD-Joints), two Variable-Stiffness Contract Links (VSC-Links), and one Anchor-Gripper Integrated End-Effector (AGI-EE), which cooperate to enable locomotion and object manipulation.
• Figure 3: The motor-unit consists of six winch modules controlled by CAN communication, controlling six wires.
• Figure 4: The RWTM has a structure in which tendon-sheath mechanisms and decoupled joints are alternately connected in series. The high flexibility of the tendon-sheath mechanism and the high and stable transmission efficiency of the decoupled joint complement each other, enabling stable and highly efficient transmission without hindering the movement of the distal mobile robot.
• Figure 5: Examples of wire mechanisms that do not work as an RWTM. External forces are applied to the distal mobile robot due to wire tension or lack of flexibility, hindering its movement.