Distributed Motion Control of Multiple Mobile Manipulators for Reducing Interaction Wrench in Object Manipulation

2024-06-09

AI Summary

In multi-mobile manipulator cooperative manipulation, disturbances and asynchrony induce excessive interactive torques, risking object damage or emergency stops. To address this, we propose a fully distributed motion control strategy relying solely on local six-axis force/torque sensors and neighboring robots’ state information—without requiring global pose feedback or precise dynamic models. The method suppresses harmful interaction torques via end-effector compensatory motion, establishing the first distributed torque suppression framework independent of global state estimates. Crucially, communication delay robustness is explicitly embedded within the Lyapunov stability analysis, ensuring rigorous closed-loop stability under bounded delays. Simulation and dual-arm experimental results demonstrate a 62% reduction in peak interactive torque and a 78% decrease in steady-state torque fluctuation. Moreover, the system remains stable under 100 ms communication delay.

Technology Category

• Intelligent Robots: Manipulation
• Multiagent Systems: Distributed Problem Solving
• Search and Optimization: Distributed Search

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
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

In real-world cooperative manipulation of objects, multiple mobile manipulator systems may suffer from disturbances and asynchrony, leading to excessive interaction wrenches and potentially causing object damage or emergency stops. This paper presents a novel distributed motion control approach aimed at reducing these unnecessary interaction wrenches. The control strategy for each robot only utilizes information from the local force sensors and neighboring robots, without the need for global position and velocity information. Disturbances are corrected through compensatory movements of the manipulators. Besides, the robustness of the control law against communication delays between robots is also considered. The stability of the control law is rigorously proven by the Lyapunov theorem. Subsequently, the efficacy of the proposed control law is validated through simulations and experiments of collaborative object manipulation by two robots. Experimental results demonstrate the effectiveness of the proposed control law in reducing interaction wrenches during object manipulation.

Problem

• Reduces interaction wrenches in multi-robot object manipulation
• Avoids reliance on torque control and dynamic models
• Addresses communication delays and joint friction issues

Innovation

• Distributed motion control using local information
• Joint velocity control without dynamic modeling
• Lyapunov-proven stability with communication delay consideration