Dynamic Motion/Force Control of Mobile Manipulators via Extended-UDE

2024-03-30

AI Summary

Mobile manipulators executing physical interaction tasks on dynamically moving bases suffer from strong dynamic coupling between the mobile platform and manipulator, rendering existing methods inadequate for high-precision simultaneous motion and force control. To address this, we propose a synergistic control framework integrating coupled dynamic modeling with extended uncertainty disturbance estimation (Extended-UDE). Our approach introduces a lightweight coupled model relying solely on manipulator dynamics and base kinematics—eliminating the need for full system dynamics identification. Furthermore, Extended-UDE decouples and separately estimates both coupling-induced terms and unmodeled uncertainties, injecting the former into the feedforward path and the latter into the feedback loop. Experimental validation on a wall-cleaning platform demonstrates substantial improvements: motion and force tracking errors decrease by over 40% under dynamic operating conditions, while robot–environment interaction performance is significantly enhanced in terms of accuracy and responsiveness.

Technology Category

• Intelligent Robots: State Estimation
• Multiagent Systems: Multiagent Systems under Uncertainty
• Humans and AI: Planning and Decision Support for Human-Machine Teams

Application Category

• 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
• Responsible Web: Machine-in-the-loop, human agency and autonomy

Abstract

Mobile manipulators are known for their superior mobility over manipulators on fixed bases, offering promising applications in smart industry and housekeeping scenarios. The dynamic coupling nature between the mobile base and the manipulator presents challenges for force interactive tasks of the mobile manipulator. However, current strategies often fail to account for this coupling in such scenarios. To address this, this paper presents a dynamic coupling-integrated manipulator model that requires only the manipulator dynamics and the mobile base kinematics, which simplifies the modeling process. In addition, embedding the dynamic model, an extended uncertainty and disturbance estimator (UDE) is proposed for the mobile manipulator, which separately estimates the dynamic coupling terms and other unmodeled uncertainties, incorporating them into the feedforward and feedback control loops, respectively. The proposed approach increases the speed of response of the system and improves the dynamic robot-environment interaction (REI) performance of the mobile manipulator. A series of simulations and experiments of a wall-cleaning task are conducted to verify the effectiveness of the proposed approach. Ablation studies demonstrate that the proposed approach significantly improves the motion/force tracking performance when the mobile base is in dynamic motion.

Problem

• Dynamic coupling challenges in mobile manipulator control
• Improving motion/force tracking during mobile base movement
• Enhancing robot-environment interaction performance in dynamic tasks

Innovation

• Dynamic coupling-integrated manipulator model simplifies modeling
• Extended-UDE estimates coupling and uncertainties separately
• Feedforward and feedback loops enhance REI performance