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

TL;DR

This paper introduces an extended-UDE based control method for mobile manipulators that effectively manages dynamic coupling, enhancing motion and force control during complex tasks like wall cleaning.

Contribution

It proposes a simplified dynamic coupling model and an extended UDE for improved control of mobile manipulators in dynamic environments.

Findings

Enhanced motion/force tracking accuracy

Faster response times in dynamic scenarios

Improved robot-environment interaction performance

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.