A Three-Level Whole-Body Disturbance Rejection Control Framework for Dynamic Motions in Legged Robots

2025-08-19

AI Summary

To address insufficient dynamic stability and robustness of legged robots under model uncertainty, external disturbances, and actuator failures, this paper proposes a three-layer whole-body disturbance-rejection control framework. Methodologically, it integrates whole-body dynamics modeling, optimization-based whole-body control, and Gazebo simulation, with experimental validation on both humanoid and quadruped platforms. Key contributions include: (1) a moving-horizon extended state observer (MH-ESO) enabling high-accuracy, real-time estimation of full system states and composite disturbances; and (2) a hierarchical optimization-based control architecture unifying nominal motion planning and disturbance compensation to jointly ensure motion performance and robustness. Extensive experiments on a physical quadruped robot demonstrate significant improvements in payload capacity, disturbance rejection, and fault tolerance—particularly under severe conditions such as sustained external impacts and single-joint actuator failure—while maintaining stable dynamic locomotion.

Technology Category

• Intelligent Robots: State Estimation
• Planning, Routing, and Scheduling: Replanning and Plan Repair
• Search and Optimization: Sampling/Simulation-based Search

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

This paper presents a control framework designed to enhance the stability and robustness of legged robots in the presence of uncertainties, including model uncertainties, external disturbances, and faults. The framework enables the full-state feedback estimator to estimate and compensate for uncertainties in whole-body dynamics of the legged robots. First, we propose a novel moving horizon extended state observer (MH-ESO) to estimate uncertainties and mitigate noise in legged systems, which can be integrated into the framework for disturbance compensation. Second, we introduce a three-level whole-body disturbance rejection control framework (T-WB-DRC). Unlike the previous two-level approach, this three-level framework considers both the plan based on whole-body dynamics without uncertainties and the plan based on dynamics with uncertainties, significantly improving payload transportation, external disturbance rejection, and fault tolerance. Third, simulations of both humanoid and quadruped robots in the Gazebo simulator demonstrate the effectiveness and versatility of T-WB-DRC. Finally, extensive experimental trials on a quadruped robot validate the robustness and stability of the system when using T-WB-DRC under various disturbance conditions.

Problem

• Enhancing legged robot stability against uncertainties and disturbances
• Estimating and compensating for whole-body dynamic uncertainties
• Improving payload transport, disturbance rejection, and fault tolerance

Innovation

• Moving horizon extended state observer for uncertainty estimation
• Three-level whole-body disturbance rejection control framework
• Simulation and experimental validation on legged robots