Head Stabilization for Wheeled Bipedal Robots via Force-Estimation-Based Admittance Control

TL;DR

This paper introduces a force-estimation-based admittance control method to actively stabilize the head of wheeled bipedal robots, improving sensor accuracy and payload safety on uneven terrain.

Contribution

The paper presents a novel model-based ground force estimation technique combined with admittance control for head stabilization in wheeled bipeds.

Findings

Real-time force estimation validated in simulations

Enhanced terrain adaptability demonstrated

Improved head stability on uneven terrain

Abstract

Wheeled bipedal robots are emerging as flexible platforms for field exploration. However, head instability induced by uneven terrain can degrade the accuracy of onboard sensors or damage fragile payloads. Existing research primarily focuses on stabilizing the mobile platform but overlooks active stabilization of the head in the world frame, resulting in vertical oscillations that undermine overall stability. To address this challenge, we developed a model-based ground force estimation method for our 6-degree-of-freedom wheeled bipedal robot. Leveraging these force estimates, we implemented an admittance control algorithm to enhance terrain adaptability. Simulation experiments validated the real-time performance of the force estimator and the robot's robustness when traversing uneven terrain.