Unilateral Ground Contact Force Regulations in Thruster-Assisted Legged Locomotion

TL;DR

This paper introduces a novel approach using Reference Governors to efficiently regulate ground contact forces in thruster-assisted legged robots, enhancing stability and control without high computational costs.

Contribution

It demonstrates the application of Reference Governors for GRF regulation in a thruster-assisted bipedal robot, offering a faster alternative to traditional optimization methods.

Findings

RGs effectively enforce GRF constraints in real-time

Thrusters enable flexible gait adjustments without losing stability

Method reduces computational complexity in legged robot control

Abstract

In this paper, we study the regulation of the Ground Contact Forces (GRF) in thruster-assisted legged locomotion. We will employ Reference Governors (RGs) for enforcing GRF constraints in Harpy model which is a bipedal robot that is being developed at Northeastern University. Optimization-based methods and whole body control are widely used for enforcing the no-slip constraints in legged locomotion which can be very computationally expensive. In contrast, RGs can enforce these constraints by manipulating joint reference trajectories using Lyapunov stability arguments which can be computed much faster. The addition of the thrusters in our model allows to manipulate the gait parameters and the GRF without sacrificing the locomotion stability.