Stabilization of Bipedal Robot Motion based on Total Momentum

TL;DR

This paper introduces a novel stability control method for bipedal robots that uses total momentum and a human-inspired length shift strategy to maintain natural, efficient walking motion against disturbances.

Contribution

It proposes a momentum-based limit cycle stabilization approach combined with a length shift stabilizer, improving naturalness and efficiency of robot gait stability.

Findings

Effective in maintaining stability against disturbances

Produces human-like responses in robot gait

Enhances natural movement and energy efficiency

Abstract

Bipedal robots adapt to the environment of the modern society due to the similarity of movement to humans, and therefore they are a good partner for humans. However, maintaining the stability of these robots during walking/running motion is a challenging issue that, despite the development of new technologies and the advancement of knowledge, does not yet have a satisfactory solution. In most of the proposed methods by researchers, to maintain the stability of walking bipedal robots, it has been tried to ensure the momentary stability of motion by limiting the motion to multiple constraints. Although these methods have good performance in sustaining stability, they leave the robot away from the natural movement of humans, with low efficiency and high energy consumption. Hence, many researchers have turned to the walking techniques that follow a certain motion limit cycle, in which we can consider the overall stability rather than momentary. In this paper, a method is proposed to maintain the stability of the limit cycle against disturbance. For this purpose, the dynamical model of the biped robot is extracted in the space of total momentum variables and, according to the desired step length and speed, the motion limit cycle is designed. Subsequently, a motion stabilizer is proposed based on the idea of length shift, which is a natural human strategy for sustaining the balance in case of impact. The simulations show that this technique has a good performance in maintaining the stability of motion and has similar responses to human response.