# Comparison Study of Well-Known Inverted Pendulum Models for Balance Recovery in Humanoid Robot

## TL;DR

This paper compares various inverted pendulum models for humanoid robot balance recovery, highlighting the superior performance of the Linear Inverted Pendulum Plus Flywheel model in challenging scenarios through analytical and simulation analysis.

## Contribution

It provides a comprehensive comparison of well-known inverted pendulum models for humanoid balance recovery, including analytical and simulation evaluations.

## Key findings

- Enhanced Linear Inverted Pendulum Plus Flywheel model outperforms others in stability recovery.
- Simulation results demonstrate effectiveness in push recovery scenarios.
- Hierarchical control structures can simplify complex humanoid walking control.

## Abstract

Bipedal robots are essentially unstable because of their complex kinematics as well as high dimensional state space dynamics, hence control and generation of stable walking is a complex subject and still one of the active topics in the robotic community. Nowadays, there are many humanoids performing stable walking, but fewer show effective push recovery under pushes. In this paper, we firstly review more common used abstract dynamics models for a humanoid robot which are based on the inverted pendulum and show how these models can be used to provide walking for a humanoid robot and also how a hierarchical control structure could fade the complexities of a humanoid walking. Secondly, the reviewed models are compared together not only in an analytical manner but also by performing several numerical simulations in a push recovery scenario using \mbox{MATLAB}. These theoretical and simulation studies quantitatively compare these models regarding regaining balance. The results showed that the enhanced version of Linear Inverted Pendulum Plus Flywheel is the ablest dynamics model to regain the stability of the robot even in very challenging situations.