Control and Stability Analysis of a Walking Knee-less Biped with Torso

Seminal works in biped walking such as [1] had assumed favorable initial conditions on a limit cycle to start with. A more practical approach would be to start the biped from a static resting position. This paper proposes a simplified and straightforward approach for taking a biped robot from an initial resting position to a stable walking limit cycle. The biped model selected for the study is the ‘kneeless biped with torso’. The problem is tackled in two stages gait initiation from rest followed by convergence to stable walking. Walking is divided into various sub-phases depending on the state of the biped and simple state feedback control laws are proposed for each phase. The individual control laws are mathematically accrued into a single control law valid throughout the walking phase. Simulation results validating the approach are presented.