Comparative study on gait patterns of biped robotic system

Abstract

Biped robots are distinct systems owing to their multi-degree of freedom construction, intrinsic instability, and highly nonlinear dynamics. Owing to these, gait pattern generation to ensure stable locomotion represents an important area of research for these robotic systems. The purpose of gait pattern generation for biped robot is to infuse stability in the system by giving each joint a predetermined position with respect to time. In this work, the effectiveness of two different gait patterns for bipedal walking has been investigated, compared and the results are presented. The gait patterns investigated are the one based on Rolling Sphere Model (RSM) with predefined Zero Moment Point (ZMP) as stability criteria and the gait pattern based on 3D Linear Inverted Pendulum Model (LIPM) with tracking of Capture Point (CP). As the design of Center of Mass (CoM) trajectory forms the basis of such model based gait pattern generations, the effect of CoM trajectory on the stability of biped robotic system is analyzed. The variations in other parameters such as joint positions and torques, ZMP determined with the help of contact forces of the ground, and comparative study in terms of kinetic energy and total energy is carried out and the results are presented. It is observed that the case dealing with ZMP based gait pattern offers an efficient method in terms of consumption of energy.