An Underactuated Model of Bipedal Gait Based on a Biomechanical Analysis

This paper aims to propose an underactuated model of walking in bipeds in order to make a comparison with a biomechanical analysis. This study begins explaining some relevant concepts of underactuated mechanisms, and it shows some advances in this field. Then, a human body model and a simulation frame are created in a dynamic environment like SimMechanics from Matlab for performing bipedal gait simulations posteriorly. Segment Coordinate Systems (SCSs) and Body Segment Inertia Parameters (BSIPs) are set in the human body model, including the pelvis, thighs, calves and feet. Next, biomechanical bases for walking in humans are presented in order to get an overview of this area, in which phases of bipedal walking such as swing and stance are identified. Later, an underactuated model is presented based on the model proposed by Ramirez, where non-actuated joints are modeled as spring-damper systems. The swing phase of this approach is tested through simulation in the earlier created simulation frame starting from a set of initial conditions. Finally, results given by the simulation are compared with biomechanical data from literature.