Dynamics modeling of a biped robot with active toe joints

Abstract

This paper suggests an approach to develop dynamics model and proposes a novel method to solve inverse dynamics of a biped robot with active toe joints. In order to obtain closed-form dynamics model, first, equations of motion are developed for the robot with no interaction. Then, consistent with constraints, unknown forces and moments are considered, using constraints relaxation method. These forces and moments are different during various phases of motion for the robot which is equipped with active toe joints. In our dynamics modeling method, the double support phase is divided into two subphases, depending on the action of toe joint. Then, to compute joints actuating torques and ground reaction forces and moments, inverse dynamics problem for each subphase is solved. The simulation results for walking on flat ground surface illustrate that the proposed approach is effectively used for dynamics modeling of biped robots with redundant legs. Finally, the actual ZMP trajectory is computed using obtained reaction forces and moments to guarantee the feasibility of the generated walking pattern.

Modelling, Simulation and Control of the Walking of Biped Robotic Devices—Part I : Modelling and Simulation Using Autolev

“…span, respectively null-space and range of u. In order to obtain the most robust variables, permute the components of u in the independent generalized speeds so as to minimize the conditioning number of either equation (15) or (16). Moreover, it is always possible to handle an holonomic (configuration) constraint as if it is non-holonomic, that is, to treat it as a motion constraint.…”

“…This is equivalent to a hinge on the toes or on the heels of the foot/feet on the ground, resulting in 13 or 14 joints that can be potentially controlled, in single or double stance, respectively. In fact, to guarantee a human like walk it is mandatory that toe alone, or toe and heel joints are active [14][15][16]. Assuming the system free to move in the sagittal and frontal planes, but for simplicity not to rotate along the z axis (the walk is considered to be along a straight line without turns), it is characterized by 17 DOF and an identical number of generalized variables and speeds, chosen here as the derivatives of the generalized variables.…”

Design of Biomechanical Legs with a Passive Toe Joint for Enhanced Human-like Walking

“…The toe joint itself has been represented as either a powered joint (Ezati et al 2014;Hernández-Santos et al 2012;Nishiwaki et al 2002) or as a passive joint (Sellauoti et al 2006). In this paper, a study case of a biomechanical leg with a passive toe joint represented by torsion springs is considered.…”