A More Realistic Replica of a Walking Biped for Implying Dynamics and Control on Ascending and Descending Stairs by Cons

  • PDF / 9,283,619 Bytes
  • 24 Pages / 595.276 x 790.866 pts Page_size
  • 15 Downloads / 203 Views

DOWNLOAD

REPORT


RESEARCH PAPER

A More Realistic Replica of a Walking Biped for Implying Dynamics and Control on Ascending and Descending Stairs by Considering Self‑impact Joint Constraint Yousof Bazargan‑Lari1 · Ahmad Reza Khoogar2 Received: 1 February 2018 / Accepted: 17 June 2019 © Shiraz University 2019

Abstract The aim of this study was to bring forth a model-based control method for trajectory tracking of a normal human-like biped on descending and ascending stairs using the straight knee state and to verify the controller performance in the straight knee state periods. Contemplating a straight state in knee joints does not consent to each leg’s shank link to undertake angular rotations greater than thigh link’s rotations. For this purpose, among suggested methods, the self-impact joint constraint has been recommended for energy-efficient (normal) bipedal walking with the implementation of straight knee constraint. To reach this intention, dynamical motion equations are derived, developed and modified to comprise self-impact joint constraint at the knee joint. For gaining control over this complex dynamical system, accessible anthropometric stair gait cycle data are used to derive desired trajectories of thigh and shank links of self-impact biped. Furthermore, for taking the stair ascent and descent of the biped under control, a nonlinear intelligent controller with adaptive neural network control method was put forward. In proportion to simulation results on stair ascending and descending of biped robot, the biped could track the desired angular positions and velocities of the links very well despite having complex nonlinear terms in its governing dynamical equations due to the presence of self-impact constraints. Moreover, during the activation period of joint self-impact, an error of link position angles was evidently improved in comparison to unconstrained biped. Keywords  Walking · Self-impact joint constraint · Biped · Realistic model · Adaptive neural network · Stair descent · Stair ascent · Straight knee

1 Introduction Walking of humans is an evolutionary type of movement; such efficiency cannot be perceived in many other types. For instance, wheel movement only occurs in a continuous path. Such restrictions are not observed in human walking. Moreover, legs can be adapted to clutter environments more easily. Movement by legs can be bipedal, tetrapod, or like insects with more feet. Among these types of movements, biped gait increases the degrees of freedom (DOF), granting more access to the environment and diversity in movements. * Ahmad Reza Khoogar [email protected] 1



Department of Mechanical Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran



Department of Mechanical Engineering Maleke, Ashtar University of Technology Lavizan, Tehran, Iran

2

A biped robot is identified as a series of links that are coupled together and controlled by actuators located on the joints in order to perform bipedal gait. Biped robots and their locomotion have been the case of research for years. It is vital for