RoboWalk: Comprehensive Augmented Dynamics Modeling and performance analysis

Document Type: Original Article

Authors

Department of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran

Abstract

Utilizing orthosis and exoskeletons has drawn a lot of attention in many applications including medical industries. These devices are used in the area of physical therapy to facilitate the patient’s exercises and as an assisting device to help the elderly carry out their daily activities. In this paper, the RoboWalk body-weight support assist device is introduced and its performance is analyzed by studying its influence on a human model. For this purpose, the forward kinematics of the human model and the inverse kinematics of RoboWalk are introduced in the first step. The dynamics of the human and a comprehensive model for RoboWalk are then obtained using the Newton-Euler method without considering the contact forces. These forces are then included in the model using the jacobian of contact points. The obtained models are then augmented to estimate the RoboWalk joint forces and torques, and those of the human model. The Recursive Newton Euler Algorithm and ADAMS software are used to verify the modeling obtained from the non-recursive Newton-Euler algorithm. The recursive algorithm is suitable for implementation purposes due to its low computational cost. After ensuring the accuracy of the obtained models, a control strategy is designed and implemented on RoboWalk. The performance of RoboWalk is then investigated by defining some criteria, e.g. floor reaction force and human model joint torques, before and after using RoboWalk.

Keywords