Estimation of Ground Reaction Force for Coupled Dynamic Modelling and Control of the Lower Limb Exoskeleton

Advances in Robotics - International Conference of The Robotics Society (AIR), vol. 202, pp. 1–8

Abstract

In order to achieve the desired control of a lower limb exoskeleton, an understanding of the dynamics of the coupled human-exoskeleton system is required. A major input towards modelling the dynamics of the coupled system is the ground reaction force (GRF) generated by the human wearing the exoskeleton. Therefore, the GRF from the coupled system needs to be either computed, measured or estimated. This paper presents work on the estimation of GRF and subsequently on the control of a lower-limb exoskeleton. The approach to estimating GRF is based on the multiple variable regression technique, which considers the body weight, height and walking speed of the exoskeleton user. A mathematical model based on the Euler-Lagrange formulation was used to model the complete system. Once the dynamic model is ready, strength augmentation for the purpose of load-carrying exoskeletons is set as a desired control objective, and further computed torque control is tested on the coupled system. In summary, this paper tries to achieve three goals: estimation of GRF, dynamic modelling of the coupled human-exoskeleton system and formulation of a control framework from the modelled dynamics for testing computed-torque control.

Authors 3

1. Sekar Anup Chander

   Academy of Scientific and Innovative Research

   Affiliation as printed

   CSIR-CSIO, Academy of Scientific and Innovative Research (AcSIR), IN

2. Ashutosh Mukherjee Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Germany

3. Ashish Singla

   Thapar Institute of Engineering & Technology

   Affiliation as printed

   Department of Mechanical Engineering, Thapar Institute of Engineering and Technology, IN