Session: MR-06-01 - Medical and Rehabilitation Robotics

Paper Number: 91305

91305 - Integration of EMG-Based Learning and Sliding Mode Control for an Exoskeleton Assist-as-Needed Support System 

In this study, an
Electromyography (EMG) signal-based learning is integrated with a Sliding-Mode Control(SMC) law for an effective human-exoskeleton synergy. The SMC, chosen due to its robustness to parameters' uncertainties of the system, and a modified Recursive Newton-Euler Algorithm (RNEA) are used to control and determine the inverse dynamics of a highly nonlinear 4 degree-of-freedom exoskeleton robot. The exoskeleton position and velocity, along with the raw EMG signal of the bicep Brachii were used as a feedback. The algorithm is tested
on an exoskeleton designed for the automation of upper-limp therapeutic exercises. EMG signal is fed to the proposed algorithm to automatically learn and determine the support needed by the subject to accomplish
the desired task. The root mean square (RMS) values of targeted muscles EMG
are tracked in a predetermined time window to quantify an adaptive threshold
value and control the torque at the exoskeleton joints. Simulations of the proposed robust control law have been done in MATLAB-Simulink. Results have shown that the designed hybrid Control strategy offers the ability to adjust the needed support instantly based on the amount of muscle engagement presented in the combined motion of the human-exoskeleton system while maintaining the state trajectory errors and input torque bounded to -0.007 to 0.007 rads and -5 to 5 N.m, respectively.

Presenting Author: Pablo Delgado Wichita State University

Presenting Author Biography: Pablo Delgado is a PhD student in the department of mechanical engineering at Wichita State University. He received his masters degree from Rochester Institute of Technology, New York, NY, Dec 2016, and his bachelors degree from Potificia Universidad Catolica Madre y Maestra, San-tiago, Dominican Republic, Dec 2013 both in Electrical Engineering. Before joining WSU, he was teaching undergraduate courses at the Pontificia Universidad Catolica Madre y Maestra, in the Dominican Republic for two years. During his first year of graduate study at the Mechanical Engineering (ME) department at WSU, he developed fully online instruction materials and computer-based projects for a senior-level course - Mechanical Control Systems (ME 659) and offered it for ME undergraduate students over summer of 2020. He is currently working on an NSF funded research project, Bio-inspired Exoskeletons for an effective human-exoskeleton alignment and coordination.

Authors:

Pablo Delgado Wichita State University
Nathan Gonzalez Wichita State University
Yimesker Yihun Wichita State University