Markovian Transparency Control of an Exoskeleton Robot

Author(s)

Escalante, Felix M. ; dos Santos, Leonardo F. ; Moreno, Yecid ; Siqueira, Adriano A. G. ; Terra, Marco H. ; Boaventura, Thiago

• Document type: Journal article
• Source: IEEE ROBOTICS AND AUTOMATION LETTERS; v. 8, n. 2, p. 8-pg., 2023-02-01.

Abstract

In wearable robotics, certain applications require the robot to be transparent, i.e., imperceptible to the user. This is a very difficult cooperative control task due to the inherent coupling between human and robot, unpredictable human movements, and user-dependent behavior. In this letter, we propose a novel transparency controller based on discrete-time Markovian jump linear systems to minimize the human-robot interaction forces of an exoskeleton robot during walking. Our model-based stochastic control approach describes a gait cycle as an event-dependent Markov chain and uses a given transition matrix to switch between them. An IMU-based Kalman filter is used to perform real-time human state estimation and gait phase detection. The robustness and effectiveness of the proposed controller are demonstrated with experiments on a lower-limb exoskeleton driven by series elastic actuators. (AU)

• FAPESP's process: 19/05937-7 - Hybrid adaptive strategies for lower limb exoskeletons
• Grantee: Adriano Almeida Gonçalves Siqueira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 21/09244-6 - Impedance controllers benchmark
• Grantee: Leonardo Felipe Lima Santos dos Santos
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 18/15472-9 - Hydraulic actuation impedance control for robots with legs and arms
• Grantee: Thiago Boaventura Cunha
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 22/06634-0 - Implementation of force and impedance control strategies for robots with legs and arms in physical interaction applications.
• Grantee: Felix Mauricio Escalante Ortega
• Support Opportunities: Scholarships in Brazil - Technical Training Program - Technical Training