Task-Based Design Approach: Development of a Planar Cable-Driven Parallel Robot for Upper Limb Rehabilitation

Ferdaws Ennaiem,Sami Bennour,Saïd Zeghloul,Lotfi Romdhane,Med Amine Laribi,Abdelfattah Mlika,Juan Sandoval,Abdelbadiâ Chaker

doi:10.3390/app11125635

Abstract

This paper deals with the optimal design of a planar cable-driven parallel robot (CDPR), with three degrees of freedom, intended for assisting the patient’s affected upper limb along a prescribed movement. A Qualisys motion capture system was used to record the prescribed task performed by a healthy subject. For each pose taken by the center of mass of the end-effector, the cable tensions, the elastic stiffness and the dexterity were optimized while satisfying a set of constraints. First, a multiobjective formulation of the optimization problem was adopted. Since selecting a single solution among the multiple ones given by the Pareto front presents an issue, a mono-objective formulation was chosen, where the objective function was defined as a weighted sum of the chosen criteria. The appropriate values of the weighted coefficients were studied with the aim of identifying their influence on the optimization process and, thus, a judicious choice was made. A prototype of the optimal design of the CDPR was developed and validated experimentally on the prescribed workspace using the position control approach for the motors. The tests showed promising reliability of the proposed design for the task.

Highlights

Functional rehabilitation aims to recover as much as possible of the patient’s locomotion independence. It requires the assistance of a therapist to perform repetitive exercises for an injured member [1]
Task-oriented protocols, where the patient is assisted to perform a specific prescribed movement, such as kicking a ball or standing up and walking, show promising outcomes compared to the conventional training based on passively moving the impaired joints in the limits of their range of motion [2]
Rehabilitation aims to recover the functional abilities of the affected member by performing intensive and repetitive training [1]

Summary

Introduction

Functional rehabilitation aims to recover as much as possible of the patient’s locomotion independence. It requires the assistance of a therapist to perform repetitive exercises for an injured member [1]. The limited number of available therapists influences the high-intensity and the repetition of the assistance Given these issues, researchers have developed robotic devices to assist practitioners’ tasks [5,6,7,8,9]. Researchers have developed robotic devices to assist practitioners’ tasks [5,6,7,8,9] They provide the opportunity to assess the patient’s recovery progress and monitor protocol efficiency; for instance, by using ARMin [10], the ARM Guide [11], and the MIME [12]

Objectives

Methods

Conclusion