A New Methodology for Type Synthesis of Planar Linkages for Exoskeletons up to Five Angular Outputs

Mahmoud Helal,Abdulaziz H Alghtani,Hasan Eleashy,Jong Wan Hu

doi:10.3390/app12042238

Mahmoud Helal, Abdulaziz H Alghtani + Show 2 more

Open Access

https://doi.org/10.3390/app12042238

Copy DOI

Abstract

Mechanical linkage systems are a very important issue for exoskeleton design to meet the required number of angular outputs. In this paper, a new methodology is developed for type synthesis of planar linkages to establish a complete set of one degree of freedom (DOF) planar linkages with up to five angular outputs. Modified graphical representation is introduced for a four-bar mechanism as the initial angular output linkage. Then, a computerized procedure is presented to generate multiple angular outputs graphically by adding RRR dyads with parallel and series connections using Visual C++. A complete database of planar linkages with up to five angular outputs is successfully constructed. That helps designers to select the proper linkage for a given number of angular outputs. Some case studies have been discussed to validate the importance and efficiency of the proposed methodology that can be extended to generate linkage systems with any number of angular outputs for general robotic applications.

Highlights

IntroductionThe use of mechanical systems for medical applications has increased
In recent years, the use of mechanical systems for medical applications has increased.Rehabilitation processes are applied to eliminate deficiencies such as joint range of motion (ROM), muscle weakness and coordination in the upper or lower limb
Type synthesis is the process of generating all independent alternatives of exoskeleton linkage structures regardless of their dimensions

Summary

Introduction

The use of mechanical systems for medical applications has increased. Rehabilitation processes are applied to eliminate deficiencies such as joint range of motion (ROM), muscle weakness and coordination in the upper or lower limb. Many robotic systems have recently been proposed. An exoskeleton or rehabilitation robot is a powered wearable mechanism that can track the user’s movements. Type synthesis is the process of generating all independent alternatives of exoskeleton linkage structures regardless of their dimensions. The structure of a mechanism is defined by the number of links, number of joints, and their type. Several methods have been introduced for structural synthesis of mechanisms since the 1960s [1–5]. Type synthesis has been investigated by Olson et al [6] to develop a systematic procedure suitable for computer implementation. Graph theory and Assur group were applied to generate a group of kinematic structures with specified features

Methods

Results

Conclusion