Design and Performance Analysis of a Parallel Mechanism Based Virtual Biomechanical Shoulder Robot Model

Abstract

The human shoulder complex provides an extensive spectrum of motion to the human upper arm, facilitating the accomplishment of the active daily life tasks. The in-silico musculoskeletal models presented in the literature can be used to study the associated kinematic parameters with the human shoulder. These models aid in the designing and control of rehabilitation robots. These models are sometimes oversimplified thus compromising their usage. This paper presents a Virtual 6-4 Parallel Biomechanical Shoulder Robot Model (VBSRM) as a musculoskeletal model. The kinematic model of the proposed VBSRM is developed. Performance metric such as condition number is identified to study the workspace of the VBSRM. A singularity analysis of the robot’s Jacobian matrix was carried out to avoid a possible singular design. In order to obtain the maximum workspace and optimal design of the VBSRM, design optimization was carried out using genetic algorithm. This proposed optimal design can be used in the shoulder functioning evaluations.