White Papers

Spherical Exoskeleton for the Measurement of Shoulder Movement

Authors: Jiaji Li, John Golden, Bailey E. Johnson, Edward Quilligan, Vance 0. Gardner, MD, Carlos A. Prietto, MD, and John Michael McCarthy

This study was presented as a presentation at the Canadian Committee for the Theory of Machines and Mechanisms (CCToMM) M3 Symposium and published in the Transactions of the Canadian Society for Mechanical Engineering Journal.

Abstract: This paper presents the design, construction, and testing of a spherical shoulder exoskeleton that measures shoulder movement for use before and after reverse total shoulder arthroplasty. The device is designed for in-home use to facilitate remote physiotherapy. Embedded sensor data are converted to a robotic shoulder model to illustrate the measured movement, and which is validated through Image measurements. Unlike current motion capture and image processing measurement techniques, this device measures the movement of the upper arm relative to the scapula, excluding scapula movement, thereby focusing on movement provided by the shoulder prosthesis.

Figure 1.

photo of mechanical device
Fig. 1. The spherical exoskeleton system designed to measure shoulder movement. The first version on the left (white) was manufactured with Siraya Tech Tenacious. The second version on the right (black) was manufactured with Formlab Tough 2000.

Figure 2.

illustration of model with markings labeling the parts
Fig. 2. A solid model of the spherical exoskeleton system that shows the spherical scissor mechanism that wraps around the shoulder of the patient.

Figure 3.

image of boy with device on arm
Fig. 3. Photographs of flexion and external rotation test using the initial shoulder exoskeleton. (a) Initial position, side view, (b) flexion movement, side view, (c) flexion movement, top view, and (d) external rotation, top view.