Investigation of Wearable Motion Capture System Towards Biomechanical Modelling

Abstract

Motion Capture (MOCAP) systems provide kinematic data as an output. Biomechanical models use this data as an input to calculate the forces acting on the joints of human body. For high bio-fidelity modelling, accurate daily life data are required. Here, we asses a novel marker-less wearable MOCAP system, SmartSuit Pro (Rokoko, Copenhagen, Denmark) for feeding in data to a biomechanical modelling software. This suit is utilised for medical data collection purposes for the first time. The study provides proof of concept for the upper body motion in vitro using 5th percentile female skeleton model. Flexion -extension movements of the shoulder and elbow were simulated using controlled step motor to quantify the deviation between the planned and the measured profile by the wearable suit. Cross validation is completed in vivo using Optitract (LEYARD,Corvallis, USA). In vivo data was collected from healthy volunteers with no previous history of upper extremity disorder. For repeatability and reliability purposes, 3 sets of motions were repeated 3 times to measure flexion/extension range of motion (RoM). The relative peak angles were calculated. Root Mean Square Error (RMSE) was as 0.46° and 0.31° respectively for shoulder and elbow. In vivo, RMSE values for shoulder and elbow flexion were 0.66° and 0.51° respectively. Pearson correlation coefficient was calculated as 0.7° and 0.77° for shoulder and elbow between OptiTrack and Smartsuit Pro respectively. Bland - Altman plots showed that Rokoko system produces data comparable to OptiTrack. The collected data was fed into Biomechanics of Bodies (BoB) simulation software for calculating kinetic data. In conclusion, Rokoko system could be an alternative solution while measuring RoM for biomedical purposes.