Design and manufacture of a novel systemto simulate the biomechanics of basic and pitching shoulder motion. Issue 5 (May 2012) - Entezari, V.
Abstract : Objectives: Cadaveric models of the shoulder evaluate discrete motion segmentsusing the glenohumeral joint in isolation over a defined trajectory.The aim of this study was to design, manufacture and validate arobotic system to accurately create three-dimensional movement ofthe upper body and capture it using high-speed motion cameras. Methods: In particular, we intended to use the robotic system to simulatethe normal throwing motion in an intact cadaver. The robotic systemconsists of a lower frame (to move the torso) and an upper frame(to move an arm) using seven actuators. The actuators accuratelyreproduced planned trajectories. The marker setup used for motioncapture was able to determine the six degrees of freedom of allinvolved joints during the planned motion of the end effector. Results: The testing system demonstrated high precision and accuracy basedon the expected versus observed displacements of individual axes.The maximum coefficient of variation for displacement of unloadedaxes was less than 0.5% for all axes. The expected and observedactual displacements had a high level of correlation with coefficientsof determination of 1.0 for all axes. Conclusions: Given that this system can accurately simulate and track simpleand complex motion, there is a new opportunity to study kinematicsof the shoulder under normal and pathological conditions in a cadavericshoulder model.