Design of a Passive Exoskeleton Spine

In this chapter, a series of biomechanics simulations were conducted to reconstruct a specific movement – spine flexion/extension in sagittal plane of a subject. The motion capture was used to collect the kinematics information of the subject. These motions were used to drive a customized musculoskeletal model in OpenSim. Additionally, the muscle actuation forces and joint reactions were computed via forward simulations. The forward simulation results were then evaluated by comparing with prior published literature and were used to assist the design of a passive exoskeleton as described in Chapters 5-7. 3.1 Motion Capture and Data Collection This study involved human participants and was approved by the University of Massachusetts – Institutional Review Board (IRB). The test subject for this study was a 25-yearold, healthy male, 165 cm tall and 63kg. The motion capture and relative surface Electromyography (sEMG) data collection took place in the Biomechanics Laboratory at the University of Massachusetts Amherst. An eleven-camera Qualisys Oqus 3-Series optical motion capture system was used to capture the experimental marker kinematics. Motion capture markers were placed on the subject, as shown in Figure 3.1. The subject was required to start with a natural stance, flex forward approximate 90 degrees, and extend back to stance position. During the experiment, the subject was asked to finish several trials in a minute continuously with a consistent speed according to a timer beeping. The motion speed was set to be 3-second-flexion and 3-second-extension. All later