Modelling and simulation of a human knee exoskeleton's assistive strategies and interaction based on kinematics

The purpose of this study is to generate a realistic human knee exoskeleton model based on a physical system, create a human-machine system (HMS) in a musculoskeletal modelling software, and simulate assistive strategies and human-machine interaction based on joint kinematics. A knee exoskeleton was developed in CAD and then imported into a musculoskeletal simulation. A damped pendulum model was used to simulate the adaptive assistive strategy of the exoskeleton and to predict the torque during rhythmic flexion-extension of the knee, without prespecifying a reference trajectory. To compare the effectiveness of the proposed adaptive assistive strategy, three fixed (high, medium, low) assistive torque strategies depending on the required assistive torque were also simulated. Computed knee joint moment, knee joint reaction force, and human-exoskeleton interaction force were compared.