Model-Based Optimization for the Design of Exoskeletons that Help Humans to Sustain Large Pushes While Walking

• Published in: Converging Clinical and Engineering Research on Neurorehabilitation II Vol. 15; pp. 821 - 825
• Main Authors: Schemschat, R. Malin, Clever, Debora, Millard, Matthew, Mombaur, Katja
• Format: Book Chapter
• Language: English
• Published: Switzerland Springer International Publishing AG 2017; Springer International Publishing
• Series: Biosystems & Biorobotics
• Subjects: Biomedical engineering; Direct Multiple Shooting; Joint Torque; Pelvis Segment; Rehabilitation; User interface design & usability; Vicon Motion Capture System; Walking Motion
• ISBN: 9783319466682; 3319466682
• ISSN: 2195-3562; 2195-3570
• DOI: 10.1007/978-3-319-46669-9_134

In order to be useful in daily life, lower limb exoskeletons have to be able to provide support not only for nominal situations, such as level ground walking, but also for the recovery from extreme situations. In this paper, we investigate which torques a lower leg exoskeleton would have to produce in order to allow a person to recover from large perturbations or pushes that may occur while walking. We propose a model-based optimization approach that takes into account dynamic models of the human and the exoskeleton as well as experimental data of humans being pushed. Using optimal control and a least squares objective function we compute the joint torques that exoskeletons of different masses and mass distributions would have to produce in order to make the person follow the recorded recovery trajectories of healthy subjects and which loads would occur in the structure. The results of these computations can serve as guidelines for the design of future lower limb exoskeletons.