1. Optimal design and control of an electromechanical transfemoral prosthesis with energy regeneration
- Author
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Farbod Rohani, Hanz Richter, and Antonie J. van den Bogert
- Subjects
Male ,030506 rehabilitation ,Knee Joint ,Computer science ,Physiology ,medicine.medical_treatment ,Knees ,lcsh:Medicine ,Walking ,Knee Joints ,Prosthesis ,0302 clinical medicine ,Gait (human) ,Medicine and Health Sciences ,Femur ,lcsh:Science ,Musculoskeletal System ,Gait ,Prosthetics ,Multidisciplinary ,Physics ,Classical Mechanics ,Transfemoral prosthesis ,Power (physics) ,Biomechanical Phenomena ,medicine.anatomical_structure ,Physical Sciences ,Legs ,Engineering and Technology ,Female ,Anatomy ,0305 other medical science ,Knee Prosthesis ,Research Article ,Biotechnology ,Optimal design ,Adult ,Artificial Limbs ,Capacitors ,Prosthesis Design ,03 medical and health sciences ,Motion ,Control theory ,Mechanical Energy ,medicine ,Torque ,Humans ,Mechanical energy ,Biological Locomotion ,lcsh:R ,Limbs (Anatomy) ,Ankles ,Biology and Life Sciences ,Preferred walking speed ,Assistive Technologies ,Joints (Anatomy) ,Energy Transfer ,lcsh:Q ,Medical Devices and Equipment ,Ankle ,Electronics ,030217 neurology & neurosurgery ,Ankle Joint - Abstract
In this paper, we present the design of an electromechanical above-knee active prosthesis with energy storage and regeneration. The system consists of geared knee and ankle motors, parallel springs for each motor, an ultracapacitor, and controllable four-quadrant power converters. The goal is to maximize the performance of the system by finding optimal controls and design parameters. A model of the system dynamics was developed, and used to solve a combined trajectory and design optimization problem. The objectives of the optimization were to minimize tracking error relative to human joint motions, as well as energy use. The optimization problem was solved by the method of direct collocation, based on joint torque and joint angle data from ten subjects walking at three speeds. After optimization of controls and design parameters, the simulated system could operate at zero energy cost while still closely emulating able-bodied gait. This was achieved by controlled energy transfer between knee and ankle, and by controlled storage and release of energy throughout the gait cycle. Optimal gear ratios and spring parameters were similar across subjects and walking speeds.
- Published
- 2017