title: A Cyber Expert System for Auto-Tuning Powered Prosthesis Impedance Control Parameters.
abstract: Typically impedance control parameters (e.g., stiffness and damping) in powered lower limb prostheses are fine-tuned by human experts (HMEs), which is time and resource intensive. Automated tuning procedures would make powered prostheses more practical for clinical use. In this study, we developed a novel cyber expert system (CES) that encoded HME tuning decisions as computer rules to auto-tune control parameters for a powered knee (passive ankle) prosthesis. The tuning performance of CES was preliminarily quantified on two able-bodied subjects and two transfemoral amputees. After CES and HME tuning, we observed normative prosthetic knee kinematics and improved or slightly improved gait symmetry and step width within each subject. Compared to HME, the CES tuning procedure required less time and no human intervention. Hence, using CES for auto-tuning prosthesis control was a sound concept, promising to enhance the practical value of powered prosthetic legs. However, the tuning goals of CES might not fully capture those of the HME. This was because we observed that HME tuning reduced trunk sway, while CES sometimes led to slightly increased trunk motion. Additional research is still needed to identify more appropriate tuning objectives for powered prosthetic legs to improve amputees' walking function.
authors.affiliation: UNC/NCSU Joint Department of Biomedical Engineering, North Carolina State University, 4402D Engineering Building III, Raleigh, NC, 27695, USA. hhuang11@ncsu.edu.|UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, 150A MacNider Hall, Chapel Hill, NC, 27599, USA. hhuang11@ncsu.edu.
authors.forename: He
authors.initials: H
authors.lastname: Huang
authors.affiliation: UNC/NCSU Joint Department of Biomedical Engineering, North Carolina State University, 4402D Engineering Building III, Raleigh, NC, 27695, USA.|UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, 150A MacNider Hall, Chapel Hill, NC, 27599, USA.
authors.forename: Dustin L
authors.initials: DL
authors.lastname: Crouch
authors.affiliation: UNC/NCSU Joint Department of Biomedical Engineering, North Carolina State University, 4402D Engineering Building III, Raleigh, NC, 27695, USA.|UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, 150A MacNider Hall, Chapel Hill, NC, 27599, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Liu
authors.affiliation: UNC/NCSU Joint Department of Biomedical Engineering, North Carolina State University, 4402D Engineering Building III, Raleigh, NC, 27695, USA.|UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, 150A MacNider Hall, Chapel Hill, NC, 27599, USA.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Sawicki
authors.affiliation: UNC/NCSU Joint Department of Biomedical Engineering, North Carolina State University, 4402D Engineering Building III, Raleigh, NC, 27695, USA.|UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, 150A MacNider Hall, Chapel Hill, NC, 27599, USA.
authors.forename: Ding
authors.initials: D
authors.lastname: Wang
mesh_terms: D000843:Ankle Joint; D017097:Electric Impedance; D005260:Female; D005684:Gait; D006801:Humans; D007719:Knee Joint; D007720:Knee Prosthesis; D008297:Male; D016138:Walking
keywords: Biomechanics; Calibration; Expert system; Gait; Powered prosthetic legs; Transfemoral amputation