A computational simulated control system for a high-force pneumatic muscle actuator: system definition and application as an augmented orthosis

• Published in: Computer methods in biomechanics and biomedical engineering Vol. 12; no. 2; pp. 173 - 183
• Main Authors: Gerschutz, Maria J., Phillips, Chandler A., Reynolds, David B., Repperger, Daniel W.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis Group 01-04-2009
• Subjects: augmented orthosis; Biomechanical Phenomena; Biomedical Engineering; Computer applications; Computer Simulation; control system; feed-back control; Feedback; Humans; Information systems; Muscle Contraction; Muscles; Muscles - physiopathology; nonlinear systems; Orthotic Devices; phenomenological model; Phorbol esters; pneumatic muscle actuator; Pressure; Software; Software Design; Spinal Cord Injuries - physiopathology; Spinal Cord Injuries - rehabilitation; time constant
• ISSN: 1025-5842; 1476-8259
• DOI: 10.1080/10255840802372052

High-force pneumatic muscle actuators (PMAs) are used for force assistance with minimal displacement applications. However, poor control due to dynamic nonlinearities has limited PMA applications. A simulated control system is developed consisting of: (1) a controller relating an input position angle to an output proportional pressure regulator voltage, (2) a phenomenological model of the PMA with an internal dynamic force loop (system time constant information), (3) a physical model of a human sit-to-stand task and (4) an external position angle feed-back loop. The results indicate that PMA assistance regarding the human sit-to-stand task is feasible within a specified PMA operational pressure range.