Fuzzy optimal control of sit-to-stand movement in a biomechanical model

Article type: Research Article

Authors: Mughal, Asif Mahmood | Iqbal, Kamran

Affiliations: Center for Advanced Studies in Engineering, Islamabad, Pakistan | Department of Systems Engineering, University of Arkansas at Little Rock, Little Rock, AR, USA

Note: [] Corresponding author. Dr. Asif M. Mughal, Center for Advanced Studies in Engineering, Islamabad, Pakistan. E-mail: [email protected]

Abstract: The Physiological studies illustrate that human sit-to-stand (STS) movement consists of different phases that are distinguishable by their kinematics constraints and stability requirements. We propose to use a fuzzy TSK biomechanical model to analyze, integrate, and study biomechanical STS movement. The fuzzy model combines two local linear models defined at the initiation and termination points of STS using Gaussian membership functions that operate on measurement of knee flexion. Further, we develop TSK fuzzy controllers that employ H2 and H∞ optimal control techniques for effective regulation of biomechanical STS. The fuzzy controllers similarly combine knowledge from local linear optimal controllers via membership functions. Our simulation results show that fuzzy TSK modeling is useful for the synthesis of STS movement because of its relevance with physiological principles and the use of localized control strategies for the joint torques.

Keywords: Biomechanical model, TSK fuzzy model, optimal control, sit-to-stand movement

DOI: 10.3233/IFS-2012-0632

Journal: Journal of Intelligent & Fuzzy Systems, vol. 25, no. 1, pp. 247-258, 2013