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arXiv · 2207.13841

System Identification and Two-Degree-of-Freedom Control of Nonlinear, Viscoelastic Tissues

Amanda Bianco·Raphael Zonis·Anne-Marie Lauzon·James Richard Forbes·Gijs Ijpma
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Abstract

Objective: This paper presents a force control scheme for brief isotonic holds in an isometrically contracted muscle tissue, with minimal overshoot and settling time to measure its shortening velocity, a key parameter of muscle function. Methods: A two-degree-of-freedom control configuration, formed by a feedback controller and a feedforward controller, is explored. The feedback controller is a proportional-integral controller and the feedforward controller is designed using the inverse of a control-oriented model of muscle tissue. A generalized linear model and a nonlinear model of muscle tissue are explored using input-output data and system identification techniques. The force control scheme is tested on equine airway smooth muscle and its robustness confirmed with murine flexor digitorum brevis muscle. Results: Performance and repeatability of the force control scheme as well as the number of inputs and level of supervision required from the user were assessed with a series of experiments. The force control scheme was able to fulfill the stated control objectives in most cases, including the requirements for settling time and overshoot. Conclusion: The proposed control scheme is shown to enable automation of force control for characterizing muscle mechanics with minimal user input required. Significance: This paper leverages an inversion-based feedforward controller based on a nonlinear physiological model in a system identification context that is superior to classic linear system identification. The control scheme can be used as a steppingstone for generalized control of nonlinear, viscoelastic materials.

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Amanda Bianco, Raphael Zonis, Anne-Marie Lauzon, James Richard Forbes, Gijs Ijpma. 2022-07-28. System Identification and Two-Degree-of-Freedom Control of Nonlinear, Viscoelastic Tissues. https://doi.org/10.1109/tbme.2022.3179655

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