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- M. A. Akgun, C. Tutcu, A. Ozdemirli, "Design of a Live Muscle Tissue Actuated Mechatronic Device", 7th World Congress of Biomechanics, Boston, Massachusetts, July 6 - , 2014.
Biological components integrated mechatronic system design is an innovative method in biomechanics, recently introduced in the literature. Such hybrid systems, namely, biomechatronic devices utilize the benefits of biological components to cope with complex engineering problems in medicine as well as in energy-efficient engineering systems. A swimming robot, actuated by two frog muscles was built and tested by Herr et al. The robot remained active for up to 42 hours during which time it performed basic swimming maneuvers. However, current biomechatronic devices need significant developments to serve as reliable engineering solutions. The ultimate goal of the project is to present a proof of concept for a live-muscle-actuated mechanical/ mechatronic hybrid system. A prerequisite to design such biomechatronic systems is to acquire the ability to control the mechanical output of the muscle. As an interim work, electrically stimulated Gastronemius muscle from Rana Esculenta frog is characterized under in vitro culture conditions. All muscle specimens extracted under the approval of Yeditepe University Ethics Committee. A signal generator embedded muscle testing apparatus has been designed and manufactured for characterization purposes that allows to measure contraction force and velocity while maintaining proper culture conditions. Specimens are held in Ringer’s solution at 27 C with a constant rate of oxygen supply during the test. Characterization parameters include peak force, response time, the effect of muscle fatigue on contraction force and the effect of in vitro culture conditions on force production capability for following stimulation signal parameters: frequency, amplitude (voltage) and pulse width. Since individuals have dissimilar muscle architectures, drawing a general conclusion for muscle characterization would be highly misleading. However, experimental studies emerged significant results such as boundaries of characterization parameters and the necessity to use a closed loop control strategy rather than open loop. A mathematical model, representing individualistic behavior of a specimen is fit to the experimental data. This model is used to investigate the performance of different control strategies, since it reduces the number of experimental trials, thus the number of animals to be used. As a result, selecting PID and pulse width as the controller variable appears to be the most beneficial method for our purpose. Future work will cover testing the live muscle tissue actuated mechanism with a PID controller. The presentation in the conference will report test results in terms of controller performance, system’s efficacy and lifespan.