Meeting Abstract

66.4  Thursday, Jan. 6  SARCOMOVER: Towards a sarcomere inspired linear actuator NELSON, RL*; UYENO, TA; WHEELER, MD; YEO, SH; WILKINSON, KC; PAI, DK; NISHIKAWA, KC; Northern Arizona University; Northern Arizona University; Northern Arizona University; University of British Columbia; Northern Arizona University; University of British Columbia; Northern Arizona University rln34@nau.edu

Here, we present a novel and efficient linear actuator design inspired by the “winding filament” model of active muscle contraction. This model is similar to the traditional sliding-filament ,swinging cross-bridge model. However, in the winding filament model, the cross bridges not only translate, but also rotate the thin filaments. This rotation serves to wind titin on the thin filaments, storing elastic potential energy during isometric contraction. Binding of PEVK titin to thin filaments prevents unwinding, so that the stored energy can be recovered during shortening. By regulating the rate of recovery of elastic energy from titin in a load-dependent manner, the cycling cross-bridges endow active muscle with intrinsic stability to perturbations in load. The winding filament model also neatly accounts for enhancement of force with stretch and depression of force with shortening. Our goal was to build an actuator prototype, inspired by the model, which exhibits these desirable features. Our patented device uses two electric motors that are controlled by an embedded microcontroller. One motor controls stiffness of a parallel elastic element (emulating the winding function of cross bridges), and the other controls length (emulating the translational function). Preliminary results indicate that inclusion of a tunable parallel elastic element within a linear actuator increases the efficiency of the device when used in repetitive motions, and this efficiency is maximized when the control parameters of the motors are similar to the load-dependent stiffness of active muscle. Supported by NAU TRIF Fund for Biotechnology.