On the Control of a Dielectric Elastomer Artificial Muscle With Variable Impedance. Palli, G. & Berselli, G. In ASME 2013 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2013, pages V001T03A042, sep, 2013. ASME.
On the Control of a Dielectric Elastomer Artificial Muscle With Variable Impedance [link]Paper  On the Control of a Dielectric Elastomer Artificial Muscle With Variable Impedance [pdf]Paper  doi  abstract   bibtex   
Artificial Muscles based on Dielectric Elastomers (DE) can potentially enable the realization of bio-inspired actuation systems whose intrinsic compliance and damping can be varied according to the task requirements. Nonetheless, the control of DE-based Variable Impedance Actuators (VIA) is not trivial owing to the non-linear viscoelastic response which characterizes the acrylic dielectrics commonly employed in practical devices. In this context, the purpose of the present paper is to outline a novel strategy for the control of DE-based VIA. Although the proposed methodology is applicable to generic DE morphologies, the considered system is composed of a couple of conically-shaped DE films in agonistic-antagonistic configuration. Following previously published results, the system dynamic model is firstly recalled. Then, a DE viscoelasticity compensation technique is outlined together with a control law able to shape the DE actuator impedance as desired. The operative limits of the system are explicitly considered and managed in the controller by increasing the operating DE actuator stiffness if required. In addition, the problem of model uncertainties compensation is also addressed. Finally, as a preliminary step towards the realization of a practical DE-based VIA, the proposed control approach is validated by means of simulations. Copyright © 2013 by ASME.

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