Hysteresis Modeling of SMA Actuators for Control Applications

Abstract

Active material actuators, sometimes referred to as "smart" actuators, are gaining widespread use for control actuation. Many of these actuators exhibit hysteresis to some degree between their input and output response. There exists an extensive body of research concerning the modeling of hysteresis for the linearization, or compensation, of these hysteresis nonlinearities. However, the models have typically been identified off-line and mainly used in open-loop compensation. When the identified models do not exactly match the actuator nonlinearities, the compensation can create an error between the desired and actual control output. The hysteresis for several of these actuators has been shown to evolve over time, and can render a fixed hysteresis model inadequate to linearize the hysteretic nonlinearities. This paper presents an adaptive hysteresis model for on-line identification and closed-loop compensation. Laboratory experiments with a shape memory alloy wire actuator provide evidence of the success of the adaptive identification and compensation. In addition, the means of determining the saturation of the SMA using updated information from the adaptive hysteresis model is provided.

Modeling, Compensation and Control of Smart Devices with Hysteresis

“…Similar conclusions can be drawn for Shape Memory Alloys (SMA) which show huge deformations driven by temperature variations and therefore are generally quite slow [45]. The Ni-Mn-Ga materials, also referred to as Ferromagnetic Shape Memory Alloys (FSMA), [40] overcome this limitation still preserving high deformations as SMAs.…”

Modeling and control of hysteresis in magnetostrictive actuators

“…To combat this problem, one approach is adaptive inverse control (Tao & Kokotovic, 1995;Webb et al, 1998;Kuhnen & Janocha, 1999). In this paper we explore an alternative approach and develop a robust control framework for magnetostrictive actuators.…”

Hysteresis Behaviour and Modeling of SMA Actuators

“…The rest of this section only covers the main principles of this theory. A more complete description is available elsewhere (Mayergoye, 1991;Krasnoselskii et al, 1994;Webb & Lagoudas, 1998).…”