“…In this paper, an effective method of reducing energy consumption in driving SMA actuators by using Pulse-Width Pulse-Frequency (PWPF) modulation is proposed. Though there are other type of modulators, such as psuedorate modulator (Millar and Vigneron, 1976) and integral-pulse frequency modulator (Clark and Franklin, 1969;Hablani, 1994), the PWPF modulator (Bittner et al, 1982;Wie and Plescia, 1984;Anthony et al, 1990;Song et al, 1999) holds several superior advantages such as close to linear operation, high accuracy, adjustable pulse-width and pulse-frequency, and fuel efficiency when applied to thruster systems for spacecraft. Pulse-width modulation for controlling SMAs has been reported (Honma et al, 1984;Kato et al, 1999), however, controlling SMAs using PWPF modulator is not found in the literature.…”