研究期間：10108~10207;In this project, we will utilize the wire-type shape memory alloy (SMA) as actuator for auto-focusing mechanism for micro cameras. Since the Nickel-titanium (NiTi) SMA "remembers" its original shapes and eventually will return to its original shapes after deformed by applying heat to it. The one-way memory effect of NiTi SMA wire can be utilized to study the feasibility of replacing conventional actuators like voice coil motor, stepping motor, and piezoelectric motor. In this first year, we will study the properties of NiTi SMA wire (0.1mm) characteristics study. This SMA wire deforms and changes its length during temperature/stress change. This is known to transition from the martensite phase to the austenite phase, or the reverse. Also in the first year, we will start to design a wedge type mechanism to transform the elongation of the wire to the movement of the lens. Since the forward and backward dynamics of this actuator will be different, the mathematical model of this system will be a switching type nonlinear system. Hence, in the second year, we will focus on developing new control algorithms for this system, and at the same time, the dynamic performance and stabilities of different control rules will be analyzed through Matlab. The control algorithms developed in the second year will be downloaded into an ARM computer and the real-time control for the auto-focusing mechanism will be carried out in the third year. The disturbances and noises will be considered in the real system and the compensation algorithms will be also developed.
