Durante Francesco, Raparelli Terenziano, Beomonte Zobel Pierluigi
Department of Industrial and Information Engineering and Economy (DIIIE), University of L'Aquila, P.le Pontieri 1, Località Monteluco, 67100 L'Aquila, Italy.
Department of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
Micromachines (Basel). 2024 Apr 18;15(4):545. doi: 10.3390/mi15040545.
This paper illustrates an experimental activity for the closed-loop position control of an actuator made using shape memory alloy (SMA) wire. A solution with the self-sensing effect was implemented to miniaturize the systems, i.e., without external sensors. A proportional control algorithm was initially used, demonstrating the idea's feasibility; the wire can behave simultaneously as an actuator and sensor. An experimental investigation was subsequently conducted for the optimization of the developed actuator. As for the material, a Flexinol wire, Ni-Ti alloy, with a diameter of 0.150 mm and a length of 200 mm, was used. Preliminarily, characterization of the SMA wire at constant and variable loads was carried out; the characteristics detected were elongation vs. electric current and elongation vs. electrical resistance. The control system is PC based with a data acquisition card (DAQ). A drive board was designed and built to read the wire's electrical resistance and power it by pulse width modulation (PWM). A notable result is that the actuator works with good precision and in dynamic conditions, even when it is called to support a load up to 65% different from that for which the electrical resistance-length correlation has previously been experimentally obtained, on which the control is based. This opens up the possibility of using the actuator in a counteracting configuration with a spring, which makes hardware implementation and control management simple.
本文阐述了一项针对采用形状记忆合金（SMA）丝制成的执行器进行闭环位置控制的实验活动。采用了一种具有自感知效应的解决方案来实现系统的小型化，即无需外部传感器。最初使用了比例控制算法，证明了该想法的可行性；该丝可同时充当执行器和传感器。随后进行了实验研究以优化所开发的执行器。至于材料，使用了直径为0.150毫米、长度为200毫米的Flexinol丝（镍钛合金）。首先，对SMA丝在恒定和可变负载下进行了特性表征；检测到的特性是伸长量与电流以及伸长量与电阻的关系。控制系统基于带有数据采集卡（DAQ）的个人计算机。设计并制作了一个驱动板，用于读取丝的电阻并通过脉宽调制（PWM）为其供电。一个显著的结果是，即使在被要求支撑的负载与先前通过实验获得的电阻 - 长度相关性所基于的负载相差高达65%的动态条件下，该执行器仍能高精度工作。这为在与弹簧的抵消配置中使用该执行器开辟了可能性，这使得硬件实现和控制管理变得简单。
