形状记忆合金丝致动器新型电热方法及其建模与实验研究

Modeling and Experimental Study on a New Electric-thermal Heating Method for Shape Memory Alloy Wire Actuators

针对较粗形状记忆合金(SMA)丝致动器电阻小、通电加热困难的问题,提出一种在SMA丝表面缠绕漆包线的新型复合加热方法。采用集总参数法,并将螺旋缠绕的漆包线与SMA丝之间复杂的热交换过程简化描述为等效热导率,建立了该电热驱动过程的热力学模型。该模型所得的计算结果与实验测试结果的对比分析表明,所建立的热力学模型可以准确地描述该电热驱动方法的加热和冷却过程。实验还进一步表明,漆包线和SMA丝同时通电加热,可大幅提高SMA丝致动器的升温速率。

Aimed at the electric-thermal heating difficulties of thick SMA wire actuators for their small resistance,a new type of composite electric-thermal heating method by winding the enameled wire around the SMA wire was presented.Using the lumped parameter method and simplifying characterization of the complex heat exchange process between the enameled wire and the SMA wire to an equivalent thermal conductivity,a thermodynamic model of this electric-thermal heating process was built.And comparative analysis between the numerical solution of this theoretical model and the experimental results demonstrates that this thermodynamic model can describe accurately the heating and cooling process of this electric-thermal heating method.Further experiments show that this electric-thermal heating method can increase greatly the thermal heating velocities of thick SMA wire actuators.