差动式电热SMA驱动器设计及驱动性能研究

The Driver Design and Drive Performance of Differential Electro-thermal SMA

根据NiTi形状记忆合金(Shape Memory Alloy,SMA)的记忆效应,设计制作了差动式电热SMA驱动器,并建立了差动式电热SMA驱动器的力学方程。在无负载状态下,实验测得驱动器驱动位移为2mm时,驱动电流随时间的变化关系。结果表明,当电流<2.5A时,随着电流的增加,驱动速率相对较低;当电流>2.5A时,随着电流的增加,驱动速率明显增加。通过对不同温度下驱动位移的测试结果及驱动器力学模型计算结果对比分析可知,只有当温度达到奥氏体相变开始温度时,才会有驱动位移。并且理论计算结果和实测结果趋于一致,从而说明了所建立的差动式双向SMA驱动器驱动力模型的正确性,可为差动式SMA驱动器的设计提供理论指导。

According to the memory effect of NiTi Shape Memory Alloy(SMA),differential electro-thermal SMA driver has been designed and manufactured,and the mechanical equation of differential electro-thermal SMA driver is established.Under no-load condition,the relationship between driving current and time is measured when driving displacement is 2 mm.The results show that when the current is less than 2.5 A,the driving speed is relatively low with the increase of the current;when the current exceed 2.5 A,the driving speed increases obviously with the increase of the current.By comparing and analyzing the results of driving displacement tests and driver mechanical models calculation at different temperatures,it can be seen that only when the temperature reaches the starting temperature of austenite transformation,there will be driving displacement,and the theoretical calculation results converge with the experimental results,which shows the correctness of the established driving force model of the differential two-way SMA driver.It can provide theoretical guidance for the design of the differential SMA driver.