偏置弹簧对SMA驱动器输出性能影响规律

偏置弹簧参数对形状记忆合金(SMA,Shape Memory Alloy)驱动器的输出性能有着非常大的影响.为获得其影响规律,通过试验研究了不同偏置弹簧刚度以及不同弹簧预压缩载荷下,SMA驱动器的作动位移、响应速度的变化规律以及循环次数对驱动器性能的影响规律.试验结果表明,驱动器最大作动位移及响应速度随弹簧刚度或预载的增大而降低;驱动器性能在前几次循环中衰减较大,随着循环进行性能逐渐趋于稳定;弹簧预载的增大使驱动器性能稳定所需的循环次数减少,而弹簧刚度对驱动器输出性能的循环变化规律影响不大.

Relationship between bias spring parameters and output performances of SMA actuators

The parameters of the bias spring have great impacts on the output performances of the shape memory alloy (SMA) actuator. To investigate the rules of influences, the output stroke and response rate of a SMA actuator with different bias spring stiffness and precompression load were studied. The output degradation due to cyclic actuation was also investigated. Experimental results show that the strokes and response rates decrease with the increase of preloads or stiffness. The performance of the actuator degrades significantly in the first few cycles and stabilizes eventually with the increase of the number of cycles. The test results also indicate that less cycling is needed to stabilize the actuator when the preload is increased, and the stiffness seems to affect the cyclic performance of the actuator slightly.