Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchirappalli 620015, Tamilnadu, India.
ISA Trans. 2014 Mar;53(2):289-97. doi: 10.1016/j.isatra.2013.11.002. Epub 2013 Dec 6.
There is a growing trend towards miniaturization, and with it comes an increasing need for miniature sensors and actuators for control. Moreover situations occur wherein implementation of external physical sensor is impossible, here self-sensing lends its hand appropriately. Though self-sensing actuation (SSA) is extensively studied in piezoelectric, exploring this property in shape memory alloy is still under study. A simple scheme is developed which allows differential resistance measurement of antagonistic shape memory alloy actuated wires to concurrently sense and actuate in a closed loop system. The usefulness of the proposed scheme is experimentally verified by designing a one link manipulator arm and is performed in a real time tracking control. In a practical implementation of the self-sensing actuator a newly proposed signal processing electronic circuit is used for direct differential resistance feedback control upto a bandwidth of 1.8 Hz. The control design uses fuzzy PID which requires no detailed information about the constitutive model of SMA. At an operating frequency of 1 Hz, the result of the self-sensing feedback control with an angular tracking accuracy of ±0.06° over a movement range of ±15° is demonstrated.
目前，微型化的趋势日益明显，这就需要越来越多的微型传感器和执行器来进行控制。此外，在某些情况下，外部物理传感器的实现是不可能的，这时自感测就派上用场了。虽然在压电材料中已经广泛研究了自感测驱动（SSA），但在形状记忆合金中探索这种特性仍在研究中。本文提出了一种简单的方案，允许对反作用形状记忆合金致动线进行差动电阻测量，以在闭环系统中同时进行感测和驱动。通过设计一个单连杆机械手臂并在实时跟踪控制中进行实验验证，证明了所提出方案的有效性。在自感测执行器的实际实现中，使用了新提出的信号处理电子电路，用于直接差动电阻反馈控制，带宽可达 1.8 Hz。控制设计使用模糊 PID，不需要 SMA 的本构模型的详细信息。在 1 Hz 的工作频率下，演示了在 ±15°的运动范围内进行±0.06°的角度跟踪精度的自感测反馈控制的结果。
