This requires only a constant supply voltage, and so a bulky prog

This requires only a constant supply voltage, and so a bulky programmable power supply can be replaced by very small IC chips that are more suited for miniature applications. The PWM signal is also employed for controlling the SMA actuator displacements.The selleck screening library Section selleckchem 2 of the paper describes the experimental setup for the proposed control scheme. Section 3 explains the self-sensing property of the SMA actuator. Modeling of the SMA actuator is described in Section 4. The proposed scheme of tracking control based on self-sensing feedback and inverse hysteresis compensator is described in Section 5. Section 6 shows the experimental results. Finally, the conclusions are given in Section 7.2.

?Experimental SetupThe main components of the experimental setup (a test platform and an electric circuit) are shown in Figure 1.

The test platform was used to investigate the characteristics of a bias-type SMA Inhibitors,Modulators,Libraries wire actuator (the SMA wire contracts when heated, and it expands with the aid of the bias spring when cooled). A 167-mm-long NiTi-based SMA actuator with a diameter of 150 ��m (BMF150, TOKI) was installed on the test Inhibitors,Modulators,Libraries platform. One of the ends of the SMA actuator was fixed to the platform while the other end was connected to a moving slider. A pair of linear guides restricted the slider to move only in one dimension horizontally. The linear bias spring provided a restoring force to the SMA actuator. In addition, an LED displacement sensor (OMRON) was integrated to measure the displacement of the SMA actuator.

Inhibitors,Modulators,Libraries Note that the displacement sensor was used in this study simply to Inhibitors,Modulators,Libraries validate the Inhibitors,Modulators,Libraries control results, and not to provide a feedback signal to the controller.Figure 1.Experimental setup.A schematic of the electric circuit is shown in Figure 2. A multifunction data acquisition card (��5 V full-scale range, 12-bit resolution; Inhibitors,Modulators,Libraries PCI-1711, Advantech) was employed to send the PWM signal via the digital output and measure the amplified voltage Vamp Inhibitors,Modulators,Libraries via Cilengitide the analog input. Inhibitors,Modulators,Libraries A Darlington driver IC (ULN2003AP) was used as a switching element to control the heating or cooling state of the SMA actuator. A DC voltage source Vs was connected to the selleck chemical 17-AAG SMA actuator to supply a DC voltage to heat the SMA actuator.

A resistor, R, was connected serially to the SMA actuator to prevent it from overheating. VCE of the Darlington driver was then amplified by a differential amplifier to enlarge its variation due to the electric-resistance variation of the SMA actuator during the Brefeldin_A phase transformation process. The amplified voltage Vamp was measured by the data acquisition card.Figure 2.Schematic of selleck bio the electric circuit.3.?Self-Sensing Property of SMA ActuatorFigure 3 shows the relationship between the PWM signal that inputs to the Darlington driver and the measured Vamp.

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