Motion control to phase variable filter

In recent years, using phase variable filter, measurement method to analyze spectral property of the atmosphere component of the blood is studied. Then, the value of the interferogram fluctuates by the influence of the disturbance, therefore in this case where the correct spectral characteristics cannot be acquired. In this paper, our control method estimates the disturbance input to the phase variable filter by the disturbance observer and then control the motion of the movable mirror of the phase variable filter by controlling the piezo actuator. Finally, through experiment, we show the validity of our proposed method.