Positioning control of the finger tip drive type of linear stage using disturbance observer

This paper purposes to improve accuracy of positioning control within nano-scale of the linear stage made of fine-ceramics. In this control, the disturbance as the vibration of the tip and the friction transition between the tips and the guide causes the position vibration of the stage, and then the position error is increased. Positioning control of the linear stage is examined by two control strategies, i.e., a PID control (PID type) and a PID control with the disturbance observer (PID+DO type). Comparing the experimental results, it is found that the position error of PID+DO type is less than that of PID type. The considerations in the comparison for the experimental data are shown.