Stability of the non-conduct conveyance control system with self-identification function

Abstract

Sufficient stabilization effect of the implemented PID controller was confirmed by a comparison with the robust control system. The implemented PID controller was automatically designed on-line by the self-identification function of the non-contact conveyance system. The conveyance system is constructed of the three-axis (XYZ-orthogonal axis) stage and the electromagnet, both of them were manufactured for this study. The three-axis are all controlled by the three AC-servo motors respectively and precisely by using the new type of PLC (Programmable Logic Controller) named Sysmac NJ, manufactured by Omron Corporation. The electromagnet with an embedded displacement sensor is attached to the three-axis stage to be able to move just above a levitation object. The Z-axis (vertical axis) moves automatically to execute the self-identification of the parameters which are necessary to design the PID controller for the magnetic levitation control system. On the other hand, the robust controller was designed off-line by using a new model named FNFR (Finite Number Frequency Response). The robust controller was also implemented in the non-contact conveyance system to compare and make sure the stability of the PID control system. An experimental result shows the effectiveness of the proposed design method.