Performance evaluation of feedback displacement control system of aerostatic thrust bearing using pneumatic servo valve

(1st report, Compensation performance against external constant loads)

Abstract

Recently, upon creating microstructure on a workpiece surface, manufacturing high value-added parts with superior characteristics such as wettability is required. These parts are machined using ultra-precision machine tools. In this case, the ultra-precision machine tools need to be equipped with a high-speed aerostatic spindle that shaft diameter is small e.g., 10 mm. Using a small diameter shaft is decreased the bearing stiffness because of decreasing the bearing area. There are many studies shown to be effective. However, it is difficult to apply to the traditional aerostatic bearing because it needs to put a special mechanism in bearings in the design phase. Therefore, the purpose of this study was to develop a feedback displacement control system that the spindle shaft can be maintained in a uniformed position. And also, we evaluated the control performance of this system against external constant loads. As a result, we found that the displacement control system has high performance.