Ultra-precision measurement and control of rolling of stage

The present paper describes a new system to measure and control rolling of a precision stage. In this system, the rolling of the stage is monitored by a new measuring method, and is controlled to be zero by a feedback control system. The new method utilizes two angle probes to scan the rolling angle profile of the surface of a target mirror mounted on the stage. The principle of the method is based on the absolute straightness measurement by two angle probes and the technique to evaluate and correct the zero adjustment error between two probes. The output data of the two angle sensors consist of the rolling of stage and the rolling angle profile of target minor. The rolling of stage and the rolling angle profile can then be separated from each other by using the angle sensor output data. Experimental results showed that the rolling can be measured and controlled to 0.05 s (arc) that is determined by the stability of the rolling measurement system.