Two-dimensional Precision Positioning System With Wide-range Based On Laser Interference

As the basis of precision machining and inspection, two-dimensional precisionpositioning system has played a very crucial role in the process of many subjects, such asmicroelectronic manufacture, Precision optical detection and processing, scanningmicroscope, biomedicine and so on. With the expansion of the processing size and detectionrange, technology of two-dimensional precision positioning system with wide-range isbecoming a hot research area.In order to realize two-dimensional positioning and scanning in a with wide-range, atwo-dimensional precision positioning system with good repeatability is developedcombining laser interferometer, aerostatic guideway with pipeline channeling off used air,precision ball-screw and servo control system. The system use laser interferometer aslength measuring standard, with the support of environmental compensation system,location information of the X-axis and Y-axis is fed back by laser interferometer in realtime. Using aerostatic guideway with pipeline channeling off used air overcome theresidual air influence on laser interference measurement optical path system in traditionalgas float guideway. PID control technology is applied in the process of positioning, thesystem has fast and smooth response characteristics by adjusting PI parameters of the servocontroller. At the same time, the control software, based on VC++6.0, is designed to realizetwo-dimensional precision positioning and scanning. This paper discusses the followingcontents:1. The principle and overall scheme of the two-dimensional precision positioningsystem. Based on the principle of precision positioning, this paper first introducedperforming machine, driving method and feedback mode respectively. It include theprinciple and improvement of the aerostatic guideway with pipeline channeling off used air,modle selection of precision ball screw and servo motor, optical path structure design oflaser interferometer and environmental compensation system.2. The control technique of precision positioning and two-dimensional scanning. Itcovers the introduction of PID control theory, adjust the PI parameters of the Yaskawaservo controller, the closed-loop control method used in precision positioning, equally spaced sampling method and equal time intervals sampling method used intwo-dimensional scanning.3. The control software, based on VC++6.0. Analysze the component of the controlsystem, introduce the multi-thread technique and event trigger mechanism used in thesoftware.4. The experiment of two-dimensional precision positioning system. The experimentsystem is established to measure the bidirectional accuracy of positioning and repeatabilityof the system, also the linear grating is scanned to test the feasibility of the measurementand control system.