Grating Angle Encoder Detection Control System Design

The detection device of optical lever angle encoder is used for error detection of angle encoder,which can improve the precision of motion control.Angle detection devices play an important role in the fields of industry,scientific research,military industry and so on.In order to improve the detection accuracy of angle measuring device,researchers at the Yunnan Observatory,Chinese Academy of Sciences put forward the use of optical level converting small angle to small displacement,and gain the changing accurate measurement value of position changing in facula through high precision positioning to the image of facula,Through detecting and correcting the measurement value in measuring device angle,which is a method that can obtain high angle measurement precision through low cost.The detection device of optical lever angle encoder needs high precision rotation control,and automatic detection.According to the moving mechanism of control system,and logical requirement of realizing motion in optical angular encoder,chose an open motion control system,which system uses "the computer and PMAC motion control card" mode.The hardware part:computer logic control unit,the PMAC motion control card execution unit,a stepper motor control element driving device with a worm,the data encoder as the feedback element,high precision position control of double turntable.The part of the software design of the computer incorrding VC++,which designs upper-position computer interface,that can make the whole system simple,feasible and strong portability;and on the basis of the integral separation PID control algorithm and the effective feedforward control of PID parameters tuning.The application software of the control system is programmed to realize the synchronization between the CCD exposure and the data acquisition of the encoder.The control interface includes the basic operation of rotary table,the return to zero,the speed regulation,the real-time position,speed and follow error information display of the upper and lower turntable,which can realize the automatic detection mode.and the real time displaying and saveing.The PLC program is written by Pewin32 PR02 software to realize the data acquisition and data acquisition of CCD camera.After the system built,it makes a test of the error in turnable positioning.which contains the stability of sports system,dual turntable concentricity,code level reading head installation.The final experimental results show that the repeatability error of the absolute value of the turntable device is less than 4 ",meet the angle coding detection system decoder,stable performance good.The project in this paper is funded by the National Natural Science Foundation of China(U1331109).