Large-caliber telescope non-linear interference detecting and filtering method

A method to detect and filter large-caliber telescope non-linear interference, the method comprising the following steps:

• (1) determining if an oil pad interference is accomplished with one or both of an accelerometer method and an encoder method;
• wherein, the accelerometer sensor method includes:
• (1)-1. setting an accelerometer at a base of a telescope azimuth shaft;
• and setting an additional accelerometer at a gear oil diverter of an oil pad;
• (1)-2. inputting signals of the accelerometer and the additional accelerometer into an industrial personal computer via an AD adaptor card;
• (1)-3. wherein, when the oil pad is turned off and the telescope is static, measuring the signals of the accelerometer and the additional accelerometer and plotting an acceleration vs frequency curve;
• (1)-4. wherein, when the oil pad is turned on and the telescope is static, measuring the signals of the accelerometer and the additional accelerometer and plotting an acceleration vs frequency curve;
• (1)-5. obtaining the oil pad vibration interference frequency by comparing the acceleration vs. frequency curve of step (1)-3 and the acceleration vs. frequency curve of step (1)-4;
• wherein the encoder method includes:
• (2)-1. using a photoelectrical encoder as a position sensor on the telescope azimuth shaft;
• (2)-2. inputting a signal of the photoelectrical encoder into the industrial personal computer via a photoelectrical encoder acquisition card;
• (2)-3. measuring the signal from the photoelectrical encoder with the oil pad turned off and the telescope static, continuously sampling for a period of time, and plotting an encoder data curve and a FFT (fast Fourier transformation) curve;
• (2)-4. measuring the signal from the photoelectrical encoder with the oil pad turned on and the telescope static, continuously sampling for a period of time, and plotting an encoder data curve and a FFT curve;
• (2)-5. obtaining the oil pad vibration interference frequency by comparing the acceleration curve and the FFT (fast Fourier transformation) curve;
• (3) filtering the oil pad interference frequency:
• by using a NOTCH filter and setting a NOTCH frequency at the interference frequency obtained in step (1), the interference being filtered to improve performance of the telescope.