Study on the backlash measurement and software compensation of basis weight control valve

The precision of the basis weight control valve, which is equipped with a planetary reducer, cannot meet the requirements of field applications because the transmission backlash was neglected. Applied technological research on backlash measurement and compensation is described in this paper. A backlash measurement experimental device was developed to measure the backlash of the basis weight control valve. Both the rotation angle of the input shaft and output shaft of the actuator were measured, and the transmission backlash was obtained. The test results from a sample with a type DN 125 mm valve showed that the average backlash value was 13.32 arcmin, the percentage was 0.247% compared to the full travel range of the valve, and the precision of the valve could only reach 405 steps if the backlash was not compensated. A software compensation method for reverse movement backlash is proposed. A number for the control pulse signal equivalent to the value of the backlash was added at the reverse moment, which was used to counteract the backlash of the transmission mechanical system. The final positioning error was 0.0181% after software compensation, and it can meet the required precision of 5, 000 steps.