Estimação e compensação da histerese em válvulas de controle pneumáticas

Abstract

In this work are discussed methods for diagnosis, quantification and compensation of backlash in pneumatic control valves. The backlash is measured through offline methods known in the literature and it is compared with on-line method, showing similar results with both methods. Tests are done via simulation of mathematical models known from literature and with a valve on a real working process. Backlash is computed and its effect is compensated in the control loop, reducing the variability of the process variable. The static friction is estimated by the offline method, and in the on-line method it is estimated together with the backlash. The results in simulation and in real tests show that the estimation of the backlash followed by the compensation can reduce the output fluctuations of the process, the value of the IAE index and the number of reversals of the valve.