DOI: 10.3724/SP.J.1219.2013.00664

Information and Control (信息与控制) 2013/42:6 PP.664-669

A New Compensation Method for Valve Stiction in Control Loop

Valve stiction as a nonlinear fault in process industries will lead oscillation in the control loop. For valves equipped with locators, a new compensating method, based on the transfer function of process and the set point of the loop, is proposed to reduce oscillations. Firstly, the desired position output of the valve in steady state is calculated according to the set point of the control loop, and the current output of the valve is monitored. After that, the desired steady state and the current state of valve are taken as an input to generate the compensation signal to adjust the input of the valve, which eventually turns the sticky valve to the desired steady state. In order to guarantee the algorithm compatible with different set points, the input signal to the controller is also compensated. Two practical process feedback loops with stiction are finally used to verify the effectiveness and robustness of the proposed compensating algorithm.

Key words:process industry,valve,stiction,compensation

ReleaseDate:2015-04-15 18:52:36

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