PID control parameter self-correction method based on closed-loop step response cascade loop

Abstract

The invention provides a PID (Proportion Integration Differentiation) control parameter self-correcting method based on a closed-loop step response cascade loop, and belongs to the technical field ofcascade system controller parameter setting. According to the method, closed-loop step response data of a control loop is collected, and then a series of off-line operations are carried out accordingto the closed-loop step response data to obtain a set controller parameter value, so that the condition that the normal operation of the control system needs to be interrupted when the existing controller parameter setting method corrects the controller parameters through multiple times of external excitation is avoided; and moreover, in the controller parameter derivation process, the condition that interference exists in an auxiliary loop is considered, and the parameters of an auxiliary controller are corrected by utilizing a direct analysis design principle, so that the anti-interference performance and the stability of the control loop are improved. Tests in an actual industrial application rectifying tower stripping section temperature value control system show that the method can obviously reduce the overshoot phenomenon of a cascade control system, and the fluctuation range of the control system is obviously reduced when interference is generated.

Description

technical field [0001] The invention relates to a self-calibration method for cascade loop PID control parameters based on a closed-loop step response, and belongs to the technical field of cascade system controller parameter tuning. Background technique [0002] The cascade control system is a double-closed-loop control system composed of two controllers connected in series. Among the two controllers, one is the main controller, and the variable it detects and controls is called the main variable; the other is the sub-controller. , the variables it detects and controls are called auxiliary variables, which are auxiliary variables introduced to stabilize the main variables. The cascade control system improves the control quality of the main variable by setting the auxiliary variable. Due to the existence of the auxiliary loop, it has the effect of advanced control on the disturbance entering the auxiliary loop, thus reducing the influence of the disturbance on the main varia...

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Problems solved by technology

[0006] In order to solve the problem of affecting the normal operation of the system caused by setting the parameters of the cascade control system in two tests at present, the present invention provides a cascade controller parameter self-calibration method based on closed-loop step response data. Collect the closed-loop step response data of the cascade controller applied in the controlled system, estimate the model parameters of the controlled objects of the main and secondary loops in the controlled system according to the closed-loop step response data; and then according to the estimated main and secondary loop controlled objects The model parameters of the cascade controller are used to correct the parameters of the primary and secondary loops

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