Dynamic matrix control (DMC) engineering method based on model simplification and prediction error correction

A technology of error correction and model simplification, which is applied in the direction of instruments, adaptive control, control/adjustment systems, etc., can solve the problems of system accuracy and robustness degradation, difficulty in realizing bottom-level control, and inability to apply DMC, etc., and achieve control law simplification , online calculation and memory usage are reduced, and the effect of timely correction

Inactive Publication Date: 2012-03-28
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The purpose of the present invention is in order to solve existing one, the process of some fast control, can not apply DMC; Two, with the DMC of instant error correction delay, index is affected in predictive control; Decrease in accuracy and robustness; 4. It is difficult to realize the underlying control problem, providing a DMC engineering method based on model simplification and forecast error correction

Method used

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  • Dynamic matrix control (DMC) engineering method based on model simplification and prediction error correction
  • Dynamic matrix control (DMC) engineering method based on model simplification and prediction error correction
  • Dynamic matrix control (DMC) engineering method based on model simplification and prediction error correction

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specific Embodiment approach 1

[0021] Specific implementation mode one: combine figure 1 Describe this implementation mode, the concrete steps that this implementation mode comprises are as follows:

[0022] Step 1. Measure the step response curve of the system; establish a model with an order of N, divide the whole step process into N equal parts according to time, N is a natural number, and the selection of N includes all dynamic processes;

[0023] Step 2. Simplify the model obtained in step 1 to obtain a simplified model. The specific process is: reduce the order of the model to n, n<

[0024] Step 3, the rolling optimization control of the simplified model; obtain the simplified model and the actual system error sequence {e(k)};

[0025] Step 4, establishing a forecast error model; establishing an AR model through the error sequence {e(k)};

[0026] Step 5. Judging whether the AR model established in st...

specific Embodiment approach 2

[0028] Specific implementation mode two: the specific process of step one in the implementation mode one is:

[0029] The predictive control of DMC is based on the step response sequence a 1 , a 2 ,...a N , related to the sampling period,

[0030] DMC consists of expressions (1) to (3): Y m (k+1)=AΔU(k)+A 0 U(k-1) (1)

[0031] A,A 0 matrix by a 1 , a 2 ,...,a N constitute;

[0032] Y p (k+1)=AΔU(k)+A 0 U(k-1)+he(k) (2)

[0033] e(k) is the error between the actual output and the model output,

[0034] ΔU ( k + i - 1 ) = D i T [ Y r ( k + 1 ) - A 0 U ( k - 1 ) ...

specific Embodiment approach 3

[0038] Specific implementation mode three: the process of establishing a simplified model in step two in the first implementation mode is aimed at A in the model 0 U(k-1) performs simplified dimensionality reduction, the specific process is:

[0039] The system model uses G(z -1 ) = g 1 z -1 +g 2 z -2 …+g n z -n …+g N z -N (4)

[0040] expression, where g 1 =a 1 , g i =a i -a i-1 , i=2, 3,...N;

[0041] For the over-damped self-balancing object, that is, g in formula (4) n z -n The subsequent items can be processed according to exponential decay, so formula (4) is approximated as formula (5) G ( z - 1 ) = g 1 z - 1 + g 2 z - 2 ...

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Abstract

The invention discloses a dynamic matrix control (DMC) engineering method based on model simplification and prediction error correction, which relates to the DMC engineering method and solves the existing problems as follows: (I) DMC cannot be applied in certain rapid control processes; (II) the indexes of the DMC for instant error correction lag are influenced in predictive control; (III) although the real-time performance is improved by the model simplification, but the precision and the robustness of the system are reduced; and (IV) bottom control is hard to realize. The DMC engineering method based on the model simplification and the prediction error correction comprises the following concrete steps: (I) acquiring the step response curve of the system, and establishing a model of which the order is N; (II) simplifying the model, and reducing the order of the model to n; (III) simplifying the rolling optimal control of the model; (IV) establishing a prediction error model; (V) judging whether model testing passes or not; if the model testing does not pass, returning to the step (IV); and if the model testing passes, executing the comprehensive control of the model simplification and the prediction error correction; and (VI) judging whether a control effect reaches the requirement or not; if the control effect does not reach the requirement, returning to the step (II); and if the control effect reaches the requirement, enabling the control effect to be used for control. The DMC engineering method based on the model simplification and the prediction error correction is used for DMC engineering control.

Description

technical field [0001] The present invention relates to DMC engineering methods. Background technique [0002] Predictive control is mainly composed of three parts: predictive model, rolling optimization control and error correction. DMC (Dynamic Matrix Control) is a predictive control method widely used in industrial process control. DMC has the following four problems in practical application: [0003] 1. The DMC prediction model is a step response non-parametric model, and N parameters need to be extracted from the complete dynamic process of the step response, and N is generally about 50; therefore, the real-time performance of the control algorithm is reduced, and for some fast control processes, DMC cannot be applied; [0004] 2. DMC uses error correction, but predictive control is mainly aimed at objects with a large time delay, while DMC uses immediate error correction to delay objects, and the control indicators of the system will be affected; [0005] 3. At pres...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G05B13/00
Inventor 邓盛川齐维贵
Owner HARBIN INST OF TECH
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