A performance evaluation method for pid control loops in tobacco processing

Abstract

The invention relates to the related technical field of tobacco processing process control, in particular to a performance evaluating method oriented to a PID control loop in the tobacco processing process. The performance evaluating method is characterized in that oriented to the PID control loop in the tobacco processing process, a blended genetic algorithm combining a genetic algorithm and a correction Newton method is proposed to optimize and calculate the minimum variance capable of being achieved by a PID controller, the situation that a traditional optimization algorithm is likely to fall into local optimization is avoided, and the local searching optimization capability of the algorithm is also improved; in addition, punishment of cost control is taken into consideration in a target function, and the changes of control action are also considered in calculation of the minimum variance, so that more objective and more efficient performance evaluating indexes are obtained, and the process control performance monitoring level is increased. By means of the method, equivalence analysis can be carried out on the series PID loop in the tobacco processing process, so that the application range of the method is effectively widened, the process control performance evaluating capability is improved, and the more objective and more efficient performance evaluating indexes are obtained.

Description

Technical field [0001] The invention relates to the related technical field of tobacco processing process control, in particular to a performance evaluation method for PID control loops in tobacco processing. Background technique [0002] Since Harris proposed to use the closed-loop output variance under the action of the minimum variance controller as the controller performance evaluation benchmark (Can J Chem Eng, 1989(67): 856-861), since then, most studies have been carried out around this benchmark, but little attention has been paid Its applicability to a specific type of controller. In the control of tobacco processing, more than 90% of the controller types are PID controllers. However, research has found that due to its own structure, even a well-tuned PID controller, its output generally cannot reach the variance under the control of the minimum variance controller. If the minimum variance control standard is used to evaluate the PID control loop, wrong and unobjective ...

AI Technical Summary

Problems solved by technology

However, this method has the following main problems in actual use: First, the traditional optimization calculation method is easy to fall into the local optimum, unable to obtain the global optimal solution, or even the optimal solution, and the calculation speed is slow; second, the output variance The objective function does not take into account the cost effect of the control

This makes the calculation of the evaluation benchmark not reflect the objective reality, which affects the rationality of performance index evaluation

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