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为了解决目前工业系统中普遍使用的PID控制器由于工况变化等原因引起的系统发生时变而导致所在回路PID控制器性能可能下降的问题,本文提出了一种专门针对PID控制器进行性能评估、优化及监控的方法,即:PID循环评估优化算法。该算法利用系统闭环输入输出数据,使用基于MVC(minimum variance control)的PID最小方差准则,来对PID控制器的性能进行评估,并且计算出在最小方差意义下最优PID控制器参数;评估过程结果与现实系统输出方差进行比较,做为PID参数在线优化的判断依据,当现实系统性能低于某一标准的时候对控制器进行优化处理。在整个算法中,通过输入输出数据的处理与判断,利用评估优化后的PID参数对系统进行控制,并再次回到最初的输入输出数据的处理和判断过程,实现在控制过程中的系统性能监控。本文的计算机仿真试验验证了该方法的有效性,由图可看出,系统发生渐变和突变后,当输出方差超过了程序限定的标准时,在1 300秒内系统能自动评估并施行优化而达到稳定。该循环评估优化算法现实了在对系统进行性能评估监控的同时,能按照一定条件作为标准对系统的PID参数进行优化,最终使得系统具有自我监控评估和自我优化的能力,此方法能在特定的工况下进行应用。
In order to solve the problem that the performance of the PID controller in the current loop may be degraded due to the time-varying system caused by the change of the operating conditions of the commonly used PID controller in the industrial system, a method of evaluating the performance of the PID controller , Optimization and monitoring methods, namely: PID cycle evaluation optimization algorithm. The algorithm uses the closed-loop input and output data of the system to evaluate the performance of the PID controller by using the PID minimum variance rule based on minimum variance control (MVC) and calculates the optimal PID controller parameters in the sense of minimum variance. The evaluation process The results are compared with the actual system output variance as the basis for judging online optimization of PID parameters. When the real system performance is lower than a certain standard, the controller is optimized. Through the processing and judgment of input and output data, the whole algorithm is used to control the system by evaluating and optimizing the PID parameters, and once again, it is returned to the process of processing and judging the initial input and output data to realize the system performance monitoring in the control process . The computer simulation of the paper verifies the effectiveness of this method. It can be seen from the figure that after the system has gradual and abrupt changes, when the output variance exceeds the standard defined by the program, the system can automatically evaluate and optimize it within 1 300 seconds stable. The loop estimation optimization algorithm realizes the system performance evaluation in the monitoring of the same time, according to certain conditions as a standard PID parameters to optimize the system, and ultimately make the system has the ability to self-monitoring assessment and self-optimization, this method can be in a specific Application conditions.