一种改进的鲁棒分散PID控制器的设计

Modified Robust Decentralized PID Controller’s Design

针对复杂的多变量化工过程控制,通过对有效传递函数方法的改进,得到了一种鲁棒性较高的多变量分散PID控制器设计方法METF(改进的有效传递函数法)。在有效传递函数方法的基础上,首先导出了多变量FOPTD(一阶加纯滞后)和SOPTD(二阶加纯滞后)对象的传递函数到状态空间表达式的一种转换通式;再由多变量PID控制系统的结构的统一性,推导出整个系统的闭环状态空间表达式,便于求取各种综合性能指标,并在此基础上对PID整定公式中的幅值裕度进行多目标NLJ寻优;最后利用完整性判据鉴定参数整定结果。仿真实例证实了改进方法的有效性,鲁棒性和通用性。

Aiming at the complex multivariable chemical process control, and with some improvements of the effective transfer function method, a multivariable decentralized PID controller＇s design method with high robustness was provided, which is called METF （modified effective transfer function method）. Based on the effective transfer function method, firstly, the formulas transferred from multivariable FOPTD（first order plus time delay） and SOPTD（seeond order plus time delay） processes＇ transfer function to state space representation are obtained; then according to the unified structure of multivariable PID control system, the close-loop＇s state space representation of the whole system was obtained, which is quite useful to calculate various kinds of integrative performance index, and do the multi-goal NLJ optimizing of gain margin in PID parameter tuning formula. Lastly, the tuning results＇ reliability was checked up by the integrality criterion. Several simulation examples demonstrate the effectiveness, robustness and universality of the modified method.