基于等效传递函数的多变量大滞后系统的内模控制方法研究

Internal Model Control Method Research Based on the Equivalent Transfer Function for Multivariable Process with Large Time Delays

摘要:

针对多变量大滞后系统存在的强耦合、控制困难等问题,文章提出了一种基于等效传递函数的内模控制新方法；该方法首先给出了具有内模结构的等效传递函数的计算方法,得到系统的等效传递函数；然后采用麦克劳林降阶法对得到的高阶传递函数进行降阶,进而根据降阶后的模型设计内模控制器,有效避免了超前项的出现,降低了控制器设计的复杂性；同时,为了消除稳态误差,在内模控制器上添加了一个由系统稳态响应获取的稳态增益；仿真结果表明,该方法能能够消除系统的稳态误差,实现系统的设定值跟踪；本方法具有设计简单、控制性能好等特点。

Abstract:

For the problems of strong interaction and difficult control in multivariable process with large time delays, a new internal model control method research based on the equivalent transfer function is proposed in the paper. Computing method of equivalent transfer function with internal model structure is given firstly and the equivalent transfer function of the system is obtained. Then the McLaughlin order reduction method is adopted to get the higher order transfer function of order reduction. The internal model controller is desgined based on the reduced order model, which avoid the item in advance effectively and reduces the complexity of controller design. Simultaneously, in order to eliminate the steady state error, steady state gain is added in the internal model controller by the system steady-state response. The simulation results show that this method can eliminate the steady-state error of the system, implement setpoint of the system, having the characteristics of simple design, good control performance.