广义最小方差自校正重置PID控制器及其在压力系统中的应用研究

Generalized Minimum Variance Self-tuning Reset PID Controller and its Application in the Pressure System

针对压力系统的纯延迟、大惯性、非线性、时变等特点,本文将重置控制和以广义最小方差为性能指标的自校正PID控制相结合,提出一种广义最小方差自校正重置PID控制方法。该方法首先根据被控对象的数学模型,以广义最小方差为目标设计广义最小方差控制器,通过选择该控制器的分母多项式,求解Diophantine方程,得到具有PID结构形式的广义最小方差控制器,再在该控制器的积分项中引入重置控制,构成广义最小方差重置PID控制;对于模型未知或参数慢时变的被控对象,通过采用带遗忘因子的递推最小二乘法构建系统的自适应机制,增强控制系统的自适应能力和鲁棒性。最后,将该控制方法应用于压力容器的恒值控制中,获得了比较满意的控制效果。

Aiming at the pressure system with dead time, big inertia, nonlinearity and time variability, this paper propo ses a generalized minimum variance self-tuning reset PID control strategy by combining reset control and self-tuning PID al- gorithm. Firstly, a generalized minimum variance controller is designed according to the mathematical model of controlled plant . Secondly, a generalized minimum variance PID controller is got by reasonably selecting denominator polynomial of the above-mentioned controller and solving Diophantine equation. Thirdly, a generalized minimum variance reset PID controller is formed by introducing reset control in integral element. If the mathematical model of controlled plant is unknown or its pa rameters are varied with time, an adaptive mechanism is established by using recursive least square with forgetting factor. The mechanism can reinforce the adaptive ability and robustness of control system. Finally, the above-mentioned control strategy is applied to a constant pressure control system, a satisfactory control effect is gained.