Design And Implementation Of Intelligent Control Algorithm On DCS

Thermal production process exist many objects that is difficult to be controlled, which often have a strong big lag, strong coupling and nonlinear characteristics, so that the traditional PID control can’t be eligible to the desired control effect. The rapid development of intelligent control theory in recent years largely compensate for the lack of PID control, but in the engineering application does not get great promotion. Considering the DCS is widely used in thermal power control, the paper will study how to achieve intelligent control algorithm in the DCS from engineering practice.Firstly, the development of intelligent control were briefly discusses in this paper. Secondly, based on a self-development of the distributed control system named UCONTROL, this article introduces the structure and the technical characteristics of conventional DCS and presents how to achieve intelligent control algorithm in the configuration software in detail. This paper designs a fuzzy-PID control strategy based on expert rules. With adjustment factors using in the fuzzy controller, the number of parameters are reduced and fuzzy operation is simplified. At the same time, kind of fuzzy controller’s parameter tuning rules are given through simulation studies. Then we use the expert rules to determine the weighting coefficients between fuzzy output and PID output. The large delay object’s simulation results show that this kind of controller is much better than a simple PID control in the dynamic performance indicators and adapt to different conditions, robust, suitable for large lag process’ s control.Finally, this paper focuses on the design of an expert-fuzzy PID control algorithm’s implementation steps in UCONTROL. The fuzzy control algorithm and expert rules were packaged into two algorithm function modules in configured software. Moreover, I fully take requirements of commissioning and tracking signal when switch between automatic and manual into account. Finally, the control strategy applied to superheated steam temperature cascade control system, the DCS simulation results show the feasibility and effectiveness of this program.