1、附录 CONTROL, PID CONTROL, AND ADVANCED FUZZY CONTROL FOR SIMULATING A NUCLEAR REACTOR OPERATION XIAOZHONG LI and DA RUAN* elgian Nuclear Research Centre (SCKoCEN Boeretang 200, 8-2400 Mol, Belgium (Received 15 March 1999) Based on the background of fuzzy control applications to the first nuclear reac
2、tor in Belgium (BRI) at the Belgian Nuclear Research Centre (SCK.CEN), we have made a real fuzzy logic control demo model. The demo model is suitable for us to test and com- pare some new algorithms of fuzzy control and intelligent systems, which is advantageous because it is always difficult and ti
3、me-consuming, due to safety aspects, to do all experiments in a real nuclear environment. In this paper, we first report briefly on the construction of the demo model, and then introduce the results of a fuzzy control, a proportional-integral-derivative (PID) control and an advanced fuzzy control, i
4、n which the advanced fuzzy control is a fuzzy control with an adaptive function that can Self-regulate the fuzzy control rules. Afterwards, we present a comparative study of those three methods. The results have shown that fuzzy control has more advantages in terms of flexibility, robustness, and ea
5、sily updated facilities with respect to the PID control of the demo model, but that PID control has much higher regulation resolution due to its integration term. The adaptive fuzzy control can dynamically adjust the rule base, therefore it is more robust and suitable to those very uncertain occasio
6、ns. Keywords: Fuzzy control； PID control； fuzzy adaptive control； nuclear reactor I INTRODUCTION Today the techniques of fuzzy logic control are very mature in most engineering areas, but not in nuclear engineering, though some research has been done (Bernard, 1988； Hah and Lee, 1994； Lin et al. 199
7、7； Matsuoka, 1990). The main reason is that it is impossible to do experiments in nuclear engineering as easily as in other industrial areas. For example, a reactor is usually not available to any individual. Even for specialists in nuclear engineering, an official licence for doing any on-line test
8、 is necessary. That is why we are still conducting projects such as fuzzy logic control application in BRl (the first nuclear reactor in Belgium) (Li and Ruan, 1997a； Ruan, 1995； Ruan and Li, 1997； 1998； Ruan and van der Wal, 1998). In the framework of this project, we find that although there are a
9、lready many fuzzy logic control applications, it is difficult to select the most sui- table for testing and comparison of our algorithms. Moreover, due to the safety regulations of the nuclear reactor, it is not realistic to perform many experiments in BRl. In this situation, we have to conduct part
10、 of the pre-processing experiments outside the reactor, e.g., com- parisons of different methods and the preliminary choices of the parameters. One solution is to make a simulation programme in a computer, but this has the disadvantage that in which, however, the real time property cannot be well re
11、flected. Therefore another solution has adopted, that is, we designed and made a water-level control system, referred to as the demo model, which is suitable for our testing and experiments. In particular, this demo model (Fig. 1) is designed to simulate the power control principle of BRl (Li et al.
12、, 1996a,b； Li and Ruan, 1997b). In this demo model, our goal was to control the water level in tower TI at a desired level by means of tuning VL (the valve for large control tower T2) and VS (the valve for small control tower T3). The pump keeps on working to supply water to T2 and T3. All taps are
13、for manual tuning at this time. VI and V2 valves are used to control the water levels in T2 and T3 respectively. For example, when the water level in T2 is lower than photoelectric switch sensor 1 then the on-off valve V, will be opened (on), and when the water level in T2 is higher than photoelectr
14、ic switch sensor 2 then the on-off valve Vl will be closed (off). The same is true of V2. Only when both VI and V2 are closed V3 will be opened, because it can decrease the pressure of the pump and thereby prolong its working life. The pressure sensor is used to detect the height of water level in T
15、I. So for TI, it is a dynamic system with two entrances and one exit for water flow. COMPARATIVE STUDY OF FUZZY CONTROL The Demo Model Structure FIGURE 1 The working principle of the demo model. BRI is a 42-year old research reactor, in which the control method is the simple on-off method. Many meth
16、ods called traditional meth- ods, when compared to fuzzy logic, are still very new to the BR1 reactor. One of these, proportional-integral-derivative (PID) control, has to be tested as well as fuzzy logic method. So far, we have tested the normal fuzzy control, traditional PID control, and an advanced fuzzy control on this demo model. To obtain a better demonstration, these three approaches have been programmed and integrated into one con- roller system based on the programmable logic controller (PLC) of the OMRON company. The purpose of tlus paper is to report comparative
