Controlling System Of Injection Modeling Machine On Fuzzy-control

Plastics are a new material, which is developed just from 20 century. Now, thevolume output of plastics on world has caught up with and has exceeded steel,becoming a big kind of material which human are using. The plastic industry of ourcountry is developing fast and the application of plastic product has gone to everydepartment of national economy further.The important role of plastic product in national economy and daily life makesthe quality of plastic product, which people need, more and more higher. Theproduction efficiency and the quality of plastic product affect the development ofnational economy directly. Therefore, how to produce flawless plastic product isthe problem that plastic production enterprise most cares for.The factors that affect plastic product quality is many and complex, but sumup, that some aspects: polytechnic condition, polymer material, shrinkage rate andits fluctuation, mould's structure and precision, and so on. So injection-modelingmachine is a complex big system, which has such features: many variety,distribution parameter, discrete, intermittence work, stagnant, nonlinear, strongcouple, and it need person to participate in. It is nearly impossible to describeproblems in system with traditional quantitative model, and it is very difficult evenimpossible to establish its accurate mathematics model. So, under the condition ofpolymer material, mould, machine given, the most key problem of processingflawless product is how to determine the initial parameter. But these parameters,which affect product quality and property index, are often mutual restrict evencontradict, therefore the machine rely on wisdom and the experience of humanexpert greatly. Older practice is to find out a initial point (is also a group ofinitialization parameter) first, then from this initial point, decide the modificationintensity and direction of parameter, according to current defects and currentparameters. Such procure have great blindness, especially when some kinds ofdefects at the same time appear, and the parameters that affect these defects arealso conflicting. This case is very hard to handle. Therefore traditional method of "try " is not only time-wasting, material wasting, but also is disadvantage in defecteliminate.Fuzzy-control technology is a kind of new control technology that developingin recent years. It is used to solve those complex systems that are hard to solve withtraditional method mainly, and its purpose is to raise systematic robustness, faulttolerance and to solve the control system problems t-hat are serious nonlinear andindeterminate. Fuzzy-control is different from traditional control. It does not relyon the mathematics model of controlled object, and is a kind of means to realizeautomatic control based on the operation of summary experience. It forms controldecision table according to artificial control regular, then the size of control isdepending on the table. This kind of control method is simple and practical, andhas accords with the logic thought of people. Now it has gotten very goodapplication in industrial scene.Fuzzy logic is good at simulating human thought and inference pattern. Thisfeature is very suit for injection-modeling machine controlling system, whichcannot establish the accurately mathematics model.The paper designed a set of Injection Modeling Machine control system basedon fuzzy logic. In Chapter 3 the paper study the control method of fuzzy logic:First, it represents the working principle of Fuzzy-Control system. It is shown asThe basic principle of Fuzzy-Control is shown as Fig.1. Its key part is fuzzycontroller. The control law of fuzzy controller is realized through the program ofcomputer. The course that realizes the fuzzy control algorithm of one step describesto be as follows: computer gets the accurate value of controlled parameter bysampling, then the value will be compared with the given value to get the errorsignal E. Usually, the E would be one of fuzzy controller inputs. The accurate valueof E would be converted to fuzzy value. The fuzzy value of signal E can beexpressed with corresponding fuzzy statement, then we can get a subclass "e"("e"is a fuzzy vector).In Fuzzy-Control system, output value and the input value of controller are thedistinct quantity that has definite value. But when carrying out fuzzy control, fuzzyinference course is carried out through fuzzy language variable, and it has certaincorresponding relation between distinct quantity and fuzzy quantity. By fuzzyinterface the accurate value xi can be converted to the fuzzy quantity E that fuzzycontroller can distinguish. Via fuzzy inference this fuzzy quantity E could find thecontrol rule that matches in knowledge storehouse. The rule U is also a vaguequantity, and only when it is had been converted to corresponding accurate value yiit can be output to actuator.In chapter 4, I designed Fuzzy-Control system aim at the feature of InjectionModeling Machine. First, before trying to produce a product, we must determine agroup of initial parameter. Then, from this starting point we need to modify theparameter according to the defects that product has continuously until produce theacceptable flawless product.In the course of actual production, the norm that parameter option is raisingproduction efficiency or guarantee machine safety, therefore initializationparameter option determines according to the information that material supplierand machine manufacturer offer, so this can often cause the plenty of appearancesof product defect.A good initial point will establish good foundation for later course. Newresearch shows: only when the material's surfacing velocity is stable during theinjecting stage, that the machine could produce qualified product. Throughcontrasting and measuring the pressures of fuse-element on the place of spraynozzle, under different course parameter we confirm that the mould cavity...