Research About Air Leakage Detection PID Control System Based On Embedded System

As a very important quality index,Leakage detection always plays a very important role in the Quality and Safety tests in some industrial fields,such as automobile,aerospace,petroleum,chemical industry and so on.Because of the high price of the imported products,many companys have no choice but to take a less accuracy and less efficiency one,or do some tests by human watching and listening.So,it's necessary to develop our own measurement with a high accuracy and more efficiency,also a low cost,to satisfy the domestic users and fill the vacancy in the market.Considering 32bit ARM is the most widely used processor in recent years,which can support running an OS(operating system),and GUI(Graphics User Interface).So it is a good way to take the cost-effective S3C2440 as the controller of Leakage Detection Control System,and add some other supplementary peripherals,to construct the leakage testing machine.A Linux 2.6.3 kernel is required to build a software platform on which to write some related drivers,and also on which an interactive control interface(Human-Computer Interface),PID controller procedure,filter procedure,and least square procedure,have to be edited and built in by using the Qt Creator.(a powerful IDE can be used in several cross-platform).After the platform being built,two kinds of experiments have been made,and the results accords with the theoretical derivations made in the preceding chapters.It is said that compared to the limitations and shortcomings of the differential-pressure leakage detection mode,the PID control Volume Compensate eakage detection mode can always get a high precision easily,also less time.While the greatest strengths is that it used none of the parameters of the gaseous environment,so this makes tests much easier.To the Volume Compensate eakage detection mode,an effective control scheme always plays a key role and takes an important and critical part of the whole design.But in our tests,we got overshoots in every curve;maybe we have a pair of less useful PID parameters,while finding the right one is not an easy work with the help of Z-N calculating theory.On the other hand,valves wighted much,because they always make big noises when switchs on and off,and disturb the balance in the system,cause the overshoots display on the curves.So we can stake a much better control scheme,like fuzzy controller,neural network controller,adaptive neural networks controller,and so on,while rebuild the gas system and choose a more silent valve instead.