The Measurement System Of Pneumatic Cylinder Comprehensive Properties

The Pneumatic Cylinder is widely used in many Automation fileds, depended on its advantages of quick speed, simple structure and low cost. Now it is used in mechanical manufacture, metallurgy, petrochemical engineering, textile industry, electronics industry and so on. Its working substance is compressed air, and it carries out the predictive operation. Since the Pneumatic Cylinder is widely used, its performance is very important. If we know its performance before we use the cylinder, we can use it more correct and effectively. The research subject is to set up a test system which can test most properties of the cylinder, and judge the cylinder can be used or not.The whole thesis consists of four sections:Chapter one first briefly introduced the pneumatics technique feature, the current application situation and the frontiers of pneumatic control techniques. Then it representd the importance of the research subject. The methods to test the performance of the cylinder are also described in the chapter one. The last the section points out the main research work of the subject.Chapter two introduced the phenomenon of creep and detailed describe the mechanism of cylinder crawling. The derivation of the minimum speed at which the crawl will not happened and the influencing factor are also inculded. Then the chapter describe the leakage of the cylinder, the physical model of leakage is introduced in the end of the chapter.In the chapter three, a testing system was developed for investigating the performance of the cyclinder, the system is consist of the hardware and software parts. The hardware parts include driving system, sensors, data acquisition card and the connecting parts. The software part is mainly consisted of AID and D/A channels for the data in and out. To compile the software, the C++ language and the Visual C++ are used. To control the speed and the turning of the driving, we use the software supplied by Festo company.Chapter four represents the methods of how to process the acquired data. The methods for processing the crawl data is polynomial fitting ; to analyse the leakage rate, we can analyse the acquired data ,then compare with the theoretical leakage,we could judge wether the cyclinder is normal or not.By processing the displacement data, we can know the cyclinder speed.