Research And Development On Test System For Solenoid Valve And Related Fluid Control Technique

Solenoid valve is an important actuator of industry control system, which is directly related to the security and reliability of the whole system. Whereas lacking of test equipment for solenoid valve with comprehensive function and advanced technology in our country, a multifunctional and intelligent testing system of solenoid valve is developed in this paper by cooperating with a leading enterprise. The developing of this test system can promote producing of the enterprise and the development of solenoid industry. Researches on the key technologies about system developing and fluid control are conducted with the combination of theoretic analysis, computer simulation and experimental study. The main research contents are as follows:1. The overall scheme was designed which was consisted of the computer test and control system and the fluid control system. For the developing the computer test and control system this thesis utilized the software and hardware sources. In hardware part the integrated controlling scheme about IPC and PLC was researched with great emphasis on, and the anti-interference technique was discussed. In software part with the idea based on virtual instrument technology the test platform for all performance tests of solenoid valves was designed and the test software was developed with Labview. The software could fulfill automatically the performance tests for solenoid valves, and possesses the function of data collection, controlling, analyzing, result management and printing, as well as intuitionist user interface.2. For the solenoid valve test-bed has the characteristic of being used frequently and acting intermittently, liquid in pipeline is always in the state of unsteady flow and it makes the pipeline vibrating which would damaged the delicate sensors and fluid components. So the dynamic characteristic of main test pipeline in solenoid valve test-bed was studied, and the impedance was applied to research the conduction of resonance and the characteristic of pressure dissemination in frequency domain. Furthermore, the simulation research was carried on with approximation method about frequency domain characteristic for pipeline. From the results of simulation we made the reasonable structure design about the diameter and length of the pipeline.3. In this thesis mechanism of inducing hydraulic impact and pressure fluctuation were analyzed, and the maximum value of impact pressure and the fluctuation frequency of pump were calculated. At the same time it is difficult to remove the impact and fluctuation essentially, but to adjust the impedance, for example changing the length of pipeline or the structure of components, etc, is constricted by the reasonable system design including the normal running state of system and special location of components. Consequently, accumulators were installed to attenuate or absorb impact and fluctuation. Furthermore, its related parameters were chosen rationally to achieve the best effect of eliminating vibration based on the research on the working principle and dynamic characteristic of accumulators.4. Pressure control scheme for solenoid test-bed was designed. In view of the problem about pressure precisely control the pressure control principle was analyzed, and relative components are introduced. A mathematical model of system pressure is created, and the intelligent algorithms which are fuzzy adaptive PID control were proposed by combining advantages of fuzzy control and PID control as the best control strategy for system pressure control. The pressure simulation experiments were carried out in leakage and sealing experiments.5. Based on the analysis of the key problems of fluid control, the test-bed for solenoid valve was designed of which structure and principle were explained, and built it in the workshop. Furthermore, according the principle of the performance tests analyzed above, test methods were conducted on different types of solenoid valve products about delivery inspection and type tests followed the national standards and industry standards. At last the test system for solenoid valve which was designed and developed was operated actually, and solenoid valves were tested in all performance tests. The tests prove that the feasibility of the method about the design for solenoid valve test-bed and researches on fluid control technique in this thesis, and also prove that not only fully meet the needs of actual batch production, but also have a perfect function and high automation in wide applications.The related research results not only provide theoretical foundation and technical support for successful development of a high performance solenoid valve test system, but also have some value in academic reference for theoretical research and practical applications in the automated measurement and control fields.