Study On The Real-time Measurement And Control System For Static Hydraulic Universal Testing Machine

Testing machine is used for carrying on the material mechanics performances, the mechanical indexes got at last. All kinds of the inspections of products quality, the scientific research of materials and the teaching tests need use testing machine. The common experiment for draw, compress, crookedness, and shear is carried on the static universal testing machine. Of our country the static universal testing is numerous and spreads all over the place. The majority don't possess automatic measuring ability, Run by way of adjusting the oil valve manually. The test means is behindhand, the amount of labors is heavy and the test result is inaccurate etc. If carried on proper technological transformation to its instruction system, recorder and control system, it will raise its technical feature and use greatly, Serve experiment and teaching better.This system applied advanced virtual instrument technology, sensing technology, testing technology and control technology to the static testing machine, come to realize the automatic measuring of the performance parameter of mechanics. Among them the test data's gathering in real tune, the data's automatic processing analysis and the loading velocity in testing is the focal points of system research.On the basis of fully grasp a large amount of information of testing machine, the systemic hardware was put up and the software was designed for the digital static universal testing machine with virtual instrument technology. The text analyzed the operation principles of the systematic hardware's different components. The digital system utilized pressure sensor, extensometer (have another name: strain gauge) and the displacement sensor measure every test data, adopted FIFO buffer memory technology and realized the gathering in real time automatically of the test data; The system also utilized the memory function, the logic analysis and the fast calculation, have realized the automatic processing of the test data, controlled the flux and the oil pressure with the electrohydraulic proportion valve to realize the running of the testing machine automatically. Supported by the developing platform of virtual instrument LabWindows/CVI's strong function on the software, the system adopted the method of module design and realized the signal measuring, the dynamic curve showing and the test data analysis correctly. Also the system utilized the multithreading-measure technology, integrated the Adaline self-adapt unit into the simple and practical PID control, realized the accurate output of the signal and achieved the control of stress, distortion and fixed-point stress.The whole system has the full function and the friendly interface to operate conveniently. The result indicated that the numerical system of static hydraulic universal testing machine based on virtual instrument had increased stability of experiment and dependability of operating, avoided the artificial reading-error and the deviation of the result of the tests, improved the precision of testing and test efficiency. This system can be applied to steel, building materials, metallurgy, chemical industry of our country extensively, have the high value of popularization.