The Design And Implementation On Data Collection And Control System Of The Hydraulic Universal Material Testing Machine

Material testing machine is a precise testing device which plays a very important role in the fast development of the material science. There are many old-fashioned material testing machines in factories and schools. They can not satisfy the requirements of real-time testing and automated testing, and they also have poor expandability, reliability and control precision. For the WE-type hydraulic universal testing machine, an approach is proposed in this thesis to solve the above problems. The idea of this approach is to improve the machine by using the modern computer testing technology. This approach effectively improves the measure and control precision of the material testing machine, realizes auto testing and data processing, decreases the human influence in the testing and experiments.The control system for the hydraulic universal testing machine is a two-level system, that is, it consists of the upper computer and the lower computer. The upper computer, which is a PC, is responsible for issuing the control command, receiving data and management of the system. The lower computer, which is an AVR single chip microcomputer, is responsible for the execution of the control and test commands. The upper computer and the lower computer communicate by the serial communication.According to the idea of modularized programming, the software of the upper computer consists of the function modules of sending and receiving data, display and print, data storage, the control of the lower computer, etc. The software of the upper computer is developed by Delphi. The standard drawing component is used to display graphically the data received from the lower computer. The standard database component in Delphi is used to access database. Since the acquired data are stored in database in time, the system can provide them to the scientific experiments.The lower computer consists of the AVR single chip microcomputer, the stress sensors, the movement sensors, the extensometers, the oil pump electric motor, the control circuit for keyboard, the circuit liquid crystal display, etc. The software of the lower computer mainly consists of the initialization module, the main program module, the serial communication module, the data acquisition module, the digital displaying module, the keyboard module and the control command output module. The software of the lower computer is developed by the AVR studio, an integrated development environment. Using the Proteus software, simulated experiments are conducted for the hardware system of the lower computer, obtaining good experiment results.Communicated by serial communication, the upper computer and the lower computer jointly control and manage the system. This approach realizes the dispersion of the control procedure, improving the reliability of the system. Since the management, operation and display are realized in the upper computer, the system has good usability. The implementation of the control system for the hydraulic universal testing machine improves and re-uses the old machine. The system results in good social and economic benefits, since not only it satisfies the requirements of the modern teaching and scientific research, but also it saves much money for our country.