Research And Development On Computer Aided Test System For Hydraulic Experimental Bench

The hydraulic computer aided test(CAT) is a newly arising comprehensive academics. The scope involves hydraulic, automatic control, microcomputer, test techniche, dependability and so on. Hydraulic CAT makes use of computer to build up a data acquisition and numerical control system, and connects to experimental bench. The computer is in charge of data collecting, quantifying, processing and outputing the test result as concern as each experiment parameter such as pressure, tempreture, flow, rotational speed and torque. In the process of experiment, the computer can control the test process according to the numerical feedback and request of artificial input to achieve the object of closely tracking and controlling the state of expriment bench and test piecese. Thus complete the test on the performance of hydraulic products at high speed and high precision.In order to make the experimental teaching of Hydraulic Transimission adapt to the developmental request of testing and controlling technique and cultivate students both having firm theories base and familiar with advanced testing and controlling technique. Adopting modern transducer and relying on visual software operating platform, upgrade the experiment equipment and make it become a simple operation, intuitionistic experimental progress, higher test precision, and economic, intelligent, multifunctional experimental bench. In this case, on the one hand it can exert the former experiment bench's function fully; on the other hand it enriches the contents of practice teaching and integrates the hydraulics, electronics and mechanics. Thus exploiting a new method and a path for the computer aided test technique in the application of experimental teaching.According to the above-mentioned circumstance, this paper discussed the research and development of hydraulic experimental bench computer aided test system. Bring the advanced computer technology into hydraulic experimental system and make the integration of mechanics, electronics and hydraulics come true. The performance of gear-type pump and dynamic characteristics of overflow valve is the two main testing experiment of hydraulic experimental bench. The parameters that need to be tested mainly include pressure, flow, rotational speed and torque. According to these parameters, acquire the experimental curve of the gear-type pump's performance and overflow valve's dynamic characteristics and achieve the object of validating and evaluating their performance. On these ground we built the platforms of hardware system and software system to carry out this target.In the hardware system, what is to face first is the choose of transducer and data acquisition card, and then the principles and methods of data acquisition to each signal are what we have to concern about. Disposing is needed after the signals are collected to satisfy the request of data acquisition card. For the test system, the experimental data is subject to suffering various of interference in the process of acquisition and transmitting. This will influence the accuracy and dependability of data analysis inevitably; hence we analyzed the interference's mechanism of production and gave some anti-interference measures. In the software system, analyzed the choice of the software develop platform first, then analyzed the implement of bottom input and output ports'data operate in the environment of windows operating system. There are many functions the software system has to carry out including data acquisition, data analysis and disposal, display, data storage and print and so on. According to these functions, we divided the software system into data acquisition module, data disposal module, man-machine interactive interface, data storage and print module. Because this system is a continuous work, and needs to carry out several missions in the meantime, such as in the process data acquisition, the actions of display, data processing and data storage are running simultaneously and the inputs of mouse and keyboard have to be accepted at the same time. This relates to multi-task program. Dividing functional modules into several treads and using the multi-treads technology implement data's acquisition, analysis and process. We make the serial communication come true between Industrial Personal Computer and Program Controller by using control piece of Visual Basic 6.0.The experiments of gear-type pump's performance and overflow valve's characteristic on the spot showed that the developed hydraulic experimental computer aided test system can meet the need with experimental teaching and proved that idea and method are feasible in the design of hydraulic experimental computer aided test system. This system improved automatic and intelligent level. It renovated experimental contents and experiment methods, and provided some feasible ways and references for the experimental equipments'updating and rebuilding.