Study On The Pressure Control Method Of Large Scale Building Curtain Wall Test System

According to the developing of architecture technology and the limitation of space in modern city, more and more skyscrapers are being built all over the world. In order to decrease the building weight and for the decorative purpose, a large quantity of building curtain walls are being used in skyscrapers. So the whole society is paying more and more attention to the quality test of skyscraper's large building curtain wall.The national building curtain wall test standard includes three main parts: 1) Wind Resistance Performance Test; 2) Air Permeability Performance Test; 3) Water Tightness Performance Test. And the automatic pressure control is the base and key point of large building curtain wall test.The basic processes of building curtain wall test are: Firstly, the building curtain wall should be installed on one side of the rectangular space of the test system, constructing a relative sealed space with other 5 walls. And then, blow in (negative pressure) or draw out (positive pressure) the air, in order to make the pressure variety accord with the request of national building curtain wall test standard. Finally, decide whether the example building curtain wall is safe or not.There are several practical problems should be solved before carrying out the automatic pressure control system:1) The difference between positive and negative pressure control.2) This system has several inputs (one electromotor, four pneumatic valves and one leakage valves) and single output.3) The size, installing way and material of building curtain wall are different for each time.4) There are lots of air pipes in this system, and the path is undetermined for each time.5) The communication between sampling equipments, executing equipments and control system is quite complex. Special software should be designed and developed to process the signal data and finish automatic pressure control.So, it's a nonlinear, undetermined and complex control system. Because of simple method, good robustness and high reliability, PID control theory has been used in industry process control widely. Base on practical condition, we chose PID control theory as the final control method, and realized the automatic pressure control system as the following steps:1) Constructing a manual building curtain wall test system and acquiring the basic testing data to find pressure control rules. The difference between negative and positive pressure control and the influence of size, installing way and material for automatic pressure control system.2) Analyzing the testing data to find the math relation between inputs and output.3) Using PID control theory to instead of manual pressure control.4) Developing the software to process signal data and realize PID control theory by Labview.5) Doing test of automatic pressure control on the real building curtain wall system for parameter adjusting and selecting.The paper introduces each main function modules of large building curtain wall test system, and presents how to contribute math relation between several inputs and single output. Finally, describe how to realize PID control theory in this system to finish the data processing and automatic controlling, by Labview.Above all, the emphases and innovations of this paper are: 1) Contribute building curtain wall test system. 2) Find the math relation between inputs and output. 3) Finish the automatic pressure control by PID theory. 4) Develop the software by Labview. 5) Communication between sampling equipments and data process.