Design Of Temperature And Humidity Digital Control System Of Temperature-Stress Testing Machine

With the rapid development of high-strength concrete,the existing temperature and humidity control system of temperature-stress testing machine cannot meet the requirements of evaluation test of high-strength concrete crack resistance.Therefore,the existing temperature and humidity control system is optimized in this thesis,and the design of the temperature and humidity digital control system is completed,with the support of 2015 special innovation of Hubei Province.This optimized temperature and humidity control system can achieve accurate measurement and control of temperature and humidity,as well as weak coupling of adjustment.The temperature and humidity digital control system can improve the accuracy and reliability of evaluation test of high-strength concrete crack resistance.The main work accomplished and the results in this study are as follows:(1)The hardware of temperature and humidity digital control system of temperature-stress testing machine is designed.Firstly,the design requirements of temperature and humidity digital control system are put forward.Secondly,the hardware structure of the system is designed according to the design requirements.Thirdly,the hardware circuit is designed,including hardware selection,the main circuit and operating circuit,PLC switch I/O circuit,pulse trigger circuit,PLC communication interface.(2)The research on fuzzy decoupling control strategy of temperature and humidity is completed.Firstly,the principle of fuzzy decoupling control of temperature and humidity is analyzed.Secondly,the temperature and humidity fuzzy decoupling controller is designed for the coupling characteristics of heating circuit and humidification circuit.Thirdly,the simulation results show that the temperature and humidity fuzzy decoupling control strategy has the advantages of short steady-state time,weak coupling and strong robustness.(3)The software of temperature and humidity digital control system of temperature-stress testing machine is designed.Firstly,the PLC control program is designed,including the main program,initialization program,temperature and humidity data collection program,temperature and humidity fuzzy control program,PLC and inverter communication program.Secondly,the monitoring interface is designed,including the welcome interface,the main interface,real-time monitoring interface,parameter setting interface,fault alarm interface.(4)The experimental study on the temperature and humidity digital control system of temperature-stress testing machine is completed.Firstly,the test platform is set up.Secondly,the trial production of the temperature and humidity digital control system is completed and the unit is debugged.Thirdly,the system test is conducted and the test results are analyzed.The results of this study can not only improve the accuracy and reliability of high strength concrete crack test,but also lay a good foundation for the theoretical research on the crack resistance of concrete.