| Incoherent Broadband Cavity Enhanced Absorption Spectroscopy(IBBCEAS)technology,as an emerging air pollution measurement technology that has rapidly developed in recent years,has many unique advantages in monitoring air pollution.Throughout the measurement process,such as calibration of mirror reflectivity for high reflection mirrors,protection of purge gas paths,correction of effective cavity length Multiple experimental processes,such as the measurement of trace gases,require high gas flow control accuracy and performance requirements.Unstable gas flow rates can lead to significant deviations and distortions in experimental measurement results.Moreover,the traditional gas flow control devices on IBBCEAS experimental platforms both domestically and internationally are mainly commercial products,with defects such as large volume,heavy weight,and high cost of control equipment,There are also many disadvantages to the conduct of the experiment.Based on this,this article designs a gas flow control module with small volume,light weight,low cost,excellent control accuracy,good responsiveness,and strong robustness based on the actual needs of the IBBCEAS experimental platform.On the basis of traditional control theory,this article combines PID control technology with fuzzy control technology,and uses adaptive fuzzy PID as the core control algorithm of the entire flow control module.A suitable gas flow adaptive fuzzy PID gas flow controller is designed for the control module.Through simulation and comparison,it is confirmed that it has better performance compared to traditional control methods.In terms of the implementation of control algorithms,hardware and software have been designed separately.In terms of hardware,a gas flow sensor based on thermal principle and MENS technology was selected as the detection mechanism,an electric control valve was selected as the executing mechanism of the module,and STM32F103 was used as the core controller of the entire control module.The power supply circuit,minimum system circuit of the control unit,sensor signal conditioning circuit,and automatic control valve drive circuit were designed respectively.In terms of software,this article mainly uses C language as the programming language.By using the UCOSⅢ real-time operating system in the underlying hardware,the real-time requirements of the module are maximized.In the writing of the underlying driver,the A/D acquisition function,D/A output function,and the adaptive fuzzy PID algorithm are completed.Furthermore,the master-slave communication scheme is designed and appropriate communication protocols are selected,And according to the experimental requirements,the upper computer was written using Labview.Finally,experimental testing and analysis were conducted on the designed gas flow control module.The experimental results show that the gas flow control error of the module is small,and it is less affected by external environmental factors.The control effect is good,and the robustness is strong.And it was used in actual IBBCEAS experiments to achieve various required functions in the experimental platform.Atmospheric NO2 detection and a series of supporting experiments were carried out,and compared with the original experimental equipment.The experimental detection results were good,confirming the accuracy and reliability of the control effect of the gas flow control module involved in this article,meeting the overall requirements of the experimental platform and replacing the original control scheme,The expected design goals have been achieved.Figure 71 Table 10 Reference 83... |
PDF Full Text Request