| Magnetic levitation,as a technical way to make objects have no surface contact through magnetic interaction,has the advantages of environmental protection,quietness,and long service life.Therefore,after the train is suspended by the magnetic levitation technology,it can obtain a higher speed and a more comfortable riding experience.When controlling a maglev train,a variety of external disturbances will reduce the real-time control performance of the train,such as:the air gap change of the carriage rail,the unstable power supply current,the qualitative magnetic field disturbance,etc.,in order to improve the dynamic response control ability of the train,it is necessary to control the The system carries out targeted improvement and optimization.The thesis takes the control system of the maglev train as the research background,through the mechanical decoupling of the maglev train,the overall control of the maglev train is simplified to the control of a single-iron levitation system.Magnetic levitation is a nonlinear time-varying system,and the traditional PID control method cannot effectively suppress the unconventional disturbance,instant parameter variability,feedback deviation correction degree,etc.generated during the operation process.Therefore,the thesis adopts a double closed-loop control structure to enhance the system’s adaptability to parameter changes,designs an outer-loop controller based on trapezoidal integral fuzzy PID control algorithm to solve the problem of poor control performance in nonlinear time-varying systems,and builds an experimental platform for simulation and test.The main content and work of the thesis are as follows:(1)Analyze the working principle of single ferromagnetic levitation and combine the basic characteristics of the single ferromagnetic levitation control system to complete the establishment of the physical structure of the controlled object and the establishment of the mathematical model.According to the conventional design of the current maglev control system,a double closed-loop control structure consisting of an outer loop position loop and an inner loop current loop is formed.(2)Because the suspension system has the characteristics of fast response,the traditional PI current loop controller is designed;in order to improve the control accuracy of the outer loop,the module PID control algorithm based on trapezoidal integral is designed.A double closedloop simulation control structure was built,and compared with traditional PID control and fuzzy PID control respectively,it verified that the control algorithm designed in the thesis has strong followability and robustness.(3)The hardware design of the experimental platform includes mechanical structure and control circuit design.The mechanical structure design enables the electromagnet to move with a single degree of freedom;the circuit design part completes the design of the minimum system of the TMS320F28335 control chip,the power supply of the electromagnet,the state acquisition circuit,the control logic and the communication module.(4)Complete the software design of the experimental platform in combination with the hardware design structure,and realize the control chip to mobilize the hardware modules,such as the control logic of the main program and the data acquisition process of the sampling control subroutine.Write the relevant module code and give the program flow chart.An experimental platform is set up for system testing.Through the system’s related experiments of changing the size of the air gap to control the stable suspension of the electromagnet,the feasibility and adaptability of the controller in the thesis are verified.Comprehensive experiments show that the trapezoidal integral fuzzy PID control algorithm is superior to the electromagnet,which makes the single ferromagnetic levitation control system meet the design requirements,and provides a new idea for the development of magnetic levitation control technology. |
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