| Magnetic levitation belt conveyor is a new type of conveyor which uses magneto-electric hybrid suspension support structure instead of traditional idler support structure to realize the stable transportation of conveyor belt and its materials without contact.Magnetic levitation belt conveyor has low resistance and high efficiency.Its pioneering proposal expands the research content of traditional mine transport machinery.The nonlinear magnetic field and open-loop instability of magnetic levitation system are the main reasons leading to the unstable operation and even out of control of magnetic levitation conveyor.Magnetic levitation conveyor operating environment is complex,there are unknown external disturbances,easy to cause suspension support system chattering,instability.Based on the above problems and from the perspective of modern control theory,this paper designs the control strategy of magnetic levitation conveyor system to realize the controllable and stable operation of magnetic levitation belt conveyor.The main research contents include:(1)Based on the theory of electromagnetism and mechanical design,an electromagnetic-permanent magnet hybrid maglev model is put forward,and the electromagnetic characteristics of mixed magnetic suspension model simulation and mathematical model of dynamic analysis,in order to further explore the maglev system ability to resist disturbance,state feedback controller is designed,and lay a foundation for the improvement of sliding mode control algorithm is put forward.(2)In order to increase the robustness of the magnetic levitation control system,an improved sliding mode control method is proposed.The improved nonlinear state observer is used to estimate the state and external disturbance of the system,and is applied to the design of the sliding mode controller.The approach law of the sliding mode controller is improved to better conform to the state motion trend of the system and reduce chattering.Considering the influence of the reference trajectory on the system,the model reference trajectory is designed to make the system state more easily approximate to the set reference value.Simulation results show the effectiveness of the algorithm.(3)In view of the differential explosion problem existing in inverse sliding mode control,an improved tracking differentiator method is proposed to reduce the multi-order derivative of virtual control by obtaining differential signals through the improved tracking differentiator.The inverse hyperbolic sine function is used as the acceleration function of the differentiator and the two-phase power function is introduced to reduce the chattering and disturbance of the system.Setting rules of differentiator parameters are obtained through system sweep frequency analysis.In order to further verify the improved performance of the differentiator,the sinusoidal signal and square wave signal with noise were used as input signals to explore the influence of different input signals on the differentiator by improving the tracking differentiator,and the effectiveness of the differentiator was compared and verified.(4)For the unmodeled dynamic disturbance and external disturbance of the system,the adaptive method and RBF neural network method are respectively used to estimate the disturbance.The system is divided into several subsystems and the controller is designed by inverse sliding mode control method.To avoid the differential explosion problem,the virtual control quantity is obtained by an improved tracking differentiator.The error compensation system is designed to compensate the inconsistencies of the input signals through the improved differentiator,and further reduce the system error.Simulation results show the effectiveness of the control strategy.Figure 74 table 7 reference 119... |
