Research On Sliding Mode Control Of Horizontal Vibration Prediction Of High-speed Elevator Car System

In recent years,the high-rise development of urban buildings makes the popularization of high-speed elevator become an inevitable trend.The high speed of the elevator makes the horizontal vibration of the car system more intense.Strong vibration not only affects the comfort of passengers,but also affects the normal use of various parts of the car system,and even leads to safety accidents.At present,there are passive and active control methods for elevator horizontal vibration reduction.Due to the wide application range and good flexibility of active control,it has become the main effective method to solve the horizontal vibration of high-speed elevator car system.Therefore,to explore the horizontal vibration mechanism of high-speed elevator in the real working environment,and to further study the active vibration reduction control strategy,has important theoretical research significance and engineering application value to realize the safe and comfortable operation of high-speed elevator.Firstly,the complex high-speed elevator car system is reasonably simplified.Considering the nonlinear characteristics of the spring and damping in the guide shoe and the unevenness excitation of the guide rail,the nonlinear model of the guide shoe and the excitation model of the guide rail are constructed.According to Newton's law of motion,the nonlinear horizontal vibration dynamic model of the four degree of freedom car system is established.The real elevator experiment is carried out in the 7m/ s high-speed elevator test tower of the cooperative company.The actual vibration acceleration curve of the elevator is measured by the elevator vibration acceleration dt-4a,and compared with the simulation results under the MATLAB / Simulink software environment.The results show that the established dynamic model is close to the actual elevator model,It provides a model basis for further exploring the active vibration reduction strategy of high-speed elevator.Based on the above model,the horizontal vibration state equation of high-speed elevator car is established by taking the guide rail displacement as the main excitation.The system state is expanded by Taylor expansion and ended appropriately to obtain the required continuous prediction model.The obtained prediction model and system control quantity are introduced into the quadratic performance index of predictive control.The nonlinear continuous predictive active control law is solved by optimizing performance index,and then the controller is designed.Finally,MATLAB / Simulink is used to simulate the nonlinear continuous predictive control strategy.The results show that the average value,maximum value and root mean square value of the horizontal vibration acceleration and displacement of the car system are reduced by more than 29%,which proves the effectiveness of the nonlinear continuous predictive control strategy.It provides some theoretical and methodological guidance for the active vibration control of high-speed elevator.Considering the uncertainty of elevator parameters and the influence of external air flow disturbance on the horizontal vibration of the car system,the uncertain nonlinear car system model is established.A predictive sliding mode controller based on adaptive fuzzy is designed to reduce the horizontal vibration of car system.The integral sliding mode surface is introduced into the quadratic performance index of predictive control,and the optimal predictive sliding mode control law is obtained.At the same time,in order to reduce the influence of the complex uncertainty of the car system,a fuzzy logic system is established to approximate the complex uncertainty online,and the continuous smooth hyperbolic tangent function is introduced into the sliding mode switching term to compensate the fuzzy approximation error.Finally,the horizontal vibration acceleration and displacement of the car system under different guide excitation forms are simulated and analyzed,which verifies that the proposed controller can effectively suppress the horizontal vibration of the elevator,and ensure the stability of the elevator at high speed and the comfort of passengers.Aiming at the problem of actuator input saturation in the actual operation of highspeed elevator,combined with the approximation characteristics of RBF neural network,the good compensation of input limited part is realized.At the same time,in order to further improve the robustness of the system,a robust compensation controller is added to prove the stability of the system in the presence of input limited.Finally,MATLAB/ Simulink is used to compare the compensation and no compensation.The experimental results show that the designed controller can deal with the problem of input limitation better,exit saturation faster,and improve the performance of the controller.It provides a new method for active vibration reduction of uncertain nonlinear high-speed elevator car system with input limitation.