Research On Optimal Terminal Sliding Mode Control Of Horizontal Vibration Of High Speed Elevator Car System

Urbanization continues to accelerate,urban population density is getting bigger and bigger,and the increasing demand for housing and the increasingly scarce land resources force the buildings to expand in the orientation of high-rise,which makes the operation speed of elevators rise continuously.Elevators are growing rapidly in the direction of high speed,and their vibration problems are becoming more and more intense.In turn,passengers riding the elevator will experience dizziness and vomiting,breathing faster,and other adverse reactions,even beyond the human body’s tolerance.In addition,the violent vibration of the car will aggravate the damage of elevator instruments and meters,cause elevator failure,lead to more serious elevator safety accidents,and lower quality of elevator operation.Therefore,to enhance the comfort and safety of elevators,the design of targeted active vibration reduction strategies to effectively suppress horizontal vibration during the operation of elevators is one of the critical problems to be solved for high-speed elevators.(1)A reasonable model simplification was conducted considering the structural composition and vibration characteristics of high-speed elevator guidance and car systems.Based on the theory of rigid body dynamics,a 4-degree-of-freedom active control model with the symmetric distribution of the controller center and a typical excitation model with uneven guide rails were established.The horizontal vibration acceleration response of the actual ladder is obtained using the DT-4A acceleration test apparatus in the 120-meter-high elevator experimental tower of the partner company.Using MATLAB numerical simulation software,get the simulation of acceleration response of the system under the same working conditions.Compare simulated and measured values to verify the accuracy of the constructed 4-degree-offreedom high-speed elevator model.(2)Considering the hysteresis of the car system and the input delay of the controller,the Hankel Toeplitz model of the car system is derived based on the excitation hysteresis response.Combined with the actual measurement data of the real elevator,the least squares method is used to identify the parameters of the car system model.The horizontal vibration model of the car under the real vibration response is obtained.Design a sliding mode control strategy to attenuate the horizontal vibration of the lift car system.The rail excitation was used as the input to the car system,and the MATLAB software was applied to perform simulation experiments.Verified the effectiveness of the proposed control strategy for active vibration reduction.(3)An optimal terminal sliding mode control strategy is designed to actively suppress the horizontal vibration problem caused by the guide shoe nonlinearity and external disturbance uncertainties.A non-singular terminal sliding mode surface is defined,a fast convergence law containing terminal attractors is introduced,and a non-singular terminal sliding mode controller is established.A random weight particle swarm algorithm is used to optimize the parameters of the terminal sliding mode controller,which can improve the convergence speed and accuracy of the system and improve the vibration suppression performance and robustness of the terminal sliding mode controller at the same time fast optimization search.The numerical simulation of the lift car system is carried out under light load and heavy load conditions by using low radiation and high frequency Gaussian white noise excitation signals and occasional strong amplitude pulse excitation signals.The proposed control strategy is able to significantly attenuate the vibration index values of the system,demonstrating the ability and robustness of the optimal terminal sliding mode strategy to suppress vibrations.