Research On Control Technology Of Conveyor Tension System Based On Viscoelastic Belt Model

As one of the most important transportation equipment for bulk materials,the belt conveyor is widely used in various major transportation operations.With conveyors becoming larger and faster,researchers have been paying close attention to their dynamics and control issues.The belts generate large longitudinal vibration under the influence of excitation,which are often accompanied by sharp tension changes and great energy fluctuations.The automatic tensioning device is an important part to ensure the normal startup of the conveyor.But the tension provided by the tensioning system maybe insufficient and its response speed is slow,which causes the local tension to be too large or too small,leading to major safety accidents in serious cases.In the view of the problems existing in the operation of the belt conveyor,this dissertation conducted in-depth research,mainly including:(1)Starting from analyzing the startup of the belt conveyor,this dissertation determined the starting curve parameters.This dissertation established a discrete model of the conveyor belt with kelvin-Voigt as the basic unit in AMESim.Then five commonly used acceleration curves were set for simulation analysis when the conveyor was started.The simulation results showed that the S-type acceleration curve had a small tension fluctuation range,small speed error and high precision.When the start time was determined to be 120 s,the dynamic performance of the conveyor belt was better.(2)This dissertation proposed an adaptive control method based on the Lyapunov stability theory.This dissertation established the nonlinear model of the servo valve and the state equation of the electro-hydraulic servo tensioning system in Simulink.Then the servo force tracking control equation was derived,and the final simulation results showed that the proposed control method could track the force signal better.There is no large overshoot and oscillation.The system had a fast response speed,and can meet the belt tensioning requirements.(3)This dissertation proposed that the tensioning system adopted the threepoint,head,middle and tail,tensioning method.AMESim and Simulink were jointly simulated and the control methods of three tension points were set respectively.The simulation results showed that the tension fluctuation value was significantly reduced with multi-point tensioning.The damage of the conveyor belt by cyclic stress was reduced,and the tension curve was more stable,achieving the expected control effect.