Research On Conveyor Belt Tension Control System

Belt conveyor is an important equipment for material transportation.It is widely used in coal,metallurgy,mines and ports,and it is developing towards large capacity and long distance.In the process of starting and braking,long-distance conveyor belts will store or release a large amount of energy,resulting in significant stress fluctuations,and unstable operation of the conveyor.The tensioning system is an important part of the belt conveyor.The tension force provided by the tensioning system affects the tension of the conveyor belt.If the tensioning force provided by the tensioning system is not controlled effectively,the belt will be slippery,stagnated,and severe problems such as fracture.Therefore,the tensioning system plays an important role in ensuring the safe and reliable operation of the conveyor.In order to solve the shortage of tensioning force,slow response and inability to automatically adjust the tensioning force of the existing tensioning system,this dissertation studies an electro-hydraulic servo tensioning device and proposes the application of a dynamic matrix control algorithm to design the tensioning device's control.The system provides constant tension for the stable operation of the belt conveyor,which is important theoretical and practical significance.First of all,in order to solve the problem that the existing hydraulic tensioning device can not achieve the continuous adjustment of tension and the problem that the system pressure cannot be maintained within a fixed range,this dissertation designs a hydraulic tensioning device that can adjust the tension in real time with using servo proportional technology.The tensioning device utilizes an accumulator to keep the system pressure within a fixed range and installs a one-way valve in the two chambers of the hydraulic cylinder to prevent the sudden tension from excessively damaging the hydraulic components and the designed hydraulic tensioner.In order to perform stability analysis,an accurate mathematical model was established.Then,the studied tensioning device was applied to the belt conveyor simulation model,and a simulation model of different tensioning modes was established by using AMESim software.The tension mode,load characteristics,and braking,which affect the dynamic characteristics of the conveyor belt,were simulated and analyzed.By analyzing the tension force provided by the tensioning device and the tension response curve of the maximum tension point of the conveyor belt,the starting and braking modes of the conveyor were optimized.The simulation results show that the automatic hydraulic tensioning method,two sinusoidal start-ups and controlled shutdown can effectively reduce the tension peak value.Finally,for the nonlinear,large-inertia,hysteresis,and time-varying characteristics of the conveyor belt,traditional PID control algorithms is difficult to control effectively.This dissertation proposes a DMC-PID cascade control strategy that combines Dynamic Matrix Control(DMC)and PID control.The corresponding control model was established by Simulink and the tension response curve of the tensioner was compared under different control algorithms.Simulation results show that the DMC-PID cascade control can improve the response speed of the tensioner and enhance the system robustness.The electro-hydraulic servo proportional tension device and DMC-PID cascade control strategy designed in this dissertation effectively reduce the peak value of the braking tension of the conveyor belt,increase the response speed of the tensioning device,and improve the robustness of the tension control system..