The Study On The Mathematicl Modelling And Control Strategies For Stranding Machine Tension System

In the material transport system, tension control plays an important role inthe production process. The good tension control can ensure the quality of theproduction and improve the product efficiency of the system. This thesis takesthe stranding machine as the research object, aiming at solving the problem thatthe material tension is difficult to obtain effective control, setting up thesystematic model and choosing the appropriate control strategies. The main workof this thesis can be summarized as follows:(1) The stranding machine tension system is analyzed in this thesis. First ofall, the control models of the tension system used in the industrial processusually are analyzed in the paper, according to the different accuracyrequirements of the tension system in the production process, different controlmodels can be adopted. Although the tension control systems have been used inmany fields, the different tension control systems have some characteristics incommon. Then, the stranding machine tension control system is introduced in thepaper. The unwinding and rewinding systems are introduced, the influences ofwheel roller diameter, moment of inertia and speed which is varied on thematerial tension are analyzed. Then the driving equipment in the strandingmachine is introduced, the original system used the DC motor as the drivingequipment, now the magnetic particle clutch and magnetic powder brake areused as the driving equipments, and their mathematical models are established;At the end of all, the tension detection device is introduced in this thesis, it’smathematical model is established and the imperfections of the tension detectiondevice are analyzed.(2) The mathematical modeling of the stranding machine tension system isbuilt up. Traditional modeling method of the tension system is based on theanalysis that using the torque balance equation to analyze the material tension forming process in the production process, while the influences of materialfactors on tension are ignored. First of all, this thesis takes the material itself asthe research object, using Hooke’s law and mass conservation law to analyze theforming process of tension, and building the dynamic mathematical model ofmaterial. Then the paper takes the roller as the research object, using the torquebalance law to analyze the forming process of tension, and building the dynamicmathematical models of the intermediate roll and the reeling wheel roller. At theend of all, according to the dynamic mathematical model of the roller and thedynamic mathematical of the material, the mathematical model of the strandingmachine tension system is built. Compared with other tension modeling method,this method is more accurate.(3) The stranding machine tension control strategy is determined. Thestranding machine tension control system is a nonlinear system which has a largetime-varying, strong coupling and multi disturbances, so how to select theeffective control strategy for the tension system to overcome the influences ofvarious interferences on the material tension, and how to make an effectivecontrol to the tension system are also important research contents of this thesis.According to the large time-varying characteristic of stranding machine tensionsystem, the deficiency of the traditional PI control system is analyzed. Thefeasibility of using feed-forward compensation control is investigated in thisthesis. Due to the time-varying characteristic and the uncertainty of the model intension system, the method, using the fuzzy PID control technology to design thetension control system, is proposed. According to the engineering experience, theappropriate fuzzy control rules and the membership functions are selected tocomplete the design of fuzzy PID controller. How to decoupling control speedand tension has always been our greatest concern, because there is a couplingbetween the wheel roller speed and the material tension in the tension system.ADRC can take model perturbation and external disturbance as the same statewhich is observed and compensated. The coupling between tension and speedcan be regarded as the model perturbation. Using the ADRC technique to designthe tension controller, the coupling between tension and speed can be solved well.And because of using cascade control design approach, the performance of thecontrol system is more accurate. (4) The verification and analysis are conducted on the Matlab platform.Considering the dynamic performances, static performances and the robustnessin different control systems, it can be seen that compared with the traditional PIcontrol system and Fuzzy-PID control system, the ADRC control system canachieve better control effect to meet the needs of industrial production.