The Research Of Tension Control Based On Rotary Magnetorheological Fluid Damper

As a new type of controllable smart material, Magnetorheological Fluid (MRF) exhibits well MR effect in presence of magnetic field. Some clutch and brake, based on MRF damping character, were studied to widely use in many kinds of mechanical transmission systems for their particular advantage, such as easily controlled, no mechanical impact and low transmission noise, etc.In this dissertation, the numerical simulation and experimental test of the torque and temperature rising charactersitics of MRF damper has been verified, aiming to control winding tension constant, based on the support of the Natural Science Fund of Zhejiang Province and Natural Science Fund of Ningbo City, The Tension Control Theory and Experiment Research Based on MRF. On the basis of analyzing the mechanism of tension produces in the winding system, some simulation and experiment of three control method are studied in the tension control system based on MRF damper. The control method includes PID, fuzzy PID and BP neural network.Firstly, the composition, MR effect and the character of MRF, being used in the dissertation, is introduced. The relation function between yield stress and intensity of magnetic field is achieved. Utilizing the Bingham model of the MRF, the damping torque model of MRF damper is set up. The magnetic field model of designed MRF damper is analyzed through ANSYS software. Based on the model of the damper torque produced by magnetic field, the torque output by damper is computed though numerical simulation with four kind of damp clearance when the current changes from 0 to 1.5A. The output rule of magnetic induction intensity and torque under different clearance and current are analyzed and compared. Based on the numerical simulation, the damper used for the tension control is designed and made. Then some experimental test is finished on the damper performance test platform. The relation of input current and output torque is validated. The results of numerical simulation and experiment test are coincident to prove that MRF damper can be used as the execution component of tension control though controlling the current to change the torque.Based on the heat produced mechanism, combined with the torque model, the heat produce speed is established on the damp clearance. The finite element temperature field of three kind of damper structure based on ANSYS heat analysis model are compared though numerical simulation. The temperature field's distribution and changing law of MRF damper is achieved when the damper is working. One kind of logical decreasing heat structure is confirmed. A new type of MRF damper with water cooling structure is designed and made.The results of numerical simulation and experiment test to different structure of MRF damper show that the temperature of MRF damper will influence the output torque and MRF's performance. The temperature rises continuously without the cooling measure, and the time reaching the steady temperature state will very long. The experiment result shows that the MRF structure has been destroyed when the temperature exceeds 90℃, and the damper can not work again. The steady temperature state will come early if the cooling structure is set up., and the temperature of the steady state is less than 60℃. The damper with cooling device can run in tension control system continuously.Based on analyzing the component of the general winding system, static and dynamic tension changes are studied. The mathematics model of tension shows that the torque produced by MRF damper can control the tension changed. After simplifying the expression of tension, the tension, which is influenced by winding radius, rotate speed and control current, is numerical simulated,. Numerical simulation shows that the tension influence of winding radius, rotate speed and control current is nonlinear.Aiming to test the tension control system which the MRF damper acting as executor, three control arithmetic are designed, including the classical PID control, adaptive fuzzy PID control and BP neural network control. After analyzing the control system of PI and PI based on PD feedback in detail, the damping ratio caused by them is compared. The application of adaptive fuzzy PID control and BP neural network in the tension control system is introduced. The structure of BP neural network model is designed, and parameters of input layer and output layer of BP neural network are confirmed.In order to testify the application of MRF damper can be used in the tension control system, an experimental device based on MRF damper is built. The device is composed of servo motor, speed reducer, rotate speed and torque sensor, MRF damper, flexible tape rolling wheel, tension sensor and so on. Using the industrial computer as the control center, tension and rotational speed data is gathered in time through PCI-6221 data acquisition card. Tension monitor software is established in LABVIEW to display and save data. The software system includes data acquirement and processing. The designing of three control arithmetic, and so on. After parameters of PID and fuzzy PID control are confirmed, control experiments are tested on the experiment device. The test result shows that PID control can play a certain amount of control effects although the system is non-linear when the winding radius is smaller, the PID parameters being adjusted by fuzzy control timely, the control result is better. The best control result can be realized though BP neural network after being trained.Experimental results show that the MRF damper can be used as the executor to control tension. The tension fluctuations can be adjusted to smaller through the system.Finally, a comprehensive summary of the study and achievement is indicated in the dissertation, and the further engineering application prospects are pointed out.In order to restrain the temperature of the MRF damper being raised, a new MRF damper with water cooling structure is designed. The new MRF damper provides a new approach to extend the serving time. The MRF damper being used in tension control system, controlled by classical and intelligent control method, broadens the application of MRF, provides a new approach of tension control.