The Technology Research On Vibration Damping Of Machine Tools Based On MRF

The modern machinery manufacturing technology is developing towards high precision,high production efficiency,high machining quality and manufacturing automation technology,but the main factor of restricting the development is vibration of machine tools,in the process of machining,the harm of machine tool vibration mainly displays in: All kinds of forming movement of the process system subjected to the interference and destruction,the machining surface appeared in the chatter mark,increased the roughness value,deteriorated to the machining surface quality,and optimize the service life of cutting tools,machine tool and fixture using time;due to an increase in the amount of cutting by mechanical vibration,which is to lower production efficiency,or lead to the end of machining;in terms of workers' health,vibrating very bad noise pollution.In the field of mechanical processing,this paper discusses such as process system vibration resistance and eliminate vibration,mechanical vibration mechanism,has been a important subject.But machine tool vibrancy,noise and control of basic technology and application of the technology is weak at present.Whether the low-frequency machine tools for reducing vibration and noise such as for punching machine,forging machine or the high-frequency machine tools such as for precision and ultra-precision machine tools,has important significance in practice.vibration-reducing has become the key technology that guarantee the machining quality,high precision and low surface roughness,to ensure the machine working smoothly and reliable.This article is in view of this problem of the machine tool vibration is beginning to study,put forward the magneto-rheological damping technology used in machine tool vibration,the introduction of new intelligent materials of MRF damping,developed a variable damping,realize the semi-active fuzzy control of magneto-rheological damping of the machine tool.In view of processing requirements of modern machine tool that the high precision,high speed,high efficiency,the magneto-rheological damper of from theory and experiment two aspects is beginning to study.In-depth,comprehensive study of the various properties of MRF is accomplished by a test of two kinds of MRF samples.The relation between static and dynamic shear off the constitutive,established the relationship between the shear yield stress,the viscosity and shear rate and he relationship between the shear yield stress and magnetic field strength,It provides the basis for structure analysis and design of the magneto-rheological damper;according to the actual project confirmed the magneto-rheological damper of structure about a double lever shear valve mode,according to the theoretical formula,determine the main parameters of the structure;this paper set forth the theory of electromagnetic field and analyzed the parameters of magnetic field and magnetic circuit,the relationship between the I and H of magneto-rheological damper clearance of the theoretical value and the relationship between the I and H experimental values are compared and fitted,theoretical analysis is correctly.The dynamic model of magneto-rheological damper was established.analyzed the typical mathematical model,such as Bingham model,Bouc-wen correction model,the nonlinear hysteretic model etc.,not well simulate the nonlinear dynamic characteristics of magneto-rheological damper,or excessive parameters is not convenient for numerical processing etc,and points out the flaws of the model.combining the neural network algorithm,modeling steps are given,and a calculating example shows that this method can accurately predict the actual damping force of magneto-rheological damper.under the condition of the same frequency and the same current and the condition of large amplitude,the damping force is larger that is one that gets results.The manufacturing and performance of MR damper were tested,the results show that the hysteretic curve of the damper is full and has the characteristics of strong damper,damper forc adjustable coefficient with the change of current can be adjusted continuously,The damping force can be adjusted to about 30.Put forward the magneto-rheological damper is used to machine tool system of vibration,work out magneto-rheological damper of machine tool.by the algorithm based on semi-active fuzzy control,in order to realize the decrease of the machine tool vibration amplitude,mobilize the rigidity and damping of the magnetorheological damper parameters,it can effectively reduce the amplitude of machine tool vibration and suppress the vibration of the machine tool.Therefore,it provides a strong guarantee for processing quality of precision and ultra precision machining.Set the magneto-rheological damper semi-active fuzzy control system experimental platform.From the simulation result shows that machine tool vibration reduction system of optimal damping ratio should be controlled at 0.26.according to the actual condition of the machine tool vibration,through the semi-active fuzzy control algorithm,can adjust the damping ratio of the system,and real-time achieve well vibration damping effect.The experiments indicate that: machine tool cutting process of the amplitude with magneto-rheological damper compared with the amplitude without magneto-rheological damper is reduced by 28.8%,and the root mean square is reduced by 20.7%.This research is design magneto-rheological damping device based on the fuzzy control algorithm,has significantly reducing vibration effects.For the XD-30 vertical CNC milling machine,a five-freedom dynamic model of the machine tool is set up,as dynamic characteristics of machine tool,the best match of machine tool and magneto-rheological damper,optimal control of the machine tool vibration laid a theoretical foundation.This paper puts forward new magnetorheological damping machine tool vibration reduction system of fuzzy controller,the basic principle of fuzzy control and fuzzy controller is analyzed,due to the nonlinear characteristics of the magnetorheological damper,input different signals will lead to the change of control parameters,and we can't accurately identify or measuring these parameters.Oriented the model of the traditional control strategy,relying on the linear model of the object.When faced with the actual mechanism time-varying uncertainty and nonlinear characteristics,these conditions significantly affect the implementation of this method.In view of the realistic need,which the machine tool vibration control,and puts forward the ceiling control,PID control and fuzzy control strategy,and the three kinds of control strategies are tested on the effectiveness of the actual machine tool vibration control study,through the magnetorheological damper experiment validation,fuzzy control strategy for damping effect is remarkable.In this paper,we detailed research of several key techniques of design of fuzzy control on the damping device of Machine Tools based on magneto-rheological fluid,such as the properties of MRF,the dynamic model of magneto-rheological damper,the technology of semi-active fuzzy control,modeling system of machine tool,based on the magneto-rheological damping vibration experiment of machine tool.The work has important guiding significance and reference value to the vibration of the machine tools effectively.