Research for the Electro-mechanical Coupling of Series Mechanism of Virtual Axis Polishing Machine

With the development of the integration of the world economy and IT industry, it has taken place great revolution in the environment of modern manufacturing enterprise, the Virtual Axis Machine Tools is considered the 21th Centuary’s machine tool. The study of electromechanical coupling can establish a foundation for widely application of Virtual Axis Machine Tools. The development and application of Virtual Prototyping Technology provide a technical means for the exploitation and research of NC Machine Tool. How to apply virtual and simulation technology to solve the key problem of machine tool is key in the field of machine tool. The virtual axis polishing machine tool that is exploited in Jilin university and used to polish free-form surface is applied as a study object. Use the software of ANSYS, ADAMS and MATLAB as tools to analyze the problems about virtual axis polishing machine. According to the characteristics of serial mechanism, put forward static-dynamic simulation control theory based on Virtual Prototyping Technology, study the application of virtual prototype technology in virtual axis machine tool, propose a kind of parallel controlling strategy based on CMAC and PID, and study the characteristics of mechanical transmission and electromechanical coupling. By introducing virtual technology to the study and analysis of virtual axis machine tool, provide a new technology platform for the widely using of this new type machine tool.1.On the base of analysis of machine tool structure, draw the model of series mechanism of virtual axis polishing machine tool by using CATIA, which contains dynamic platform and tool. Simply the model in order to analyze conveniently, establish and assemble the solid models of each part of mechanism. The series mechanism is as follows Fig1. Fig1.series mechanism of virtual axis polishing machine2.Constraint each component of virtual axis polishing machine tool by using SimDesigner in CATIA V5. Measures the motion path of polishing tool in the polishing machine tool and analysis the motion characteristics of series mechanism of virtual axis polishing machine tool under working of the servo-motor. The analysis results of ADAMS is as follows Fig2. Simulation analysis show that the mechanism has the properties of well acceleration performance , shorter time of adjustment, accurate and fast implementation. Fig2.The force,torque,displacement of cutterhead in working of servo-motor3.The precision of series mechanism will directly effect the precision of whole machine tool. This thesis conduct a static-dynamic analysis of series mechanism. For convenient analysis, deal with models by means of deleting some modified characteristics, such as chamfer, lug boss and keyhole that will not effect the mechanism significantly. Lead the models to Software ANSYS and come on its previous 12 order frequency and vibration mode . Fig3 is First Order Modal Logic, it is clearly that the around area of polishing tool has big deformations under the effect of servo-motor. Fig3.The first order mode shape of series mechanism of virtual axis polishing machine4.Motor torque is the input of the modal and exercise volume of polishing tool is output. Draw out the kinetic curve of polishing tool based on the simulation by use of software ADAMS and MATLAB. The polishing tool can work stably in short time and the flutter of polishing tool can satisfy the processing precision’s requirement by way of analyzing the motion of series mechanism. Fig4.The cutterhead’s flutter force under effect of two driving force based on MATLAB5.Put forward a parallel control method of CMAC and PID aiming at the nonlinearity and various uncertainty existing in high precision servo systems. Study the electromechanical coupling prosperities of high-precision mechanical drive in servo systems based CMAC and PID, establish the coupling modal of servo systems and simulate the structure by use of MATLAB/Simulink. The results show that the method overcome some disadvantages that common controller can’t avoid, improve the control effect, fasten control corresponding velocity, satisfy the tracking accuracy’s requirements and fully embody cerebellum model’s characteristics, such as minor error, strong robustness. The research has considerable reference value in Engineering in improving the high precision dynamic tracking of servo systems.

Study on the Catalysts and Process for Direct Synthesis of Dimethyl Ether from Syngas

Dimethyl Ether (DME) is not only an important chemical, but also can be converted into liquefied petroleum gas. Furthermore, DME is also an ideal substitute for diesel or liquefied petroleum gas. So, the application prospect of DME becomes wider. In recent years, the synthesis process of DME has attracted much attention in research fields and industrial field.The syngas, which is produced commercially by steam reforming of natural gas or coal can be converted into DME. As well known, coal resource in China is very rich, production of DME from coal is an important option for the efficient conversion of coal into clean fuel.The conventional process of DME production, named two-step method, has become more and more insufficient with the growing demand for DME as fuels for new applications. Lately, an original technique named one-step method was developed for the direct synthesis of DME from synthesis gas in a single reactor. Compared with the conventional method, the one-step method is attracting more and more industrial attention from industry because of its dramatically economic values and theoretical significance.The synthesis gas directly convert into dimethyl ether by using fixed – bed and high – pressure flow apparatus. In this paper, the catalyst and process of dimethyl ether from syngas were studied.Firstly, a series of catalysts were prepared with mechanical mixing method. These catalysts were investigated by means of XRD, BET and NH3-TPD. The methanol synthesis catalyst and methanol dehydration catalyst were tested, which resulted in the conclusion that the optimal catalyst is C207/HZSM-5=4:1 (weigh ratio), and the ratio of Si/Al of HZSM-5 is 50.Secondly, the effect of temperature, pressure, space velocity and reduction temperature were discussed, then the optimal reaction conditions were optained: T=275℃, P=5.0MPa, SV=1600h-1, reduced temperature is 300℃. The conversion of the CO is above 90%, the yield of the DME is above 70%.

Research on Heat Treatment Technique for Forged Grade E Steel Coupler Yoke

With the increase of traction load and running speed for train, the fracted failure of casting coupler yoke rise significantly, which brings severe secure incipient fault to railage, and improving coupler yoke’s property has become one urgent problem to resolve.Heat treatment technique of forged grade E steel coupler yoke has been studied in this paper, in which the real-time temperature measuring method is utilized to determine the reasonable heat treatment regulation for mass production of forged grade E steel coupler yoke and heat treatment parameters are optimized by using the software based on optimization design method and computer simulating test. Meanwhile, quenching technique of forged grade E steel coupler yoke has been studied and the quenching tank with the agitated control system used in forged coupler yoke’s quenching is designed.The research results show that the heat treatment regulation which has been determined by the real-time temperature measuring method is scientific and reasonable. After heat treatment on the basis of this regulation, the microstructure of forged coupler yoke is symmetrical tempering sorbite and the microstructure and mechanical properties meet the need of railway. The strength of grade E steel treated by optimized parameters has raised by 8.3% at high plasticity level. The quenching tank with the agitated control system can control the cooling speed of workpieces,improve and stabilize the quenching quality of workpieces. Research on heat treatment technique of forged grade E steel coupler yoke provide new ideas and technical direction to other heat treatment technology and workpieces.

Detecting the Quality of Raw Milk with the Homemade Impedance Tester

As the Basic material of milk manufacture, the quality control of raw milk is the substantial step in the whole quality control. If this step occurs problems, no matter how advanced the next control method is and how strict the control instrument is, we will only get half the result with twice the effort. Milk is a kind of well-fed food. These nutrition is extremely good for microbe’s growth and reproduction. Therefore, detect raw milk’s aerobic bacterial count is one of the most important indexes of milk quality’s detection. The traditional method of detecting aerobic bacterial count is agar counting which operate fussily, need 48 hours’detect time and count with naked eye can be easily influenced by environmental factors and influence economic efficiency of milk manufacture. In this thesis, Basic research has been done about detecting aerobic bacterial count in the raw milk with homemade impedance detector. Introduce homemade impedance detector’s work principle, tester’s configuration and test parameter’s enactment; analyse the effect of the sample’s cubage, raw milk’s protein content, fat content and aerobic bacterial count on detect result of impedance detector; do research about the change rule of aerobic bacterial count and detect time in raw milk; detect the time when raw milk’s resistance and electromotive force achieve threshold, combine linearity regress theory and method, build linearity regress mathematical model and standard curve of aerobic bacterial count and detect time; make contrast experiment with impedance detector and the method of agar counting to detect aerobic bacterial count in raw milk, make compare analysis to the two results. The main conclusion as follows:(1)The homemade impedance tester is used to detect the bacterial totall of the milk which is placed different days in the room. Checking the electromotive force and resistance of the sample milk get DT1 and DT2. The conclusion as follow: 1) With the milk’s bacterial total increasing, the DT1 which checking the electromotive force gets is reduced gradually. The reason is that if the cow milk is polluted by the bacteria, along with oxygenic being consumed an the reductive metabolizable production coming out, the redox force is fallen down gradually. So along with the bacterial total of the cow’s milk increasing, its metabolism quickens gradually, the electromotive force reduces more quickly, the time when the value is reached is more short.2) With the milk’s bacterial total increasing, the DT2 which checking the electromotive force gets is reduced gradually. The reason is that when the bacteria reproduce ,the nutrition element (for example the lactose, the protein, the fattiness) of the raw milk, the big molecule substances is coverted to the small molecule substances (lact-salt or ammonia). The milk’s resistance gets reduced. So along with the bacterial total of the cow’s milk increasing, its metabolism quickens gradually, the resistance reduces more quickly, the time when the value is reached is more short.(2)The variety of lactose、fattiness、protein’s content in the raw milk is no influence for the detected results. The DT’s error is between±0.03-±0.07h. The reasons as follow:1) They aren’t quite sterilized, so they are likely to take bacterial. Or when the milk is shared, it is polluted outside. Consequently, the DT become short.2) When the milk is being detected, it is mixed other bacteria, or disturbed from environment(for example the tremble, too high sound). These are the reasons that the error come out.(3) The standard curvilinear is set up and validate experimentantion, the conclusion as follow:1) The research indicates that the detect time DT received by testing sample milk’s resistance and electromotive force with impedance detector is shortened gradually as the aerobic bacterial count increased, that is the high aerobic bacterial count is, the smaller DT is.2) The research indicate that according to the principle of electric impedance detect method, test the electromotive force and resistance in sample milk and receive detect time DT1, make regression analysis with these received data, build standard curve and the regression equation is y? = 10.3671?0.6924x. Make hypothetic test of significance to regression equation and regression coefficients using F detect method, the results are all marked. Receive correlation coefficient r1= -0.9590, that is the relation of aerobic bacterial count and DT1 is high negative correlation.3) The research indicates that according to the principle of electric impedance detect method, test the electromotive force and resistance in sample milk and receive detect time DT2, make regression analysis with these received data, build standard curve and the regression equation is y? = 10.2728?0.6745x. Make hypothetic test of significance to regression equation and regression coefficients using F detect method, the results are all marked. Receive correlation coefficient r2= -0.9481, that is the relation of aerobic bacterial count and DT2 is high negative correlation.4) The research indicates that by the 7 parallel test of three quantitative level, validate the two above regression equation, make hypothetic test by t detect method, the result shows that the aerobic bacterial count detected by the two methods is the same as detected by the method of agar counting. The innovation of this thesis is:Using homemade impedance detector to detect aerobic bacterial count in the raw milk;Using homemade impedance detector to test electromotive force and resistance in raw milk, build two standard curves.

A Research and Application of the Quality Traceability System in Heavy Casting Process

China, whose casting output occupies head of the world, is the great casting nation in the world, but compared to developed countries, our casting quality level still has a very big gap. At present, many domestic casting enterprises have been qualified for ISO 9000 quality system, but it never has been really applied into actual production. How to apply the theories and methods of quality management and control into casting production specifically and suitably, and to make the quality management land on feet , and finding out management methods suitable to national condition are urgent matters of present casting enterprises in domestic, and also have the profound significance to the development of our casting quality and the overall level of our casting industry.In this thesis, the research object is casting process of Erzhong foundry factory. First, existing quality management of foundry factory and quality problems in casting process have been analyzed. Then, the paper proposes applying traceability technology to the casting quality control and constructs casting quality traceability system, and also builds and implementsThe following is the main contents of the dissertation:①Casting quality and its available quality control are introduced, and present statue of casting quality control in domestic and foreign is summarized. Then, the main contents of the dissertation and its significance are presented.②The product structure and casting process are discussed and existing quality management of foundry factory and quality problems in casting process are analyzed. a Summary is made on frequent quality problems of casting and the reasons are analyzed.③The traceability technology is applied into casting quality control to construct a casting quality traceability system. And the implementation thought、construction and key technologies are presented.④The establishment and implementation of the casting quality traceability information system are stated, including analysis of the system functions and design of module、design of the database and the implementation of the database’s structures.Finally, a summary of the research work and the results is made, and plans for future research are presented.

Study on Project Risk Assessment Theory and Its Application in Oil Pipeline

This paper applies project risk assessment theory to oil pipeline risk assessmentpractice. The development and current status of oil pipeline risk assessmenttechnology are generally introduced both at home and abroad. Especially, Kent indexassessment model is analyzed in detail, which nowadays is widely used in pipelinerisk assessment practices in China. Although the Kent model has many advantages,there are some shortcomings especially in weights for the first rank assessmentindexes. Inoriginalmodel,weightsofthefirstrankassessmentindexesaresetequally,which is not consistent with practical situation in China. Reliability engineeringtheory and statistic method are used to improve this shortcoming in this paper. Inordertomakethisimprovementmorefeasible,experts’opinionsshouldbeconsideredlater.In order to solve the problem that assessment results may be distorted by riskestimators’subjectivity, the grey evaluation model is used to assess project risk. Inthis paper, effect analysis on the two whiteness functions is conducted based oncomputer simulation, which are widely used in the grey evaluation model at present.The result shows there are drawbacks in both of them, which make the results of themodel incorrect. Thus, the paper proposes “three-step method” to set linear whitenessfunctions, and re-sets linear whiteness function. It is proved by computer simulationthat this improvement has made better effect. In further study, it is found thatevaluation effect of this model is relavant to power exponent of the whitenessfunction.Based on the study above, whiteness functions with different powerexponents are used when implementing grey evaluation model, which is called”improved grey risk evaluation model”in this paper. Finally, the paper demonstratesthe evaluation process of”improved grey risk evaluation model”through a case ofrisk assessment for gas pipeline, which shows improved model is more accurate andreliable.

Analysis on Three-point Sphere Brace of Converter by Finite Element Method

This topic is one of research contents which 150t converter design of some steel mill includes. Three-point sphere brace is the junction device of the converter furnace shell and loop. It plays an important role during the process of converter. Besides fixing the furnace body sturdily in the circle, it also can transfer the converter load safely to the loop and permit the furnace body to expand or contract freely in the radial and axial direction. However, in the steel-making process, the working condition of three-point sphere brace is extremely bad. Not only it must withstand gravity coming from the furnace shell and the molten steel . but also it must receive the heat convection influence as well as the impact load of converter in the process, so it is easy to be destroyed.According to the destroying reason of three-point sphere brace, this paper evaluates a multi-physical field thesis for key components of it using large finite element analyzing soft ANSYS. The development work in the article includcs:(1) Setting out from the temperature environment of three-point sphere brace, carry thermodynamics analysis to underside sphere surface seat and under sphere surface pad. Having confirmed the temperature distribution of model, providing temperature distribution results for thermodynamics and stress coupling field analysis;(2) to carry the contact analysis on key components of three-point sphere brace .which consist of underside sphere surface seat and under sphere surface pad . Found out the unreasonable structure from the stress situation. Proposed the improvement program. The stress concentration reduces obviously after the analysis is recarried . I laving achieved the anticipated effect;(3) Considering the modality analysis of key component of three-point sphere brace to determine the natural frequency and the vibration form of the structure. Taking the essential measure to avoid nonessential losses as a result of resonance factor in the use process;(4) Carry on the harmony response analysis to key component of three-point sphere brace to calculate out the corresponding value of the structure under several kinds of frequencies functions and draw the corresponding value curve to frequency. Thus, we can forecast structural sustaining powercharacteristic and confirmation whether the design can overcome the harmful effect because of the vibrates which resonate, weary and so on causes.The research result indicates that there is tress concentration in three-point sphere brace during the process and it works out of resonance. The stability capability is very good.

KPI System Design Based on BSC for Y Co.ltd’s Department

From the midst of 1990s, facing the broad market and lower labor cost, many international tyre groups step into china to establish producing bases through the way of single-venture or joint-venture. With the quick increase of market share and development, the china tyre enterprises are facing unprecedent challenge. In such a situation, if a enterprise want to get competitive advantage, he must improve his holistic performance.Facts proves that as the key function of human resource management, performance management is a significant management way to improve enterprise’ s performance. but in fact, there are many problems in many tyre enterprises especially the small and medium-sized enterprises, which blocks their developing.With a full awareness of present Y Co., Ltd’ s operation state and the problems in performance evaluation method, this thesis puts forward a research subject centered on this company’ s key performance index system based on Balanced Score Card theory. In the process of this research, performance management related theories、value chain theory、competitive advantage theory and BSC theory are employed. Through analyzing the method of establishing performance index, the KPI based on BSC theory is put forward. Afterwards in order to implement this system, the process of establishing performance index system is explained.The theory-reality combination approach is utilized to analyze and explain the meaningfulness of designing a KPI system based on BSC theory for this company. Through a comparison analysis and the integration of the core thought of balanced scorecard method and critical success factors method, the key performance index system design method eventually comes to birth. In the design process of this key performance index system, quantitive and qualitative analysis method are introduced to affirm this company’ s differentia strategy through analyzing the company’s macro environment、industry environment and inner environment in order to know the company’s present external opportunities、external threats、internal advantages and disadvantages. The company should focus on the maintenance and exploit of radial tyre market, and keep up the sale on bias tyre. For the other tyre market, the company should exit. On such a position, the present strategy is to input research resource to accelerate the design of new products, which can satisfy the need of customers. Through the good market image and brand reputation, the company can be one of the famous tyre manufacturers. To confirm the company’ s present strategy objectives, the BSC is used to decompound the strategy. the strategy map is used to decompound the strategy objectives and finally the KPI of departments come birth. Through the research of index proportion and appraisal method, the index system is completed. The summary and suggestions are given at the end of the thesis.The thesis aims on designing a strategy-oriented performance management system to integrate the enterprise’s strategic objectives with employee’ s behavior, which will improve the core competency. Also it is expected to be model for other tyre enterprises to study and follow.

The Study of Milk Nutrient Component and Fatty Acid of Pastured White Yak in Tianzhu, Gansu

The milk performance of yaks with different birth,the contents of protein, fat, lactose, dry matter and ash in the yaks’milk were measured;the content of fatty acid in yaks’ milk fat was tested by GC-MS.The results were compared with the counterparts of holstein,scalper. The pasture yield of alpine pasture and the nutrient component of the pasture in Tianzhu Tibetan Municipality, Gansu,were studied, too.The milk yield increased with the increase of the yaks’ birth. After fifth birth; the milk yield tended to decrease; the milk yield of third to fifth birth yaks in Nannigou pasture was significantly higher than that of their congener in Daiqian pasture and Wushaoling pasture (P<0.05) ,and the mean milk yield of the former in July and August was higher than that of the two later;the pasture production in Nannigou was higher than those in Daiqian and Wushaoling .The higher milk performance of yaks in Nannigou was attributed to the higher pasture production in the pasture.The contents of fat and protein in yaks’ milk from the 3 pastures were not significantly different(P>0.05 ),while the contents of fat and protein in yaks’ milk were exetremly significantly higher than those of Holstein milk(P<0.01).The contents of fatty acids in yaks’ milk from the 3 pastures were not significantly(P>0.05),indicating that the conditions of the pasture have no effect on the contents of fatty acid in yaks’ milk.The contents of fatty acids in milk of 1 to 5 birth yaks were not significantly different(P>0.05),showing that the different birth yak has the same physiological mechanism of synthesizing fatty acid.Contrasted with the contents of fatty acids of Holstein milk,the contents of unsaturated fatty acids(USFA) in yaks’ milk were significantly higher(P<0.05) and the contents of saturated fatty acids(SFA) in yaks’ milk were significantly lower(P<0.05),resulting from different genes and feeding patterns.The contents of SFA and USFA and the ratio between SFA and USFA were 65.05%,34.95% and 1.86 in fading period. The contents of SFA and USFA and the ratio between SFA and USFA were 63.61%,36.39% and 1.75 in end of fading period. The contents of SFA and USFA and the ratio between SFA and USFA were63.09%,39.02% and 1.62 in buding period. The contents of SFA and USFA and the ratio between SFA and USFA were56.96%,43.04% and 1.32 in flourishing period.With the rising of temperature and the mature of pasture,the contents of SFA in yaks’milk were declining while the contents of USFA were increasing.

The Research on Changing Characteristics of Microbe Population in Activated Sludge

In this dissertation, by using the method of SBR in the lab condition, the domestic sewage was direct aerated in testing equipment. The activated sludge was cultivated step by step by controlling the environment conditions. During the process of cultivating activated sludge, the laws of change and biodegradation characteristics of microorganism population were emPH atically analyzed according to the experiment PHenomenon. Observed and analyzed large amount of zoogloeas which appeared during the process of cultivating. The influences of load on main microbe by changing the load were studied.The results showed that: 1. The activated sludge was cultivated successfully in lab by controlling the environment conditions. The microbe evolved from low-grade to high-grade during the process of cultivating. 2. During the process of cultivating, the effluent quality indexes changed with the change of main microbial community. At the early stage of cultivating, the free cells were the main microbe. The effluent effect was not good. The removal rate of COD is 40%, of BOD is 26.6%. The sludge settleability was not good enough in Aeration Tank, the value of SV30 is 1.3%.At the medium stage of cultivating, the swimming type of ciliates were the main microbe. The structue of sludge is compacter than at the early stage of cultivating. The effluent effect was improving. The removal rate of COD is 60%, of BOD is 64.5%. The sludge’s SV30 in Aeration Tank is 5%. At the late stage of cultivating, the Vorticella like protozoan appeared and became the dominant population. It marked the maturity of the activated sludge. The value MLSS achieved 1949.6mg/L. A large amount of branched zoogloeas made the flocs of activated sludge bigger. The removal rate of COD achieved 74%, of BOD achieved 74.2%. The sludge’s SV30 in Aeration Tank is 15%. The efficiency of sewage treatment is good.3. During the process of cultivating activated sludge, Branched zoogloeas appeared. The removal rate of COD increased remarkably. Branched zoogloea possesses stronger tolerance for water quality and shock loading ,which can enhance the reversibility of injured activated sludge.4. Observed the influences of changing organic load on main microbe, the results showed that high load can cause the nematode mass rearing, made the sludge abnormal and the effluent quality bad. Branched zoogloea possesses stronger tolerance for water quality and shock loading, so did not change.