A few application of linear electric machinery in numerical control machine tool

   The history of linear electric machinery is OK the not successful shows embryonic form slightly linear electric machinery that Hui Sideng made restrospect to 1840, ever since 160 old in linear electric machinery experienced exploration to experiment, development applies and use commercialization 3 period.  

   Came 1971 at present, linear electric machinery enters the period of independence application eventually, the application of of all kinds and linear electric machinery got rapid promotion, made a lot of unit that have economic value and product, for example all sorts of machine of coal of the steel tube conveyer of drive of linear electric machinery, carry, dynamoelectric doors, dynamoelectric window. Use the train of magnetism in suspension of drive of linear electric machinery, speed already exceeded 500km/h, approached the rate that aviation flies.  

   The research of the linear electric machinery of our country and application are from 20 centuries begin at the beginning of 70 time. At present main achievement has hammer of factory drive a vehicle, electromagnetism, punch to wait. Although research of our country linear electric machinery also obtained a few result, but compare with foreign photograph, its popularize applied respect to still be put in very big difference. Current, home studies the unit already noticed this not less [1] .  

    The current situation that linear electric machinery uses on numerical control machine tool 

    In last few years, to numerical control the machine tool uses linear electric machinery to appear particularly popular on international, its reason is:  
  
    Fast treatment shows develops to improve manufacturing efficiency and the treatment quality that improve a spare parts high speed and freeboard to already made a when the machine tool develops major trend, delicacy of a reaction, high speed, portable drive system, rate should rise above of 40 ~ 50m/min. Traditional ” rotate electric machinery + ball guide screw ” the highest feed rate that transmission form can achieve is 30m/min, acceleration is 3m/s2 only. Workbench of drive of linear electric machinery, its speed is 30 times of transmission way more traditional, acceleration is 10 times of transmission way more traditional, can amount to 10g most; Stiffness raised 7 times; The workbench of direct drive does not have linear electric machinery retrorse job dead band; Because electric machinery inertia is small, the linear servo that forms by its so can achieve taller frequency to answer.  

    1993, german ZxCell-O company rolled out the first by machining center of the workbench HSC-240 of drive of linear electric machinery high speed, machine tool main shaft is highest fast achieve 24000r/min, speed of the biggest feed is 60n/min, acceleration achieves 1g, when feed speed is 20m/min, its outline precision can amount to 0.004mm. The company tightened American Ingersoll to roll out machining center of HVM-800 high speed then, main shaft is highest rotate speed is 20000r/min, speed of the biggest feed is 75.20m/min.  

Began 1996, machine tool of the horizontal machining center that Japan develops a success to use linear electric machinery in succession, high speed, freeboard fast small-sized machining center, exceed rigid lens face to machine machine tool of figuration of machine tool, high speed to wait [1] .  

    University of our country Zhejiang developed a kind by the punch of drive of linear electric machinery, the shunt-wound orgnaization coordinate that manufacturing engineering institute designed Zhejiang university to use drive of cylinder linear electric machinery is measured machine [2] . Nanjing quarto company rolled out what develop by oneself to use linear electric machinery 2001 the numerical control of direct drive is linear electric locomotive bed, 2003 on exhibition of machine tool of the 8th China International, showpiece the machining center that the VS1250 linear electric machinery that joint-stock company of hi-tech of Beijing report courtyard rolls out acquires, main shaft of this machine tool is highest turn up 15000r/min.

  The working principle of linear electric machinery

   Linear electric machinery is one kind changes electric energy into sharp movement mechanical energy directly, and the gearing that does not need any intermediate changeover orgnaizations. It can regard as to rotate electric machinery presses radial sliver, exhibit plane and become, if pursue,1 place is shown.

Graph the transition process of 1 linear electric machinery

   A side that evolve by stator and comes is called primary, a side that evolve by rotor and comes is called sub. When applying actually, will primary and sub make different length, journey range needs in order to assure in place inside primary with sub the coupling between keeps changeless. Linear electric machinery can be short first monitor is sub, also can be long primary short sub. Considering production cost, moving charge, all use commonly at present short first monitor is sub.

   The working principle of linear electromotor and rotate electromotor is similar. It is with linear induction motor exemple: When primary winding tells alternating current source, produce travelling wave magnetic field in air gap, sub and be expert at below cut of wave magnetic field, give the response electromotive force and produce electricity, the action of magnetic field photograph in this electric current and air gap produces electromagnetism thrust. If primary and fixed, sub linear exercise is done below thrust action; Conversely, primary do linear exercise.

   The drive of linear electric machinery controls a technology

   System of application of a linear electric machinery should have the linear electric machinery with good performance not only, still must have the control system that can implement technology and economic demand below the condition of on the safe side. As the development of automata technology and small computer technology, the control method of linear electric machinery is increasing. The research that dominates a technology to linear electric machinery basically can divide for 3 respects: It is conventional control technology, 2 it is contemporary control technology, 3 it is intelligent control technology.

   Traditional control technique if the PID feedback control, control that solve Ou wide application received in communicating servo. Among them the past in process of control of trends of PID control contain, mix now prospective information, and configuration is almost best, have stronger rash club sex, it is the most fundamental control pattern in communicating system of drive of servo electric machinery. Dominate the result to rise, often use the control that solve Ou and vector control technology.

   In object model affirmatory, indeclinable and be linear and operation condition, moving environment is affirmatory below changeless condition, using a tradition to control a technology is simple and effective. But the high-powered circumstance in high accuracy small feed, with respect to the change that must consider object structure and parameter. All sorts of nonlinear influences, when waiting, the change of moving environment and environmental interference change to decide factor with inaccuracy, ability gets satisfactory control result. Accordingly, contemporary control technology caused very big attention in research of pilot of linear servo electric machinery. Method of commonly used control has: Change from adaptive control, slippery model structural control, rash club control and intelligent control.

   In recent years the intelligence such as ambiguous and logistic control, nerve network control controls a method to also be introduced in the control of system of linear electromotor drive. Basically be ∞ of network of will ambiguous logic, nerve and PID, H at present the control method photograph of the existing maturity such as control is united in wedlock, learn from others’s strong points to offset one’s weakness, in order to acquire better control property [3] .

   Linear electric machinery uses example mediumly in numerical control machine tool

   Vivid traffic jam cuts numerical control system

   Because the sharp movement orgnaization that uses linear electric machinery is had answer the characteristic with fast, tall precision, in the CNC turning that uses Yu Yi sectional work successfully and grinding treatment. Be aimed at the blame with the biggest crop round sectional spare parts, the high frequency ring that cutting research center developed circle of blame of university of national defence science and technology to be based on linear electric machinery is big feed of journey numerical control is unit. When be used at machine tool of numerical control piston, workbench dimension is 600mm × 320mm, journey 100mm, the biggest thrust is 160N, the biggest acceleration can amount to 13g. Because mover of linear electric machinery and workbench already were secured together, can use closed-loop control only so, the graph shows the control system diagram that is this unit 2 times.

Graph the principle block diagram of controller of position of 2 linear electric machinery

   This is system of a double closed circuit, core is speed annulus, outer shroud is positional annulus. Use feet of high accuracy grating to regard the position as detecting element. Fixed position precision depends on the resolution of grating, mechanical error of the system can be eliminated by feedback, obtain taller precision [4] .

   Use the system of open mode numerical control of linear electric machinery

Use PC and open formula but controller of result of process designing carry makes numerical control system, this kind of system is platform with general personal computer and Windows, the athletic controller of the form of standard plug-in unit that goes up with the PC is control core, those who implemented numerical control system is open. The overall design program of the system of open mode numerical control that is based on linear electric machinery is shown 3 times like the graph.

Graph the principles of 3 system of open mode numerical control that are based on linear electric machinery pursue

   This system uses the plan composition that inserts motion to control card in the patulous chamfer of the PC, the system controls the part such as workbench of driver of card, servo, linear electric machinery, numerical control to comprise by PC, motion. Numerical control workbench by drive of linear electric machinery, servo is controlled and control of machine tool logic all is finished by athletic controller, athletic controller but process designing, control a process in order to carry the means explanation of mover program executes number (G code, supportive user is patulous) . Motion controls calorie of model to be PCI-8132.

   Current industry controlled bus line of the PCI in the technology to replace ISA bus line gradually, form of predominate bus line, it has a lot of advantages, like Plug and Play (Plug And Play) , interrupt share etc. PCI bus line has rigid standard and standard, this made sure it has good compatibility, reliability is high; Deferent data rate is high (132Mbps) or (264Mbps); PCI bus line and CPU have nothing to do, have nothing to do with clock frequency, apply to all sorts of platform, support multiprocessing implement with collateral job; PCI bus line still has good expansibility, adopt PCI_PCI bridge way, can undertake multistage expands. PCI bus line offerred huge to go to the lavatory for the user, it is current a kind of the the most advanced, most current bus line on the PC. PCI-8132 is the card of control of 2 axes sport that has PCI interface. It can produce pace of drive of high frequency pulse to enter electric machinery and servo electric machinery, the electric machinery that dominates 2 axes moves, implementation is mixed point-blank circular arc interpolation. In numerical control treatment, offer positional feedback.

   Systematic software is developed on WINDOWS platform. This software is used modular programming, by the user the input outputs the interface, composition such as pretreatment module. Interface of user input output realizes the output of the input of the user, system. The main function that the user inputs is to let an user input numerical control code, issue control order, undertake systematic parameter is configured, create machine program of spare parts of numerical control machine tool (G code dictates) . Pretreatment module is read after taking G code to dictate, generate through compiling can let PCI – the program that card of 8132 sport control runs, thereby drive is steep electric machinery, finish linear or circular arc interpolation. Reading the course that takes G code is the set that has parameter above all, read next take G code, if the graph is shown 4 times,this order flow is as follows.

Graph 4 read take flow chart of G code program

   PARKER406LXR series is chosen in this one system linear electric machinery. To workbench of two coordinate numerical control, x to choose 406T07 linear electric machinery, journey 550mm, y to choose 406T05 linear electric machinery, journey 450mm.

   Epilogue

   Use the high speed machining center of linear servo electric machinery, already made the crucial technology that manufacturer of each big machine tool studies eagerly on international and develops and product, already obtained initial application and result in auto industry and aviation industry, as the new generation of high speed machining center direct drive servo carries out component, electric machinery technology is in linear servo to also had entered industrialization application phase domestic and internationally. But, home still is in in the research of this respect start level, difference is very big still, the article was made in the applied respect of linear electric machinery a few discuss, a lot of technology issues still remain the effort henceforth.