The current situation of technology of drive of servo of numerical control machine tool and development trend

    One, overview

    Servo drive technology reachs one of technologies of key of pilot of other industry machinery as robot of numerical control machine tool, industry, in be paid close attention to domestic and internationally generally. In 20 centuries finally 10 years, microprocessor (especially digital signal processor — the further progress that the development of technology of DSP) technology, electric power electron, network technology, control technology is servo drive technology laid good foundation. If say 20 centuries,80 time are the word that technology of communication servo drive replaces technique of dc servo drive, so, 20 centuries 90 time are implementation of servo drive system complete digitlization, intelligence is changed, 10 years of network. This are in developed country of a few industry particularly apparent.

    2, foreign current situation and development trend

    Nobody are changed, dimensions changed production to raise high rate, high accuracy, efficient requirement to machining equipment, communication servo is had tall answer, maintenance-free (wait without carbon brush, commutator wear away yuan of component) , the characteristic such as high reliability, as it happens got used to this one demand. For example, company of company of company of Japanese FANUC company, electric machinery of 3 water chestnut, An Chuan electric machinery, German Siemens company, AEG company, Li Shile Indramat, American A.B company, GE company all be in early or late around will communicate servo 1984 Fu Zhu is practical. Technology of communication servo drive starts later, to 20 centuries 80 time end just has a product to come out. Like the ACS series of company of Hua Teng of academy of metallurgy ministry automation, Yangzhou 5308 factories introduce the 610 series of Siemens company, these products use high-power transistor module (GTR) , belong to imitate servo, but from the fill on the technology home is blank.

    Enter age of 20 centuries S” , of microelectronics workmanship become better day by day, make DSP operation speed shows geometrical number to rise, reached high speed of servo annulus road requirement of real time pilot, the periphery circuit that a few motion dominate chip manufacturer to still dominate electric machinery place to need (like A/D converter, position / speed detects generator of times frequency tally, PWM) as compositive as DSP kernel at an organic whole, make time of sampling of servo control loop achieves 100µs less than, by onefold chip implementation is added automatically, decelerate control, electronic gear synchro control, the digitlization compensation of 3 annulus controls the position, speed, electric current. The make a present of before a few new control algorithm are like speed, make a present of before acceleration, low wave that connect filter, cave filter wave be able to come true. On the other hand, the development of technology of electric power electron, make the switch frequency of cell of power of servo main circuit promotes 15 ~ 20kHz by 2 ~ 5kHz, 1GBT(insulation fence gate is bipolar transistor) reach module of IPM(intelligence power) the child that all is this one times, increased smooth stability of the system thereby, reduced systematic noise. Above the foundation that two respects are digitlization of communication servo implementation not only, and make communication servo tends miniaturization. It is OK perhaps that at present the servo production manufacturer of developed country of a few industries all basically can offer total number word to communicate servo cover suitably with oneself CNC system, like company of Japanese FANUC company, electric machinery of 3 water chestnut, An Chuan electric machinery company, pine issues company, Shan Yang company of company of electric machinery company, German Siemens company, Li Shile Indramat, Lenze company, American A.B company, Kollmorgen company, Relliance company, Baldor, PacificScientific.

    Total number word communicates the flying development of servo technology, make user basis laden state (wait like force of inertia, clearance, attrition) adjust parameter more convenient, also leave out the not stable element such as the drift that place of loop of a few imitate produces, but developing initial stage, servo interface lacks uniform standard, each manufacturer all design his interface circuit, mutual between without but interchangeability, the user is comfortable match relatively troublesome. Below the case that develops quickly in network technology and PC-basedCNC technology, this one problem is highlighted particularly.

    1987, raise level of international of digital drive interface by association of German machine tool and combination of Electric Energy Association of German electric power, namely SERCOS(SerialReal-timeCommunicationSystem is serial system of real time communication) interface regards data of closed circuit of system of high-powered sport control as communication interface of serial real time, the main manufacturer of system of electric machinery of these two association general, drive, CNC system forms group of a teamwork work. The company that joins SERCOS working group at first has a few companies such as AEC, ABB, AMK, Banmuller, Bosch, Indramat, Siemens, PacificScientific. Arrived 1994, the international standard that SERCOS makes controller and interface of system of digital servo drive is obtained as IEC61491 standard through, because this has open sex, heretofore member already added 70 many companies. Meanwhile, developed corresponding ASIC chip, SERCON816, transmission speed is 2/4/8/16Mbit/s, photograph of serial spot bus line compares SERCOS and other, available data transmission rate is high, for example when Ethement transmits data with 100Mbit/s speed, available data transmission rate is 5 ~ 10Mbit/s; When SERCOS transmits data with 16Mbit/s speed, available data transmission rate is 11Mbit/s. CAN(controllerAreaNetwork) is used at motion is controlled, must provide additional memory bumper and signal management resource, its cost is 2 times of SERCOS interface about, the fiber-optic noise that another characteristic is it controls capacity strong, transmission reliability is high. Although for CNC and digital servo interface development is eventually at the beginning of SERCOS interface, heretofore already was applied extensively at the interface between current campaign controller and digital servo. Already can satisfy inside 2ms at present, make a controller and amount to 32 servo to realize data communication. Network of servo of word of SERCOS amount to is spread a broad highway, can foreknow, be in not far in the future, the servo that contains SERCOS port will enter family, office, plant workshop and even each domains related to servo application. Company of Li Shile Indramat held market of drive of North America servo 1999 the portion of 10.5% , rank the first, it is this company on one hand in application project, sale, service reachs what the user backs an aspect to strengthen, another main factor is affirmatory and open structure — SERCOS.

    Pledge gently (wait like copper, lumber, aluminium alloy) , composite material is used in course of study of car, home appliance, AF in great quantities, raised new requirement to high speed, efficient treatment. To get used to this one demand, developed country of a few industry rolls out electric machinery of linear electric machinery, high speed main shaft in succession, and Fu Zhu is practical. To linear electric machinery, its control technology and traditional communication servo electric machinery are about the same, but wait for rotor without rotor as a result of itself of linear electric machinery, itself inertia is consequently small, have tall trends to answer a gender so, and detecting element is installed directly at mechanical a side, detect thereby the displacement of workbench, also avoided to rotate the inverting clearance that electric machinery exists when direction is changed, satisfied high speed, tall nicety to machine the requirement of pair of servo drive systems. From IMTS ‘ in light of 2000 exhibition, developed country of a few industry is in banner level in respect of high speed processing technique, IBAG company already offerred 0.125 ~ 185kW to industry, top rotate speed is 14, the seriation of 000r/min installs system of type main shaft inside high speed, radial, axial repeats precision to be less than 1µm, electric machinery bearing has bearing of mixture pottery and porcelain, liquid static press bearing of float of bearing, magnetism 3 kinds, use conduit refrigeration, and inside set buy sensor offers machining center ATC with. Main shaft drive uses technology of vector frequency conversion, already was in the domain such as treatment of treatment of treatment of mould treatment, tall accurate electrode, aluminous simple spare parts, high accuracy grinding applies extensively, fisher company also has similar product.

    3, domestic current situation and development trend

    Our country in 20 centuries 80 time initial stage is passed introduce, digest, absorb foreign advanced technique, be in again country ” 75 ” , ” 85 ” , ” 95 ” during undertake to servo drive technology project of great science and technology tackles key problem fetched very big gain. But the reason that waits for a respect as a result of product reliability, restricting the form a complete set of machine tool of our country numerical control and application, affect the development of manufacturing industry of our country equipment thereby. Manufacturer of a few machine tools also must choose foreign servo, make machine tool of homebred numerical control all does not prevail in the respect such as the price, date of delivery, dependability, more inadvertently force develops the new breed of market demand, lose huge market share thereby. From the point of public statistical data, the part of breakdown out servo of the 75% above in CNC system. However, in the country in recent years ceaseless organization science and technology tackles key problem while, company of high-tech of a few civilian battalion also is infuse of technology of drive of servo of development our country new vitality. For example below the circumstance that limited company of technology of automation of the Bao Lun in Beijing did not invest a minute of money in the country, it is with the market oriented, develop new product ceaselessly, developed servo of dc of successful PDC series 1994, torque shares the wide timing of 7 norms to sort servo electric machinery continuously to 44.1N•m from 1N•m, use the power parts of an apparatus of newest generation on international — control of IPM, PWM, modulation frequency achieves 15kHz, overcame effectively before the electric current when SCR is controlled is intermittent the inverting scintilla that produces the ablation to commutator, can make carbon brush life lengthens 1 times above. This company develops successful PAC series to communicate servo again by 1997, of 94 norms that introduce series of 1FT5 of German Siemens company with factory of Lanzhou electric machinery without brush communication servo electric machinery to be covered suitably. Rotate speed series has 1, 200r/min, 2, 000r/min, 3, 000r/min, 4, 000r/min, 4, 500r/min, 6, 000r /min, torque limits · of 0.15 ~ 90N; In November 2000 according to market demand, development goes PAC-P series to digitlize servo of the position communication. These products are pushed to market hind, obtained very good society benefit and economic benefits, get Beijing the manufacturer such as factory of the first machine tool approbates factory of factory of the first machine tool, instrument of Tsinghua university nicety, Qinghai, mix with planer-type milling machine of XA5750 ram milling machine, XA718 vertical milling machine, XA2412/2410 the form a complete set such as milling machine of numerical control of milling machine of different of milling machine of vertical of XKA5032 numerical control, numerical control screw, XKA8132/8140. Besides, also apply at composite material forming machine embryo of midday of car of instrument, steam a paragraph, shape 2 paragraphs reach cut of material of component of group control of wind tunnel of decide machinery, satellite, electron, make up the domain such as the belt. Current, nearly 200 application at home viviparity of midday of each big steam car produces a line, daily 24h moves continuously. Divide outside domestic application, begin from 1997, product of this company share by Beijing form a complete set of factory of the first machine tool exports the nation such as Germany, Canada, Australia. From 1994 up to now work off is covered near 1000 times hand in / dc servo, will a few years do not have a repair, according to this company record number looks, only 8 all bring about loop of insurance resistor, power source and interface as a result of user wiring mistake yuan parts of an apparatus is burned-out. The user of product of use Zhong Baolun changed bad to homebred servo dependability view. China in the unit such as place of electrician of company of company of numerical control of limited company of numerical control system, Mount Everest, spaceflight numerical control, Chinese Academy of Sciences passes project of executive country science and technology to tackle key problem, the servo that already can need to place of system of numerical control of oneself of form a complete set of manufactory of each machine tool, still apply at technical reformation of a few old equipment. Luoyang bearing institute is own main shaft of report of high speed of research and development, already applied at bearing grinder, printed circuit board mill, auger wait for a respect.