The servo technology of FANUC takes unit with wait

Introductive servo device is the main component of numerical control system. The development of servo technology builds the base that controlling the technology such as drive of academic, electric machinery and electric power electron. Go up century at the beginning of 50 time, the feed drive of machine tool of a NC uses world bed hydraulic pressure drive. The force that is more than electrical system place to arise as a result of the power that area of unit of hydraulic pressure system produces (it is about 20: 1) , and inertial low, reaction is sharp, the feed servo device because of this primary NC system uses hydraulic pressure actuating device mostly. The Japanese Fuji at that time connects company computer to control a ministry (develop later for FANUC company) learned bed from Masschusetts Institute of Technology after technology of a NC, with electro-hydraulic pulse electric machinery regards drive of feed of numerical control machine tool as the system. 70 time are prime, as a result of oil crisis, increase hydraulic pressure low to environmental pollution and systematic ponderosity, efficiency reason, development of American GETTYS company goes electric machinery of servo of dc big inertia, static moment of force of electric machinery of this kind of servo and starting moment of force is large, got applied on NC machine tool, performance is good. On the other hand, FANUC company was developing new low noise, big torque 1974 electro-hydraulic when pulse electric machinery, encountered technical difficulty. And electro-hydraulic pulse electric machinery is former it is to make market of system of FANUC numerical control is had lead the main reason that arrives high to be close to be the champion almost; The paddy leaf gentleman that holds the position of company president at that time thinks repeatedly, "I am technical personnel, also be operator at the same time. Regard a technology as personnel, I serve as electro-hydraulic the contriver of pulse electric machinery and feel proud, self-confident; But as operator, I must relapse ask oneself: Electro-hydraulic don't pulse electric machinery goes down so intactly continuously and have the crisis? Carry investigation, I believe firmly new electric machinery will replace electro-hydraulic pulse electric machinery. " made at once then " give up what one favours " decisive definitely choose: Deserted use old electro-hydraulic plan of drive of pulse electric machinery, turn at the same time and introduce electric machinery of servo of big inertia dc to make a technology from American GETTYS company, undertake commercialization instantly. From now on, be in the world's biggest CNC company, the system of open loop is replaced by the system of closed circuit; The drive system of hydraulic pressure is replaced by electric drive system. This thing, pass in NC industry all the time for a story pasted on with approval. After this, FANUC succeeds again the ground uses communication servo electric machinery on numerical control machine tool, roll out new actuating device ceaselessly next: If electric machinery, direct drive electric machinery is installed to wait inside linear electric machinery, high speed, improved the performance of numerical control machine tool, simplified the rigid structure of numerical control machine tool. Machine tool of 1 numerical control is main to the machine tool of demand numerical control of actuating device have two kinds of actuating device: Feed servo actuating device and main shaft actuating device. These two kinds of actuating device decided the function actor bad of numerical control machine tool greatly. Machine tool of 1) numerical control installs the requirement A of buy to feed servo.

Of the static state of device of demand demand servo of physical characteristic and trends fast fall small, stiffness is big. The stiffness of the stiffness of servo and component of machine tool machinery has same sense, be in namely outside perturbed force (cutting force, gravitational substandard force) below action, these force pass the corner position of the generation on electric machinery axis to change from working component. Represent the displacement below effect of rules of unit outside force with C: θ of △ of δ = / in T type, △ θ is measured for working component angular displacement, t is adscititious perturbed moment. Requirement δ is very small, it is even 0, namely after electrify, servo device is in closed circuit condition, ask any outside force do not make the working component of the machine tool produces displacement (in) of limit less than. The sharp movement of some axis or whirligig transfer from interpolation motion sometimes in treatment of numerical control machine tool, the axial servo tigidity that if wait for,works is bad, treatment precision is couldn't get likewise assure, this is apparent. Servo tigidity is with be opposite the response of perturbed moment comes normally comprehensive regulating system. B.

Ask this is machined in outline accordingly quickly, special the requirement when old to curvature treatment boy or girl friend undertakes high speed is machined is stricter. C.

Material of the asks this can make numerical control machine tool applies to all sorts of differring cutting tool of timing scope, treatment is qualitative; Suit to machine craft at what all sorts of differring. When the machine tool is machined, be in when working component suspend status, also namely although the speed of feed electric machinery is 0, but requirement servo electric machinery still has torsion, such ability " chain " working component; Accordingly, feed servo device still is in " servo " condition. From theoretic say, the timing scope of feed drive is infinity. Perhaps say, the timing scope of feed has been jumped over greatly more. For instance the limits of 15 systems speed of FANUC can be amounted to 1, 000, 000, 000:1. D.

Output the output torsion with the particular demand of torsion, the overload torsion with ask certain. The property with laden machinery of machine tool feed basically is the attrition force that overcomes working component and cutting obstruction, because this basically is " constant torsion " property. The requirement of machine tool of 2) numerical control to main shaft actuating device A.

The property of enough main shaft load that exports machine tool of power numerical control is approximate at " constant power " , become namely when the main shaft rotate speed of the machine tool is high, output torsion is lesser; When main shaft rotate speed is low, output torsion is big; Ask main shaft actuating device also wants to have namely " constant power " property. But when main shaft electric machinery the job is when rated power, rated rotate speed, according to the principle of general electric machinery, the wide range timing that has constant power falls impossibly for rated power in electric machinery. Accordingly, often need to increase in the mechanical part of main shaft one or archives of gearshift of second gear machinery, in order to raise the torsion of low speed, enlarge the timing scope of constant power; Perhaps reduce rated output power, enlarge scope of constant power timing. B.

Material of the asks to apply to all sorts of differring to assure numerical control machine tool cutting tool of timing scope, treatment is qualitative, suit to machine craft at what all sorts of differring, actuating device of requirement main shaft has certain timing limits. To the actuating device of main shaft, general and inferior requirement is 1:100, high demand is 1:1, 000 above. C.

The requirement of speed precision asks static difference is spent commonly be less than 5% , higher demand is be less than 1% . If fast had fallen big, the quality that machines can suffer an effect, for instance bright and clean degree bad. D.

Actuating device of fast requirement main shaft also is used on fixed position function sometimes, this asks it also has certain fast sex. The servo of development 1) feed of 2 drive electric machinery uses electric machinery: Arrive from dc machine alternating current machine, from rotate electric machinery arrives linear electric machinery to electromotor, the sine of included angle θ becomes scale between the size of the size that its output torsion T and B1 of intensity of excitation magnetic induction and B2 of intensity of armature magnetic induction and B1, B2. Namely: θ of Sin of × of T=k(B1 × B2) (2) among them K is coefficient of proportionality; Dc machine is as a result of the position of brush on geometrical center line, so θ =90 ° ; Control is accordingly simple, can output larger moment of force, received wide application. But dc machine brush wears away easily, need often changes, this causes difficulty to maintenance. Developed communication servo electric machinery again then. Because communicate ≠ of electric machinery θ 90 ° , to improve performance, it is OK to use servo of alternating current machine to control theory and digital signal processor to three-phase communication inductive electric machinery undertakes vector is controlled in order to get θ =90 ° ; To communicating the servo electric machinery of synchronism chance construction, also can use vector pilot method likewise, get θ =90 ° through controlling the method of magnetic field included angle; Because its character is OK,comparative with dc machine, accordingly, the electric machinery great majority that feed servo uses uses this kind of electric machinery. Use the primary level of electric servo technology, the control of the instruction is imitate control; Big, precision differs drift of method of this kind of control, because digital control can overcome afore-mentioned weakness, because this receives application increasingly. Current, the norms of A3000HVis of servo electric machinery with the biggest FANUC is as follows: 250kW of rated output power, most high-power 530kW, locked-rotor torsion 3000Nm, torsion of the biggest output is 5300Nm, top rotate speed is 2000r/min, current, also be the biggest servo electric machinery on the world. This kind of electric machinery basically applies in numerical control to note model machine and punch to go up, former, these machinery basically introduce hydraulic pressure drive. Graph the actuating device of standard of be enslaved to be enslaved to of NC machine tool that 1 linear electric machinery and tradition of electric machinery of direct drive servo are designed and makes and controller, make the precision of treatment and speed are restricted. Going up century 80 time end appeared linear servo electric machinery. It is comprised by two component, electromagnetism force is direct action at mobile component need not mechanical join, without pitch cycle error, precision relies on feedback system and classificationed bearing completely. By power supply of driver of servo of total number word, tigidity is tall, frequency has rung, can achieve high rate consequently. For instance the linear electric machinery of L17000C3/2is: The biggest thrust can amount to 17000N, successive thrust 3400N/4080N/6800N(parts corresponding nature is cold / air cooling / water-cooling) , speed can amount to 4m/s, acceleration 30g, resolution can be amounted to 0.

01µm, taller even. Linear electric machinery and rotate electric machinery photograph is compared, basically be like below a few characteristics: It is a structure simple, because linear electric machinery does not need to whirligig becomes the additional device of sharp movement, make consequently the structure of systematic itself simplifies greatly, weight and bulk decrease greatly; 2 it is fixed position precision tall, be in the place that needs sharp movement, linear electric machinery can realize straight drive, all sorts of fixed position errors that can eliminate intermediate link place to bring consequently, precision of reason fixed position is tall; 3 it is response rate fast, sensitivity is tall, can achieve the air that keeps certain from beginning to end between slide block and stator unoccupied place and do not contact, this removed the osculatory attrition obstruction between stator, slide block, the sensitivity that improved a system greatly consequently, fast sex and along with use a sex; 4 it is working on the safe side, life grows. Serve as electric machinery of low speed moment of force directly on numerical control machine tool rotate another development that workbench is servo technology. Traditional whirl workbench is to pass electric machinery of high speed servo to drive commonly fall fast gear, worm wheel, worm deputy undertake falling fast. Transmission chain length, noise is big, need maintenance. After the servo electric machinery that uses direct drive, because increased diameter of electric machinery rotor, use rare-earth metal to regard magnetic pole as material, because this can obtain big torsion. Undertake optimal design to magnetic circuit, the torsion with reducing low speed is pulsatile. Express 1 it is function of positive drive workbench and direct drive workbench is compared. Express function of 1 gear workbench and direct drive workbench to compare project gear workbench rate of direct drive workbench is low tall acceleration is low tall servo stiffness (for example, positional gain) general Gao Kang disturbs opposite wild phase precision of large to weak clamp torsion relatively small fixed position is tall (main decision is mixed at coder resolution fall fast machinery) tall (main decision is mixed at coder resolution, mechanical stiffness bearing stiffness) , of FANUC workbench inside specific norms of D3000/150is of electric machinery of the servo that fit pattern is as follows: Torsion of the biggest output can amount to 3000Nm, successive and rated torsion can amount to 1200Nm, the biggest rotate speed is 150r/min, appearance height is 160mm, external diameter is 565mm. Because electric machinery of 2) main shaft communicates frequency control of asynchronous electric machinery to realize the function of power of constant torsion, constant easily, do not have the charcoal of dc machine to brush again, because this is used very quickly,go up in the main shaft of numerical control machine tool. Rise along with what a move in chess or a movement in wushu charges machine tool rate, to simplify transmission catenary, use even " 0 drive " structure, appeared consequently electric main shaft. The main shaft the machine tool and main shaft electromotor are compositive together, although its rigid structure is very simple, but precision and dependability ask however very tall. Current, general inside speed of electric machinery of outfit main shaft achieves 12000 ～ 15000r /min; Electric machinery uses the structure of three-phase asynchronous electric machinery, use change of method of change pole logarithmic to classification gearshift. Recently, appear again the structure of synchronous electric machinery, use rare earth magnet, raise output torsion, design structure of optimal machine tool, still developed the main shaft electric machinery of power of wide range constant. This has two kinds of methods: Reduce the power of original electric machinery, enlarge scope of constant power timing; Use change extremely logarithm, achieve constant power. If express,adopt specification of electric machinery of FANUC main shaft 2. Limits of rated power of characteristic of model of norms of electric machinery of main shaft of watch 2 FANUC (KW) speed limits (R/min)(base fast - the biggest fast) applied Ai standard type 0.

55 ～ 454, 500 ～ 15, power of constant of wide range of Aip of 000 lathe, machining center 5.

5 ～ 224, 500 ～ 8, electric machinery of AiT of 000 lathe, machining center and machine tool main shaft are connected continuously 1.

5 ～ 225, 000 ～ 20, high accuracy of AiL of 000 lathe, machining center is connected continuously, oil is cold 3.

5 ～ 2215, 000 ～ 20, install inside AiB of 000 lathe, machining center 0.

55 ～ 501, 000 ～ 30, power supply of high pressure of AiH of 000 lathe, machining center 0.

55 ～ 1004, 000 ～ 20, 000 lathe, machining center the develops FANUC actuating device of 3 actuating device basically comprises by 3 parts: Power source, amplifier, control. Power source basically turns into communication to flow continuously, rise pump to voltage sends wire back the net or try to handle, undertake protective waiting for a function when power source breakdown. The brilliant brake of inchoate development is in charge of servo control is simple, speed limits can satisfy the need of machine tool of ordinary numerical control, because brilliant brake canal is rated electric current is big, short time passes voltaic ability strong, because this is opposite,electric machinery of servo of big inertia dc can have developed the characteristic that adds decelerate bear, high speed, high. Control is used commonly move photograph pilot method. The frequency that the defect that brilliant brake is in charge of servo is power changeover is inferior, the frequency 50Hz that can be electrified wire netting only perhaps is as high as 300Hz. Accordingly, electric current of low speed of its servo device is fluctuant scope of bigger, timing is not big, fast answer slow. As a result of afore-mentioned reasons, from the technology FANUC rolled out modulation of PWM(pulse width again) pilot circuit. For instance, with V0 of fixed voltage of frequency modulation direct current source, when square wave when occupying the empty T/T0 that compare △ to change, output average voltage V1 to be: V1=[△ T/T0]V0 (3) like that the weaveform of this kind of voltage also is pulsatile, but can achieve as a result of the frequency of modulation very tall, because this weaveform is OK still very good. See from afore-mentioned principles, the characteristic of PWM can make fast sex of the system is carried very high. If use transistor, its trends adjusts time is faster than silicon controlled rectifier, but permission electric current is lesser, because this suits the drive circuit of medium, small-power quite. Besides dc feed electric machinery, the alternating current machine of FANUC also uses PWM to control. Communicate the control of electric machinery, it is to pass the principle of communication, dc, communication to produce alternating voltage to control alternating current machine. Above all the alternating voltage of electrified wire netting becomes volts d.c. through rectification, power supply gives inverter, it dc magnetic circuit, reduce low speed pulsatile. This kind of electric machinery suits the application of numerical control lathe and machine tool of numerical control gear very much. Divide this beyond, FANUC still developed the main shaft electric machinery that connects continuously with machine tool main shaft, electric machinery of oily cold main shaft. Become communication to simplify; And inverter is by PWM pilot, pass PWM circuit, the amplitude of metabolic alternating voltage, when frequency is low, the amplitude that outputs voltage is low also, when frequency is tall, because use the control of PWM, the amplitude that outputs voltage is tall also. Achieve frequency conversion so while also changed voltage. Not only feed drive system uses this principle; And the timing that communicates main shaft electric machinery also is such. General frequency is 3kHz ～ 10kHz. The development of the development of servo technology and technology of electric power electron is concerned, on the power electronic parts that the century uses at the beginning of 50 time is valve, thyratron, bulk big, life weak point, efficiency is low; After 60 time, appeared in succession again commutator of silicon controlled rectifier of SCR(of brilliant brake canal) , IPM of module of power of IGBT of dynatron of bar of MOSFET of canal of effect of field of power transistor GTR, power, insulation, intelligence. Magnify power, spark circuit of control, drive, protection is compositive together. The occurrence of these parts of an apparatus, the control performance that improved a system greatly and compositive degree, dependability, narrowed thereby dimension, reduced cost. The development FANUC of 4 control technology packs the function of the function of buy and system of implementation numerical control to raise servo, undertake improvement ceaselessly to controlling a technology. Among them the mainest control function is controlled for HRV. If pursue,2 are shown. The CNC of FANUC uses communication servo electric machinery, the electric current that has shed winding actually is alternating current. This has 2 kinds of methods to be able to undertake controlling: (Operating ring of 1) electric current and control are AC quantity; (2) alternates through coordinate voltaic variable undertakes controlling for DC quantity. Use latter to undertake controlling commonly now. Also call vector commutation control. Vector controls a principle to be: In alternating current machine, rotor produces magnetic field by the electric current of stator winding induction; And stator electric current contains two component, one affects excitation magnetic field, another influence electric machinery outputs torsion. Component of these two electric current is together in stator coupling, need speed to need torsion pilot situation again already to make communicate electric machinery application to be in, must control the Ou of voltaic component solution that affects torsion, use magnetic flux vector to control a law to be able to depart these two component, undertake becoming independent controlling. HRV is based on latter control namely. Because use DC control, its control character does not depend on the speed of electric machinery (namely frequency) of electric current, set out from speed pilot viewpoint, this means the speed of the actual torsion that decides by torsion instruction and electric machinery to have nothing to do. Although low-cost, structure is simple,communicate asynchronous electric machinery, inchoate because power electronic parts is cumbersome, backward, control academic stale, control performance is poor, so a long time does not have alternating current machine to get applied on NC system. As the development of technology of electric power electron, 1971, the Blaschke of German Xi Menzi invented the magnetic flux vector that communicates asynchronous machine to control a standard; 1980, the studies the group is using microprocessor vector pilot that German Leonhard heads gains headway in research, make vector control economic change. Go up century 70 time end, electric machinery of asynchronous of phase-in of NC machine tool gives priority to drive electric machinery of the axis. To system of contemporary numerical control, the biggest breakthrough that servo technology obtains is OK end is: Communication drive replaces control of dc drive, number to replace imitate to control (perhaps call it software control replaces hardware to control) . The result of these two kinds of breakthroughs arose to communicate digital drive system, especially the application of DSP of digital signal processor, computational rate of the system rises greatly, sampling time decreases greatly. Make servo performance improvement, dependability rises, debug convenient, flexible increase. Promoted the development of processing technique of high speed of high spirit of numerical control machine tool consequently. HRV of block diagram of control of graph 2 HRV is " tall answer vector " (the meaning of High Respons Vector) . Alleged HRV control is control of pair of vector of alternating current machine undertake optimizing from hardware and software side, what take unit in order to realize wait is high-powered change, make the treatment of numerical control machine tool achieves high speed and high spirit thereby; To implement high speed and high spirit, the HRV of feed servo device basically controls: (1) has high spirit high-speed to answer to inputting an instruction; Reduce sampling time, undertake to electric current high accuracy detects; Optimize software design, undertake controlling to electric current and speed, in order to increase speed gain and positional gain, improve the performance that improves a system thereby; (2) is right external interference has good rash club sex; (3) uses high accuracy coder; (4) installs HRV filter, reduce mechanical and syntonic effect. Can make through above measure speed gain of the system is achieved 5000% , positional gain reachs 300/ second. And the HRV of device of main shaft servo basically controls: (1) installs HRV filter, reduce mechanical and syntonic effect, increase speed gain; Increase systematic stability; (2) essence attune adds decelerate, raise synchronous sex; (3) reduces temperature rise of the winding when high speed. The 5 self-regulated humorous technologies that use digital servo, go to the lavatory to be debugged to make an user convenient at debugging, to servo device, FANUC still was designed " Servo Guide " software tool. It uses self-regulated come to an agreement (Self Tuning) technology can undertake servo parameter automatically through the computer set, show locomotive weaveform, make servo convenient, accurate, apace is debugged and undertake maintaining. CNC Milling