Curved surface of functional tooth profile exhibits technology of numerical control of accurate closed circuit to consider

  • Time:
  • Click:26
  • source:PURELIFE CNC Machining
Summary: Be based on technology of lock interblend frequency, put forward to be used at the machine tool " inside connection " technology of a kind of when transmission catenary error measures data processing new-style fractionize and new-style plan of synchro control of interpolation of hardware of 0 errors double closed circuit. The chain of drive of axis of report of numerical control of complete closed circuit that developed curved surface of functional tooth profile to exhibit movement and synchro control system, the numerical control that is used successfully at Y38A gear-hobbing machine is changed transform. The measurement of transmission catenary precision machines precision test to make clear with curved surface of real function tooth profile as a result: This new-style fractionize technology and principle of synchro control of interpolation of hardware of 0 errors double closed circuit are correct, the curved surface of functional street outline of development achieves number of athletic closed circuit to carry a system to have but speed of operation, interpolation fast, precision sex of tall, real time is good wait for a characteristic. The high accuracy that 1 foreword curved surface achieves is based on high accuracy of pilot of motion of its surface figuration, the key that the rolling cut of high accuracy of curved surface of functional tooth profile that is used extensively at realizing motion and motivation to deliver machines is the precision that should raise its to exhibit movement, and metrical high accuracy is to realize high accuracy to make with pilot foundation. For this, the author studies a machine tool according to coming for years " inside connection " catenary precision measures transmission to carry further analytic research with pilot experience, offerred technology of a kind of new-style hardware fractionize that is based on contemporary and compositive parts of an apparatus, use at machine the Song Dynasty ' inside connection " transmission catenary error measures data processing, the chain of drive of axis of report of numerical control of high accuracy closed circuit that developed curved surface of functional tooth profile to start campaign; The program of principle of synchro control of interpolation of 0 errors double closed circuit that offerred implementation of a kind of new-style complete hardware, use at axis of report of tooth profile curved surface to extend athletic drive cable length two extreme athletic synchro control. Meanwhile, still developed corresponding hardware system, the numerical control that uses at Y38A gear-hobbing machine is changed transform. Principle of technology of 2 new-style fractionize 2.

1 fractionize multiple and resolution are commonly used linear or angle displacement quantity detects infect feeling cell synchronized of the rule of main and glazed bar, feet that hold bar, magnetism feet, induction. Because inductive synchronized has interference rejection capacity strong, have an error average effect, installation and safeguard convenient wait for a lot of advantage, because this receives wide application in actual production. It is those who raise afore-mentioned modulation sensor to measure resolution, satisfy the requirement that nicety and high accuracy measure, must make fractionize processing to their output signal. If make its,frequency of signal carrier wave is a day, frequency of computer clock pulse is a day, use direct fractionize technology, criterion its fractionize multiple is: D=fefc(1) measures resolution to be P= τ D(2)2.

2 " FM-FD-FM " type of new-style fractionize primary reason (1) , type (2) can see, rise further measure resolution to have two ways: Increase frequency of computer clock pulse Fc or reduce Fe of frequency of signal carrier wave. But as a result of Fc raise the restriction that accepts frequency of electronic parts job (at present but the frequency of the biggest computation of process designing tally is 10MHz) , and Fe cannot be chosen too lowly again commonly, otherwise sensor signal is weaker, interference rejection ability is poorer, easily unbalanced and lack fidelity, because of Fe(of frequency of excitation of signal of this induction synchronized namely carrier wave frequency) choose between 2 ~ 20kHz commonly (take 10kHz) normally. According to above circumstance, very hard simple land measures resolution with raising Fc or the kind that reduce Fe to rise. Offer a kind of new-style fractionize technology for this author: Already collect signal of type of high frequency modulation undertakes the sensor of significant information mixing processing, reprint the significant information such as displacement, error to a frequency again undertake to its times frequency of N is handled on the another frequency signal with low Fe of frequency of more primary carrier wave, undertake mixing is handled 2 times again next, with complete demodulation. Be opposite again right now the displacement after times frequency of N or error signal undertake fractionize of fill of personal computer clock, can achieve raise resolution and the goal that measure precision, implementation high accuracy is measured. The block diagram of hardware implementation principle of afore-mentioned methods sees a picture 1. Your the output signal frequency of phasic modulation sensor is Fi=fe+fc(3) type in: Fe -- Fv of carrier wave frequency -- displacement signal frequency generates a referenced frequency signal with close of carrier frequency Fe by signal generation circuit Fr1(fr1<fe) . Signal closes the classics and Fr1 mixing, low wave that connect filter to be handled so that signal F1f1=(fe-fr1)+fv(4) makes lock appearance to F1 times frequency is handled (in order to increase the stability) of low frequency signal, signal F2f2=N[(fe-fr1)+fv](5) type is medium: N -- times frequency coefficient, can undertake by personal computer according to frequency of signal of the displacement that be measured alterable beforehand buy again F2 and mixing of referenced signal Fr2=N(fe-fr1) and handle via the low wave that connect filter, can get the Foutfout=Nfv(6) of stable question mark of significant information handles afore-mentioned fractionize the technology to call containing displacement only directly ' mixing - times frequency - mixing " fractionize technology, brief write down " FM-FD-FM (Frequency Mixing-Frequency Doubling-Frequency Mixing) " fractionize technology. Measure precision to make as far as possible tall, fr1 of excitation frequency Fe, referenced frequency, Fr2 all arises by scale down of same and accurate clock. Song Xianchun and Li Chunyang are published at " production technology and machine tool " 1994 the 11st period " testing system of personal computer of synchronized of induction of poor frequency type and application " in used circuit of one class mixing to rise merely measure resolution, but when obtaining absolutely displacement to measure information, still need to undertake many processing to data of sampling of personal computer fractionize, from measure those who take is phasic in depart drops signal of low frequency carrier wave (Fe-fr) , ability obtains the phasic information that measures on behalf of mechanical displacement. The number that the measure that adopts normally is software implementation is restricted wave filter. But this kind of method exists already in handling a process principle error, need many operation time again, cause real time sex poorer, measured precision to also call a discount at the same time. The article adopts complete hardware " FM-FD-FM " processing, can get displacement directly significant information, the real time sex that rose to measure greatly thereby and measure precision. Be like to inductive synchronized, if take clock frequency Fc=10MHz, excitation frequency Fe=10kHz, if use measurement technique of common and direct fractionize, d=1000 of its fractionize multiple, measure resolution P1=3.

6 horn second () of round induction synchronized, ) of synchronized of P2=2µm(sharp reaction; And use new-style mixing fractionize to measure a way, take referenced frequency Fr=9.

85kHz, criterion fractionize multiple D=67667, measure resolution P1=0.

05 horn second (angular displacement) , displacement of the lines can amount to P2=0.

03µm, commonner fractionize measures resolution the law raised nearly 68 times. Principle of synchro control of interpolation of hardware of double closed circuit of 3 0 errors 3.

Analysis of method of interpolation of 1 traditional software is current, on numerical control machine tool, because be opposite,pulse interpolation allocates much axis linkage and synchronous motion pilot to use software to come true normally, because this people pays attention to model of algorithmic to all sorts of software interpolation, data processing and program to wait more,undertake study, and the plan research that comes true to hardware is very few however. However, to software pilot motion of two axes synchronism controls a system, it is the positional signal according to drive shaft commonly, after classics software is calculated, give out athletic arteries and veins to develop control to follow the campaign that uses a rod by software, coordinate synchronism what make with the motion of drive shaft. Use algorithm of this kind of control, when concerning for integer between two pulse, control is relatively convenient and control precision is taller. But fall in most circumstance, concern to be not integer between two pulse, because this carries section normally,control is added decrease a certain quantity of pulse is enumerated method will realize treatment to control. This kind of processing on one hand real time sex is poor, have in machining a process along with the mutation that uses rate, cause the impact between the cutting tool that be mixed by treatment workpiece thereby, the service life that causes treatment quality and cutting tool is reduced. Besides, use this kind of method to return existence interpolation to control error of data processing of principle sum of errors, cause control precision is inferior. Yoram Koren and Rong-shine Lin are published in " Annals Of CIRP " 1995 the 4th period go up " Five-axis Surface Interpolator " the new-style controller that gave out to be based on pure hardware one kind, have a lot of advantage quite with afore-mentioned software interpolation methods. Of the principle of interpolation of synchro control speed of although two time are invariable alternant counting method put forward, gave out a kind of attempt, can accomplish eliminate accumulate an error, but the local error that because different time constant causes alternately,still exists. No matter how be improved,this is meant, the control law that relies on software interpolation implementation is put in principle error commonly, sex of its real time also grows because of software executive time (be compared with hardware and character) and poorer. In addition, because resolution of signal of encode sensor pulse is finite,also will bring about very low control precision. 3.

The figuration movement that motion of synchronism of interpolation of 0 errors hardware controls 2 pairs of closed circuit to the principle is expressed according to functional tooth profile and extend a law makes further analysis and research, combinative gear-hobbing machine realizes the characteristic that its surface figuration moves, be based on technology of Suo Xianghuan road, the author puts forward a kind of double closed circuit motion of synchronism of interpolation of 0 errors hardware dominates program, its principle. Control program basically differentiates ④ of the ~ that it is ① 4 component: "① " it is electric machinery (the closed-loop control loop of M1) speed. The purpose of this loop is the stability that assures electric machinery speed, electric machinery of emery wheel of worm of directive of actual measurement result (M1) rate stability can be achieved 0.

2% . "② " it is circuit of firm frequency of implementation frequency changeover and lock photograph. The relation between frequency is FG=nfTm(7) type in: FT -- the working frequency FG of cutter shaft -- the working frequency M of workpiece axis, n -- scale down coefficient " ③ " the circuit of closed circuit follow-up control that is M2 of implementation electric machinery. The input of pulse signal feedback of coder of electric machinery axis comes EODA servo driver, after with classics 89C51 commutation of frequency of athletic control plate is handled advocate accuse signal to undertake comparative, make the closed circuit follow-up control of speed of workpiece servo electric machinery, the link error of drive of logarithm word servo and electric machinery itself undertakes compensating. "④ " it is to point to batch of code dish interface circuit part. Its action is to come true to be machined what tine teeth of a cogwheel counts beforehand buy input. Athletic control plate passes 89C51 synchronism read in sheet / status of double head treatment and beforehand of buy be counted to decide initialization by treatment tine teeth of a cogwheel 8254 but scale down of process designing computation implement 1/n of medium scale down coefficient and 1/m. BCD code dial and 89C51 join are used pick a way, in order to save I/O line number. Number of head of your worm emery wheel ages for K, workpiece number is NG=2000 of resolution of coder of axis of NT=2500 of resolution of coder of ZG, cutter shaft, workpiece, criterion NT/nG=ZG/ZT can get FT=ZGNG=4ZGfGKNT5K(8) couplet vertical (7) , type (8) , the concern that the scale down coefficient that gets interpolation controls frequency of FG of signal of input signal FT and output to concern deciding hardware is synchronous athletic should satisfy takes form commonly for N=4ZGm5K(9) (the K=1 in 9) or 2, take ZG=17 ~ the integer of 120, because M of coefficient of this scale down, N all finds integer easily. Use interpolation of this kind of hardware to control a method to undertake frequency alternates apparently, nonexistent interpolation operation controls an error. Used closed-loop control respectively again in end of two electric machinery at the same time, make a lock synchronous dog phasic lag error is very small, and the servo that follow-up closed circuit system compensated workpiece electric machinery again controls an error. Adopt afore-mentioned measure, can make cutting tool and workpiece motion achieve very tall synchronous and harmonious precision. Block diagram of principle of control of position of servo of number of axis of report of 4 accurate closed circuit uses afore-mentioned new-style fractionize technologies and double closed circuit the sheet that athletic control principle developed 0 errors synchronism to be based on standard of PC bus line piece machine measure, compose built rolling cut of face of functional tooth profile to extend cable length of drive of axis of report of athletic pilot complete closed circuit. Use control plate of motion of four-axle of AT6400 of American Parker company, developed the system of gear hobbing of open mode numerical control that is based on IPC, change at numerical control of Y38A gear-hobbing machine into function transform. Drive of servo of word of number of axle of report of gear-hobbing machine closed circuit controls systematic principle. Among them FV and FG meaning are Alexandrine satisfy type respectively (6) and type (8) . 5 accurate closed circuit extend athletic drive cable length assessment of synchro control precision becomes athletic drive chain to exhibiting synchro control precision can move error size to measure with telex. Alleged telex uses an error is the two executive extreme that point to to rigorous motion concern is had to ask on the machine tool when the motion between controls implementation by system of computerized numerical control, actually border drive compares the deviation that compares at academic drive relatively; To some extreme, it is to show border movement position is actually relative the deviation at good exercise position. The definition of the meaning that telex changes an error and mechanical transmission error is same, the kind that just is its motion implementation is different. The telex that CNC gear-hobbing machine extends athletic drive cable length moves an error to point to two extreme namely -- workpiece (workbench) with cutting tool (hob) the athletic error between. This error can press undermentioned formula to calculate: In type of G of θ of I- of × of T of θ of Δ θ = : I -- academic drive compares θ T -- cutting tool is actual displacement θ G -- work is real displacement measures the volume that to extending athletic drive cable length the telex when synchro control changes an error through the following test. Test condition: Rotate speed of only head hob all is 47.

5r/min, be aged by treatment teeth of a cogwheel counts Z=100, carry for nothing boil cut; Those who measure a system to use own development is odd feedback measures a machine and synchronous motion controls functional board. The test result that the CNC below circumstance of the stable state when Z=100 exhibits athletic telex to use an error (by hob every turn to workbench) of 512 bits of sampling. Apparent, telex of CNC of closed circuit of the Y38A below stable state gear-hobbing machine uses an error general <10 ~ 14Arcsec. The paper of doctor of Shandong industry university this second test result and Zhang Chengrui " error of catenary of machine tool drive builds model and compensation control research in real time " in the error of catenary of pure mechanical drive to Y38A gear-hobbing machine measures an outcome 20Arcsec undertakes 17 ~ more knowable: Telex uses an error more mechanical transmission error reduces about 3 ~ 10Arcsec and error wanting accumulates a phenomenon. This specification used system of closed circuit CNC to eliminate the source of error with main gear-hobbing machine -- the bigger chief periodic error that worm wheel causes. Because the crucial part of gear cutting precision is affected on gear-hobbing machine,be worm wheel deputy, the discretion of worm wheel production precision is deciding the treatment function of gear-hobbing machine directly. And the production difficulty of high accuracy worm wheel is great, production cost is very high. Grow the elimination of periodic error, mirror on precision, can make be accumulated by red-letter day of treatment gear week the error reduce, raise precision of gear teeth directional, make thereby the gear that can gain high accuracy with the worm wheel treatment of low precision, reduce the production cost of gear-hobbing machine greatly, because this has far-reaching sense. The new-style fractionize technology that the test proved to put forward as a result " FM-FD-FM " the validity of the principle and feasibility. Error of electric transmission short period is more original increase somewhat. It is facilitating observation, take workpiece to had turned from inside sampling dot the measurement when 40 tine angle undertakes an analysis as a result. Space of every upend empty lies between its cross axle to be nodded for 10 sampling, workpiece has turned to make an appointment with the angle of a tine. Apparent, error of the motion between its sheet tine is 4.

5 ~ 10Arcsec. Report of short period error arrives to be machined on gear, will make teeth shape error more original increase somewhat, this basically is the wave motion as a result of hob speed and high frequency and oscillatory influence, cause system of electric axis transmission to dog quickly answer function to differ place to cause. Believe as hob advocate of athletic control means and the change that control algorithm and rate stability rise, workpiece follows the function of the system of electric axis transmission that hob moves will get ameliorative, telex moves an error to be sure to decrease further. It is feasible that the sport of synchronism of interpolation of hardware of axis of closed circuit report that raise controls a system, it can be used at on the machine tool two extreme to carry out an all situations that have concern of rigorous harmonious motion. 6 conclusion are based on lock interblend frequency and times frequency technology, developed fractionize of signal of a kind of modulation sensor to handle new technology, call " FM-FD-FM " fractionize law. Be based on technology of lock photograph scale down, put forward a kind of double closed circuit plan of principle of system of control of sport of synchronism of interpolation of 0 errors hardware. Be based on afore-mentioned technical principles, the system of catenary of drive of axis of report of numerical control of high accuracy closed circuit that developed curved surface of functional tooth profile to machine implementation to exhibit movement. The experiment proved the validity of new-style principle and feasibility. Athletic control system and its technology can use the synchronism of interpolation of electric axis hardware of development at on the machine tool two extreme to carry out everything what have concern of rigorous harmonious motion " inside connection drive " circumstance. CNC Milling