CN100447694C - Control system of large stroke nanometer precision location - Google Patents

Abstract

The present invention relates to a positioning control system used in high precision measurement or experiments, the aims of which are to overcome the defects in the prior art, and offer a positioning control system which can recover in time to monitor the changes of positions of measuring or experimental instruments. The present invention comprises a light source, two semi-reflecting and semi-transparent mirrors, an interferometer, a half-wave plate, a quarter-wave plate, an analyzer and an analysis control system, wherein light paths generated from the light source are divided into two beams of light after the light paths are emitted to the first semi-reflecting and semi-transparent mirror, and the two beams of light are respectively emitted to two arms of the interferometer; a beam of light is formed by that the light which passes through the arms is joint with the light which passes through the arms after the light passes through the half-wave plate; the beam of light is emitted to a light sensing device of the analysis control system after the light passes through the quarter-wave plate to realize high precision position with large stroke. One of the arms of the interferometer is installed on a step motor with multistage precision, the minimum stroke precision of the step motor is nanometer, a control end analyses and controls the connection of the system.

Description

A kind of control system of large stroke nanometer precision location

Technical field

The present invention relates to the positioning control system of use in high-acruracy survey or experiment, a kind of control system that can carry out the nano-precision location of saying so more specifically.

Technical background

In high-precision measurement or experimental system, often the stability to total system has very high requirement, and the position between instrument relation particularly even small interference exists, also can cause measuring or experimental result completely different.So, in high-precision measurement or experimental system, to measure or the environmental requirement of experiment very high, generally be in the environment of high degree of isolation, to carry out, as Superclean Lab etc.Even but in the environment of high degree of isolation, owing to moving of personnel, the running of instrument, or even flowing of air all exists interference to measuring or testing.And the construction cost of the vacuum experiment chamber of ultra-clean is very high, and difficult in maintenance.Thus, also occurred monitoring location system miscellaneous in the prior art, be used for the position relation between tracking measurement or the experiment instrument, in case the instrument relative position changes, monitoring location system can restore the system to initial position timely, plays the effect of real-time monitoring.But because the interference that generally is present in high-precision measurement or the experimental system is very faint, so how can measure so faint interference, timely feedback information and faint undesired signal is amplified to can moving system returns to the important indicator that initial position is the outstanding monitoring location system of performance.Existing monitoring location system all can't satisfy these indexs fully, can only remedy its defective by mathematical method, and can't be competent at especially in realizing the big hi-Fix that disturbs.

Summary of the invention

The objective of the invention is to overcome deficiency of the prior art, provide a kind of can control measurement or experimental apparatus between the position relationship change, and the positioning control system of in time recovering, particularly a kind of positioning control system that can realize the large stroke and high precision location.

The present invention is achieved through the following technical solutions its goal of the invention.

The present invention has designed a kind of control system of large stroke nanometer precision location, adopt the mode of photoinduction to carry out the system location, comprise light source, two half-reflecting half mirrors, interferometer, a half-wave plate, a quarter-wave plate, an analyzer, the analysis and Control system, light path is divided into two-beam after light source incides first half-reflecting half mirror, incide two arms of interferometer respectively, light by the first arm merges into a branch of light with light by second arm at second half-reflecting half mirror after by half-wave plate, by injecting the optical inductor of analysis and Control system after quarter-wave plate and the analyzer, for realizing the hi-Fix of big stroke, the present invention is installed on one of them arm of interferometer on the stepper motor of multi-stage accuracy, the minimum stroke precision of stepper motor is a nanoscale, and control end analysis and Control system connects.The interferometer that the present invention adopts is a Michelson interferometer, monitor change in location between two arms by monitoring light by the phasic difference of the caused two bundle circularly polarized lights of two arms of Michelson interferometer, and the stepper motor by multi-stage accuracy moves one of them arm and follows the tracks of another arm, to reach the purpose of invariant position between control two arms.The present invention adopts the stepper motor of multi-stage accuracy to realize the High Accuracy Control of big stroke, the stepper motor of general multi-stage accuracy is made of a little stroke stepper motor and a big stroke stepper motor, and little stroke stepper motor is connected with the analysis and Control system respectively with big stroke Stepping Motor Control end.When required stroke reaches the range of little stroke stepper motor, can move big stroke motor replenishes, regulate particular location by little stroke stepper motor again, the stroke accuracy of big thus stroke stepper motor can not be greater than 2 times of little stroke stepper motor range.Want to adjust in the accuracy rating of nanometer the length of an arm of Michelson interferometer, and response speed wants also to reach a millisecond magnitude, reach so little stroke stepper motor that requires and just be merely able to adopting piezoelectric micromotor stroke device.

Be to realize the control to total system, analysis and Control of the present invention system comprises: be used to the feedback module surveying weak one and convert thereof into digital signal corresponding; Be used to adjust the execution module of interferometer arm position; With the control module that is used for control of realization center and data transmission; Control module is connected with execution module with feedback module respectively.Feedback module comprises: be used for the optical diode amplification filtering part that light intensity signal extracts and amplifies; The V/F conversion portion that the back voltage transitions becomes frequency will be amplified; With the order that responsible processing and control module transmits, control first and second digital regulation resistances, and become numeral to pass to the control and the tcp data segment of control module frequency inverted.

In order the faint optical signal that detects to be amplified and converts thereof into digital signal corresponding, the amplifying circuit of optical diode amplification filtering of the present invention part comprises the electric current scale-up version amplifying circuit of being made up of with first amplifier optical diode, digital zero setting circuit of being made up of first digital regulation resistance and impact damper and the totalizer of being made up of second digital regulation resistance and second amplifier that reverse enlarging function is arranged; The filtering circuit of optical diode amplification filtering part adopts bivalent high-pass filter.

Promotion piezoelectric micromotor stroke device moves and response speed is also wanted to reach a millisecond magnitude in order to reach, execution module must comprise uses the DA converter, be responsible for microcontroller, high voltage expanded circuit three parts that are used to amplify the DA converter output voltage with communication between the control module and control DA converter.

The advantage of serving as control module with computing machine is clearly, can realize various algorithms, friendly interface very like a cork, is easy to debug, data can be stored, also have other a large amount of data processing softwares available simultaneously.Computing machine of the present invention adopts the PID control method to control the operation of little stroke stepper motor and big stroke stepper motor in real time.Pid control law is the electronic control method that a kind of quilt adopts for a long time, and this method exists lot of advantages: it is that technology is the most ripe in the continuous system, and a kind of method that is most widely used.Its structure is flexible, not only can regulate with conventional PID, and can adopt the mutation of various PID according to the requirement of system, as PI, PD control, incomplete differential control, integral-separated PID control, the PID control in band dead band, speed change integral PID control, ratio PID control or the like.In the PID control system, systematic parameter is adjusted conveniently, and effect is relatively good in most of industrial processes.Powerful, be a kind of control method that can be applied to relatively fuzzyyer object.Up to the present, still have many industrial objects to can not get or be difficult to obtaining precise math model, therefore, use relatively difficulty even not possible of Direct Digital control method, at this moment just can only seek help from pid algorithm.Simple and practical, the use of pid control law is adjusted its each parameter the most keyly exactly, and adjustment process is the process of an experience accumulation, now can be on top of the scope of each parameter.The control effect is relatively good, though computer control is dispersed, it is similar to continuous variation for the bigger system of time constant.Therefore, analog regulator can be replaced fully, and satisfied effect can be obtained with digital PID.

The present invention can be applied in various measurements and the experimental system, controls the relative position between two instruments, has following outstanding substantial effect and obvious improvement with respect to prior art the present invention:

1. adopt the principle of the interference of light to come the Design Orientation control system, can sense the subtle change of system, highly sensitive;

2. can realize the nano-precision location of big stroke, guarantee stable between can the holding position under the general interference of measurement or experimental system;

3. can amplification detection arrive enough intensity, and the stepper motor response speed is wanted also to reach a millisecond magnitude to faint undesired signal;

4. serve as control module with computing machine, the running of control system flexibly, and processing speed is rapid;

5. adopt pid control law to can be good at realizing control to nonlinear controlling object, therefore can control survey or experimental system in various external interference;

6. one-piece construction is simple, and it is convenient to use, and greatly reduces the construction cost of measurement or experimental situation.

Description of drawings

Fig. 1 is the index path of system of the present invention;

Fig. 2 is a control flow chart of the present invention;

Fig. 3 is the system module figure of analysis and Control of the present invention system;

Fig. 4 is the control system block diagram of Fig. 3;

Fig. 5 is the circuit diagram of the amplifying circuit of optical diode amplification filtering part;

Fig. 6 is the circuit diagram of the filtering circuit of optical diode amplification filtering part;

Fig. 7 is the circuit diagram of V/F conversion portion;

Fig. 8 is the circuit diagram of high voltage expanded circuit;

Fig. 9 is for adopting experimental system of the present invention at the change curve of time inducing current that is hit.

Embodiment

The present invention is described further below in conjunction with accompanying drawing.

The invention provides a kind of stable control system of large stroke nanometer precision location of supervisory system that is used for, native system is to adopt light intensity to reflect the control method of optical path difference information, and the index path of this method as shown in Figure 1.He-Ne LASER Light Source 1 with a horizontal polarization, can add a polarizer and obtain linearly polarized light, be divided into two-beam a, b after inciding first half-reflecting half mirror 2 from the left side, incide two arms 91,92 of Michelson interferometer respectively, in light path, increase a half-wave plate 4 and a quarter-wave plate 5, as shown in the figure, will become a left circularly polarized light and a right-circularly polarized light at two-beam respectively through behind the quarter-wave plate 5 so, inject the optical inductor 7 of analysis and Control system 8, these two circularly polarized lights can be become with vector representation respectively:

${\stackrel{\→}{E}}_1\left(t\right)={\stackrel{\→}{E}}_{1x}\left(t\right)+{\stackrel{\→}{E}}_{1y}\left(t\right)=E_1\stackrel{\→}{x}\cos \mathrm{\ωt}+E_1\stackrel{\→}{y}\sin \mathrm{\ωt}---(1-1)$

${\stackrel{\→}{E}}_2\left(t\right)={\stackrel{\→}{E}}_{2x}\left(t\right)+{\stackrel{\→}{E}}_{2y}\left(t\right)=E_2\stackrel{\→}{x}\sin (\mathrm{\ωt}+\mathrm{\δ})+E_2\stackrel{\→}{y}\cos (\mathrm{\ωt}+\mathrm{\δ})---(1-2)$

Wherein δ is that the δ value is by the position control of interferometer moveable arm 91 by the optical path difference of two arms, 91, the 92 caused two bundle circularly polarized lights of Michelson interferometer.After these two circularly polarized light stacks, the x direction of its resultant vector and the component of y direction can be write as:

E _x＝E ₁cosωt+E ₂sin(ωt+δ) (1-3)

E _y＝E ₁sinωt+E ₂cos(ωt+δ) (1-4)

By an analyzer 6, its angle that shakes direction and x direction thoroughly is again Then two projections of component on the direction of shaking thoroughly can be write as:

(1-5) formula and (1-6) formula just can obtain electric field intensity by vector addition by light wave behind the analyzer:

So the light intensity that optical inductor 7 can receive is:

Since optical inductor 7 actual reception to be signal to time integral, (1-8) formula to time integral, is considered that all Xiang Douwei that contain ω t are zero, and δ is changed into-δ that the signal list that detector receives is shown as:

We obtain them and close to be at last:

From relational expression (1-9) as can be seen, the light intensity I that optical inductor 7 detections obtain is made up of two parts, and first is a DC voltage.The second portion of intensity I is the optical path difference δ of 91,92 on two arms of together michelson interferometer and the angle of orientation of last analyzer

A relevant cosine function square.Suppose that analyzer is to keep static, so just can think that I is just only relevant with optical path difference δ.Because extraneous interference makes optical path difference be difficult to jump out some monotony intervals in the variation of moment, increase the interval or subtract the interval so only consider that cosine function is some, just can judge the variation of optical path difference according to the variation of light intensity I.

As shown in Figure 1, the arm 91 of interferometer of the present invention is installed on the stepper motor of multi-stage accuracy, the stepper motor of multi-stage accuracy is made of a little stroke stepper motor 10 and a big stroke stepper motor 11, the stroke accuracy of big stroke stepper motor 11 is not more than 2 times of little stroke stepper motor 10 ranges, and little stroke stepper motor 10 is connected with analysis and Control system 8 respectively with the control end of big stroke stepper motor 11.Come supervisory system by control method as shown in Figure 2, allow the change in location that arm 91 can real-time follow-up arm 92, keep the stable of system.After starting this positioning control system, the lock-out state that first initialization system is required enters real-time monitoring then, whether changes the position relationship change of monitoring between arm 91 and 92 by judging light intensity I.If finding light intensity I changes, so just adjusting little stroke stepper motor 10 makes it recover lock-out state, if the scope of adjusting has exceeded the range of little stroke stepper motor 10, then adjusting big stroke stepper motor 11 replenishes, continue to regulate little stroke stepper motor 10 then and accurately locate, the position relation between arm 91 and 92 returns to the lock-out state position.

For realizing control as shown in Figure 2, the present invention has designed the analysis and Control system shown in Fig. 3 system module figure.Control module 83 is connected with execution module 82 with feedback module 81 respectively, optical signals optical inductor 7 receives and is sent to optical diode amplification filtering part 811 and amplifies and filtering, convert frequency signal to by V/F conversion portion 812, feed back to control module 83 by control and tcp data segment 813 again.Control module 83 can adopt computing machine to realize.Control module 83 is set up communication and control DA converter by microcontroller 822 and DA converter 821, high voltage expanded circuit 823 is used to amplify the signal of DA converter output, makes it be enough to promote the running of little stroke stepper motor 10 and big stroke stepper motor 11.In conjunction with the control block diagram of Fig. 4 as seen by optical diode detect the light intensity signal that obtains by feedback module 81 amplify, filtering, V/f conversion sends data to control module 83 by RS232, handle according to certain algorithm by control module 83, and then issue an order to execution module 82.Will change optical path difference after execution module 82 is carried out, change the feedback light intensity so again, the light intensity of feedback is detected by optical diode again, and feedback module 81, execution module 82 and control module 83 constitute a closed-loop control.

Circuit specific to reality realizes that for light intensity signal is converted into electric signal, optical inductor 7 adopts optical diode, but the voltage of optical diode output is very low, have only the millivolt level, and signal to noise ratio (S/N ratio) is very low, so little signal can not directly carry out the AD conversion, must be through amplifying.Designed the circuit diagram of the amplifying circuit of optical diode amplification filtering part 811 shown in Figure 5 for this reason, optical diode is a kind ofly to convert incident illumination intensity to its electric current that is directly proportional a kind of electrooptical device, optical diode often needs reverse bias in the course of the work, is-15 volts as the bias voltage that offers optical diode among Fig. 5.Because the electric current of optical diode output is very little, therefore need further to amplify, the amplifier section of optical diode is made up of three parts, at first is the electric current scale-up version amplifying circuit that optical diode is formed with amplifier U1.It is in order to make optical diode be operated in the range of linearity that R1 gets 56 ohm, i.e. output current I _oBe directly proportional with illumination intensity.Capacitor C 1 can filter the HF noise signal of being come out by photodiode.The voltage that amplifies back output through the first order is:

$V_o=\frac{R2}{R1}{I}_o-----(1-10)$

Next is by digital regulation resistance X9C503 and impact damper OP07, U3 among the figure, and the digital zero setting circuit of composition, its effect is negative voltage-V of output _Ref(V _Ref＞0), V then _oAnd V _RefBe input to together afterbody by

$V_{\mathrm{out}}=-(\frac{V_o}{R_3}-\frac{V_{\mathrm{ref}}}{R_4})(R_{X9\mathrm{<figure-callout\; id="104"\; label="C"\; filenames="C20041009182000171.png"\; state="\{\{state\}\}">C</figure-callout>}104}+R_5)-----(1-11)$

Digital regulation resistance X9C104 and amplifier U ₂In the totalizer of forming that reverse enlarging function is arranged.Output voltage is:

R wherein _X9c104It is the resistance value of digital regulation resistance X9C104.

In the closed-loop control that will realize, the interference signal intensity of the laser that handle through particular polarization two bundles be gathered, and then as the criterion of closed-loop control.The interference light signal intensity I of gathering _TotalThe phase differential of the same two-beam that will control

The pass be:

I _total＝I _const+I(φ)-----(1-12)

I wherein _ConstBe a light intensity constant that can not the equal strength beam splitting produces owing to the light beam splitter of experiment in the light path,

It is the homophase potential difference

Relevant intensity variation part.For the sensitivity and the precision that improve control, we wish

Same I _ConstRatio be the bigger the better, and top circuit can help us more ideally to address this problem.

We can think the voltage V of photocurrent after amplifying that optical diode changes by (1-12) formula _oForm V by two parts _ConstWith

That is:

V _o＝V _const+V(φ)-----(1-13)

We can obtain with (1-13) formula substitution (1-11) formula:

Suitably regulate digital regulation resistance X9C503 and change zeroing voltage V _RefCan be so that in first bracket of following formula

$V_{\mathrm{out}}=-(\frac{{\mathrm{<figure-callout\; id="3"\; label="V\; const\; R"\; filenames="C20041009182000141.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{const}}}{R_{}}+\frac{V\left(\mathrm{\&phi;}\right)}{R_3}-\frac{V_{\mathrm{ref}}}{R_4})(R_{X9\mathrm{<figure-callout\; id="104"\; label="C"\; filenames="C20041009182000171.png"\; state="\{\{state\}\}">C</figure-callout>}104}+R_5)-----(1-14)$

$V_{\mathrm{out}}=-\frac{V\left(\mathrm{\&phi;}\right)}{R_3}(R_{X9\mathrm{<figure-callout\; id="104"\; label="C"\; filenames="C20041009182000171.png"\; state="\{\{state\}\}">C</figure-callout>}104}+R_5)-----(1-15)$

First and the 3rd offset and almost only right Amplify.That is:

According to top parameter, suitably adjust digital regulation resistance R _X9c503With the constant intensity part I in the light signal _ConstOffset and select suitable R again _X9c104Resistance just in time just in time amplifies the changing unit in the light signal and becomes 0～-the 10V scope, can make full use of the precision of V/F conversion.

The variation of the feedback light intensity that the interference that extraneous little vibration caused that is subjected to owing to system causes is a low frequency, therefore need further carry out Filtering Processing through the voltage after amplifying, native system has used bivalent high-pass filter, and its schematic diagram as shown in Figure 6.

The V/F conversion is about to the frequency that voltage transitions Cheng Yuqi is directly proportional, it is a kind of special AD conversion method, this conversion method has many good qualities, in this way the reason of maximum is when gathering light signal: the V/F transfer process is to the continuous integration of input signal, have that the noise that makes in the light signal causes at random or the high frequency variable reach the advantage of balance.The circuit of V/F conversion portion 812 as shown in Figure 7, the input analog voltage scope of this circuit is 0～-10V, output frequency is 0～200KHz, nonlinearity is 0.03%.Mainly be made up of chip LM331 and TL082, the rheostatic resistance of the 2K above in use suitably adjusting can be regulated the full scale frequency.In order to obtain the best linearity, should standardsizing rheostat R16 make as far as possible that the current potential of crus secunda of TL082 is 0.If electric capacity or the resistance R of change integrating capacitor C4 ₁₄Resistance, can regulate conversion gain, integrating capacitor C4 should use the polyester alkene electric capacity of high stability.If wish to obtain higher full scale frequency, can be with AD652 as the V/F switching device, its full scale output frequency can reach 2M, and the nonlinearity erron of this moment has only 0.02%.

Because control module 83 adopts computing machines to realize, therefore control and tcp data segment 813 adopt and are made of single-chip microcomputer 89C2051, MAX232, and this is a kind of hardware combinations mode of very traditional same computer interconnection.By the counter T0 of 89C2051 the frequency of V/F converter output being carried out periodicity counting finishes AD and changes.In fact change the cycle to frequency measurement, will change the precision of AD conversion, can send order to single-chip microcomputer by computing machine and be provided with measuring period, therefore is easy to write to finish by suitable single-chip microcomputer and computer program freely change the AD conversion accuracy.It is cost that the precision of VF conversion improves to reduce slewing rate, if therefore can freely change conversion accuracy in experimentation then can find precision to meet the demands and the slewing rate high best joint of also trying one's best.In experimentation, when only need know the stable case of laser optical power, conversion resolution can be improved, modular converter is worked in be similar to the state of high-precision light power meter; When if desired laser being realized certain control, can suitably turn down resolution and improve slewing rate realize control.In addition, realize that by computer command 89C2051 the change of the value of two digital regulation resistances also is unusual easy to reach.A kind of fairly simple software implementation method is that single-chip microcomputer is in constantly in the V/F conversion cycle, the order that the method for interrupting with serial is come object computer.

Buy from German PI company as the piezoelectric actuator of the little stroke stepper motor 10 of native system, the open loop precision of piezoelectric ceramics is 1 nanometer, and the maximum elongation amount is 60 microns, 100 volts of voltages, and its electric capacity is 7.6 μ f.Its electric capacity is sizable, and so big electric capacity is carried out fast charging and discharging, requires driving circuit that enough big electric current can be provided.Driving circuit must be able to satisfy the upper limit that drives requirement, and the upper limit is assumed to be: 60 microns of 1 millisecond of piezoelectric ceramics elongations.Needed like this electric current is

I＝Q/T＝CU/T＝0.76(A) (1-16)

Present commercial devices is difficult to directly such parameter.In addition driving circuit the electric current that can provide also must be able to reach 100 volts, this magnitude of voltage is the existing inaccessiable far away voltage amplitude of operational amplifier.The upper limit instantaneous power of driving circuit requires to reach 76 watts like this, and this must be a DCPS digitally controlled power source, the step-length precision of its voltage must can satisfy the adjustment of carrying out nanometer scale, just its step-length precision should reach 100/ (60000)=0.0016 volt, and 821 requirements of DA converter are 16 like this.This shows that driving circuit will satisfy following three conditions:

1. peak point current can reach 0.76 ampere;

2. voltage swing can reach 100 volts;

3. the voltage step size precision can reach 0.0016 volt, i.e. the precision of DA conversion can have 16.

The DA converter of 16 precision is existing, but the voltage amplitude of DA converter 821 outputs generally is 5 volts, and maximum current is no more than 10 milliamperes.Therefore we must amplify the voltage that DA changes out again, and this just need use high voltage expanded circuit 823.The common operational amplifier of high voltage expanded circuit 823 usefulness is as amplifying core, pipe TIP41C, TIP42C, MJ15025, MJ15024 are increased its voltage expansion its voltage output amplitude and amplified current with two pairs of triodes, its electric current that provides can be up to one ampere, and voltage amplitude can surpass a hectovolt.

In fact execution module 82 is exactly a DCPS digitally controlled power source, and the structure of DCPS digitally controlled power source is made up of microcontroller 89c51, DA converter, high voltage expanded circuit.Wherein microcontroller 822 is responsible for communication between the computing machine and control DA converter 821; The voltage of DA converter 821 outputs arrives in the scope of 5V 0, and electric current also has only several milliamperes, needs further to amplify, and can reach hectovolt.The schematic diagram of high voltage expanded circuit 823 as shown in Figure 8.This is made up of pipe with two cover triodes a common operational amplifier.The voltage of operational amplifier is provided by the emitter of triode T1 and T2, and the size of value of power source voltage that is added in its two ends is by R2/R7 and R1/R6 decision.Can calculate the voltage swing that is added in the amplifier two ends is:

V ₊＝(60*3.6k/(3.6k+10k)-V _be)≈15V (1-17)

This is in the normal working voltage scope of common operational amplifier.When operational amplifier output current when changing, its supply voltage V ₊And V _-Electric current change thereupon, so the collector current of transistor T 3 and T4 also will produce corresponding the variation.This variable-current is added in respectively between the base stage and emitter of T3 and T4 at R5 and the ohmically voltage drop of R4 collector 1K.Because T3, the emitter of T4 receives respectively+60V and-the 60V power supply, so the change in voltage at load two ends is positive and negative 59V near positive and negative 60V herein.Theoretically, the degree of expansion of the output voltage amplitude of sort circuit is the restriction that is not subjected to assembly.Because Q3, Q4 also has the electric current amplification, so the output power of circuit increases.Capacitor C has the effect that improves the circuit high frequency response, and can improve the dynamic stability of circuit.

Computing machine of the present invention adopts the PID control method to control the operation of little stroke stepper motor and big stroke stepper motor in real time.If carry out PID control, the data of then obtaining have no rule, irregularly change because phase differential is interference along with the external world, therefore ought to obtain a time dependent figure of light intensity that has no rule.If but having carried out PID control, phase differential will be locked, feeds back light intensity like this and also can not change substantially, and the data that measure just should be straight lines.As shown in Figure 9, if give the bump that the external world is unexpected, cause phase differential to depart from equilibrium value, by the effect of PID control, system can get back to the equilibrium position very soon, and balance has completely just been got back to by system in less than the time in a second as seen from the figure.

Claims (7)

1. control system of large stroke nanometer precision location, comprise light source (1), two half-reflecting half mirrors (2) (3), interferometer, a half-wave plate (4), a quarter-wave plate (5), an analyzer (6), analysis and Control system (8), (1) was divided into two-beam after inciding first half-reflecting half mirror (2) to light path from light source, incide two arms (91) (92) of interferometer respectively, merge into a branch of light by the light of the first arm (91) light back by half-wave plate (4) and at second half-reflecting half mirror (3) by second arm (92), inject the optical inductor (7) of analysis and Control system (8) afterwards by quarter-wave plate (5) and analyzer (6), second arm (92) that it is characterized in that interferometer is installed on the stepper motor of multi-stage accuracy, the minimum stroke precision of stepper motor is a nanoscale, and control end is connected with analysis and Control system (8);

The stepper motor of described multi-stage accuracy is made of a little stroke stepper motor (10) and a big stroke stepper motor (11), the stroke accuracy of big stroke stepper motor (11) is not more than 2 times of little stroke stepper motor (10) range, and little stroke stepper motor (10) is connected with analysis and Control system (8) respectively with the control end of big stroke stepper motor (11);

Described analysis and Control system (8) comprising:

Be used to the feedback module (81) surveying weak one and convert thereof into digital signal corresponding;

Be used to adjust the execution module (82) of interferometer second arm (92) position;

Be used for the control module (83) that control of realization center and data transmit;

Control module (83) is connected with execution module (82) with feedback module (81) respectively.

2. control system of large stroke nanometer precision location according to claim 1 is characterized in that described little stroke stepper motor (10) is the piezoelectric micromotor stroke device of nanometer for precision.

3. control system of large stroke nanometer precision location according to claim 2 is characterized in that feedback module (81) comprising:

Be used for the optical diode amplification filtering part (811) that light intensity signal extracts and amplifies;

The V/F conversion portion (812) that the back voltage transitions becomes frequency will be amplified;

Be responsible for the order that processing and control module (83) transmits, control first and second digital regulation resistances, and become numeral to pass to the control and the tcp data segment (813) of control module (83) frequency inverted.

4. control system of large stroke nanometer precision location according to claim 3, the amplifying circuit that it is characterized in that optical diode amplification filtering part (811) comprises the electric current scale-up version amplifying circuit of being made up of with first amplifier optical diode, digital zero setting circuit of being made up of first digital regulation resistance and impact damper and the totalizer of being made up of second digital regulation resistance and second amplifier that reverse enlarging function is arranged; The filtering circuit of optical diode amplification filtering part (811) adopts bivalent high-pass filter.

5. control system of large stroke nanometer precision location according to claim 2, it is characterized in that execution module (82) comprises DA converter (821), be responsible for the communication between the same control module (83) and the microcontroller (822) of control DA converter, be used to amplify the high voltage expanded circuit (823) of DA converter output voltage.

6. control system of large stroke nanometer precision location according to claim 2 is characterized in that described control module (83) is computing machine.

7. control system of large stroke nanometer precision location according to claim 6 is characterized in that described control module (83) is to adopt pid control law to control the computing machine of little stroke stepper motor (10) and big stroke stepper motor (11) operation.

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