CN100495119C - Three point dynamic laser collimation system - Google Patents

Abstract

The three-point dynamic laser collimation system of the invention belongs to the laser cavity collimation technical field and the laser active damping technical field. The laser collimation system regards three sets of piezoelectric ceramics symmetrically installed as the drive element of the collimation system, and regards an optical adjustment mirror as an optical path adjustment element. The piezoelectric ceramics are high speed dynamically adjusted through the returned optical path information by the collimation system, and the closed loop adjustment of the collimation system is achieved by compensating the optical path differences by an optical adjustment mirror. The laser light beam can keep a high speed dynamic collimation, so the quality of the light beam is improved. The invention has the advantages of light system weight, simple structure, convenient installation, large adjustment range, rapid response speed and good system linearity.

Description

Three point dynamic laser collimation system

Technical field

The present invention relates to laser optical cavity collimation technique field and laser active damping technical field, relate in particular to a kind of high speed dynamic laser collimation system.

Background technology

Existing dynamic Laser colimated light system is to adopt 4 quadrant detector (QPD) to detect the error information of light path, and adopts four groups of (or two groups) Piezoelectric Ceramic optics to adjust mirror, thereby reaches the collimation to laser beam.Dynamic collimation system with four groups of piezoelectric ceramics is an example, i.e. two groups of piezoelectric ceramics of adjusting horizontal directions, two groups of piezoelectric ceramics of adjusting vertical direction, its principle of work is, semiconductor laser sends laser, become directional light behind the laser process collimator and extender device, light beam returns by former road after adjusting mirror, shine 4 quadrant detector (QPD) after making beam steering by beam splitter, QPD detects the error information of light path and imports CPU into and carries out data processing, utilize control algolithm to calculate the magnitude of voltage of drive pressure electroceramics, by high precision nanometer micro-displacement driver drive pressure electroceramics, adjust the mirror rotation thereby drive, adjust the vibrations light path and gets back to perfect condition, realize the closed-loop dynamic adjustment of colimated light system up to light beam.When the piezoelectric ceramics of adjusting direction was two groups, the piezoelectric ceramics of promptly adjusting horizontal direction and adjustment vertical direction respectively was one group, needs to increase two-dimentional incline hinge, makes that an end is fixed when adjusting, thereby end driving realizes dynamically adjusting.

The shortcoming of existing dynamic Laser colimated light system is: when adopting four groups of Piezoelectric Ceramic, because of the symmetry to four groups of piezoelectric ceramics requires height, and difficulty is installed; When adjusting the arbitrarily angled placement of mirror, be easy to make wherein one group do not stress (or being in vacant state), thereby the Piezoelectric Ceramic system is intercoupled, its dynamic perfromance is very poor; The sensing range of this system is little, and detected misalignment signal is non-linear.When adopting two groups of piezoelectric ceramics, because of needs two dimension incline hinge, so volume is big, and weight is big, and difficulty is debug in system's processing; Be subjected to the influence of hinge (elastic mechanism), the response speed of range of adjustment and system conditions each other, and the degree of freedom of system is few, and adjustment is little with sensing range, and detected misalignment signal is non-linear.

Summary of the invention

The purpose of this invention is to provide a kind of three point dynamic laser collimation system, it has the advantage that system weight is light, simple in structure, easy for installation, range of adjustment is big, response speed is fast, the system linear degree is good.

In order to achieve the above object, technical scheme of the present invention is as follows:

Three point dynamic laser collimation system is mainly by laser instrument 1, beam expander 2, polarization beam apparatus (Polarizing BeamSplitter; PBS) 3, reflective mirror 4, focusing objective len 5, sensitive sensor PSD and signal processing circuit 6, three-dimensional microdrive 7, three-dimensional micro-displacement sensor 8, A/D Acquisition Circuit 9, computer system 10, D/A change-over circuit 11 and three road high-voltage driving circuits 12 are formed, laser instrument 1 emission laser signal, incide on the reflective mirror 4 after laser signal process beam expander 2 and polarization beam apparatus 3 shapings, the reflected light of reflective mirror 4 shines on the photosurface of position sensitive detector PSD through focusing objective len 5, reflected light obtains and the relevant electric signal of the relative position of laser beam on sensitive sensor PSD after passing through sensitive sensor PSD and signal processing circuit 6 processing, and this electric signal is transferred to computer system 10 after changing by A/D Acquisition Circuit 9; Three-dimensional micro-displacement sensor 8 outputs three tunnel of installing on three groups of piezoelectric ceramics of the three-dimensional microdrive 7 on the reflective mirror 4 are transferred to computer system 10 with the proportional electric signal of deformation of piezoelectric ceramics, this electric signal after changing by A/D Acquisition Circuit 9; Two path signal is exported to D/A change-over circuit 11 after handling through computer system 10, D/A change-over circuit 11 is converted into analog electrical signal, after the amplification of this analog electrical signal through three road high-voltage driving circuits 12, drive three groups of piezoelectric ceramics of three-dimensional microdrive 7, thereby adjust the pitch angle of reflective mirror 4.

The invention has the beneficial effects as follows: utilize position detecting element PSD and three groups of piezoelectric ceramics micro-displacement driving device to realize that the closed loop of colimated light systems detects control and decoupling zero is controlled, have simple in structure, easy for installation, system weight is light, range of adjustment is big, response speed is fast, the system linear degree is good, the precision advantages of higher.

Description of drawings

Fig. 1 is the structured flowchart of three point dynamic laser collimation system of the present invention.

Fig. 2 is the schematic diagram of three point dynamic laser collimation system of the present invention.

Fig. 3 is a bikini dynamic collimation structural representation of the present invention.

Fig. 4 is the driving model figure of three point dynamic laser collimation system of the present invention.

Fig. 5 is the decoupling zero control structure synoptic diagram of three point dynamic laser collimation system of the present invention.

Fig. 6 is the curve map of three tunnel Piezoelectric Ceramic Coupling simulation results of the present invention.

Fig. 7 is the curve map of three road piezoelectric ceramics simulation results after the decoupling zero of the present invention.

The synoptic diagram of beam trajectory when Fig. 8 is the arbitrarily angled deflection of reflective mirror of the present invention.

Among the figure: 1, laser instrument, 2, beam expander, 3, PBS, 4, reflective mirror, 5, focusing objective len, 6, PSD and signal processing circuit, 7, three-dimensional microdrive, 8, three-dimensional micro-displacement sensor, 9, the A/D Acquisition Circuit, 10, computer system, 11, D/A change-over circuit, 12, three road high-voltage driving circuits, 13, collimator apparatus, 14, laser instrument, 15, optics is adjusted mirror, and 16, piezoelectric ceramics, 17, beam splitter, 18, beam expander, 19, position sensitive detector, 20, condenser lens, 21, digital signal processor, 22, laser beam, 23, optics adjusts mirror.

Embodiment

Below in conjunction with accompanying drawing the present invention is done description in further detail:

Three point dynamic laser collimation system is a high-precision high-speed real time processing system, and the structure of this system is formed as shown in Figure 1.Incide on the reflective mirror 4 after laser that laser instrument 1 sends is through beam expander 2, polarization beam apparatus 3 shapings, its reflected light shines position sensitive detector (Position Sensitive Detector through behind focusing objective len 5; PSD) on the photosurface, obtain and the relevant electric signal of the relative position of laser beam on PSD with signal processing circuit 6, by being transferred to computer system 10 after 9 conversions of A/D Acquisition Circuit through opto-electronic conversion; Simultaneously, three-dimensional micro-displacement sensor 8 outputs three tunnel of installing on three groups of piezoelectric ceramics of three-dimensional microdrive 7 and the proportional electric signal of deformation of piezoelectric ceramics are through being transferred to computer system 10 after 9 conversions of A/D Acquisition Circuit.After these input signals are handled through computer system 10, obtain output valve according to control algolithm, after 11 conversions of D/A change-over circuit, amplify three groups of piezoelectric ceramics of the three-dimensional microdrive 7 of rear drive through three road high-voltage driving circuits 12, thereby adjust the pitch angle of reflective mirror 4, realize the purpose of beam collimation.

Bikini dynamic collimation device adopts PSD to detect the error information of light path on a large scale, thereby and adopts three groups of Piezoelectric Ceramic optics to adjust mirrors to reach collimation to laser beam.For guaranteeing that collimator apparatus can reflect the error information of laser beam in real time accurately, need make the detection light beam of colimated light system and the working beam of laser instrument be total to light path, could accurately compensate the light path deviation that causes by vibrations like this.

As shown in Figure 2, it is the schematic diagram of three point dynamic laser collimation system.The inside of collimator apparatus 13 comprises semiconductor-assisted laser instrument and detection control apparatus, and it is fixing by three piezoelectric ceramics 16 that optics is adjusted mirror 15.During work, semiconductor laser 14 sends collimated light, by becoming directional light behind the beam expander 18, light beam returns by former road after adjusting mirror 15, make beam steering by beam splitter 17, shine position sensitive detector (PSD) 19 behind the line focus lens 20, PSD detects the error information of light path and imports digital signal processor (Digital Signal Processor into; DSP) 21 carry out data processing, utilize control algolithm to calculate the magnitude of voltage of drive pressure electroceramics, by high precision nanometer micro-displacement driver drive pressure electroceramics, adjust mirror 15 rotations thereby drive, adjust the vibrations light path and get back to perfect condition, realize that the closed loop of colimated light system is dynamically adjusted at a high speed up to light beam.

The precision of colimated light system depends primarily on the precision of Photoelectric Detection, and native system selects for use high-performance PS D as photo-electric conversion element for this reason.PSD converts photocurrent to voltage, controls the flexible to reach close-loop feedback control of piezoelectric crystal.In order to obtain high-precision laser detection precision, this circuit requirement can directly detect nanoscale micrometric displacement precision, therefore, on the circuit design, electric elements select for use and concrete the making on all should fully satisfy requirements such as highly sensitive, good stability, strong interference immunity; Simultaneously, require this signal processing circuit can realize close-loop feedback fast.So the signal Processing frequency response of circuit is wide, dynamic response wants fast.

The PSD signal of sensor is fainter, so the detection of signal will be passed through amplifier, to increase signal amplitude, adapts to the requirement of further handling.For requirements such as the precision that guarantees input, response speeds, amplifier should have performances such as high-gain, high stability, broad passband, low drift and low noise.The photo-signal that adopts operational amplifier directly PSD to be received converts voltage signal to, and the variation that is about to spot displacement is converted to differential voltage Δ V _x, Δ V _yOutput is directly imported the high stability power amplifier through integration, processing and amplifying again, output voltage is amplified to ± the 150V scope in, can directly drive the flexible of micrometric displacement device, realize close-loop feedback.

As shown in Figure 3, it is a bikini dynamic collimation structural representation.On the pedestal of reflective mirror, choose symmetrical A, B, C at 3 as the position that piezoelectric ceramics and micro-displacement mechanism thereof are installed, the positional information that corresponding strain-type displacement transducer is used for returning piezoelectric ceramics has been installed on the micro-displacement mechanism of piezoelectric ceramics.Three groups of piezoelectric ceramics are independently controlled, and constitute three control loops.This shows that any one loop changes and all can exert an influence to two other loop, therefore intercouple between three loops.Because the existence meeting of coupling obviously reduces the regulation quality of control system, under the coupling serious situation, system can't normally be moved, simultaneously, because the change of asymmetry, the discontinuity when vertically placing and surrounding environment that piezoelectric ceramics is installed can make its duty change, therefore, the present invention utilizes following control algolithm to realize the decoupling zero control of three point dynamic laser collimation system.

In order to guarantee the stable and response speed of colimated light system, the decoupling zero control algolithm that is adopted needs dynamically to obtain by the field coupled relation of three groups of each control loops of piezoelectric ceramics, include the piezoelectric ceramics displacement information in coupled relation, be independent of coordinate system, after the decoupling zero, each control loop can be separate, presses separately independently control algolithm drive pressure electroceramics, to realize the dynamic real-time collimation.Concrete steps are as follows:

The first step: set up the decoupling zero controlling models

According to bikini dynamic collimation structure foundation colimated light system driving model as shown in Figure 4, wherein, A, B, 3 of C are three groups of piezoelectric ceramics that symmetry is installed.For obtaining the mathematical model of control system, set up coordinate system as shown in Figure 4, its corresponding coordinate is A (x ₁, y ₁, z ₁), B (x ₂, y ₂, z ₂), C (x ₃, y ₃, z ₃).In the X of level crossing and the declination angle of Y direction _x, φ _yAnd the vertical height h at center can be expressed as:

$\sin {\mathrm{\&phi;}}_x={\mathrm{\&phi;}}_x=\frac{{\mathrm{\&Delta;Z}}_x}{d_x}=\frac{\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_3}-\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_2}}{\stackrel{\&OverBar;}{x_3}-\stackrel{\&OverBar;}{x_2}}---\left(1\right)$

$\sin {\mathrm{\&phi;}}_y={\mathrm{\&phi;}}_y=\frac{{\mathrm{\&Delta;Z}}_y}{d_y}=\frac{2\stackrel{\&OverBar;}{Z_1}-\stackrel{\&OverBar;}{Z_2}-\stackrel{\&OverBar;}{Z_3}}{\stackrel{\&OverBar;}{{2y}_1}-\stackrel{\&OverBar;}{y_2}-\stackrel{\&OverBar;}{y_3}}---\left(2\right)$

$h=\frac{\stackrel{\&OverBar;}{Z_1}+\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_2}+\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_3}}{3}---\left(3\right)$

In the formula,

Moving average for piezoelectric ceramics.

Second step: the dynamic solution of coupling transfer matrix

The dynamic adjustment of piezoelectric ceramics is by driving voltage control, so the performance variable of this decoupling and controlling system is for controlling the voltage V of three piezoelectric ceramics respectively ₁, V ₂, V ₃, the Be Controlled variable then is the adjustment angle φ of reflective mirror _x, φ _yAnd h.Can get φ by formula (1), (2), (3) _x, φ _yAnd the relation between h and the piezoelectric ceramics each point displacement variable can be described as:

$\left[\begin{array}{c}{\mathrm{\&phi;}}_x\\ {\mathrm{\&phi;}}_y\\ h\end{array}\right]=\left[\begin{array}{ccc}{a}_{11}& a_{12}& a_{13}\\ a_{21}& a_{22}& a_{23}\\ a_{31}& a_{32}& a_{33}\end{array}\right]\left[\begin{array}{c}\stackrel{\&OverBar;}{Z_1}\\ \stackrel{\&OverBar;}{Z_2}\\ \stackrel{\&OverBar;}{Z_3}\end{array}\right]---\left(4\right)$

Transitive relation changes because asymmetry between three piezoelectric ceramics and stressed unevenness cause being coupled, and the present invention finds the solution this function with dynamic method, the dynamic auto calibration of realization colimated light system.If the displacement of piezoelectric ceramics and performance variable V _iFollowing relation is arranged:

$\left\{\begin{array}{c}{Z}_1=f_1(V_1,{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">V</figure-callout>}}_2,V_3)\\ {\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_2{=f}_2(V_1,{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">V</figure-callout>}}_2,V_3)\\ {\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_3=f_3(V_1,{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">V</figure-callout>}}_2,V_3)\end{array}\right.---\left(5\right)$

Corresponding Increment Matrix form is:

$\left[\begin{array}{c}\mathrm{\&Delta;}{Z}_1\\ \mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_2\\ {\mathrm{\&Delta;<figure-callout\; id="3"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_3\end{array}\right]=\left[\begin{array}{ccc}{f}_{11}& f_{12}& f_{13}\\ f_{21}& f_{22}& f_{23}\\ f_{31}& f_{32}& f_{33}\end{array}\right]\left[\begin{array}{c}\mathrm{\&Delta;}{V}_1\\ {\mathrm{\&Delta;<figure-callout\; id="2"\; label="V"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">V</figure-callout>}}_2\\ \mathrm{\&Delta;}{V}_3\end{array}\right]---\left(6\right)$

Give three piezoelectric ceramics voltage increments respectively, for example to piezoelectric ceramics A, given increment is Δ V ₁, at this moment the displacement variable of the piezoelectric ceramics that is returned by displacement transducer is Δ Z ₁, Δ Z ₂, Δ Z ₃The analytic system structure as can be known

${\mathrm{<figure-callout\; id="11"\; label="f"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">f</figure-callout>}}_{11}=\frac{{\mathrm{\&Delta;Z}}_1}{\mathrm{\&Delta;}{V}_1},{\mathrm{<figure-callout\; id="21"\; label="f"\; filenames="C200710157919E00092.png"\; state="\{\{state\}\}">f</figure-callout>}}_{21}=\frac{{\mathrm{\&Delta;<figure-callout\; id="2"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_2}{\mathrm{\&Delta;}{V}_1},f_{31}=\frac{{\mathrm{\&Delta;<figure-callout\; id="3"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_3}{\mathrm{\&Delta;}{V}_1}---\left(7\right)$

Equally, to piezoelectric ceramics B, C, can obtain its matrix coefficient:

${\mathrm{<figure-callout\; id="12"\; label="f"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">f</figure-callout>}}_{12}=\frac{\mathrm{\&Delta;}{Z}_1^{\&prime;}}{\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">V</figure-callout>}}_2},{\mathrm{<figure-callout\; id="22"\; label="f"\; filenames="C200710157919E00101.png"\; state="\{\{state\}\}">f</figure-callout>}}_{22}=\frac{\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_2^{\&prime;}}{\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">V</figure-callout>}}_2},f_{32}=\frac{\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_3^{\&prime;}}{\mathrm{\&Delta;}{V}_2}---\left(8\right)$

${\mathrm{<figure-callout\; id="13"\; label="f"\; filenames="C200710157919E00092.png"\; state="\{\{state\}\}">f</figure-callout>}}_{13}=\frac{\mathrm{\&Delta;}{Z}_1^{\&prime;\&prime;}}{\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="V"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">V</figure-callout>}}_3},{\mathrm{<figure-callout\; id="23"\; label="f"\; filenames="C200710157919E00101.png"\; state="\{\{state\}\}">f</figure-callout>}}_{23}=\frac{\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_2^{\&prime;\&prime;}}{\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="V"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">V</figure-callout>}}_3},f_{33}=\frac{\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">Z</figure-callout>}}_3^{\&prime;\&prime;}}{\mathrm{\&Delta;}{V}_3}---\left(9\right)$

Three regulators transport function separately is respectively P ₁(S), P ₂(S), P ₃(S), performance variable V then _iAnd the relational matrix F (S) between the displacement variable of piezoelectric ceramics is:

$F\left(S\right)=\left[\begin{array}{ccc}{f}_{11}{P}_1\left(S\right)& f_{12}{P}_2\left(S\right)& f_{13}{P}_3\left(S\right)\\ f_{21}{P}_1\left(S\right)& f_{22}{P}_2\left(S\right)& f_{23}{P}_3\left(S\right)\\ f_{31}{P}_1\left(S\right)& f_{32}{P}_2\left(S\right)& f_{33}{P}_3\left(S\right)\end{array}\right]---\left(10\right)$

Convolution (4), the transfer matrix that is coupled so, i.e. performance variable V _iWith Be Controlled variable φ _x, φ _yAnd the relational matrix between the h is:

$G\left(S\right)=\left[\begin{array}{ccc}{a}_{11}& a_{12}& a_{13}\\ a_{21}& a_{22}& a_{23}\\ a_{31}& a_{32}& a_{33}\end{array}\right]\left[\begin{array}{ccc}{f}_{11}{P}_1\left(S\right)& f_{12}{P}_2\left(S\right)& f_{13}{P}_3\left(S\right)\\ f_{21}{P}_1\left(S\right)& f_{22}{P}_2\left(S\right)& f_{23}{P}_3\left(S\right)\\ f_{31}{P}_1\left(S\right)& f_{32}{P}_2\left(S\right)& f_{33}{P}_3\left(S\right)\end{array}\right]$

$=\left[\begin{array}{ccc}{G}_{11}\left(S\right)& G_{12}\left(S\right)& G_{13}\left(S\right)\\ G_{21}\left(S\right)& G_{22}\left(S\right)& G_{23}\left(S\right)\\ G_{31}\left(S\right)& G_{32}\left(S\right)& G_{33}\left(S\right)\end{array}\right]---\left(11\right)$

Promptly

$\left[\begin{array}{c}{\mathrm{\&phi;}}_x\\ {\mathrm{\&phi;}}_y\\ h\end{array}\right]=G\left(S\right)\left[\begin{array}{c}{V}_1\\ V_2\\ V_3\end{array}\right]---\left(12\right)$

Like this, just can dynamically obtain the coupling transfer matrix, so that realize the automatic calibration of colimated light system by formula (5), (6), (7) and (11).

The 3rd step: decoupling zero Matrix Solving

Native system is three inputs, three output systems, and three piezoelectric ceramics constitute three control loops, and intercouple between three loops, can realize the controlled quentity controlled variable coupling problems preferably by decoupling zero control.

If it is full decoupled that object requires, then the objective matrix of decoupled system need be got a diagonal matrix, even the transport function of coupling branch road is zero, and keeps the transport function of each control channel, is about to objective matrix and gets diagonal matrix

For:

Then the network matrix D (S) of decoupling zero is:

(14)

Wherein, G (S) ^-1Inverse matrix for matrix G (S).

The structure of decoupling zero control as shown in Figure 5, the decoupling zero network is connected in series between Control Network and the coupling object, represents multivariable input and output with the multiple line arrow here.Wherein, R (S) is a performance variable, and C (S) is the Be Controlled variable, and P (S) is the regulator transport function.This decoupling zero network is to be placed in the middle of the forward passage of control system, so, when coupling influence does not also reflect, the corrective action that has just begun decoupling zero, advantage such as it is little therefore to have dynamic deviation, and response speed is fast, and transit time is short, the actual effect of decoupling zero is good.

Characteristic according to piezoelectric element can be a typical second order oscillation element with regulator transport function P (S) equivalence:

$P\left(S\right)=\frac{k}{L_p{\mathrm{<figure-callout\; id="2"\; label="C\; p\; s"\; filenames="C200710157919E00091.png"\; state="\{\{state\}\}">C</figure-callout>}}_p{s}^{}{}^2+R{C}_{p}s+1}---\left(15\right)$

Wherein, R is that current-limiting resistance adds total resistance value behind the piezoelectric element loss resistance; C _pEquivalent capacity for piezoelectric element; L _pBe the equivalent inductance of piezoelectric element, its value is all relevant with quality, rigidity and the equivalent capacitance value of element.

The 4th step: drive pressure electroceramics

After measuring the light beam misalignment signal, according to above formula,, obtain the control voltage of three groups of piezoelectric ceramics respectively to the decoupling zero of system, and respectively to its control.Fig. 6, Fig. 7 demonstrate the step response curve of these system decoupling front and back every interval 1s in three loops respectively, can obviously find out from figure: it is serious to influence each other between first three bar loop of decoupling zero, and system is uncontrollable; Every loop has independently step response after the decoupling zero, has reached the effect of independent control in theory, has realized the full decoupled of coupled system.

Three point dynamic laser collimation system of the present invention is realized the light beam dynamic collimation by driving three piezoelectric ceramics, has six degree of freedom, can realize light beam deflection at any angle and scanning.Adopt the angular resolution of the Chemical oxygen-iodine laser optical cavity autocollimation system of this system development can be better than 0.2 μ rad, repeatable accuracy can reach 1 μ rad, and working range can reach 10mrad.Fig. 7 is the arbitrarily angled quick light beams deflected track of reflective mirror.Experiment shows that this system can reach 4mrad in the collimation scope, and precision is that response speed is better than 20Hz under the condition of 5urad.

Claims (1)

1, three point dynamic laser collimation system, it is characterized in that, this colimated light system is mainly by laser instrument (1), beam expander (2), polarization beam apparatus (3), reflective mirror (4), focusing objective len (5), position sensitive detector PSD and signal processing circuit (6), three-dimensional microdrive (7), three-dimensional micro-displacement sensor (8), A/D Acquisition Circuit (9), computer system (10), D/A change-over circuit (11) and three road high-voltage driving circuits (12) are formed, laser instrument (1) emission laser signal, incide on the reflective mirror (4) after laser signal process beam expander (2) and polarization beam apparatus (3) shaping, the reflected light of reflective mirror (4) shines on the photosurface of position sensitive detector PSD through focusing objective len (5), reflected light obtains and the relevant electric signal of the relative position of laser beam on position sensitive detector PSD after passing through position sensitive detector PSD and signal processing circuit (6) processing, and this electric signal is transferred to computer system (10) after changing by A/D Acquisition Circuit (9); Three-dimensional micro-displacement sensor (8) output three tunnel of installing on three groups of piezoelectric ceramics of the three-dimensional microdrive (7) on the reflective mirror (4) is transferred to computer system (10) with the proportional electric signal of deformation of piezoelectric ceramics, this electric signal after changing by A/D Acquisition Circuit (9); Two path signal is exported to D/A change-over circuit (11) after handling through computer system (10), D/A change-over circuit (11) is converted into analog electrical signal, after the amplification of this analog electrical signal through three road high-voltage driving circuits (12), drive three groups of piezoelectric ceramics of three-dimensional microdrive (7), thereby adjust the pitch angle of reflective mirror (4).

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