CN1312526C - Method for controlling dual-feedback high-precision light beam aiming - Google Patents

Abstract

The present invention relates to a method for controlling dual-feedback high precision light beam aiming. The present invention relates to the technical field of laser control. The present invention comprises the following control steps: a two-dimensional deflection angle value Az, El001 of a light beam is set; according to Az, El and an output value of a displacement sensor in a two-dimensional deflection mirror, the first-level feedback error correction 002 of two-dimensional deflection drive voltage of piezoelectric ceramic in the two-dimensional deflection mirror is carried out; the value 003 of a two-dimensional coordinate XC, YC on a CCD camera of a laser beam is calculated by a computer; the value 004 of an actual two-dimensional deflection angle psi h, psi v is calculated by the computer according to the value of the two-dimensional coordinate XC, YC; psi h and psi v are compared with Az and El, the second-level feedback error correction 005 of the two-dimensional deflection drive voltage of the piezoelectric ceramic is carried out; 006 is completed. The deflection angle of a reflection output light beam of the two-dimensional deflection mirror can be monitored by the present invention in a high precision mode, the two-dimensional deflection mirror is controlled in real time in a feedback mode, and an error is controlled to be not more than 0.5 mu rad.

Description

The control method of dual-feedback high-precision light-beam aiming

Technical field:

What the present invention relates to is the laser control technique field, specifically is a kind of control method of dual-feedback high-precision light-beam aiming.

Background technology:

In the existing laser beam aiming control method, adopt the Piezoelectric Ceramic optical mirror to change the exit direction of light beam, the feedback unit of its closed-loop control is a micro-displacement sensor more.Because optical reflecting mirror is not a desirable rigid body, under the piezoelectric ceramics contractility drives deformation can take place, and then influence the yawing moment of light beam.In the light beam acquiring control method, displacement transducer can only be measured the stroke of piezoelectric ceramics, can't measure the actual deflection amount of optical reflecting mirror.As seen, optical reflecting mirror deformation is the uncertain factor of influence aiming control accuracy, only is difficult to realize high precision light beam control by displacement transducer one-level FEEDBACK CONTROL.

Summary of the invention:

The control method that the purpose of this invention is to provide a kind of dual-feedback high-precision light-beam aiming.The present invention can solve the precision problem that influences control laser beam reflection angle because of the mirror surface deformation of two-dimensional deflection mirror.

It comprises controlled step (001)～(006):

(001) two-dimensional deflection angle value Az, the El of setting laser light beam in computing machine;

(002) computing machine is according to the output valve of the displacement transducer in two-dimensional deflection angle value Az, El and the two-dimensional deflection mirror, and the two-dimensional deflection driving voltage of the piezoelectric ceramics in the two-dimensional deflection mirror is carried out the correction of one-level feedback error;

(003) COMPUTER CALCULATION goes out the two-dimensional coordinate X of laser beam on ccd video camera _c, Y _cValue;

(004) computing machine is according to two-dimensional coordinate value X _c, Y _c, calculate actual two-dimensional deflection angle Ψ _h, Ψ _vValue;

(005) computing machine is with actual two-dimensional deflection angle value Ψ _h, Ψ _vAfter setting two-dimensional deflection angle value Az, El and comparing, the two-dimensional deflection driving voltage of the piezoelectric ceramics in the two-dimensional deflection mirror is carried out the correction of secondary feedback error;

(006) finishes.

The high-precision deflection angle of monitoring out two-dimensional deflection mirror reflection output beam of the present invention's energy carries out real-time FEEDBACK CONTROL to the two-dimensional deflection mirror, its departure≤0.5 μ rad, and have the advantage that step is simple, be easy to promote.

Description of drawings:

Fig. 1 is a controlled step schematic flow sheet of the present invention, and Fig. 2 is the structural representation of embodiment.

Embodiment:

In conjunction with Fig. 1, Fig. 2 present embodiment is described, it comprises controlled step (001)～(006):

(001) two-dimensional deflection angle value Az, the El of setting laser light beam in computing machine;

(002) computing machine is according to the output valve of the displacement transducer in two-dimensional deflection angle value Az, El and the two-dimensional deflection mirror, and the two-dimensional deflection driving voltage of the piezoelectric ceramics in the two-dimensional deflection mirror is carried out the correction of one-level feedback error;

(003) COMPUTER CALCULATION goes out the two-dimensional coordinate X of laser beam on ccd video camera _c, Y _cValue;

(004) computing machine is according to two-dimensional coordinate value X _c, Y _c, calculate actual two-dimensional deflection angle Ψ _h, Ψ _vValue;

(005) computing machine is with actual two-dimensional deflection angle value Ψ _h, Ψ _vAfter setting two-dimensional deflection angle value Az, El and comparing, the two-dimensional deflection driving voltage of the piezoelectric ceramics in the two-dimensional deflection mirror is carried out the correction of secondary feedback error;

(006) finishes.

Described step (003) COMPUTER CALCULATION goes out the two-dimensional coordinate X of laser beam on ccd video camera _c, Y _cValue, X _c, Y _cValue is calculated according to following formula:

$X_c=\frac{\underset{l=1}{\overset{n}{\mathrm{\Σ}}}(g_l-B)u(g_l-B)x_l}{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(g_i-B)u(g_i-B)}$

$Y_c=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(g_i-B)u(g_i-B)y_i}{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(g_i-B)u(g_i-B)}$

N is the number of pixel in the sample window of ccd video camera in the above-mentioned formula, g _iBe the gray-scale value of ccd video camera pixel, B is a sampling threshold, and u (x) is a unit-step function, (x _i, y _i) be the coordinate of ccd video camera pixel; The computing formula of sampling threshold B is:

$B=\frac{\underset{i=1}{\overset{2(W+H)-4}{\mathrm{\Σ}}}{g}_i}{2(W+H)-4}$

W and H are respectively the horizontal and vertical number of pixels of ccd video camera sample window in the above-mentioned formula, and gi is gray-scale value (the situation decision that sampling threshold B value is disturbed by the intrinsic noise of system and sensor and bias light of ccd video camera pixel; Pixel gray-scale value to the sample window edge averages, and can calculate sampling threshold B).

Step (004) computing machine is according to two-dimensional coordinate value X _c, Y _c, calculate actual two-dimensional deflection angle Ψ- _h, Ψ _vValue, Ψ _h, Ψ _vValue is calculated according to following formula:

${\mathrm{\ψ}}_h=\mathrm{arctg}\left(\frac{X_c}{L}\right)$

${\mathrm{\ψ}}_v=\mathrm{arctg}\left(\frac{Y_c}{L}\right)$

In the above-mentioned formula, L is that laser beam is in incoming position center on the deflecting mirror and the vertical range between the CCD test surface.

Claims (3)

1, the control method of dual-feedback high-precision light-beam aiming,

It comprises controlled step (001)～(006):

(001) two-dimensional deflection angle value Az, the El of setting laser light beam in computing machine;

(002) computing machine is according to the output valve of the displacement transducer in two-dimensional deflection angle value Az, El and the two-dimensional deflection mirror, and the two-dimensional deflection driving voltage of the piezoelectric ceramics in the two-dimensional deflection mirror is carried out the correction of one-level feedback error;

It is characterized in that

(003) COMPUTER CALCULATION goes out the two-dimensional coordinate X of laser beam on ccd video camera _C, Y _CValue;

(004) computing machine is according to two-dimensional coordinate value X _C, Y _C, calculate actual two-dimensional deflection angle ψ _h, ψ _vValue;

(005) computing machine is with actual two-dimensional deflection angle value ψ _h, ψ _vAfter setting two-dimensional deflection angle value Az, El and comparing, the two-dimensional deflection driving voltage of the piezoelectric ceramics in the two-dimensional deflection mirror is carried out the correction of secondary feedback error;

(006) finishes.

2, the control method of dual-feedback high-precision light-beam aiming according to claim 1 is characterized in that step (003) COMPUTER CALCULATION goes out the two-dimensional coordinate X of laser beam on ccd video camera _C, Y _CValue, X _C, Y _CValue is calculated according to following formula:

$X_c=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(g_i-B)u(g_i-B)x_i}{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(g_i-B)u(g_i-B)}$

$Y_c=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(g_i-B)u(g_i-B)y_i}{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(g_i-B)u(g_1-B)}$

N is the number of pixel in the sample window of ccd video camera in the above-mentioned formula, g _iBe the gray-scale value of ccd video camera pixel, B is a sampling threshold, and u (x) is a unit-step function, (x _i, y _i) be the coordinate of ccd video camera pixel; The computing formula of sampling threshold B is:

$B=$ $\frac{\underset{i=1}{\overset{2(W+H)-4}{\mathrm{\Σ}}}{g}_i}{2(W+H)-4}$

W and H are respectively the horizontal and vertical number of pixels of ccd video camera sample window, g in the above-mentioned formula _iGray-scale value for the ccd video camera pixel.

3, the control method of dual-feedback high-precision light-beam aiming according to claim 1 is characterized in that step (004) computing machine is according to two-dimensional coordinate value X _C, Y _C, calculate actual two-dimensional deflection angle ψ- _h, ψ _vValue, ψ _h, ψ, value calculate according to following formula:

${\mathrm{\ψ}}_h=\mathrm{arctg}\left(\begin{array}{c}\frac{X_c}{L}\end{array}\right)$

${\mathrm{\ψ}}_r=\mathrm{arct}\left(\begin{array}{c}\frac{Y_c}{L}\end{array}\right)$

In the above-mentioned formula, L is that laser beam is in incoming position center on the deflecting mirror and the vertical range between the CCD test surface.

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