RU2788943C1 - Method for pointing a laser beam at an object - Google Patents

Abstract

FIELD: laser technology.

SUBSTANCE: invention relates to optical-mechanical instrumentation, to devices for pointing a laser beam at objects in space. The method for pointing a laser beam at an object includes rotating two optical wedges installed along the beam, determining the angle of rotation of each optical wedge according to the specified ratios for the necessary increment of the beam coordinate in a rectangular coordinate system. The value of the required increment of the beam coordinates is determined as a guidance error, while the coordinates of the object and the beam in the polar coordinate system are determined by the coordinates in the rectangular coordinate system, the necessary increment of the coordinate is worked out automatically by turning the two optical wedges together, simultaneously controlling the polar radius, turning the wedges at the same angles in different directions, and the polar angle by turning the same wedges at the same angles in one direction.

EFFECT: increase in operational characteristics due to an increase in speed, accuracy and the ability to automatically track and guide the beam to moving spatial objects.

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Description

The invention relates to optical-mechanical instrumentation, in particular to devices for pointing a laser beam at objects in space, and can be used to work in limited angles of precise guidance loops of double-loop guidance systems for laser complexes.

A known method of controlling an optical beam in space, based on the use of an optical wedge with a variable refractive angle, resulting from the rotation of one of the lenses of the two-lens system around a point located on the optical axis. This method makes it possible to deploy an optical beam along any trajectory, however, its use is limited by a complex optical-mechanical design, and even at small values of the angle of rotation of the movable lens, the quality of the optical image deteriorates due to the appearance of non-centered aberrations in the lenses [1].

A known method of deflection of the optical beam separate rotation of the two optical wedges around the optical axis of the optical device, parallel to the deployable beam [2]. This method allows the optical beam to be deployed along any trajectory and, in particular, along one of the following: rosette, helical, cycloidal, circular and horizontal, each of which can be obtained only at a certain ratio of optical wedge rotation speeds. This method of deploying an optical beam requires large angles of rotation of the optical wedges to ensure the deployment of the optical beam along any trajectory, including for small sweep amplitudes. In addition, the disadvantage of this method is the inability to automatically track and point the beam at moving spatial objects.

The closest in technical essence to the proposed method is the method of deploying an optical beam [3] by separately rotating two optical wedges installed along the beam, the edges of the optical wedges are preliminarily oriented non-parallel to each other, and the angle of rotation of one of the optical wedges is determined from the ratio: F ₁ \u003d K ₁ A 2 x-A _x (K ₂ +K ₃ A 2 x) + K ₄ A _y A 2 x, and the angle of rotation of the other optical wedge is determined from the relationship: F ₂ \u003d K ₅ A 2 y-A _y ( K ₆ +Y ₇ A 2 y)+K ₈ A _x A 2 y, where F ₁ , F ₂ - angles of rotation of the optical wedges relative to the initial state; K ₁ .... K ₈ - coefficients determined by the optical characteristics of each of the wedges; A _x , A _y - increments of the angular coordinates of the beam on the deployment trajectory, x, y - angular coordinates of a point on the deployment trajectory.

The disadvantages of this method are low speed and accuracy due to the cumbersomeness of the necessary computational procedures for the angles of rotation of the wedges and the complexity of the preliminary procedures for orienting the edges of the optical wedges. In addition, the disadvantage of this method is the inability to automatically track and point the beam at moving spatial objects with high accuracy.

The objective of the invention is to create a method for pointing a laser beam at an object with improved performance by increasing its speed, accuracy and the ability to automatically track and point the beam at moving spatial objects.

The problem is solved by the fact that in the known method of pointing a laser beam, including the rotation of two optical wedges installed along the beam, determining the angle of rotation of each optical wedge according to the given ratios for the required increment of the beam coordinate in a rectangular coordinate system, the value of the required increment of the beam coordinate is determined as beam pointing error from the relations:

Δρ=ρ ₁ -ρ ₂ , where: Δρ - pointing error of the polar radius of the beam mark; ρ ₁ - polar radius of the mark of the object; ρ ₂ - polar radius of the mark of the beam; Δϕ=ϕ ₁ -ϕ ₂ , where: Δϕ - pointing error of the polar angle of the beam mark; ϕ ₁ - polar angle mark of the object; ϕ ₂ - polar angle mark of the beam; in this case, the coordinates of the object and the beam in the polar coordinate system are determined by the coordinates in the rectangular coordinate system from the relations:

ϕ₁=arctg Y₁/X₁; ϕ₂=arctg Y₂/X₂,

ϕ ₁ =arctg Y ₁ /X ₁ ; ϕ ₂ \u003d arctg Y ₂ /X ₂ ,

where: X ₁ , Y ₁ and X ₂ , Y ₂ are the coordinates of the object and the beam, respectively, in a rectangular coordinate system; different sides, and a polar angle, turning the same wedges at the same angles in one direction.

The proposed method of aiming a laser beam at an object is carried out in accordance with the block diagram of the laser beam guidance system as follows (Fig. 1). To rotate wedges 1 and 2, two gearless drives 3 and 4 are used based on ring electric motors (each wedge has its own motor). To control the drives, information is used from the television receiver 5 about the coordinates of the object and the beam mark, obtained in a rectangular coordinate system (X and Y coordinates), these values are converted in the coordinate converter 6 into the values of polar radii ρ ₁ and polar angles ϕ _{1 of} object marks and polar radii ρ ₂ and polar angles ϕ ₂ beam marks, using the relationship:

ϕ₁=arctg Y₁/X₁; ϕ₂=arctg Y₂/Х₂,

ϕ ₁ =arctg Y ₁ /X ₁ ; ϕ ₂ \u003d arctg Y ₂ /X ₂ ,

where: X ₁ , Y ₁ and X ₂ , Y ₂ - coordinates respectively of the object and the beam in a rectangular coordinate system. The values of the polar coordinates of the object and the marks of the beam are fed to the discriminators 7 and 8, in which the errors of aiming the beam at the object in the field of view of the receiver are calculated as a mismatch between the mark of the object (in the receiver, polar coordinates ρ ₁ ϕ ₁ ) and the mark of the beam (in the receiver, polar coordinates ρ ₂ ϕ ₂ ) (Fig. 2). Moreover, the discriminator 7 determines the mismatch (pointing error) of the polar radii Δρ, and the discriminator 8 determines the mismatch (pointing error) of the polar angles Δϕ. The signals from the output of the discriminators enter the adders 9 and 10, and in the adder 9 the signals Δρ and Δϕ with the same signs are added, and in the adder 10 the signals Δρ and Δϕ with opposite signs are summed. That is, the summed pointing errors Δρ and Δϕ are calculated and fed to drive control. In FIG. Figure 2 shows the location of the object mark and the ray mark in the first quadrant of the coordinate plane, when the X and Y coordinates are positive, otherwise, when determining the value of the polar angle, it is necessary to take into account in which quadrants these marks are located.

The laser beam guidance system in accordance with the block diagram works according to the proposed method as follows. The upper branch of the circuit will control the value of the polar radius of the beam mark by synchronously turning the wedges in different directions, for which “+Δρ” is applied to one drive, and “-Δϕ” to the other. At the same time, the lower branch of the circuit, generating an additional signal for the same engines, will control the synchronous rotation of the same wedges by Δϕ in the same direction, thereby controlling the polar angle of the beam mark. Here, in the adders 9 and 10, the control signals are algebraically summed, the drives (each!) work out the final total (Δϕ+/-Δρ) signal of their channel, realizing tracking by errors converted into polar coordinates. Thus, the automatic guidance mode is carried out. It is essential that one pair of optical wedges is sufficient for automatic operation according to the proposed method, while independent beam deflection in automatic mode in rectangular X and Y coordinates requires two pairs of wedges, which can cause mutual influence of drives along X and Y coordinates and lead to additional pointing errors.

The ability of the device to operate in auto-magic mode by an error measured directly in the receiving device makes it possible to ensure high speed and accuracy of beam guidance. Due to the exclusion of complex procedures for preliminary adjustment of the edges of the wedges, the presence of rigid kinematic connections between the rotating parts of the device, which exclude backlash and elastic deformations in the structural elements that transmit torque, a high accuracy of the structure is ensured, which increases the accuracy of guidance.

Sources of information

1. Eskov D.N. Automatic optical image stabilization. - L .: Mashinostroenie, 1988, p. 54-58, fig. 3.2(a).

2. Katys G.P. Automatic scanning. - M.: Mashinostroenie, 1969, p. 227-230.

3. Patent RU 2097811 C1 publ. 1997.11.27 - prototype.

Claims (14)

A method for pointing a laser beam at an object, which includes turning two optical wedges installed along the beam, determining the angle of rotation of each optical wedge according to given ratios for the required increment of the beam coordinate in a rectangular coordinate system, characterized in that the value of the required increment of the beam coordinate is determined as a pointing error beam from the ratios: Δρ=ρ ₁ -ρ ₂ where: Δρ - pointing error of the polar radius of the beam mark; ρ ₁ - polar radius of the mark of the object; ρ ₂ - polar radius of the mark of the beam; Δϕ=ϕ ₁ -ϕ ₂ , where: Δϕ - pointing error of the polar angle of the beam mark; ϕ ₁ - polar angle mark of the object; ϕ ₂ - polar angle mark of the beam; in this case, the coordinates of the object and the beam in the polar coordinate system are determined by the coordinates in the rectangular coordinate system from the relations:

ϕ ₁ =arctg Y ₁ /X ₁ ; ϕ ₂ \u003d arctg Y ₂ /X ₂ , where: X ₁ , Y ₁ and X ₂ , Y ₂ are the coordinates of the object and the beam in a rectangular coordinate system, respectively, the required increment of the coordinate is worked out automatically, turning two optical wedges in connection, simultaneously controlling the polar radius, turning the wedges at the same angles in different directions , and polar angle, turning the same wedges at the same angles in one direction.

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