CN-121995971-A - Laser coarse-fine integrated tracking control method and system

CN121995971ACN 121995971 ACN121995971 ACN 121995971ACN-121995971-A

Abstract

A laser coarse-fine integrated tracking control method and a system belong to the technical field of laser communication control and regulation. By constructing the beam direction vector in the three-dimensional space and carrying out inverse rotation operation by combining the current rotary table posture, the camera error can be uniformly returned to the initial base coordinate system under any posture, thereby realizing the geometric consistency resolving and dynamic decoupling control of coarse tracking and fine tracking. The coarse tracking and the fine tracking adopt the same sight vector modeling method to realize the unification of algorithm structures, errors always return to an initial base coordinate system through inverse rotation operation, coupling influence caused by change of the posture of the rotary table is eliminated, a vibrating mirror compensation angle is directly deducted at a sight angle layer, control superposition conflict in a traditional double-ring structure is avoided, matrix multiplication and arctangent operation are only needed under small angle approximation, the method is suitable for an embedded high-speed control system, the rotary table only tracks low-frequency residual errors, and high-frequency vibration of the vibrating mirror is prevented from being transmitted to a mechanical structure.

Inventors

MOU HONGYUAN
WANG XINGXING
DAI LU
HUO ZHANWEI
SUN WEI

Assignees

长光卫星技术股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260409

Claims (10)

1. The laser coarse-fine integrated tracking control method is characterized by comprising the following steps of: s1, converting a coordinate system and variables, namely defining a basic coordinate system and a tracking camera optical axis coordinate system, and converting the actual azimuth angle of the turntable And the actual pitching angle of the turntable Respectively converting into radian form to obtain rotary table azimuth radian representation And turntable pitch arc representation Obtaining the pixel offset of the actual light spot center relative to the light closed loop center ; S2, converting pixel off-target quantity into line-of-sight angle errors, namely calculating physical displacement of an image plane of the tracking camera Calculating the azimuth error of the sight angle of the tracking camera And line of sight angle pitch error Constructing a line-of-sight vector in a tracking camera coordinate system ; S3, solving the coarse tracking instruction azimuth and the pitching angle, namely rotating the base coordinate system to a rotation matrix of the tracking camera optical axis coordinate system under the current posture of the turntable Obtaining line-of-sight vectors in a base coordinate system By Solving the pitch angle of turntable command under coarse tracking And command azimuth ; S4, solving the fine tracking instruction azimuth and the pitching angle, namely calculating a small-angle approximately-compensated sight angle azimuth error residual angle And pitch error residual angle And thus calculate the residual line of sight direction vector after the galvanometer compensation under the camera optical axis coordinate system Will be The equivalent direction vector under the basic coordinate system is obtained after the current rotary table gesture is reversely rotated According to Calculating the pitch angle of turntable command under precise tracking And command azimuth ; S5, solving the command angular velocity, and setting a control period And solving the command pitch angle and the command azimuth angle of the coarse/fine tracking twice before and after the control period to obtain the command pitch angle deviation and the command azimuth angle deviation of the coarse/fine tracking, obtaining the command pitch angle speed and the command azimuth angle speed of the coarse/fine tracking through differentiation, performing first-order low-pass filtering on the obtained command pitch angle speed and the command azimuth angle speed of the coarse/fine tracking, and outputting the filtered command pitch angle speed and command azimuth angle speed as control values.
2. The laser rough and fine integrated tracking control method according to claim 1, wherein a tracking camera viewing angle orientation error is obtained Tracking camera line of sight angle pitch error , Indicating that the focal length of the camera is tracked, , , To track the amount of physical displacement of the camera image plane X-axis, To track the amount of physical displacement of the camera image plane Y-axis, And Are directional symbols.
3. The laser rough and fine integrated tracking control method according to claim 2, wherein a line-of-sight vector in a camera coordinate system By: obtained.
4. The laser rough and fine integrated tracking control method according to claim 3, wherein the line-of-sight vector in the base coordinate system By: obtained.
5. The laser rough and fine integrated tracking control method according to claim 4, characterized in that the method comprises the following steps of Solving the pitch angle of turntable command under coarse tracking And command azimuth Specifically, the method comprises the steps of Defining a resolution form of a turntable command azimuth angle and a command pitch angle: The instruction pitch angle is ; The instruction azimuth angle is ; , 。
6. The laser coarse and fine integrated tracking control method according to claim 5, characterized in that, Small angle approximate compensated azimuth error residual angle ; Small angle approximately compensated pitch error residual angle ; Is the small-angle deflection of the mirror surface corresponding to the azimuth axis of the vibrating mirror, The mirror surface deflection amount corresponding to the pitching axis of the vibrating mirror is small.
7. The laser rough and fine integrated tracking control method according to claim 6, characterized in that the residual line-of-sight direction vector after the galvanometer compensation ; Equivalent direction vector in base coordinate system 。
8. The laser rough and fine integrated tracking control method according to claim 7, characterized in that according to the following Calculating the pitch angle of turntable command under precise tracking And command azimuth The method comprises the following steps: solving the instruction pitching angle of the turntable under fine tracking: ; solving the azimuth angle of the turntable instruction under fine tracking: ; Wherein, the Is equivalent to a direction vector The component in the direction of the X-axis, Is equivalent to a direction vector The component in the direction of the Y-axis, Is equivalent to a direction vector A component in the Z-axis direction; , 。
9. the laser coarse-fine integrated tracking control method according to claim 8, characterized in that, The pitch angle deviation of the coarse/fine tracking command is Wherein To be in control period The commanded pitch angle of the coarse/fine tracking of the previous solution, During the control period The rough/fine tracking instruction pitch angle solved at the next time; the commanded azimuthal deviation for coarse/fine tracking is Wherein To be in control period The commanded azimuth of the coarse/fine trace of the previous solution, To be in control period The instruction azimuth angle of coarse/fine tracking of the last solution; The commanded pitch angle rate for coarse/fine tracking is ; The commanded azimuthal velocity for coarse/fine tracking is 。
10. The laser coarse-fine integrated tracking control system is characterized by comprising a tracking camera (1), a laser ground station turntable (2), a tracking control unit (3), a turntable base (4) and a galvanometer (5); The tracking camera (1) is used for receiving light spots and extracting light spot centers, the laser ground station turntable (2) is used for responding to instructions of the tracking control unit (3) and moving according to the instruction angles and the angular speeds, the tracking control unit (3) is used for controlling the laser ground station turntable (2) and collecting actual azimuth angles, actual pitching angles, tracking camera off-target amount information and vibrating mirror deflection angle information of the laser ground station turntable (2) in real time, the instruction angles and the angular speeds of the laser ground station turntable (2) are calculated by adopting the method of claim 9, the turntable base (4) is used for bearing the laser ground station turntable (2), and the vibrating mirror (5) is used for carrying out fine tracking closed loop.

Description

Laser coarse-fine integrated tracking control method and system Technical Field The invention belongs to the technical field of laser communication control and regulation, and particularly relates to a laser coarse-fine integrated tracking control method and system. Background In a laser communication ground station system, in order to realize stable beam pointing to a remote satellite or an air-based platform, a biaxial mechanical turntable is generally adopted to realize large-range coarse tracking, and a biaxial rapid vibrating mirror is adopted to realize high-precision fine tracking. The system is generally of a coaxial light path structure, a tracking camera acquires the light spot position in real time, and closed-loop pointing stability is realized by controlling the turntable and the galvanometer. In the prior art, the coarse tracking and the fine tracking mostly adopt control strategies that off-target quantity measured by a camera is directly converted into angle errors, a turntable and a vibrating mirror are respectively driven through proportion or PID control, or a simple angle superposition mode is adopted, and the angle compensation quantity of the vibrating mirror is directly superposed to the angle of the turntable. However, the above method has the following technical problems in practical engineering application: 1. Crude tracking and fine tracking resolving system fracture In the existing method, a control model is generally established for coarse tracking and fine tracking respectively, wherein the coarse tracking is used for carrying out angle calculation based on a turntable mechanical coordinate system, and the fine tracking is used for carrying out galvanometer control based on a camera image plane error. The two are not in a unified three-dimensional geometric framework in the mathematical modeling layer, so that a strict coordinate mapping relation is lacking between camera errors and the posture of the turntable, experience distribution is carried out between the fast and slow rings only through control parameters, and theoretical stability analysis is difficult to carry out by the system. 2. Dynamic rotation of error direction caused by change of turntable posture In a biaxial turret structure, the camera optical axis coordinate system rotates as the turret is turned in azimuth or pitch. Therefore, the horizontal pixel error measured by the camera is not consistent with the corresponding actual spatial error direction under different turntable attitudes. The traditional method usually ignores the geometric relation, and directly maps the pixel error into the turntable angle correction amount, thereby bringing error direction distortion, controlling gain to change along with the gesture, and generating abnormal jitter or gain drift when the pitch angle is high or is close to the zenith area. 3. Dynamic coupling exists between the vibrating mirror and the turntable The vibrating mirror is used for compensating high-frequency disturbance, and the rotary table is used for compensating low-frequency drift. Because the two are acted on the same light path, the deflection of the vibrating mirror can change the light beam direction, the rotation of the turntable can change the direction of a camera coordinate system, and if the control calculation is not carried out under a uniform geometric framework, the two are easy to form dynamic coupling. 4. Error mapping lacks pose independence The traditional angle superposition method defaults that the camera pixel direction is fixedly corresponding to the mechanical axis direction of the turntable, and the error mapping relation does not change along with the gesture. However, in the actual three-dimensional space, the camera coordinate system is always attached to the turntable, and the change of the posture of the turntable means that the error coordinate system rotates, and the error cannot be unified back to the base coordinate system without performing inverse rotation compensation. The conventional method therefore suffers from a significant drop in control accuracy over a wide range of maneuvers or high pitch regions. 5. Control parameter dependent empirical tuning In the prior art, fast and slow loop division is realized in a mode of manually dividing bandwidth, but geometric consistency constraint is lacked, so that high-frequency compensation of the vibrating mirror is followed by a slow loop of a rotary table, the rotary table low-frequency correction interferes with the closed loop of the vibrating mirror, and oscillation or overshoot is easy to generate in the system. Therefore, a new control method is needed to build a unified three-dimensional line-of-sight geometric model, accurately map camera errors to a base coordinate system under any rotary table posture, process vibration mirrors and rotary table compensation under a unified frame at the same time, realize natural decoupling of fast and slow loops, and provide an error m