CN106843249B - two-dimensional guiding attitude control method - Google Patents

Abstract

The invention discloses a high-precision high-stability two-dimensional guidance attitude control method, which comprises the following processes: the angular velocity instruction of two-dimensional guidance is added in a correction loop in the original general non-guidance attitude control method, which is equivalent to angular velocity feedforward of a system, so that the response capability of the system can be improved, and rapid guidance control is realized; and decoupling control is carried out on the yaw in the rolling direction, so that the coupling influence on the rolling direction after the yaw direction is guided is eliminated. By the measures, the rapid two-dimensional guidance access control of any position of the satellite can be realized, and the control precision of the system can be improved. The invention has the advantages of simple and easy on-board implementation and ground operation.

Description

Two-dimensional guiding attitude control method

Technical Field

the invention belongs to the technical field of satellite attitude control, and particularly relates to a high-precision high-stability two-dimensional guidance attitude control method.

Background

In the application of the satellite-borne synthetic aperture radar, the Doppler characteristic has direct influence on the azimuth resolution, the calculation of the pulse repetition frequency, the ambiguity problem of the azimuth direction and the imaging precision. The mismatch of the doppler center frequency of the SAR echo can even result in an inability to image when it is severe. The change of the Doppler center frequency caused by the influence of the earth rotation generates the range migration, which brings difficulty to the imaging processing.

In order to eliminate the influence of Doppler central frequency drift on radar imaging, a radar satellite originally designs a simple one-dimensional yaw guidance scheme, which can only start to switch on or stop guidance near a guidance angle of 90 degrees or 270 degrees, wherein the guidance angle is zero, and the deviation of guidance has a coupling influence of about 0.02 degrees in the rolling direction.

With the improvement of imaging precision requirements, a two-dimensional guidance scheme is gradually designed, namely guidance control is respectively carried out along the pitching direction and the yawing direction, the attitude control precision and the stability are equivalent to those of guidance not carried out, and the two-dimensional guidance can be quickly accessed in any direction, but the guidance can not be started only near the guidance angle of 90 degrees or 270 degrees at the latitude argument.

disclosure of Invention

The invention aims to provide a two-dimensional guiding attitude control method, which is characterized in that a satellite is stably controlled through a three-axis to ensure that a satellite coordinate system of the satellite is superposed relative to an orbit coordinate system, and the satellite tracks the motion of the orbit coordinate system to realize the stable earth orientation of the satellite; and through two-dimensional guidance control, the Doppler center frequency drift phenomenon is eliminated, and the purposes of quick access to two-dimensional guidance and two-dimensional guidance access control can be achieved under the condition that the precision and the stability of the system are not influenced and the satellite is in any position.

In order to achieve the above purpose, the invention is realized by the following technical scheme:

A two-dimensional guiding attitude control method comprises the following processes:

Introducing a yaw guide angle and a yaw guide angular speed in the yaw direction of the satellite operation, and calculating to obtain a corrected yaw angular speed;

Decoupling control is carried out in the rolling direction of satellite operation and the yaw direction, and the decoupling control is used for eliminating the coupling influence on the rolling direction after the yaw direction is guided, so that the corrected rolling angular speed is obtained;

Introducing a pitching guide angle and a pitching guide angle speed in the pitching direction of the satellite operation, and calculating to obtain a corrected pitching angle speed;

Adding the corrected yaw angular velocity, the corrected pitch angular velocity and the corrected rolling angular velocity respectively and correspondingly with the combined output angular velocity of the fiber-optic gyroscope to obtain an angular velocity instruction;

and substituting the angular speed instruction into a control algorithm to obtain the control moment of the satellite flywheel.

preferably, the corrected yaw rate ω is_kxand the corrected roll angular velocity ω_kzComprises the following steps:

Wherein the parameter K, K_intin order to be the gain factor,Psi is the roll and yaw attitude angle, omega, respectively₀For track angular velocity, #_c、Respectively yaw guide angle and yaw guide angular velocity.

Preferably, said corrected pitch angle velocity ω_kycomprises the following steps:

In the formula, parameter K_Icy、K_cyIs a gain coefficient, theta is a pitch attitude angle, theta_c、respectively, a pitch direction guide angle and a guide angular velocity.

Preferably, the angular velocity command signal ω of the control torque for controlling the satellite flywheel_cx、ω_cy、ω_czthe calculation is as follows:

ω_cx＝ω_kx+ω_gx

ω_cy＝ω_ky+ω_gy

ω_cz＝ω_kz+ω_gz

In the formula, ω_gx、ω_gy、ω_gzAnd outputting an angular velocity signal for the gyro combination.

compared with the prior art, the invention has the following advantages:

1) The high-precision high-stability two-dimensional guidance control is realized, in the control process, guidance angle and guidance angle speed instructions are added in the yaw direction and the pitch direction, the rapid access of any position of the two-dimensional guidance is realized, the track coupling influence in the yaw direction is compensated in the rolling direction, and the control precision and the stability are improved.

2) The invention is easy to realize on-satellite and ground operation, can realize the fast two-dimensional guidance access control of the satellite at any position, and can improve the control precision of the system.

Drawings

Fig. 1 is a flowchart of a two-dimensional guiding attitude control method according to the present invention.

Detailed Description

The present invention will now be further described by way of the following detailed description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings.

As shown in fig. 1, the two-dimensional guiding attitude control method of the present invention includes the following steps:

Adding a yaw guide angle and a yaw guide angular speed instruction into the yaw direction correction loop; namely, a two-dimensional guiding angular velocity instruction is added into a correction loop in the original general non-guiding attitude control method, and the two-dimensional guiding angular velocity instruction is equivalent to angular velocity feedforward of a satellite attitude control system, so that the response capability of the satellite attitude control system can be improved, and rapid guiding control can be realized. The correction loop is used for generating the command angular velocity and the two-dimensional guidance command angular velocity of the satellite body coordinate system tracking orbit coordinate system. By searching for the satellite attitude motion law, Doppler center frequency offset is compensated, and a simplified representation mode of a yaw guide angle and a pitch guide angle can be obtained:

yaw lead angle psi_c：

Yaw vectoring angular velocityis composed of

in the formulai is the track inclination angle and u is the latitude argument;ω₀Is the satellite on-orbit real-time angular velocity, omega_eis the rotational angular velocity of the earth.

Pitch guide angle theta_c：

Angular velocity of pitch guidance

In the formula: e is track eccentricity, f is true paraxial point angle, T_sIs a control cycle.

and the yaw direction realizes the control of two-dimensional guidance by adding a guidance angle and a guidance angular speed instruction. And decoupling control with yaw is carried out in the rolling direction of satellite operation, and coupling influence on the rolling direction after the yaw direction is guided is eliminated.

I.e. yaw rate omega_kxAnd roll angular velocity omega_kzthe correction loop algorithm is as follows:

Wherein the parameter K, K_intIn order to be the gain factor,Psi is the calculated roll and yaw attitude angle, ω₀For track angular velocity, #_c、Respectively yaw guide angle and yaw guide angular velocity.

And the control of two-dimensional guidance is realized by adding a guidance angle and a guidance angular speed instruction in the pitching direction.

Corrected pitch angular velocity ω_kyThe following were used:

in the formula, parameter K_Icy、K_cyIs a gain coefficient, theta is a calculated pitch attitude angle, omega₀Is the angular velocity of the track, theta_c、pitch guide angle and pitch guide angular velocity, respectively.

After the corrected angular velocities of the three channels in the pitching direction, the yawing direction and the rolling direction are obtained, the corrected angular velocities are added into a stable loop, so that the satellite can move according to the rule of the corrected angular velocities, the satellite orbit coordinate system is tracked to move, and the aim of three-axis ground orientation is fulfilled.

And the angular velocity of the input stabilization loop isLet signal omega_cx、ω_cy、ω_czFor correcting angular velocity omega_kx、ω_ky、ω_kzoutput angular velocity signal omega combined with gyroscope_gx、ω_gy、ω_gzSum, so that the angular velocity command signal ω is calculated_cx、ω_cy、ω_cz，

The calculation is as follows:

ω_cx＝ω_kx+ω_gx (8)

ω_cy＝ω_ky+ω_gy (9)

ω_cz＝ω_kz+ω_gz (10)

ω_gx、ω_gy、ω_gzAnd outputting an angular velocity signal for the gyro combination.

The above angular velocity command signal ω_cx、ω_cy、ω_czSubstituting the control algorithm to obtain the control moment instruction of the satellite flywheel.

by the above measures, the fast two-dimensional guidance access control at any position can be realized, and the control precision of the system can be improved.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.

Claims (4)

1. A two-dimensional guiding attitude control method is characterized by comprising the following processes:

Introducing a yaw guide angle and a yaw guide angular speed in the yaw direction of the satellite operation, and calculating to obtain a corrected yaw angular speed;

Decoupling control is carried out in the rolling direction of satellite operation and the yaw direction, and the decoupling control is used for eliminating the coupling influence on the rolling direction after the yaw direction is guided, so that the corrected rolling angular speed is obtained;

Introducing a pitching guide angle and a pitching guide angle speed in the pitching direction of the satellite operation, and calculating to obtain a corrected pitching angle speed;

adding the corrected yaw angular velocity, the corrected pitch angular velocity and the corrected rolling angular velocity respectively and correspondingly with the combined output angular velocity of the fiber-optic gyroscope to obtain an angular velocity instruction;

and substituting the angular speed instruction into a control algorithm to obtain the control moment of the satellite flywheel.

2. A two-dimensional guidance attitude control method according to claim 1, characterized in that: the corrected yaw rate ω_kxAnd the corrected roll angular velocity ω_kzComprises the following steps:

Wherein the parameter K, K_intin order to be the gain factor,Psi is the roll and yaw attitude angle, omega, respectively₀For track angular velocity, #_c、Respectively yaw guide angle and yaw guide angular velocity.

3. A two-dimensional guidance attitude control method according to claim 2, characterized in that: the corrected pitch angular velocity ω_kyComprises the following steps:

in the formula, parameter K_Icy、K_cyis a gain coefficient, theta is a pitch attitude angle, theta_c、Pitch guide angle and pitch guide angular velocity, respectively.

4. A two-dimensional steering attitude control method according to claim 3, wherein said angular velocity command signal ω for controlling the control torque of the satellite flywheel_cx、ω_cy、ω_czThe calculation is as follows:

ω_cx＝ω_kx+ω_gx

ω_cy＝ω_ky+ω_gy

ω_cz＝ω_kz+ω_gz

In the formula, ω_gx、ω_gy、ω_gzAnd outputting an angular velocity signal for the gyro combination.