Semi-physical simulation gyro measurement simulation method for satellite attitude control system

Abstract

The invention discloses a semi-physical simulation gyro measurement simulation method for a satellite attitude control system, a compensation interface does not need to be added in gyro measurement simulation, and a frame angle of a three-axis turntable can directly correspond to a satellite attitude angle. The invention specifically relates to three aspects. The method comprises the following steps: (1) establishing a three-axis turntable motion equation according to a required attitude rotation sequence; and (2) calculating the angular velocity of the three-axis turntable frame according to the relative inertial angular velocity of the satellite. And (3) performing earth rotation angular velocity compensation calculation in the gyro measured value, and calculating and compensating earth rotation through software to obtain gyro output. According to the method provided by the invention, a hardware compensation interface does not need to be added in gyro measurement simulation, and the adaptability of a satellite semi-physical simulation system to different hardware equipment is improved. And a frame angle of the three-axis turntable can directly correspond to a satellite attitude angle, so that the simulation effect of the system on satellite attitude motion simulation is improved.

Description

Technical Field

[0001] The invention belongs to the field of satellite technology, and in particular relates to a semi-physical simulation gyro measurement simulation method for a satellite attitude control system. Background Art

[0002] Semi-physical simulation of satellite control systems is an effective means to verify the satellite control system scheme and performance, and is an important link in the development of satellite control systems. Gyro measurement is usually required in semi-physical simulation. A three-axis turntable is usually used to simulate the satellite attitude motion. The gyro is installed on the turntable and the angular velocity of the turntable is measured to simulate the gyro measurement of the satellite angular velocity. Therefore, it is necessary to drive the three-axis turntable to correctly simulate the satellite attitude motion. In addition, since the physical simulation is performed on the ground, the gyro measurement includes the angular velocity of the earth's rotation. This angular velocity does not exist in the actual satellite motion and needs to be deducted in the simulation.

[0003] The three-axis turntable method commonly used in semi-physical simulation can adopt the angular velocity drive method. The literature "Zhou Shengliang, Zhong Jinfeng, Gao Sihong, Implementation of turntable control algorithm in semi-physical simulation of satellite attitude control system [J], Electronic Products World, 2016, 23 (Z1): 61-63" solves the satellite relative inertial angular velocity according to the 2-1-3 rotation sequence to drive the outer, middle and inner frame angular velocities of the three-axis turntable. And the earth's rotation angular velocity is also solved to the frame angular velocity of the three-axis turntable for deduction. This method can make the gyro measurement value consistent with the satellite's relative inertial angular velocity, but the 2-1-3 rotation sequence is different from the commonly used satellite attitude definition method. The deduction of the earth's rotation angular velocity from the turntable frame angular velocity will also affect the turntable frame angle movement, making the turntable attitude angle inconsistent with the satellite attitude angle. The document "Liu Shenzhao, Semi-physical Simulation Method of Multi-Turntable Multi-Simulator for Satellite Control System [J], Aerospace Control, 2004.8: 73-77" solves the satellite relative inertial quaternion according to the 2-1-3 rotation sequence to drive the frame angle of the three-axis turntable. The compensation of the additional angular velocity of the gyro adopts current compensation, which requires the gyro to provide a contact point for compensation and add compensation current to the torque coil of the gyro. This method has requirements for the gyro interface, which not all gyros can meet. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a semi-physical simulation gyro measurement simulation method for a satellite attitude control system. In the gyro measurement simulation, there is no need to add a compensation interface, and the frame angle of the three-axis turntable can directly correspond to the satellite attitude angle. Specifically, there are three aspects. (1) According to the required attitude rotation sequence, the motion equation of the three-axis turntable is established. (2) According to the relative inertial angular velocity of the satellite, the frame angular velocity of the three-axis turntable is calculated. (3) The earth's rotation angular velocity compensation calculation is performed in the gyro measurement value, and the earth's rotation is compensated by software calculation to obtain the gyro output. The method proposed by the present invention does not need to add a hardware compensation interface in the gyro measurement simulation, thereby improving the adaptability of the satellite semi-physical simulation system to different hardware devices. In addition, the frame angle of the three-axis turntable can directly correspond to the satellite attitude angle, thereby improving the simulation effect of the system on the satellite attitude motion simulation.

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0006] Step 1: Define the three-axis turntable frame angle and rotation order, and establish the motion equation;

[0007] According to the required posture rotation sequence, define the inner, middle and outer three-axis frame angles and rotation sequence of the three-axis turntable, and establish the motion equation of the three-axis turntable;

[0008] Step 2: Calculate the angular velocity of the three-axis turntable frame;

[0009] According to the satellite's relative inertial angular velocity, the angular velocities of the inner, middle and outer three-axis frames of the three-axis turntable are calculated so that the angular velocity of the inner frame of the three-axis turntable is consistent with the satellite's relative inertial angular velocity.

[0010] Step 3: Calculate the compensation of the earth's rotation angular velocity;

[0011] The angular velocity compensation calculation of the earth's rotation is performed in the gyro measurement value, and the earth's rotation is compensated by software calculation to obtain the gyro output.

[0012] Furthermore, the step 1 is specifically as follows:

[0013] The turntable base coordinate system is denoted as O d X d Y d Z d , the direction of the rotation axis is consistent with that when the frame angles of the three-axis turntable are all zero; Z d X is the axis of the turntable frame. d Y is the axis of the turntable middle frame. d It is the inner frame axis of the turntable;

[0014] Assume that the three-axis turntable is around the outer frame Z d The frame rotation angle is γ, around the middle frame X d Rotate the frame angle β around the inner frame Y dThe rotation frame angle is -α; the turntable base coordinate system to the turntable inner frame attitude transformation matrix is:

[0015]

[0016] Assume that the angular velocity of the earth in the turntable base coordinate system is vector ω d , the angular velocity of the turntable inner frame is:

[0017]

[0018] Furthermore, the step 2 is specifically as follows:

[0019] Assume that the attitude angles of the inertial coordinate system to the satellite body coordinate system are ψ, θ, the transformation matrix from the inertial coordinate system to the satellite body coordinate system is:

[0020]

[0021] The relative inertial angular velocity vector of the satellite body is:

[0022]

[0023] The relationship between the angular velocity of the three-axis turntable frame and the angular velocity of the satellite is set as:

[0024]

[0025] Among them, ω bix ,ω biy ,ω biz are the three components of the satellite body's relative inertial angular velocity vector.

[0026] Furthermore, the step 3 is specifically as follows:

[0027] Install the gyro inside the turntable frame, and assume that the conversion matrix between the gyro and the turntable frame is E gy_zt , the angular velocity measured by the gyroscope is:

[0028] ω gy =E gy_zt ω zt (6)

[0029] After compensating for the Earth's rotational velocity, the gyro measurement is:

[0030] ω′ gy =ω gy -E gy_zt E b_i ω d (7)

[0031] From this, the angular velocity of the turntable measured by the gyro after compensation can be obtained:

[0032]

[0033] This angular velocity is the angular velocity of the satellite body measured by the semi-physical simulation system simulating the gyroscope.

[0034] The beneficial effects of the present invention are as follows:

[0035] The present invention decomposes the satellite relative inertial angular velocity into the three-axis turntable frame angular velocity according to the 3-1-2 rotation sequence, drives the turntable frame angular velocity, and calculates the gyro output by compensating the earth's rotation angular velocity through software. The main effects are as follows:

[0036] (1) The 3-1-2 rotation sequence is consistent with the commonly used satellite attitude description method. The three-axis turntable frame angle can directly correspond to the satellite attitude angle.

[0037] (2) The software compensates for the angular velocity caused by the rotation of the earth and simulates the gyro measurement output. The gyro does not need to add a compensation interface and does not affect the angular velocity of the three-axis turntable frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the coordinate system of the three-axis turntable and the turntable base of the present invention.

[0039] Figure 2 It is the relative inertial angular velocity curve of the satellite body in the embodiment of the present invention.

[0040] Figure 3 This is the angular velocity curve of the gyro measurement turntable after earth speed compensation in the embodiment of the present invention.

[0041] Figure 4 It is the relative inertial attitude angle curve of the satellite body in the embodiment of the present invention.

[0042] Figure 5 It is the frame angle curve of the three-axis turntable in the embodiment of the present invention. DETAILED DESCRIPTION

[0043] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0044] The existing simulation methods of gyro measurement in satellite semi-physical simulation mostly use a 2-1-3 rotation sequence to solve the satellite attitude angle or angular velocity to obtain the frame angle or angular velocity of the three-axis turntable. This rotation sequence is easy to implement for the three-axis turntable, but it is inconsistent with the 3-1-2 attitude description commonly used in satellite attitude description, and cannot be directly linked to the satellite attitude angle. Compensation for the angular velocity of the earth's rotation can be deducted from the frame angular velocity of the three-axis turntable, but it will affect the movement of the frame angle. Or compensation is performed in gyro measurement, and the gyro needs to provide a compensation interface. The present invention proposes a method for driving the frame angular velocity of the turntable in a 3-1-2 rotation sequence, and a method for software compensation of the gyro output. There is no need to add a compensation interface in the gyro measurement simulation, and the frame angle of the three-axis turntable can directly correspond to the satellite attitude angle.

[0045] Step 1: Define the three-axis turntable frame angle and rotation sequence, and establish the motion equation.

[0046] According to the required posture rotation sequence, the inner, middle and outer frame angles and rotation sequence of the three-axis turntable are defined, and the motion equation of the three-axis turntable is established.

[0047] Define the turntable coordinate system according to the required posture rotation sequence, such as the 3-1-2 rotation sequence. The turntable base coordinate system is denoted as O d X d Y d Z d , which is consistent with the rotation axis direction when the three-axis turntable frame angle is zero. d X is the axis of the turntable frame. d Y is the axis of the turntable middle frame. d is the inner frame axis of the turntable. The coordinate system of the three-axis turntable and the turntable base is as follows Figure 1 Shown

[0048] Assume that the three-axis turntable is around the outer frame Z d The frame rotation angle is γ, around the middle frame X d Rotate the frame angle β around the inner frame Y d The rotation frame angle is -α (because the turntable itself rotates around -Y d Rotation, where the rotation angle introduces a negative sign). The turntable base coordinate system to the turntable inner frame attitude transformation matrix is:

[0049]

[0050] Assume that the angular velocity of the earth in the turntable base coordinate system is vector ω d , the angular velocity of the turntable inner frame is:

[0051]

[0052] Step 2: Calculate the angular velocity of the three-axis turntable frame.

[0053] According to the satellite's relative inertial angular velocity, the angular velocities of the inner, middle and outer three-axis frames of the three-axis turntable are calculated so that the angular velocity of the inner frame of the three-axis turntable is consistent with the satellite's relative inertial angular velocity.

[0054] Assume that the attitude angles of the inertial coordinate system to the satellite body coordinate system are ψ, θ, the transformation matrix from the inertial coordinate system to the satellite body coordinate system is:

[0055]

[0056] The relative inertial angular velocity vector of the satellite body is:

[0057]

[0058] The relationship between the angular velocity of the three-axis turntable frame and the angular velocity of the satellite is set as:

[0059]

[0060] Among them, ω bix ,ω biy ,ω biz are the three components of the satellite body's relative inertial angular velocity vector.

[0061] Step 3: Calculate the earth's rotation angular velocity compensation.

[0062] The angular velocity compensation calculation of the earth's rotation is performed in the gyro measurement value, and the earth's rotation is compensated by software calculation to obtain the gyro output.

[0063] Install the gyro inside the turntable frame, and assume that the conversion matrix between the gyro and the turntable frame is E gy_zt , the angular velocity measured by the gyroscope is:

[0064] ω gy =E gy_zt ω zt (6)

[0065] After compensating for the Earth's rotational velocity, the gyro measurement is:

[0066] ω′ gy =ω gy -E gy_zt E b_i ω d (7)

[0067] From this, the angular velocity of the turntable measured by the gyro after compensation can be obtained:

[0068]

[0069] This angular velocity is the angular velocity of the satellite body measured by the semi-physical simulation system simulating the gyroscope.

[0070] Example:

[0071] This embodiment is a semi-physical simulation of the process of a satellite moving from a certain initial attitude to the sun orientation, and the gyroscope is installed on the inner frame of the three-axis turntable.

[0072] Step 1: Establish the motion equation of the three-axis turntable.

[0073] In this embodiment, the coordinate system of the three-axis turntable and the turntable base is as follows: Figure 1 As shown. The vector of the earth's angular velocity in the turntable base coordinate system is:

[0074]

[0075] The angular velocity of the inner frame of the turntable is as shown in formula (2).

[0076] Step 2: Calculate the angular velocity of the three-axis turntable frame.

[0077] The calculation method of the angular velocity of the three-axis turntable frame is shown in formula (5).

[0078] Step 3: Calculation of compensation for the earth's rotation angular velocity.

[0079] The compensation of the earth's rotation angular velocity is calculated according to formula (7). In this embodiment, the conversion matrix between the gyro and the inner frame of the turntable is:

[0080]

[0081] During the semi-physical simulation, the dynamic model calculates the satellite's relative inertial angular velocity as Figure 2 After compensating for the angular velocity of the earth's rotation, the angular velocity of the turntable measured by the gyro is Figure 3 After compensation, the gyro measurement is consistent with the satellite angular velocity, and the angular velocity error in the attitude stabilization stage is less than 0.001° / s, which can better simulate the gyro's measurement of the satellite's angular velocity.

[0082] The dynamic model calculates the satellite's relative inertial attitude angle as follows: Figure 4 , the three-axis turntable frame angle is Figure 5 The frame angle of the three-axis turntable is consistent with the satellite attitude angle, where the outer frame angle γ is consistent with the satellite attitude angle ψ, and the middle frame angle β is consistent with the satellite attitude angle The inner frame angle -α is consistent with the satellite attitude angle θ. The angle error in the attitude stabilization stage is less than 0.01°, which can better simulate the satellite attitude angle.

Claims

1. A semi-physical simulation method for gyro measurement of a satellite attitude control system, characterized in that: The steps include: Step 1: Define the three-axis turntable frame angle and rotation order, and establish the motion equation; According to the required posture rotation sequence, define the inner, middle and outer three-axis frame angles and rotation sequence of the three-axis turntable, and establish the motion equation of the three-axis turntable; Step 2: Calculate the angular velocity of the three-axis turntable frame; According to the satellite's relative inertial angular velocity, the angular velocities of the inner, middle and outer three-axis frames of the three-axis turntable are calculated so that the angular velocity of the inner frame of the three-axis turntable is consistent with the satellite's relative inertial angular velocity; Step 3: Calculate the compensation of the earth's rotation angular velocity; The angular velocity compensation calculation of the earth's rotation is performed in the gyro measurement value, and the earth's rotation is compensated by software calculation to obtain the gyro output.

2. A semi-physical simulation gyro measurement simulation method for a satellite attitude control system according to claim 1, characterized in that: The step 1 is specifically as follows: The turntable base coordinate system is denoted as O d X d Y d Z d , the direction of the rotation axis is consistent with that when the frame angles of the three-axis turntable are all zero; Z d X is the axis of the turntable frame. d Y is the axis of the turntable middle frame. d It is the inner frame axis of the turntable; Assume that the three-axis turntable is around the outer frame Z d The frame rotation angle is γ, around the middle frame X d Rotate the frame angle β around the inner frame Y d The rotation frame angle is -α; the turntable base coordinate system to the turntable inner frame attitude transformation matrix is: Assume that the angular velocity of the earth in the turntable base coordinate system is vector ω d , the angular velocity of the turntable inner frame is:

3. The semi-physical simulation gyro measurement simulation method of a satellite attitude control system according to claim 2 is characterized in that: The step 2 is specifically as follows: Assume that the attitude angles of the inertial coordinate system to the satellite body coordinate system are ψ, θ, the transformation matrix from the inertial coordinate system to the satellite body coordinate system is: The relative inertial angular velocity vector of the satellite body is: The relationship between the angular velocity of the three-axis turntable frame and the angular velocity of the satellite is set as: Among them, ω bix ,ω biy ,ω biz are the three components of the satellite body's relative inertial angular velocity vector.

4. The semi-physical simulation gyro measurement simulation method of a satellite attitude control system according to claim 3 is characterized in that: The step 3 is as follows: Install the gyro inside the turntable frame, and assume that the conversion matrix between the gyro and the turntable frame is E gy_zt , the angular velocity measured by the gyroscope is: oh gy =E gy_zt oh zt (6) After compensating for the Earth's rotational velocity, the gyro measurement is: oh' gy =ω gy -E gy_zt E b_i oh d (7) From this, the angular velocity of the turntable measured by the gyro after compensation can be obtained: This angular velocity is the angular velocity of the satellite body measured by the semi-physical simulation system simulating the gyroscope.

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