Satellite attitude safe capture control method based on magnetic measurement and magnetic control

Abstract

A satellite attitude safe capture control method based on magnetic measurement and magnetic control is provided. In the case of gyro failure or jet unavailability, an angular velocity estimation algorithm relying on magnetometer measurement is designed, and a rate damping and sun orientation control algorithm using only a magnetic torque device as an actuator is designed, so that the satellite safety is ensured in the case of gyro failure or jet unavailability.

Description

Technical Field

[0001] This invention relates to a satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control, belonging to the field of spacecraft control technology. Background Technology

[0002] With the increasing diversification of space missions and the need for cost control, microsatellites (picosatellites / nanosatellites) have been widely used due to their outstanding characteristics such as small size, light weight, low cost, powerful functions, short development time, strong survivability and maneuverability, and flexible launch methods. Typically, picosatellites and nanosatellites are launched via a piggyback launch method, which cannot guarantee orbital insertion conditions. The significant interference caused by separation from the launch vehicle leads to highly complex initial attitude changes. Because they lack jet propulsion, fully utilizing the Earth's magnetic field for attitude magnetic control has become the primary choice for picosatellites and nanosatellites. In fact, since the early days of the space age, people have paid extensive attention to attitude magnetic control methods for spacecraft, especially after the emergence of picosatellites and nanosatellites, the demand for pure magnetic control has become even stronger. Without gravity gradient rods, rotation mechanisms, and jet systems, using only magnetic torquers to adjust the satellite's attitude ultimately results in a simpler satellite structure, lower cost, and higher reliability.

[0003] Safe satellite capture is a necessary measure to ensure the overall safety of the satellite in the event of system failure or other anomalies. Conventional satellite safe capture methods use gyroscopes to measure angular velocity, jet control for rate damping, sun search, sun orientation, and Earth capture. These capture methods cannot guarantee satellite safety when gyroscopes fail or jets are unavailable, and are also unsuitable for microsatellites that are not equipped with gyroscopes and thrusters. Summary of the Invention

[0004] This invention proposes a satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control. In the event of gyroscope failure or jet unavailability, this method designs an angular velocity estimation algorithm based on magnetometer measurement, as well as a rate damping and sun-oriented control algorithm that uses only a magnetic torque generator as the actuator, thus ensuring satellite safety in the event of gyroscope failure or jet unavailability.

[0005] The technical solution of this invention is: a satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control, comprising the following steps:

[0006] Step 1: Run the magnetic spin sub-mode, use the magnetometer to filter and estimate the satellite's attitude angular velocity, use the magnetic torque generator to control the satellite's attitude angular velocity to the predetermined angular velocity, and autonomously switch to the magnetic sun orientation sub-mode;

[0007] Step 2: Run the magnetic solar orientation sub-mode to continue providing the magnetic moment required for satellite spin orientation, and use the solar sensor to measure the direction of the solar vector, and use the magnetic torque meter to precess the satellite spin axis towards the solar direction;

[0008] Step 3: After receiving ground commands, the satellite despins through magnetic damping and then autonomously switches to magnetic Earth orientation sub-mode. It uses a star sensor for attitude determination without a gyroscope, determines the satellite's attitude using the star sensor, and achieves stable three-axis Earth orientation through magnetic torque control.

[0009] Preferably, in the magnetic spinner mode, the satellite attitude angular velocity estimation includes:

[0010] One-step prediction:

[0011] ω k,k-1 =ω k-1 +T c ′Δt

[0012] New interest calculation:

[0013]

[0014] Filter correction:

[0015] ω k =ω k,k-1 +K(z-ω k,k-1 )

[0016] Among them, T c 'This is the control torque value calculated based on the control quantity of the previous cycle; and It is the unit vector of the magnetic field direction in the current and previous periods, K is the filter correction coefficient, and ω k ω k-1 Δt represents the estimated angular velocity values ​​for the current and previous cycles, where Δt is the sampling period.

[0017] Preferably, in the magnetic spinon mode, the estimated angular velocity ω is utilized. k Magnetic moment control enables rate damping of the satellite, allowing it to spin at a specified angular velocity, with magnetic torque T. c The calculation formula is

[0018]

[0019] in, K represents the difference multiplication operation. MMdamp For adjustable control gain, ω ref The nominal angular velocity of spin. It is the unit vector of the magnetic field direction for this period.

[0020] Preferably, in the magnetic sun-orienting sub-mode, the data is first determined based on digital sun measurements, the desired angular velocity of sun rotation, and... Obtain the magnetic moment variable M pre Then, using the assignment formula M = M + Kpre ·M pre The magnetic moment M is calculated, and the final formula for calculating the control magnetic moment is as follows:

[0021] Among them, K pre For adjustable control gain, the initial value of the magnetic moment M in the magnetic sun-oriented sub-mode is 0.

[0022] Preferably, the magnetic capture and Earth orientation stage is divided into a magnetic damping sub-mode and a magnetic Earth orientation sub-mode. In the magnetic damping sub-mode, the satellite's rate damping is achieved by using star-sensor measurement and magnetic moment control to achieve satellite despinning. In the magnetic Earth orientation sub-mode, the satellite uses a star sensor to determine its attitude and uses a magnetic torque controller to achieve a three-axis stable Earth orientation attitude.

[0023] Preferably, in the magnetic damping sub-mode, the satellite's three-axis angular velocity signals are provided by star-sensor measurements, and the target angular velocity is set to zero to achieve satellite despinning.

[0024] Preferably, in the magnetic-to-ground orientation sub-mode, the satellite uses a star sensor to determine its attitude. and angular velocity The satellite's three-axis stable Earth-orientation attitude is achieved through magnetic torque control, with the magnetic torque T... c The calculation formula is

[0025]

[0026] Magnetic moment

[0027] Among them, K pMM With K dMM All are adjustable control gains. Φ ref and These are the reference attitude angle and angular velocity, respectively.

[0028] A satellite attitude safety acquisition and control system based on magnetic measurement and magnetic control includes:

[0029] The magnetic spin module operates in magnetic spin sub-mode, using a magnetometer to filter and estimate the satellite's attitude angular velocity. It then uses a magnetic torque converter to control the satellite's attitude angular velocity to a predetermined value before autonomously switching to magnetic sun-alignment sub-mode.

[0030] The magnetic sun orientation module runs the magnetic sun orientation sub-mode, continues to provide the magnetic moment required for satellite spin orientation, and uses a sun sensor to measure the direction of the sun vector, and uses a magnetic torque device to precess the satellite spin axis toward the sun.

[0031] After receiving ground commands, the magnetic ground acquisition module autonomously switches to the magnetic ground orientation sub-mode after de-spinning the satellite through magnetic damping. It then uses a star sensor for attitude determination without a gyroscope, determines the satellite's attitude using the star sensor, and achieves three-axis stable Earth orientation through magnetic torque control.

[0032] A computer-readable storage medium storing a computer program, characterized in that, when executed by a processor, the computer program implements the steps of a satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control.

[0033] A computer software product includes: a processor and a storage device;

[0034] Storage device for storing one or more programs.

[0035] When the one or more programs are executed by one or more processors, the one or more processors implement the satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] (1) The satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control proposed in this invention is a new type of satellite attitude control strategy, which effectively solves the contradiction between on-board gyroscope / jet failure or the need to avoid using jet control as much as possible for the sake of saving fuel.

[0038] (2) Compared with existing technologies, the technical method adopted in this invention fully utilizes the measurement characteristics of low magnetometers and the control characteristics of magnetic torquers. Through the design of angular velocity filtering algorithm and magnetic control allocation algorithm, the problem of safe acquisition of satellite attitude is cleverly solved. The entire algorithm design is simple and the workload of parameter debugging is small.

[0039] (3) This invention proposes a new solution for the safe acquisition control of low-low tracking gravity satellites. It does not require additional data input, is simple to calculate, and can be adapted to a large class of military and civilian satellite systems with similar control requirements. It has strong engineering practicality.

[0040] (4) The present invention designs an angular velocity estimation algorithm based on magnetometer measurement, and a rate damping and solar orientation control algorithm using only a magnetic torque device as the actuator, which ensures satellite safety in the event of gyroscope failure or jet unavailability. Attached Figure Description

[0041] Figure 1 This is a schematic diagram illustrating the relative positions of satellites before the interstellar spacing maintenance technology was implemented.

[0042] Figure 2This is the satellite sub-mode variation curve.

[0043] Figure 3 This is the actual attitude angle curve of the satellite.

[0044] Figure 4 This is the actual attitude angular velocity curve of the satellite.

[0045] Figure 5 The curve representing the angle between the sun and the -Z axis. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0047] This invention addresses the requirements of novel satellite attitude safety acquisition missions based on magnetic measurement and magnetic control. It proposes a magnetic rate damping method and a magnetic sun-to-sun / sun-to-ground orientation method, designs an online angular velocity prediction method relying solely on magnetometer measurements, and provides a magnetic damping control law and a sun-to-ground / earth-to-ground orientation control law for pure magnetic control. This provides a reliable, effective, and fuel-efficient novel approach to satellite attitude safety acquisition.

[0048] This invention relates to a satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control, comprising the following steps:

[0049] Step 1: Use a magnetometer to measure and estimate the angular velocity to achieve spin damping;

[0050] By utilizing magnetometer measurements and magnetic moment control, the satellite's spin damping is achieved, controlling its three-axis angular velocities to near predetermined levels, thus realizing the satellite's spin orientation. An estimated value of the satellite's angular velocity is obtained through a magnetometer-based angular velocity filtering estimation method, providing a basis for judgment during the transition to the sun-orientation phase and for ground-based interpretation.

[0051] A Kalman filter is designed based on the dynamic equations and magnetometer measurements. The angular velocity estimation algorithm based on magnetometer measurements is as follows:

[0052] One-step prediction:

[0053] ω k,k-1 =ω k-1 +T c ′Δt

[0054] New interest calculation:

[0055]

[0056] Filter correction:

[0057] ω k =ω k,k-1 +K(z-ω k,k-1)

[0058] Where T c 'This is the control torque value calculated based on the control quantity of the previous cycle.' and It is the unit vector of the magnetic field direction in the current and previous periods, K is the filter correction coefficient, and ω k This is the estimated angular velocity for this period.

[0059] In the magnetic spin sub-mode, the satellite's spin is controlled by magnetic moment control, bringing its three-axis angular velocities close to predetermined values ​​to achieve spin orientation. The control law used is similar to the Bdot control law, but unlike the Bdot law, an estimated satellite angular velocity is obtained through a magnetometer-based angular velocity filtering estimation method. This provides a basis for transitioning to the sun-oriented phase and for ground-based interpretation. The estimated angular velocity ω is then used... k Magnetic moment control enables rate damping of the satellite, which operates in spin mode, causing the satellite to spin along a specified axis of rotation and at a specified angular velocity. The magnetic torque T... c The calculation formula is

[0060]

[0061] in, K represents the difference multiplication operation. MMdamp For adjustable control gain, ω ref This is the nominal angular velocity of the spin.

[0062] Step 2: Achieve satellite spin orientation to the sun based on magnetometer and solar sensor;

[0063] In the magnetic sun-orientation sub-mode, in addition to continuing to provide the magnetic moment required for satellite spin orientation, the direction of the solar vector is measured using a solar sensor. The precession torque generated by the magnetic moment causes the satellite spin axis to precess in the direction of the sun, thus achieving the satellite's sun-orientation state.

[0064] Based on digital solar measurements, the expected angular velocity of solar rotation, and... Obtain the magnetic moment variable M pre Its specific expression needs to be determined based on the installation of the sun axis and digital sun; the calculation formula for the control magnetic moment is further obtained as follows:

[0065]

[0066] M = M + K pre ·M pre

[0067] Among them, K pre The magnetic moment M is initially set to 0, which is an adjustable control gain.

[0068] Step 3: Implementation of the magnetic-to-ground capture strategy.

[0069] Once the ground has completed troubleshooting and repair of the satellite malfunction, it can issue a command to allow the satellite to enter the magnetic acquisition and Earth orientation phase and establish an Earth orientation attitude.

[0070] The magnetic capture-to-ground orientation phase is divided into a magnetic damping sub-mode and a magnetic-to-ground orientation sub-mode. The difference between the magnetic damping sub-mode and the magnetic spin sub-mode is that the angular velocity signal in the magnetic-to-ground capture sub-mode is provided by star-sensor measurement, and the target angular velocity is set to zero to achieve satellite despinning. In magnetic-to-ground orientation...

[0071] In sub-mode, the satellite uses a star sensor to determine its attitude. and angular velocity The satellite's three-axis stable Earth-orientation attitude is achieved through magnetic torque control, with the magnetic torque T... c The calculation formula is

[0072]

[0073] Among them, K pMM With K dMM All are adjustable control gains. Φ ref and These are the reference attitude angle and angular velocity, respectively.

[0074] This invention also provides a satellite attitude safety acquisition and control system based on magnetic measurement and magnetic control, comprising:

[0075] The magnetic spin module operates in magnetic spin sub-mode, using a magnetometer to filter and estimate the satellite's attitude angular velocity. It then uses a magnetic torque converter to control the satellite's attitude angular velocity to a predetermined value before autonomously switching to magnetic sun-alignment sub-mode.

[0076] The magnetic sun orientation module runs the magnetic sun orientation sub-mode, continues to provide the magnetic moment required for satellite spin orientation, and uses a sun sensor to measure the direction of the sun vector, and uses a magnetic torque device to precess the satellite spin axis toward the sun.

[0077] After receiving ground commands, the magnetic ground acquisition module autonomously switches to the magnetic ground orientation sub-mode after de-spinning the satellite through magnetic damping. It then uses a star sensor for attitude determination without a gyroscope, determines the satellite's attitude using the star sensor, and achieves three-axis stable Earth orientation through magnetic torque control.

[0078] The implementation of the relevant functions in the system can be found in the description of the methods mentioned above.

[0079] The present invention further provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control.

[0080] The present invention further provides a computer software product, comprising: a processor and a storage device;

[0081] Storage device for storing one or more programs.

[0082] When the one or more programs are executed by one or more processors, the one or more processors implement a satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control.

[0083] Example:

[0084] Taking the XX-4 satellite B as an example, a simulation verification of the satellite attitude safety acquisition control method based on magnetic measurement and magnetic control was conducted. The magnetic acquisition mode is divided into four sub-modes. The magnetic spin sub-mode (SubMode=0) uses magnetometer filtering to determine the satellite's attitude angular velocity, and uses a magnetic torquer to control the satellite's attitude angular velocity to near the target angular velocity (roll 0, pitch 0, yaw -0.5° / s). It then autonomously switches to the magnetic sun orientation sub-mode (SubMode=1), using a sun sensor to determine the sun's position within the system, and using a magnetic torquer to precess the satellite's spin axis towards the sun. After receiving ground commands, the satellite enters the magnetic earth-orientation acquisition phase. First, magnetic damping is used to de-rotate the satellite's attitude angular velocity to near zero (SubMode=2), then it autonomously switches to the magnetic earth-orientation sub-mode (SubMode=3), using star-sensor gyroscope-less attitude determination, and using a pure magnetic control algorithm for magnetic earth-orientation acquisition to converge the satellite's three-axis attitude angles and angular velocities to a three-axis stable earth-orientation state. Submodes, attitude variations, and the curves showing the angle between the -z axis and the Sun for star B are shown below. Figures 2-5 .

[0085] The simulation results show that the satellite can successfully complete the control objectives of each stage of magnetic acquisition and ultimately establish a stable operating state with respect to Earth.

[0086] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0087] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control, characterized in that... Includes the following steps: Step 1: Run the magnetic spin sub-mode, use the magnetometer to filter and estimate the satellite's attitude angular velocity, use the magnetic torque generator to control the satellite's attitude angular velocity to the predetermined angular velocity, and autonomously switch to the magnetic sun-alignment sub-mode; Step 2: Run the magnetic solar orientation sub-mode to continue providing the magnetic moment required for satellite spin orientation, and use the solar sensor to measure the direction of the solar vector, and use the magnetic torque meter to precess the satellite spin axis towards the solar direction; Step 3: After receiving the ground command, the satellite despins through magnetic damping and then autonomously switches to the magnetic Earth orientation sub-mode. It uses the star sensor for attitude determination without gyroscopes, determines the satellite attitude using the star sensor, and achieves three-axis stable Earth orientation through magnetic torque control. In the magnetic spinner mode, satellite attitude angular velocity estimation includes: One-step prediction: New interest calculation: Filter correction: in, It is the control torque value calculated based on the control quantity of the previous cycle; and It is the unit vector of the magnetic field direction for the current and previous periods. These are the filter correction coefficients. , These are the estimated angular velocities for the current and previous cycles. The sampling period; The magnetic capture and orientation phase is divided into a magnetic damping sub-mode and a magnetic orientation sub-mode. In the magnetic damping sub-mode, star-sensor measurement and magnetic moment control are used to achieve satellite rate damping and despinning. In the magnetic orientation sub-mode, the satellite uses a star sensor to determine its attitude and uses a magnetic torque controller to achieve three-axis stable orientation to Earth. In the magnetic-to-ground orientation sub-mode, the satellite uses a star sensor to determine its attitude. and angular velocity The satellite's three-axis stable orientation to Earth is achieved through magnetic torque control. The calculation formula is Magnetic moment in, and All are adjustable control gains. , , and These are the reference attitude angle and angular velocity, respectively.

2. The satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control according to claim 1, characterized in that, In the magnetic spinon mode, the predicted angular velocity is utilized. Magnetic moment control enables rate damping of the satellite, allowing it to spin at a specified angular velocity, and magnetic torque control. The calculation formula is in, This represents the difference multiplication operation. For adjustable control gain, The nominal angular velocity of spin. It is the unit vector of the magnetic field direction for this period.

3. The satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control according to claim 1, characterized in that, In the magnetic heliocentric sub-mode, the first step is to base the results on digital solar measurements, the desired angular velocity of heliocentric rotation, and... Obtain magnetic moment variable ; Then use the assignment formula Calculate magnetic moment Finally, the formula for calculating the control magnetic moment is as follows: ; in, For adjustable control gain, the magnetic moment in the magnetic sun-oriented sub-mode The initial value is 0.

4. The satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control according to claim 1, characterized in that, In the magnetic damping sub-mode, the satellite's three-axis angular velocity signals are provided by star-sensor measurements, and the target angular velocity is set to zero to achieve satellite despinning.

5. A satellite attitude safety acquisition control system based on magnetic measurement and magnetic control, based on the satellite attitude safety acquisition control method based on magnetic measurement and magnetic control as described in claim 1, characterized in that, include: The magnetic spin module operates in magnetic spin sub-mode, using a magnetometer to filter and estimate the satellite's attitude angular velocity. It then uses a magnetic torque converter to control the satellite's attitude angular velocity to a predetermined value before autonomously switching to magnetic sun-alignment sub-mode. The magnetic sun orientation module runs the magnetic sun orientation sub-mode, continues to provide the magnetic moment required for satellite spin orientation, and uses a sun sensor to measure the direction of the sun vector, and uses a magnetic torque device to precess the satellite spin axis toward the sun. After receiving ground commands, the magnetic ground acquisition module autonomously switches to the magnetic ground orientation sub-mode after de-spinning the satellite through magnetic damping. It then uses a star sensor for attitude determination without a gyroscope, determines the satellite's attitude using the star sensor, and achieves three-axis stable Earth orientation through magnetic torque control.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 4.

7. A computer software product, characterized in that... include: Processors and storage devices; Storage device for storing one or more programs. When the one or more programs are executed by one or more processors, the one or more processors implement the satellite attitude safety acquisition and control method based on magnetic measurement and magnetic control as described in any one of claims 1 to 4.

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