Control method and device of large-flexibility double-shaft solar panel

Abstract

The invention provides a control method and device of a large-flexibility double-shaft solar panel. The method comprises the following steps: respectively calculating target rotation angles of an alpha axis and a beta axis aiming at the sun based on projections of a sun azimuth in a body coordinate system and an orbital coordinate system; the current rotation angles of the alpha axis and the beta axis are subtracted from the target rotation angles of the alpha axis and the beta axis respectively, and current tracking errors of the alpha axis and the beta axis are obtained; the current tracking errors of the alpha axis and the beta axis are compared with a set threshold value, and if the current tracking errors of the alpha axis or the beta axis exceed the set threshold value, the capture control strategy of the alpha axis or the beta axis is used for conducting autonomous capture; if the current tracking errors of the alpha axis and the beta axis both exceed the set threshold value, the capture sequence of the alpha axis and the beta axis in the double-axis sailboard is determined according to the operation state of the alpha axis, and the capture control strategies of the alpha axis and the beta axis are sequentially used for conducting autonomous capture according to the capture sequence. According to the scheme, smooth and stable control over the large-flexibility solar double-shaft sailboard can be achieved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of spacecraft dual-axis sailboard control, and in particular to a control method and device for a highly flexible dual-axis solar sailboard. Background Art

[0002] Satellites with solar panels need to aim the solar panels at the sun to obtain energy. For satellites equipped with a dual-axis solar panel drive mechanism (including the α-axis and the β-axis, where the α-axis is connected to the satellite body), the satellite's attitude remains unchanged on three axes relative to the ground, and the dual-axis solar panel drive mechanism can be used to aim the solar panels at the sun.

[0003] In the related art, the traditional dual-axis solar panel control is to set the speed gears of multiple panel driving mechanisms, and eliminate the panel tracking error by adjusting the speed gears according to the panel tracking error. In addition, when the speed gears are switched, the driving mechanism adopts a direct switching method, and the speed gear size and direction are determined only according to the size of the tracking error. There is no constraint on the rotational angular acceleration, and there is no constraint on the speed direction switching.

[0004] However, for large flexible solar panels, their characteristics are low fundamental frequency, large inertia, easy to excite, and there is a strong coupling between the panel control and the attitude control of the satellite. Rapid acceleration (or deceleration) or sudden switching of the speed direction will have a large impact on the large flexible panel, causing the large flexible panel to vibrate greatly, which will not only affect the stability of the satellite attitude, but also bring very large disturbances to the control of the large flexible panel, and in severe cases will cause the control of the large flexible panel to diverge.

[0005] Therefore, there is an urgent need to provide a control method and device for a large flexible dual-axis solar sail panel. Summary of the invention

[0006] In order to solve the problem that the traditional dual-axis solar sail panel control method is difficult to achieve smooth and stable control of a large flexible solar sail panel, an embodiment of the present invention provides a control method and device for a large flexible dual-axis solar sail panel.

[0007] In a first aspect, an embodiment of the present invention provides a control method for a large flexible dual-axis solar sail panel, wherein a large flexible dual-axis sail panel driving mechanism includes an α-axis and a β-axis, wherein the α-axis is connected to a satellite body, and the β-axis is connected to a driving mechanism body of the α-axis;

[0008] Methods include:

[0009] Get the current rotation angles of the α-axis and β-axis in the dual-axis sailboard;

[0010] Based on the projection of the sun's position in the satellite's body coordinate system and the orbital coordinate system, respectively calculating the target rotation angles of the α-axis and the β-axis aligned with the sun;

[0011] Subtracting the current rotation angles of the α-axis and the β-axis from the target rotation angles of the α-axis and the β-axis aligned with the sun, respectively, to obtain current tracking errors of the α-axis and the β-axis;

[0012] Comparing the current tracking errors of the α-axis and the β-axis with set thresholds respectively, and if the current tracking errors of the α-axis or the β-axis exceed the set thresholds, autonomous capture is performed using the capture control strategy of the α-axis or the β-axis respectively;

[0013] If the current tracking errors of the α-axis and the β-axis both exceed the set threshold, the capture order of the α-axis and the β-axis in the dual-axis sailboard is determined according to the operating state of the α-axis, and the capture control strategies of the α-axis and the β-axis are used in turn according to the capture order to perform autonomous capture to achieve dual-axis decoupling control.

[0014] In a second aspect, an embodiment of the present invention further provides a control device for a large flexible dual-axis solar sail panel, wherein the large flexible dual-axis solar sail panel comprises an α-axis and a β-axis, wherein the α-axis is connected to a satellite body, and the β-axis is connected to a driving mechanism body of the α-axis;

[0015] The device includes:

[0016] A data acquisition unit, used to obtain the current rotation angles of the α-axis and the β-axis of the dual-axis sailboard;

[0017] A target rotation angle calculation unit, used to calculate the target rotation angles of the α-axis and the β-axis aligned with the sun, based on the projection of the sun's position in the satellite body coordinate system and the orbit coordinate system;

[0018] A tracking error calculation unit, used for respectively subtracting the current rotation angles of the α-axis and the β-axis from the target rotation angles of the α-axis and the β-axis aligned with the sun to obtain the tracking errors of the α-axis and the β-axis;

[0019] An autonomous capture control unit, used to compare the current tracking errors of the α-axis and the β-axis with set thresholds respectively, and if the current tracking errors of the α-axis or the β-axis exceed the set threshold, autonomous capture is performed using the capture control strategy of the α-axis or the β-axis respectively;

[0020] If the tracking errors of the α-axis and the β-axis both exceed the set threshold, the capture order of the α-axis and the β-axis in the dual-axis sailboard is determined according to the operating state of the α-axis, and the capture control strategies of the α-axis and the β-axis are used in turn according to the capture order to perform autonomous capture to achieve dual-axis decoupling control.

[0021] In a third aspect, an embodiment of the present invention further provides a computing device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method described in any embodiment of this specification is implemented.

[0022] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, enables the computer to execute the method described in any embodiment of this specification.

[0023] On the other hand, an embodiment of the present application further provides a computer program product, which includes a computer program. A processor of a computer device reads the computer program from a computer-readable storage medium, and the processor executes the computer program, so that the computer device executes any of the methods described in the above embodiments.

[0024] The embodiment of the present invention provides a control method and device for a large-flexibility dual-axis solar sail panel. The current tracking errors of the α-axis and the β-axis are obtained by subtracting the current rotation angles of the α-axis and the β-axis from the target rotation angle aligned with the sun, and the current tracking errors of the α-axis and the β-axis are compared with set thresholds respectively. If the current tracking errors of the α-axis and the β-axis both exceed the set thresholds, the capture order of the α-axis and the β-axis is first determined according to the current operating state of the α-axis, and then the α-axis or the β-axis is started in sequence for autonomous capture according to the determined capture order and further combined with the capture control strategy of the α-axis and the β-axis; in this way, decoupling control of the two axes in the solar dual-axis sail panel is realized, smooth speed regulation control of the α-axis under multiple constraints and long-period fixed angle holding control of the β-axis are realized, the flexible vibration of the solar sail panel is reduced, and smooth and stable control of the large-flexibility dual-axis solar sail panel is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 is a flow chart of a control method of a large flexible dual-axis solar sail panel provided by an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of a highly flexible dual-axis solar sail panel structure provided by an embodiment of the present invention;

[0028] Figure 3 is a hardware architecture diagram of a computing device provided by an embodiment of the present invention;

[0029] Figure 4 It is a structural diagram of a control device for a large flexible dual-axis solar sail panel provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] Please refer to Figure 1 , an embodiment of the present invention provides a control method for a large flexible dual-axis solar sailboard, wherein the large flexible dual-axis sailboard driving mechanism comprises an α-axis and a β-axis, wherein the α-axis is connected to a satellite body, and the β-axis is connected to a driving mechanism body of the α-axis;

[0032] The method includes:

[0033] Step 100, obtaining the current rotation angles of the α-axis and the β-axis in the large flexible biaxial sailboard;

[0034] Step 102, based on the projection of the sun's position in the satellite's body coordinate system and the orbital coordinate system, respectively calculate the target rotation angles of the α-axis and the β-axis aligned with the sun;

[0035] Step 104, respectively subtracting the current rotation angles of the α-axis and the β-axis from the target rotation angles of the α-axis and the β-axis aligned with the sun to obtain current tracking errors of the α-axis and the β-axis;

[0036] Step 106, comparing the current tracking errors of the α-axis and the β-axis with set thresholds respectively, and if the current tracking errors of the α-axis or the β-axis exceed the set threshold, autonomous capture is performed using the capture control strategy of the α-axis or the capture control strategy of the β-axis respectively;

[0037] Step 108, if the current tracking errors of the α-axis and the β-axis both exceed the set threshold, the capture order of the α-axis and the β-axis in the dual-axis sailboard is determined according to the operating state of the α-axis, and the capture control strategies of the α-axis and the β-axis are used in turn according to the capture order to perform autonomous capture to achieve dual-axis decoupling control.

[0038] In an embodiment of the present invention, the current tracking errors of the α-axis and the β-axis are obtained by subtracting the current rotation angles of the α-axis and the β-axis from the target rotation angle aligned with the sun, and the current tracking errors of the α-axis and the β-axis are compared with set thresholds respectively. If the current tracking errors of the α-axis and the β-axis both exceed the set thresholds, the capture order of the α-axis and the β-axis is first determined according to the current operating state of the α-axis, and then the α-axis or the β-axis is started in sequence for autonomous capture according to the determined capture order and further combined with the capture control strategy of the α-axis and the β-axis; in this way, decoupling control of the two axes in the solar dual-axis sailboard is realized, smooth speed regulation control of the α-axis under multiple constraints and long-period fixed angle holding control of the β-axis are realized, the flexible vibration of the large-flexibility solar sailboard is reduced, and smooth and stable control of the dual-axis solar sailboard is realized.

[0039] For step 100:

[0040] like Figure 2 As shown, in the embodiment of the present invention, the large flexible dual-axis sailboard includes two axes, the α-axis and the β-axis. The α-axis is an axis connected to the satellite cabin body and rotates relative to the cabin body. The β-axis is an axis connected to the α-axis drive mechanism body, and its load is the solar wing, which rotates relative to the α-axis drive mechanism body. During the satellite's flight over the earth (the satellite system and the orbital system are approximately coincident), the sun's position relative to the star body is a real change. The α-axis and the β-axis need to be rotated to the appropriate position to align the sailboard normal with the sun. The α-axis is used to track the projection of the sun's position in the orbital plane in real time, and the β-axis is used to compensate for the change of the sun's position outside the orbital plane.

[0041] For steps 102 and 104:

[0042] In some embodiments, the target rotation angles of the α-axis and the β-axis toward the sun are calculated by the following formulas:

[0043] α Fsm =arctan2(-S bx , -S bz )

[0044] β n =arcsin(-S oy )

[0045] In the formula, α Fsm is the target rotation angle of the α axis toward the sun, β n is the target rotation angle of the β axis toward the sun, [S ox , S oy , S oz ] is the projection of the sun’s position in the orbital coordinate system, [S bx , S by , S bz ] is the projection of the sun’s position in the body coordinate system.

[0046] In an embodiment of the present invention, the target rotation angle of the α-axis and the target (theoretical) rotation angle of the β-axis aligned with the sun are first calculated based on the solar azimuth angle, and then the current tracking error of the two axes is obtained by subtracting the obtained current rotation angles of the α-axis and β-axis from the target rotation angles of the α-axis and β-axis aligned with the sun. When the current tracking error exceeds a set threshold, capture is required.

[0047] For steps 106 to 108:

[0048] In the embodiment of the present invention, the capture process is divided into the following two cases: if the current tracking error of one of the two axes exceeds the set threshold, the axis (for example, the α-axis or the β-axis) that exceeds the set threshold is captured; if the current tracking errors of both axes exceed the set threshold, both axes (the α-axis and the β-axis) need to be captured, but for a large-flexibility dual-axis controlled sailboard, when the two axes need to be captured at the same time, it is necessary to first determine the priority of capturing the two axes to achieve decoupling of the two axes, thereby effectively avoiding the vibration of the sailboard caused by the simultaneous speed regulation of the two axes, and ensuring the stability of the control of the large-flexibility dual-axis sailboard.

[0049] In some embodiments, the operating state of the α-axis includes stalling, capturing operation, or steady-state tracking (stable tracking at an orbital angular velocity);

[0050] In step 104, the capture order of the α-axis and the β-axis in the dual-axis sailboard is determined according to the operating state of the α-axis, including:

[0051] If the α-axis is in a stopped state or a steady tracking state, the capture order of the two axes in the large flexible dual-axis sailboard is determined as first capturing the β-axis and then capturing the α-axis;

[0052] If the α-axis is in the capturing operation state, the capturing order of the two axes in the large-flexibility biaxial sailboard is determined as capturing the α-axis first and then the β-axis.

[0053] In the embodiment of the present invention, the characteristics of the α-axis and the β-axis in the highly flexible dual-axis sailboard are taken into consideration. The load characteristics of the β-axis (such as inertia, etc.) remain unchanged, while when the β-axis rotates, the load characteristics of the α-axis are actually changed, and its inertia may change greatly. Therefore, in the control process of the α-axis, especially in the speed regulation process of the α-axis, the rotation of the β-axis should be avoided as much as possible. Based on this, in the embodiment of the present invention, the capture order of the two sailboards is determined by the operating state of the α-axis. When the operating state of the α-axis is in a state of stop or steady-state tracking, the β-axis is captured first (when the ground intervenes, the capture is performed according to the priority order specified by the ground). When the operating state of the α-axis is in capture operation, the α-axis capture is implemented first, and the two axes complete the capture in time-sharing order.

[0054] In some embodiments, the capture control strategy of the α-axis is as follows:

[0055] Constructing a trajectory planning function for α-axis capture; wherein the trajectory planning function is a quintic polynomial trajectory planning function;

[0056] Solving various parameters of the trajectory planning function using preset constraints to obtain an expression of the trajectory planning function; wherein the preset constraints include position constraints, speed constraints, and acceleration constraints;

[0057] According to the current operating state of the α-axis and the trajectory planning function expression, the capture strategy of the α-axis is determined; wherein the capture strategy includes acceleration and catching up, deceleration and waiting, or stop and wait.

[0058] When driving the large flexible sailboard to rotate, the α-axis drive mechanism has the following constraints: the capture process cannot change the direction of the speed, and additional start-stop operations should be avoided as much as possible; during the sailboard speed adjustment process, the maximum speed and maximum angular acceleration must be less than a certain threshold, and the minimum speed must be greater than a certain threshold; the angle and speed must be captured synchronously, and when the angle reaches the target value, the speed also reaches the target speed to avoid frequent speed adjustment. Under this constraint, in an embodiment of the present invention, the autonomous capture of the α-axis is achieved by using a polynomial trajectory planning method, wherein the speed regulation of the α-axis is planned under the condition of limiting the angular acceleration, and the speed change planning of the α-axis is realized. Specifically, by first constructing the trajectory planning function (quintic polynomial trajectory planning function) of the α-axis capture:

[0059] f(t)=a·t 5 +b·t 4 +c·t 3 +d·t 2 +e·t+f

[0060] Where f(t) is the angular position at time t (planned value), a, b, c, d, e, and f are unknown parameters, and the derivative f'(t) of f(t) is the planned speed at time t, that is, the target speed of the α-axis at time t. The planning function is second-order differentiable, thus ensuring the continuity and smoothness of the planned speed.

[0061] The above trajectory planning function needs to satisfy three preset constraints: position constraint, velocity constraint and acceleration constraint:

[0062] Position constraints:

[0063]

[0064] That is, the initial position is S1, the target position is S2, and at t max At this moment, the α axis rotates to the target angle α Fsm ;

[0065] Speed ​​Constraints:

[0066]

[0067] That is, the initial speed is v1, the final speed is v2, and the maximum value of the first-order derivative of the function (speed) is less than or equal to the maximum speed v of the constraint max , the minimum velocity must be greater than or equal to v min ;

[0068] Acceleration constraints:

[0069]

[0070] That is, the initial acceleration is 0, the final acceleration is zero, and the maximum value of the second-order derivative of the function (acceleration) is less than or equal to the constrained maximum acceleration a max .

[0071] Through the above constraints, the various unknown parameters of the trajectory planning function can be obtained, thereby obtaining the trajectory planning function expression. Based on this expression, the trajectory planning curve of the α-axis with respect to time and position can be further obtained, and further combined with the operating state of the α-axis to determine the capture strategy of the α-axis.

[0072] In some implementations, determining the capture strategy of the α-axis according to the current operating state of the α-axis and the trajectory planning function expression includes:

[0073] If the current α-axis is in a stopped state, the time for the sun's azimuth to reach the current position of the α-axis and the time t1 and t2 required for the α-axis to start one-way capture of the sun are calculated respectively according to the trajectory planning function expression, and the method with the shorter required time is determined as the capture strategy of the α-axis;

[0074] If the current α-axis is in a steady-state tracking state or a rotation capture state, the times t3 and t4 required for acceleration pursuit and deceleration waiting are calculated respectively according to the trajectory planning function, and the method with the shorter required time is determined as the capture strategy of the α-axis.

[0075] In the embodiment of the present invention, there are three capture strategies for the α-axis, including acceleration pursuit (maximum speed limit), deceleration waiting (minimum speed limit), and stop waiting (at this time, the speed at which the tracking error decreases is equal to the satellite orbit angular velocity ω o The same), according to the polynomial trajectory planning method, the values ​​of t1~t4 can be accurately solved, and a shorter time method is adopted as the capture strategy of the α-axis. The capture process uses the trajectory planning curve of the α-axis about time and position obtained by the above polynomial trajectory planning function to capture, thereby realizing the synchronous and accurate capture of the angle and speed.

[0076] Thus, in the embodiment of the present invention, after the above-mentioned capture optimization and speed change planning, the capture of the α-axis not only meets various constraints, but also achieves the purpose of smooth speed change, and realizes the synchronous and precise capture of the angle and rotation speed, reduces the impact of the speed regulation process, avoids the excitation of the flexible vibration of the sailboard, and realizes the smooth control of the large-flexibility dual-axis sailboard, thereby avoiding large disturbances to the attitude of the spacecraft.

[0077] The control of the β-axis of the sailboard has the following constraints: when the α-axis rotates, the β-axis speed must be less than a certain threshold; the adjustment of the β-axis angular position should be minimized to reduce the impact on the rotation of the α-axis; the rotation of the β-axis does not require the sailboard normal to be completely aligned with the sun, and a certain deviation is allowed, and the deviation angle meets a certain threshold; when the β-axis angle increases or decreases, a certain hysteresis interval needs to be set to avoid switching back and forth. Based on the above constraints, the following capture control strategy for the β-axis is formulated.

[0078] In some embodiments, the capture control strategy of the β axis is as follows:

[0079] The angle variation range between the sun's azimuth and the orbital plane is divided into equal intervals to obtain a number of gear holding angles;

[0080] Subtract the target rotation angle of the β-axis toward the sun from each of the gear holding angles in turn, and if the obtained deviation angle is not greater than the gear switching deviation angle, determine the current corresponding gear holding angle as the initial gear holding angle of the β-axis; wherein the gear switching deviation angle is set according to energy constraints and hysteresis loop width;

[0081] Determining whether the current tracking error of the β-axis is greater than the gear switching deviation angle, and if not, controlling the β-axis to remain in the current gear;

[0082] If so, the required gear holding angle is re-determined, and the β-axis is controlled to rotate to the target gear according to the operating state of the α-axis.

[0083] In the embodiment of the present invention, in order to reduce the adjustment of the β-axis angular position as much as possible, the fixed position of the β-axis fixed angle holding (i.e., the gear holding angle) is first designed: by dividing n equally spaced points within the angle variation range between the solar azimuth and the orbital plane, a number of gear holding angles are obtained, and the gear interval angle is δ, then the β-axis can stop at 0°, ±δ, ±2δ, ..., ±kδ (k=1~n) positions, -kδ~+kδ needs to cover the angle variation range between the solar azimuth and the orbital plane, and n is generally less than 10; then, according to the energy constraint and the hysteresis loop width requirement of the angular position switching, the gear switching deviation angle (defined as γ) is designed, and the gear switching deviation angle and the gear interval angle satisfy the following relationship:

[0084] 2γ-δ≥H0

[0085] Wherein, γ is the gear switching deviation angle, δ is the gear interval angle, and H0 is the required minimum hysteresis loop width;

[0086] When the β-axis switches between two adjacent gear positions, there needs to be a sufficient hysteresis width to avoid frequent rotation of the β-axis caused by the back-and-forth switching of gears.

[0087] When the β-axis is switched from the non-autonomous fixed-angle holding mode to the autonomous fixed-angle holding mode for the first time, it is necessary to first select the initial gear holding angle according to the target rotation angle βn of the β-axis aligned with the sun: βn is sequentially subtracted from the gear holding angles 0°, ±δ, ±2δ, ±3δ, …, ±kδ to obtain several deviation angles θ. When a certain deviation angle θ satisfies |θ|≤γ, the current gear holding angle is determined as the initial gear holding angle βn0 that the β-axis needs to maintain at a fixed angle. In the autonomous fixed-angle holding mode, during the change of the solar azimuth, the deviation between the target rotation angle of the β-axis aligned with the sun and the current rotation angle position of the β-axis (i.e., the current tracking error of the β-axis) is calculated in real time, and the tracking error is compared with the gear switching deviation angle γ in real time. When the current tracking error is less than the gear switching deviation angle γ, the β-axis remains unchanged at the current gear. When the current tracking error exceeds the gear switching deviation angle γ, it is necessary to further control the β-axis to rotate to the target gear in combination with the operating state of the α-axis. Specifically, when the α-axis is in a stopped state, the β-axis uses a high speed to reach the next gear. When the α-axis is in an operating state, it uses a low speed to reach the next gear. This not only meets the energy needs of the entire satellite, but also reduces the impact on the rotation of the α-axis.

[0088] By adopting the above β-axis autonomous fixed-angle holding strategy, the deviation of the β-axis sailboard normal to the sun is always controlled within the gear switching deviation angle γ. In addition, the hysteresis width of the β-axis switching between two adjacent gears is 2γ-δ. Appropriate parameters are designed to avoid switching back and forth. The time interval for adjusting the gear of the β-axis is long, ranging from one week to several weeks (determined by the speed of the change in the sun's position). The influence of occasional slow switching on the sailboard α-axis control can be almost ignored, realizing dual-axis decoupling control and avoiding disturbances to the spacecraft attitude.

[0089] In summary, in the embodiment of the present invention, firstly, according to the decoupling control strategy of the large flexible dual-axis sailboard, the priority of the two-axis capture is determined, and the two-axis time-sharing capture method is realized. When the α-axis of the large flexible sailboard captures the sun, firstly, according to the current state and constraints of the α-axis, the target position, etc., the capture optimization of the α-axis is performed to determine the capture method to be adopted; secondly, an α-axis autonomous capture control method based on quintic polynomial trajectory planning is designed to realize smooth speed change, angle and speed synchronous and precise capture of the α-axis. When the β-axis captures the sun, a β-axis long-period autonomous fixed-angle holding control method with hysteresis is designed to realize that the β-axis stays at the set position for a long time, and occasionally switches slowly, so as to avoid the frequent position adjustment of the β-axis causing disturbance to the α-axis control.

[0090] According to the method in this embodiment, the rotation of the large flexible dual-axis sailboard is controlled, and the required parameters can be obtained, which is convenient for the spacecraft to be realized in orbit. The normal of the sailboard approximately points to the sun, which meets the energy needs of the entire satellite and realizes smooth control of the large flexible dual-axis sailboard, avoiding the vibration of the large flexible sailboard affecting the stability of the satellite attitude.

[0091] The dual-axis sailboard control method described in the present invention was used for the first time on a certain type of spacecraft in my country. On-orbit tests showed that the α-axis speed regulation process was continuous and smooth, achieving smooth control of the dual-axis sailboard, and the tracking error of the sailboard normal to the sun met the energy requirements of the entire satellite.

[0092] like Figure 3 , Figure 4 As shown, an embodiment of the present invention provides a control device for a large flexible dual-axis solar sail panel. The device embodiment can be implemented by software, or by hardware or a combination of software and hardware. From the hardware level, Figure 3 As shown, it is a hardware architecture diagram of a computing device where a control device of a large flexible dual-axis solar sail panel provided by an embodiment of the present invention is located. Figure 3 In addition to the processor, memory, network interface, and non-volatile memory shown in the figure, the computing device in which the device is located in the embodiment may also generally include other hardware, such as a forwarding chip responsible for processing messages, etc. Taking software implementation as an example, Figure 4 As shown, as a device in a logical sense, the CPU of the computing device in which it is located reads the corresponding computer program in the non-volatile memory into the memory and runs it. This embodiment provides a control device for a large flexible dual-axis solar sail panel, the large flexible dual-axis sail panel includes an α-axis and a β-axis, the α-axis is connected to the satellite body, and the β-axis is connected to the driving mechanism body of the α-axis;

[0093] The device includes:

[0094] The data acquisition unit 401 is used to obtain the current rotation angles of the α-axis and the β-axis of the dual-axis windsurfing board;

[0095] The target rotation angle calculation unit 402 calculates the target rotation angles of the α-axis and the β-axis aligning with the sun respectively by using the projection of the sun's position in the satellite body coordinate system and the orbit coordinate system;

[0096] A tracking error calculation unit 403, used to respectively subtract the current rotation angles of the α-axis and the β-axis from the target rotation angles of the α-axis and the β-axis aligned with the sun to obtain the tracking errors of the α-axis and the β-axis;

[0097] An autonomous capture control unit 404 is used to compare the current tracking errors of the α-axis and the β-axis with a set threshold value respectively, and if the current tracking error of the α-axis or the β-axis exceeds the set threshold value, autonomous capture is performed using the capture control strategy of the α-axis or the β-axis respectively;

[0098] If the tracking errors of the α-axis and the β-axis both exceed the set threshold, the capture order of the α-axis and the β-axis in the dual-axis sailboard is determined according to the operating state of the α-axis, and the capture control strategies of the α-axis and the β-axis are used in turn according to the capture order to perform autonomous capture to achieve dual-axis decoupling control.

[0099] In an embodiment of the present invention, the data acquisition unit 401 can be used to execute step 100 in the above method embodiment, the target angle calculation unit 402 can be used to execute step 102 in the above method embodiment, the tracking error calculation unit 403 can be used to execute step 104 in the above method embodiment, and the autonomous capture control unit 404 can be used to execute steps 106 and 108 in the above method embodiment.

[0100] In one embodiment of the present invention, in the target rotation angle calculation unit 402, the target rotation angles of the α-axis and the β-axis toward the sun are calculated by the following formulas:

[0101] α Fsm =arctan2(-S bx , -S bz )

[0102] β n =arcsin(-S oy )

[0103] In the formula, α Fsm is the target rotation angle of the α axis toward the sun, β n is the target rotation angle of the β axis toward the sun, [S ox , S oy , S oz ] is the projection of the sun’s position in the orbital coordinate system, [S bx , S by , S bz ] is the projection of the sun’s position in the body coordinate system.

[0104] In one embodiment of the present invention, in the tracking error calculation unit 403, the operation state of the α-axis includes stalling, capturing operation or steady-state tracking;

[0105] The tracking error calculation unit 403 determines the capture order of the α-axis and the β-axis in the dual-axis windsurfing board according to the operating state of the α-axis, and is used to perform the following operations:

[0106] If the α-axis is in a stopped state or a steady tracking state, the capture order of the two axes in the large flexible dual-axis sailboard is determined as first capturing the β-axis and then capturing the α-axis;

[0107] If the α-axis is in the capturing operation state, the capturing order of the two axes in the large-flexibility biaxial sailboard is determined as capturing the α-axis first and then the β-axis.

[0108] In one embodiment of the present invention, in the autonomous capture control unit 404, the capture control strategy of the α-axis is as follows:

[0109] Constructing a trajectory planning function for α-axis capture; wherein the trajectory planning function is a quintic polynomial trajectory planning function;

[0110] Solving various parameters of the trajectory planning function using preset constraints to obtain an expression of the trajectory planning function; wherein the preset constraints include position constraints, speed constraints, and acceleration constraints;

[0111] According to the current operating state of the α-axis and the trajectory planning function expression, the capture strategy of the α-axis is determined; wherein the capture strategy includes acceleration and catching up, deceleration and waiting, or stop and wait.

[0112] In one embodiment of the present invention, in the autonomous capture control unit 404, the capture strategy of the α-axis is determined according to the current operating state of the α-axis and the trajectory planning function expression, including:

[0113] If the current α-axis is in a stopped state, the time for the sun's azimuth to reach the current position of the α-axis and the time required for the α-axis to start one-way capture are calculated according to the trajectory planning function expression, and the method with the shorter required time is determined as the capture strategy for the α-axis;

[0114] If the current α-axis is in a steady-state tracking state or a rotation capture state, the time required for acceleration and deceleration is calculated according to the trajectory planning function, and the method with the shorter time is determined as the capture strategy of the α-axis.

[0115] In one embodiment of the present invention, in the autonomous capture control unit 404, the capture control strategy of the β axis is as follows:

[0116] The angle variation range between the sun's azimuth and the orbital plane is divided into equal intervals to obtain a number of gear holding angles;

[0117] Subtract the target rotation angle of the β-axis toward the sun from each of the gear holding angles in turn, and if the obtained deviation angle is not greater than the gear switching deviation angle, determine the current corresponding gear holding angle as the initial gear holding angle of the β-axis; wherein the gear switching deviation angle is set according to energy constraints and hysteresis loop width;

[0118] Determining whether the current tracking error of the β-axis is greater than the gear switching deviation angle, and if not, controlling the β-axis to remain in the current gear;

[0119] If so, the required gear holding angle is re-determined, and the β-axis is controlled to rotate to the target gear according to the operating state of the α-axis.

[0120] In one embodiment of the present invention, in the autonomous capture control unit 404, the gear switching deviation angle and the gear interval angle satisfy the following relationship:

[0121] 2γ-δ≥H0

[0122] Wherein, γ is the gear switching deviation angle, δ is the gear interval angle, and H0 is the required minimum hysteresis loop width.

[0123] It is understood that the structure illustrated in the embodiment of the present invention does not constitute a specific limitation on the control device of a large flexible dual-axis solar sail panel. In other embodiments of the present invention, a control device of a large flexible dual-axis solar sail panel may include more or fewer components than shown in the figure, or combine some components, or split some components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0124] The information interaction, execution process and other contents between the modules in the above-mentioned device are based on the same concept as the embodiment of the method of the present invention. For the specific contents, please refer to the description in the embodiment of the method of the present invention, and no further description is given here.

[0125] An embodiment of the present invention further provides a computing device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, a control method for a large flexible dual-axis solar sail panel in any embodiment of the present invention is implemented.

[0126] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the processor executes a control method for a large flexible dual-axis solar sail panel in any embodiment of the present invention.

[0127] Specifically, a system or device equipped with a storage medium can be provided, on which software program code that implements the functions of any of the above-mentioned embodiments is stored, and a computer (or CPU or MPU) of the system or device can be enabled to read and execute the program code stored in the storage medium.

[0128] In this case, the program code itself read from the storage medium can realize the function of any one of the above-mentioned embodiments, and thus the program code and the storage medium storing the program code constitute a part of the present invention.

[0129] The storage medium embodiments for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program code can be downloaded from a server computer by a communication network.

[0130] In addition, it should be clear that the functions of any of the above embodiments can be implemented not only by executing the program code read by the computer, but also by enabling an operating system operating on the computer to complete part or all of the actual operations based on instructions from the program code.

[0131] In addition, it can be understood that the program code read from the storage medium is written to a memory provided in an expansion board inserted into the computer or to a memory provided in an expansion module connected to the computer, and then based on the instructions of the program code, a CPU installed on the expansion board or expansion module is enabled to perform part or all of the actual operations, thereby realizing the functions of any of the above-mentioned embodiments.

[0132] An embodiment of the present application also provides a computer-readable storage medium, on which is stored at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by a processor to implement a control method for a large flexible dual-axis solar panel provided in the above-mentioned method embodiments.

[0133] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0134] A person of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, etc., various media that can store program codes.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for a large flexible dual-axis solar sail panel, characterized in that: The large-flexibility dual-axis sailboard driving mechanism comprises an α-axis and a β-axis, wherein the α-axis is connected to the satellite body, and the β-axis is connected to the driving mechanism body of the α-axis; Methods include: Get the current rotation angles of the α-axis and β-axis in the large flexible biaxial sailboard; Based on the projection of the sun's position in the satellite's body coordinate system and the orbital coordinate system, respectively calculating the target rotation angles of the α-axis and the β-axis aligned with the sun; Subtracting the current rotation angles of the α-axis and the β-axis from the target rotation angles of the α-axis and the β-axis aligned with the sun, respectively, to obtain current tracking errors of the α-axis and the β-axis; Comparing the current tracking errors of the α-axis and the β-axis with set thresholds respectively, and if the current tracking errors of the α-axis or the β-axis exceed the set thresholds, autonomous capture is performed using the capture control strategy of the α-axis or the capture control strategy of the β-axis respectively; If the current tracking errors of the α-axis and the β-axis both exceed the set threshold, the capture order of the α-axis and the β-axis in the dual-axis sailboard is determined according to the operating state of the α-axis, and the capture control strategies of the α-axis and the β-axis are used in turn according to the capture order to perform autonomous capture to achieve dual-axis decoupling control.

2. The method according to claim 1, characterized in that The target rotation angles of the α-axis and the β-axis toward the sun are calculated by the following formulas: α Fsm =arctan2(-S bx ,-S bz ) β n =arcsin(-S oy ) In the formula, α Fsm is the target rotation angle of the α axis toward the sun, β n is the target rotation angle of the β axis toward the sun, [S ox , S oy , S oz ] is the projection of the sun’s position in the orbital coordinate system, [S bx , S by , S bz ] is the projection of the sun’s position in the body coordinate system.

3. The method according to claim 1, characterized in that The operating state of the α-axis includes stalling, capturing operation or steady-state tracking; The step of determining the capture order of the α-axis and the β-axis in the dual-axis windsurfing board according to the operating state of the α-axis comprises: If the α-axis is in a stopped state or a steady tracking state, the capture order of the two axes in the large flexible dual-axis sailboard is determined as first capturing the β-axis and then capturing the α-axis; If the α-axis is in the capturing operation state, the capturing order of the two axes in the large-flexibility biaxial sailboard is determined as capturing the α-axis first and then the β-axis.

4. The method according to claim 1 or 3, characterized in that: The capture control strategy of the α-axis is as follows: Constructing a trajectory planning function for α-axis capture; wherein the trajectory planning function is a quintic polynomial trajectory planning function; Solving various parameters of the trajectory planning function using preset constraints to obtain an expression of the trajectory planning function; wherein the preset constraints include position constraints, speed constraints, and acceleration constraints; According to the current operating state of the α-axis and the trajectory planning function expression, the capture strategy of the α-axis is determined; wherein the capture strategy includes acceleration and catching up, deceleration and waiting, or stop and wait.

5. The method according to claim 4, characterized in that The step of determining the capture strategy of the α-axis according to the current operating state of the α-axis and the trajectory planning function expression includes: If the current α-axis is in a stopped state, the time for the sun's azimuth to reach the current position of the α-axis and the time required for the α-axis to start one-way capture of the sun are calculated according to the trajectory planning function expression, and the method with the shorter required time is determined as the capture strategy of the α-axis; If the current α-axis is in a steady-state tracking state or a rotation capture state, the time required for acceleration and deceleration is calculated according to the trajectory planning function, and the method with the shorter time is determined as the capture strategy of the α-axis.

6. The method according to claim 1, characterized in that The capture control strategy of the β axis is as follows: The angle variation range between the sun's azimuth and the orbital plane is divided into equal intervals to obtain a number of gear holding angles; Subtract the target rotation angle of the β-axis toward the sun from each of the gear holding angles in turn, and if the obtained deviation angle is not greater than the gear switching deviation angle, determine the current corresponding gear holding angle as the initial gear holding angle of the β-axis; wherein the gear switching deviation angle is set according to energy constraints and hysteresis loop width; Determining whether the current tracking error of the β-axis is greater than the gear switching deviation angle, and if not, controlling the β-axis to remain in the current gear; If so, the required gear holding angle is re-determined, and the β-axis is controlled to rotate to the target gear according to the operating state of the α-axis.

7. The method according to claim 6, characterized in that The gear switching deviation angle and the gear interval angle satisfy the following relationship: 2γ-δ≥H0 Wherein, γ is the gear switching deviation angle, δ is the gear interval angle, and H0 is the required minimum hysteresis loop width.

8. A control device for a large flexible dual-axis solar sail panel, characterized in that: The large flexible dual-axis sailboard includes an α-axis and a β-axis, wherein the α-axis is connected to the satellite body, and the β-axis is connected to the driving mechanism body of the α-axis; The device includes: A data acquisition unit, used to obtain the current rotation angles of the α-axis and the β-axis of the dual-axis sailboard; A target rotation angle calculation unit is used to calculate the target rotation angles of the α-axis and the β-axis aligned with the sun respectively by using the projection of the sun's position in the satellite body coordinate system and the orbit coordinate system; A tracking error calculation unit, used for respectively subtracting the current rotation angles of the α-axis and the β-axis from the target rotation angles of the α-axis and the β-axis aligned with the sun to obtain the tracking errors of the α-axis and the β-axis; An autonomous capture control unit, used to compare the current tracking errors of the α-axis and the β-axis with set thresholds respectively, and if the current tracking errors of the α-axis or the β-axis exceed the set threshold, autonomous capture is performed using the capture control strategy of the α-axis or the β-axis respectively; If the tracking errors of the α-axis and the β-axis both exceed the set threshold, the capture order of the α-axis and the β-axis in the dual-axis sailboard is determined according to the operating state of the α-axis, and the capture control strategies of the α-axis and the β-axis are used in turn according to the capture order to perform autonomous capture to achieve dual-axis decoupling control.

9. A computing device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to execute the method according to any one of claims 1 to 7.

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