A high-precision orbit control method based on constant acceleration

Abstract

The application discloses a high-precision orbit control method based on constant acceleration, which comprises the following steps: S1, calculating a constant acceleration control target; S2, calculating a constant jet time of a small thruster through trial jet; S3, calculating a real-time jet time compensation amount according to a real-time measured acceleration; and S4, executing jetting and stopping the small thruster from jetting after a time. The application can adapt to any mass and thrust deviation condition through trial jet calibration in orbit, and the small thruster is used to compensate the thrust, so that the large thruster can continuously work.

Description

Technical Field

[0001] This invention relates to the field of space orbit control execution, and more specifically to a high-precision orbit control method based on constant acceleration. Background Technology

[0002] With the development of aerospace technology, the missions of spacecraft in orbit have become increasingly diversified. Spacecraft in orbit need to maintain a stable attitude and orbit to ensure normal operation, making large-scale orbital maneuver control an essential function of spacecraft.

[0003] Currently, large-scale orbital maneuvers by aircraft are mostly controlled by ground-based tracking and control stations. These stations control the timing and duration of jet propulsion to achieve precise orbital control. However, autonomous large-scale orbital maneuvers are much more difficult, requiring not only accurate navigation and stable attitude but also precise orbital execution control.

[0004] While incremental speed shutdown ensures that the actual speed increment generated by the aircraft aligns with the orbital control strategy, deviations in aircraft mass, thrust magnitude, and direction can cause the orbital control execution to deviate from the original control objective. Therefore, a control execution method that can compensate for these deviations is needed. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that current aircraft require high precision in orbital control when performing large-scale orbital maneuvers, and are prone to deviations.

[0006] To achieve the above objectives, this invention proposes a high-precision orbit control method based on constant acceleration, comprising the following steps:

[0007] S1. Calculate the constant acceleration control target;

[0008] S2. Calculate the constant jet time t of the small thruster through test jetting. p1 ;

[0009] S3. Calculate the real-time jet time compensation amount t based on the real-time measured acceleration. p2 ;

[0010] S4, execute the jet and at time t p Then the small thruster stops jetting, where t p =t p1 +t p2 .

[0011] Preferably, step S1 further includes the following steps:

[0012] S11. Calculate the required jet duration T. pq ;

[0013] S12. Based on the required jet duration, design the constant acceleration control target for the aircraft: Among them, a acc Let Δv be the ideal constant acceleration of the aircraft, and Δv be the velocity increment calculated by the aircraft strategy.

[0014] Preferably, the required jetting duration is Where M s For the mass of the aircraft, I sp For the specific impulse of the thruster, F s For the nominal thrust of all small thrusters, F b This refers to the nominal thrust of a large thruster.

[0015] Preferably, step S2 specifically involves: taking the strategy calculation trajectory change point as the center, halving the jetting time, and at a distance of 0.5T from the jetting moment... pq The jet propulsion begins; an initial test jet propulsion lasts 10 seconds, with only the large thruster activated. The average acceleration over 10 seconds is calculated as 'a' by measuring and accumulating the acceleration. s10 Next, continue the test jetting for 10 seconds, with the large thruster engaged and the small thruster maintained at half-jet. The average acceleration over these 10 seconds is calculated as 'a' by measuring and summing the accelerations. s20 Therefore, the constant jet time of a small thruster is: T c To control the cycle.

[0016] Preferably, step S3 specifically involves: the target velocity increment value being: Δv t =a acc ·Δt, where Δt is the increased jet duration;

[0017] The current speed increment is: a n =a n-1 +a b ;Δv n =a n ·T c , where a b For the measured acceleration, a n This refers to the total actual acceleration increment obtained by accumulating the accelerations.

[0018] The jet time compensation for a small thruster is:

[0019] Preferably, t p The upper limit is the control period, and the lower limit is 0.

[0020] Preferably, the large thruster adopts a speed increment shutdown method, where the cumulative acceleration increment Δv of the aircraft is... nWhen the thrust is greater than or equal to Δv, the large thruster stops jetting.

[0021] Preferably, when using a large thruster, the vector direction of the large thruster is rotated to be consistent with the direction of the velocity increment vector. At this time, the jet propulsion of the large thruster needs to be stopped by judging the relationship between the velocity increment of a single axis and the magnitude of the total velocity increment.

[0022] This invention corrects acceleration by changing the jetting time of a small thruster in each control cycle, ensuring that the aircraft's acceleration matches the design value. Compared with existing technologies, this invention has the following advantages:

[0023] (1) The present invention can perform test jet calibration in orbit and can adapt to any deviation in mass and thrust;

[0024] (2) The present invention compensates for thrust by using a small thruster, so that the large thruster can work continuously.

[0025] (3) The present invention is the execution control of track control, which is independent of the strategy calculation process. Attached Figure Description

[0026] Figure 1 This is a flowchart of a high-precision track control method based on constant acceleration according to the present invention;

[0027] Figure 2 This is a schematic diagram of the aircraft and thruster in this invention;

[0028] Figure 3 This is a graph showing the time-varying constant acceleration and mass of the aircraft. Detailed Implementation

[0029] The technical solutions, structural features, achieved objectives, and effects of the present invention will be described in detail below with reference to the accompanying drawings in the embodiments of the present invention.

[0030] It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions. They are only used to facilitate and clarify the purpose of illustrating the embodiments of the present invention, and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationship, or adjustments to the size should still fall within the scope of the technical content disclosed in the present invention, provided that they do not affect the effects and objectives that the present invention can produce.

[0031] It should be noted that, in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only the expressly listed elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0032] A high-precision trajectory control method based on constant acceleration corrects acceleration by changing the jetting time of each small thruster control cycle, ensuring the aircraft's acceleration matches the design value. This invention is based on using a half-jet mode for small thrusters and a full-jet mode for large thrusters. In the half-jet mode, the thruster's jetting time is half the control cycle, while in the full-jet mode, the thruster maintains jetting throughout the entire control cycle. Based on this design, the jetting time is adjusted, specifically, as follows... Figure 1 As shown, the method includes the following steps:

[0033] S1. Calculate the constant acceleration control target, which includes the following steps:

[0034] S11. Calculate the required jet duration;

[0035] Assume the nominal thrust of the small thruster (i.e., the thrust generated if the small thruster is always on within a control cycle) is F. s Then, a control cycle T c The actual equivalent thrust generated by the jet propulsion of this small thruster is 0.5F. s It should be noted that F here s This refers to the nominal thrust of all small thrusters, such as in Figure 2 In the scenario shown, two small thrusters are included, and the nominal thrust of the two small thrusters is F. s Correspondingly, the actual equivalent thrust generated by these two small thrusters within one control cycle is 0.5F. s The nominal thrust of a large thruster is F. b The small thruster and the large thruster have the same thrust direction, therefore one control cycle T c The actual total nominal thrust is (0.5F) s +F b ).

[0036] If the speed increment calculated by the aircraft strategy (i.e., the process design to achieve a certain desired result) is Δv, then the required jet propulsion time is... Where M s For the mass of the aircraft, I sp For the specific impulse of the thruster;

[0037] S12. Based on the required jet duration, design the constant acceleration control target for the aircraft: a acc The ideal constant acceleration for an aircraft;

[0038] S2. Calculate the constant jetting time of the small thruster through test jetting;

[0039] Centered on the strategic trajectory change point, and for ease of calculation, the jet time is halved, with the jet time 0.5T away from the jet moment. pq The jet propulsion begins; an initial test jet propulsion lasts 10 seconds, during which only the large thruster is activated. The average acceleration over 10 seconds is calculated as 'a' by measuring and accumulating the acceleration. s10 Next, continue the test jetting for 10 seconds, with the large thruster engaged and the small thruster maintained at half-jet. The average acceleration over these 10 seconds is calculated as 'a' by measuring and summing the accelerations. s20 Therefore, in one control cycle T c The formula for calculating the constant jet time of a small thruster is:

[0040]

[0041] S3. Calculate the real-time jet time compensation based on the real-time measured acceleration;

[0042] Due to the prolonged jet propulsion process, the mass of the aircraft changes, and the trend of this change is as follows: Figure 3 As shown, since the constant acceleration remains constant, additional compensation for the thrust is required based on the real-time acceleration measurement results. The calculation process is as follows;

[0043] The target velocity increment is: Δv t =a acc ·Δt, where Δt is the increased jet duration.

[0044] The current speed increment is (accumulated from the start of the jet): a n =a n-1 +a b ;Δv n =a n ·T c , where a b For the measured acceleration, a n This is the total actual acceleration increment obtained by accumulating the accelerations. The jet time compensation for a small thruster is:

[0045] S4, jet execution and jet completion processing;

[0046] The jetting time t of the small thruster in each control cycle can be obtained from steps S2 and S3. p Specifically: t p =t p1 +t p2 , and t p The upper limit is T c The lower limit is 0.

[0047] Large thrusters employ a speed increment shutdown method, where the cumulative acceleration increment Δv of the aircraft is reduced. n When ≥‖Δv‖, the thrusters (including large and small thrusters) stop jetting.

[0048] Preferably, since the speed increment Δv calculated by the strategy is the speed increment of the three axes, when using a large thruster, the vector direction of the large thruster is turned to be consistent with the direction of the speed increment vector. Thus, it is possible to determine whether the jet needs to be stopped simply by judging the relationship between the speed increment of a single axis and the magnitude of the total speed increment.

[0049] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A high-precision track control method based on constant acceleration, characterized in that, Includes the following steps: S1. Calculate the constant acceleration control target, i.e., the ideal constant acceleration. S2, combined with the calculated ideal constant acceleration The constant jet time of a small thruster was calculated through test jetting. S3, through ideal constant acceleration Calculate the target velocity increment, and then calculate the real-time jet time compensation based on the real-time measured acceleration. ; S4, execute jet propulsion and in time Then the small thruster stopped jetting, among which, ; Step S1 includes: S11. Calculate the required jet duration. S12. Based on the required jet duration, design the constant acceleration control target for the aircraft: In the formula, For the ideal constant acceleration of the aircraft, The velocity increment is calculated for the aircraft strategy.

2. The high-precision track control method based on constant acceleration as described in claim 1, characterized in that, The required jet duration is ,in For the mass of the aircraft, For the specific impulse of the thruster, The nominal thrust for all small thrusters, This refers to the nominal thrust of a large thruster.

3. The high-precision track control method based on constant acceleration as described in claim 2, characterized in that, Step S2 specifically involves: centering on the strategy calculation trajectory change point, halving the jet propulsion time, and at a distance of 0.5 from the jet propulsion moment... The jet propulsion begins; an initial test jet propulsion lasts 10 seconds, with only the large thruster activated. The average acceleration over 10 seconds is calculated by measuring and accumulating the acceleration. Next, continue testing the jet propulsion for 10 seconds, with the large thruster engaged and the small thruster maintained at half-thrust. The average acceleration over these 10 seconds was calculated by measuring and summing the acceleration values. Therefore, the constant jet time of a small thruster is: · +0.5 , To control the cycle.

4. The high-precision track control method based on constant acceleration as described in claim 3, characterized in that, Specifically, step S3 involves: the target velocity increment value is: ,in To increase the jet duration; the current speed increment is: ; ,in, For the measured acceleration, The total actual acceleration increment is obtained by accumulating the accelerations; the jet time compensation for a small thruster is: .

5. The high-precision track control method based on constant acceleration as described in claim 1, characterized in that, The upper limit is the control period, and the lower limit is 0.

6. The high-precision track control method based on constant acceleration as described in claim 4, characterized in that, Large thrusters employ a speed increment shutdown method, where the cumulative acceleration of the aircraft increases by a certain amount. At that time, the large thruster stopped jetting air.

7. The high-precision track control method based on constant acceleration as described in claim 6, characterized in that, When using a large thruster, the vector direction of the large thruster is turned to be consistent with the direction of the velocity increment vector. At this time, the jet propulsion of the large thruster needs to be stopped by judging the relationship between the velocity increment of a single axis and the magnitude of the total velocity increment.

Images