Non-inductive coordination control method for quick zero passage of momentum wheel under redundant momentum wheel train

Abstract

The invention relates to the technical field of satellite attitude and orbit control, in particular to a non-inductive coordination control method for quick zero passage of a momentum wheel under a redundant momentum wheel train. The method comprises the following steps: firstly, interpreting the change trend of the rotating speed of the momentum wheel according to the change condition of the rotating speed of the momentum wheel; secondly, judging the zero-crossing state of the momentum wheel according to the rotating speed change trend and the actually measured rotating speed of the momentum wheel; and finally, based on the characteristic of zero motion of the momentum wheel set, applying zero-crossing compensation torque to the momentum wheel in a zero-crossing state to enable the momentum wheel to quickly pass through a rotating speed zero-crossing interval, and applying reverse compensation torque to other momentum wheels to enable the resultant torque of the compensation torque of the momentum wheel set to be zero. The rotating speed of the momentum wheel quickly passes through a zero-crossing interval through a method of increasing zero-crossing compensation torque, and the influence of zero-crossing of the rotating speed of the momentum wheel on the satellite attitude control precision is reduced. The method can be popularized and applied to all satellites with zero-crossing momentum wheel rotating speed and high attitude control precision requirements.

Description

Technical Field

[0001] This invention relates to the field of satellite attitude and orbit control technology, and in particular to a sensorless coordinated control method for rapid zero crossing of momentum wheels in a redundant momentum wheel system. Background Technology

[0002] High-orbit SAR satellites are equipped with large-aperture deployable antennas. The cumulative and fluctuating angular momentum caused by the satellite's gravity gradient torque and solar pressure torque is large. The momentum wheel experiences two zero-speed crossings within one orbital cycle. The control dead zone when the momentum wheel speed crosses zero will cause the satellite's attitude control accuracy to fail to meet the requirements. Summary of the Invention

[0003] The purpose of this invention is to provide a sensorless coordinated control method for the rapid zero-crossing of momentum wheels in a redundant momentum wheel system, thereby reducing the impact of the zero-crossing of momentum wheel speed on attitude control accuracy.

[0004] To achieve the above objectives, this invention provides a sensorless coordinated control method for rapid zero-crossing of momentum wheels in a redundant momentum wheel system, comprising the following steps:

[0005] S1. Determine the trend of the momentum wheel's rotational speed based on the changes in the momentum wheel's rotational speed;

[0006] S2. Determine the zero-crossing state of the momentum wheel by combining the trend of the rotational speed change and the measured rotational speed of the momentum wheel;

[0007] S3. Based on the zero-motion characteristic of the momentum wheel assembly, apply a zero-crossing compensation torque to the momentum wheel in the zero-crossing state to make it quickly pass through the zero-speed range. At the same time, apply a reverse compensation torque to the other momentum wheels to make the resultant torque of the compensation torque of the momentum wheel assembly zero.

[0008] Optionally, the trend of change in the momentum wheel speed can be categorized as increasing, decreasing, or remaining constant;

[0009] The momentum wheel's zero-crossing state is divided into positive zero-crossing, negative zero-crossing, and not crossing zero.

[0010] Optionally, the process for determining the trend of momentum wheel speed change is as follows:

[0011] S11. Calculate the difference between the current cycle momentum wheel speed and the previous cycle momentum wheel speed: deltaS = SP T -SP T-1 SP T SP is the rotational speed of the momentum wheel in this cycle. T-1 This represents the speed of the momentum wheel in the previous cycle.

[0012] S12. If deltaS is greater than the judgment threshold Hlmt, increment the speed change counter N by 1 and proceed to step S15; otherwise, proceed to step S13.

[0013] S13. If deltaS is less than the judgment threshold -Hlmt, decrement the speed change counter N by 1 and proceed to step S15; otherwise, proceed to step S14.

[0014] S14. If N is greater than 0, then N is decreased by 1; if N is less than 0, then N is increased by 1; otherwise, N remains unchanged.

[0015] S15. Based on the calculation results of steps S12 to S14, if N = Nlmt, then the momentum wheel speed change trend indicator Dir = 1, and the momentum wheel speed change trend is divided into increasing;

[0016] If N = -Nlmt, then the momentum wheel speed change trend indicator Dir = -1, and the momentum wheel speed change trend is either decreasing;

[0017] If N=0, then the trend indicator for the change in the speed of the momentum wheel is Dir=0, and the trend of the change in the speed of the momentum wheel is either stable or steady.

[0018] Optionally, the steps for determining the zero-crossing state of the momentum wheel are as follows:

[0019] S21. Calculate the speed S of the momentum wheel with the smallest absolute value of its rotational speed. Min and the corresponding momentum wheel number M Min ;

[0020] S22, If -M lmt Min <M lmt If the corresponding trend of the momentum wheel speed change is increasing, then the zero-crossing state of the momentum wheel is marked as positive zero crossing;

[0021] If -M lmt Min <M lmt If the corresponding trend of the momentum wheel speed change is decreasing, then the zero-crossing state indicator of the momentum wheel is a negative zero-crossing.

[0022] Otherwise, the momentum wheel's zero-crossing status is marked as not having crossed zero;

[0023] Among them, M lmt and -M lmt These are the upper and lower threshold values ​​for the zero-crossing range of the momentum wheel's rotational speed, respectively. Optionally, the steps for applying a zero-crossing compensation torque to the momentum wheel in the zero-crossing state are as follows:

[0024] S31. If the momentum wheel speed zero-crossing indicator is positive, then apply a positive control torque to the zero-crossing momentum wheel until the momentum wheel speed exceeds the upper limit threshold M of the zero-crossing interval. lmt ;

[0025] ​​If the momentum wheel speed zero-crossing indicator is a negative zero-crossing, then a negative control torque is applied to the zero-crossing momentum wheel until the momentum wheel speed exceeds the lower limit threshold of the zero-crossing interval -M. lmt ;

[0026] S32. Based on the momentum wheel installation matrix, calculate the compensation torque of other momentum wheels that do not cross zero, so that the resultant torque of the entire gear train is zero. The calculation method for the compensation torque of momentum wheels that do not cross zero is as follows:

[0027] T AC =-(C Aw ) T ·inv(C Aw (C Aw ) T )·C Zw ·T c

[0028] Among them, T AC C is a (n-1)×1 vector composed of the compensating torques of the other momentum wheels in the gear train that have not crossed zero (where n is the number of momentum wheels in the momentum wheel train). Zw For the mounting vector (3×1) of the zero-crossing momentum wheel, C Aw The matrix consisting of the installation vectors of the other momentum wheels that have not crossed zero is 3×(n-1) and is of full rank. Tc is the magnitude of the compensation torque (scalar) that the momentum wheels that have crossed zero need to provide. The superscript T indicates matrix transpose.

[0029] Optionally, the momentum wheel mounting matrix is ​​a 3×n matrix, where n is the number of momentum wheels.

[0030] The above-described technical solution of the present invention has the following advantages:

[0031] This invention provides a seamless coordinated control method for rapid zero-crossing of momentum wheels in a redundant momentum wheel system, comprising the following steps: First, the trend of momentum wheel speed change is determined based on the change in momentum wheel speed; second, the zero-crossing state of the momentum wheels is determined by combining the speed change trend and the measured speed of the momentum wheels; finally, based on the zero-motion characteristic of the momentum wheel group, a zero-crossing compensation torque is applied to the momentum wheel in the zero-crossing state to enable it to quickly pass through the zero-crossing speed range, while a reverse compensation torque is applied to the other momentum wheels to make the resultant torque of the compensation torque of the momentum wheel group zero. By increasing the zero-crossing compensation torque, the momentum wheel speed is made to quickly pass through the zero-crossing range, reducing the impact of the momentum wheel speed zero-crossing on the satellite attitude control accuracy. Attached Figure Description

[0032] The accompanying drawings are provided for illustrative purposes only, and the proportions and quantities of the components in the drawings may not be consistent with the actual product.

[0033] Figure 1 This is a flowchart illustrating the implementation of rapid zero-crossing control of the momentum wheel in an embodiment of the present invention;

[0034] Figure 2 This is the process for determining the trend of momentum wheel rotation speed change in this embodiment of the invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] like Figure 1 As shown in the figure, the present invention provides a sensorless coordinated control method for rapid zero crossing of momentum wheel in a redundant momentum wheel system, which is applied to a satellite with momentum wheel speed zero crossing condition. The method includes the following steps:

[0037] S1. Determine the trend of momentum wheel speed change based on the current and historical values ​​of momentum wheel speed. The trend of momentum wheel speed change is divided into three states: increasing, decreasing, and stable.

[0038] S2. Based on the trend of the momentum wheel speed, determine the zero-crossing state of the momentum wheel according to the current measured speed of the momentum wheel. The zero-crossing state of the momentum wheel is divided into three states: positive zero crossing (from negative speed to positive speed), negative zero crossing (from positive speed to negative speed), and not crossing zero.

[0039] S3. Based on the zero-crossing state judgment result of the momentum wheel in step S2, compensate the control torque of the momentum wheel so that the momentum wheel in the zero-crossing interval can quickly pass through the zero-crossing interval of the rotational speed, thereby reducing the disturbance of the static friction torque of the momentum wheel on the satellite attitude.

[0040] In one example, the process for determining the trend of momentum wheel speed change is as follows:

[0041] S11. Calculate the difference between the current cycle momentum wheel speed and the previous cycle momentum wheel speed: deltaS = SP T -SP T-1 SP T SP is the rotational speed of the momentum wheel in this cycle. T-1 This represents the speed of the momentum wheel in the previous cycle.

[0042] S12. If deltaS is greater than the judgment threshold Hlmt, increment the speed change counter N by 1 and proceed to step S15; otherwise, proceed to step S13.

[0043] S13. If deltaS is less than the judgment threshold -Hlmt, decrement the speed change counter N by 1 and proceed to step S15; otherwise, proceed to step S14.

[0044] S14. If N is greater than 0, then N is decreased by 1; if N is less than 0, then N is increased by 1; otherwise, N remains unchanged.

[0045] S15. Based on the calculation results of steps S12 to S14, if N = Nlmt, then the momentum wheel speed change trend indicator Dir = 1, and the momentum wheel speed change trend is divided into increasing;

[0046] If N = -Nlmt, then the momentum wheel speed change trend indicator Dir = -1, and the momentum wheel speed change trend is either decreasing;

[0047] If N=0, then the trend indicator for the change in the speed of the momentum wheel is Dir=0, and the trend of the change in the speed of the momentum wheel is either stable or steady.

[0048] In one example, the steps for determining the zero-crossing state of the momentum wheel are as follows:

[0049] S21. Calculate the speed S of the momentum wheel with the smallest absolute value of its rotational speed. Min and the corresponding momentum wheel number M Min ;

[0050] S22, If -M lmt Min <M lmt If the corresponding trend of the momentum wheel speed change is increasing, then the zero-crossing state of the momentum wheel is marked as positive zero crossing;

[0051] If -M lmt Min <M lmt If the corresponding trend of the momentum wheel speed change is decreasing, then the zero-crossing state indicator of the momentum wheel is a negative zero-crossing.

[0052] Otherwise, the momentum wheel's zero-crossing status is marked as not having crossed zero;

[0053] Among them, M lmt and -M lmt These are the upper and lower threshold values ​​for the zero-crossing interval of the momentum wheel speed, respectively.

[0054] In one example, the steps for applying a zero-crossing compensation torque to a momentum wheel that is in a zero-crossing state are as follows:

[0055] S31. If the momentum wheel speed zero-crossing indicator is positive, then apply a positive control torque to the zero-crossing momentum wheel until the momentum wheel speed exceeds the upper limit threshold M of the zero-crossing interval. lmt ;

[0056] ​​If the momentum wheel speed zero-crossing indicator is a negative zero-crossing, then a negative control torque is applied to the zero-crossing momentum wheel until the momentum wheel speed exceeds the lower limit threshold of the zero-crossing interval -M. lmt ;

[0057] S32. Based on the momentum wheel installation matrix (the installation matrix is ​​a 3×n matrix, where n is the number of momentum wheels), calculate the compensation torque of the other momentum wheels that have not crossed zero, so that the resultant torque of the entire gear train is zero. The calculation method for the compensation torque of the momentum wheels that have not crossed zero is as follows:

[0058] T AC =-(C Aw ) T ·inv(C Aw (C Aw ) T )·C Zw ·T c

[0059] Among them, T AC C is a (n-1)×1 vector composed of the compensating torques of the other momentum wheels in the gear train that have not crossed zero (where n is the number of momentum wheels in the momentum wheel train). Zw For the mounting vector (3×1) of the zero-crossing momentum wheel, C Aw The matrix consisting of the installation vectors of the other momentum wheels that have not crossed zero is 3×(n-1) and is of full rank. Tc is the magnitude of the compensation torque (scalar) that the momentum wheels that have crossed zero need to provide. The superscript T indicates matrix transpose.

[0060] In summary, satellites use momentum wheels for attitude control during normal operation. This invention proposes a seamless coordinated control method for rapid zero-crossing of momentum wheels in a redundant momentum wheel system. By increasing the zero-crossing compensation torque, the momentum wheel speed is rapidly passed through the zero-crossing range, reducing the impact of momentum wheel speed zero-crossing on the satellite's attitude control accuracy. First, the trend of momentum wheel speed change is determined based on the changes in momentum wheel speed. Second, the zero-crossing state of the momentum wheel is determined by combining the speed change trend and the measured speed of the momentum wheel. Finally, based on the zero-motion characteristic of the momentum wheel assembly, a zero-crossing compensation torque is applied to the momentum wheel in the zero-crossing state to rapidly pass through the speed zero-crossing range, while a reverse compensation torque is applied to the other momentum wheels to make the resultant torque of the momentum wheel assembly zero. This method can be extended to all satellites with momentum wheel speed zero-crossing conditions and high attitude control accuracy requirements.

[0061] It should be noted that how to compensate for the control torque to the momentum wheel is existing technology in this field and will not be elaborated here.

[0062] Any aspects not described in detail in this invention are common knowledge or existing technology in the field.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that not every embodiment contains only one independent technical solution, and in the absence of conflict between solutions, the various technical features mentioned in each embodiment can be combined in any way to form other implementation methods that can be understood by those skilled in the art.

[0064] Furthermore, without departing from the scope of the present invention, modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some of the technical features, shall not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sensorless coordinated control method for rapid zero-crossing of momentum wheels in a redundant momentum wheel system, characterized in that, Includes the following steps: S1. Determine the trend of the momentum wheel's rotational speed based on the changes in the momentum wheel's rotational speed; S2. Determine the zero-crossing state of the momentum wheel by combining the trend of the rotational speed change and the measured rotational speed of the momentum wheel; S3. Based on the zero-motion characteristic of the momentum wheel assembly, apply a zero-crossing compensation torque to the momentum wheel in the zero-crossing state to make it quickly pass through the zero-speed range. At the same time, apply a reverse compensation torque to the other momentum wheels to make the resultant torque of the compensation torque of the momentum wheel assembly zero.

2. The method according to claim 1, characterized in that: The trend of the momentum wheel speed change is divided into increasing, decreasing, and stable; The momentum wheel's zero-crossing state is divided into positive zero-crossing, negative zero-crossing, and not crossing zero.

3. The method according to claim 2, characterized in that: The process for determining the trend of momentum wheel speed change is as follows: S11. Calculate the difference between the current cycle momentum wheel speed and the previous cycle momentum wheel speed: deltaS = SP T -SP T-1 SP T SP is the rotational speed of the momentum wheel in this cycle. T-1 This represents the speed of the momentum wheel in the previous cycle. S12. If deltaS is greater than the judgment threshold Hlmt, increment the speed change counter N by 1 and proceed to step S15; otherwise, proceed to step S13. S13. If deltaS is less than the judgment threshold -Hlmt, decrement the speed change counter N by 1 and proceed to step S15; otherwise, proceed to step S14. S14. If N is greater than 0, then N is decreased by 1; if N is less than 0, then N is increased by 1; otherwise, N remains unchanged. S15. Based on the calculation results of steps S12 to S14, if N = Nlmt, then the momentum wheel speed change trend indicator Dir = 1, and the momentum wheel speed change trend is divided into increasing; If N = -Nlmt, then the momentum wheel speed change trend indicator Dir = -1, and the momentum wheel speed change trend is either decreasing; If N=0, then the trend indicator for the change in the speed of the momentum wheel is Dir=0, and the trend of the change in the speed of the momentum wheel is either stable or steady.

4. The method according to claim 2, characterized in that: The steps for determining the zero-crossing state of the momentum wheel are as follows: S21. Calculate the speed S of the momentum wheel with the smallest absolute value of its rotational speed. Min and the corresponding momentum wheel number M Min ; S22, If -M lmt Min <M lmt If the corresponding trend of the momentum wheel speed change is increasing, then the zero-crossing state of the momentum wheel is marked as positive zero crossing;​ If -M lmt Min <M lmt If the corresponding trend of the momentum wheel speed change is decreasing, then the zero-crossing state indicator of the momentum wheel is a negative zero-crossing.​ Otherwise, the momentum wheel's zero-crossing status is marked as not having crossed zero; Among them, M lmt and -M lmt These are the upper and lower threshold values ​​for the zero-crossing interval of the momentum wheel speed, respectively.

5. The method according to claim 2, characterized in that: The steps for applying a zero-crossing compensation torque to the momentum wheel in a zero-crossing state are as follows: S31. If the momentum wheel speed zero-crossing indicator is positive, then apply a positive control torque to the zero-crossing momentum wheel until the momentum wheel speed exceeds the upper limit threshold M of the zero-crossing interval. lmt ; If the momentum wheel speed zero-crossing indicator is a negative zero-crossing, then a negative control torque is applied to the zero-crossing momentum wheel until the momentum wheel speed exceeds the lower limit threshold of the zero-crossing interval -M. lmt ; S32. Based on the momentum wheel installation matrix, calculate the compensation torque of other momentum wheels that do not cross zero, so that the resultant torque of the entire gear train is zero. The calculation method for the compensation torque of momentum wheels that do not cross zero is as follows: T AC =-(C Aw ) T ·inv(C Aw (C Aw ) T )·C Zw ·T c Among them, T AC C is a (n-1)×1 vector composed of the compensating torques of the other momentum wheels in the gear train that have not crossed zero (where n is the number of momentum wheels in the momentum wheel train). Zw For the mounting vector (3×1) of the zero-crossing momentum wheel, C Aw The matrix consisting of the installation vectors of the other momentum wheels that have not crossed zero is 3×(n-1) and is of full rank. Tc is the magnitude of the compensation torque (scalar) that the momentum wheels that have crossed zero need to provide. The superscript T indicates matrix transpose.

6. The method according to claim 5, characterized in that: The momentum wheel installation matrix is ​​a 3×n matrix, where n is the number of momentum wheels in the momentum wheel assembly.

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