Spatial non-conservative force measuring system and measuring method for spacecraft in on-orbit flight

Abstract

The invention provides a space non-conservative force measuring system and method in spacecraft on-orbit flight, and the system comprises a space standard force source which is used for generating a standard force in a space environment and applying the standard force to a stress mechanism; the stress mechanism is used for receiving standard force and generating motion state change; the motion state measurement mechanism is used for measuring the motion state change of the stress mechanism under the action of the standard force or the external space non-conservative force and outputting a measurement signal; the controller is configured to obtain the motion state change of the stress mechanism under the action of standard force, establish the corresponding relation between the motion state change and the measurement signal, measure the current measurement signal of the stress mechanism through the motion state measurement mechanism when the spatial non-conservative force is measured, and measure the spatial non-conservative force according to the corresponding relation and the current measurement signal. The current motion state change is obtained, and according to the current motion state change and the mass information of the stress mechanism, the space non-conservative force acting on the spacecraft is obtained through calculation according to the kinematics law.

Description

Technical Field

[0001] The present application mainly relates to the field of aerospace technology, and in particular to a space non-conservative force measurement system and method for a spacecraft in orbit. Background Art

[0002] With the rapid development of space science and technology in recent years, the precise measurement of the forces acting on spacecraft during in-orbit flight has shown a more extensive and important value in the field of space science and aerospace engineering. It is the premise and guarantee for achieving precise attitude and orbit determination and ultra-quiet and ultra-stable control of spacecraft, and can also provide new methods and means for conducting space science research. The precise measurement of the forces acting on spacecraft during in-orbit flight will provide technical support for the successful implementation of important space missions such as the measurement of the Earth's gravity field, the detection of gravitational waves in space, and the verification of relativistic effects.

[0003] When a spacecraft is moving in space, it is affected by forces from sources such as solar pressure, atmospheric drag, cosmic rays, and the gravity of celestial bodies. These forces can be divided into two categories: conservative forces and non-conservative forces. Forces whose work is independent of the path are called conservative forces. In space, conservative forces mainly include the gravitational forces of the earth and other celestial bodies on spacecraft, which can usually be obtained through accurate modeling. Non-conservative forces, on the other hand, are related to the path. In space, non-conservative forces include the forces of factors such as solar pressure, atmospheric drag, and cosmic rays on spacecraft. They have the characteristics of diverse sources, small force values, and continuous changes over time. How to measure them in real time with high precision is an important issue that needs to be solved in the aerospace field. At present, the measurement of non-conservative forces in space is mainly carried out by onboard accelerometers carried by spacecraft. Onboard accelerometers measure the acceleration changes of spacecraft during in-orbit flight and calculate the forces they are subject to in combination with information such as the mass distribution of the spacecraft. As an acceleration measurement instrument, onboard accelerometers need to be calibrated before measurement. At present, the calibration of satellite-borne accelerometers is mainly carried out by combining ground calibration before launch with indirect calibration on orbit, and there is no accurate direct on-orbit calibration method. Because it is impossible to calibrate the space non-conservative force measurement device in real time on orbit, the accuracy and real-time performance of the measurement cannot be guaranteed, which makes it difficult to meet the needs of some advanced space science missions and aerospace engineering applications, and has become a difficult problem that needs to be solved urgently in the aerospace field. Summary of the invention

[0004] The technical problem to be solved by the present application is that it is impossible to perform on-orbit real-time calibration of a space non-conservative force measurement device, and thus it is impossible to ensure the accuracy and real-time performance of the measurement.

[0005] To solve the above technical problems, the present application provides a system for measuring space non-conservative forces during the on-orbit flight of a spacecraft, including: a space standard force source for generating a standard force in a space environment and applying the standard force to a force-receiving mechanism, where the direction and magnitude of the standard force are known; a force-receiving mechanism for receiving the standard force and generating a change in the motion state, where the mass and mass distribution of the force-receiving mechanism are known; a motion state measuring mechanism for measuring the change in the motion state of the force-receiving mechanism under the action of the standard force or external space non-conservative forces and outputting a measurement signal; a controller configured to: obtain, through theoretical calculation, the change in the motion state of the force-receiving mechanism under the action of the standard force, establish a correspondence between the change in the motion state and the measurement signal, and, when measuring the space non-conservative force, measure the current measurement signal of the force-receiving mechanism through the motion state measuring mechanism, obtain the current change in the motion state according to the correspondence and the current measurement signal, and calculate, according to the current change in the motion state and the mass information of the force-receiving mechanism, the space non-conservative force acting on the spacecraft using the kinematic law.

[0006] In an embodiment of the present application, the change in the motion state includes the acceleration response of the force-receiving mechanism.

[0007] In an embodiment of the present application, the force-receiving mechanism includes a spacecraft platform and / or a part of the spacecraft platform.

[0008] In an embodiment of the present application, the force-receiving mechanism includes a payload inside the spacecraft and / or a part of the payload. The payload is in a flight state in the spacecraft where it is not affected by external space non-conservative forces, and the motion state measuring mechanism is arranged on the spacecraft platform.

[0009] In an embodiment of the present application, the payload is in an inertial flight state.

[0010] In an embodiment of the present application, the spacecraft platform generates a force on the payload in any one of the ways of magnetic levitation, electrostatic levitation, wire suspension, or low-stiffness elastic connection.

[0011] In an embodiment of the present application, the motion state measuring mechanism includes an on-board accelerometer, and the measurement signal includes an acceleration change.

[0012] In an embodiment of the present application, the motion state measuring mechanism includes a gyroscope, a star sensor, or a sun sensor, and the measurement signal includes a rotational acceleration change or a pointing angle change.

[0013] In an embodiment of the present application, the motion state measuring mechanism includes an inter-satellite or satellite-ground ranging system, and the measurement signal includes a change in the position of the spacecraft.

[0014] In an embodiment of the present application, the motion state measurement mechanism includes a relative quantity measurement device based on the principles of static electricity, electromagnetic, or laser interference, and the measurement signal includes the relative distance and relative angle changes between the force-bearing mechanism and the spacecraft or the carried components.

[0015] In an embodiment of the present application, the motion state measurement mechanism includes a Doppler measurement device based on the Doppler effect, and the measurement signal includes the relative velocity change of the spacecraft.

[0016] The present application also proposes a method for measuring the space non-conservative force during the on-orbit flight of a spacecraft to solve the above technical problems, including:

[0017] Step S11: Generate a standard force by a space standard force source and apply the standard force to the force-bearing mechanism;

[0018] Step S12: Obtain the change in the motion state of the force-bearing mechanism under the action of the standard force through theoretical calculation;

[0019] Step S13: Measure the measurement signal of the force-bearing mechanism through the motion state measurement mechanism;

[0020] Step S14: Establish the correspondence between the change in the motion state and the measurement signal;

[0021] Step S15: When measuring the space non-conservative force, measure the current measurement signal of the force-bearing mechanism through the motion state measurement mechanism;

[0022] Step S16: Obtain the current change in the motion state according to the correspondence and the current measurement signal;

[0023] Step S17: Calculate the space non-conservative force acting on the spacecraft by using the kinematic law according to the current change in the motion state and the mass information of the force-bearing structure.

[0024] In an embodiment of the present application, it further includes: in response to a calibration instruction, repeatedly execute steps S11 to S13 a predetermined number of times, and adjust one or more of the action point, action direction, action magnitude, and action time of the standard force during each cycle, and execute step S14 after reaching the predetermined number of times.

[0025] In an embodiment of the present application, in step S11, the range of the change in the motion state of the force-bearing mechanism under the action of the standard force is greater than the range of the change in the motion state of the spacecraft when it is subjected to a non-conservative force.

[0026] In an embodiment of the present application, step S11 includes: applying one or more of the standard forces to one or more surfaces of the force-receiving mechanism, causing a change in the motion state of the force-receiving mechanism with six degrees of freedom.

[0027] In an embodiment of the present application, step S12 includes: the standard force is a unidirectional force, the acting point of the standard force is on the surface of the force-receiving mechanism, and the acting direction of the standard force is always perpendicular to the surface and outward; the force-receiving mechanism has two opposite surfaces, the standard force is applied to the two opposite surfaces, generating two couples of forces parallel to the first axis, the two couples of forces generate a first moment about the second axis and a second moment about the third axis on the force-receiving mechanism, and cause a first angular acceleration change of the force-receiving mechanism about the second axis and a second angular acceleration change about the third axis, and the acceleration response of the force-receiving mechanism includes the first angular acceleration change and the second angular acceleration change, where the first axis, the second axis, and the third axis are perpendicular to each other.

[0028] In an embodiment of the present application, in step S12, the change in the motion state includes the acceleration response of the force-receiving mechanism, and the change in the motion state is related to the characteristics of the standard force and the mass of the force-receiving mechanism.

[0029] In an embodiment of the present application, in step S13, the measurement signal is related to the measurement range and resolution of the motion state measurement mechanism.

[0030] In an embodiment of the present application, it further includes: in response to a measurement instruction, performing steps S15 to S17.

[0031] In an embodiment of the present application, step S15 includes:

[0032] Step S151: When the force-receiving mechanism is subjected to the space non-conservative force, the motion state measurement mechanism measures the current measurement signal of the force-receiving mechanism;

[0033] Step S152: When the force-receiving mechanism is not subjected to the space non-conservative force, the spacecraft platform is subjected to the space non-conservative force, and a relative motion change occurs between the force-receiving mechanism and the spacecraft platform, and the motion state measurement mechanism measures the current measurement signal corresponding to the relative motion change.

[0034] The space non-conservative force measurement system and method of the present application provide a space standard force source. By applying a standard force to the force-bearing mechanism through the space standard force source to cause a change in its motion state, at the same time, a motion state measurement mechanism is used to obtain the measurement signal of the force-bearing mechanism, and the corresponding relationship between the change in motion state and the measurement signal is established, so as to realize the calibration process of the space non-conservative force measurement system. Further, when measuring the space non-conservative force, according to this corresponding relationship and the mass information of the force-bearing mechanism, the space non-conservative force acting on the spacecraft is calculated using the kinematic law. The calibrated space non-conservative force measurement system can directly and accurately measure the space non-conservative force without post-processing of the measurement data, and its measurement has real-time performance, which is beneficial to realizing the real-time control of the attitude and orbit of the spacecraft, and can adapt to a wide range of force values of the space non-conservative force, with a wide range of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are provided to further understand the present application. They are incorporated and constitute a part of the present application. The drawings illustrate the embodiments of the present application and, together with this specification, serve to explain the principles of the present application. In the drawings:

[0036] Figure 1 is a block diagram of the space non-conservative force measurement system according to an embodiment of the present application;

[0037] Figure 2 is a schematic diagram of a scenario including the force-bearing mechanism in the space non-conservative force measurement system according to an embodiment of the present application;

[0038] Figure 3 is an exemplary flowchart of the space non-conservative force measurement method according to an embodiment of the present application;

[0039] Figure 4 is a schematic diagram of the calibration process in the space non-conservative force measurement method according to an embodiment of the present application;

[0040] Figure 5A is used to illustrate the action of the standard force acting on the force-bearing mechanism in the space non-conservative force measurement method according to an embodiment of the present application;

[0041] Figure 5B is used to illustrate the change in the motion state of the force-bearing mechanism in the space non-conservative force measurement method according to an embodiment of the present application;

[0042] Figure 6 is a schematic diagram of the measurement process in the space non-conservative force measurement method according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the figures represent the same structure or operation.

[0044] As shown in the present application, unless the context clearly indicates an exceptional situation, words such as "a", "an", "one", and / or "the" are not specifically singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of the clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0045] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps described in these embodiments do not limit the scope of the present application. At the same time, it should be understood that for the sake of convenience in description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the said technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0046] In the description of the present application, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal", and "top, bottom" are usually based on the orientation or positional relationships shown in the accompanying drawings. It is only for the convenience of describing the present application and simplifying the description. Without contrary instructions, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the protection scope of the present application; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0047] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Without additional statements, these terms have no special meanings, and thus should not be construed as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant according to his or her judgment, and their detailed meanings are described in the relevant parts of this description. In addition, it is required to understand this application not only through the actual terms used, but also through the meanings implied by each term.

[0048] Flowcharts are used in this application to illustrate the operations performed by the systems according to the embodiments of this application. It should be understood that the operations before or below do not necessarily need to be executed precisely in order. On the contrary, they can be executed in reverse order or simultaneously. At the same time, other operations can be added to these processes, or one or more steps can be removed from these processes.

[0049] The space non-conservative force measurement system and measurement method during the on-orbit flight of the spacecraft of this application can be applied to any type of spacecraft, including but not limited to satellites. In this specification, a spacecraft includes a spacecraft platform, the components carried thereon, etc.

[0050] Figure 1 is a block diagram of the space non-conservative force measurement system according to an embodiment of this application. Refer to Figure 1 As shown in the figure, the space non-conservative force measurement system 100 includes a space standard force source 110, a force-receiving mechanism 120, a motion state measurement mechanism 130, and a controller 140. Among them, the space standard force source 110 is used to generate a standard force in the space environment and apply the standard force to the force-receiving mechanism. In metrology, a standard force source is carried by a corresponding device to provide a reference and standard for force value measurement, and its function is to generate a standard force value. The space standard force source 110 in this application corresponds to the space environment and can be carried by a certain device located in the spacecraft. Its function is to generate a standard force with known magnitude and direction acting on the spacecraft or its components in the space environment. The space standard force source 110 uses specific physical mechanisms, including but not limited to gravitational force, electrostatic force, electromagnetic force, particle collision pressure, light pressure, etc., or a combination of the above physical methods, to generate a standard force with a certain direction and magnitude. The standard force can be traced back to the International System of Units. Usually, the amplitude, action point or action area, and action time of the standard force output by the space standard force source 110 can be adjusted and controlled.

[0051] The force-receiving mechanism 120 is configured to receive the standard force output by the space standard force source 110 and generate a change in the motion state. The mass and mass distribution of the force-receiving mechanism 120 are known. This change in the motion state can be determined through measurement. The force-receiving mechanism 120 generally has stable mechanical properties. The force-receiving mechanism 120 can have a large rigidity, and it does not deform or the deformation is negligible under the action of the standard force. When under the action of the standard force, the overall motion state of the force-receiving mechanism 120 changes, such as a change in the rotational or translational state. When the rigidity of the force-receiving mechanism 120 is small, it may deform under the action of the standard force, and at the same time, it may be accompanied by a change in the overall motion state, such as translation, rotation, torsion, or swing of some structures.

[0052] In some embodiments, the change in the motion state of the force-receiving mechanism 120 includes the acceleration response of the force-receiving mechanism 120. The acceleration response includes the magnitude and direction of the acceleration, etc.

[0053] The motion state measurement mechanism 130 is configured to measure the change in the motion state of the force-receiving mechanism 120 under the action of the standard force or the external space non-conservative force, and output a measurement signal.

[0054] In some embodiments, the force-receiving mechanism 120 includes a spacecraft platform, and / or, a part of the spacecraft platform. According to these embodiments, the motion state measurement mechanism 130 is installed on the spacecraft platform, the motion state measurement mechanism 130 moves synchronously with the force-receiving mechanism 120, and the motion state measurement mechanism 130 can use the measurement of its own motion state change as the motion state change of the force-receiving mechanism 120.

[0055] In some embodiments, the force-receiving mechanism 120 includes a payload inside the spacecraft, and / or, a part of the payload. The payload is in a flight state where it is not affected by the external space non-conservative force in the spacecraft, and the motion state measurement mechanism 130 is arranged on the spacecraft platform. According to these embodiments, when the spacecraft platform is subjected to the space non-conservative force, a relative motion occurs between the force-receiving mechanism 120 and the motion state measurement mechanism 130, and the motion state measurement mechanism 130 can measure the change in the motion state of the force-receiving mechanism 120 in real time.

[0056] Figure 2 It is a schematic diagram of a scenario including the force-receiving mechanism in the space non-conservative force measurement system according to an embodiment of the present application. As Figure 2, the force-bearing mechanism 120 is a payload component in the spacecraft platform 210 or a part of the payload component, and it is in a flight state in the spacecraft where it is not affected by external non-conservative forces in space, such as in an inertial flight state. The spacecraft platform 210 can exert a force on the payload component serving as the force-bearing mechanism 120 in any of the ways of magnetic levitation, electrostatic levitation, wire suspension, or low-stiffness elastic connection. When the force-bearing mechanism 120 is a payload component on the spacecraft, to prevent excessive relative displacement between the force-bearing mechanism 120 and the spacecraft, the possible displacement range of the force-bearing mechanism 120 relative to the spacecraft platform 210 can be restricted, and at the same time, the relative position between the two can be adjusted and controlled by means including electromagnetic force, spring elastic force, and thin wire tension.

[0057] As Figure 2 shown, the motion state measurement mechanism 130 is disposed on the spacecraft platform 210. When the spacecraft platform 210 is subjected to external non-conservative forces in space, the motion state measurement mechanism 130 and the force-bearing mechanism 120 undergo relative motion, and the motion state measurement mechanism 130 is disposed around the force-bearing mechanism 120, and the relative motion of the force-bearing mechanism 120 can be measured by a non-contact method, such as an optical method.

[0058] In some embodiments, the motion state measurement mechanism 130 includes an on-board accelerometer, and the corresponding measurement signal is the acceleration change.

[0059] In some embodiments, the motion state measurement mechanism 130 includes a gyroscope, a star sensor, or a sun sensor, and the measurement signal is the rotational acceleration change or the pointing angle change.

[0060] In some embodiments, the motion state measurement mechanism 130 includes an inter-satellite or satellite-ground ranging system, and the measurement signal is the position change of the spacecraft.

[0061] In some embodiments, the motion state measurement mechanism 130 includes a relative quantity measurement device based on the principles of electrostatics, electromagnetism, or laser interference, and the measurement signal is the relative distance and relative angle change between the force-bearing mechanism 120 and the spacecraft or the payload component.

[0062] In some embodiments, the motion state measurement mechanism 130 includes a Doppler measurement device based on the Doppler effect, and the measurement signal is the relative velocity change of the spacecraft.

[0063] According to the above embodiments, the motion state measurement mechanism 130 can include one or any combination of the above-mentioned on-board accelerometer, gyroscope, star sensor, sun sensor, relative quantity measurement device, and Doppler measurement device, and obtain the corresponding measurement signals simultaneously.

[0064] Reference Figure 1, the controller 140 in the space non-conservative force measurement system 100 is configured to: obtain the change in the motion state of the force-bearing mechanism 120 under the action of a standard force through theoretical calculation, establish the correspondence between the change in the motion state and the measurement signal, and when measuring the space non-conservative force, measure the current measurement signal of the force-bearing mechanism through the motion state measurement mechanism 130, obtain the current change in the motion state according to the correspondence and the current measurement signal, and calculate the space non-conservative force acting on the spacecraft using the kinematic law based on the current change in the motion state and the mass information of the force-bearing structure.

[0065] The present application also proposes a method for measuring space non-conservative force, which can be executed by the space non-conservative force measurement system 100 described above. The working mode of the controller 140 in the space non-conservative force measurement system 100 will be described below in conjunction with the description of the method for measuring space non-conservative force.

[0066] Figure 3 is an exemplary flowchart of the method for measuring space non-conservative force according to an embodiment of the present application. Refer to Figure 3 , the method for measuring space non-conservative force in this embodiment includes the following steps:

[0067] Step S11: Generate a standard force by the space standard force source 110 and apply the standard force to the force-bearing mechanism 120;

[0068] Step S12: Obtain the change in the motion state of the force-bearing mechanism 120 under the action of the standard force through theoretical calculation;

[0069] Step S13: Measure the measurement signal of the force-bearing mechanism 120 through the motion state measurement mechanism 130;

[0070] Step S14: Establish the correspondence between the change in the motion state and the measurement signal;

[0071] Step S15: When measuring the space non-conservative force, measure the current measurement signal of the force-bearing mechanism 120 through the motion state measurement mechanism 130;

[0072] Step S16: Obtain the current change in the motion state according to the correspondence and the current measurement signal;

[0073] Step S17: Calculate the space non-conservative force acting on the spacecraft using the kinematic law based on the current change in the motion state and the mass information of the force-bearing structure 120.

[0074] The above steps S11 - S17 will be described in detail below with reference to the accompanying drawings.

[0075] The space non-conservative force measurement system of the present application can perform two tasks or processes, namely calibration and measurement. Corresponding to the measurement method, steps S11 - S14 relate to the calibration process, and steps S15 - S17 relate to the measurement process. However, since the measurement process needs to utilize the corresponding relationship obtained in step S14, steps S11 - S17 as a whole are the overall process of a measurement method.

[0076] In some embodiments, the space non-conservative force measurement system 100 responds to a calibration instruction, repeatedly executes steps S11 to S13 a predetermined number of times, and adjusts one or several of the acting point, acting direction, acting magnitude, and acting time of the standard force during each cycle, and executes step S14 after reaching the predetermined number of times. By repeatedly executing steps S11 to S13, measurement signals corresponding to different standard forces can be obtained. At the same time, based on the change situation of the standard force, combined with known information such as the mass and mass distribution of the force-bearing mechanism 120, the motion change situation of the force-bearing mechanism 120, such as acceleration response, is obtained through theoretical calculation. It should be noted that this theoretical calculation is a common theoretical calculation method in the art.

[0077] Figure 4 It is a schematic diagram of the calibration process in the space non-conservative force measurement method according to an embodiment of the present application. As Figure 4 shown, after obtaining the acceleration response from the force-bearing mechanism 120 and obtaining the output measurement signal from the motion state measurement mechanism 130, then combining the motion state change with the measurement signal to obtain the corresponding relationship between the motion state change and the measurement signal, thus completing the calibration of the space non-conservative force measurement system 100.

[0078] In some embodiments, the motion state change in step S12 includes the acceleration response of the force-bearing mechanism 120, and the motion state change is related to the characteristics of the standard force and the mass of the force-bearing mechanism 120. In some embodiments, the measurement signal in step S13 is related to the measurement range and resolution of the motion state measurement mechanism 130. In practical applications, the force-bearing mechanism 120 and the motion state measurement mechanism 130 should be matched with each other according to the measurement requirements.

[0079] During the calibration process, the acting point or acting area, magnitude, and direction of the standard force generated by the space standard force source 110 are adjustable. When the force-bearing mechanism 120 is subjected to this standard force, it can undergo motion state changes in six degrees of freedom in space, and the six degrees of freedom include three translational degrees of freedom and three rotational degrees of freedom. When an on-orbit flying spacecraft is subjected to space non-conservative forces, its motion state changes can be divided into two parts, translational and rotational, corresponding to the linear acceleration along the translational direction and the angular acceleration around one or more rotation axes respectively. To accurately measure the space non-conservative forces acting on the spacecraft, the system needs to be calibrated. The calibration can be performed before or after the measurement or during the measurement process.

[0080] In some embodiments, in step S11, the range of motion state change of the force receiving mechanism 120 under the action of a standard force is greater than the range of motion state change of the spacecraft when it is subjected to non-conservative forces. According to these embodiments, after performing the calibration process, the correspondence between the measurement signal of the motion state measurement mechanism 130 and the motion state change (acceleration response) of the force receiving mechanism 120 can be obtained within a sufficiently large measurement range of the spacecraft in six degrees of freedom. The purpose of such a setting is to make the calibration have a wider range of use. When the spacecraft is subjected to space non-conservative forces and generates an acceleration response within a certain range in any direction or around any axis, the acceleration information of the spacecraft can be obtained according to the measurement signal output by the motion state measurement mechanism and the obtained correspondence.

[0081] The following gives a specific calibration process:

[0082] Assume that the force receiving mechanism 120 is a space spacecraft, which is a rigid body, and its general motion can be decomposed into translation along the center of mass and rotation around the axis passing through the center of mass.

[0083] The force condition of the spacecraft at any time t is equivalent to (F, M, t) at the center of mass position, where F is the force on the spacecraft equivalent to the center of mass position, and M is the moment on the spacecraft equivalent to the center of mass position. Under the above center of mass force condition at this moment, the change in the flight state of the spacecraft can be expressed as (△a, △α, t), where a is the translational acceleration of the spacecraft and α is the rotational acceleration of the spacecraft.

[0084] At a determined time t 0 , a standard force (F 0 , M 0 , t 0 ) is applied to the spacecraft by using the space standard force source 110, which can simulate the force condition of the spacecraft during on-orbit flight. By recording the change in the spacecraft motion state (△a 0 , △α 0 , t 0 ), the correspondence between the standard force and the change in the spacecraft motion state is calibrated. Furthermore, during the subsequent measurement process, the non-conservative force information of the spacecraft can be obtained by observing the change in the spacecraft flight state.

[0085] In some embodiments, step S12 includes:

[0086] Step S121: The standard force is a single-direction force, the acting point of the standard force is on the surface of the force receiving mechanism, and the acting direction of the standard force is always perpendicular to the surface and outward;

[0087] Step S122: The force-bearing mechanism 120 has two opposite surfaces. A standard force is applied to the two opposite surfaces, generating two couples of forces parallel to the first axis. The two couples of forces generate a first moment about the second axis and a second moment about the third axis on the force-bearing mechanism, and cause a first angular acceleration change of the force-bearing mechanism 120 about the second axis and a second angular acceleration change about the third axis. The acceleration response of the force-bearing mechanism 120 includes the first angular acceleration change and the second angular acceleration change, wherein the first axis, the second axis, and the third axis are perpendicular to each other.

[0088] The following combines Figure 5A and Figure 5B to give the specific calibration process including steps S121 and S122:

[0089] Taking the spacecraft platform as the force-bearing mechanism 120, through the synthesis and decomposition of the space non-conservative forces acting on the spacecraft, it can be equivalently represented as a set of forces passing through the center of mass of the spacecraft and along the directions of three orthogonal coordinate axes in the space inertial coordinate system and moments about the three-axis directions. Among them, under the action of the forces along the three coordinate axes, the spacecraft generates linear accelerations along the corresponding directions; under the action of the moments about the three-axis directions, the spacecraft generates angular accelerations about the corresponding axes.

[0090] In some embodiments, as Figure 5A and Figure 5B shown, taking the spacecraft platform, that is, the force-bearing mechanism 120, as a cubic rigid body, that is, the cube in the figure, with the position of its center of mass O at the current moment as the coordinate origin, a three-dimensional space inertial coordinate system Oxyz is established. In this embodiment, it is assumed that the mass of the force-bearing mechanism 120 is m, and its moments of inertia about the three axes are I (I x , I y , I z ).

[0091] The space standard force source 110 can exert a tensile or compressive force on the force-bearing mechanism 120, which is determined by the specific force generation and application method. In this embodiment, it is assumed that the standard force provided by the space standard force source 110 is a unidirectional tensile force, the acting point is on the surface of the force-bearing mechanism 120, and its acting direction is always perpendicular to the surface of the force-bearing mechanism 120 and outward. Since it is a cubic rigid body, the force-bearing mechanism 120 has 3 pairs of opposite surfaces.

[0092] As Figure 5A shown, using the space standard force source 110, along the three axes passing through the center of mass, a standard force F (F x , F y , F z ) is applied to the force-bearing mechanism 120, then the linear acceleration change generated on the force-bearing mechanism is △a (F x / m, F y / m, Fz / m), where △a x = F x / m, △a y = F y / m, △a z = F z / m, as Figure 5B shown.

[0093] If an appropriate standard force is applied to the force-receiving mechanism 120, only a moment action can be generated on the force-receiving mechanism 120. This moment is M (M x , M y , M z ), causing the force-receiving mechanism 120 to have a change in angular acceleration △α (M x / I x , M y / I y , M z / I z ) about three axes of rotation, where △α x = M x / I x , △α y = M y / I y , △α z = M z / I z , as Figure 5B shown. M x is the moment about the x-axis generated by the standard force acting on the force-receiving mechanism 120, and I x is the moment of inertia of the force-receiving mechanism 120 about the x-axis direction. In this embodiment, the spatial standard force source 110 applies a standard force F (F Figure 5A ), parallel to the z-axis direction and not passing through the centroid of the force-receiving mechanism, as shown. F z1 , F z2 ). F z1 and F z2 are a pair of force couples, with the same magnitude, opposite directions, acting points on the upper and lower surfaces of the force-receiving mechanism respectively, and the acting points are symmetric with respect to the centroid. That is, in step S122, the two opposite surfaces are the upper surface and the lower surface. This force couple only generates a moment action on the force-receiving mechanism 120. Extend the line where the force F z1 is located in the opposite direction, and the intersection of this line with the xOy plane is point A. The distance between point A and the origin O of the coordinate system is d. The angle between the line segment OA and the x-axis of the coordinate system is θ. Then the moment about the x-axis generated by this force couple is M x = 2F z1 dsinθ. The moment about the y-axis generated by this force couple is M y = 2F z1dcosθ. Under the action of this couple, the change in angular acceleration of the force-bearing mechanism about the x-axis is Δα x = M x / I x , and the change in angular acceleration about the y-axis is Δα y = M y / I y . When θ = 0, the couple only generates a moment M y = 2F z1 d; when θ = 90°, the couple only generates a moment M x = 2F z1 d.

[0094] In other embodiments, the standard force can be applied to the front and rear surfaces of the cube shown in Figure 5A , generating moments about the x-axis and the z-axis on the force-bearing mechanism 120 and causing corresponding changes in the angular acceleration of the force-bearing mechanism 120. When the position of the couple application point is on the left and right surfaces of the cube, moments about the y-axis and the z-axis are generated on the force-bearing mechanism, and corresponding changes in the angular acceleration are generated.

[0095] In actual operation, according to the requirements of measurement or calibration tasks, a single or multiple forces can be applied to one or more surfaces of the force-bearing mechanism 120 to enable the force-bearing mechanism 120 to achieve changes in the motion state of six degrees of freedom.

[0096] In this calibration operation example, by applying a standard force with a known magnitude and direction to the force-bearing mechanism in the above manner, the force-bearing situation equivalent to that at its centroid position on the force-bearing mechanism is (F 0 , M 0 ). According to the mass and moment of inertia of the force-bearing mechanism, the acceleration response (a 0 , α 0 ) is calculated, and the measurement signal output by the motion state measurement mechanism is recorded. The magnitude, direction, or / and application point (or application area) of the standard force are changed multiple times, the change in the motion state of the force-bearing mechanism (acceleration response) is calculated, and the corresponding measurement signals output by the motion state measurement mechanism are respectively recorded. The corresponding relationship between the measurement signal output by the motion state measurement mechanism required for the task and the acceleration response of the force-bearing mechanism calculated is obtained, and the calibration of the measurement system is completed.

[0097] Figure 6 is a schematic diagram of the measurement process in the spatial non-conservative force measurement method according to an embodiment of the present application. As Figure 6As shown, for example, when the spacecraft is in orbit, non-conservative space forces act on the force-bearing mechanism 120. At this time, in step S15, the current measurement signal of the force-bearing mechanism 120 is measured and output by the motion state measurement mechanism 130. In step S16, based on the corresponding relationship obtained in the calibration process and the current measurement signal, the current change in the motion state of the force-bearing mechanism 120 can be obtained, such as the current acceleration response. And in step S17, based on this and the mass information of the force-bearing mechanism 120 and the current acceleration response, the non-conservative space forces acting on the spacecraft are calculated using the laws of kinematics, that is, the measured value of the non-conservative space forces is obtained, realizing the measurement of non-conservative space forces. The calculation process of calculating the non-conservative space forces using the laws of kinematics can be a conventional process in the art.

[0098] In some embodiments, according to different settings of the force-bearing structure 120, step S15 includes:

[0099] Step S151: When the force-bearing mechanism 120 is subjected to non-conservative space forces, the motion state measurement mechanism 130 measures the current measurement signal of the force-bearing mechanism 110; this step is applicable to the case where the force-bearing mechanism 120 is set as the spacecraft platform or a part of the spacecraft platform.

[0100] Step S152: When the force-bearing mechanism 120 is not subjected to non-conservative space forces, the spacecraft platform is subjected to non-conservative space forces, and a relative motion change occurs between the force-bearing mechanism 120 and the spacecraft platform. The motion state measurement mechanism 130 measures the current measurement signal corresponding to the relative motion change. This step is applicable to the force-bearing mechanism 120 being Figure 2 a part of the carried component shown in the figure, and the carried component is in an inertial flight state.

[0101] The non-conservative space force measurement system and measurement method of the present application at least include the following beneficial effects:

[0102] (1) It can realize real-time on-orbit calibration of the non-conservative space force measurement system. One of the key components of this system is the space standard force source 110, which enables the system to have the ability of on-orbit real-time calibration. The calibrated measurement system can achieve accurate measurement of non-conservative space forces.

[0103] (2) The action of space non-conservative forces on an orbiting spacecraft may cause it to undergo translational and / or rotational motions. To achieve precise measurement of space non-conservative forces that are multi-source and time-varying, when the standard force generated by the space standard force source 110 acts on the force-receiving mechanism 120, it should be able to cause corresponding changes in the motion state as when it is under the action of space non-conservative forces, such as the direction and magnitude of acceleration. By using the space standard force source 110 in this system, a standard force with different action points (or different regions), different action directions, and adjustable magnitudes can be applied to the force-receiving mechanism 120. Under the action of this standard force, the force-receiving mechanism 120 can undergo changes in the motion state in six degrees of freedom in space (three translational degrees of freedom and three rotational degrees of freedom).

[0104] (3) This measurement system can select different space standard force sources 110, force-receiving mechanisms 120, and motion state measurement methods according to mission requirements. Therefore, it has a wide range of measured space non-conservative force values and extensive application scenarios.

[0105] (4) By selecting the motion state measurement mechanism 130, for example, using a device based on optical, electrical, or electromagnetic measurement methods, the system can have high measurement accuracy and real-time measurement capabilities.

[0106] (5) This system has the ability to perform in-orbit real-time calibration. After calibration, the system can directly and precisely measure the non-conservative forces in the space environment without the need for post-processing of the measurement data. Its measurement has the characteristic of high real-time performance, which is beneficial for realizing real-time control of the attitude and orbit of the spacecraft.

[0107] The basic concepts have been described above. Obviously, for those skilled in the art, the above application disclosure is only an example and does not constitute a limitation to this application. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are proposed in this application, so such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.

[0108] At the same time, this application uses specific terms to describe the embodiments of this application. Such as "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification is not necessarily the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0109] Similarly, it should be noted that, in order to simplify the description disclosed in this application and thus help the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of this application, sometimes multiple features are merged into one embodiment, drawing or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than those mentioned in the claims. In fact, the features of the embodiments are fewer than all the features of the single embodiment disclosed above.

[0110] In some embodiments, numbers are used to describe components and the quantity of attributes. It should be understood that such numbers used for the description of embodiments are modified by the modifiers "about", "approximate" or "substantially" in some examples. Unless otherwise stated, "about", "approximate" or "substantially" indicate that the said numbers allow a variation of ±20%. Accordingly, in some embodiments, the numerical parameters used in this application are all approximate values, and such approximate values may change according to the characteristics required by individual embodiments. In some embodiments, the numerical parameters should consider the specified significant digits and adopt the method of retaining the general number of digits. Although the numerical ranges and parameters used in some embodiments of this application to confirm the breadth of their scope are approximate values, in specific embodiments, the setting of such numerical values is as precise as possible within the feasible range.

Claims

1. A space non-conservative force measurement system for spacecraft in orbit, It is characterized in that include: A space standard force source, used to generate a standard force in a space environment and apply the standard force to a force-bearing mechanism, wherein the direction and magnitude of the standard force are known; A force-bearing mechanism, used to receive the standard force and produce a change in motion state, wherein the mass and mass distribution of the force-bearing mechanism are known; A motion state measuring mechanism, used to measure the motion state change of the force-bearing mechanism under the action of the standard force or the non-conservative force in the external space, and output a measurement signal; The controller is configured as: Obtaining the change in the motion state of the force-bearing mechanism under the action of the standard force through theoretical calculation, establishing a corresponding relationship between the change in the motion state and the measurement signal, and, When measuring space non-conservative forces, the current measurement signal of the force-bearing mechanism is measured by a motion state measurement mechanism, and the current motion state change is obtained based on the corresponding relationship and the current measurement signal. The space non-conservative forces acting on the spacecraft are calculated using the laws of kinematics based on the current motion state change and the mass information of the force-bearing mechanism.

2. The spatial non-conservative force measurement system according to claim 1, It is characterized in that The motion state change includes the acceleration response of the force-bearing mechanism.

3. The spatial non-conservative force measurement system according to claim 1, It is characterized in that The force-bearing structure includes a spacecraft platform, and / or a part of a spacecraft platform.

4. The spatial non-conservative force measurement system according to claim 1, It is characterized in that The force-bearing mechanism includes a carrying component inside the spacecraft, and / or a part of the carrying component. The carrying component is in a flight state in the spacecraft without being affected by non-conservative forces in the external space, and the motion state measuring mechanism is arranged on the spacecraft platform.

5. The spatial non-conservative force measurement system according to claim 4, It is characterized in that The carrying component is in an inertial flight state.

6. The spatial non-conservative force measurement system according to claim 4, It is characterized in that The spacecraft platform generates a force on the carrying component through any of the following methods: magnetic suspension, electrostatic suspension, wire suspension, and low-rigidity elastic connection.

7. The spatial non-conservative force measurement system according to claim 1, It is characterized in that The motion state measurement mechanism includes a satellite-borne accelerometer, and the measurement signal includes acceleration changes.

8. The spatial non-conservative force measurement system according to claim 1, It is characterized in that The motion state measuring mechanism includes a gyroscope, a star sensor or a sun sensor, and the measurement signal includes a rotation acceleration change or a pointing angle change.

9. The spatial non-conservative force measurement system according to claim 1, It is characterized in that The motion state measurement mechanism includes an inter-satellite or satellite-to-ground ranging system, and the measurement signal includes a position change of the spacecraft.

10. The spatial non-conservative force measurement system according to claim 1, It is characterized in that The motion state measurement mechanism includes a relative quantity measurement device based on the principle of electrostatics, electromagnetics or laser interference, and the measurement signal includes the relative distance and relative angle change between the force-bearing mechanism and the spacecraft or the carried component.

11. The spatial non-conservative force measurement system according to claim 1, It is characterized in that The motion state measurement mechanism includes a Doppler measurement device based on the Doppler effect, and the measurement signal includes a relative speed change of the spacecraft.

12. A method for measuring non-conservative forces in space during on-orbit flight of a spacecraft. It is characterized in that include: Step S11: generating a standard force from a spatial standard force source, and applying the standard force to a force-bearing mechanism; Step S12: obtaining the change of the motion state of the force-bearing mechanism under the action of the standard force through theoretical calculation; Step S13: measuring a measurement signal of the force-bearing mechanism by a motion state measuring mechanism; Step S14: establishing a corresponding relationship between the motion state change and the measurement signal; Step S15: when measuring the spatial non-conservative force, measuring the current measurement signal of the force-bearing mechanism by the motion state measurement mechanism; Step S16: obtaining a current motion state change according to the corresponding relationship and the current measurement signal; Step S17: Based on the current motion state change and the mass information of the force-bearing structure, the spatial non-conservative force acting on the spacecraft is calculated using the kinematics law.

13. The spatial non-conservative force measurement method according to claim 12, It is characterized in that Also includes: In response to the calibration instruction, steps S11 to S13 are repeated for a predetermined number of times, and one or more of the point of action, direction of action, magnitude of action and action time of the standard force are adjusted in each cycle, and step S14 is executed after reaching the predetermined number of times.

14. The spatial non-conservative force measurement method according to claim 13, It is characterized in that In the step S11, the range of motion state change of the force-bearing mechanism under the action of the standard force is greater than the range of motion state change of the spacecraft when it is acted upon by a non-conservative force.

15. The spatial non-conservative force measurement method according to claim 12, It is characterized in that Step S11 includes: applying one or more standard forces to one surface or multiple surfaces of the force-bearing mechanism, so that the force-bearing mechanism produces a six-degree-of-freedom motion state change.

16. The spatial non-conservative force measurement method according to claim 12, It is characterized in that Step S12 includes: The standard force is a unidirectional force, the point of action of the standard force is on the surface of the force-bearing mechanism, and the direction of action of the standard force is always perpendicular to the surface and outward; The force-bearing mechanism has two opposite surfaces, and the standard force is applied to the two opposite surfaces to generate two couples parallel to the first axis. The two couples generate a first torque around the second axis and a second torque around the third axis on the force-bearing mechanism, and cause the force-bearing mechanism to generate a first angular acceleration change around the second axis and a second angular acceleration change around the third axis. The acceleration response of the force-bearing mechanism includes the first angular acceleration change and the second angular acceleration change, wherein the first axis, the second axis and the third axis are perpendicular to each other.

17. The spatial non-conservative force measurement method according to claim 12, It is characterized in that In the step S12, the motion state change includes the acceleration response of the force-bearing mechanism, and the motion state change is related to the characteristics of the standard force and the mass of the force-bearing mechanism.

18. The spatial non-conservative force measurement method according to claim 12, It is characterized in that In the step S13, the measurement signal is related to the measurement range and resolution of the motion state measurement mechanism.

19. The spatial non-conservative force measurement method according to claim 12, It is characterized in that Also includes: In response to the measurement instruction, steps S15 to S17 are executed.

20. The spatial non-conservative force measurement method according to claim 12, It is characterized in that The step S15 comprises: Step S151: when the force-bearing mechanism is subjected to the spatial non-conservative force, the motion state measuring mechanism measures a current measurement signal of the force-bearing mechanism; Step S152: When the force-bearing mechanism is not subjected to the spatial non-conservative force, the spacecraft platform is subjected to the spatial non-conservative force, the force-bearing mechanism and the spacecraft platform undergo a relative motion change, and the motion state measurement mechanism measures a current measurement signal corresponding to the relative motion change.

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