A method and system for detecting a thrust drop in a transfer orbit electric propulsion satellite

Abstract

The application discloses a transfer orbit electric propulsion satellite thrust drop detection method and system, comprising: establishing a single electric thruster real-time thrust-force variation relation model according to satellite data; calculating a satellite force tolerance range according to the single electric thruster real-time thrust-force variation relation model based on the single electric thruster real-time thrust-force variation relation model; if the electric thruster has a fault, determining the installation position of the faulty electric thruster first; according to the force size at different time within the satellite working time range and the installation position of the faulty electric thruster, determining the fault mode of the faulty electric thruster by using the fault mode function of the faulty electric thruster, and generating a faulty thruster thrust curve. The application can effectively track any form of thrust variation, lock the faulty thruster and determine the fault mode, so that timely correction measures are taken to ensure that the orbit and attitude of the satellite are kept in the predetermined target range.

Description

A method and system for detecting thrust decrease in transfer orbit electric propulsion satellites Technical Field

[0001] This invention relates to the field of satellite thrust reduction detection technology, and specifically to a method and system for detecting thrust reduction in a transfer orbit electric propulsion satellite. Background Technology

[0002] In satellite missions, satellites need to be transferred from their post-launch orbit to their final mission orbit. An electric propulsion transfer orbit is an intermediate orbit used to achieve this process. During this process, the satellite uses its electric propulsion system to change its orbit so that it can perform its intended mission, such as communication, Earth observation, or scientific research, in its final mission orbit.

[0003] With the continuous development of satellite technology, electric propulsion systems have become one of the main propulsion methods in modern space missions. Electric propulsion systems offer excellent efficiency and precise control capabilities, enabling satellites to perform various tasks in space, including orbit transfer, stable attitude control, and precise orbit maintenance. Electric propulsion systems typically provide longer propulsion durations, making them particularly suitable for orbit transfers, which are often time-consuming. However, electric propulsion systems also face various potential faults and problems, one of which is thrust reduction. When the thrust of an electric thruster decreases, the satellite's orbit and attitude will be irreversibly affected, potentially leading to mission failure or reduced satellite lifespan. Therefore, it is necessary to study thruster fault detection and corrective measures such as position maintenance. This includes two parts: first, detecting the thruster's fault state and tracking changes in thrust output; second, shutting down the faulty thruster and eliminating orbital drift caused by the thruster fault. Current literature only studies position maintenance strategies in complete mode or only for position maintenance strategies where the fault state is known. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for detecting thrust reduction in transfer orbit electric propulsion satellites, which can effectively track any form of thrust change, locate faulty thrusters and determine the fault mode, thereby taking timely corrective measures to ensure that the satellite's orbit and attitude remain within the predetermined target range.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] This invention provides a method for detecting thrust reduction in a transfer orbit electric propulsion satellite, comprising:

[0007] S1: Acquire satellite data;

[0008] S2: Based on the satellite data, establish a real-time thrust-resultant force variation model for a single electric thruster;

[0009] S3: Based on the real-time thrust-resultant force variation model of a single electric thruster, calculate the satellite resultant force tolerance range according to the thrust tolerance range of the electric thruster;

[0010] S4: Determine whether the actual net force on the satellite is within the satellite's net force tolerance range. If so, there is no fault; otherwise, proceed to S5.

[0011] S5: Based on the actual resultant force acting on the satellite, the installation location of the faulty electric thruster is determined using the real-time thrust-resultant force variation model of the single electric thruster.

[0012] S6: Based on the resultant force value at different times within the satellite's operating time range and the installation location of the faulty electric thruster, the fault mode of the faulty electric thruster is determined using the fault mode function of the faulty electric thruster, and the thrust curve of the faulty thruster is generated.

[0013] Alternatively, in step S1, the satellite data includes:

[0014] Input the satellite's real-time centroid position, the actual installation position of the electric thruster, the rated thrust of the electric thruster, the thrust tolerance range of the electric thruster, the fault mode function data, and the real-time data;

[0015] The real-time data includes the satellite's real-time center of mass position and the actual resultant force data acting on the satellite.

[0016] Alternatively, S2 may include:

[0017] S21: Using the real-time position of the satellite's center of mass as a reference point, with the origin o of the coordinate system as the satellite's center of mass, and X, Y, and Z pointing to the satellite's characteristic axes respectively. Based on the actual installation position of the electric thruster, determine the relative installation position of the electric thruster in the transfer orbit;

[0018] S22: Based on the relative installation position of the electric thruster under the transfer track, establish the thrust model of the electric thruster under the transfer track;

[0019] S23: Based on the electric thruster thrust model under the transfer trajectory, and based on the calculation rules of resultant force and resultant torque, establish a single electric thruster thrust-resultant force calculation relationship model under the transfer trajectory;

[0020] S24: Based on the single electric thruster thrust-resultant force calculation relationship model under the transfer trajectory, calculate the magnitude and direction of the resultant force vector;

[0021] S25: Control the working state of the single electric thruster from 0-100%. Based on the thrust-resultant force calculation relationship model of the single electric thruster, the magnitude and direction of the resultant force vector, establish the thrust-resultant force change relationship model of the single electric thruster.

[0022] Alternatively, in step S21, the actual installation location of the electric thruster is determined by the thruster layout scheme and the thruster configuration scheme.

[0023] The thruster layout scheme is as follows:

[0024] Four electric thrusters are mounted on the satellite's back floor via a vector adjustment mechanism, with the thrust direction perpendicular to the back floor. The four electric thrusters are arranged in a rectangular pattern on the back floor.

[0025] The thruster configuration scheme is as follows:

[0026] Four thrusters are symmetrically installed on the ground behind the satellite, two on the south side and two on the north side;

[0027] In S23, the calculation model for the thrust-resultant force of the electric thruster under the transfer orbit is as follows:

[0028] F 合 =F1+F2+F3+F4

[0029] Among them, F1-F4 represent the thrust of each of the four thrusters, F 合 For the sake of combined efforts.

[0030] The resultant force direction calculation takes into account the influence of torque, and it is the result of the normalization of the superimposed torque of the four thrust directions.

[0031] In S24, the direction of the resultant force vector is represented by the elevation angle theta and the deflection angle alpha of the resultant force direction;

[0032] The relationship between theta, alpha and x, y, z is as follows:

[0033]

[0034] Where x, y, and z are referred to as the lateral, longitudinal, and vertical installation positions of the electric thruster, respectively; theta is the angle between the thrust direction and the Y-axis, and alpha is the angle between the projection of the thrust direction onto the XOZ plane and the Z-axis.

[0035] Alternatively, S3 includes:

[0036] S31: Based on the thrust tolerance range of the thrusters, and using the Monte Carlo method, simulate 10,000 times to randomly generate thrust within the tolerance range of all thrusters, forming a thrust matrix;

[0037] S33: Calculate the magnitude and direction of the resultant force based on the thrust matrix and the thrust-resultant force calculation relationship model of a single electric thruster;

[0038] S34: Based on the magnitude and direction of the resultant force from 10,000 Monte Carlo simulations, calculate the tolerance range of the resultant force of the electric thruster when the fault is within tolerance.

[0039] Optionally, in step S4, a fault model is used to determine whether the actual net force acting on the satellite is within the satellite's net force tolerance range. The fault model is:

[0040]

[0041] Among them, F percent The value represents the degree of failure of the faulty thruster, ranging from 0 to 100. A value of 100 indicates that the thruster is not faulty. percent / 100 represents the current thrust as a percentage of the fault-free condition, and t is the current operating time. rand The intermediate operating time of the randomly generated electric thruster is used to simulate the thrust variation of a faulty thruster.

[0042] Alternatively, S6 includes:

[0043] S61: Determine the faulty electric thruster based on its installation location;

[0044] S62: Obtain the magnitude of the resultant force at different times within the satellite's operating time range;

[0045] S63: Based on the magnitude of the resultant force at different times within the satellite's operating time range, the failure mode of the faulty electric thruster is determined using the failure mode function;

[0046] S64: Generate the thrust curve of the faulty electric thruster based on the fault mode of the faulty electric thruster.

[0047] Optionally, the faulty electric thruster includes four fault modes, wherein the thrust of the thruster varies with the operating time t, which is between 0 and 100 s:

[0048] Failure mode 1: The thruster's operating status abruptly changes from 100% to 0;

[0049] Failure Mode 2: The thruster's operating status gradually changes from 100% to 0%;

[0050] Failure Mode 3: The thruster's operating status changes from 100% to x% and then remains unchanged;

[0051] Failure Mode 4: The thruster's operating status changes from 100% to x%, and then from x% back to 100%.

[0052] Alternatively, the fault mode function includes:

[0053]

[0054] Wherein, 1, 2, 3, and 4 represent four different fault modes, and 1 represents the thrust suddenly becoming 0; 2 represents the thrust gradually becoming 0; 3 represents the thrust gradually becoming x% and then remaining unchanged; 4 represents the thrust gradually becoming x% and then returning to 100%. totalforce(end) represents the final value of the resultant force during the working time of the electric thruster, totalforce represents the rated resultant force under fault-free conditions, totalforce(1) represents the resultant force at the initial moment within the working time range, and totalforce(500) represents the resultant force at the middle moment within the working time range.

[0055] The present invention also provides a system based on the above-described method for detecting thrust decrease in electric propulsion satellites in transfer orbit, the system comprising:

[0056] Data acquisition module, the data acquisition module is used to acquire satellite data;

[0057] The model building module establishes a real-time thrust-resultant force variation model for a single electric thruster based on the satellite data.

[0058] The resultant force tolerance range calculation module is used to calculate the satellite resultant force tolerance range based on the real-time thrust-resultant force change relationship model of a single electric thruster and the thrust tolerance range of the electric thruster.

[0059] The fault judgment module is used to determine whether the actual resultant force on the satellite is within the tolerance range of the satellite thrust resultant force.

[0060] The fault location determination module is used to determine the installation location of the faulty electric thruster based on the actual resultant force acting on the satellite and using the real-time thrust-resultant force variation relationship model of the single electric thruster.

[0061] The curve generation module is used to determine the failure mode of the faulty electric thruster and generate the thrust curve of the faulty thruster by using the failure mode function of the faulty electric thruster, based on the resultant force value at different times within the satellite's working time range and the installation location of the faulty electric thruster.

[0062] The present invention has the following beneficial effects:

[0063] 1. This invention only requires acquiring the resultant force data during satellite orbit transfer to locate the faulty thruster and detect the thrust failure mode. The required data acquisition is simple, the data volume is small, and the computational load is low, simplifying the model and improving computational efficiency. It facilitates real-time detection of thruster thrust reduction and is suitable for practical engineering applications.

[0064] 2. This invention has strong scalability. Without the need to design auxiliary variables, it can deduce the fault mode after knowing the change in the resultant force, and can accurately estimate the thrust under the fault mode. Furthermore, by reasonably selecting the parameters of the fault mode, the types and number of fault modes can be increased, that is, it can effectively track the thrust change of any fault thruster under any fault mode, thereby effectively dealing with thrust failures during satellite orbit change operations.

[0065] 3. This invention is highly portable and can be integrated into a graphical interface without any limitations. It can be applied in any actual track-changing scenario. Attached Figure Description

[0066] Figure 1 is a schematic diagram of the resultant thrust relationship of the four thrusters under the transfer trajectory;

[0067] Figure 2 is a flowchart of the thrust reduction detection method for electric propulsion satellites in transfer orbit;

[0068] Figure 3 is a schematic diagram of the installation location coordinates;

[0069] Figure 4 is a vector diagram showing the relationship between the thrust and the resultant force of thruster 1;

[0070] Figure 5 is a vector diagram showing the relationship between the thrust and the resultant force of thruster 2;

[0071] Figure 6 is a vector diagram showing the relationship between the thrust and resultant force of thruster 3;

[0072] Figure 7 is a vector diagram showing the relationship between the thrust and resultant force of thruster 4;

[0073] Figure 8 shows the relationship between the thrust and the direction of the resultant force of the thruster.

[0074] Figure 9 is a schematic diagram of the resultant force tolerance range of thruster 1;

[0075] Figure 10 is a schematic diagram of the test results when thruster 1 is fault-free;

[0076] Figure 11 is a schematic diagram of the detection results when thruster 1 is in fault mode 1;

[0077] Figure 12 is a schematic diagram of the detection results when thruster 1 is in fault mode 2;

[0078] Figure 13 is a schematic diagram of the detection results when thruster 1 is in fault mode 3. Detailed Implementation

[0079] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0080] This invention provides a thrust reduction detection system for electric propulsion satellites in transfer orbit, comprising:

[0081] The data acquisition module is used to acquire satellite data, which specifically includes the thruster installation location, satellite center of mass location, thruster layout scheme, initial thruster size, and electric thrust tolerance range.

[0082] Those skilled in the art can configure the thruster installation location, satellite center of mass location, thruster layout scheme, and initial thruster size to enable the data acquisition module of this invention to obtain satellite data.

[0083] As one implementation method, the thruster layout can be a rectangular layout, specifically:

[0084] The rectangular configuration is a common arrangement for electric thrusters on GEO satellites. This configuration involves four electric thrusters mounted on the satellite's backplane via a vector control mechanism, arranged in a rectangular shape. The advantages of this configuration are that it simultaneously ensures position control and angular momentum unloading capabilities in the east-west and north-south directions, while also allowing the thrusters to pass through the center of mass. It avoids the impact of thruster plumes on other components such as the solar panels. Furthermore, it maintains position control and unloading capabilities even in the event of a failure of one or two thrusters. Therefore, among satellites equipped with four electric thrusters for position control and angular momentum unloading, the rectangular configuration offers the highest redundancy.

[0085] Based on this, the thruster configuration scheme can be determined:

[0086] Four thrusters are symmetrically mounted on the ground behind the satellite, two on the south side and two on the north side. The direction of the thrusters is adjusted in real time by a thrust vectoring control mechanism. The thrust vectoring control device is an important component of the four-thrust configuration. The thrusters are mounted on the thrust vectoring device, and their installation angle is not fixed but can be adjusted as needed to ensure flexible and efficient execution of different space missions. Compared to the fixed installation configuration of thrusters, the thrust vectoring control mechanism offers high flexibility, strong environmental adaptability, large load-bearing capacity, and long service life.

[0087] Assume the satellite has a cube-shaped structure with sides of 2m × 2m × 2m. oxyz is the satellite's coordinate system, and the northeast direction refers to the northeast direction of the Earth.

[0088] As one implementation method, the thruster installation position can be described by two sets of parameters: the coordinates (x, y, z) of the thrust application point of the electric thruster in the satellite's centroid coordinate system; and the elevation angle theta (θ) and deflection angle alpha (α) of the thrust direction of the electric thruster. Here, x, y, and z are respectively referred to as the lateral, longitudinal, and vertical installation positions of the electric thruster; theta is the angle between the thrust direction and the Y-axis, and alpha is the angle between the projection of the thrust direction onto the XOZ plane and the Z-axis. The relationship between theta, alpha, and x, y, and z is as follows:

[0089]

[0090] The satellite's center of mass position can be obtained based on the selected coordinate system. If the satellite's center of mass position is used as a reference point, its coordinates are (0,0). The initial thrust magnitude can be set according to the actual situation. As a specific implementation, this invention considers an initial thrust of 200mN, with the thruster operating at 100% capacity under normal conditions.

[0091] Based on the above technical solution, the model building module of the present invention is used to establish a satellite thrust-resultant force variation relationship model based on satellite data.

[0092] Optionally, a thrust model of the thruster under the transfer trajectory can be established based on the thruster installation location;

[0093] During the orbit change phase, the four thrusters installed on the satellite's back surface ignite and operate. During the orbit change, the thrust vector adjustment mechanism adjusts the thrust vector to be perpendicular to the back surface. Under the satellite's orbit transfer control strategy, the obtained control force vector is used for orbit transfer. Therefore, the thrust direction of all four thrusters is perpendicular to the back surface.

[0094] Based on the thrust model of the thruster under the transfer trajectory, a calculation relationship model for the resultant thrust of the thruster under the transfer trajectory is established, as shown in Figure 1:

[0095] Resultant force magnitude: Since the thrust vector of the thruster is always perpendicular to the back of the floor, the resultant force is simply the sum of the thrust magnitudes. That is, F. 合 =F1+F2+F3+F4

[0096] Resultant force direction: Considering the effect of torque, which is generated by each thruster, it represents the rotational effect of a force vector relative to a reference point. Torque does not directly change the magnitude of the resultant force, but rather determines its direction to keep the system in equilibrium. It represents the rotational effect of a force vector relative to a reference point. In other words, the direction of the resultant force is the normalized result of the sum of the directions of the four thrusts and their corresponding torques.

[0097] The resultant force tolerance range calculation module is used to calculate the tolerance range of the satellite resultant force when the satellite thruster failure is within the tolerance range by conducting 10,000 Monte Carlo experiments based on the satellite thrust-resultant force variation relationship model.

[0098] After obtaining the resultant force tolerance range, the present invention uses a fault judgment module to determine whether the satellite resultant force is within the resultant force tolerance range.

[0099] It should be noted that the present invention sets the thrust preset range of a single thruster to be the normal working state under 100% conditions, but it is within the normal tolerance range between 95% and 105%.

[0100] The fault generation module is used to randomly generate thruster faults using a fault generation function.

[0101] Furthermore, there are four modes of thruster failure, with the thrust changing with time t, which is between 0 and 100 seconds. The first failure mode is a sudden change from 1 to 0; the second is a gradual change from 100% to 0; the third is a change from 100% to x% and then remaining constant; and the fourth is a change from 100% to x% and then back to 100%. Therefore, this invention labels the different failure modes as 1, 2, 3, and 4, and plans to randomly set these failures in the program. Each experiment generates a random number; the specific number generated will indicate the failure in that experiment. The magnitude and direction of the resultant force are then calculated based on these failures. This invention determines failures through a failure model, which is as follows:

[0102]

[0103] The curve generation module is used to determine the thruster failure status based on the satellite thrust-resultant force variation model, so as to generate the thrust curve of the failed thruster.

[0104] The present invention also provides a method for detecting thrust decrease in a transfer orbit electric propulsion satellite, as shown in Figure 2, comprising:

[0105] S1: Acquire satellite data;

[0106] Input the satellite's real-time centroid position, the actual installation position of the electric thruster, the rated thrust of the electric thruster, the thrust tolerance range of the electric thruster, the fault mode function data, and the real-time data;

[0107] Real-time data includes the satellite's real-time center of mass position and the actual resultant force acting on the satellite.

[0108] S2: Based on the satellite data, establish a real-time thrust-resultant force variation model for a single electric thruster;

[0109] Alternatively, S2 may include:

[0110] S21: Using the real-time centroid position of the satellite as a reference point, determine the relative installation position of the electric thruster under the transfer orbit based on the actual installation position of the electric thruster;

[0111] The actual installation location of the electric thruster is determined by the thruster layout scheme and the thruster configuration scheme;

[0112] The thruster layout is as follows: four electric thrusters are installed on the satellite's back floor via a vector adjustment mechanism, with the thrust direction passing through the center of mass. The four electric thrusters are arranged in a rectangular pattern on the back floor.

[0113] The thruster configuration is as follows: four thrusters are symmetrically installed on the ground behind the satellite, two on the south side and two on the north side.

[0114] S22: Based on the relative installation position of the electric thruster under the transfer track, establish the thrust model of the electric thruster under the transfer track;

[0115] S23: Based on the electric thruster thrust model under the transfer trajectory, and based on the calculation rules of resultant force and resultant torque, establish a single electric thruster thrust-resultant force calculation relationship model under the transfer trajectory;

[0116] The thrust-resultant force calculation model for a single electric thruster under transfer orbit is as follows:

[0117] F 合 =F1+F2+F3+F4

[0118] Among them, F1-F4 represent the thrust of each of the four thrusters, F 合 For the sake of combined efforts.

[0119] S24: Based on the single electric thruster thrust-resultant force calculation relationship model under the transfer trajectory, calculate the magnitude and direction of the resultant force vector;

[0120] The direction of the resultant force vector is represented by the elevation angle theta and the deflection angle alpha of the resultant force direction;

[0121] The relationship between theta, alpha and x, y, z is as follows:

[0122]

[0123] Where x, y, and z are referred to as the lateral, longitudinal, and vertical installation positions of the electric thruster, respectively; theta is the angle between the thrust direction and the Y-axis, and alpha is the angle between the projection of the thrust direction onto the XOZ plane and the Z-axis.

[0124] Resultant force direction: Considering the influence of torque, which is generated by each thruster, the direction of the resultant force is the normalized result of the sum of the torques of the four thrust directions.

[0125] S25: Control the working state of the single electric thruster from 0-100%. Based on the thrust-resultant force calculation relationship model of the single electric thruster, the magnitude and direction of the resultant force vector, establish the thrust-resultant force change relationship model of the single electric thruster.

[0126] S3: Based on the real-time thrust-resultant force variation model of a single electric thruster, calculate the satellite resultant force tolerance range according to the thrust tolerance range of the electric thruster;

[0127] Alternatively, S3 includes:

[0128] S31: Based on the satellite thrust-resultant force variation model, determine the tolerance range of the thruster thrust;

[0129] The present invention sets the thrust preset range of a single thruster to be the normal working state under 100% conditions, but it is within the normal tolerance range between 95% and 105%.

[0130] S31: Based on the thrust tolerance range of the thrusters, and using the Monte Carlo method, simulate 10,000 times to randomly generate thrust within the tolerance range of all thrusters, forming a thrust matrix;

[0131] S33: Calculate the magnitude and direction of the resultant force based on the thrust matrix and the thrust-resultant force calculation relationship model of a single electric thruster;

[0132] S34: Based on the magnitude and direction of the resultant force from 10,000 Monte Carlo simulations, calculate the tolerance range of the resultant force of the electric thruster when the fault is within the tolerance range.

[0133] Specifically, 10,000 Monte Carlo simulations were performed. During each simulation, a number between 0.95 and 1.05 was randomly generated. These random numbers formed a 1x4 thrust matrix, which was multiplied by the normal resultant force magnitude of 200N to obtain the four-thrust matrix for that simulation. This random number was then recorded in a 100x4 matrix. The magnitude and direction of the resultant force were calculated using the thrust matrix. Here, cosalpha = z / |F| represents the coordinate value of the vertical installation position, and F represents the direction of the resultant force.

[0134] S4: Determine whether the actual net force on the satellite is within the tolerance range of the satellite thrust net force. If so, there is no fault; otherwise, proceed to S5.

[0135] This invention uses a fault model to determine whether the actual resultant force acting on the satellite is within the tolerance range of the satellite's thrust resultant force. The fault model is as follows:

[0136]

[0137] Among them, F percent The value represents the degree of failure of the faulty thruster, ranging from 0 to 100. A value of 100 indicates that the thruster is not faulty. percent / 100 represents the current thrust as a percentage of the fault-free condition, and t is the current operating time. randThe intermediate operating time of the randomly generated electric thruster is used to simulate the thrust variation of a faulty thruster.

[0138] S5: Based on the actual resultant force acting on the satellite, the installation location of the faulty electric thruster is determined using the real-time thrust-resultant force variation model of the single electric thruster.

[0139] S6: Based on the resultant force value at different times within the satellite's operating time range and the installation location of the faulty electric thruster, the fault mode of the faulty electric thruster is determined using the fault mode function of the faulty electric thruster, and the thrust curve of the faulty thruster is generated.

[0140] Alternatively, S6 includes:

[0141] S61: Determine the faulty electric thruster based on its installation location;

[0142] If we consider the installation location as shown in Figure 3, the initial thrust is 200N, and the thruster is normally at 100%.

[0143] According to the model of the relationship between the thrust and the resultant force of the satellite thruster during orbit transfer, if the cosalpha angle is between 0.0295 and 0.6245, and the cosheta angle is between -0.7471 and 0.4015, then it is a thruster failure.

[0144] If the cosalpha angle is between 0.0295 and 0.6245, and the cosheta angle is between 0.6297 and 0.7637, then the thruster is faulty.

[0145] If the cosalpha angle is between 0.0313 and 0.8002, and the cosheta angle is between -0.7692 and 0.4898, then it is a third thruster fault.

[0146] If the cosalpha angle is between 0.0313 and 0.8002, and the cosheta angle is between 0.7204 and 0.9280, then it is a thruster malfunction.

[0147] S62: Obtain the resultant force value at different times within the satellite's operating time range;

[0148] S63: Based on the resultant force value at different times within the satellite's operating time range, the failure mode of the faulty electric thruster is determined using the failure mode function;

[0149] After identifying which thruster is malfunctioning, the type of malfunction is determined by the pattern of change in the resultant force. If the resultant force abruptly drops to 0, it's the first type of malfunction. If the resultant force gradually decreases to 0, it's the second type of malfunction. If the resultant force gradually decreases to x% and then remains constant, it's the third type of malfunction. If the resultant force gradually decreases to x% and then returns to 100%, it's the fourth type of malfunction.

[0150] The specific logic for diagnosing the fault is as follows:

[0151]

[0152] Wherein, 1, 2, 3, and 4 represent four different fault modes, and 1 represents the thrust suddenly becoming 0; 2 represents the thrust gradually becoming 0; 3 represents the thrust gradually becoming x% and then remaining unchanged; 4 represents the thrust gradually becoming x% and then returning to 100%. totalforce(end) represents the final value of the resultant force during the working time of the electric thruster, totalforce represents the rated resultant force under fault-free conditions, totalforce(1) represents the resultant force at the initial moment within the working time range, and totalforce(500) represents the resultant force at the middle moment within the working time range.

[0153] S64: Generate the thrust curve of the faulty electric thruster based on the fault mode of the faulty electric thruster.

[0154] After determining which thruster experienced which type of failure, the thrust magnitude change of that thruster is calculated based on the failure mode, and a graph of the calculated thrust magnitude change of that thruster is drawn and compared with the actual thrust magnitude change graph.

[0155] The thrust magnitude can be estimated based on the failure mode. Given the failure mode, if it's the first type of failure, the thrust abruptly drops to 0. If it's the second type of failure, the thrust gradually decreases to 0; if it's the third type of failure, the thrust gradually decreases to x% and then remains constant; if it's the fourth type of failure, the thrust gradually decreases to x% and then returns to 100%. Finally, a diagram showing the estimated thrust changes due to failures is drawn.

[0156] With a rated thrust of 200N, thruster installation positions of [[-118.9, -100, -1300]; [118.9, -100, -1300]; [-118.9, 100, -1300]; [118.9, 100, -1300];], and satellite centroid parameter (0, 0), the vector diagram of the thrust-resultant force variation relationship of the faulty thruster is drawn, and the real-time variation model of thrust-resultant force of a single electric thruster is shown in Figures 4-7. The relationship between thrust and resultant force direction variation is shown in Figure 8. Figure 9 shows the resultant force tolerance range calculated by Monte Carlo. The fault detection curve of thruster 1 under fault-free conditions is shown in Figure 10, and the fault detection curves of thruster 1 under fault modes 1 to 3 are shown in Figures 11-13.

[0157] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting thrust decrease in a transfer orbit electric propulsion satellite, characterized in that, include: S1: Acquire satellite data; S2: Based on the satellite data, establish a real-time thrust-resultant force variation model for a single electric thruster; S3: Based on the real-time thrust-resultant force variation model for a single electric thruster, calculate the satellite resultant force tolerance range according to the thrust tolerance range of the electric thruster; S4: Determine whether the actual resultant force on the satellite is within the satellite thrust resultant force tolerance range. If so, there is no fault; otherwise, proceed to S5. S5: Based on the magnitude and direction of the actual resultant force acting on the satellite, the installation location of the faulty electric thruster is determined using the real-time thrust-resultant force variation model of the single electric thruster; S6: Based on the magnitude of the resultant force at different times within the satellite's operating time range and the installation location of the faulty electric thruster, the fault mode of the faulty electric thruster is determined using the fault mode function of the faulty electric thruster, and a thrust curve of the faulty thruster is generated; S2 includes: S21: Using the real-time centroid position of the satellite as a reference point, the relative installation position of the electric thruster under the transfer orbit is determined according to the actual installation location of the electric thruster; S22: Based on the relative installation position of the electric thruster under the transfer orbit, a thrust model of the electric thruster under the transfer orbit is established; S23: Based on the thrust model of the electric thruster under the transfer orbit, and based on the calculation rules of resultant force and resultant torque, a single electric thruster thrust-resultant force calculation relationship model under the transfer orbit is established; 24: Based on the thrust-resultant force calculation model of the single electric thruster under the transfer orbit, calculate the magnitude and direction of the resultant force vector; S25: Control the working state of the single electric thruster to change from 0-100%, and establish a thrust-resultant force change model of the single electric thruster based on the thrust-resultant force calculation model of the single electric thruster and the magnitude and direction of the resultant force vector; In S21, the actual installation position of the electric thruster is determined by the thruster layout scheme and the thruster configuration scheme; The thruster layout scheme is: four electric thrusters are installed on the satellite back floor through a vector adjustment mechanism, the thrust direction is perpendicular to the back floor, and the layout of the four electric thrusters on the back floor is rectangular; The thruster configuration scheme is: four thrusters are symmetrically installed on the satellite back floor, two on the south side of the satellite and two on the north side; In S23, the thrust-resultant force calculation model of the single electric thruster under the transfer orbit is: Among them, F1-F4 represent the thrust of each of the four thrusters, F 合 The resultant force is the net force; the direction of the net force is calculated considering the influence of torque, which is the result of normalizing the superimposed torque of the directions of the four thrusts; in S24, the direction of the net force vector is represented by the elevation angle theta and the deflection angle alpha of the net force direction; the relationship between theta, alpha and x, y, z is as follows: Where x, y, and z are respectively referred to as the lateral, longitudinal, and vertical installation positions of the electric thruster; theta is the angle between the thrust direction and the Y-axis, and alpha is the angle between the projection of the thrust direction onto the XOZ plane and the Z-axis; in S4, the fault model is used to determine whether the actual resultant force on the satellite is within the tolerance range of the satellite thrust resultant force. The fault model is: Among them, F percent The value represents the degree of failure of the faulty thruster, ranging from 0 to 100. A value of 100 indicates that the thruster is not faulty. percent / 100 represents the current thrust as a percentage of the fault-free condition, and t is the current operating time. rand The intermediate operating time of the randomly generated electric thruster is used to simulate the thrust variation of a faulty thruster.

2. The method for detecting thrust reduction in a transfer orbit electric propulsion satellite according to claim 1, characterized in that, In S1, the satellite data includes: the actual installation location of the electric thruster, the rated thrust of the electric thruster, the thrust tolerance range of the electric thruster, the fault mode function data, and real-time data; the real-time data includes the real-time position of the satellite's center of mass and the actual resultant force data acting on the satellite.

3. The method for detecting thrust decrease in a transfer orbit electric propulsion satellite according to claim 1, characterized in that, The S3 This includes: S31: Based on the thrust tolerance range of the thrusters, using the Monte Carlo method, simulate 10,000 times to randomly generate thrust within the tolerance range of all thrusters, forming a thrust matrix; S33: Based on the thrust matrix and the thrust-resultant force calculation relationship model of a single electric thruster, calculate the magnitude and direction of the resultant force; S34: Based on the magnitude and direction of the resultant force from the 10,000 Monte Carlo simulations, estimate the tolerance range of the resultant force of the electric thrusters when the electric thruster fault is within the tolerance range.

4. The method for detecting thrust reduction in a transfer orbit electric propulsion satellite according to claim 1, characterized in that, S6 includes: S61: determining the faulty electric thruster based on its installation location; S62: obtaining the magnitude of the resultant force at different times within the satellite's operating time range; S63: determining the fault mode of the faulty electric thruster using a fault mode function based on the magnitude of the resultant force at different times within the satellite's operating time range; S64: generating the thrust curve of the faulty electric thruster based on its fault mode.

5. The method for detecting thrust decrease in a transfer orbit electric propulsion satellite according to claim 4, characterized in that, The faulty electric thruster includes four fault modes, where the thrust of the thruster varies with the operating time t, which is between 0 and 100 seconds: Fault mode 1: The thruster's operating state abruptly changes from 100% to 0; Fault mode 2: The thruster's operating state gradually changes from 100% to 0; Fault mode 3: The thruster's operating state changes from 100% to x% and then remains unchanged; Fault mode 4: The thruster's operating state changes from 100% to x%, and then from x% back to 100%.

6. The method for detecting thrust decrease in a transfer orbit electric propulsion satellite according to claim 4, characterized in that, The fault mode functions include: Wherein, 1, 2, 3, and 4 represent four different fault modes, and 1 represents the thrust suddenly becoming 0; 2 represents the thrust gradually becoming 0; 3 represents the thrust gradually becoming x% and then remaining unchanged; 4 represents the thrust gradually becoming x% and then returning to 100%. totalforce(end) represents the final value of the resultant force during the working time of the electric thruster. totalforce represents the rated resultant force under fault-free conditions. totalforce(1) represents the resultant force at the initial moment within the working time range. totalforce(500) represents the resultant force at the middle moment within the working time range.

7. A system for detecting thrust decrease in a transfer orbit electric propulsion satellite based on any one of claims 1-6, characterized in that, The system includes: a data acquisition module for acquiring satellite data; a model building module for establishing a real-time thrust-resultant force variation model for a single electric thruster based on the satellite data; a resultant force tolerance range calculation module for calculating the satellite resultant force tolerance range based on the single electric thruster's real-time thrust-resultant force variation model and the thrust tolerance range of the electric thruster; a fault judgment module for determining whether the actual resultant force on the satellite is within the satellite thrust resultant force tolerance range; a fault location determination module for determining the installation location of the faulty electric thruster based on the actual resultant force on the satellite and using the single electric thruster's real-time thrust-resultant force variation model; and a curve generation module for determining the fault mode of the faulty electric thruster and generating a faulty thruster thrust curve based on the resultant force value at different times within the satellite's operating time range and the installation location of the faulty electric thruster, using the fault mode function of the faulty electric thruster.

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