Method for real-time adjustment of parallel tank discharge to reduce disturbance torque of orbit change engine

Abstract

The present invention relates to a method for real-time regulation of parallel tank discharge to reduce the disturbance torque of the orbit change engine, the steps include: obtaining satellite input information; obtaining a matrix reflecting the tank installation position and system mixing ratio, a thrust vector in a satellite mechanical coordinate system, and information on the engine thrust action point in a satellite mechanical coordinate system; determining the tank propellant loading, satellite mass center, engine thrust vector and the coordinates of the intersection of the XY plane at the satellite mass center at the beginning of the orbit change; iteratively calculating the satellite X and Y direction mass center adjustment target values ​​during the orbit change process in time steps; when the satellite changes orbit, according to the determined tank drop pressure / constant pressure mode, operating related valves on orbit, and regulating the parallel tank discharge in real time to reduce the disturbance torque of the orbit change engine. The present invention comprehensively considers factors such as engine performance parameters and satellite installation accuracy errors, closely follows engineering practice, is convenient for engineering application and helps to improve calculation accuracy.

Description

Technical Field

[0001] The invention relates to a method for real-time regulation of parallel tank discharge to reduce the disturbance torque of an orbit change engine, and belongs to the technical field of satellite orbit change. Background Art

[0002] The satellite orbit change engine is installed on the outer surface of the satellite's cabin. Its thrust vector generally coincides with a certain geometric center axis of the satellite. The satellite's orbit change flight direction is also the direction of the thrust vector.

[0003] In recent years, with the increase in satellite propellant carrying capacity and the optimization of satellite configuration, more and more bipropellant chemical propulsion system satellites have adopted the parallel tank solution, that is, the oxidizer and the fuel are each loaded in two tanks, and the two tanks discharge propellant at the same time when the satellite changes orbit. The two tanks with the same propellant are symmetrically arranged on both sides of the geometric center axis of the satellite's orbit change flight direction. When the two tanks discharge propellant at equal flow rates, the satellite's center of mass is basically near the geometric center axis of the orbit change flight direction, that is, the thrust vector, which can ensure the stability of the satellite's attitude during orbit change.

[0004] However, affected by factors such as the installation error of the orbit change engine and the deviation of the propellant discharge in the tank, in actual engineering, the satellite's center of mass does not strictly pass through the thrust vector when the satellite changes its orbit, but is at a small distance from the thrust vector. This causes the thrust of the orbit change engine to generate an interference torque, which will affect the attitude stability of the satellite when it changes its orbit. The attitude control thruster or other components need to work extra to generate attitude control torque to offset the interference torque in order to maintain the satellite's attitude stability, which increases the risk of satellite orbit changes.

[0005] It is precisely because the two parallel tanks of the parallel tank satellite have unbalanced discharge that the satellite's center of mass will be offset, generating interference torque on the satellite's orbit change flight. Therefore, it is necessary to control the balanced discharge of the parallel tanks and the satellite's center of mass.

[0006] In the prior art methods for adjusting and balancing the emissions of parallel tanks, only the emissions of the parallel tanks can be adjusted and balanced, and the relationship between the balanced emissions and the satellite's center of mass and the interference torque cannot be established. There is no method for reducing the interference torque of the orbit change engine by adjusting the emissions of the parallel tanks. Summary of the invention

[0007] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to propose a method for real-time regulation of the discharge of parallel tanks to reduce the interference torque of the orbit change engine, to independently control the opening and closing of the valve at the gas port end of each tank in a time-sharing manner during the orbit change of the parallel tank satellite, to regulate the air cushion pressure of each tank, and then to regulate the propellant discharge flow rate, the residual mass of the propellant and the satellite center of mass of each tank, so as to make the satellite center of mass close to the thrust vector of the orbit change engine during the orbit change process, thereby achieving the effect of reducing the interference torque of the orbit change engine.

[0008] The solution of the present invention is:

[0009] A method for real-time adjustment of parallel tank discharge to reduce the disturbance torque of a trajectory change engine comprises the following steps:

[0010] S1. Obtain satellite input information, including satellite dry mass and center of mass, tank and engine performance parameters and on-board installation parameters, propellant density, tank pressure drop, and tank upstream and downstream pressure information;

[0011] S2, obtaining a matrix reflecting the tank installation position and system mixing ratio, a thrust vector in the satellite mechanical coordinate system, and information on the engine thrust application point in the satellite mechanical coordinate system;

[0012] S3, determining the amount of propellant in the tank, the satellite mass center, the engine thrust vector and the coordinates of the intersection of the XY plane at the satellite mass center at the start of the orbit change;

[0013] S4, iteratively calculating the satellite X and Y direction center of mass adjustment target values, the propellant loading adjustment target value, the flow rate of each tank, the tank pressure drop / constant pressure mode, and the air cushion pressure during the orbit change process in time steps, and finally making the satellite X and Y direction center of mass gradually approach the intersection of the engine thrust vector and the XY plane at the satellite center of mass by controlling the tank pressure drop / constant pressure mode, so that the interference torque of the orbit change engine is gradually reduced;

[0014] S5. When the satellite changes orbit, according to the pressure drop / constant pressure mode of the tank determined by S4, the relevant valves are operated on-orbit to adjust the parallel tank discharge in real time to reduce the interference torque of the orbit change engine.

[0015] Furthermore, in S2, an intermediate variable matrix reflecting the tank installation position and the system mixing ratio is obtained.

[0016]

[0017] Among them, η is the orbit change engine mixing ratio, and XY_t is the X and Y coordinates of the central axis of the tank in the satellite mechanical coordinate system.

[0018] Furthermore, in S2, the vector of the engine thrust in the engine body coordinate system is

[0019] F_e=F·[cos(α),sin(α)·cos(γ),sin(α)·sin(γ)] T , where F is the thrust of the orbit change engine, α is the thrust deflection angle of the orbit change engine, and γ is the thrust vector deflection position angle.

[0020] Furthermore, in S3, the amount of propellant in each tank at the start of the orbit change is

[0021]

[0022] Among them, A is the intermediate variable matrix reflecting the tank installation position and the system mixing ratio, m_s_3 is the satellite launch mass, m_s_2 is the weight of the satellite stem, XYZ_s_2 is the coordinate of the satellite stem center of mass in the satellite mechanical coordinate system, and XY_s_T is the X and Y coordinates of the satellite center of mass in the satellite mechanical coordinate system at the beginning of the satellite orbit change.

[0023] Furthermore, in S3, the X, Y, and Z coordinates of the satellite center of mass in the satellite mechanical coordinate system at the beginning of the satellite orbit change are

[0024] XYZ_s_T=(m_s_2*XYZ_s_2+m_p_T*XYZ_t) / m_s_3,

[0025] Among them, m_s_2 is the weight of the satellite stem, XYZ_s_2 is the coordinate of the satellite stem mass center in the satellite mechanical coordinate system, m_p_T is the propellant filling amount of each tank at the beginning of the orbit change, XYZ_t is the X, Y, and Z coordinates of the propellant mass center, and m_s_3 is the satellite launch mass.

[0026] Furthermore, in S3, the intersection coordinates of the engine thrust vector and the XY plane at the satellite mass center at the start of the orbit change are XYZ_P7 = (P_s + b*F_s) T

[0027] Among them, P_s is the vector of the engine thrust action point in the satellite mechanical coordinate system, F_s is the thrust vector in the satellite mechanical coordinate system when the engine is working, and b is an intermediate variable.

[0028] The beneficial effects of the present invention compared with the prior art are:

[0029] (1) The present invention is based on the current hardware configuration of parallel tank satellites, and can adjust the tank discharge flow, satellite center of mass and orbit change engine interference torque by real-time controlling the opening and closing of the self-locking valve upstream of the tank;

[0030] (2) The present invention discretizes the orbit change process in time and actively applies adjustment measures during the orbit change process to make the satellite's center of mass gradually approach the thrust vector of the orbit change engine, thereby ensuring the stability of the chemical propulsion system during the adjustment process and reducing the interference torque of the orbit change engine;

[0031] (3) The calculation links of each part of the present invention are fully parameterized, and an iterative cycle and a judgment branch calculation method are introduced, which facilitates the compilation of calculation programs and thus reduces the calculation time;

[0032] (4) The present invention comprehensively considers factors such as engine performance parameters and satellite installation accuracy errors, closely follows engineering practice, is convenient for engineering application, and helps improve calculation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the parallel tank satellite configuration;

[0034] Figure 2 This is the schematic diagram of the parallel tank chemical propulsion system;

[0035] Figure 3 This is the satellite centroid relationship diagram in the XY plane. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the embodiments.

[0037] Attached Figure 1 It is a schematic diagram of the parallel tank satellite configuration.

[0038] A parallel tank satellite generally contains 4 tanks, including 2 oxygen tanks and 2 fuel tanks, namely oxygen tank a MON-a, oxygen tank b MON-b, fuel tank a MMH-a, and fuel tank b MMH-b. The engine is arranged on the satellite bottom plate.

[0039] Attached Figure 2 This is the schematic diagram of a parallel tank chemical propulsion system. The names of each unit are shown in the legend.

[0040] Attached Figure 3 It is the satellite centroid relationship diagram in the XY plane.

[0041] Point 1 is the satellite mass center at the beginning of the satellite orbit change, point 3 is the intersection of the engine thrust vector and the XY plane at the satellite mass center at the beginning of the orbit change, and point 2 is the position of the satellite mass center, the intersection of the engine thrust vector and the XY plane at the satellite mass center after time step t_s and time step number K. During the orbit change process, the satellite mass center gradually approaches the intersection of the engine thrust vector and the XY plane at the satellite mass center.

[0042] The method of real-time adjustment of parallel tank discharge to reduce the disturbance torque of the orbit change engine includes two parts. One is the parallel tank working mode, satellite center of mass, and orbit change engine disturbance torque calculation. The other is the on-orbit operation of the satellite during orbit change.

[0043] Part 1 Parallel tank working mode, satellite center of mass, and orbit change engine interference torque calculation

[0044] The calculation of parallel tank working mode, satellite mass center, and orbit change engine interference torque includes five steps, as follows:

[0045] Calcu_1: Get input parameters

[0046] Through experiments, tests and simulations, the input parameters are obtained, including the satellite's dry mass and center of mass, the performance parameters of the tank and engine and the on-board installation parameters, the density of the propellant, the tank pressure drop, the upstream and downstream pressures of the tank, etc. The input parameters are used as known quantities in subsequent calculation links.

[0047] a) The mixing ratio η of the orbit-changing engine.

[0048] b) The measured volume V_t of the tank (the four values ​​in the parameters are the values ​​of oxygen tank a, oxygen tank b, fuel tank a, and fuel tank b respectively), the X and Y coordinates XY_t of the tank center axis (parallel to the Z axis of the satellite mechanical coordinate system) in the satellite mechanical coordinate system, the density ρ_p of the propellant, and the temperature T_He of the helium in the tank.

[0049] c) The liquid centroid height Z_p at different filling volumes of the tank includes multiple sets of corresponding relationships between different specific filling volumes and liquid centroid heights (V_p_i, Z_p_i), which can be used to interpolate and calculate the liquid centroid height at any filling volume.

[0050] d) Tank pressure drop Δ_P, gas pressure at the inlet of the upper port valve of the tank P_g, and pressure at the downstream confluence point of the parallel tanks P_m.

[0051] e) Satellite launch mass m_s_3.

[0052] f) The weight of the satellite dry star (without propellant) is m_s_2, and the coordinates of the satellite dry star's center of mass in the satellite's mechanical coordinate system are XYZ_s_2.

[0053] g) orbit change engine thrust F, orbit change engine thrust deflection angle α, thrust vector lateral displacement angle β, thrust vector deflection position angle γ, thrust vector lateral displacement δ, length from mounting surface to nozzle l_1, mass flow rate f_e of propellant consumed when orbit change engine is ignited.

[0054] h) The angle matrix Г between the axes of the precision measuring mirror coordinate system and the axes of the satellite mechanical coordinate system, and the coordinates of the engine nozzle center in the satellite mechanical coordinate system Δ=[Δ1,Δ2,Δ3].

[0055] i) The X and Y coordinates of the satellite's center of mass in the satellite's mechanical coordinate system at the start of the satellite orbit change.

[0056] j) The time step of the solution is t_s, the total time steps of the orbit change is K, and the helium pressure iteration convergence error is d.

[0057] Calcu_2: Get intermediate variables

[0058] The matrix reflecting the tank installation position and system mixing ratio, the thrust vector in the satellite mechanical coordinate system, and the engine thrust application point in the satellite mechanical coordinate system are preliminarily obtained to facilitate use in subsequent calculation links.

[0059] a) Obtain an intermediate variable matrix A reflecting the tank installation location and system mixing ratio.

[0060]

[0061] b) Calculate the engine thrust vector F_e in the engine body coordinate system.

[0062] F_e=F·[cos(α),sin(α)·cos(γ),sin(α)·sin(γ)] T (2)

[0063] c) The coordinate rotation transformation matrix T between the engine precision measuring mirror coordinate system and the satellite mechanical coordinate system.

[0064]

[0065] Where ξ1, ψ1, υ1, etc. are the elements of the angle matrix Г between the axes of the precision mirror coordinate system and the axes of the satellite mechanical coordinate system.

[0066] d) The thrust vector F_s in the satellite mechanical coordinate system when the engine is working.

[0067] F_s=T·F_e (4)

[0068] e) The position coordinate P_c of the engine thrust action point in the engine precision measuring mirror coordinate system.

[0069] P_c=[0,δ·cosβ,δ·sinβ] T +[l_1,0,0] T (5)

[0070] f) The vector P_s of the engine thrust action point in the satellite mechanical coordinate system.

[0071] P_s=T·P_c+[Δ1,Δ2,Δ3] T (6)

[0072] Calcu_3: Analysis of the initial state of orbit change

[0073] The amount of propellant in the tank, the satellite's center of mass, the coordinates of the intersection of the engine thrust vector and the XY plane at the satellite's center of mass at the beginning of the orbit change are calculated as the initial values ​​for the subsequent orbit change process analysis.

[0074] a) Assume that the satellite propellant is not consumed when the orbit change begins and the propellant mass is the same as when the satellite is launched.

[0075] Calculate the propellant filling amount m_p_T of each tank at the beginning of the orbit change.

[0076]

[0077] b) Calculate the propellant volume V_p in the tank at the beginning of the orbit change.

[0078] V_p=m_p_T / ρ_p (8)

[0079] c) Assume that the X and Y center of mass of the propellant in the tank is on the central axis of the tank, that is, the X and Y center of mass coordinates of the propellant are XY_t.

[0080] d) Using V_p as input, interpolate and calculate the Z-axis center of mass of the propellant in each tank, and integrate the data into the X, Y, and Z-axis center of mass coordinates of the propellant, XYZ_t.

[0081] e) Calculate the X, Y, and Z coordinates XYZ_s_T of the satellite's center of mass in the satellite's mechanical coordinate system at the beginning of the satellite's orbit change.

[0082] XYZ_s_T=(m_s_2*XYZ_s_2+m_p_T*XYZ_t) / m_s_3 (9)

[0083] f) Define vector N = [0, 0, XYZ_s_T(3)], where XYZ_s_T(3) is the Z coordinate of the satellite's center of mass.

[0084] g) Calculate the intermediate variable b.

[0085] b=(N-P_sT)·VPT / (VP·F_s) (10)

[0086] In the formula, vector VP=[0,0,1].

[0087] h) Calculate the coordinates of the intersection of the engine thrust vector and the XY plane at the satellite's center of mass at the beginning of the orbit change, XYZ_P7.

[0088] XYZ_P7=(P_s+b*F_s) T (11)

[0089] Calcu_4: Track change process analysis

[0090] The satellite's X and Y center of mass adjustment target values, propellant loading adjustment target values, flow rate of each tank, tank drop pressure / constant pressure mode, air cushion pressure, etc. are calculated and iterated step by step in time steps during the orbit change process. By controlling the tank drop pressure / constant pressure mode, the satellite's X and Y center of mass gradually approaches the intersection of the engine thrust vector and the XY plane at the satellite's center of mass, that is, the interference torque of the orbit change engine is gradually reduced.

[0091] a) Set the variable XYZ_P7_To to store the coordinates of the intersection of the engine thrust vector and the XY plane at the satellite's center of mass during the orbit change process, and make the values ​​of the first row and columns of XYZ_P7_To the same as those of XYZ_P7.

[0092] b) Set the variable Q_t to store the air cushion pressure of each tank during the track change process, and make the values ​​of the first row and columns of Q_t the same as the gas pressure P_g at the inlet of the valve on the upper port of the tank.

[0093] c) Set the variable i_1 to store the number of the time step of the track change process, and let i_1 be 1.

[0094] d) Calculate the satellite propellant consumption m_p_xh and remaining amount m_p_sy at the end of the i_1th time step.

[0095] m_p_xh=i_1*t_s*f_e (12)

[0096] m_p_sy=m_s_3-m_s_2-m_p_xh (13)

[0097] e) Calculate the end time of the i_1th time step. The satellite's X and Y centroids need to be adjusted to the target value XY_P8_To.

[0098] XY_P8_To(i_1,1:3)=[XYZ_s_T(1)+(XYZ_P7_To(i_1,1)-XYZ_s_T(1))*i_1 / K,XYZ_s_T(2)+(XYZ_P7_To(i_1,2)-XYZ_s_T(2))*i_1 / K] (14)

[0099] f) Calculate the end time of the i_1th time step. The propellant loading of each tank needs to be adjusted to the target value m_p_To_mb.

[0100]

[0101] g) Calculate the flow ratio λ_o of the two oxygen boxes and the flow ratio λ_f of the two fuel boxes at the i_1th time step.

[0102]

[0103]

[0104] h) Calculate the flow rate f_t(i_1,1:4) of each tank at the i_1th time step.

[0105] f_t(i_1,1:4)=[f_e*η / (1+η)*λ_o(i_1) / (1+λ_o(i_1)),f_e*η / (1+η) / (1+λ_o (i_1)),f_e / (1+η)*λ_f(i_1) / (1+λ_f(i_1)),f_e / (1+η) / (1+λ_f(i_1))](18)

[0106] i) Calculate the actual remaining amount of propellant m_p_To_sj(i_1,1:4) and the remaining volume V_p_To_sj(i_1,1:4) of each tank at the i_1th time step.

[0107]

[0108] V_p_To_sj(i_1,1:4)=m_p_To_sj(i_1,1:4) / ρ_p (20)

[0109] j) Determine whether the tank is working at a falling pressure or a constant pressure in the next time step. Set the variable j_2 to store the tank number and set j_2 to 1.

[0110] k) If m_p_To_mb(i_1,j_2) is greater than or equal to m_p_To_sj(i_1,j_2), execute step l_y), otherwise execute step l_n).

[0111] l_y) Set the pressure drop / constant pressure mode flag L(i_1+1,j_2) of the j_2 tank to 1 at the i_1+1 time step. And execute steps l_y_1) to l_y_5) in sequence.

[0112] l_y_1) Calculate the helium compression factor Z, helium density ρ_He, and helium mass m_He.

[0113] Z(i_1,j_2)=1+1.9572205*Q_t(i_1,j_2)*T_He-1.062213 (21)

[0114] ρ_He(i_1,j_2)=Q_t(i_1,j_2)*4 / [Z(i_1,j_2)*T_He*8314] (22)

[0115] m_He(i_1,j_2)=ρ_He(i_1,j_2)*[V_t(j_2)-V_p_To_sj(i_1,j_2)] (23)

[0116] l_y_2) Set j_3 to 1.

[0117] l_y_3) Calculate the iterative pressure P_cs.

[0118] P_cs=j_3*P_max / 10000 (24)

[0119] Here, P_max is the maximum value of the gas pressure P_g at the inlet of the valve at the upper port of the tank.

[0120] l_y_4) Calculate the iterative helium compression factor Z_cs, iterative helium density ρ_He_cs, and iterative helium mass m_He_cs.

[0121] Z_cs=1+1.9572205*P_cs*T_He-1.062213 (25)

[0122] ρ_He_cs=P_cs*4 / [Z_cs*T_He*8314] (26)

[0123] m_He_cs=ρ_He_cs*[V_t(j_2)-V_p_To_sj(i_1,j_2)] (27)

[0124] 1_y_5) is used for judgment: If the following equation is established, the air cushion pressure Q_t(i_1+1,j_2) of the j_2 tank at the i_1+1 time step is set to P_cs, and the loop is exited. Otherwise, j_3 is incremented by 1 and the execution of step 1_y_3) is returned.

[0125] |m_He_cs-m_He(i_1,j_2)| / m_He(i_1,j_2) <d (28)

[0126] l_n) sets the pressure drop / constant pressure mode flag L(i_1+1,j_2) of the j_2th tank at the i_1+1th time step to 0, and sets the air cushion pressure Q_t(i_1+1,j_2) of the j_2th tank at the i_1+1th time step to Q_t(1,j_2).

[0127] m) Using V_p_To_sj as input, interpolate and calculate the Z-axis center of mass of the propellant in each tank, and integrate the data into the X, Y, and Z-axis center of mass coordinates of the propellant, XYZ_t.

[0128] n) Calculate the X, Y, and Z coordinates of the satellite center of mass at the i_1th time step in the satellite mechanical coordinate system. XYZ_s_To(i_1,1:3)=[m_s_2*XYZ_s_2+m_p_To_sj(i_1,1:4)*XYZ_t] / (m_s_3-m_p_xh)(29)

[0129] o) Calculate the vector N = [0,0,XYZ_s_To(i_1,3)], where XYZ_s_To(i_1,3) is the Z coordinate of the satellite's center of mass.

[0130] p) Calculate the intermediate variable b.

[0131] b=(N-P_sT)*VPT / (VP*F_s) (30)

[0132] q) Calculate the coordinates of the intersection of the engine thrust vector and the XY plane at the satellite's center of mass at the i_1+1th time step XYZ_P7_To(i_1+1,1:3).

[0133] XYZ_P7_To(i_1+1,1:3)=(P_s+b*F_s) T (31)

[0134] r) Calculate the disturbance torque components M_e_i(i_1,1:3) of the orbit change engine around the X, Y, and Z axes at the i_1th time step.

[0135] M_e_i(i_1,1:3)=F_s×[P_s-XYZ_s_To(i_1,:)] (32)

[0136] s) Calculate the combined value of the disturbance torque Me(i_1) of the orbit change engine at the i_1th time step.

[0137]

[0138] t) Add 1 to i_1, return to step d), and continue executing until i_1 reaches K.

[0139] Calcu_5: Summarize calculation results

[0140] The calculation results directly related to the on-orbit operation during the satellite orbit change are summarized as the input of the on-orbit operation during the satellite orbit change.

[0141] a) Output the drop pressure / constant pressure mode flag L of each tank at each time step during the track change process.

[0142] b) Output the satellite center of mass XYZ_s_To and the intersection coordinates XYZ_P7_To of the engine thrust vector and the XY plane at the satellite center of mass at each time step of the orbit change process.

[0143] c) Output the disturbance torque components T_e_i and the synthetic value T_e of the orbit change engine around the X, Y, and Z axes at each time step of the orbit change process.

[0144] Part_2 On-orbit operations when satellite changes orbit

[0145] According to the calculation results of Part_1, the relevant valves are operated on-orbit according to the time step when the satellite changes its orbit, so that the parallel tank discharge can be adjusted in real time to reduce the interference torque of the orbit change engine. It includes 6 links, as follows:

[0146] a) Before the track change begins, ensure that the two self-locking valves downstream of the parallel tank are not opened at the same time (here, the self-locking valves LV1 and LV2 are opened, and the self-locking valves LV3 and LV4 are closed).

[0147] b) Before starting the track change, ensure that the self-locking valves (LV5 to LV7) upstream of the parallel tanks are all in the closed state.

[0148] c) At the beginning of the orbit change, a short time (for example, 1 second) before the orbit change engine is ignited, open all the self-locking valves downstream of the parallel tanks (the self-locking valves LV3 and LV4 in this example).

[0149] d) The orbit change engine ignites and the satellite begins to change its orbit.

[0150] e) After the first time step t_s, read the value of the pressure drop / constant pressure mode flag L of each tank at each time step of the track change process in turn. If the value of the pressure drop / constant pressure mode flag of the j_2 tank at the i_1 time step, that is, L(i_1,j_2) is 0, the self-locking valve upstream of the j_2 tank is opened at the i_1 time step; if L(i_1,j_2) is 1, the self-locking valve upstream of the j_2 tank is closed at the i_1 time step.

[0151] f) After completing K time steps, the adjustment work is completed.

[0152] The present invention is based on the current hardware configuration of parallel tank satellites. By real-time controlling the opening and closing of the self-locking valve upstream of the tank, the adjustment of the tank discharge flow, the satellite center of mass and the interference torque of the orbit change engine can be completed, and the requirements for the software and hardware on the satellite are relatively low.

[0153] The present invention performs time discretization processing on the orbit change process, and actively applies adjustment measures during the orbit change process to make the satellite's center of mass gradually approach the thrust vector of the orbit change engine, thereby ensuring the stability of the chemical propulsion system during the adjustment process and ensuring the reduction of the interference torque of the orbit change engine.

[0154] The calculation links of each part of the present invention are fully parameterized, and calculation methods such as iterative loops and judgment branches are introduced to facilitate the compilation of calculation programs, thereby reducing the calculation time.

[0155] The present invention comprehensively considers factors such as engine performance parameters and satellite installation accuracy errors, closely follows engineering practice, is convenient for engineering application and helps to improve calculation accuracy.

[0156] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for real-time adjustment of parallel tank discharge to reduce the disturbance torque of the orbit change engine, characterized in that the steps include: S1. Obtain satellite input information, including satellite dry mass and center of mass, tank and engine performance parameters and on-board installation parameters, propellant density, tank pressure drop, and tank upstream and downstream pressure information; S2, obtaining a matrix reflecting the tank installation position and system mixing ratio, a thrust vector in the satellite mechanical coordinate system, and information on the engine thrust application point in the satellite mechanical coordinate system; In S2, the intermediate variable matrix reflecting the tank installation location and system mixing ratio is obtained Wherein, η is the orbit change engine mixing ratio, XY_t is the X and Y coordinates of the tank center axis in the satellite mechanical coordinate system; S3, determining the amount of propellant in the tank, the satellite mass center, the engine thrust vector and the coordinates of the intersection of the XY plane at the satellite mass center at the start of the orbit change; In S3, the amount of propellant in each tank at the start of the orbit change Among them, A is the intermediate variable matrix reflecting the tank installation position and system mixing ratio, m_s_3 is the satellite launch mass, m_s_2 is the weight of the satellite stem, XYZ_s_2 is the coordinate of the satellite stem center of mass in the satellite mechanical coordinate system, and XY_s_T is the X and Y coordinates of the satellite center of mass in the satellite mechanical coordinate system at the beginning of the satellite orbit change; S4, iteratively calculating the satellite X and Y direction center of mass adjustment target values, the propellant loading adjustment target value, the flow rate of each tank, the tank pressure drop / constant pressure mode, and the air cushion pressure during the orbit change process in time steps, and finally making the satellite X and Y direction center of mass gradually approach the intersection of the engine thrust vector and the XY plane at the satellite center of mass by controlling the tank pressure drop / constant pressure mode, so that the interference torque of the orbit change engine is gradually reduced; S5. When the satellite changes orbit, according to the pressure drop / constant pressure mode of the tank determined by S4, the relevant valves are operated on-orbit to adjust the parallel tank discharge in real time to reduce the interference torque of the orbit change engine.

2. The method for real-time adjustment of parallel tank discharge to reduce the disturbance torque of the track change engine according to claim 1, characterized in that: In S2, the engine thrust vector in the engine body coordinate system is F_e=F·[cos(α),sin(α)·cos(γ),sin(α)·sin(γ)] T , where F is the thrust of the orbit change engine, α is the thrust deflection angle of the orbit change engine, and γ is the thrust vector deflection position angle.

3. The method for real-time adjustment of parallel tank discharge to reduce the disturbance torque of the track change engine according to claim 1, characterized in that: In S3, the X, Y, and Z coordinates of the satellite's center of mass in the satellite's mechanical coordinate system at the beginning of the satellite's orbit change XYZ_s_T=(m_s_2*XYZ_s_2+m_p_T*XYZ_t) / m_s_3, Among them, m_s_2 is the weight of the satellite stem, XYZ_s_2 is the coordinate of the satellite stem mass center in the satellite mechanical coordinate system, m_p_T is the propellant filling amount of each tank at the beginning of the orbit change, XYZ_t is the X, Y, and Z coordinates of the propellant mass center, and m_s_3 is the satellite launch mass.

4. The method for real-time adjustment of parallel tank discharge to reduce the disturbance torque of the orbit change engine according to claim 1, characterized in that: In S3, the intersection coordinates of the engine thrust vector and the XY plane at the satellite mass center at the beginning of the orbit change are XYZ_P7 = (P_s + b*F_s) T Among them, P_s is the vector of the engine thrust action point in the satellite mechanical coordinate system, F_s is the thrust vector in the satellite mechanical coordinate system when the engine is working, and b is an intermediate variable.

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