阅读说明：本技术 一种电推力器位置保持推力分配方法和系统 (Method and system for distributing thrust for maintaining position of electric thruster ) 是由 马雪 郭廷荣 韩冬 林波 耿洁 黎飞 王建花 周中泽 文闻 孙静 李巍 刘蕊 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种电推力器位置保持推力分配方法和系统,该方法包括：根据位置保持漂移率控制量,确定两台电推力器的法向指向档位；根据确定的两台电推力器的法向指向档位,分别计算得到第一电推力器的目标推力方向[X-(n),Y-(n),Z-(n)]和开机时长Δt-(n),以及第二电推力器的目标推力方向[X-(s),Y-(s),Z-(s)]和开机时长Δt-(s)；计算得到第一理论矢量调节机构转速ω-(n)和第二理论矢量调节机构转速ω-(s)；将[X-(n),Y-(n),Z-(n)]和Δt-(n)分配给第一电推力器,将[X-(s),Y-(s),Z-(s)]和Δt-(s)分配给第二电推力器,将ω-(n)分配给第一矢量调节机构,将ω-(s)分配给第二矢量调节机构。本发明采用完全解析的方法计算电推力器开机时长和速度增量,充分考虑了实际工程约束,可满足静止轨道卫星的位置保持任务需求。(The invention discloses a method and a system for distributing thrust of position maintenance of an electric thruster, wherein the method comprises the following steps: determining normal pointing gears of the two electric thrusters according to the position holding drift rate control quantity; respectively calculating to obtain a target thrust direction [ X ] of the first electric thruster according to the determined normal pointing gears of the two electric thrusters n ,Y n ,Z n ]And a boot time period Δ t n And a target thrust direction [ X ] of the second electric thruster s ,Y s ,Z s ]And a boot time period Δ t s (ii) a Calculating to obtain the rotating speed omega of the first theoretical vector adjusting mechanism n And a second theoretical vector adjusting mechanism rotating speed omega s (ii) a Will [ X ] n ,Y n ,Z n ]And Δ t n Is distributed to the first electric thruster to drive [ X s ,Y s ,Z s ]And Δ t s Is distributed to the second electric thruster to drive omega n Is assigned to a first vector adjustment mechanismω s Is assigned to the second vector adjustment mechanism. The method adopts a complete analysis method to calculate the starting time length and the speed increment of the electric thruster, fully considers the practical engineering constraint and can meet the position maintenance task requirement of the geostationary orbit satellite.)

1. A method of distributing position maintaining thrust of an electric thruster, comprising:

determining normal pointing gears of the two electric thrusters according to the position holding drift rate control quantity;

respectively calculating to obtain a target thrust direction [ X ] of the first electric thruster according to the determined normal pointing gears of the two electric thrusters_n,Y_n,Z_n]And a boot time period Δ t_nAnd a target thrust direction [ X ] of the second electric thruster_s,Y_s,Z_s]And a boot time period Δ t_s；

According to [ X ]_n,Y_n,Z_n]And [ X ]_s,Y_s,Z_s]And calculating to obtain the rotating speed omega of the first theoretical vector adjusting mechanism_nAnd a second theoretical vector adjusting mechanism rotating speed omega_s；

Will calculate the obtained [ X_n,Y_n,Z_n]And Δ t_nDistributing the calculated [ X ] to the first electric thruster_s,Y_s,Z_s]And Δ t_sDistributing the calculated omega to a second electric thruster_nAssigning the calculated ω to the first vector adjustment mechanism_sIs assigned to the second vector adjustment mechanism.

2. The method of claim 1, wherein determining the normally-oriented gears of the two electric thrusters based on the position hold drift rate control comprises:

determining a unit vector [ X, Y, Z ] of a thrust direction under a track coordinate system; the origin of the orbit coordinate system is the center of mass of the satellite, the X axis points to the advancing direction of the satellite, the Z axis points to the ground, and the Y axis, the X axis and the Z axis meet the right-hand rule;

calculating to obtain the adjusting range C of the vector adjusting mechanism_y＝Y/Z；

For the regulation range C_yN are equally divided to obtain n normal direction gears C which are arranged from small to large_ys：C_ys＝C_y1、C_y2、…、C_yn(ii) a Wherein each normal direction is towards gear C_y1、C_y2、…、C_ynThe corresponding allowable ranges of the drift rate are as follows: [ Delta DL₁,ΔDH₁]、[ΔDL₂,ΔDH₂]、…、[ΔDL_n,ΔDH_n]；

Acquiring a position holding drift rate control quantity delta D;

if Δ D ∈ [ Δ DL ]₁,ΔDH₁]Then, the normal direction gear of the two electric thrusters is determined to be C_ys＝C_y1；

If Δ D ∈ [ Δ DL ]₂,ΔDH₂]Then, the normal direction gear of the two electric thrusters is determined to be C_ys＝C_y2；

And so on;

if Δ D ∈ [ Δ DL ]_n,ΔDH_n]Then, the normal direction gear of the two electric thrusters is determined to be C_ys＝C_yn。

3. The electrical thruster position of claim 2The method for distributing the maintained thrust is characterized in that a target thrust direction [ X ] of the first electric thruster is obtained through calculation according to the determined normal pointing gears of the two electric thrusters_n,Y_n,Z_n]And a boot time period Δ t_nAnd a target thrust direction [ X ] of the second electric thruster_s,Y_s,Z_s]And a boot time period Δ t_sThe method comprises the following steps:

acquiring eccentricity control vectors delta e in the x direction and the y direction under a track coordinate system_xAnd Δ e_yAnd tilt control vectors Δ i in the x-and y-directions_xAnd Δ i_y；

According to Δ e_x、Δe_y、Δi_xAnd Δ i_yAnd calculating to obtain a speed increment VN of the first electric thruster in the x direction_xAnd a speed increment VS in the x-direction of the second electric thruster_xAnd the radial distribution identification flagV of the two electric thrusters_zAnd the radial distribution difference V_z0；

According to flagV_zAnd V_z0And calculating to obtain a speed increment VN of the first electric thruster in the y direction_yAnd velocity increment VN in the z-direction_zAnd a speed increment VS in the y-direction of the second electric thruster_yAnd z-direction velocity increment VS_z；

According to VN_y、VN_z、VS_yAnd VS_zAnd calculating to obtain a target thrust direction [ X ] of the first electric thruster_n,Y_n,Z_n]And a boot time period Δ t_nAnd a target thrust direction [ X ] of the second electric thruster_s,Y_s,Z_s]And a boot time period Δ t_s。

4. The electric thruster position maintaining thrust force distribution method of claim 3, wherein VN_xAnd VS_xThe calculation flow of (2) is as follows:

according to the nominal orbital velocity V of the geostationary orbit_sAnd the earth static orbit nominal orbit angular velocity omega_eAnd calculating to obtain a constant A, a constant B and an intermediate parameter aa:

then there are:

speed increment VN of first electric thruster in x direction_xComprises the following steps:

speed increment VS of second electric thruster in x direction_xComprises the following steps:

5. the electric thruster position holding thrust force distribution method as claimed in claim 4, wherein the flagV is a flag V_zAnd V_z0The calculation flow of (2) is as follows:

calculating to obtain an intermediate variable dV_ztemp：

According to dV_ztempDetermining flagV_z：

If dV_ztempIf the value is less than or equal to 0, flagV_z＝1

If dV_ztempIf > 0, flagV_z＝-1

Calculating to obtain a radial scoreMatch difference value V_z0：

Wherein, dV_zIndicating the difference, dV, between the radial control quantities of the two electric thrusters_z＝abs(dV_ztemp)，V_y0And the normal control quantity of the unilateral electric thruster is shown.

6. The electric thruster position maintaining thrust force distribution method of claim 5, wherein VN_y、VN_z、VS_yAnd VS_zThe calculation flow of (2) is as follows:

calculating to obtain an intermediate variable V_ytemp：

When flagV is present_zWhen 1, there are:

VN_y＝V_ytemp

VN_z＝V_z0+dV_z

VS_y＝V_y0-V_ytemp

VS_z＝V_z0

when flagV is present_zWhen-1, there is:

VN_y＝V_y0-V_ytemp

VN_z＝V_z0

VS_y＝V_ytemp

VS_z＝V_z0+dV_z。

7. the electric thruster position holding thrust force distribution method of claim 6, wherein [ X [ ]_n,Y_n,Z_n]、Δt_n、[X_s,Y_s,Z_s]And Δ t_sThe calculation process is as followsThe following:

according to VN_x、VN_yAnd VN_zCalculating to obtain [ X ]_n,Y_n,Z_n]And Δ t_n：

According to VS_x、VS_yAnd VS_zCalculating to obtain [ X ]_s,Y_s,Z_s]And Δ t_s：

Wherein F represents the thrust magnitude of the electric thruster, V_eRepresenting the electrical thruster specific impulse, mass representing the satellite mass.

8. The method of claim 7, wherein the method of assigning thrust force to position holding of an electrical thruster is based on [ X ]_n,Y_n,Z_n]And [ X ]_s,Y_s,Z_s]And calculating to obtain the rotating speed omega of the first theoretical vector adjusting mechanism_nAnd a second theoretical vector adjusting mechanism rotating speed omega_sThe method comprises the following steps:

determining a current heading [ X ] of a first electric thruster_n0,Y_n0,Z_n0]And calculating to obtain [ X ]_n,Y_n,Z_n]And [ X ]_n0,Y_n0,Z_n0]Angle theta therebetween_n；

Determining a current finger of a second electric thrusterTo [ X ]_s0,Y_s0,Z_s0]And calculating to obtain [ X ]_s,Y_s,Z_s]And [ X ]_s0,Y_s0,Z_s0]Angle theta therebetween_s；

Obtaining the rotating speed omega of the maximum theoretical vector adjusting mechanism_max；

When theta is_n≥θ_sIn time, there are:

ω_n＝ω_max

when theta is_n＜θ_sIn time, there are:

ω_s＝ω_max。

9. the method for distributing the position maintaining thrust of the electric thruster as claimed in claim 1, wherein the first vector adjusting mechanism is installed on the south side of the satellite and connected with the first electric thruster for realizing the adjustment of the thrust direction in the three directions of x, y and z; the second vector adjusting mechanism is arranged on the north side of the satellite and connected with the second electric thruster, and is used for adjusting thrust direction in the x direction, the y direction and the z direction.

10. An electric thruster position maintaining thrust distribution system, comprising:

the gear determining module is used for determining normal pointing gears of the two electric thrusters according to the position holding drift rate control quantity;

a first calculation module, configured to calculate, according to the determined normal pointing gears of the two electric thrusters, a target thrust direction [ X ] of the first electric thruster_n,Y_n,Z_n]And a boot time period Δ t_nAnd target push of the second electric thrusterDirection of force [ X ]_s,Y_s,Z_s]And a boot time period Δ t_s；

A second calculation module for calculating according to [ X_n,Y_n,Z_n]And [ X ]_s,Y_s,Z_s]And calculating to obtain the rotating speed omega of the first theoretical vector adjusting mechanism_nAnd a second theoretical vector adjusting mechanism rotating speed omega_s；

An allocation module for allocating the calculated [ X_n,Y_n,Z_n]And Δ t_nDistributing the calculated [ X ] to the first electric thruster_s,Y_s,Z_s]And Δ t_sDistributing the calculated omega to a second electric thruster_nAssigning the calculated ω to the first vector adjustment mechanism_sIs assigned to the second vector adjustment mechanism.

Technical Field

The invention belongs to the technical field of satellite attitude and orbit control, and particularly relates to a method and a system for distributing position keeping thrust of an electric thruster.

Background

At present, the electric propulsion satellite in orbit at home and abroad can be used for carrying out east-west and north-south combined position keeping control by using four electric thrusters or can be used for carrying out north-south position keeping control by using two electric thrusters, and if the above propulsion mode is directly applied to the simply-configured electric propulsion satellite with the layout of two mechanical arms and two thrusters, the following defects are achieved: the thruster is started more times, and the service life of the thruster and the actual constraint of a fuel consumption mechanical arm type vector adjusting mechanism are possible.

Therefore, a position maintaining thrust distribution method considering the starting times and the limitation of a vector adjusting mechanism for the electric propulsion satellite with a simple configuration needs to be designed, so that the service life of the electric propulsion satellite with the stationary orbit is prolonged, and the reliability is improved.

Disclosure of Invention

The technical problem of the invention is solved: the method and the system for distributing the position keeping thrust of the electric thruster overcome the defects of the prior art, calculate the starting time and the speed increment of the electric thruster by adopting a complete analysis method, fully consider the practical engineering constraints and meet the position keeping task requirement of a stationary orbit satellite.

In order to solve the technical problem, the invention discloses a thrust distribution method for maintaining the position of an electric thruster, which comprises the following steps:

determining normal pointing gears of the two electric thrusters according to the position holding drift rate control quantity;

respectively calculating to obtain a target thrust direction [ X ] of the first electric thruster according to the determined normal pointing gears of the two electric thrusters_n,Y_n,Z_n]And a boot time period Δ t_nAnd a target thrust direction [ X ] of the second electric thruster_s,Y_s,Z_s]And a boot time period Δ t_s；

According to [ X ]_n,Y_n,Z_n]And [ X ]_s,Y_s,Z_s]And calculating to obtain the rotating speed omega of the first theoretical vector adjusting mechanism_nAnd a second theoretical vector adjusting mechanism rotating speed omega_s；

Will calculate the obtained [ X_n,Y_n,Z_n]And Δ t_nDistributing the calculated [ X ] to the first electric thruster_s,Y_s,Z_s]And Δ t_sDistributing the calculated omega to a second electric thruster_nAssigning the calculated ω to the first vector adjustment mechanism_sIs assigned to the second vector adjustment mechanism.

In the above method for distributing position-maintaining thrust of an electric thruster, determining normal directional shift positions of two electric thrusters according to a position-maintaining drift rate control amount includes:

determining a unit vector [ X, Y, Z ] of a thrust direction under a track coordinate system; the origin of the orbit coordinate system is the center of mass of the satellite, the X axis points to the advancing direction of the satellite, the Z axis points to the ground, and the Y axis, the X axis and the Z axis meet the right-hand rule;

calculating to obtain the adjusting range C of the vector adjusting mechanism_y＝Y/Z；

For the regulation range C_yN are equally divided to obtain n normal direction gears C which are arranged from small to large_ys：C_ys＝C_y1、C_y2、…、C_yn(ii) a Wherein each normal direction is towards gear C_y1、C_y2、…、C_ynThe corresponding allowable ranges of the drift rate are as follows: [ Delta DL₁,ΔDH₁]、[ΔDL₂,ΔDH₂]、…、[ΔDL_n,ΔDH_n]；

Acquiring a position holding drift rate control quantity delta D;

if Δ D ∈ [ Δ DL ]₁,ΔDH₁]Then, the normal direction gear of the two electric thrusters is determined to be C_ys＝C_y1；

If Δ D ∈ [ Δ DL ]₂,ΔDH₂]Then, the normal direction gear of the two electric thrusters is determined to be C_ys＝C_y2；

And so on;

if Δ D ∈ [ Δ DL ]_n,ΔDH_n]Then, the normal direction gear of the two electric thrusters is determined to be C_ys＝C_yn。

In the method for distributing the position maintaining thrust of the electric thrusters, the target thrust direction [ X ] of the first electric thruster is respectively calculated according to the determined normal directional gears of the two electric thrusters_n,Y_n,Z_n]And a boot time period Δ t_nAnd a target thrust direction [ X ] of the second electric thruster_s,Y_s,Z_s]And a boot time period Δ t_sThe method comprises the following steps:

acquiring eccentricity control vectors delta e in the x direction and the y direction under a track coordinate system_xAnd Δ e_yAnd tilt control vectors Δ i in the x-and y-directions_xAnd Δ i_y；

According to Δ e_x、Δe_y、Δi_xAnd Δ i_yCalculating to obtain the first electric pushVelocity delta VN in the direction of force multiplier x_xAnd a speed increment VS in the x-direction of the second electric thruster_xAnd the radial distribution identification flagV of the two electric thrusters_zAnd the radial distribution difference V_z0；

According to flagV_zAnd V_z0And calculating to obtain a speed increment VN of the first electric thruster in the y direction_yAnd velocity increment VN in the z-direction_zAnd a speed increment VS in the y-direction of the second electric thruster_yAnd z-direction velocity increment VS_z；

According to VN_y、VN_z、VS_yAnd VS_zAnd calculating to obtain a target thrust direction [ X ] of the first electric thruster_n,Y_n,Z_n]And a boot time period Δ t_nAnd a target thrust direction [ X ] of the second electric thruster_s,Y_s,Z_s]And a boot time period Δ t_s。

In the above-described electric thruster position maintaining thrust force distributing method, VN_xAnd VS_xThe calculation flow of (2) is as follows:

according to the nominal orbital velocity V of the geostationary orbit_sAnd the earth static orbit nominal orbit angular velocity omega_eAnd calculating to obtain a constant A, a constant B and an intermediate parameter aa:

then there are:

speed increment VN of first electric thruster in x direction_xComprises the following steps:

speed increment VS of second electric thruster in x direction_xComprises the following steps:

in the above-described electric thruster position holding thrust force distribution method, the flagV_zAnd V_z0The calculation flow of (2) is as follows:

calculating to obtain an intermediate variable dV_ztemp：

According to dV_ztempDetermining flagV_z：

If dV_ztempIf the value is less than or equal to 0, flagV_z＝1

If dV_ztempIf > 0, flagV_z＝-1

Calculating to obtain a radial distribution difference value V_z0：

Wherein, dV_zIndicating the difference, dV, between the radial control quantities of the two electric thrusters_z＝abs(dV_ztemp)，V_y0And the normal control quantity of the unilateral electric thruster is shown.

In the above-described electric thruster position maintaining thrust force distributing method, VN_y、VN_z、VS_yAnd VS_zThe calculation flow of (2) is as follows:

calculating to obtain an intermediate variable V_ytemp：

When flagV is present_zWhen 1, there are:

VN_y＝V_ytemp

VN_z＝V_z0+dV_z

VS_y＝V_y0-V_ytemp

VS_z＝V_z0

when flagV is present_zWhen-1, there is:

VN_y＝V_y0-V_ytemp

VN_z＝V_z0

VS_y＝V_ytemp

VS_z＝V_z0+dV_z。

in the above-described electric thruster position holding thrust force distribution method, [ X [ X ] ]_n,Y_n,Z_n]、Δt_n、[X_s,Y_s,Z_s]And Δ t_sThe calculation flow of (2) is as follows:

according to VN_x、VN_yAnd VN_zCalculating to obtain [ X ]_n,Y_n,Z_n]And Δ t_n：

According to VS_x、VS_yAnd VS_zCalculating to obtain [ X ]_s,Y_s,Z_s]And Δ t_s：

WhereinF represents the magnitude of the thrust of the electric thruster, V_eRepresenting the electrical thruster specific impulse, mass representing the satellite mass.

In the above-described electric thruster position holding thrust force distribution method, the thrust force is distributed in accordance with [ X ]_n,Y_n,Z_n]And [ X ]_s,Y_s,Z_s]And calculating to obtain the rotating speed omega of the first theoretical vector adjusting mechanism_nAnd a second theoretical vector adjusting mechanism rotating speed omega_sThe method comprises the following steps:

determining a current heading [ X ] of a first electric thruster_n0,Y_n0,Z_n0]And calculating to obtain [ X ]_n,Y_n,Z_n]And [ X ]_n0,Y_n0,Z_n0]Angle theta therebetween_n；

Determining a current heading [ X ] of a second electric thruster_s0,Y_s0,Z_s0]And calculating to obtain [ X ]_s,Y_s,Z_s]And [ X ]_s0,Y_s0,Z_s0]Angle theta therebetween_s；

Obtaining the rotating speed omega of the maximum theoretical vector adjusting mechanism_max；

When theta is_n≥θ_sIn time, there are:

ω_n＝ω_max

when theta is_n＜θ_sIn time, there are:

ω_s＝ω_max。

in the method for distributing the thrust for maintaining the position of the electric thruster, a first vector adjusting mechanism is arranged on the south side of a satellite and connected with the first electric thruster for realizing the adjustment of the thrust direction in the x direction, the y direction and the z direction; the second vector adjusting mechanism is arranged on the north side of the satellite and connected with the second electric thruster, and is used for adjusting thrust direction in the x direction, the y direction and the z direction.

Correspondingly, the invention also discloses a position maintaining thrust distribution system of the electric thruster, which comprises:

the gear determining module is used for determining normal pointing gears of the two electric thrusters according to the position holding drift rate control quantity;

a first calculation module, configured to calculate, according to the determined normal pointing gears of the two electric thrusters, a target thrust direction [ X ] of the first electric thruster_n,Y_n,Z_n]And a boot time period Δ t_nAnd a target thrust direction [ X ] of the second electric thruster_s,Y_s,Z_s]And a boot time period Δ t_s；

A second calculation module for calculating according to [ X_n,Y_n,Z_n]And [ X ]_s,Y_s,Z_s]And calculating to obtain the rotating speed omega of the first theoretical vector adjusting mechanism_nAnd a second theoretical vector adjusting mechanism rotating speed omega_s；

An allocation module for allocating the calculated [ X_n,Y_n,Z_n]And Δ t_nDistributing the calculated [ X ] to the first electric thruster_s,Y_s,Z_s]And Δ t_sDistributing the calculated omega to a second electric thruster_nAssigning the calculated ω to the first vector adjustment mechanism_sIs assigned to the second vector adjustment mechanism.

The invention has the following advantages:

(1) the invention discloses a thrust distribution scheme for maintaining the position of an electric thruster, wherein each position protection control cycle of a south electric thruster and a north electric thruster is respectively started once, the starting time is short, and the service life of the electric thruster is prolonged.

(2) The invention discloses a thrust allocation scheme for maintaining the position of an electric thruster, which has less calculation amount and reduces the on-satellite calculation resource requirement.

(3) The invention discloses a thrust distribution scheme for maintaining the position of an electric thruster, which considers the moving range and the rotating speed bearing capacity of a vector adjusting mechanism and is safer and more reliable.

Drawings

FIG. 1 is a flow chart illustrating the steps of a method for distributing position maintaining thrust of an electric thruster in accordance with an embodiment of the present invention;

FIG. 2 is a schematic diagram of a layout of an electric propulsion satellite thruster according to an embodiment of the present invention;

FIG. 3 is a graph of a simulation example-geographical latitude and longitude curves in an embodiment of the present invention;

fig. 4 is a block diagram of a position maintaining thrust force distribution system of an electric thruster in an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The invention discloses a method for distributing position keeping thrust of an electric thruster, which is a simply configured method for distributing position keeping thrust of an electric propulsion satellite. Firstly, selecting a proper normal direction of the electric thruster according to the requirement of the position keeping drift rate control quantity; then, acquiring three-dimensional directions and starting-up time lengths of the two electric thrusters corresponding to the determined normal directions; and finally, distributing the theoretical rotating speeds of the two vector adjusting mechanisms according to the thrust distribution mode of the two electric thrusters. The invention adopts a complete analysis mode, solves the problem of the position maintaining control distribution of the electric thruster under the layout of the double mechanical arms and the electric thruster, reduces the fuel consumption and reduces the influence of the motion of the vector adjusting mechanism on the satellite.

As shown in fig. 1, in the present embodiment, the method for distributing position maintaining thrust of an electric thruster includes:

and step 101, determining normal pointing gears of the two electric thrusters according to the position holding drift rate control quantity.

In the present embodiment, the electric thruster position maintaining thrust force distribution method can be applied to, but is not limited to, a simple configuration of an electric propulsion satellite. As shown in fig. 2, the layout of the simple configuration electric propulsion satellite is as follows: two electric thrusters and two vector adjusting mechanisms. The first vector adjusting mechanism is arranged on the south side of the satellite, is connected with a first electric thruster and is used for realizing adjustment of thrust direction in the x direction, the y direction and the z direction; the second vector adjusting mechanism is arranged on the north side of the satellite and connected with the second electric thruster, and is used for adjusting thrust direction in the x direction, the y direction and the z direction. Namely, the first vector adjusting mechanism and the second vector adjusting mechanism are respectively and obliquely arranged on the north and south sides of the satellite back floor and are respectively used for realizing the adjustment of the three-dimensional direction of the first electric thruster and the second electric thruster. The method for distributing the position maintaining thrust of the electric thruster can be executed in one orbit control period, and ignition is successively carried out in the one position maintaining control period, so that the satellite can jointly adjust six orbits.

Preferably, a position hold drift rate control quantity, denoted as Δ D, may be determined. Wherein:

if Δ D ∈ [ Δ DL ]₁,ΔDH₁]Then, the normal direction gear of the two electric thrusters is determined to be C_ys＝C_y1；

If Δ D ∈ [ Δ DL ]₂,ΔDH₂]Then, the normal direction gear of the two electric thrusters is determined to be C_ys＝C_y2；

And so on;

if Δ D ∈ [ Δ DL ]_n,ΔDH_n]Then, the normal direction gear of the two electric thrusters is determined to be C_ys＝C_yn。

Further, the allowable range of the drift rate corresponding to each normal directional gear is determined as follows: determining unit vectors [ X, Y, Z ] of thrust directions under a orbital coordinate system](ii) a Calculating to obtain the adjusting range C of the vector adjusting mechanism_yY/Z; for the regulation range C_yN are equally divided to obtain n normal direction gears C which are arranged from small to large_ys：C_ys＝C_y1、C_y2、…、C_yn(ii) a Each normal direction gear C_y1、C_y2、…、C_ynThe corresponding allowable ranges of the drift rate are as follows: [ Delta DL₁,ΔDH₁]、[ΔDL₂,ΔDH₂]、…、[ΔDL_n,ΔDH_n]. Wherein, the railThe origin of the orbit coordinate system is the center of mass of the satellite, the X axis points to the advancing direction of the satellite, the Z axis points to the ground, and the Y axis, the X axis and the Z axis meet the right-hand rule.

102, respectively calculating to obtain a target thrust direction [ X ] of the first electric thruster according to the determined normal pointing gears of the two electric thrusters_n,Y_n,Z_n]And a boot time period Δ t_nAnd a target thrust direction [ X ] of the second electric thruster_s,Y_s,Z_s]And a boot time period Δ t_s。

In this embodiment, the step 102 may specifically include the following sub-steps:

substep 1021, obtaining eccentricity control vector delta e in x direction and y direction of track coordinate system_xAnd Δ e_yAnd tilt control vectors Δ i in the x-and y-directions_xAnd Δ i_y。

Substep 1022, based on Δ e_x、Δe_y、Δi_xAnd Δ i_yAnd calculating to obtain a speed increment VN of the first electric thruster in the x direction_xAnd a speed increment VS in the x-direction of the second electric thruster_xAnd the radial distribution identification flagV of the two electric thrusters_zAnd the radial distribution difference V_z0。

In the present exemplary embodiment, the speed increment VN in the x direction of the first electric thruster_xAnd a speed increment VS in the x-direction of the second electric thruster_xThe solving formulas of (1) are respectively as follows:

preferably, the nominal orbital velocity V can be determined according to the earth's stationary orbit_sAnd the earth static orbit nominal orbit angular velocity omega_eAnd calculating to obtain a constant A, a constant B and an intermediate parameter aa:

further, the flag V is allocated radially_zAnd the radial distribution difference V_z0The solution flow of (a) may be as follows:

first, an intermediate variable dV is calculated_ztemp：

Then, according to the intermediate variable dV_ztempDetermining flagV_z：

If dV_ztempIf the value is less than or equal to 0, flagV_z＝1

If dV_ztempIf > 0, flagV_z＝-1

Finally, calculating to obtain a radial distribution difference value V_z0：

Wherein, dV_zIndicating the difference, dV, between the radial control quantities of the two electric thrusters_z＝abs(dV_ztemp)，V_y0And the normal control quantity of the unilateral electric thruster is shown.

Substep 1023, based on flagV_zAnd V_z0And calculating to obtain a speed increment VN of the first electric thruster in the y direction_yAnd velocity increment VN in the z-direction_zAnd a speed increment VS in the y-direction of the second electric thruster_yAnd z-direction velocity increment VS_z。

In this embodiment, when flagV_zWhen 1, there are: VN_y＝V_ytemp、VN_z＝V_z0+dV_z、VS_y＝V_y0-V_ytemp、VS_z＝V_z0(ii) a When flagV is present_zWhen-1, there is: VN_y＝V_y0-V_ytemp、VN_z＝V_z0、VS_y＝V_ytemp、VS_z＝V_z0+dV_z。

Preferably, for the intermediate variable V_ytempThe method comprises the following steps:

substep 1024, based on VN_y、VN_z、VS_yAnd VS_zAnd calculating to obtain a target thrust direction [ X ] of the first electric thruster_n,Y_n,Z_n]And a boot time period Δ t_nAnd a target thrust direction [ X ] of the second electric thruster_s,Y_s,Z_s]And a boot time period Δ t_s。

In this embodiment, VN may be first determined_x、VN_yAnd VN_zCalculating to obtain [ X ]_n,Y_n,Z_n]And Δ t_n：

Then according to VS_x、VS_yAnd VS_zCalculating to obtain [ X ]_s,Y_s,Z_s]And Δ t_s：

Wherein F represents the thrust magnitude of the electric thruster, V_eThe specific impulse of the electric thruster is shown,mass represents satellite quality.

Step 103, according to [ X ]_n,Y_n,Z_n]And [ X ]_s,Y_s,Z_s]And calculating to obtain the rotating speed omega of the first theoretical vector adjusting mechanism_nAnd a second theoretical vector adjusting mechanism rotating speed omega_s。

In this embodiment, the current orientation [ X ] of the first electric thruster may be determined first_n0,Y_n0,Z_n0]And current orientation [ X ] of second electric thruster_s0,Y_s0,Z_s0](ii) a And calculating to obtain [ X_n,Y_n,Z_n]And [ X ]_n0,Y_n0,Z_n0]Angle theta therebetween_n，[X_s,Y_s,Z_s]And [ X ]_s0,Y_s0,Z_s0]Angle theta therebetween_s。

Then, the maximum theoretical vector adjusting mechanism rotating speed is obtained and recorded as omega_max。

When theta is_n≥θ_sIn time, there are:

ω_n＝ω_max

when theta is_n＜θ_sIn time, there are:

ω_s＝ω_max

step 104, calculating the obtained [ X ]_n,Y_n,Z_n]And Δ t_nDistributing the calculated [ X ] to the first electric thruster_s,Y_s,Z_s]And Δ t_sDistributing the calculated omega to a second electric thruster_nAssigning the calculated ω to the first vector adjustment mechanism_sIs assigned to the second vector adjustment mechanism.

In conclusion, the method adopts a complete analysis method to calculate the starting time length and the speed increment of the electric thruster, fully considers the actual engineering constraint and can meet the requirement of the position maintenance task of the geostationary orbit satellite.

On the basis of the above embodiments, the following description will be made in conjunction with several specific examples.

For example, the thrust of a single electric thruster is 100mN, the mass of a satellite is 1380kg, and the fixed point longitude is 114E of east longitude; the position of the satellite keeps the control cycle to be 1 day; Δ D ═ 0.0043 °/day, Δ e_x＝0，Δe_y＝-2.29e-5/day，Δi_x＝0，Δi_y＝-0.0029°/day；C_y0.7. Then, a suitable normal pointing gear C can be selected_ys＝[1.7,1.0,0.7]The corresponding allowable ranges of the drift rate are as follows: [ -0.001,0.001]、[-0.003,0.003]、[-0.010,0.010]。

Based on the above known quantities in combination with the above steps, one can calculate: VN_z＝-0.237，VS_x＝0.011，dV_ztemp＝-0.0014，dV_z＝abs(dV_ztemp)＝0.0014，flagV_z＝1，V_ytemp＝0.079，V_z0＝0.112。

Further, there are: VN_z＝0.114，VN_y＝0.079，VS_z＝0.112，VS_y＝0.078。

Then the process of the first step is carried out,

finally, according to the current direction, omega can be calculated_n＝1°/s，ω_s＝0.54°/s。

Further, based on the above conditions: the thrust of a single electric thruster is 100mN, the mass of a satellite is 1380kg, and the fixed point longitude is 114 degrees E of east longitude; the position holding control period of the satellite is 1 day. The simulation duration is taken as 1 year. Then the simulation result as shown in fig. 3 can be obtained, and the thruster allocation method provided by the invention can keep the satellite within the 'dead zone' range of the fixed point longitude and latitude ± 0.5 °. Through simulation verification, the method can realize position keeping control electric thruster distribution under the simple configuration electric propulsion layout, and can be used for geosynchronous orbit position keeping control.

In conclusion, the thrust distribution method for maintaining the position of the electric thruster can distribute the thrust according to the accessibility of the vector adjusting mechanism and the rotation speed constraint, and realize the position maintaining control of the geosynchronous orbit.

On the basis of the above embodiment, as shown in fig. 4, the present invention also discloses an electric thruster position maintaining thrust distribution system, including: and a gear determining module 401, configured to determine normal pointing gears of the two electric thrusters according to the position holding drift rate control amount. A first calculating module 402, configured to respectively calculate, according to the determined normal directional gears of the two electric thrusters, a target thrust direction [ X ] of the first electric thruster_n,Y_n,Z_n]And a boot time period Δ t_nAnd a target thrust direction [ X ] of the second electric thruster_s,Y_s,Z_s]And a boot time period Δ t_s. A second calculation module 403 for calculating according to [ X_n,Y_n,Z_n]And [ X ]_s,Y_s,Z_s]And calculating to obtain the rotating speed omega of the first theoretical vector adjusting mechanism_nAnd a second theoretical vector adjusting mechanism rotating speed omega_s. An assignment module 404 for assigning the calculated [ X ]_n,Y_n,Z_n]And Δ t_nDistributing the calculated [ X ] to the first electric thruster_s,Y_s,Z_s]And Δ t_sAssigned to a second electric thrusterWill calculate the resulting ω_nAssigning the calculated ω to the first vector adjustment mechanism_sIs assigned to the second vector adjustment mechanism.

For the system embodiment, since it corresponds to the method embodiment, the description is relatively simple, and for the relevant points, refer to the description of the method embodiment section.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications of the present invention without departing from the spirit and scope of the present invention by using the methods and technical contents disclosed above.

Those skilled in the art will appreciate that the invention may be practiced without these specific details.