RU2282568C1 - Method of forming program for orientation of cryogenic stage at terminal control of injection into preset orbit - Google Patents

Abstract

FIELD: terminal control of motion trajectory of cryogenic stages injecting spacecraft into preset orbits by means of cruise engines.

SUBSTANCE: swivel combustion chamber of cruise engine is used for angular orientation and stabilization of cryogenic stage of spacecraft. Proposed method includes predicting parameters of motion of cryogenic stage at moment of cut-off of cruise engine; deviation of radius and radial velocity from preset magnitudes are determined; angle of pitch and rate of pitch are corrected and program of orientation of thrust vector for subsequent interval of terminal control is determined. By projections of measured phantom accelerations, angle of actual orientation of cruise engine thrust vector and misalignment between actual and programmed thrust orientation angles are determined. This misalignment is subjected to non-linear filtration, non-linear conversion and integration. Program of orientation of cryogenic stage is determined as difference between programmed thrust orientation angle and signal received after integration. Proposed method provides for compensation for action of deviation of cruise engine thrust vector relative to longitudinal axis of cryogenic stage on motion trajectory.

EFFECT: enhanced accuracy of forming preset orbit.

5 dwg, 1 tbl

Description

The present invention relates to the field associated with the guidance of spacecraft in a given orbit, which provides the specified parameters of their motion at the end of the maneuver.

The closest technical solution is a method for generating an orientation program for the upper stage (RB) in longitudinal control when performing an active maneuver [1], which consists in the fact that during the implementation of this maneuver, the motion parameters of the upper stage are predicted periodically with the terminal control T _y at the time of cutoff marching engine (MD), they determine the predicted deviations in radius, radial speed from their values in a given orbit and corrections to the parameters of orientation programs in tan azhu, providing performance terminal conditions, and is formed on the basis of their accelerating elaborated program block orientation θ pitch _etc. for the next control interval terminal in the form:

where ϑ _pr - the pitch angle of the booster block;

ϑ ₀ is the initial value of the program angle;

- скорость изменения программного угла;

- rate of change of the program angle;

t is the time counted from the moment the forecast was completed.

задаются в полетном задании.To start control, the parameter values параметров ₀ ,

are set in the flight task.

маршевого двигателя направлен по продольной оси разгонного блока. Отклонение вектора тяги

маршевого двигателя от продольной оси на угол Δϑ_р приводит к ошибке реализации заданного траекторного движения.The disadvantage of this method is the assumption that the thrust vector

the main engine is directed along the longitudinal axis of the booster block. Thrust vector deviation

the main engine from the longitudinal axis at an angle Δϑ _p leads to an error in the implementation of a given trajectory movement.

When marching engines are used in accelerating blocks for angular stabilization, the creation of control moments with their help relative to the center of mass is performed by deflecting the combustion chamber of the marching engine relative to the longitudinal axis. In this case, the average (balancing) component of the deflection of the combustion engine of the main engine, characterized by the angle Δϑ _d , has the greatest impact on the accuracy of the trajectory movement. The value of the balancing deviation of the sustainer’s combustion chamber depends on the displacement of the center of mass of the accelerating block relative to its longitudinal axis, deformation of the suspension frame of the sustainer engine, installation errors of the axis of the combustion chamber, and other reasons.

The technical result of the invention is to compensate for the influence of the deviation of the thrust vector of the marching engine relative to the longitudinal axis on the accuracy of the implementation of a given trajectory movement and thereby increase the accuracy of formation of a given orbit.

The specified technical result is achieved by the fact that in the known method of forming the orientation program of the upper stage during terminal control, pointing it into a given orbit, which consists in the fact that at the current pitch pitch angle and rate of change at each terminal control cycle, the upper stage motion parameters are predicted the cutoff moment of the main engine, they determine the deviations of the radius and radial velocity from their values in a given orbit, form correction signals p angle and angular pitch velocity, adjust the pitch angle and angular velocity, determine the thrust vector orientation program for the next terminal control interval, additionally determine the orientation of the marching engine thrust vector from the projections of the measured apparent accelerations on the axis of the coordinate system adopted for reading the pitch program angle this coordinate system and its deviation from the value of the program angle of orientation of the thrust vector, perform non-linear filtering of this deviation and subsequent non-linear linear transformation of the filtered signal, integrates the converted signal, limiting it to a predetermined level, and determining the program booster orientation by subtracting this signal from the program limited orientation of the thrust vector propulsion engine.

маршевого двигателя относительно продольной оси, и с этой целью программа ориентации разгонного блока, определяемая углом

, должна задаваться в виде:Thus, the specified technical result is achieved by the fact that the upper stage is deflected by an additional angle Δϑ _d along the pitch opposite to the deviation of the thrust vector

main engine relative to the longitudinal axis, and for this purpose, the orientation program of the upper stage, determined by the angle

must be specified as:

providing the estimated direction of traction, determined by the angle ϑ _CR

- скорректированный программный угол тангажа разгонного блока;Where

- adjusted pitch angle of the booster block;

ϑ _pr - the pitch angle of the booster block;

Δϑ _d - the angle of the marching engine.

Figure 1 presents the structural diagram of the block forming the orientation program of the upper stage in a known manner, which determines the desired direction of the thrust vector of the sustainer engine; figure 2 is a block diagram of the circuit forming the orientation program of the upper stage according to the proposed method; figure 3 shows the angles of orientation of the thrust vector ϑ _p , program orientation of the thrust vector ϑ _pr and the deviation of the direction of the thrust vector Δϑ _p from its program orientation; figure 4 presents the structure of blocks of non-linear orientation, non-linear transformation and the formation of a compensating correction; figure 5 shows the change in the orientation programs of the upper stage during its guidance in a given orbit according to the known and proposed methods for different values of the angles of deviation of the thrust vector in the balancing.

The block diagram of the block for the formation of the orientation program for the upper stage, which implements the known method, is shown in Fig. 1, where 1 is a block for predicting deviations (BPO) from a given orbit and calculating sensitivity functions, 2 is a block of corrective corrections (BPC) of program control, 3 is a block correction (BC) parameters of the orientation program.

непрерывно определяется текущее значение ϑ_пр. На каждом i-м такте терминального управления для прогнозируемого момента отключения маршевого двигателя вычисляются отклонения от заданной орбиты по радиус-вектору ΔR, по радиальной скорости ΔV и функции чувствительности L, J, S, Q вычисляемых отклонений к изменению параметров программы ориентации - угла тангажа и скорости его изменения.In block 1 (BPO) according to the known parameters of the orientation program ϑ ₀ and

the current value ϑ _{pr is} continuously determined At each i-th terminal control cycle, for the predicted moment of marching engine off, the deviations from the given orbit are calculated by the radius vector ΔR, by the radial velocity ΔV and the sensitivity functions L, J, S, Q of the calculated deviations to change the orientation program parameters - pitch angle and rate of change.

к параметрам программы ориентации, а в блоке 3 (БК) определяются скорректированные параметры программы ориентации на очередном такте терминального управления.Based on these data, in block 2 (BKP), the correction corrections Δϑ _0i are calculated,

to the parameters of the orientation program, and in block 3 (BC), the adjusted parameters of the orientation program are determined at the next terminal control cycle.

The block diagram of the formation circuit of the acceleration block orientation program according to the proposed method is shown in FIG. 2, where 4 is the orientation program formation block (BFP) by the known method, 5 is the apparent acceleration measurement unit (BICU), 6 is the deviation formation block (BFO) thrust vector relative to the longitudinal axis, 7 — block of nonlinear filtration (BNF), 8 — block of nonlinear transformation (BNP), 9 — block of the formation of a compensating correction (BFC), 10 — block of the formation of an orientation program (BFPO) by the proposed method.

In block 4 (BFP) by a known method, a thrust vector orientation program ϑ _{pr of the} form (1) is formed.

,

на оси системы координат O_g X_g Y_g, используемой для отсчета программного и текущего углов тангажа (фиг.3).From block 5 (BIKU), the projection values of the measured apparent accelerations of the upper stage are received

,

on the axis of the coordinate system O _g X _g Y _g used to read the program and current pitch angles (figure 3).

In block 6 (BFO), the mismatch between the direction of the thrust vector and the program orientation ϑ _pr , determined by the angle Δϑ _p , is calculated. For this, the current orientation of the thrust vector is determined - the angle ϑ _p :

The angle ϑ _p can be represented as:

ϑ _p = ϑ _pr + Δϑ _p

and therefore

sinϑ _p = sinϑ _pr · cosΔϑ _p + cosϑ _pr · sinΔϑ _p .

Given the small values of the angle of mismatch Δϑ _p , its value is determined from the last equation by the formula:

The error signal passes through a chain of consecutive blocks 7, 8, 9, the structure of which is shown in Fig.4. The transfer function of block 7 (BNF) has the form:

постоянная времени фильтра;Where

filter time constant;

To _f - gain linear portion of the characteristic.

и коэффициентом К_ф.The maximum rate of change of the output signal Δϑ _f block 7 (BNF) is determined by the magnitude of the restriction

and coefficient K _f .

Block 7 (BNF) excludes the passage of high-frequency components of the signal Δϑ _p to the input of block 8 (BNP).

, зоны нечувствительности Δ_зн и имеющие коэффициент усиления К_н на линейном участке характеристики. Сигнал

на выходе блока 8 (БНП) формируется по зависимости:Block 8 (BNP) is a nonlinear link, consisting of limiting the output signal at the level

dead zones Δ _zn and having a gain of K _n in the linear portion of the characteristic. Signal

at the output of block 8 (BNP) is formed according to:

In block 9 (BFKP), the signal Δϑ _n is integrated and the output signal Δϑ _{d is} limited to ± Δϑ _d :

формируется в блоке 10 (БФПО), на первый вход которого из блока 4 (БФП) поступает сигнал программы ориентации вектора тяги ϑ_пр, а на второй - сигнал Δϑ_д из блока 9 (БФКП):Orientation program

is formed in block 10 (BFPO), the first input of which from block 4 (BFP) receives the signal of the thrust vector orientation program ϑ _pr , and the second input receives the signal Δϑ _d from block 9 (BFKP):

The angle Δϑ _d changes until the orientation of the thrust vector ϑ _p becomes equal to the generated program orientation angle ϑ _pr In this case, Δϑ _p = 0 and the signal Δϑ _n = 0 is received at the input of block 9 (BFKP), which indicates that the angle Δϑ _{d has} reached a value equal to the balancing deviation of the main engine chamber.

To evaluate the effectiveness of the proposed method of forming the RB orientation program taking into account the compensation of the thrust vector deviation of the marching engine, a comparative simulation of launching the upper stage into the target circular orbit with a height of N _cr = 212244 m using this method and prototype is carried out.

The values of the heights of apogee H _a and perigee H _p for different values of the angles of the balancing deviation of the combustion chamber of the marching engine δ _md required to parry the corresponding disturbing moments are given in the table for two control methods. The deviations of the apogee heights ΔН _а and perigee ΔН _p relative to a given height Н _{cr of a} circular orbit are also given there.

Option Way δ _ppm [deg] N _a [m] N _p [m] ΔН _a [m] ΔN _p [m] one Prototype 0 212651 211837 407 -407 2 Prototype 5 222691 201767 10449 -10477 3 Proposed 5 212659 211826 415 -418

As can be seen from the above results, the application of the proposed method under conditions of a marching engine’s combustion chamber deviation of 5 degrees compensates for this disturbance and allows one to achieve accuracy of the formed orbit parameters, which the prototype method provides, provided that the direction of the thrust vector coincides with the longitudinal axis of the accelerating block.

К_ф=0,15 1/с,

Δ_зн=0,16 град,

К_н=0,15.When modeling, the parameter values in the blocks in Fig. 4 were used:

K _f = 0.15 1 / s,

Δ _zn = 0.16 degrees

K _n = 0.15.

Figure 5 presents the processes of formation of orientation programs in the process of pointing to a given orbit and the numbers 1 ÷ 4 indicate the following parameters:

1, 2 - program orientation angle ϑ _ol for options 1 and 2 of the table,

для варианта 3 таблицы,3 - program orientation angle

for option 3 of the table,

4 - change in the angle Δϑ _d in option 3.

Information sources.

1. A.Syrov, V.N. Sokolov, V.V. Ezhov, L.I. Kislik "Algorithm for guidance of the upper stage with uncontrolled marching engine and low thrust-weight ratio". Aerospace Engineering and Technology, No. 1, 1998

Claims (1)

A method for generating a program for accelerating block orientation during terminal control pointing it to a given orbit, which consists in predicting the motion parameters of the upper stage at the moment the main engine is cut off at the current pitch pitch angle and rate of change at each tact of the terminal control, and determining deviations from them radius and radial velocity from their values in a given orbit, form correction signals for the angle and angular velocity of the pitch, adjust the values of the angle and angle the pitch velocity, determine the thrust vector orientation program for the next terminal control interval, characterized in that the projection of the marching engine thrust vector in this coordinate system and its deviation from the projected measured apparent accelerations on the axis of the coordinate system adopted for counting the pitch program angle the values of the programmed orientation angle of the thrust vector perform nonlinear filtering of this deviation and the subsequent nonlinear transformation of the filtered signal, integrate They transform the converted signal, limit it at a given level, and determine the orientation program of the upper stage by subtracting this limited signal from the orientation program of the thrust vector of the main engine.

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