RU2432596C1 - Method of controlling movement of upper-stage rocket at end of manoeuvre - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: problem of correcting the direction of the thrust vector is solved by determining and adjusting pitch and course angle values required to compensate for deviation of radial and orthogonal velocities from their required values on the formed orbit the moment the cruise engine is shutdown.

EFFECT: high procedural accuracy of forming given orbit by correcting the direction of the thrust vector of the cruise engine at the end of manoeuvre after switching to standby mode of the cruise engine shutdown performed after a given period of time before its predicted shutdown time.

2 dwg, 1 tbl

Description

The present invention relates to the field associated with the control of the motion of the upper stage (RB) when placing it in a given orbit.

The closest technical solution is the control method used in the RB control system, in which, before starting the maneuver, the RB is turned in pitch and course to achieve the orientation determined by the values of the initial angles of the pitch and course change programs specified in the flight task (PZ), and in this orientation, the longitudinal axis of the Republic of Belarus is stabilized until the start of working out a given orientation program, data from the control parameters and the orbit of the RB formed on the maneuver are read from the knowledge base at the time specified in the knowledge story and they turn on the pulse correction engines for preloading fuel in the tanks for the time interval specified in the PP, start the marching engine (MD), after a fixed point in time after starting the MD start working out the RB orientation program set in the PP, adjust the orientation program using terminal control to ensure the formation the orbits with the parameters specified in the PP, turn off the MD upon reaching the specified energy functional, and for the set time interval before that, fix the orientation program with parameters, p radiation after the last adjustment. For a certain point in time before the MD is turned off, the standby mode for its cut-off is switched on, in which the orientation program is frozen and the RB stabilizes relative to the fixed direction [1].

The basis of the terminal control is a periodically implemented forecast of the RB movement with the current orientation program in the form of time-linear changes in yaw angles (ψ) and pitch (ϑ), determined in the inertial coordinate system of the launch associated with the starting point of the maneuver:

ϑ = a + b

ψ = c + d

where a, c are the initial values of the pitch and course angles;

b, d are the angular velocity of the pitch and course angles.

At the predicted moment of MD shutdown, parameters are calculated that determine deviations from the generated orbit. In the longitudinal control channel, these include deviations along the radius ΔR and radial velocity ΔV, and in the lateral, deviations from the orbit plane ΔRb and its rate of change ΔVb. Based on these data, amendments are determined to the current program of orientation of the Republic of Belarus, providing compensation for the above deviations.

The errors in compensating deviations from a given orbit depend on the difference between the calculated and actual sensitivity functions of these deviations for changing the parameters of the orientation program, as well as on the dynamic characteristics of control and stabilization systems. In addition, with large initial deviations with a limited number of terminal control clock cycles, the process of working out the initial deviations may not be completed. In practice, there may be short maneuvers in which terminal control cannot be implemented. In these cases, a flight is performed according to a rigid, uncorrectable orientation program with the parameters specified in the PP. All these facts affect the accuracy of the formation of the orbits, that is, the methodological errors of control, and determine the disadvantage of the described method of controlling the RB.

The technical result of the invention is to increase the methodological accuracy of the formation of a given orbit by correcting the direction of the MD thrust vector at the end of the maneuver after switching to the MD cut-off standby mode, performed for a set time interval T _oz to the predicted moment of turning it off. At this stage of the flight, the task of correcting the direction of the MD thrust vector is realized by determining and working out the values of the pitch angles and heading required to compensate for the deviations ΔV and ΔVb at the time of the MD shutdown, since the error in the formation of the orbit is determined primarily by the speed deviations.

To solve this problem, the Greenwich geocentric inertial coordinate system (GISC), inertial inference coordinate system (HSCI) and orbital coordinate system (USC) are used.

The specified technical result is achieved by the fact that in the known method of controlling the movement of the RB at the end of the maneuver, which consists in the fact that before starting the maneuver, the RB is rotated in pitch and course until the orientation determined in the PP by the initial angles of the orientation program on the maneuver is stabilized the direction of the longitudinal axis of the Republic of Belarus until the start of working out a given orientation program, turn on the pulse correction engines for the fuel compression in the tanks for the time interval specified in the PP, start MD, trigger I start a fixed time after starting the MD, start working out the RB orientation program, adjust the orientation program using terminal control, sequentially fix the orientation program at set intervals before turning off the MD, switch to the MD cut-off standby mode and turn off the MD when the specified energy functional is reached, additionally after the transition to the standby mode of the MD cut-off according to two successively measured values of the velocity vectors, the radius vector of the RB, and the apparent acceleration determine the current determining the values of the velocity deviations in the radial and orthogonal directions, calculate the remaining time interval until the specified energy functional is achieved and the required values of the radial and orthogonal accelerations for working out these speed deviations in this interval using the calculated values of the radial and orthogonal accelerations and the value of the measured apparent acceleration module, determine the value of the third transversal component of the required acceleration, recalculate the obtained acceleration components ISKV to compute them device in this system MD orientation thrust in pitch and rate provides compensation for deviations in the radial and orthogonal component of the velocity and deploying RB longitudinal axis in the direction of the calculated orientation.

Figure 1 shows the coordinate system GISK (OXYZ), OSK (OE ₁ EB), ISKV (OX _V Y _B Z _B ) and the position of the RB determined by the radius vector OR ₂ , figure 2 - graphs of the changes calculated ΔV, ΔVb and the required ΔV _Tr , ΔVb _Tr speed deviations RB in the longitudinal and lateral control channels.

The proposed method for controlling the motion of the upper stage at the end of the maneuver is implemented as follows.

, скорости

и радиуса

. Начало этой системы координат находится в центре Земли, ось ОХ находится в плоскости нулевого меридиана и направлена в точку его пересечения с экватором, ось OZ направлена на Северный полюс, а ось OY образует правую систему координат. Положение ГИСК замораживается в момент старта ракеты-носителя.In the GISC, the parameters of the motion of the RB are determined: the apparent acceleration vector

, speeds

and radius

. The origin of this coordinate system is in the center of the Earth, the OX axis is in the plane of the zero meridian and is directed to the point of its intersection with the equator, the OZ axis is directed to the North Pole, and the OY axis forms the right coordinate system. The position of the GISC is frozen at the time of launch of the launch vehicle.

The axis OY _{B of the} ISSCW is directed from the center of the Earth to the selected point of the calculated flight path of the RB, the axis ОX _{B is} perpendicular to the axis OY _B and directed in the calculated direction of motion, and the axis OZ _B complements the coordinate system to the right.

,

,

единичных ортов осей ИСКВ на оси ГИСК и задаются в ПЗ.The orientation of the HSCI relative to the GISC is determined by the transition matrix from the GISC to the HISC M _GI , the elements of which are projections

,

,

single unit vectors of the HSCW axes on the GISC axis and are specified in the PP.

,

,

, совпадающими по направлению с векторами Лапласа и кинетического момента заданной орбиты (фиг.1).The beginning of the GSC is located in the center of the Earth, and its orientation relative to the GISC is set in the PP by projections of single unit vectors

,

,

coinciding in direction with the Laplace vectors and the kinetic moment of a given orbit (figure 1).

In addition, the values of the focal parameter of the orbit Fp, its eccentricity Ex, and the given energy functional F _cs , upon reaching which the MD is turned off, are also used from the PP.

от работы МД, о радиус-векторе

и векторе абсолютной скорости

. Для каждого i-го момента (T₁, Т₂) вычисляют следующие параметры:After passing the command to enter the MD cutoff standby mode at two consecutive time points, the measurements T ₁ and T ₂ record the information in the GISC about the apparent acceleration vector

from the work of MD, about the radius vector

and absolute speed vector

. For each i-th moment (T ₁ , T ₂ ) the following parameters are calculated:

- module of the apparent acceleration vector W _i

;

;

- module of the absolute velocity vector V _i

;

;

- the module of the radius vector R _i

;

;

- functional energy F _i

F _i = V _i ² /2-B ₀ / R _i ,

where B ₀ is the gravitational constant equal to 3.9860044 · 10 ¹⁴ m ³ / s ² .

и

до отключения МД вычисляют по формуле:The remaining time interval T _ost from the moment T ₂ measurement of motion parameters

and

before shutdown, the MD is calculated by the formula:

,

,

- производная от функционала энергии FWhere

is the derivative of the energy functional F

.

.

The angular position of the RB in the OSK at time T ₂ is determined by the angle of the anomaly η (figure 1), and

Sinη = X _E1 / R2,

Cosη = -X _E / R2,

и

where X _E1 , X _E are the projections of the radius vector R ₂ on the direction of the vectors

and

X _E1 = R ₂ (1) · E ₁ (1) + R ₂ (2) · E ₁ (2) + R ₂ (3) · E ₁ (3),

X _E = R ₂ (1) E (1) + R ₂ (2) E (2) + R ₂ (3) E (3).

и

на момент Т₂ вычисляют значения скоростных отклонений ΔV, ΔVb:According to the parameters

and

at the time T ₂ calculate the values of the speed deviations ΔV, ΔVb:

ΔV = V _R2 -V _orb ,

ΔVb _i = V _i (1) · B (1) + V _i (2) · B (2) + V _i (3) · B (3),

- радиальная скорость на формируемой орбите [2];Where

- radial velocity in the formed orbit [2];

V _R2 = (R ₂ (1) · V ₂ (1) + R ₂ (2) · V ₂ (2) + R ₂ (3) · V ₂ (3)) / R ₂ is the calculated radial velocity.

Due to the short duration of the standby mode of cut-off (5 ÷ 10 seconds), it can be considered that the acceleration of RB Wi in this section is constant, that is, W = W ₂ .

To provide compensation for deviations ΔV, ΔVb for the remaining time interval T _ost before turning off the MD, their change must be performed with the required accelerations (figure 2):

,

,

.

.

определяется какThese accelerations determine the required values of the radial and orthogonal components of the acceleration W developed by the main engine. Transversal component

defined as

.

.

Three components of acceleration determine the required orientation of the thrust of the marching engine relative to the formed orbit. To implement this orientation, determine the appropriate values of the pitch angles and heading in the accepted for their reference HMIS.

,

,

определяют какProjections of required accelerations on vectors

,

,

determine how

,

,

.

.

в ОСК, причемThese projections define the vector

in USC, and

W _Tr (1) = W _E1 , W _Tr (2) = W _E , W _Tr (3) = W _B.

,

,

, имеет видTransition matrix M _VG from GISK to the coordinate system defined by vectors

,

,

has the form

The vector of required accelerations in the GISC is defined as

,

,

and in ISKV

.

.

определяют требуемые значения угла тангажа ϑ_тр и курса ψ_тр, реализующих направление вектора тяги, обеспечивающее компенсацию отклонений ΔV, ΔVb:From the elements of the matrix

determine the required values of the pitch angle ϑ _tr and the course ψ _tr , realizing the direction of the thrust vector, providing compensation for deviations ΔV, ΔVb:

,

,

.

.

The effectiveness of the correction of the direction of the thrust vector at the end of the maneuver was verified by mathematical modeling of the launch of the RB into the geostationary orbit under the conditions of maximum variation (MAX and MIN) according to the RB parameters: traction ratio, balancing angles of the position of the combustion chamber MD, efficiency of stabilization engines. In this case, the mismatch between the current and the required orientation was worked out with an angular velocity ω = 1 g / s for the duration of the standby time of the cut-off T _ozh equal to 5 and 10 seconds. The simulation results are shown in the table. The controlled parameters for the geostationary orbit are the orbital period T, the inclination angle i and the eccentricity Ex, the requirements for which are determined by the values: T = 89276 sec, i = 0, Ex = 0.

Table Mode Condition T _aw T I Ex sec sec hail - MAX No correction 5 89265 0.0774 0 With correction 5 89269 0.0495 0 With correction 10 89273 0.0075 0.000488 MIN No correction 5 89254 0.0411 0.000646 With correction 5 89261 0.0377 0.000598 With correction 10 89262 0.0027 0.000488

From the data obtained it follows that the correction of the direction of the MD thrust vector at the end of the maneuver improved the indicators for the period and inclination with an almost constant eccentricity. In this case, the error in the angle of inclination of the orbit during the duration of the standby mode of cutoff T _oz = 5 seconds decreased 1.1–1.5 times. With an increase in the cutoff standby time T _oz to 10 seconds, the error in the inclination angle decreased by an order of magnitude.

Information sources

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

2. Krafft Erike. Space flight. M .: State publishing house of physical and mathematical literature, 1963, v.1, p.398.

Claims (1)

The way to control the motion of the booster block at the end of the maneuver, which consists in the fact that before starting the maneuver, the booster block is rotated in pitch and course until the orientation determined in the flight task by the initial angles of the orientation program on the maneuver is stabilized, the longitudinal axis of the booster block is stabilized in this direction to the moment of the start of working out a given orientation program, turn on the pulse correction engines for preloading fuel in the tanks for the time interval specified in the flight task, start the mid-flight engine, after a fixed moment of time after the start of the mid-flight engine, they begin to work out the orientation program of the booster block, the orientation program is corrected using terminal control, the orientation program is sequentially fixed before the mid-flight engine is turned off, go into standby mode for the mid-flight engine cut-off and the main engine upon reaching a predetermined energy functional, characterized in that after switching to standby mode, cutoffs of marshes of the engine using two successively measured values of the velocity vectors, radius vector and apparent acceleration of the accelerating block, determine the current values of the speed deviations in the radial and orthogonal directions, calculate the remaining time interval until the specified energy functional is achieved, and the required values of the radial and orthogonal accelerations for working out these speed deviations in this interval using the calculated values of the radial and orthogonal accelerations and the value of the modulus of the measured of accelerating acceleration, determine the value of the third transversal component of the required acceleration, recalculate the obtained acceleration components into the inertial coordinate system of the derivation, calculate the orientation of the main engine thrust required in this system along the pitch and course angles, which compensates for deviations along the radial and orthogonal velocity components, and unfold the longitudinal axis of the booster block in the direction of the calculated orientation.

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