RU2625687C2 - Method of spacecraft inertial actuators kinematic momentum drop and device for the method realisation - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: group of inventions relates to controlling the spacecraft relative motion by its interaction with the geomagnetic field. In the method, the components of the kinematic momentum accumulated by the spacecraft inertial actuators and geomagnetic induction along the X, Y, Z axes are determined. According to these data, the signals of the unloading magnetic momentums along each X, Y, Z axis are formed. The device includes the sensors of the specified components of the kinematic moment and geomagnetic induction, connected to the control unit inputs and magnetic IO for the unloading magnetic momentums formation. Three digital-to-analog converters, three comparators, three "I" elements, three electronic switches, providing the formation by the magnetic IO of optimal along the X, Y, Z components of unloading momentums geomagnetic induction are also introduced.

EFFECT: reduction of power consumption and heat generation by the magnetic actuators.

2 cl, 2 dwg

Description

Appointment

The present invention relates to techniques for controlling the orientation of spacecraft (SC), in particular small SC, for unloading the kinetic moment of inertial actuators (flywheels of various types, power gyroscopes, etc.) of the orientation system and initial reassurance of the SC after separation from the rocket, by interactions with the geomagnetic field of the Earth.

State of the art

Currently, there is an increase in the creation of small spacecraft (weighing 50-100 kg). They are relatively inexpensive, easily modified to solve various problems, can be launched into space by light-class carriers or simultaneously, up to dozens, by heavier rockets. The use of small spacecraft is financially more advantageous in the event of an accident during launch or failure when working in orbit. Given the low price of such devices, multisatellite systems can be formed from them for communication, continuous monitoring of the earth's surface, scientific research, etc.

The requirements for modern small spacecraft include, as a rule, triaxial orientation in a given coordinate system, which provides targeted use in such areas as remote sensing of the Earth, astrophysical and geophysical studies.

The most widely known systems with gas-jet nozzles or other micro-jet engines. However, they have a significant drawback - the flow of the working fluid, as a result of which the useful time for the functioning of the spacecraft is limited and, in addition, for small spacecraft these systems are almost unacceptable due to the presence of a working medium that increases the mass and dimensions of the spacecraft.

Therefore, for small spacecraft, the most acceptable control devices are, for example, flywheel engines, often used in spacecraft orientation and stabilization systems (see RF patent No. 1839928), which are characterized by high stabilization accuracy, small size, ease of control, and the absence of non-renewable flow working fluid. Flywheel engines create an internal control torque (create a mechanical moment around an axis parallel to the axis of rotation of the rotor of the flywheel engine) and cannot fend off external disturbances. They are inertial carriers of the kinetic moment (hereinafter referred to as inertial executive bodies). Therefore, one of the drawbacks of engines of this type is the need to reset the kinetic moment of the flywheels when they reach the maximum rotational speeds. In the event that some external moment (aerodynamic drag forces, light pressure, gravitational field or other external forces) acts on the satellite’s body, then the body acquires a certain angular velocity around any axis over a period of time. This "parasitic" speed can be eliminated only by an external moment (A. G. Iosifyan, Electromechanics in space. "Cosmonautics, Astronomy" No. 3, 1977). Physically, this means that “parasitic” rotation is stopped if the kinetic moment obtained by the housing is translated “inward”, starting, for example, the rotor of the flywheel engine in the direction in which the external force and external torque acted.

To reset the kinetic moment, a magnetic system is used, which includes magnetic actuators (in space technology, electromagnets, permanent magnets, current inductors, superconducting magnets), which form magnetic moments, which, interacting with the geomagnetic field, create controlling mechanical moments. These control mechanical moments provide the reset of kinetic moments from flywheel engines.

Thus, when creating small spacecraft, the development of a highly efficient system for resetting the kinetic moments of inertial actuators, which provide orientation and stabilization of small spacecraft with a given accuracy, with small mass and dimensions, without the expense of the working fluid and with minimal energy costs, is very relevant.

In the general case, the control moment M is determined by the basic control equation (see A. P. Kovalenko. Magnetic control systems for spacecraft. M., Mashinostroyenie, 1975, p. 21):

M = L × B,

where L is the vector of the generated magnetic moment by the magnetic system;

B is the vector of magnetic induction of the Earth's magnetic field.

For example, to solve the problem of unloading the kinetic moment of inertial actuators, a method is known for magnetic unloading of inertial actuators of a spacecraft and a device for its implementation (RF patent No. 2070148). According to the technical solution of this analogue, the method of magnetic unloading of the inertial executive bodies of the spacecraft consists in creating a magnetic moment by the magnetic system, rotating this system around one of the spacecraft axes, determining the vectors of the kinetic moment accumulated by the executive bodies and magnetic induction of the Earth’s magnetic field, and then rotating the magnetic system around the second axis perpendicular to the specified axis and the magnetic moment vector.

A device for magnetic unloading of inertial executive bodies of the spacecraft according to this method comprises a magnetic system connected to the spacecraft with a suspension of the magnetic system, including a rotation drive that rotates the specified system around one of the spacecraft axes, and a spacecraft control system. It is also equipped with a means for determining the magnetic flux density vector of the Earth’s magnetic field, sensors of kinetic moment accumulated by the executive bodies, the inputs of which are connected to the specified control system, a magnetic moment determining unit, the inputs of which are connected to these sensors, with means for determining the magnetic induction vector, and with the specified control system. The suspension is equipped with a second rotation drive that rotates the magnetic system around an axis perpendicular to the specified axis and a vector of the magnetic moment generated by the system, while the device further comprises a unit for determining the rotation angles of the magnetic system around these axes, the inputs and outputs of which are connected via converting elements to the indicated rotation drives magnetic system, and these inputs are also connected to the unit for determining the magnetic moment. A superconducting short-circuited inductance coil with a direct current circulating through it and a cryogenic support system are used as a magnetic system.

The disadvantage of this method and device for carrying out magnetic unloading of inertial executive bodies of the spacecraft is the large mass and dimensions due to the presence of a suspension, drives, block for determining rotation angles, cryogenic support system, high power consumption. Therefore, its use for small spacecraft weighing up to one hundred kilograms is not an optimal solution.

Closest to the proposed invention is the device of a magnetic system for resetting the kinetic moment (A. P. Kovalenko. Magnetic control systems for spacecraft. M., "Engineering", 1975, pp. 103-105), taken as a prototype.

1. A method of resetting the kinetic moment of inertial actuators of the spacecraft, which consists in determining the vectors of the kinetic moment accumulated by inertia actuators and magnetic induction of the Earth’s magnetic field along the three coordinate axes X, Y, Z, generating control signals for the magnetic actuator, at the outputs of which magnetic moments along the three coordinate axes X, Y, Z, determined by the voltage of the power source.

2. The device contains sensors of the components of the kinetic moment along the three coordinate axes X, Y, Z, sensors of the components of geomagnetic induction along the three coordinate axes X, Y, Z, a control unit, to the inputs of which these sensors are connected, and to the outputs are three groups of series-connected relay element and magnetic actuator.

At the outputs of the sensors of the components of the kinetic moment along the three coordinate axes X, Y, Z, signals of the kinetic moments accumulated by inertial actuators K _x , K _y , K _{z are formed} , and at the outputs of the sensors of geomagnetic induction along the three coordinate axes X, Y, Z, respectively, magnetic induction B _x , B _y , B _z , and according to the data obtained at the output of the control unit along the three coordinate axes X, Y, Z, signals σ _x , σ _y , σ _{z are formed} ,

Where

σ _x = K _y B _z -K _z B _y ;

σ _y = K _z B _x -K _x B _z ;

σ _z = K _x B _y -K _y B _x .

These signals σ _x , σ _y , σ _z enter the relay elements, in which they are compared with the threshold signal σ ₀ .

When σ _i (i = x, y, z)> σ _{0, the} corresponding relay element includes a magnetic actuator, the output of which creates control magnetic moments relative to the coordinate axes of the spacecraft: L _x , L _y , L _z .

As electromagnets in magnetic actuators, for example, rod-type electromagnets can be used, i.e. inductors are wound on the core core.

The generated magnetic moment, interacting with the Earth's magnetic field, creates a controlling mechanical moment M, with coordinate components:

M _x = L _y B _z -L _z B _y ;

M _y = L _z B _x -L _x B _z ;

M _z, = L _x B _y -L _y B _x .

The prototype device provides high reliability, because the position of the control moment vector, orthogonal to the axis of the electromagnet, provides some redundancy of the system, which consists in the ability of the system to reset the kinetic moment of any direction with a slight decrease in performance when the electromagnet fails in one coordinate axis and if the magnetometer path of the other coordinate axis fails. This is explained by the fact that each electromagnet located parallel to the coordinate axis, in the presence of three coordinate components of geomagnetic induction, can create control moments directed along the other two coordinate axes.

Under unloading conditions, σ _i (i = x, y, z) <σ _{0, the} electricity consumption is carried out mainly by the logic circuit. However, for σ _i (i = x, y, z)> σ ₀ , when the corresponding relay element includes a magnetic actuator, regardless of the magnitude of the components K _x , K _y , K _z (σ _x , σ _y , σ _z ) in each coil X, Y, Z flows current, determined by the constant voltage of the power source. This entails excessive power consumption.

The aim of the invention is to reduce energy consumption during the reset of the kinetic moment of inertial actuators of the spacecraft by magnetic actuators.

Disclosure of invention

The essence of the method for resetting the kinetic moment of the inertial actuators of the spacecraft consists in determining the values of the kinetic moment accumulated by the inertia actuators and magnetic induction of the Earth’s magnetic field along the three coordinate axes X, Y, Z and the formation of the control magnetic moment signals at the outputs of the magnetic actuator in accordance with the values the kinetic moment accumulated by inertial actuators, respectively, along each coordinate axis X, Y, Z.

The essence of the proposed device for resetting the kinetic moment of inertial actuators of the spacecraft consists in the technical provision in each coil X, Y, Z of the magnetic actuator of the current strength in accordance with the values of the kinetic moment K _x , K _y , K _z , (σ _x , σ _y , σ _z ) determined by the sensors of the components of the kinetic moment, respectively, along each coordinate axis X, Y, Z.

The device for resetting the kinetic moments of the inertial executive bodies of the spacecraft includes sensors of the components of the kinetic moment along the three coordinate axes X, Y, Z, sensors of the components of geomagnetic induction along the three coordinate axes X, Y, Z, a control unit (BU), to the inputs of which are mentioned sensors, magnetic actuators, at the outputs of which magnetic moments are formed.

The introduction of three digital-to-analog converters (DACs) into the device for resetting the kinetic moment of inertial actuators of the spacecraft, the inputs of which are connected to three outputs of the control unit, three comparators, the first inputs of which are connected to the outputs of the DAC, and the signal σ ₀ , three elements the first inputs of which are connected to the outputs of the comparators, and the second inputs are connected to the fourth output of the control unit, three electronic keys, the inputs of which are connected to the outputs of the DAC, the control inputs of the electronic keys are connected to the outputs of the elements And, and the outputs are connected to the inputs of the magnetic actuators, containing serially connected reversing switches and electromagnets, which ensures the required magnetic induction at the output of the magnetic actuators along each coordinate axis X, Y, Z in accordance with the values of the kinetic moment K _x accumulated by inertial actuators, K _y , K _z .

, который разрешает прохождение сигналов σ_i, соответствующей логической "1" через элементы И при сигнале запрета a _o, соответствующей логической "1" (описание с наглядной иллюстрацией по формированию сигнала запрета а _o будет приведено ниже). Это условие сравнения необходимо для того, что в случае, когда паразитный момент больше полезного, устройство может не только не сбрасывать кинетический момент, а напротив, увеличивать его (паразитные возмущения при включении магнитных исполнительных органов возникают в следствие того, что механический момент, создаваемый взаимодействием магнитного поля с геомагнитным полем, всегда перпендикулярен вектору геомагнитной индукции, поэтому в общем случае он не может быть параллельным вектору кинетического момента, направление которого произвольно, и, следовательно, вектор механического момента представляет собой сумму двух составляющих - полезной составляющей, вектор которой параллелен вектору кинетического момента и направлен в противоположную сторону, и паразитную составляющую, вектор которой перпендикулярен вектору кинетического момента).DACs allow the formation of current strength (magnetic induction, which is proportional to the current strength) in each coil X, Y, Z of an electromagnet proportional to the voltage values at the DAC outputs, which correspond to the values of the kinetic momentum K _x , K _y , K _z , (σ _x , σ _y , σ _z ) determined by the sensors of the components of the kinetic moment on each coordinate axis X, Y, Z, respectively. The voltage supply from the DAC outputs through open electronic keys is provided by the comparator for σ _i (i = x, y, z)> σ _o under the conditions when useful Mechanical Protection moment M _floor exceeds parasitic M _pairs, i.e. a prohibition signal is generated in the control unit

, which allows the passage of signals σ _i corresponding to the logical "1" through the AND elements with the inhibit signal a _o corresponding to the logical "1" (a description with a clear illustration of the formation of the inhibit signal a _o will be given below). This comparison condition is necessary so that in the case when the stray moment is more than useful, the device can not only not reset the kinetic moment, but, on the contrary, increase it (stray disturbances when magnetic actuators are turned on arise due to the fact that the mechanical moment created by the interaction of a magnetic field with a geomagnetic field is always perpendicular to the vector of geomagnetic induction, therefore, in the general case, it cannot be parallel to the vector of the kinetic moment, the direction of which Accidental, and therefore a mechanical moment vector is the sum of two components - a useful component, which is parallel to the vector of the angular momentum vector and directed in the opposite direction, and a parasitic component, which is perpendicular to the vector of angular momentum).

Given the development trend of microelectronics and software, the most optimal is the digital way to execute the control unit. This is facilitated by the requirements of GOST R 52070-2003 on the use of standardized interfaces of serial multiplexed communication channels (MCO), which include an on-board computer with system and local controllers.

Thus, thanks to the introduction of new features - three DACs, three comparators, three AND elements and three electronic keys, the magnetic actuators generate inconstant (maximum) ones, like the prototype, and the optimum magnetic inductions are required for each coordinate axis X, Y, Z. This saves energy consumption by magnetic actuators, and as a result, their heat is reduced. In addition, an optimal control mechanical moment is created, which causes the spacecraft to deviate from its oriented position when the kinetic moment is unloaded. In general, this determines the economical mode of energy consumption and the optimal mode of operation of the spacecraft orientation system.

Graphic illustration

Figure 1 shows, as a graphic illustration, a block diagram of the device for resetting the kinetic moment of inertial actuators of the spacecraft, and figure 2 shows the components of the vectors of kinetic moment and geomagnetic induction in the YZ plane and useful and spurious mechanical moments created by the magnetic axis X axis.

Description of the method for resetting the kinetic moment of inertial executive bodies of the spacecraft

The values of the kinetic moment accumulated by inertial actuators and the magnetic induction of the Earth’s magnetic field are determined along the three coordinate axes X, Y, Z. Control electric signals and supply voltages for the magnetic actuators along each coordinate axis X, Y, Z are formed, which provide the current strength in the coils electromagnets of magnetic actuators in accordance with the values of the kinetic moment accumulated by inertial actuators, respectively, for each coordinate X, Y, Z axis. Magnetic moments are formed at the outputs of the magnetic actuators, which, when exposed to a geomagnetic field, create controlling mechanical moments to reset the kinetic moment accumulated by the inertial actuators in the optimal energy consumption mode.

Device Description

The device for resetting the kinetic moment of the inertial actuators of the spacecraft contains blocks indicated by the positions in FIG. one:

sensors of components of geomagnetic induction along the three coordinate axes X, Y, Z - 1, 2, 3;

sensors of the components of the kinetic moment along the three coordinate axes X, Y, Z - 4, 5, 6;

control unit 7;

digital-to-analog converters - 8, 9, 10;

comparators - 11, 12, 13;

elements And - 14, 15, 16;

electronic keys - 17, 18, 19;

reverse switches - 20, 21, 22;

electromagnets - 23, 24, 25.

The device operates as follows. As in the prototype, the sensors of the components of geomagnetic induction along the three coordinate axes X, Y, Z (1, 2, 3) generate signals of the coordinate components of the induction B _x , B _y , B _z , and the sensors of the components of the kinetic moment along the three coordinate axes X, Y , Z (4, 5, 6) measure the kinetic moments of inertial actuators (flywheel engines) and generate signals K _x , K _y , K _z .

As sensors, components of geomagnetic induction can be used, for example, a three-component digital magnetometer MTTs-8 developed by Ramenskoye Instrument-Making Design Bureau JSC.

Angular velocity sensors can be used as sensors of the kinetic moment components (see RF patent No. 2070148).

Based on the incoming signals, the control unit 7 generates signals equal to

σ _x = K _y B _z -K _z B _y ;

σ _y = K _z B _x -K _x B _z ;

σ _z, = K _x B _y -K _y B _x .

The control unit 7 is a structurally complete microprocessor unit (for example, based on a microprocessor of the ADSP 2189NBCA-320 type) having communication devices, a software package (or can be performed, for example, on a domestic single-chip microcomputer of the 1816 series).

These signals σ _x , σ _y , σ _z in digital form are input to the DAC inputs (8, 9, 11), at the outputs of which voltage values corresponding to digital codes are generated. DAC with voltage output can be performed, for example, on the chip KSh8PA2.

When the condition σ _i (i = x, y, z)> σ _o (σ _o is the threshold signal) is fulfilled, the logical 1 signals are generated at the output of the comparators (11, 12, 13). The threshold signal σ _o can be generated, for example, in the control unit 7. The comparator can be performed, for example, based on the LM339 voltage comparator microcircuit. This logical “1” signal is fed to the inputs of the AND elements (14, 15, 16) and when the prohibition signal a _o appears on the second inputs of the data of the AND elements, the corresponding logical “1” signal appears on the outputs of the AND elements (14, 15, 16) a control signal (AND elements can be performed, for example, on a K155LA8 chip with an open collector output), which opens electronic keys at the control inputs (17, 18, 19) (electronic keys can be made, for example, in the form of transistor keys). Through these open electronic keys (17, 18, 19), the voltages from the outputs of the DAC (8, 9, 11) are supplied to the reversing switches (20, 21, 22) and are the supply voltage, resulting in electromagnets (23, 24, 25 ) current strengths are formed, which are directly proportional to the given values of the supply voltages (values at the outputs of the DAC 8, 9, 11), i.e. Signals σ _x , σ _y , σ _z . At the outputs of electromagnets (23, 24, 25), magnetic moments are generated relative to the coordinate axes of the spacecraft: L _x , L _y , L _z , the values of which are respectively proportional to the signals σ _x , σ _y , σ _z .

Reversible switches (20, 21, 22) can be made, for example, in the form of a bridge switch and provide reverse control of electromagnets (23, 24, 25). A description of the operation of reversible switches is given in RF patent 2140128. For example, rod-type electromagnets (core made of soft magnetic material with windings of copper wire) can be used as magnetic actuators.

To clearly illustrate the formation of the inhibit signal a _o , Figure 2 shows a graphical representation of the components of the kinetic moment and geomagnetic induction vectors in the YZ plane and useful and spurious mechanical moments created by the magnetic axis.

^- K _YZ - component of the kinetic moment vector;

^- B _YZ - component of the geomagnetic induction vector.

The factor B _YZ Sinγ is equal to the magnitude of the vector component ^- In _YZ , perpendicular to the vector ^- To _YZ . This component of geomagnetic induction when you turn on the magnetic actuator, which forms the magnetic moment L _x , creates a useful mechanical moment ^- M _floor . The value of B _YZ Cosγ is equal to the projection of the vector ^- B _YZ on the direction of the vector ^- K _YZ . When the magnetic actuator is turned on, this component of geomagnetic induction is the cause of a parasitic mechanical moment ^- M _pairs , the direction of which is perpendicular to the component ^- K _YZ . The inhibit signal a _o corresponds to the logical signal "1" under the condition ^- M _floor > ^- M _pairs .

Thus, the formation of the optimally required current strength in electromagnets along each coordinate axis X, Y, Z and, accordingly, the values of magnetic inductions along each coordinate axis X, Y, Z in accordance with the values of σ _i (i = x, y, z) are achieved. As a result, energy consumption is reduced due to energy saving by the magnetic actuators, heat generation is reduced and a more optimal controlling mechanical moment is created, causing the spacecraft to deviate from its oriented position when unloading the kinetic moment.

In general, this determines the economical mode of energy consumption and the optimal mode of operation of the spacecraft orientation system.

Claims (2)

1. A method for resetting the kinetic moment of inertial actuators of the spacecraft, which consists in determining the vectors of kinetic moments accumulated by inertia actuators and magnetic induction of the Earth’s magnetic field along the three coordinate axes X, Y, Z and generating control signals for the magnetic actuator, at the outputs of which magnetic moments along the three coordinate axes X, Y, Z, determined by the voltage of the power source, characterized in that they form the control electric signals and pits voltage for the magnetic actuator on each coordinate axis X, Y, Z, providing currents in the coils of the electromagnets of the magnetic actuator in accordance with the values of the kinetic moment accumulated by inertial actuators respectively on each coordinate axis X, Y, Z, while the outputs of the magnetic actuator are generated magnetic moments, which, interacting with the Earth's magnetic field, create controlling mechanical moments to reset the kinetic moment, akoplennogo inertial executive bodies in the optimal mode for power consumption. 2. A device for resetting the kinetic moment of the inertial executive bodies of the spacecraft, including sensors of the components of the kinetic moment along the three coordinate axes X, Y, Z, sensors of components of geomagnetic induction along the three coordinate axes X, Y, Z, a control unit, to the inputs of which the above-mentioned are connected Sensors a magnetic actuator, at the outputs of which signals of control magnetic moments are generated, characterized in that three digital-to-analog converters are introduced, the inputs of which are connected to three outputs of the control unit; three comparators, the first inputs of which are connected to the outputs of digital-to-analog converters, and a threshold signal is supplied to the second inputs; three AND elements, the first inputs of which are connected to the outputs of the comparators, and the second inputs are connected to the fourth output of the control unit; three electronic keys, the inputs of which are connected to the outputs of the digital-to-analog converters, while the control inputs of the electronic keys are connected to the outputs of the And elements, and the outputs of the electronic keys are connected to the inputs of the magnetic actuators, containing reversible switches and electromagnets connected in series.

Images