RU2711819C2 - Spacecraft movement control method - Google Patents

Abstract

FIELD: astronautics.SUBSTANCE: invention relates to combined control of centre of mass movement and angular orientation of spacecrafts using low-thrust engines. Engines are arranged in pairs symmetrically to the plane of axes of roll and yaw of the spacecraft, and the lines of action of their rods pass through the centre of mass of the spacecraft and are directed at an angle to the main axes of inertia of the spacecraft. Engines of pair are deviated from plane of axes of pitch and roll by some angle, and from plane of axes of pitch and yaw - at some other angle. Engines that create opposite transversal accelerations are successively turned on. Orbit section and duration of required engine activation are selected depending on current position of orbit inclination vector. Traction direction is selected based on minimum flow rate of working medium with minimum effect on spacecraft structure elements.EFFECT: technical result is optimization of working medium flow rate for spacecraft retention by latitude and longitude, reduction of mass of electric propulsion plant and reduction of disturbing moments caused by action of engine jets.1 cl, 4 dwg

Description

The invention relates to the field of space technology and can be used in controlling the movement of spacecraft (SC).

Currently, various means and methods for controlling the motion of the spacecraft are known, which are used to correct the orbit of the spacecraft, stabilization and orientation of the spacecraft. Control systems can vary significantly in design, energy consumption, type of executive bodies, depending on the control tasks being solved, the mass of the spacecraft and its orbit of movement, as well as on the duration of the corrective maneuvers. The spacecraft control system can simultaneously control both the motion of the spacecraft's center of mass and the spacecraft’s motion control relative to its spacecraft center of mass.

The closest analogue is “A method for controlling the motion of a spacecraft and a control system” (patent for invention RU 2309876 C1). A method for controlling the motion of a spacecraft, which consists in controlling the motion of the center of mass of the spacecraft and in controlling the angular orientation of the spacecraft in space, including a control action on the spacecraft by turning on at least one small thrust jet engine of the propulsion system of the spacecraft creating a thrust vector relative to the three main orthogonal axes of inertia of the spacecraft. Control actions are created using small thrust engines located in the common installation plane of the spacecraft, orthogonal to one of its inertia planes, with an angular displacement between the nearest engines.

A number of significant disadvantages characteristic of the prototype is as follows:

1. the efficiency of the use of the thrust given in the examples of implementation of the invention is achieved through the use of two small thrust engines, which leads to an increase in the required power of the power plant of the spacecraft, because the orbit correction takes 1.5-3 hours per day, the rest of the time the power of the power plant will not be used, which leads to the non-optimality of the designed spacecraft;

2. The engines are placed evenly on the spacecraft body. During the creation of the control action, the jet of the engine will create disturbing moments when it affects the elements of the spacecraft (solar panels, antennas, etc.), which must be compensated for by controlling the angular position of the spacecraft and, accordingly, require additional resources of spacecraft (fuel).

The tasks to be solved by the claimed invention are directed:

1. A decrease in the mass of the spacecraft by reducing the mass of the propulsion system;

2. The reduction of disturbing moments created by small thrust engines during the creation of the control action;

3. A decrease in the mass of the spacecraft due to the optimal use of the power plant of the spacecraft;

To solve this problem, a method for controlling the motion of a spacecraft is proposed, which consists in controlling the motion of the center of mass of the spacecraft and in controlling the angular orientation of the spacecraft in space, including a control action on the spacecraft by turning on at least one small thruster, propulsion system spacecraft, creating a thrust vector relative to the three main orthogonal axes of inertia of the spacecraft. Control actions are created using small thrust engines, arranged in a pair symmetrically with respect to the plane of the roll and yaw axes of the spacecraft. The lines of action of the engine rods are directed at an angle to the main axes of inertia, each pair of engines is deviated from the plane of the pitch and roll axes by a degree, and the vector of the rods of each of the engines in the planes of the pair of engines are deviated from the plane of the pitch and yaw axes by | 3 degrees.

In particular cases of the invention, each motor is mounted on the drive and is able to change its angular position. Changing the direction of the thrust vectors allows you to create control moments of thrust relative to the three main orthogonal axis of inertia of the spacecraft.

Using these capabilities allows during operations to control the center of mass of the spacecraft to quench the kinetic moment (unloading) of the inertial controls of the spacecraft, for example, gyroscopic power stabilizers (flywheels).

Using these features allows you to make software turns of the spacecraft during orientation.

Technical results provided by the given set of features are:

1. weight reduction of the spacecraft power plant, which is achieved by using the spacecraft motion control method, which assumes the optimal orientation of the thrust vector when one engine is turned on, as a result, a more optimal design of the spacecraft;

2. reducing the mass of the propulsion system by reducing the number of thrusters;

3. reduction of disturbing moments from the action of engine jets, as angles α and β are selected based on the priority condition for minimizing fuel consumption and the additional condition of minimal impact on the structural elements of the spacecraft.

The invention is illustrated by drawings, which depict:

- in FIG. 1 - shows a schematic view of a satellite;

- in FIG. 2 - schematically shows the spacecraft body with installed engines (top view);

- in FIG. 3 - schematically shows the spacecraft body with installed engines (side view);

- in FIG. 4 - schematically shows a special case of the invention, at different angles of installation of small thrust engines.

A method of controlling the motion of a spacecraft 1, which consists in controlling the motion of the center of mass of the spacecraft and in controlling the angular orientation of the spacecraft in space, including a control action on the spacecraft by turning on at least one small thrust jet engine 2 of the propulsion system of the spacecraft, creating thrust vector relative to the three main orthogonal axes of inertia of the spacecraft. Control actions are created using small thrust engines 2 located in a pair symmetrically with respect to the plane of the roll axes and the yaw of the spacecraft 1. The action lines of the engine thrusts are directed at an angle to the main axes of inertia, each pair of engines deviates from the plane of the pitch and roll axes by α degrees 3, and the thrust vector of each of the engines in the planes of the pair of engines is deviated from the plane of the axes of pitch and yaw by β degrees 4.

Obtaining technical results is guaranteed by applying the following strategy of spacecraft retention in geostationary orbit in latitude and longitude.

The strategy for spacecraft retention corrections in latitude and longitude should minimize fuel consumption. The analysis shows that the main fuel costs in the interval of long-term spacecraft operation (15 years or more) are associated with its latitude retention.

To save the velocity impulse, all short-period components of the perturbation of the inclination vector are allocated to the unadjustable group. Latitude retention corrections compensate for the secular component of the change in the inclination vector due to lunar-solar disturbances.

The directions of the engine thrust vectors are selected based on the minimum fuel consumption per CAC and the minimum influence of the engines on the spacecraft elements.

To correct the latitude, such sections of the orbit and the duration of the correction engines (DC) are selected in order to optimally change the inclination vector. At each turn of the flight, theoretically, there are two such sections of the orbit (180 ° apart in the argument of latitude). At the same time, the operation time of the correction engines in both sections is the same, and the directions of corrective accelerations in the North-South direction are opposite. The choice of the orbit section, the duration of the DC operation depend on the current position of the inclination vector of the spacecraft and the parameters of the retention strategy.

Longitude spacecraft retention is reduced to corrections of the spacecraft's orbital period and orbital eccentricity, which should compensate for the influence of disturbing forces, primarily the off-center gravitational field of the Earth and light pressure.

The layout of the DC is such that when the inclination vector is corrected, the eccentricity vector and sidereal period also change. The necessary change in the circulation period is provided by either selecting an engine (having the required sign of transverse acceleration) or sequentially turning on two engines having opposite transverse accelerations.

As for the control of the eccentricity vector, the following algorithm can be used:

a) At the turn, correction of the inclination with one switch-on is planned, in which a change in the circulation period in the desired direction is provided. Of the two possible options (the engine of the "north" or the engine of the "south" direction), that portion of the orbit is selected where, at least, the eccentricity does not deteriorate.

b) If one engine does not provide the required change in the circulation period, then the maneuver is calculated for a pair of engines of the same direction in the north (south). At the same time, from two possible pairs of inclusions (motors of the "northern" or "southern" direction), the most optimal for eccentricity is selected

c) If the inclination corrections are not enough and the eccentricity is greater than the specified threshold value, then the eccentricity correction at the turn is planned with two inclusions separated by 12 hours. For this, the engines are switched on at the sites of the orbit that are optimal for changing the eccentricity (in the vicinity of perigee and apogee, for example). At the same time, the period of revolution and the eccentricity of the orbit change.

Claims (2)

1. The method of controlling the motion of the spacecraft, which consists in controlling the motion of the center of mass of the spacecraft by means of small thrust jet engines of its propulsion system, creating a thrust vector relative to the three main axes of inertia of the spacecraft, characterized in that the control action is formed taking into account the compensation of external disturbing forces by the sequential inclusion of small thrust engines that create opposite transverse accelerations and located at an angle only the plane of the pitch and roll axes, as well as the plane of the pitch and yaw axes of the spacecraft, at a given point in time, while the selection of the orbit section to turn on a specific thruster and its duration is carried out depending on the current position of the inclination vector of the orbit, choosing the direction of the vectors engine thrust based on minimum fuel consumption with minimal impact on the elements of the spacecraft. 2. The method according to p. 1, characterized in that the jet thrusters can be plasma, ion or electric arc.

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