RU1811500C - Method of controlling the space object orientation - Google Patents

Abstract

Usage: precision orientation systems of space objects of relay type. SUMMARY OF THE INVENTION: When using orientation to create control moments of a flywheel, the angular speed of rotation of the flywheel is measured, determining its boundary value in the state of motion, when the entire kinetic moment is concentrated in the flywheel, and the reduction in the value of control moment is performed when the measured value coincides angular velocity with its specified boundary value, and the flywheel engine is turned on whenever the orientation system leaves the dead zone and is turned off when entering this zone, 1 zp f-ly, 1 ill.

Description

The invention relates to control means of aircraft and can be used for precise orientation in space of space objects (CO).

The purpose of the invention is to simplify the implementation of the method and increase its noise immunity.

The invention is illustrated in the graphic materials, where in FIG. the phase plane is shown in the coordinates of the angular deviation of the object p and the angular velocity of the object p for one stabilization channel, and the straight lines and correspond to the upper and lower threshold values of the angular deviation. A portion of the plane enclosed between these lines is a dead zone.

The method according to the invention is carried out as follows. Suppose that at the beginning of the control process the object is at point 1 of the phase plane (Fig.). Suppose that at a given moment in time, a kinetic moment K is accumulated on this control channel. Then at point 1 the equality holds:

K l (p + O, (1)

where the indices indicate a point on the phase plane.

1 and i are the moments of inertia of the object with the flywheel and the flywheel separately, respectively, and Q is the angular velocity of the flywheel.

Since point 1 is outside the deadband, apply to

ate about

Sd

This control moment by turning on the poppy engine. The change in the phase state of the object will occur along a phase trajectory 1-2, which at a constant value of the control moment is a parabola with a symmetry axis b. At point 2, the object falls into the dead zone, and the flywheel engine is turned off. The change in the phase state of the object will occur along a phase trajectory 2-3 (either by inertia or by the action of a certain disturbing moment, as shown, for example, in the figure). At point 3, the object leaves the dead zone, and turn on the flywheel. The phase trajectory will be symmetrical about the parabola axis 3-4-5, and therefore the following relationships are true:

and

K I rz + I K I FA + I K G jp5 + - 0.

  -.

because the kinetic moment K is a slowly varying quantity, and therefore K const is taken.

From expressions (2) we obtain

i OI K

Qj-Oz

Qj

those. at point 4 of the phase trajectory lying on the 04 axis (phi 0), the accumulated kinetic moment is concentrated in the flywheel of the flywheel, and the angular velocity of rotation of the flywheel, which we will call critical, is equal to the arithmetic mean of two values of the angular velocities of rotation of the flywheel, measured at successive intersections of the fixed boundary of the deadband in mutually opposite directions, it should be noted that this conclusion was made under the assumption that the control moment is constant in magnitude. Thus, at all points lying on the axis at K const, the same value of the angular velocity of rotation of the flywheel of the flywheel engine takes place.

At point 5, when entering the dead zone, the flywheel engine is turned off and similarly - as after point 2 - the object moves by inertia (with a constant

10

fifteen

twenty

speed) or - as in FIG. - under the influence of a disturbing moment to point 6.

At point b, when leaving the dead zone, turn on the flywheel engine, measure the angular velocity of its rotation Q and compare it with the critical one, i.e. ABOUT) ; movement occurs along parabola 6-7. At point 7, the angular velocity O / becomes equal to critical — the amount of control torque is reduced, for example, frequency modulation (average decrease) of control torque is performed. In connection with a decrease in the control moment of the object's movement on the phase plane, a parabola 7-8 will be displayed with a lower slope than parabola 6-7, with the same angular deviation from the apex. In this regard, the angular velocity at point 8 in absolute value is less than at point 6, i.e.

(2)

/ p & I / fv I

(4)

25

thirty

35

40

45

fifty

55

At point 8, when entering the dead zone, the flywheel engine is turned off. If the angular velocity / (pj / is sufficiently small, then the phase trajectory can take the form 8–9–10, i.e., the perturbing moment will again lead the object out of the dead zone to p 0. Since the perturbing moment is in a small time interval (the motion time on plot 8-9-10) can be taken constant in magnitude, then similarly, as on plot 3-4-5, you can determine the boundary value of the angular velocity of rotation of the flywheel O- as follows:

o - o - o, - Oz + Ј2yu S.4- & & - b # - ---

where O & and QIO are the measured and stored values of the angular velocity of the flywheel when entering and leaving the dead zone. From expressions 3 and 5 it follows that the boundary value of the angular velocity of rotation of the flywheel can be determined by measuring two values of the angular velocity of rotation of the flywheel by successively crossing the fixed boundary of the dead band in mutually opposite directions and calculating the arithmetic mean of these two values, while so that in the time interval between the indicated measurements of the two values of the angular velocity, a constant momentum is applied to the object: control plus disturbing singing (outside the dead band) or only disturbing (inside the dead band).

At point 10, when leaving the dead zone, the flywheel is turned on, the angular velocity of rotation Q is measured; the movement takes place on a parabola 10-11. When the equality Qn Or is satisfied at point 11, the magnitude of the control moment is reduced, similarly to that at point 7. Due to the decrease in the moment at point 11, the magnitude of the angular velocity of the object at point 12 will be smaller in absolute value than at point 10:

/ I I ryu /

those. a similar effect as on trajectory 6-7-8 (see expression (4).

This effect is always achieved when the control torque decreases after the angular speed of rotation of the flywheel reaches a limit value.

As can be seen from the diagram, if the angular velocity of the object at the entrance to the dead zone is less than the speed of exit from the dead zone, this control process leads to vibration damping, and the vibration amplitudes of the object decrease both in speed p and in angular deviation p .

With a constant accumulated value of the kinetic momentum K, as can be seen from the first expression 3, the boundary value of the angular velocity of rotation of the flywheel will be constant, and to control the orientation, it is sufficient to determine it once. In fact, over time, under the influence of an external disturbing moment, the value of K changes, and therefore it is necessary to repeat - and thus refine - the boundary value of the angular velocity of rotation of the flywheel during the orientation control process.

The instrument method is implemented, for example, as follows.

Using a purely relay angular deviation measuring device, a relay signal is generated defining the upper and lower angular deviation thresholds. If there is no relay signal, then the flywheel motor is not turned on. When a relay signal appears - depending on which threshold - upper or lower - the flywheel engine is turned on in one direction or the other. The angular speed of rotation of the flywheel is measured, for example, using a tachogenerator. Two angular values are stored soon.

the rotation of the flywheel during successive occurrences and disappearances (disappearances and occurrences) of the relay signal corresponding to the same threshold

5 (top or bottom). The arithmetic average of these two values is calculated, i.e. the limit value of the angular speed of rotation of the flywheel is determined. Then, each time when, in the presence of a relay signal, the angular speed of rotation of the flywheel becomes equal to the boundary value, the absolute value of the control torque developed by the flywheel motor is reduced. The boundary value is periodically monitored (determined) over time.

Thus, the method is implemented instrumentally using a pure relay

20, an angular deviation measuring device that implements only the upper and lower angular deviation thresholds. Such devices are much simpler and more reliable and more noise-resistant than measuring instruments of continuous or discrete measurement.

Claims (1)

1. A method for controlling the orientation of a space object, including the formation of a relay signal from the angular deviation of the object in one of the stabilization channels, applying a control moment to the object by switching on 35 of the flywheel orientation motor, reducing the control torque outside the dead band, limited by the upper and lower threshold values of angular deviation, with a maximum of 40 degrees, and so that, in order to simplify the implementation of the method and increase its noise immunity, measure the angular velocity of rotation of the flywheel in the flywheel engine, determining its boundary value in the state of angular motion, when the entire kinetic moment is concentrated in the flywheel, and the decrease in the control torque t at coincidence of the current measured value of the angular 50, the speed of rotation of the flywheel with the specified boundary value, the flywheel engine being turned on whenever it leaves the dead zone and turned off when entering this zone. 552. The method of claim 1, wherein the boundary value of the angular speed of rotation of the flywheel is determined by measuring two values of the angular velocity of rotation of the flywheel at successive intersections of a fixed boundary of the dead band in mutually opposite the arithmetic mean of these two significant directions and the calculations.