GB2203223A - Control means - Google Patents

Abstract

Means for controlling a flight vehicle (for example a guided weapon) which in flight is subject to both a rotation about an axis (for example the roll axis) and to acceleration normal to that axis including movable ballast means, housable within the vehicle which include a first mass movable in a plane including the axis of rotation, and a second mass movable in a plane including the axis of rotation and normal to the first plane, both masses being movable in response to the direction of the rotation and to the direction of the acceleration so that a torque opposing the rotation is generated.

Description

Title: Control and/or Stabilising Means This invention relates to means for aiding the biEbility and/or control of flight vehicles which are (subject, in flight, both to rotation about an axis and to acceleration normal to that axis.

when providing a flight vehicle with means for aiding its stability and/or control such as fins, aerofoil surfaces, gas jets, and exhaust deflector devices it has been found that their operation can upset the aerodynamic characteristics of the vehicle and introduce flight instability.

It is an object of the present invention to provide means for aiding stability and/or control which do not affect the aerodynamic characteristics of the vehicle.

According to the present invention means for aiding the stability and/or control of a flight vehicle which is subject, in flight, both to a rotation about an axis and to acceleration normal to that axis, includes, combination movable ballast means housable within the vehicle, sensing means arranged in use to sense the direction of said rotation and the direction of said acceleration, and actuation means responsive to an output of the sensing means to so position the ballast means within the vehicle that a torque opposing said rotation can be generated.

Preferably the ballast means includes a first zss movable such that its effective centre of gravity moves in a first vlane normal to the axis of rotation, and a second ;-ss movable such that its effective centre of gravity moves in a second plane normal to the aris of rotation srd nor'-l to the first plane One preferred example of the invention is described with reference to the accompanying drawings in which: Figure 1 is a diagrammatic transverse cross section of a flight vehicle illustrating certain in flight conditions.

Figure 2 is an isometric view of part of a flight vehicle, in this case, a guided weapon, and Figure 3 is a block diagram of an actuating arrange ment.

In Figure 1 a guided weapon has a body 1 with a longitudinal axis X-X about which, in flight it develops a rotation (that is to say a rolling motion); it also develops an acceleration in a plane normal to this axis.

The rotation is denoted by Arrow A and the acceleration is denoted by Arrow B. Conveniently this acceleration is divided into two components, one lying in a plane desig nated C and the other lying in a plane designated D. Both planes include the axis X-X but are at right angles to one another.

Ballast means in the form of a single mass, or as illustrated, in the form of two independently movable masses 2 and 3 are provided within the weapon body 1, the two passes being arranged so that their centres of gravity move, respectively, in the planes C and D. Their means of movement are described with reference to Figures 2 and 3, bat in use they are individually positioned to together balance any out-of-balance movements about the X-X axis resulting fro::a te build of the weapon.Should a rotation A (a roll rate) develop in flight together with an acceleration 3, the masses 2 and 3 are individually moved in their respective planes until a torque opposing the rotation is developed. Additionally, should a rotation -to effect weapon control be desired, the masses 2 and 3 can be moved from a balanced position to initiate such a movement.

Referring now to Figure 2, in which like reference numberals refer to like items to those of Figure 1, the weapon body 1 has housed within it a stabilising and control assembly 4. The assembly comprises two identical units 5 and 6, that referenced 5 being operable in plane C and including the mass 2, and that referenced 6 being operable in plane D and including the mass 3.

In effect the assembly 4 is housed within a transverse "slice" of the weapon body which is of tubular form.

For ease of description only that unit referenced 5 is described in detail, that referenced 6 being, as before stated, identical. The units are mounted back-to-back.

The unit 5 includes a circular plate 7 which is anchored within the weapon body 1. Carried by, but spaced from, the plate 7 is a mounting plate 8 which carries two radius anas 9 and 10 each pivoted (at 11 and 12)respectively, about an axis parallel to the axis -. The radius arms 9 and 10 lie at all times on opposite sides of the plane C and are geared teeter for simultaneous opposite rotation between the one extreme position illustrated \to the right of axis X-X (as drawn) to a further extreme position to the left of axis X-X and vice versa.

Each arm carries an identical weight of 13 and 14, respectively, at its end remote from the pivot. These two weights together form the mass 2 of Figure 1.

Naturally the two equivalent weights of the unit 6 together form the mass 3 of Figure 1.

The weights are of accurate from in transverse cross section so that they conveniently lie within the body at of all angular settings and also lie clear/the remainder of the unit 5.

Rotation of the arms is effected by a gear system 16 and a reversable electric motor 15 carried by the plate 7; the motor protruding through the equivalent plate of the unit 6.

Such rotation causes the effective centre of gravity of the mass 2 (that is to say of the two weights 13 and 1t) to travel to the right or to the left as drawn within the body 1 in the plane C.

Referring now to Figure 3, the ballast means 2 and 3 are diagrammatically illustrated by box 20 and are moved by a motor (including motor 15) diagrammatically illustrated by box 21. A roll rate gyroscope shoam diagrammat-cally at 22 senses the direction and rate of the vehicle rotation and pusses a signal to a summing device 23 which also accepts a signal from a pair of acceleroeters 24 (set at Oo to one another) the signal being a function o the dirction of the accelaration. @@ may also include a function of magnitude.An output signal is then passed through phase advancing means 25 to a power switch 26 which is arranged to supply power to the motor to cause it to effect shifting of the ballast means one way or the other in accordance with the directions of vehicle rotation and acceleration. As before described the effect of such repositioning of the ballast means is to generate a torque opposing the rotation. Should a torque be required to effect vehicle control for example when no rotation is present, then demand signals are applied to move the ballast means to generate a torque to provide a desired rotation.

As illustrated, the control assembly 4 is arranged to provide stabilisation and/or control of a weapon about its roll axis X-X. However the assembly can be used to provide stabilisation and/or control about a pitch or a yaw axis, one assembly being used for each axis0

Claims (8)

CLAIMS WE CLAIM:-

1. Means for aiding the stability and/or control of a flight vehicle which is subject, in flight, both to rotation about an axis and to acceleration normal to that axis including, in combination, movable ballast means housable within the vehicle, sensing means arranged in use to sense the direction of said rotation and the direction of said acceleration, and actuation means responsive to an output of the sensing means to so position the ballast means within the vehicle that a torque opposing said rotation can be generated.

2. Means according to claim 1 wherein the ballast means includes a first mass movable such that its effective centre of gravity moves in a first plane normal to the axis of rotation, and a second mass movable such that its effective centre of gravity moves in a second plane normal to the axis of rotation and normal to the first plane.

5. Means according to claim 2 wherein at least one mass comprises to weights lying at all times one to each side of the plane of movement of the centre of gravity of the mass, a radius arm pivoted at or near the vehicle nazis of rotation carrying each lreight, and means interconnecting the arms for simultaneous o-"osite rotation.

4. Means according to any one of the previous claims T.terein said sensing weans auditionally is arranged to sense the rate of rotation.

5. Means according to any one of the previous claims wherein said sensingmneans additionally is arranged to sense the magnitude of the acceleration.

6. Means according to any one of the previous claims wherein said sensing means includes a rate gyroscope and two accelerometers.

7. A flight vehicle which in flight develops:- both a rotation about an axis and an acceleration normal to that axis, including means for aiding the stability and/or control of the vehicle according to one or more of the previous claims, wherein said means is effective to generate a torque opposing vehicle rotation about one of the pitch, roll or yaw axes.

8. A flight vehicle including control means substantially as described with reference to the accompanying drawings.

8. A method of aiding the stability and/or control of a flight vehicle which is subject, in flight, both to rotation about an axis and to acceleration normal to that axis, including the steps of sensing the direction of the acceleration, to provide an output signal and moving ballast means within the flight vehicle in accordance with the output signal so that a torque opposing the rotation is generated C. Means for aiding stability and/ or control subtantially as described with reference to the accompagnying drawings.

10. A flight vehicle including means for aiding stability and/or control substantially as described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows CLAIMS WE CLAIM:1. Means for controlling a flight: vehicle which is subject, in flight, both to rotation about an axis and to acceleration normal to that axis including, in combination, movable ballast means,'lousable within the vehicle, which include a first mass movable such that ; ts e effective centre of gravity moves in a first plane lecLw We the axis of rotation, and a second mass movable such that its effective centre of gravity moves in a second plane including the axis of rotation and normal to the first plane, sensing means arranged in use to sense the direction of said rotation and the direction of said acceleration, and actuation means responsive to an output of the sensing means to so position the masses of the ballast means within the vehicle that a torque opposing said rotation can be generated.

2. Means according to claim 1 wherein at least one mass comprises two weights lying at all times one to each side of the plane of movement of the effective centre of gravity of the mass, the actuation means including twin radius arms, one carrying each weight, rotatably mounted at or near the vehicle axis of rotation, and means interconnecting the antis for simultaneous opposite rotation.

3. Means according to any one of the previous claims wherein said sensing means additionally is arranged to sense the rate of rotation.

4. Means according to any one of the previous claims wherein said sensing~means additianally is arranged to sense the magnitude of the acceleration.

5. Means according to any one of the previous claims wherein said sensing means includes a rate gyroscope and two accelerometers.

6. A flight vehicle including control means according to one or more of theprevious claims.

7. Control means substantially as described with reference to the accompanying drawings.