US2524793A - Stabilizing apparatus - Google Patents

Description

Oct. 10, 1950 R. F. HAYS, JR 2,524,793

STABILIZING APPARATUS Filed Jan. 15, 1946 Patented Oct. 10, 1950 STABILIZING APPARATUS Robert F. Hays, Jr., Syosset, N. Y., assignor to The Sperry Corporation, a corporation of Delaware Application January 15, 1946, Serial No. 641,382

. Claims.

This invention relates to an apparatus for stabilizing an airborne line of sight defining ap paratus and more particularly to an apparatus for eliminating the error in the line of sight due to roll and pitch of the supporting aircraft.

A feature of the invention is the provision of an apparatus adapted particularly for the stabilization in space of the scanner axis of a radio bomb sight. The invention may be used also to stabilize the line of sight defined by an optical system.

Bomb sights generally comprise a computing mechanism having an output which displaces a line of sight defining device according to the computed sighting angle. Usually the line of sight defining device is a part of the bomb sight and. is stabilized by vertical and directional gyroscopes associated with the bomb sight mechanism. In some applications, particularly where a radar line of sight defining device is used, it is desirable to attach the sighting apparatus directly to the framework of the airplane and to direct the device by remote control from the outto novel features of the instrumentalities described herein for achieving the principal objects of the invention and to novel principles employed in those instrumentalities, whether or not these features and principles are used for the said principal objects or in the said field.

The invention will now be described with the aid of the accompanying drawings, of which Fig. 1 shows schematicall one form of the invention as stabilizing the entrance prism of a periscope, while Figs. 2 and 3 show schematically an arrangement for stabilizing a scanning device of the radar type.

In a preferred embodiment of the invention it is contemplated that the sighting angle be obtained as a shaft rotation from a. suitable bomb sight, not shown, while the azimuth angle may be obtained as a shaft rotation from a directional gyroscope, not shown, which may be the directhe aircraft. The line of sight defining device is supported independentl of the bomb sight, and is positioned in sighting angle by the bomb sight, and in azimuth by the directional gyro scope. The present invention provides further means for adjusting the line of sight defining device according to the sighting angle and in azimuth to compensate for rolling and pitching of the aircraft.

The stabilizing mechanism of the present invention comprises a turntable Ill supported for rotation in azimuth by any suitable means, such as the track H attached to the aircraft. The turntable is positioned in azimuth in accordance with the heading of the aircraft by a shaft l2 controlled by a directional gyro, not shown, the shaft being provided with a worm l3 which meshes with teeth formed in the edge of the turntable.

A bracket l5 attached to the turntable is formed with a pair of upright arms l6 and ll, the latter having horizontal arms l8 and I9 fixed thereto provided with bearings for shafts 2B and 21 attached to gimbal ring 22 of a vertical gyroscope enclosed in casing 23. A spindle 24 secured to the underside of gyro casing 23 in alignment with the spin axis extends through a slot 25 in a bail 26. Opposite ends of the bail are fixed respectively to shafts 21 and 28 which are supported in bearings in arms l6 and I1 at right angles to shafts 20 and 2|.

It will be understood that erecting means of any suitable type, not shown, will be used to maintain the gyroscope erect. The roll axis of the gyroscope coincides with the axes of shafts 21 and 28 which are so disposed as to follow the line of sight in azimuth, while shafts 2G and 2| are disposed along the pitch axis. Since the gyroscope will remain vertical in space, movement of the aircraft in roll and pitch will cause corresponding movement of the shafts 2t and 2| and 21 and 28 in their bearings.

Armature 30 of an E pickoff transformer 3| of conventional type is attached to shaft 2|. Displacement of the aircraft about the pitch axis causes relative movement of the armature and transformer in the known manner, and the transformer, which is energized constantly from a source of alternating current supplies on such displacement, a signal corresponding to the displacement, to the input of a. differential servo amplifier 32 provided with output circuits which control in the known manner a pitch servomotor 33. Servomotor 33 controls a follow-up system which moves pickofi transformer 3| in such direction as to bring the transformer again into register with its armature 39 and thus reduce the output signal therefrom to zero caus ing the motor to stop. The follow-up mechanism is used in conjunction with a sighting angle input to position la. cam arrangement in one dimension, wh ich will be described presently.

An armature 40 of a .pickoff transformer 4| for the roll axis is attached to shaft '28. Movement of the aircraft about the roll axis causes relative displacement of the armature and trans former. The transformer is energized in the known manner from a source of alternating current, and relative displacement of the armature causes a signal corresponding to the displacement to be transmitted from the transformer to a. differential amplifier 42, which, in response to such signal, actuates a servomotor 43' Whichop- I erates a follow-up mechanism in such direction as to bring transformer into register with its armature. This follow-up mechanism cooperates with the azimuth servo shaft to effect relative displacement of the cam arrangement mentioned above, and the lift pins therefor in another dimension, to be described.

Shaft 44, in the present embodiment of the invention is displaced in rotation according to the sighting angle, in the known manner, by a bomb sight not shown. The object of the invention is to stabilize a sighting device controlled by this shaft. Shaft 44 actuates an input shaft for a differential 45 which has a second input shaft 46 fastened to bracket l5 so as to be turned with turntable ID to prevent azimuth rotation from introducing an error into the sighting angle.

three dimension cams 62 and 63 are fixed. The

cams are provided respectively with lift pins 64 and 65 which are mounted for translation with respect to the axis of the cams. The lift pins are supported in bearings at opposite ends of a bar 66 provided on one side with a rack, not shown, which is engaged by the teeth of a gear 61 on a shaft 68 supported in a bearing in a bracket 69. Shaft 68 is turned by the roll servomotor 43. Shaft 68 also drives via gears 10, shaft ll, gears 12, shaft 13, a worm 14 which adjusts the position of pickoff transformer 4| for the roll axis. It will be understood that any suitable means may be used for guiding bar 66 when translated.

Lift pin 64 has a circular rack 80 formed thereon which is in mesh with the teeth of a long pinion 8! on shaft 82 which drives through gears 83 the input shaft 84 of differential 6B. Cam 62, therefore, is effective to displace input shaft 84, and output shaft 6| of the differential is displaced according, to the displacement of the pitch follow-up motor 33 and the displacement of lift pin 64. A gear 85 secured at the lower end of shaft 6i drives a gear 86 fastened to shaft 81 which turns in a bearing in bracket 69. 81, asshown in Fig. 1, displaces through gears 88 a horizontal shaft 89 attached to prism 90 which may be the entrance prism of an optical system.

Lift .pin 65 has a circular rack 9! formed there-;

Shaft on which meshes with the teeth of long pinion 92 fastened to shaft 93which turns in a bearing in bracket 69. Pinion 94 secured to shaft 93 drives a rin gear 95 supported for rotation by turntable II] about a concentric opening therein.

A tubular bracket arrangement 96 in which the horizontal shaft 89 for prism is supported, depends from the ring gear 95. Bracket 96 may be of any convenient shape and may have any necessary openings formed therein in accordance with the requirements of the optical system with which the prism is to be used. An eyepiece 91 of an optical system including the prism 90 is shown diagrammatically in Fig. 1. Equivalent mechanisms are shown in Figs. 2 and 3 for operating a radar scanner.

Bracket 96, together with-prism 90, are turned directly in azimuth by lift pin '65. The displacement-of the lift pin depends on cam 63 which is actuated in rotation by shaft 6|, as already described. The movement of the lift pin axially of the cam depends on the displacement of the roll servomotor 43.

The displacement of shaft 6| depends on the pitch angle of the aircraft as indicatedby the gyroscope, the sighting angle, and the displacement of lift pin 64 by cam 62.

Lift pins 64 and 65 are translated along the axes of the cams in accordance with the roll angle of the aircraft as indicated by the gyroscope. Cams 62 and 63 may be laid out empirically by graphical procedure to effect such displacement of their lift pins as to cause the line of sight to be constantly positioned at the correct angle irrespective of the roll and pitch of the airplane.

In a preferred form of the invention wherein, as mentioned above, the roll axis .of the gyroscope follows the line of sight in azimuth, the corrections required for the sighting and azimuth angles of a radar scanner, or .other line of sight defining device are givenapproximately by the following equations:

sin A13=cot 18s (l-cos and sin Aa=COt 5s sin where Aa=azimuth correction angle to be applied to the scanner;

Afi=sighting angle correction to be applied to the scanner;

=roll indicated by the gyro;

Bs=the angle between the line of sight to the target and the apparent vertical, i. e., a line perpendicular to the floor of the aircraft.

Both sin Ap and sin Ac are equal approximately to cot 3s multiplied respectively by suitable functions of and cams actuated as described above may be laid out to provide output displacements according to Au and A5.

Bracket 96 is shown in Fig. 2 as having a pair of depending arms I02 supporting horizontal shaft 89, which in this figure is shown as carrying a parabola I 93 of a radar line of sight defining device instead of prism 99 of Fig. 1.

The stabilizing arrangement of the present invention ma be used to stabilize a line of sight device by remote control. This feature is advantageous, particularly where a radar scanner is mounted in the wing of a small airplane. Bracket 96 and shaft 81 are outputs for the device and they may be used to position, through any suitable connections a remotely located line of sight defining device. For this purpose; bracket 96, Fig. 1, may be provided with an annular gear I05 which turns a flexible outputshaft .lllllto 5 actuate the arrangement shown in Fig. 3, where shaft I00 is shown as being coupled with a parabola I03 to turn the same about a vertical axis. In Fig. 3, shaft 81 is represented as a flexible shaft for positioning parabola I03 about a horizontal axis.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description r shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In an apparatus for stabilizing the line of sight of a radar antenna carried by an aircraft, a pair of three dimension cams laid out respectively to compute corrections for the position of the aircraft in roll and in pitch, individual lift pins for the cams, means responsive to the roll and pitch of the aircraft for positioning the cams, and means controlled by the lift pins for adjusting the position of the antenna.

2. In an apparatus for stabilizing the line of sight of a radar antenna carried by an aircraft, sighting angle and azimuth position inputs, a computing device comprising a pair of cams laid out to compute corrections for the position of the aircraft in roll and pitch, means responsive to roll and pitch of the aircraft and controlled by said inputs for adjusting the position of the cams, and output means for the cams for adjusting the position of the antenna.

3. An arrangement for. stabilizing the sighting angle of a sight carried by an aircraft comprising a vertical gyro having its roll axis maintained in alignment in azimuth with the line of sight of the sight, a sighting angle input, a device comprising a cam shaft jointly controlled by the sighting angle input and by the gyro according to the displacement of the aircraft about the pitch axis of the gyro for positioning the line of sight according to the sighting angle, cam means for computing pitch correction actuated by the device and an output for the last mentioned means coupled with the device effective to modify the position of the line of sight according to the displacement of the aircraft in pitch.

4. An arrangement for stabilizing the sighting angle of a sight carried by an aircraft comprising a vertical gyro having its roll axis maintained in alignment in azimuth with the line of sight of the sight, a sighting angle input, a shaft, means jointly displacing said shaft by the sighting angle input and by the gyro according to the displacement of the aircraft with respect to the pitch axis of the gyro, a differential having an input displaced by the shaft, an output therefor, a cam laid out to provide pitch correction actuated by the shaft in one dimension, a lift pin for the cam, means for producing relative displacement of the lift pin and cam in another dimension controlled by the gyro according to displacement of the aircraft about the roll axis of the gyro, means controlled by the output of the differential for displacing the line of sight in one dimension and means controlled by the lift pin for actuating a second input of the differential to modify the displacement of the line of sight according to pitch correction.

5. An arrangement for stabilizing the sighting angle of a sight carried by an aircraft comprising a member maintained positioned in azimuth, a vertical gyro supported thereby, a sighting angle input, a differential device having inputs controlled respectively by the sighting angle input and by the gyro according to the displacement of the aircraft in pitch, an output for the differential for displacing the sight according to the sighting angle, pitch correction computing means actuated by the differential output, and an output for the computing means coupled with an input of the differential device for correcting the latter for pitch error.

i 6. An arrangement for stabilizing the sighting angle of a sight carried by an aircraft comprising a member maintained positioned in azimuth, a vertical gyro supported thereby, a sighting angle input, a differential device having inputs controlled respectively by the sighting angle input and by the gyro according to the displacement of the aircraft in pitch, an output for the differential for displacing the sight according to the sighting angle, pitch angle correction computing means actuated by the differential output and by the gyroscope according to the displacement of the aircraft in roll and an output for the computing means coupled with the input of the differential device effective to correct the output of the latter for displacement of the aircraft in pitch.

7. In an apparatus for stabilizing the line of sight of a sight carried by an aircraft, a vertical gyro, a computing device comprising a pair of cam's laid out respectively to compute corrections for pitch and roll error, a lift pin for each cam, sighting angle and azimuth inputs, means controlled by the inputs and by the gyro according to the displacement of the aircraft about one axis thereof for effecting relative displacement of the cams and lift pins in one dimension, means controlled by the gyro according to the displacement of the aircraft about another axis thereof for effecting relative displacement of the cams and lift pins in another dimension, and means adjusted by the respective lift pins for displacing the sight in two dimensions.

8. An apparatus for stabilizing automatically the line of sight of an airborne bomb sight against roll and pitch of a supporting aircraft wherein the line of sight is defined by a sighting device displaced by remote control from a bomb sight computer in accordance with the computed sighting angle and the azimuth angle thereof, said apparatus comprising a turn table, a line of sight defining device supported thereby for relative movement about two axes, one of which is coincident with that of the turntable, an input shaft for adjusting the turntable in accordance with the azimuth angle of the line of sight, a gyro vertical positioned on the turntable with its roll axis disposed along the line of sight in azimuth, a cam shaft, a pair of three dimensional cams fixed thereon laid out respectively to compute corrections for the sighting angle and for the azimuth angle thereof, a lift pin for each cam, means actuated by the gyro in accordance with the displacement of the aircraft about its roll axis for effecting relative displacement in translation of the lift pins and cams, means operated by'the lift pin of one of the cams for effecting relative coaxial movement of the line of sight and turntable, a sighting angle input shaft, means including a plurality of differential devices jointly actuated by the lift pin of the other of the cams, the sighting angle input shaft and the gyro according to the displacement of the aircraft about its pitch axis for turning the cam shaft, and means actuated by .-.the camshaft for displacingthe line of sight defining device about another axis.

9. An apparatus for stabilizing the line of sight of a bombsight against roll and pitch of the supporting aircraft which comprises a turntable, a line of sight defining device supported thereby for relative movement about two axes, a first of which coincides with that of the turntable, an input shaft for turning the turntable according to the azimuth angle of the line of sight, a gyro vertical positioned on the turntable with its roll axis disposed along the line of sight in azimuth, a camshaft mounted on the turntable, a pair of three dimensional cams fixed thereon laid out respectively to compute corrections for the sighting angle and azimuth angle, a lift pin for each cam, means actuated by the gyro according to displacement of the aircraft about its roll axis for effecting relative displacement of the cams and lift pins :in translation, means operated by the lift pin of one of the cams for effecting relative coaxial movement of the line of sight defining device and turntable according to the required correction for the azimuth angle, a sight- ,sight of a bomb sight against roll and pitch of the supporting aircraft which comprises a turn .tablemounted. on the aircraft, a line of sight defining device supported thereby for relative movement about two axes, aninput shaftfor turning the turntable according to the azimuth angle of the line ofsight, a gyro vertical positioned on the turntable so that its roll axis follows the azimuth angle of th line of sight, a cam shaft supported for rotation on the turntable, a pair of three dimensional camsfixed thereto, -a first of the cams being laid out to provide corrections for the sighting angle and the second of the cams being laid out to provide corrections for th azimuth angle thereof, a lift pin for each cam, means actuatedby the gyro according to the displacement of the aircraft about its roll axis for displacing the lift pins in translation with respect tothe cam's, -means operated by-the lift pin of the second of the cams for turning the line of sight defining device about one axis to correct the azimuth angle thereof, a sighting angle inputshaft, means including a plurality of differential devices jointly actuated by the lift pin of the first cam, the sighting angle input shaft and the gyro according to the displacement of the aircraft about its pitch axis for rotatin the cam shaft, and means driven by the cam shaft for adjusting the line of sight about a second axis in accordance with the-sighting angle.

11. An apparatus for stabilizing the line of sight of a bomb sight against roll and .pitch of the supporting aircraft which comprises a turntable mounted on the aircraft, a line of sight defining device supported thereby for relative movement about two axes, one of which coincides with that of the turntable, an input shaft for turning the turntable according to thecomputed iazimuth angle of the line of sight, a gyro vertical fixed to theturntable withits roll axis disposed in the vertical plane which includes the line of sight in azimuth, a cam shaft mounted on the turntable, a pair of three dimensional cams fixed thereto, a first of the cams being laid-out to compute corrections for the sighting angle and the second cam being laid out to provide corrections for the azimuth angle thereof, a lift .pin for each cam, means actuated by the gyro according to the displacement of the aircraft about the roll axis thereof for translating the lift pins along the surfaces of the cams, means including shafts and gearing actuated by the lift pin of the second cam for adjusting the angular position of the sighting device about the axis coincident with that of the-turntable. to correct the azimuth angle thereof, a sighting angle input shaft, means including a plurality of differential mechanisms operated jointly by the lift pin of the first cam, the sighting angle input shaft and the gyro in accordance with the displacement of the aircraft about the pitch axis thereof for turning the cam shaft, and means comprising shafts and gears coupling the cam shaft with the sighting device for adjusting the angular position thereof about a second axis according to the sighting angle.

12. An apparatus for stabilizing automatically the line of sight of an airborne bomb sight antenna against roll and pitch of a supporting aircraft wherein the antenna is positioned angularly about two intersecting axes by remote control from a bomb sight computer in accordance with a computed sighting angle and the azimuth thereof, said apparatus comprising a turntable, an input shaft for rotating the turntable in accordance with the azimuth angle of the line of sight, a gyro vertical mounted on the turntable with its roll axis disposed along the line of sight in azimuth, a cam shaft, a pair of three dimensional cams thereon laid out respectively to compute corrections for the sighting angle and the azimuth angle thereof, a lift pin for each cam, means actuated by the gyro in accordance with the displacement of the aircraft about the roll axis thereof for effecting relative displacement in translation of the lift pins and cams, means operated by the lift pin of the one of the cams for adjusting the angular position of the antenna about one of its axes, a sighting angle input shaft, means including a plurality of cooperating differential mechanisms jointly actuated by the lift pin of the other of the cams, the sighting angle input shaft and the gyro in accordance with the displacement of the aircraft about the pitch axis thereof for turning the cam shaft, and means driven from the cam shaft for adjusting the angular position of the antenna about the other of its axes.

13. An apparatus for stabilizing automatically the line of sight of an airborne radar antenna of the kind which is movable about two intersecting axes under control of a remote computer in accordance with a computed sighting angle and the azimuth angle thereof, which comprises a turntable mounted on the supporting aircraft, a gyro vertical supported, thereby, an input shaft for turning the turntable to cause the roll axis of the gyro to follow the line of sight in azimuth, a cam shaft mounted on-the turntable, a pair of three dimensional cams fixed thereon laid out respectively to compute corrections for the sighting angle and azimuth angle to compensate for roll and pitch of the supporting aircraft, a lift pin for each cam, means actuated by the gyro in accordance with the displacement of the aircraft about the roll axis thereof for effecting relative displacement of the cams and lift pinsin translation, means operated by the lift pin of one of the cams for effecting displacement of the antenna about one of its axes in accordance with the corrected azimuth angle, a sighting angle input shaft, means including a plurality of cooperating differential devices jointly actuated by the lift pin of the other of the cams, the sighting angle input shaft and the gyro in accordance with the displacement of the aircraft about the pitch axis thereof for turning the cam shaft, and means actuated by the cam shaft for displacing the antenna about the other of its axes in accordance with the corrected sighting angle.

14. In an apparatus for stabilizing a radar antenna mounted on an aircraft against roll and pitch, the antenna being of the kind adapted for operation by remote control from a computer which displaces the antenna about two intersecting axes respectively in accordance with a computed sighting angle and the azimuth angle thereof, the improvement which comprises a turntable mounted on the supporting aircraft, a gyro vertical supported on the turntable, an input shaft for turning the turntable to keep the roll axis of the gyro in alignment with the line of sight in azimuth, a radar antenna mounted for movement about two axes on the under side of the turntable, one of the axes being coincident with that of the turntable, a cam shaft mounted on the turntable, a pair of three dimensional cams fixed thereto, a first cam being laid out to compute c0rrections for the azimuth angle of the line of sight, the second cam being laid out to compute corrections for the sighting angle, a lift pin for each cam, means actuated by the gyro in accordance with the displacement of the aircraft about the roll axis thereof for effecting relative displacement of the cams and lift pins in trans lation, means operated by the lift pin of the first of the cams for effecting relative displacement of the antenna and turntable in accordance with the corrected azimuth angle, a sighting angle input shaft, means including a plurality of cooperating differential devices'jointly actuated by the lift pin of the second of the cams, the sighting angle input shaft, and the gyro in accordance with the displacement of the aircraft about the pitch axis thereof for turning the cam shaft, and means actuated by the cam shaft for displacing the antenna about the other of its axes in accordance with the corrected sighting angle.

15. In an apparatus for stabilizing a radar antenna mounted on an aircraft against roll and pitch, wherein the antenna is of the type used in conjuction with a remotely located bomb sight computer which displaces the antenna about two intersecting axes in accordance with the sighting angle and the azimuth angle thereof respectively, the improvement which comprises a turntable mounted on the supporting aircraft, a gyro vertical supported on the turntable, an input shaft for turning the turntable to maintain the roll axis of the gyro in alignment with the sighting angle in azimuth, a radar antenna mounted on the under side of the turntable for movement about two intersecting axes one of which coincides with that of the turntable and the other being disposed at right angles thereto, a cam shaft mounted on the turntable, a pair of three dimensional cams fixed thereto, a first of the cams being laid out to compute corrections for the azimuth angle of the line of sight, the second cam being laid out to compute corrections for the sightin angle, a lift pin for each cam, means actuated by the gyro in accordance with the displacement of the aircraft about the roll axis thereof for translating both cam pins along the surfaces of the cams, means operated by the lift pin of the first of the cams for effecting relative displacement of the antenna with respect to the turntable about their coincident axes in accordance with the corrected azimuth angle, a sighting angle input shaft, means including a plurality of cooperating differential mechanisms jointly actuated by the lift pin of the second cam, the sighting angle input shaft, and the gyro in accordance with the displacement of the aircraft about the pitch axis thereof for turning the cam shaft, and means actuated by the cam shaft for displacing the antenna about the other of its axes in accordance with the corrected sighting angle.

ROBERT F. HAYS, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,733,531 Dugan Oct. 29, 1929 1,937,336 Ford et a1 Nov. 28, 1933 2,371,606 Chafee et a1 Mar. 20, 1945 2,407,275 Hays Sept. 10, 1946 2,415,680 Hoyt Feb. 11, 1947

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