US2383409A

US2383409A - Controlling means for gyroscopes

Info

Publication number: US2383409A
Application number: US490866A
Authority: US
Inventors: William H Newell
Original assignee: Ford Instrument Co Inc
Current assignee: Ford Instrument Co Inc
Priority date: 1943-06-15
Filing date: 1943-06-15
Publication date: 1945-08-21
Anticipated expiration: 1962-08-21

Description

ug.'21, 1945. w. H. NEWELL CONTROLLING MEANS FOR GYROSCOPES Filed June l5, 1945 2 SheecS-Sheeb l j 5; mvENToR \N\LL1AM HNEWELL /ATTORNEY Ag 21, 1945 w. H. NEwELL 27,383,409

I CNTROLLING MEANS FOR GYROSCOPES Filed June i5, 1943 2 she@US-shea 2 illlHH'IIIIIIIIIIIIIllllllllllllllllllllllhlllllllllIIIIIIIIIHIIIIIIHIIIIIIHIHIIIIHH? INVENTOR WxLLlAM H. NEWELL.

ATTORNEY l Patented Aug. 2l, l5

2,383,409 .CONTROG MEANS FOR GYROSCOPES William H. Newell, New York, N. VFord Instrument Company,

Y., assignor tol Inc., Long Island City, N. Y., a corporationfof New York Application June 15, 1943, Serial No. 490,866

s claims. fm. 'x4-5)' e In the case offollow-up mechanisms with gyro.

scopes where power means operate to cause a member to follow the movement of the 'spin axis ofthe gyroscope, the power means Vbeing under the `ioint control oi' the .follower member and the gyroscope, it occurs in some constructions that when the speed of precession of the gyroscope A exceeds the possible speed of the follower member, the joint control elements operate physically to limit the positional disagreement between the gyrosccpe and the follower member, and to impose a reactive force upon the gyroscope when the disagreement becomes excessive, which force imposes a couple around the axisin respect to which the disagreement occurs. This couple causes erroneous precession of the gyroscope about its other precession axis'. Such irregular perfomance of a Vgyroscope is known as tumbling, and it isrto means for correcting for such mishap that this invention relates. Y

The invention is useful and will be explained in association with a gyroscope mounted to have is capable of being directed at a moving object and to follow the object in space. Forces are applied 'as couples around the respective precession'axes proportional tothe respective rates of three degrees Vof freedom, the spin axis of which precession required to cause the spin axis to follow the movement of the object. HSuch a gyroscope is usually referred to as an angle gyro.

A Vcommon use for angle gyros Yis in directors l for anti-aircraft gun fireV control mechanism, in

whichthey function to maintain the sighting device on the target. The relative movement oi Y thetarget has both an elevation and a train component, Yand the follower member,v which may be the support for the sighting device, must therefore'have imparted to it a; movement thatis the resultant of those two components in order to stay on the target. In other words, in anti-aircraft gunnery the line of observation is usually in an in a horizontal plane in order to follow the precession of the gyroscope inthe inclined plane of its spin axis, exceeds the rate of precession, and the ratio between the two rates is the cosine of Y the angle of elevation. In'other words, designating the 'rate of train in the horizontal as dBa and the rate of precession of the gyroscope, that is, the rate of train in the inclined plane of sight as dBN, and the angle of elevation, that is,Y the angle which the line of sight makes with the horizontal, .as A, v v

dBN

cos AgdBH Therefore .at an elevation of o0 the vrate oi' train in the horimntal must be twice the preceesion rate oi the gyroscope in train, and approaches an inilnite rate at.90 elevation.V VAt some angle of elevation, therefore, the rate oi' precession may exceed the capability oi the train- Ving motor to i'ollow, with the result that thev gyroscope will try to get ahead of the follower member.. It this causes the contact or other control element that is moved with the gyroscope to jam, there is a reaction upon the gyroscope which causes itl to precess in elevation and thus lose the target. Y

In accordance with this invention means come into action before this point isi-cached to reduce the precession force that is causing the gyroscope to process in train so as to limit the precession rate to that at whichthe motor can train the follower member in the horizontal. Thus'itmay happen at high elevations that a training rate will be calledfor in order to follow the target which will exceed the capability of the training inclined plane, but the vrate of training is com- A monly related to the horizontal plane. 'I'his is because the training rack about which the sighting device trains is disposed in the horizontal if on land, or in the plane of the deck Aof a ship if on ship board.`

The power motors for the follow-up mechanism are of any 'suitable type.' such as electric or hydraulic, and it is necessary for. each to keep up with its component of movement of the gyroscope in order to keep the sighting device directed atthetarget. As the elevated target, such as anY airplane, moves in a direction that involves a train component, the me or training of me eighties motor, with the result that the l-irecession rate of the gyroscope willv have to be limited and the sight cannot be moved in train fast enough to keep on the target. However in this 4way there is avoided the development oi a false elevation rate in the movement of the sight, in other words, the

l fgyroscope is not caused to tumble.

Y motor is energized to subtract from the torque,

specifically. m the construction shown, there is provided a supplemental motor connected to act upon the mechanism that applies the torque around the elevation 'axis to effect precession of the gyroscope in train, and ,when at full motor speed the las of the follower member in train exceeds a certain amount, the supplemental causing p recession of the gyroscope in train and so reduce the precession rate to thatA commensurate with the training rate.

TQ agot.' the training motor the requisite ollportunity for speed adjustments, one of the joint control members is made yieldable against a centering spring so as to absorb a limited amount of lag in following, and the arrangement of the cc-ntrol for the supplemental motor is such that the supplemental motor does not become energized until the error exceeds a substantial but predetermined amount.

This safeguard is shown as applied only t the precession rate in train, but it will be obvious that it can be as well applied to limit the elevation rate of precession. However for the use herein contemplated the same problem does not arise in following a target in elevation.

The illustrated embodiment of the invention will now be described and thereafter the invention will be pointed out in claims.

Fig. l is a perspectiva'partly in section, of an apparatus embodying the invention.

Fig. 2 is an end view of the same.'

The gyroscope and its associated parts are shown mounted upona training table I arranged to turn in a fixed circular rack 2. Hung on journals 3 in uprights 4 on `the table i is a cradle 5 which constitutes the follower member and is in eilect an open, four sided frame having a top 6,' sides 1 and a bottom 8. A training electric motor 9 trains the table I and hence the cradle 5, and an elevation electric motor I0 controls the angular disposition of the cradle on its trunnions, that is, its elevation. The train motor 9 is supported by a bracket from one of the uprights t and is connected by gears II, I2, I3, I4 and l5 to the training rack 2. A bracket I6 on the training table supports the bearings for the gears i2, I3 and I4, I5. Thus the turning of the motor 9 will cause the bracket I6 and hence the table to turn in the rack.

The rocking of the cradle on its journals to move it in elevation is similarly eiected by the motor I0 through gearing and a flxed rack. As shown, an arcuate rack is fastened to the upright 4 opposite the one on which the motor 9 is mounted, and a pinion I1 on the motor shaft, which turns in a bearing on the adjacent side member 1, engages the teeth on the rack. Thus the turning of the motor will rock the cradle.

A gyroscope I8 is pivoted on horizontal 'trunnions I9 in a sensitive ring 29 that is pivoted on vertical trunnions 2| in the top and

bottom members

6 and 8 of the cradle. The end of the upper trunnion 2I where it projects through the top member 6 of the cradle, has fastened on it an arm 22 that carries a primary contact member 23, cooperative with the contacts of a double secondary contact member 24 pivoted in a bearing on a bracket 25 carried on the top member 8. These primary and secondary contacts are connected through a source of current to the motor 9, as shown, so that the motor is reversely energized by the engagement of the primary contact with one or the other of the double contacts. So the relative movement of the gyroscope and cradle in train energizes the train motor 9 and trains the cradle to follow the gyroscope.

Similarly the relative movement of the gyroscope and cradle in elevation will energize the motor I9. A vertically disposed arm 28 is pivoted on a horizontal axis to the cradle, and at its lower end carries a primary contact 21 that cooperates with the double contacts of a secondary contact member 28, pivotally carried by a bracket arm 29 attached to the bottom member 8. These primary and secondary contacts are connected through a source of current to the motor I0, as shown, s'o that the motor is revereely energized by the engagement of Ithe primary contact with one or the other of the secondary contacts. The upper end of the arm 28, at a point above the pivot, is connected to the gyroscope I8 vertically above its spin axis at a point midway between the horizontal trunnions I9, by arms 30 that have torques around the respective axes of the gyro' scope. The one` for adjusting the torque around the vertical axi and so produce precession about the horizontal axis is shown at the bottom and is operated in the form shown by a knob 3l. A bell-crank 32 is pivoted on a horizontal slide 33, and has a roller 36 that is urged against the face of a foot-piece 35 of the sensitive ring 20 by a spring 36 connected at one end to the arm of the bell-crank 32 and at the other end to a pin on the slide 33. At either side of the center line the roller applies a torque about the axis 2I2 I, the moment of which depends upon the displacement of the roller from the center. The knob 3| is operatively connected to the rack 33 by bevel gears 31 and pinion 38 that engages the rack teeth on the slide 33. Therefore in order to cause the spin axis of the gyroscope to precess in elevation, the operator turns the knob 3| and offsets the roller 34 an amount depending upon the desired precession rate.

Similarly the operator turns a knob 39 to cause the gyroscope to precess in train. The spindle of the knob turns in a support 40 on the bottom member 8 and has on its opposite end a pinion 4I that engages with the rack on a vertical slide 42. A I`bell-crank 48 pivoted on the slide, like bell-crank 32, has a roller on one end and its other end attached to a spring fastened to a pin on the slide. Thus the roller is urged out' wardly. and it bears against the edge of the arm 26. When it is opposite the pivot the torque impressedy by it is zero, and when it is above and below the pivot it impresses a torque proportional to the displacement from the pivot. This push or pull on the arms 30 applies a couple around the axis I9-I19 which causes a precession about the axis 2I-2I.

As above stated, both the double

secondary contacts

24 and 28 are pivotally mounted. Centering springs 44 bias the contact member 24 to a position where the primary contact 23 is midway between the two secondary contacts when the gyroscope and its follower member are in positional agreement in train. Similarly centering springs 45 center the secondary contact member 29 with respect to the primary contact 21. In both instances the centering springs permit the secondary contacts to yield somewhat and absorb some error before the supplemental motor contacts are engaged, as will presently be described. In this way the motors 9 and I0 will have time to get up to full speed before the supplemental motor can act.

Means are provided to limit the accelerations of the motors.- Motor 9 is also connected through

gears

46, 41 and 48 and the connecting shafts with one side of a differential 49. The other side of the differential is connected to an inertia member 50, while the center of the differential is con'- nected to one of the members of a viscous drag of the table I will bemore for a given rate of element |.v The other member of the drag element is fastened on a shaft that bears in the bracket 25 and has a bevel gear 52 on its other end. The gear 52 meshes with bevel gear 58 on the stub shaft that is secured to the secondary contact member 24 and is the pivot that bears in the bracket 25.

Thus it will be seen that the rate of accelera.- tion and deceleration is limited. When the motor 9 starts and before the inertia. member 50 gets up to speed, the center of the differential turns and the drag member is operated and tends to turn the contact member 2l on its pivot in a direction to open the contacts and so limit the -acceleration of the motor. When the inertia member gets up to speed the drag element is not rotated and the centering springs M yield against the pressure of center contact member 24. When the motor 9 slows down the inertia member 50- gets ahead and rotates the drag element in the direction to tend to close the contacts and so prevent the motor from slowing down too fast.

There are similar means to limit the acceleration of motor lll. The amature shaft of motor I0 connects to one side of a differential 54 through pinion 55 on the motor shaft and gear 56 the shaft of which is connected with one side of the differential 54V and bears in adjacent side piece 1 of the cradle and in a bracket arm 51 opposing and like bracket arm29. The other side of the differential 54 is connected to an inertia member 58, while the center of the differential is connected to one member of a drag train about the axis 2|-2l as the elevation increases. Thus there is a condition approached in which the maximum speed of the motor V9 is insuiiicient to keep the cradle 5 up with the gyroscope in train. As the lag develops, first the springs 44 yield until contact 6 3 engages one' or the other of contacts 62. This energizes rthe torque motor 60 and causes it to apply a counter torque on the arm 26 and so diminish 4the couple around the axis I9-|9. Thus the precession rate of the gyroscope in train is brought down yto that of 'the follower member.

porting member for freedom of precession about' K 'two mutually perpendicular axes, means for applying controlled precession forces' to the gyroelement 59. The other member'of the drag element yis connected to the pivot shaft of the secondary contact member 28.

So long as the speed of precession of the gyroscope is within lthe speed range of the follow-up motors. the centering springs M and will prevent a back pressure trom developing on the primary contacts moved by the gyroscope which will cause the gyroscope to tumble. Since, for the reason stated, the inability to follow is likely to occur in train at the higher altitudes, anti-tumbling means are vshown only in connection with the means to cause precession in train. Obviously, if desired. similar preventive means may be applied to the means for-causing precession in elevation.

In the form shown an anti-tumbler 'electrick motor is employed. This is mounted on an extension of the top Bof the cradle and has on its scope about each of said precession axes, power means for moving the supporting member about its axes, controls for the power means responsive to the4 relative angular positions of the gyroscope and its supporting member, and additional means responsive to predetermined relative angular positions for applying a force opposing said precession force.

40 supporting member Vfor freedom of precession shaft a crank 5l the pin of which engages ina slot in the top end of the pivoted arm 28.- The motor therefore acts as a-torque motor to exert a torque one way or the other upon the arm 26.

Motor 60 is controlled by contacts operated by the relative movement of the gyroscope and cradle in train, and spacedy so -as to engage only after an appreciable lag has developed, that is, after the centering springs 44 have yielded to the point where further pressure of the center v' contact 23 will react upon the cause it to tumble.

As shown, two spaced secondary contacts -52 gyroscope and are carried by the follower member 5, and an intermediate primary contact 63 is carried by the sensitive ring 20 of the gyroscope. l'Ihese contacts are connected to the motor 60 through a source of current, as is shown.

`about two mutually perpendicular axes, means for applying controlled precession forces to the gyroscope about each of said precession axes, a separate power means for moving the supporting member about each of its axes, controls foreach f power means including two cooperative elements` one of which is movable by the gyroscope and the other by the supporting member, and means responsive to predetermined relative movement of said controlelements to modify said precessionA forcesf 3. Controlling means for gyroscopes comprising` in `combination with a supporting member pivoted for .movement about two mutually perpendicular axes and a gyroscope mounted inthe supporting member for freedom of precession about two mutually perpendicular axes,` precession means for applying controlled precession forces to the gyroscope about each yof said precession axes, a separate power means for moving 'the supporting member about each of-its axes,

controls for each power means including two contactable elements one of which is movable by the gyroscope and the other by the supporting member, said elements being so mounted that pressure of the one element against the other reacts upon the gyroscope'as a precession force,

an additional power device operative uponone of g said precession means, anda control for the ad- It is now apparent that in order to keep the sight on the target in train. the operator turns the knob 39 to obtain the desired rate of train about the axis 2 l-2l, and that the rate of train ditional power device including two cooperative elements one of which is movable by the gyroscope and the other by the supporting member.

4. Controlling means for gyroscopes comprising, in combination with a supporting member pivoted for movement about two mutually perpendicular axes and a gyroscope mounted in the supporting member for freedom of precession about two mutually perpendicular axes, meansior applying lcontrolled precession forces to the gyroscope about each of said precession axes, two electric motors operative to move the supporting member about its respective axes, energizing means for each motor including a pair of relatively movable contacts one moved by the gyroscope and the other by the supporting member, one of the contacts being yieldable and having resilient means to bias it to a predetermined relative position, an additional electric motor operative upon one oi.' the means for applying a precession force, and energizing means for the additiona1 motor including apair of contacts operative respectively by the gyroscope and the supporting member and adapted to engage after engagement of the contacts controlling the motor moving the supporting member.

5. Controlling means for angle gyroscopes comprising, in combination with a supporting member mounted for movement about train and elevation axes and a gyroscope mounted in the supporting member for freedom of precession about train and elevation axes, independent adjustable means for applying a couple around each precession axis, a motor for moving the supporting member about its train axis, a separate motor for moving the supporting member about its elevation axis, means for activating each motor including two cooperative elements one movable by the gyroscope and one by the supporting member, a torque motor operative to modify the couple applied around the elevation axis, and means for activating the torque motor including an element carried by the gyroscope and an element carried by the supporting member, the two elements being cooperative upon relative movement of the gyroscope and supporting member about their train axes.

6. Controlling means for angle gyroscopes comprising, in combination with a supporting member mounted i'or movement about train and elevation axes and a gyroscope mounted in the supporting member for freedom of precession about train and elevation axes, independent adjustable means for applying a couple around each axis, an electric motor for moving the supporting member about .its train axis, a separate electric motor for moving the supporting member about its elevation axis, means for energizing each motor including a pair of relatively movable contacts one movable by the gyroscope and the other by the supporting member, an electric motor having a torque applying connection with the means for applying a couple around the elevation axis of the gyroscope, and means for energizing the torque applying motor including two contact elements one carried by the gyroscope and one by the supporting member in position to cooperate as a result of relative movement of the gyroscope and supporting member about their train axes.

7. Controlling means for angle gyroscopes comprising, in combination with a supporting member mounted for movement about train and elevation axes and a gyroscope mounted in the supporting member for freedom of precession about train and elevation-axes, independent adjustable means for applying a couple around each axis, an electric motor for moving the supporting member about its train axis, a separate electric motor for moving n the supporting member about its elevation axis, means for energizing each motor including a pair'of relatively movable contacts one movable by the gyroscope and the other by the Supporting member, one of the contacts being yieldable and having resilient means to bias it to a predetermined positional relation to the part by whichit is (moved, an electric motor having a torque applying connection with the means for applying a couple around the elevation axis of the gyroscope, and means for energizing the torque applying motor including two contact elements one carried by the gyroscope and one by the supporting member in position to cooperate as the result oi' relative movement of the gyroscope and lsupporting member about their train axes.

8. Controlling means for angle gyroscopes comprising, in combination with a supporting member mounted i'or movement about train and elevation axes and a gyroscope mounted in the supporting member for freedom of precession about train and elevation axes, independent adjustable means for applying a, couple around each axis, an electric motor for moving the supporting member about its train axis, a separate electric motor for moving the supporting'member about its elevation axis, means for energizing each motor including a pair of relatively movable contacts one movable by the gyroscope and the other by the supporting member, the contact moved by the supporting member being resiliently mounted on the member so as to yield under pressure of the cooperating contact, an electric motor having a torque applying connection with the means for applying a couple around the elevation axis of the gyroscope, and means for energizing the torque applying motor including two contact elements one Acarried by the gyroscope and one by the supporting member in position to cooperate as the result of relative movement of the gyroscope and supporting member about their train axes, the last mentioned contacts being mounted so as to engage after the contacts controlling the train motor have engaged and when the yieldable contact is moved from its biased position.