US2938486A - Torpedo depth control system - Google Patents

Description

May 31, 1960 s. KOWALYSHYN ETAI- 2,938,436

TORPEDO DEPTH CONTROL SYSTEM Filed Jan. 19, 1954 2 Sheets-Sheet 1 l2 SEA PRESSURE n \1 l5 l6 l3 6 l6 g I? Q: '8 6 4 4 j g as 23 g as & g ///r i 4/ l-m E v '4 3a SERVO AMP.

DEPTH RATE INVENTORS.

STEPHEN KOWALYSHYN THOMAS A. DALY LEONARD S. JONES WILLIAM O. OSBON CHARLE8 O. BEATTY u/ wrw 2622M ATTORNEYS 2 Sheets-Sheet 2 May 31, 1960 s. KOWALYSHYN ET AL TORPEDO DEPTH CONTROL SYSTEM Filed Jan. 19, 1954 TORPEDO DEPTH CONTROL SYSTEM Stephen Kowalyshyn, Sharon, Thomas A. Daly, Swarthm ore, Leonard S. Jones, Sharon, and William O. Osbon, Pittsburgh, Pa., and Charles G. Beatty, Arcadia, Calif., assignors, by mesne assignments, to the United Statesof America as represented by the Secretary of the Navy Filed Jan. 19, 1954, Ser. No. 405,058

7 Claims. (Cl. 114-25) The present invention relates to torpedo depth control systems, and has more particular reference to such control systems having anticipating depth control charactenstics.

Stable control in depth of present day torpedoes is commonly achieved by introducing into the control systems, in addition to a depth component corresponding to deviation of torpedo depth from set depth (desired running depth), an anticipation component corresponding to the speed at which the torpedo is approaching or departing from set depth. Prior depth control systems of the above type have generally employed a hydrostat for depth determination and a pitch-angle-indicating pendulum for providing the anticipation component. Such a pendulum arrangement, however, has the inherent disadvantage of being responsive to all acceleration forces With the result that it does not provide a reliable anticipation component. L

The present invention avoids the disadvantages associated with these prior depth control systems by providing means for directly obtaining the rate of change of torpedo depth irrespective of the acceleration forces to which the torpedo is subjected. For example, the rate of change of depthis measured, in one form of the present invention, by the relative displacement of a hydrostat-operated shaft damped with an attached dashpot Whose reaction force on the shaft is proportional to the velocity of the shaft. Synchros, energized from the torpedo power supply, are utilized to convert the movements of the depth and depth rate hydrostat shafts into electrical signals indicative of the depth error and the rate of change of depth, and are introduced into the depth channel of a servo amplifier to actuate the torpedo depth control surfaces in accordance with the electrical sum of the signals to thus bring the torpedo to the desired running depth with minimum hunting thereabout.

In accordance with'th'e foregoing, it is an object of the present invention to provide a torpedo depth control system having anticipating depth control characteristics.

Another object of the invention is to provide a torpedo depth control system as in the foregoing which is insensitive 1 to the various extraneous accelerationsto which'the torpedo may be subjected.

. A further object of the invention is to providega torpedo dept h control system having anticipating depth control characteristics.wherein the anticipation. component depth. V p Still a further object of the invention is to provide a torpedo depth control system, having anticipating depth control characteristics, which is simplein construction, which re quires a minimum of precision in its manufacis derived directly from therate of'change of torpedo :ture,"'whi'ch necessitates simple and relatively few adjustments for proper operation, and which is comprised of essentially similar components. 7 c Another object of the .invention is to provide an accurate and reliable torpedo depth control system having 7 i members "ice anticipating depth control characteristics, as in the foregoing, wherein depth and depth rate components are derived from an undamped hydrostat and a clamped bydrostat, the movements of which are utilized to operate electrical syncho means in a manner to produce an elec-- trical signal which is a function of depth error (displacement from a desired depth) and rate of change of tailed description had in conjunction with the annexed drawings wherein:

Fig. 1 illustrates in diagrammatic form one arrange ment of the present invention;

Fig. 2 schematically illustrates a depth control circuit employing the hydrostat and synchro assembly shown in Fig. l; 1 a

Fig. 3 schematically illustrates a modified arrangement for converting the movements of the hydrostat shafts into servo amplifier control signals;

Fig. 4 illustrates in schematic form a modified arrangement of the damping means of the present invention; and

Fig. 5 illustrates a modified arrangement for drivably' connecting the synchro shaft and hydrostat shaft.

Referring now to the drawings, more particularly to the modification of Fig. 1, there is illustrated a hydrostat assembly 10 comprising a chamber 11 communi cated to sea pressure through an inlet port 12 and coinmunicated with a first hydrostat chamber 13 through openings 14 having formed therearound a valve seat 15. Hydrostat chamber 13 is communicated with a second hydrostat chamber 16 by an opening 16'. Disposed in the hydrostat chambers '13 and 16 are hydrostat bel' lows, 17 and 18 respectively, each of said bellows being sealed at its lower end to the bottom walls of the hydrostat chambers. Secured to the end walls of the bellows 17 and 18 are operating shafts, 19 and 20 respectively, operating shaft 19 being extended at its upper end, as shown, and having attached thereon a valve member 21 for sealingly engaging valve seat 15 under conditions hereinafter described. Disposed within the hydrostat bellows 17 and 18 are compression springs, 22 and 23 respectively, the springs abutting the end walls of the bellows at their upper ends andvcon'tacting members 24, 25, respectively, at their lower ends, said being adjustably secured within openings formed in the lower end walls of chambers 13 and 1 6, as by threading, whereby toadjust the compression ,of springs 22 and 23. Shafts 19 and 20 have formedon their lower ends teeth constituting racks 19 and 20-, Bellows 17 and its associated elements comprise what may be termed the depth rate hydrostat, while bellows 18 and its associated elements comprise the depth hydrostat. It is to be understood that the depth ratehyd-rostat is basically a depth hydrostat which, however, by means of damping as. later described, lags in its response to depth changes and displaces at a rate corresponding to the rate of change of depth.

A first synchro, broadly designated as 26 and comprising a stator 27 and a rotor 28, is adapted to be operated in a manner to produce an output signal which is propor- Patented May 31, 1960;

3 tional to the rate of change of torpedo depth. To this end, synchro stator 27 is drivably engaged with rack 19. as by means of a drive shaft 29 and a gear 30, while rotor 28 of synchro 26 is drivably engaged with the rack 20' as by means of a drive shaft 31 and a gear 32, whereby the differential rotation between stator 27 and rotor 28 will be determined by the differential movement of hydrostat shafts 19 and 20. Shaft 19 of the depth rate hydrostat bellows 17 is connected, as by means of a link 33, to the plunger 34 of a dashpot assembly 35. Dashpot assembly 35, which may comprise any conventional dashpot assembly, is shown for purposes of illustration only, as a chamber 36 having its opposite ends communicated as by a conduit 37 in which is placed an adjustable orifice valve 38. Chamber 36 and conduit 37 are, in the conventional manner, filled with a suitable damping fluid, the arrangement being such that the reaction force on plunger 34 is proportional to the velocity of the plunger in chamber 36.

A second synchro 39, which is adapted to provide an output signal that is a function of depth, comprises a rotor 40 and stator 41. Rotor 40 is drivably engaged with the rack 20 as by means of a drive shaft 42 and a gear segment 43,while stator 41 of synchro 39 is fixed to some portion of the torpedo body structure 44, whereby the differential rotation of rotor 40 and stator 41 will be determined by the movement of shaft 20 of depth hydrostat bellows 18.

Referring now to Fig. 2 wherein there is illustrated in schematic form a depth control circuit employing the hydrostat and synchro assembly shown in Fig. 1, there is provided within the torpedo a voltage source 45 which is electrically connected to the rotor 40 of depth synchro 39. This synchro, which may be a synchro generator, may have its stator leads electrically connected to the stator of a synchro differential generator 47, the latter'having its rotor leads connected to the stator of depth rate synchro 2-6, which may be a synchro control transformer. The output from the rotor of synchro transformer 26 is fed into a servo amplifier and actuator 49 to control the torpedo depth control surfaces in accordance with the signals fed thereto.

The operation of the present depth control system is as follows: Upon entrance of the torpedo intothe water, sea pressure will be exerted on hydrostat bellows 17 and 18 by water flowing through inlet port 12, and openings 14 into chamber 13 and into chamber 16 through opening 16'. The'compression of bellows 18, and hence the inment of torpedo depth from set depth, such set depth a being fixed by angular adjustment of either stator 46, or

rotor 48 as shown, of differential synchro generator 47. The output signal from differential synchro generator 47 is modified according to the relative angular displacement of stator 27 and rotor 28 of synchro control transformer 26, which as previously stated, is a function of the rate of change of torpedo depth, whereby the electrical signal fed into: servo amplifier 49 for actuating the torpedo con: trol sunfaces will correspond to a summation of torpedo depth error and rate of change of torpedo depth.

Differential synchro generator 47 in association with the illustrated hydrostat'and synchro assembly provides a convenient system for automatic steering and depth setting, for by well-known and conventional techniques, not shown, it may be remotely controlled before torpedo launching, or additionally during a torpedo run, to preselect a set depth (normal torpedo running depth) during target search, or to provide for scheduled control of steering in depth during target search, or automatic steering in depth during homing attack. Should it be desired, however, merely to preselect a set depth, this may be effected by for rotational adjustment of stator 41 of synchro 39 whereby to accomplish manual depth setting, and

differential synchro generator 47 may thus be omitted and the output of depth synchro 3-9 fed directly into rate synchro26.

. The spring constant of bellows assembly 17 and the relative positions of valve seat 15 and valve member 21 are made such that upon the torpedo exceeding a predetermined depth, valve member 21 will move into sealing engagement with valve seat 15 whereby to prevent the application of excessive pressures to bellows 17 and 18 and thus prevent damagethereto.

stantaneous displacement of shaft 20 from its normal of stator 27 and rotor 28 of synchro 26 will be dependent upon the instantaneous differential displacementof ' hydrostat shafts 19 and 20. It will be apparent that the instantaneous difierential displacement of shafts 19 and 20 will be a function of the damping force exerted on shaft 19 by dashpot assembly 35, which damping force acts to oppose movement of shaft 19, and hence such damping force is a function of the rate of change of pressure acting on bellows 17, or, in other words, a function of the rate of change of torpedo depth. It is clear, there fore, that the instantaneous angular displacement of stator 27 and rotor 28 of synchro 26 will be a function of the rate of change of torpedo depth. The output from synchro generator 39 is applied to the differential synchro generator 47, and the currents in and the voltages between the output conductors of differential generator 47 will, in the cenventional manner, be determined by the relative angular displacement of rotor 48 and stator 46 of differential synchro generator 47, whereby the electrical signal fed to the synchro control transformer 26, i.e., the depth rate synchro, will be a function of the displace- Referring now to Fig. 3, there is illustrated a modified arrangement for converting hydrostat shaft motion into proportional electrical signals, on1y the hydrostat shafts and the electro-mechanical conversion components being shown for the sake of clarity. Synchro 50, in this modification, may be a synchro control transformer comprising a rotor 51 and a stator 52 which operates, in full accordance with well-known characteristics of such a synchro, to yield an electrical signal proportional to the sine of the difference between the angle defined by the stator voltages and the angle of displacement between its rotor and stator. Rotor 51 is drivably engaged with the rack 53' on depth hydrostat shaft 53, corresponding to the hydrostat shaft 20 of Fig. 1, as by means of the gear 54, whereby the rotation of rotor 51 will be proportional to the sea pressure acting on the hydrostat bellows associated with shaft 53. A mechanical differential 55 is provided in this modification and may be of the type comprising a pair of independently rotatable shafts 56 and 56, interconnected by 1 gaged with the rack 58' on depth rate hydrostat shaft 58,

corresponding to hydrostat shaft 19 in Fig. 1, as by the gear 54, and differential shaft 56 is drivably connected to rotor 51 of synchro 50, whereby the rotation of shaft 56' will be ,afunction of torpedo depth while the rotation of shaft 56fwillbe determined by the movement of damped hydrostat shaft 58. Thus, the angular displacement of' differential gear body 57 will be a function of the rate of change of torpedo depth. Differential gear body 57 is drivingly engaged with stator 52 of synchro 50 as by suitable driving means diagrammatically illustrated at 59. It will be apparent from the above, that the electrical signal delivered bysynchro 50 will be a summation function of torpedo depth (relative to that corresponding to initial adjustment of synchro 50) and rate of change of torpedo depth. The output of synchro 50 may be fed either into a differential synchro generator whereby to provide for automatic depth setting 'as in'the instance of Fig. 2, or, where mechanical means are provided for manual setting as'by initial angular adjustment of stator 52, the output gt synchro' 50 may be fed directly into the servo amplier 9. a InFig. 4 there is illustrated a further modification of the present invention, the hydrostat assembly '10 disclosed therein being substantially identical to that shown in Fig. 1 with the exception that the separate damping means or dashpot assembly has been eliminated, the damping means being incorporated into the depath rate hydrostat assembly. Only a portion of the hydrostat structure is shown in Fig. 4, the remainder of the hydrostat assembly being identical with that of Figs. 1 and 2 as shown or as modified by Fig. 3. The hydrostat assembly of Fig. 4 differs from that of Fig. 1 in that separate passages 60 and 61 provide communication between chamber 11' and bydrostat chambers 13 and 16 respectively. Passage 60 comprises either a restricted orifice, as shown, or may incorporate an adjust-able orifice valve whereby to vary the resistance to flow through passage 60, while passage 61 is unrestricted. Valve member 21, upon the torpedo exceeding a predetermined depth, is, as in the case of Fig. 1, moved into sealing engagement with valve seat 15 whereby to seal off both passages 60 and 61 from sea pressure. In this modification, fluid damping is provided by the sea water in chamber 13' and restricted passage 60. Thus, the diflerential pressure between chambers 11 and 13' or between chambers 13' and 16 will be dependent upon the rate of change of torpedo depth whereby the instantaneous differential displacement of hydrostat shafts 19 and 20 will also be a function of the rate of change of torpedo depth. The operation of this modification is identical to that of Fig. 1.

Modified means for drivably engaging the synchro 'and/or mechanical differential shafts with the hydrostat shafts is disclosed in Fig. 5 wherein a hydrostat shaft 70, which corresponds to either of hydrostat shafts 19 or 20, comprises, in this modification, a pair of spaced clamp members 71 and 72 fixed to shaft 70. Secured at opposite ends to said clamping members is a flexible member 73 which may be, for example, a nylon cord which engages and is wound around a pulley 74, corresponding, for example, to gear 32 in the modification of Fig. 1, the arrangement being such that axial movement of shaft 70 will cause rotation of pulley 74. This arrangement has the advantage of reducing friction between the parts and of eliminating back lash which would be inherent in the gearing arrangement of Fig. 1.

From the above it will be apparent that the present invention provides a torpedo depth control system having anticipating depth control characteristics which is simple in construction, owing especially to the essential similarity of the parts, which requires a minimum of precision of its manufacture, which is easily assembled, which requires a minimum of simple adjustments for proper operation, and which, because of its insensitivity to extraneous acceleration forces, provides reliable depth error and anticipation, or depth rate, components, whereby stable depth control of a torpedo may be achieved at set depth with a minimum of hunting or oscillating about set depth.

Obviously many modifications of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the present invention may be practiced otherwise than as specifically described herein.

What is claimed is:

1. In a torpedo depth control system, a first hydrostat, a first synchro having its rotor actuated by said first hydrostat, a second hydrostat, means for damping compressive and expansive movement of said second hydrostat, and a second synchro having its stator actuated by said second hydrostat and its rotor actuated by said first hydrostat.

The structure-according to claim 1, wherein an excitation voltage is applied to said first synchro and the output thereof is fed to said second synchro whereby the output of the latter will be a signal which is a function 7 both of torpedo depth and rate of change of torpedo depth..

' .3. The structure according to claim 2, and a differential synchro generator, the output of. said first synchro being fed to said differential synchro generator and the output of the latter being fed to said second synchro, whereby depth setting and steering maybe achieved by relative rotation of the rotor and stator of the differential synchro generator.

4. In a torpedo depth control system a first hydrostat bellows, a second hydrostat bellows, said first and second hydrostat bellows being subject to varying pressure in accordance with torpedo depth, means for damping compressive and expansive movement of said second hydrostat bellows, a synchro having rotor and stator members, one said member being driven by movement of said first hydrostat bellows, mechanical differential means having a pair of input shafts separately driven by movement of said first and second hydrostat bellows and having an output shaft .the angular displacement of which is a function of the instantaneous diflerential angular displacement of said input shafts, said synchro having its other said member driven by said output shaft, whereby said synchro, when energized by excitation voltage applied thereto delivers a signal which is a function both of torpedo depth and rate of change of torpedo depth.

5. In a control system for a body controllably movable into zones of varying pressure in a fluid medium, a first fluid pressure responsive device, a second fluid pressure responsive device, means for damping compressive and expansive movement of said second fluid pressure responsive device, a first synchro energized by excitation voltage applied thereto and having its rotor actuated by said first fluid pressure responsive device, a second synchro having its stator actuated by said second fluid pressure responsive device and its rotor actuated by said first fluid pressure responsive means, and means to feed the output of said first synchro, to said second synchro whereby the output of the latter synchro will be a signal which is a function both of pressure and of rate of change of pressure in said fluid medium.

6. In a torpedo depth control system, a pair of pressure responsive elements, first and second means attached to said pressure responsive elements and subject to movement thereby in accordance with the pressure exerted on said elements, damping means acting directly upon and resisting the movement of said second 'means in accordance with the velocity thereof, synchro means responsive to movement of said first means and to damped movement of said second means relative to said first means for providing an electrical signal which is a function of both torpedo depth and rate of change of torpedo depth, and valve means actuated by one of said pressure responsive elements for sealing both of the pressure responsive elements against sea pressure at a predetermined depth.

7. In a control system for a body controllably movable into zones of varying pressure in a fluid medium, a pair of pressure responsive elements, first and second means attached to said pressure responsive elements and subjected to movement thereby in accordance with the pressure of said fluid medium exerted on said elements, damping means acting directly upon and resisting themovement of said second means in accordance with the velocity thereof, and synchro means responsive to move ment of said first means and to damped movement of' said second means relative to'said first means for pro-- viding an electrical signal which is a summation func-- tion of both the pressure on the body and the rate of" change of pressure on the body, said damping means comprising a fluid dashpot assembly having an adjust-- 7 8 ble r tic? val or r ab q nt of tha x e 0f 2M5; .1 Frischc r v Feb.. 4; 1947; damping imposqd upon'movemgnt of said second means, $426,181 pgakig 'et a1. V :Aug. 26, 19' 47.:

' 7. I 2, 5,022 Hanna Au 10,1954 R r nws Cited i the of p t t 23593921 7 lgissac'k vNov. -9, 1951 1.

' UNITED STATES PATENTS 5 2 2 705 {Ras sse gt a1. V V 13m .55 1,997,412 Fischer Apr. 9, 71935 OTHER REFERENCES 7 I 2,231,715 Gulliks'en Feb. 11, 1941 'ServOmeCh-anism Fundamentals, 'pp. -20-24,37 and? 2,412,740 Morgan Dec- 17', 9 Lauer, Leshick and Matson, authors MqGrgw-Hill;1947.

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