US1603867A - Automatic steering apparatus - Google Patents

Description

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R. H. ROGERS VAr'J'LoMATlc STEERING APPARATUS Filed March 18,. 1922 2 Sheets-Sheet 2 Fig@ lnven-toh: Rober-i:` H. Rogers,

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narran stares ernten ROBERT H. ROGERS,`O1E` SCNECTADY, NEW YORK, ASSEGNO T@ GENERAL ELECTRIC CMPANY, A CRPORATION 01E NEW YORK. i

AUTUMATIC STEEBJNG AFPARATUS.

Application tiled llarch 18, 1922. Serial No. 544,945.

My invention relates to automatic steering apparatus for dirigible craft, such as ships and the like, and has for its object the,provision ot simple. reliable and emcient means whereby such cratt may be automatically steered along a predetermined course.

l ln the steering ot a dirigible cratt. tor enample, a ship, along a straight course byl the time taken by the ship in traveling trom port to port is materially greater than it the ship were caused to follow a straight course. `Furthermore, the eciency ot the propeller and propulsion machinery is decreased, and it is also practically impossible to calculate the distance traveled from the propeller turns.

By means ot my invention l am able to counteract at its inception any tendency on the part ot the ship to swing od its course. ln carrying out my invention l provide means responsive to both deviation and positional displacement of the ship with relation to the water for controlling the rudder so as to return the ship to a predetermined course. lln one torni ot my invention l employ a drag towed from the ship by a line ot considerable length. rll`his line identifies any course along which the ship may be set by manual control, and any turning ot the ship from this coursemunder the inboard end ot the line is instantly apparent. Control means are associated with the drag line in such manner that the rudder is automatically moved in response to the ships swing in a direction to counteract such swing. lily invention is adaptable to various systems tor actuating a ships rudder whether mechanical. steam. electrical, hydraulic or a combination ot such systems. By properly proportioning the drag to give the necessary pull. the tension on they line may be utilized directly as the rudder actuating torce.

For a more complete understanding of my invention reference should be had to the accompanying drawing in which Fig'. 1 is a plan view of automatic steering means tor a shlp embodying my invention; Fig. 2 is an elevation view showing the operating connection between the servo motor and the control for the rudder actuating means; Fig. 3 is an elevation view of the control deylce associated with the drag line; Fig.. l 1s a plan view of a ship provided with automatic steering means embodying my invention; Fig. 5 is a diagrammatic view showing the control system lor the electric servo motor: Figs. 6 and l are diagrammatic views showing a simplihed form ot my invention: while Fig. 8 is a plan view showing a moditied form of my invention.

Referring to Fig. 1 ot the drawing, although l have shown my invention in one form as applied to a well known electric hydraulic system for operating the rudder, which will he described only in general. itwill be understood that my invention is equally applicable to various other rudder operating systems. The particular system shown comprises a hydraulic plunger 10 operatively connected at its center to the tiller 11 and having its ends moving in opposed hydraulic cylinders lQ and 13 which are supplied with a suitable liquid through pipes 1t and 15 by a pump 16 continuously driven by an electric motor 17. 'll'he pump 16 is driven at a constant speed, and the pressure ont the liquid supplied by it to cylinders 1:2 and'13 may be varied by means of a control rod 18 so as to move piston 10 as desired to adjust the position ot the rudder. Control rod 18 is actuated in response to movement ot wheel 20 by the pilot through a hydraulic device ot a suitable well known form. This vhydraulic device is shown as consisting of two hydraulic cylinders 2l and 22. the plungers ot which are provided with racks cooperating with a pinion on the shaft ot wheel 20 so that as the wheel is turned in one direction or the other` as the case may be, onev ot the plungers is depressed while at the same time the other is raised a corresponding amount. Cylinders 21 and 22 are connected through pipes 23 and 2li to tubular, fixed. alined plungers 25 and 26, respectively, coperating with alined cylinders in a movable member 27. lt will be observed that movement of wheel 20 causes unbalanced hydraulic pressures in the cylinders of member 27, thereby causingr the member to move to equalize these pressures and repeat in terms of translationvthe movement ,of the wheel.

Member 27 isrconnected through a link 28 provided with a centering spring 29 of well known form to a lever 30 pivotally attached at or near its center to control rod 18. The lett hand end ot lever 30 is connected through a link 31 to tiller 11. yMovement of member 27 in response to movement of wheel 20 is thus transmitted to control rod 18 whereby pump 16 is caused to actuate plunger 10 in a corresponding direction, the movement of plunger 10 being transmitted through link 31 to lever 30 so as to return control'arm 18 back to its od position. lin this manner movement of wheel 2O by the ,helmsman is transmitted and applied automatically to tiller 11 to adjust the position of the rudder.

Referring to Figs. 1 and 4, in accordance with my invention l have Provided a drag line 35 having on its end a small drag 36, which line is attached to the end of an arm 3'? on the ship. Cooperating with the drag line, so as to be actuated upon angular move' ment of the ship under the drag line, is an electric switch shown in the form ot an arm 38 having its end attached to the drag line and being movable between two stationary` contacts 39 and'40. This switch, together with f arm 37, is\ mounted on a suitable pedestal support 38' (Fig. 3) secured on the deck ot the ship and preferably, as shown, at

some point on the keel line. 'llhe switch is in the control circuit of an electric servo motor 41, shown as a series motor, which is operatively connected through a reducing gear train 42 to a shaft 43 (Fig. 2) alined with link 28. Shaft 43 is provided with a screw 44 which cooperates with a nut 45 attached to a rectangular table or plate 46, whereby the plate maybe given lnovement of translation in one direction or the other by the electric motor.' Cooperating with the upper surface of plate 46 is an electromagnet 47 which .when deenergized is adapted to slide in suitable guides longitudinally ot plat-e 46. 'llhe electromagnet is operatively connected through a link 48 to the right hand end of lever 30, and is shown connected at a point coincident with the connection ot link 28 with lever 30. By energizing electromagnet 47, the servo motor may be operatively connected to lever 30. llt then controls the hy draulic rudder actuating mechanism.

A. follow up mechanism is provided tor. servo motor 41 whereby the position of arm 37 is temporarilyV changed upon operation ot the motor so as to move the inboard end of the dragline and disengage contact arm 38 trom its stationary Contact to open the -rnotor circuit. This mechanism comprises a link 50.connecting plate 46 to an arm 51 which rigidly secured to a rotatably .vided for motor 41. rlhis brake may be of any suitable form in which the brake is released upon the energization ot solenoid 54 and applied when the ysolenoid is deenergized.

Referring to Fig. 5, the servo motor 41 is provided with two field coils 55 and 56'which are oppositely wound and hence adapted to operate the motor in opposite directions. rlhe connection of the'motor with a suitable source ot electrical supply 59 is controlled through two contactors 57 and 58 so as to selectively include the eld coil giving the proper direction of rotation. Brake solenoid 54 is also included in the motor circuit. Contactors 57 and 58 are actuated by operating coils 60 and 61, the energization ot which is selectively controlled by switch arm 38. A control circuit is provided for electromagnet 47. rlhis circuit includes a switch 62 located adjacent the wheel 2O so that it may be conveniently opened or closed' by the lielmsman.

The operation of my invention will best be understood by reference to the elementary form thereof shown diagrammatically in Figs. 6 and 7, which form is adaptable torI follows in the wake of the sliip, as shown in Fig. 6,-wlien the steering may be turned over to the drag line. Upon deviation of the ship from the predetermined course, for example, to the lett or port, thevtiller will be moved to give the proper compensating Irudder ad- 'ustment, as shown in Fig. 7. lt will be observed that the deviation of the ship and the corrective movement given the rudder are proportional in both amount and velocity.

With the arrangement illustrated in Figs. 1 to 5 inclusive, the ship is first controlled vmanually by means of wheel 2O until it has been adjusted accurately on the predetermined course and held there suiciently long to bring the drag in the wake ot the ship. Previous to this setting of the ship, magnet 47 is deenergized by opening switch 62 so that during the manual control of the ship the magnet is lfree to slide on plate 46 to permit independent movement of member 27' under the control ot wheel 20. As the drag swings into position in the wake ot the ship, the servo motor 41 tends to keep arm 37 in such position that switch arm 38 does not touch either ot its cooperating fixed contacts,

lltl' reoaeer and the tinal position ot arm 37 will depend on the amount of leeway allowance taken into consideration in the rudder adjustment. For zero leewa-y, arm 3i' will take a position along the keel line of the ship. After the ship has been brought on the predetermined course, assuming no leeway allowance, the various parts of the system will Vbe as shown in Fig l of the drawing, control rodl8 being in a central position such that pump 16` is inoperative.

For automatic steering switch 62 is now closed to energize magnet l? which clamps tirmly on table t6, thus establishing a definite length ot operating connection between servo motor l1 and lever 30. Upon a slewing movement of the-ship trom it-s course. for example, to the left or port. by an amount greater than the freedom ot movement provided for contact arm 3S, the Contact arm will be moved to engage contact 40. as shown in F ig. 5. A circuit is thus closed for operating coil which picks up contacter 5i' closing the circuit for servo motor lll through tield coil 55. Brake solenoid l is at the same time energized and the brake released. 'llhe servo motor now operates in a direction to move plate -16 toward the starboard side. which movement is communicated through link i8 and level' 30 to valve rod 18,

whereby pump 16 is caused to actu-ate piston itl so as to move tiller 11 in a counterclockwise direction and thus compensate for the deviation of the ship. 'lhrough the follow up device tor servo motor l1. plate t6 moves with it arm 37 in a clockwise direction tending to cause contact arm 3S to disengage stationary contact 40. whereby the servo motoris brought to rest when it has responded in proportion to the swinging movement of the ship. rll`he circuit for the servo motor may be and usually is broken before the rudderhas been completely adjusted by hydraulic piston 10. The object in breaking in this manner the circuit of the servo motor in response to its own movement rather than subsequently in response to the swing ot the 'ship back on the course is to prevent excessive corrective movement ot the rudder. Without this arrangement the ship might be subjected to a series ot swinging movements. while with it the ship is vquickly brought back on the course.

As the ship swings back on the course,

contact arm 38 will be moved to engage contact 39. whereby the supply circuitwill be turn movement of arm 3T.

closed `tor operating coil 6l which picks up contacter 58. cl'sing the servo motor circuitthrough iield coil'j56. T he servo motor now operates in the opposite direction moving plate -lti back toward its initial position until stopped. by the opening ot its circuitl b v re- Pump i6 is thereby controlled so as to straighten the rudder by a small amount.

be controlled in this manner to gradually straighten the rudder by a number ot relatively small movements until when the ship has been brought back on the course. the rudder and the various parts ot the control system will be in their initial positions as shown in Fig. l. `lUpon swing of the ship toward the starboard side, contact arm 38 will be moved into engagement with contact 39 whereby the servo motor will be controlled to give the proper adjustment ot the rudder, whichl will be gradually straightened with the return movement ot the ship, as will be understood trom the previous descript-ion.

lt will be observed that the ship will not only be properly controlled in direction, but also in position with relation to any course on which it may be originally laid. llt the ship should be displaced in position to one side or the other ot the predetermined cour-Te, the drag line will extend at an angle with the center line ot the ship, since the drag will still follow on the predetermined course, or very nearly so. -fContact arm 38 will therefore be actuated to correct the positional displacement ot the ship.

'lhe amount ot clearance between Contact -arm 38 and contacts 39 and ll0 will vary with the particular conditions ot navigation encountered, and will be as-small as practicable. For example, sumcient treedom will ordinarily be provided to prevent contact from periodic yaw ot the ship due to the swell ot the ocean. lin extremely rough seas control ot the ship by the automatic steering system maybe impracticable. and in this event switch 62 will be opened and hand steering resorted to. V

The speed of the servo motor is such that the rudder is moved at a velocity greater than the highest possible velocity ot swing ot the ship. ln case of a persistent swing ot the ship ot considerable duration the servo motor, therefore, will loperate tor a number ot short periods, thus causing the rudder to beadjusted in steps, the duration of each step depending on the -velocity' ot swing ot the ship. Consequently, the rudder will be movedl with an average veloclty which is proportional to the velocity ot the ships swing causing the movement.

llt will be observed that any movement applied to lever 30 by servo motor 41 will be transmittedto member 30 ot the hydraulic repeater system whereby wheel 20 will be actuatedsso as to always indicate thel position llt) ot the rudder. rlhe position and movements of the wheeltherefore provide a convenientY The servo motor will this arrangement the breaking of, the circuit for the servo motor is made directly responsive to the rudder adjustment', although as in the arrangement previously described, it is not dependent on the response of the ship to the adjusted position of the rudder.

As shown also in Fig. 8, arm 38 may be provided with a pointer 65 which cooperates with a stationary arc shaped scale 66, suitably calibrated in degrees, and indicates on the scale the angle between the drag line and the keel line of the ship.l This angle, it will be observed, is an indication ofthe amount of leeway allowance being made by the ship, The indicator may be provided for the convenience of the skipper. I

It will be observed that by means of my invention, ll am enabled to utilize a controlling force, viz; the pull of the drag line, which is constantly applied and hence instantly available, as distinguished from control systems, such as those employing a gyrocompass, wherein the controlling force is zero under stable conditions and must be built up, whereby an appreciable time lag is introduced. u

While l have described my invention as embodied in concrete form and as operating in a specific manner in accordance with the provisions ot the patent statutes, it should be understood that'l do not 4limit my invention thereto, since various modifications thereoi` will suggest themselves to those i skilled in the art Without departing from the spirit` of my invention, the scope of which is set forth in the annexed claims.

What l claim as new and desire to secure by Letters Patent of thedlnited States, is:

1. Automatic steering means for a dirigible craft comprising a slender elongated member towed by said craft and thereby caused to take up a position defining a predetermined course for said craft, and steering means for said craft controlled by said member upon deviation of said craft from said course, whereby said craft is maintained on said course.

2. The combination with a ship, of automatic steering means therefor, comprising a drag line towed by said ship, and steering means controlled b said drag line upon deviation of said ship from a. predetermined course so as to return said ship to said course.

3. Automatic steering apparatus for a seltpropelled Ship, comprising a drag, a line connecting said drag to the ship, and steering means for the ship controlled by said line upon swinging movement of the ship so, as to maintain the ship on a predetermined course.

4. Automatic steering means for a ship comprising a drag, a line connecting said sive to Swingin movement of the ship with relation to sai line so as to maintain the ship on a predetermined course.

5. The combination with a ship, of automatic steering means therefor, comprlsing a drag line, operatingl means for the rudder of said ship, a motor for controlling said operating means, and control means for said motor actuated by said drag line upon swinging movement of said ship so as to return said ship to a predetermined course.

6. The combination with a ship, ot automatic steering means therefor, comprising operating means for the rudder ot said ship, control means therefor, an electric motor operatively connected to said control means, a drag line, and control means for said motor operated by said drag line in response to swinging movement of said ship, whereby .said ship is automatically returned to a predetermined course.

T. The combination with a ship, of automatic steering means therefor comprising operating means for the rudder of said ship.l control means therefor, a drag line, secondary operating means controlled by said drag line in response to swinging movement oi' said ship, and a releasable operating connection between said secondary operating means and said control means whereby said steering means may be independently adjusted to bring the vship on a predetermined coutse.

8. rl`he combination with a ship, of automatic steering means therefor, comprising operating means for the rudder of said ship, control means therefor, a drag line, a motor controlled by said dragline in response to swinging movement of said ship, an operating connection between said motor and said control meansincluding an electromagnet, and means for deenergizing said electromagnet for independent control ot said ship and for energizing said electromagnet for automatic control of said ship.

9. lli'he combination with a ship, of automatic steering means therefor comprising operating means for the rudder of said ship, control means therefor, a drag line, a motor controlled by said drag line in response to swinging movement of said ship, and an operating connection between said motor and said control means including an electromagnet adapted when deenergized to permit independent adjustment of said rudder for any predetermined course and when ene'rgized to establish an operating connection between said motor and said control means whereby said rudder is automatically adjusted so as to hold said ship on said predetermined course.

l0. rlihe combination with a ship, of aut/omatic steering means therefor, comprising operating means for the rudder oi' said ship, control means therefor, a drag line, a motor llo controlled by said 'drag line in response o energized an operating connection bet-Ween swinging movement of said ship.,l a Plate ref sald motor. and said control means whereby ciprocated by said motor, an operatmg arm said rudder is automatically adjusfted so as,

connected to saidl control means, vand an to hold said ship on said predeermined electromagnet securecl to said erm and restcourse. ing on saidl plate so as to Toe freev fno slide )In witness whereof, I have hei-@unto set M5 thereon when deenercfzed to permit inemy hand this 17H1 lay of March, 1922. pendent adjustment of sadi rudder for any predetemined comrse andi esnbllishng when RBERT H. RGERS.

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