US2015183A - Self-synchronous automatic pilot - Google Patents

Description

Sept. 24, 1935. 5 HODGMAN I 2,015,183

SELF SYNCHRONOUS AUTOMATIC PILOT Filed Oct. 27, 1931 4 Sheets-Sheet l GYRO i COMP/13S ll! //2 a //0 me e 8 INVENTOR Sept. 24, 1935. F, S HODGMAN 2,015,183

SELF SYNCHRONOUS AUTOMATIC PILOT Fiied Oct. 27, 1931 4 Sheets-Sheet 2 IIIIIIIIHZZ Sept. 24, 1935. F s, HODG N 2,015,183

SELF SYNCHRONOUS AUTOMATIC PILOT Filed Oct. 27, 1931 4 Sheets-Sheet 4 INVENTOR fiPEDER/GK 5J7 DEM/W.

.142 ATTORNEY Patented Sept. 24, 1935 UNITED STATES PATENT OFFICE 2,015,133 SELF-SYNCHRONOUS AUTOMATIC PILOT Application October 27, 1931, Serial No. 571,475

7 Claims.

This invention relates to improvements in automatic steering devices for ships wherein the course controller is automatically maintained selfsynchronous with the gyro compass. In the present automatic steering devices the controller is geared up to rotate many times for one rotation of the compass or ship in order to obtain accurate control. In case, howeventhere is a temporary circuit interruption between the controller l0 and compass, or in case the controller is turned faster by hand than the ship can follow, synchronism may be lost and may only he reestablished by hand setting, if the ships heading becomes displaced more than about on either side of the indicated course. According to my present system, the controller is made selfsynchronous so that no matter in what relative positions the controller and compass are at the time the circuit is thrown in, automatic synchronization is established and the rudder brought to the proper position to steer the ship on the predetermined course. My self-synchronous system, of course, has broader application than to the steering of ships and is adapted for any selisynchronous remote control system of a power motor. According to my invention, I prefer to insert an auxiliary controller or controllers and a small sensitive power motor between the compass controlled repeater motors and the main 3O steering motor. By this means a much quicker and sensitive control of the ship is obtained for the reasons outlined in my prior application Serial No. 529,939 filed April 14, 1931 for Sensitive re mote control system and automatic pilot. Referring to the drawings,

- Fig. 1 shows in diagrammatic form mysystein as applied to automatic steering for ships.

Fig. 2 is an elementary wiring diagram of the same. 40 Fig. 3 is a detailed plan View of the cam switches used to operate the main steering motor.

Fig. 3-A is a side elevation of the same.

Fig. 4 is a section taken approximately on line c t of Fig. 3-A.

45 Fig. 5 is a vertical section through the primamr Fig. 10 is a wiring diagram of a modified form of control for the steering motor.

In Fig. 2 the sending instrument, in this case a master compass, is represented at i and as usual in self-synchronous remote control systems the 5 compass is provided with a course transmitter 2 connected at a l to 1 speed to the compass, and a fine transmitter 3 connected at multiple speed, such as a 36 to 1 to the compass. The course transmitter drives the coarse repeater motor l 1 and the line transmitter drives the fine repeater motor 5 at the controller. Each motor may be provided with a repeater card 6 and 'l if desired (Fig. 1). The motors and transmitters are preferably of the alternating current self- 35 synchronous type (see Fig. 2) wherein the fields are continuously excited from an A. C. source S and the armatures are electrically connected.

It is well known that such motors are accurate only when little or no load is placed thereon. 20 Therefore, I mount the power motor control contacts directly on the shaft of the motor. Also, instead of employing onlya contactor on the fine motor, I prefer one on each motor in order to secure self-synchronisni as hereinafter described. 25 The course motor carries the trolley arm and the fine motor the trolley arm 9, both arms being shown as having a trolley at each end. lhe fine controller may be of the usual form in which two trolleys bear respectively on upper ring ill and lower slip ring ll, (Figs. 8 and 9). Said rings are shown in Fig. 2 as of different diameter for the sake of clearness. The upper ring is divided into two parts lll-l(l' by narrow strips of insulation and a lead-in brush it bears on the slip ring i i to lead current into the trolleys. If, there fore, the trolleys in Fig. 2 are turned clockwise detail in Figs. 8 and 9 and hereinafter described.

If, on the other hand, trolleys are rotated so counter-cloclcwisa the circuit is completed through the segment to the other field winding it of the motor, thus driving the motor in the opposite direction.

The motor he made of suincient size 5 to turn the rudder directly or through an auxiliary steering engine, but I prefer to make the motor l5 very small so as to respond very quickly to the controller and to use said motor only to operate additional cam-operated contacts 48- 4|42, which in turn control the main steering motor 43, and to place a lost motion device between said motor and its controller as hereinafter described.

Except forthis feature the system so far described is quite similar to the systemslat present in use; but without a connection from the coarse or self-synchronous motor 4 the device would not be completely self-synchronous. I, therefore, also provide the controller 8 on motor 4 with means for causing the same to assume control of motor l5 when the ship is off course more than the angle of self-synchronism of controller 9, which, with a 36:1 ratio, would be about 5". In order to effect this purpose, the lead-in current to the trolley 9 is led first to the trolley arm 8 and from thence, in order to reach the trolley 9, current must pass from the lower trolley 8 through the short contact segment 25 and thence through the annular external slip ring 26 connected to segment 25 and thence through the brush 21 to the trolley arm 9 (for actual construction see Figs. 8 and 9). It will be seen, however, that if the trolley 8 is rotated either to'the right or left through an angle greater than the width of the segment 25, the current to the trolley 8 will be interrupted and the fine controller rendered inoperative. Under these conditions, however, the upper trolley 8" is moved off the insulated sector 3| which is of about the same angular width as 25, bringing 8" into contact with one of the live segments 29 or 30 which are connected through the slip rings 29' and 30' (Fig. 9) and brushes l2 and I3 to said field windings l4 and I6 respectively. Therefore, when the ship is off its course by an angle sufficient to move the trolley 8" oil the insulated segment 3| and the trolley 8' off the corresponding live segment 25, the coarse controller operates the motor to bring the ship around to within the predetermined degree of synchronism, i. e., within the limits of self-syn chronism of the fine controller. At this point, however, the coarse controller becomes inoperative by engagement of the trolley 8" with the dead section 8| and the fine controller becomes operative so that the fine controller alone will bring the ship on to exactly the right course.

There is, of course, provided a follow-back connection between the motor I5 and the controller contacts. The gear connections are diagrammatically shown in Fig. 1. Motor I5 is shown as connected to double reduction gearing 50- to a shaft 5| on which is mounted a gear 58 turning a gear 59 on shaft 60. In this shaft is interposed a lost motion device 6| for the purpose, among others, of eliminating the yaw of the ship. This device is shown as consisting of a sleeve 62 (see Fig. '7 having a pair of triangular slots 63 and 64 therein. The shaft 60 has a pin 65 thereon engaging slot 64, while a complementary shaft 56 has a pin 61 engaging slot I53. Sleeve 62, therefore, furnishes a loose adjustable lost motion connection between the shafts 6|] and 66, the amount of lost motion being varied by adjusting the sleeve longitudinally on the shafts. This adjustment, as shown, is effected from a pinion 68, the teeth of which mesh with annular rack teeth 89 on the exterior of the sleeve, the pinion being adjustable from a knob 10 in accordance with the readings of cooperating pointer and scale 1|.

The shaft 58 is shown as driving a cross shaft 12 through spiral gearing 13. Said cross shaft is shown as geared through one-to-one spiral gearing" to turn the contact rings III of the fine transmitter. The shaft 12 at its other end drives corresponding contact rings 28-49 of the coarse transmitter through suitable reduction worm gearing 15.

Shaft 5| also drives one arm 520i a differential gear train 53. The central or planetary arm of 10 said train is shown as revolved from a worm 54 turning a wormwheel 55 thereon. Said worm in turn is adjusted from the handwheel 56 by which course changes or corrections are introduced in the usual manner. 15

As above indicated I prefer to make the motor I5 very light so as to quickly respond to the controller on the repeater motors to actuate the main contacts for the main motor 43. The lost motion device above described cooperates to this 20 end by causing motor Hi to turn through a large initial. angle whenever it is first started, thus always closing the contacts on the main controller for a very small deviation of the ship (on the order of 5 minutes or less). For this pur- 25 pose the third arm 51 of the differential drives one arm 16 of the second differential 11 through gears 90, 90. The second arm 19 is driven from a follow-back repeater motor 18 actuated from a transmitter connected with the motor 43 to 30 furnish a follow-back connection from motor 43 to the main controller. A hand synchronizing knob 18' may be employed if the motor is not of the self-synchronous type. As shown, the repeater motor 18 is connected through gearing 8| to a 35 worm B2 driving a wormwheel 83 forming a planetary arm of the gear train. The third arm of said train rotates a shaft 84 which rotates through suitable gearing 85 a plurality of cams 86-81--88 which operate the switches to control 40 the motor. As shown, the cam 86 'has a one-toone connection to the shaft 84 while the other two cams are driven through a step-down gearing 89-98-9| so as to be rotated, say, at 1 to 18 speed. Cam 86, therefore, controls the fine con- 45 tacts 40--40' (Fig. 2) while the other two cams control the coarse contacts 4 I, 42 and 42'. These contacts and motor 43 are preferably placed on the ship's main D. 0. power circuit represented at P, while the motor |5 maybe actuated from 50 the lighter single phase circuit used to operate the repeater system of the compass and controller.

The fast and slow cam contacts may control the motor synchronously in a manner similar to the 55 commutator'contacts above described. Thus normally the fast contacts 40 and 40' are in control of the motor, the circuit to the same being closed by the switch 4|, the roller of said switch resting on the raised portion 81 of the cam 81. In case, 60 however, synchronism is lost, the roller of contact 4| will ride down on the lower portion of the cam 81 thus breaking the circuit to the contacts 40- 40'. At the same time one of contacts 42-42 will be made to operate the motor from the slow 5 or self-synchronous cam 88. Inthis case the -motor is shown as having a double wound armature with two commutators 43'--43" instead of a double wound field as in motor l5, although it is obvious that either form of winding may be 7 employed in either case. The field 9| is shown as excited directly from the line. 92 and 93 are limit switches designed to be open when the rudder R approaches the limit of its movement in either direction. The rudder is shown diagram- 75 matically as turned from a rack bar I00 which is reciprocated by the rotation of pinion IOI on shaft I02. There is also shown an electro-magnetic' clutch 94 between shaft I02 and the shaft I03 of motor 43. Said clutch remains closed only while the electric circuit to the servo motor is closed but which is disengaged when this circuit is broken, thus freeing the rudderfrom the load of the motor 43 when it is desired to steer by hand.

In Fig. 1 motor 43 is shown as driving the rudder R through the usual telemotoit system, the motor being coupled to the main steering wheel 95 through gear box 96', sprocket and chain 96, and clutch 94, the handwheel operating the rudder through the telemotor or straight hydraulic servo-motor system represented generally at 9'! and 98.

Fig. 10 shows a simplified wiring diagram of the control of the power motor 43 only. In this case the cam driven contacts 4!); 40', 4!, 42, 42' reverse the motor through auxiliary relay contacts 99, 99', I00, ma" operated from windings NH and H12 in circuit with cam contacts. In this case the motor is reversed by reversing the current through the armature while leaving the current through the shunt field Hi3 and series field ma unchanged. Dynamic breaking may be pro vided, if desired, by contacts M5, M15, resistance l0! and coil Hi6 operating switch Hill.

I also prefer to provide at the controller an indication of the rudder movements as well as of the ship movements so that the pilot may observe promptly whether the helm has moved in response to the controller and also whether the ship is following the helm properly. For this purpose I have shown an upper dial Hill which may be the shape of the ships hull and is driven from shaft its of gear it, the movements of this shaft representing the differential of the compass movements and the handwheel 5% so that the dial its constitutes a course change indicator when read on the stationary index Mil. Beneath the indicator its is a rotary dial ill having index M2 thereon representing the position of the rudder. This dial is shown as rotated from a worm M3 on shaft lfl l driven in turn from a gear spiral l is on differential it). Indicator M2, therefore, shows the rudder position being actuated from the rudder follow-up motor According to my present invention, l effect the adjustment known in the art as the weather adjustment in a different manner than hereto fore accomplished. This adjustment is for the purpose of varying the sensitivity of control so that in calm weather very accurate steering may be obtained while in rough weather over-warloing of the steering engine may be avoided by lessening the sensitivity of the device. According to my present invention I effect this purpose by varying the normal speed of the motor instead of varying the play in a lost motion ccnnection between the compass and controller as heretofore generally done. his has theadvantage that the sensitivity o control is not because a deviation of its course which persists longer than the normal period. of weather yaw will always cause a rudder response.

it is connected to one side or the A.

When the weather is bad and a non-sensitive control is desired the rheostat R is placed on the slow speed contact 8. In this position, al-

though the counter E. M. F. in the motor is control is desired for fair weather steering, it is placed on contact F. In the latter position it will be seen that that portion of the resistance in series with the armature is reduced to a minimum, while that portion in shunt with the arma ture is increased to a. maximum. The use of the shunt resistance also serves to steady the motor when operated on alternating current and improve the starting torque, especially at low speed.

Inaccordance with the provisions of the patent statutes, 1 have herein described the principle and operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patent is: l. l'n'a self-synchronous receiver, the combination with a repeating deviceof coarse and line repeater motors, the former of which is adapted to be driven from a coarse transmitter having a one-to-one drive with the sending instrument and the latter to be driven from a fine transmitter having a multiple drive from said instru merit, a power motor for driving said device, a.

between said last-named contacts and the con c tact on the second of the first mentioned cams whereby said contacts are rendered inoperative when the receiver out of synchronis more than a predetermined angle, and a circu other wise normally completed for normally driving said power motor in either direction as one or the other of said contacts is closed.

in a self-synchronous power means for tuming a heavy object, a reversible power motor, a contact device comprising a cam an a pair cz? reversing contacts operated thereby for normally operating said motor, an auxiliary con-- tact device driven at a :iractional speed of n device and at a one to one ratio with ohlect, comprising a pair of cam a con tact on one surface iorbrealring the circuit to pair of contacts when the angle said surface and contact exceeds a predeter -ed value, a pair of reversing contacts on the other surface adapted to assume control of said ill motor as said circuit is broken. and follow-back connections from said motor to said cams and contacts.

3. In an automatic steering device, the combination with the controller and steering motor, of a follow-back connection between said motor and controller including a driving shaft, a driven shaft, and an adjustable lost motion connection between the same comprising asleeve for connecting the ends of said shafts, said sleeve and shafts having cooperating pins and triangularlyshaped slots for said pins, and means for ad- Justing said sleeve longitudinally along said shafts to vary the amount of lost motion.

4. In an automatic steering device, the combinatlon with the controller and steering motor,

of a follow-back connection between said motor and controller including a driving shaft, a driven shaft, and an adjustable lost motion connection between the same comprising a sleeve for connecting the ends of said shafts, a pin on each of said shafts taking in a triangularly-shaped slot in said sleeve, and means for adjusting said sleeve longitudinally along said shafts to vary the amount of lost'motion.

5. In an automatic steering device, a master compass actuated controller, a relay. motor excited therefrom, relay contacts actuated by said motor, a main steering motor actuated from said contacts, and a weather actiustment for varying at will the speed at which said relay motor is actuated from said controller.

6. In an automatic steering device, a master compass controller, a relay motor excited therefrom, relay contacts actuated by said motor, a main steering motor actuated from said contacts,

and means for varying at will the speed at which.

said relay motor is actuated from said controller as a weather adjustment including a resistance shunted across the armature but not the series field thereof, and means for tapping one side of the line into variable points therein to vary the proportion thereof in series with and in shunt with said armature,

'7. In an automatic steering device, a master compass actuated controller, a relay motor excited therefrom, a follow-back connection from said motor to said controller including a lost motion device, relay contacts actuated by said motor, a main steering motor actuated from said contacts, and a weather adjustment for varying at will the speed at which said relay motor is actuated from said controller.

FREDERICK S. HODGMAN.

Images