US 3019969 A Description (OCR text may contain errors) Feb. 6, 1962 c. F. ABT ET AL TORPEDO INTERCEPT CALCULATING APPARATUS 3 Sheets-Sheet 1 Filed May 25, 1953 5T0. cosA Ucos(Bur G-Br) QUULW T012 PEDO 'EUN U INVENTORS. CLIFFORD F'. ABT RICHARD Y. MI NEE BY ATTOFNZX Feb. 6, 1962 c. F. ABT ET AL TORPEDO INTERCEPT CALCULATING APPARATUS 5 Sheets-Sheet 2 Filed May 25, 1953 INVENTORS. ABT Y. M"? ATTOPNEY. CLIFFORD F. RICHARD UL)? ODUBNOP Feb. 6, 1.962 c. F. ABT ET AL TORPEDO INTERCEPT CALCULATING APPARATUS 5 Sheets-Sheet 3 Filed May 25. 1953 IN V EN TORS'. CLIFF'OED F. ABT RICHARD Y. MINEE BY f ATTOF/VEK United rates Patent U 3,019,969 TORPEDO NERCEPT CALCULATING APPARATUS Clifford F. Abt, Long Island City, and Richard Y. Miner, Port Washington, N.Y., assignors to American fiosch Anna Corporation Filed May 25, 1953, Ser. No. 357,262 9 Claims. (Cl. 235-615) The present invention relates to ordnance calculating apparatus and has particular reference to apparatus for regulating the path of a torpedo. Modern torpedoes are controlled by gyroscopes by means of which the torpedoes are made to turn through a predetermined angle, after a predetermined travel in water, and then to continue on a straight line to intercept the target. The present invention makes use of data describing the motion of the target, the motion of the attacking vessel and the ballistic characteristics of the torpedo to calculate the angle through which the torpedo must turn to cause the torpedo to intercept the target. For a better understanding of the problem involved and the method of solution, reference may be had to the accompanying diagrams, in which: FIG. 1 illustrates the geometrical problem and its solution; FIG. 2 is a simplified schematic diagram of the solution circuit; FIG. 3 illustrates the geometry involved when the target is traveling a curved course; FIG. 4 illustrates a typical variation of torpedo speed with length of torpedo run; FIG. 5 is a simplified schematic of a portion of FIG. 2; and FIG. 6 is a preferred compensation circuit connected in a portion of FIG. 2. For ease of description, the following assumptions have been made in the problem: (a) the point of observation of the target and the point of launching the torpedo are identical. (b) the effect of the torpedo depth is ignored, and (c) the correction required to compensate for gyro precession due to earths rotation is neglected. With reference now to FIG. 1 of the drawings, a torpedo fired from the deck of the moving attacking vessel 0 follows the path 0, b, c, d, e, where 012 is the path in air, and b, c, d, e, is the path in water. At the same time the target ship E travels along a fixed course at a constant speed, S, from its observed initial position which is at a range R from O and at a relative target bearing Br from the fore and aft line of own ship, to the position e, where the torpedo intercepts the target. The target angle, between the line of sight and the target course, is the angle A. The complete torpedo path is composed of several small segments which are defined as follows: ob is the travel of the torpedo in air before the torpedo enters the water at the splash point b, and is the vector sum of 0a and ab. 0a is the result of the speed So of own ship and is equal to SoTf, where Tf is the time of flight, i.e. the time the torpedo is in air. T is proportional to line of vessel 0. Bur is known as the relative tube bearing in the horizontal. The length of ab is designated as Bfllhflfi Patented Feb. 6, 1962 Ma and is equal to SeTf-l-M where Se is the ejection velocity of the torpedo and M is the length of the tor pedo. M, is added to SeTf to determine the point where the nose enters the water, since SeTf is merely the point where the propellers of the torpedo hit the water. he, or the reach M, is the initial straight travel in water, along a continuation of the path ab. At 0 the turning mechanism of the torpedo becomes eifective and the torpedo begins to execute a turn. M may be of different value for right and left hand shots. cd is the curved portion of the torpedo track and is assumed to be an arc with a constant radius of curvature Z. If the central angle through which the torpedo turns is G degrees then the length of cd is proportional to Z1rG/ 180. Z may also have diiferent values for right and left hand turns. de is the final straight track of the torpedo in the direction the torpedo is moving when the turn is completed. The total length of the torpedo track in water bcde is represented by U. The length of U may be expressed as SaTa where Sa is the average running speed during the run U and Ta is the time of run. The value Sa is based on a tactical speed 8 which is known for a given set of proof conditions of battery electrolyte temperature, sea water temperature and depth of torpedo run, and various corrections to S due to deviations from proof conditions and variation of speed with length of run. Ta is equal to T -l-jT, where T =U/S and fl" is the sum of corrections to time T which correspond to corrections made to the speed S Referring now to FIG. 4, the horizontal line, curve I, represents the tactical speed S plotted against the length of run U, and the straight line through the origin, curve II represents the corresponding time T Curve III illustrates the average torpedo speed Sa while curve IV represents the time Ta which is the ratio of U/Sa. The difference between curves IV and II or the curve V represents the correction time jT. In solving the problem of FIG. 1 the curves II and V are known, and are combined to give the curve IV or Ta=T +jT. Similarly, corrections for battery electrolyte temperature, sea water temperature and depth of torpedo run may be added to T to obtain Ta. For the purposes of this description however, T is understood to contain all necessary corrections to T v The problem then is to determine the angle G and the torpedo run U so that the torpedo intercepts the target at some point in the path of the target when the target continues to move along its course with a constant speed S. The solution of the problem will be outlined only briefly and the complete derivation of the solution will be omitted in the interest of simplicity. If the line ed is extended beyond d to g by an amount equal to db and lines parallel and perpendicular to R are constructed at points e and g respectively a right triangle gke is produced having a hypotenuse ge equal in length to U and an angle at 2 equal to (Bur+G-Br). The length of leg gk or U sin (Bur-l-G-Br) can be derived in terms already defined and can be shown to be equal to U sin (Bur+G- Br)=STa sin A-l-SoT; sin Br [(M+Ma) cos G-l-Z sin G] sin Similarly ek is equal to U cos (Bur-l-G-Br) and it can be derived that U cos (Bur+G- Br) R STa cos A- ST; cos Br Solutions for U and G are obtained in the computing apparatus by energizing the two input windings of an electromechanical resolver with voltages proportional to the right hand sides of Equations 1 and 2, and positioning the resolver rotor to the null of one output winding so that the displacement of the rotor corresponds to known as the solution angle, while the output voltage of the other output winding is proportional to U. The solution circuit is schematically illustrated in FIG- URE 2. For the sake of simplicity the usual booster and motor amplifiers are omitted from the diagram, as are the damping components and scaling elements. The type of torpedo being fired determines various constants, such as M, Z and S for example, of the Equations 1 and 2. These constants are inserted into the solution circuit by corresponding voltage dividers, the proper ratios of which may be chosen by a multiple selector switch operated by a single actuator bar or shaft such as shaft 67 in FIG. 2. Thus, for a B type of torpedo the actuator bar 67 is moved to the left and for an A type of torpedo to the right, as shown in FIG. 2, the torpedo type, A or B being indicated by markings near the positioning handle, at the left of bar 67 in FIG. 2. Many more types of torpedoes may be handled with a multiple position switch in place of the two position switch shown in FIG. 2, but the principle of invention remains the same. The target motion is observed from the attacking vessel and by computing apparatus, not shown values of R, A, S and Br are determined. Also, the values of own ship speed, S and the angle Bur are known. The description of the present invention will be started from the solution or set-up resolver 11 which is found near the center of FIG. 2. The output voltage of secondary winding of the resolver is applied selectively to resistors 12a and 12b by movable contact 13 of switch 14. A portion of the voltage between movable contact 13 and the respective taps 15a and 15b is simultaneously chosen by movable contact 16 of switch 14 so that the magnitude of the voltage between the movable contacts 13 and 16 is proportional to l/S of the magnitude of the output voltage of secondary winding 10. The movable contacts 13 and 16 are operated by the actuator bar 67. Assuming for the moment, that the output voltage of secondary winding 10 is proportional in magnitude to an arbitrary value X, the voltage output of switch 14 is proportional in magnitude to X S The X voltage of secondary winding 10 is transformed into a proportional displacement of shaft 17 by the motor 18 and induction potentiometer 19 in the usual manner. Motor 18 drives the secondary winding 20 of potentiometer 19 the primary winding 21 of which is energized by an alternating constant voltage :1 The error voltage between the outputs of secondary winding 20 and secondary winding 10 energizes the control field winding 22 of motor 18, the main field winding 18' of which is energized by a constant voltage, so that motor 18'drives shaft 17 until the output of secondary winding 20 matches the output of secondary winding 10 and motor.18 is deenergized, whence the displacement of shaft'17 is proportional to X. Motor 18, and the other motors herein employed are preferably two phase induction motors Where the main field is excited by the voltage of phase one, which voltage is in quadrature with the control field excitation voltage derived from phase two and of the same frequency. Shaft 17 drives the cam block 25, one cam of which is automatically selected, as will be described, according to the position of actuator bar 67. As shown in FIG. 2 the cam 25a is in position to drive the secondary winding 23 of induction potentiometer 24 through rack and pinion 120, 121. The primary winding 24 of potentiometer 24 is energized by the constant alternating voltage of 4: so that the output voltage of secondary wind ing 23 is proportional in magnitude to some function of X, F (X), according to the shape of cam 25a. A typical form of the function F is shown by the curve V of FIG. 4, in which the abscissa corresponds to X and the ordinate, or the output voltage of winding 23, corresponds to F (X). Movable contacts 13 and 16 are connected in series with secondary winding 23 and primary winding 26 of induction potentiometer 27 in a manner such that the voltage energizing primary winding 26 is the algebraic sum of the other two voltages or is proportional in magnitude [gwoo] The secondary winding 28 of potentiometer 27 is displaced by shaft 29 proportionally to the speed, S, of the target so that the magnitude of the output voltage of secondary winding 28 is proportional in magnitude to The secondary winding 28 is connected to primary winding 30 of electro-mechanical induction resolver 31 directly through switches 192 and 32 when switch 32 is positioned to the right as shown in FIG. 2 by the course selector control bar 33, which is the constant course position. The purpose of switch 192 will be described later. Control bar 33 simultaneously actuates switch 34 to short circuit the primary winding 35 of resolver 31. The secondary windings 37 and 38 of resolver 31 are driven by shaft 39 according to the target angle A so that the output voltages of secondary windings 37 and 38 are respectively proportional in magnitude to The secondary winding 37 is connected in series with secondary winding 41 of resolver 40, secondary winding 43 of resolver 44 and the primary winding 46 of resolver 11 whence the voltage energizing primary winding 46 is the algebraic sum of the voltage outputs of the secondary windings 37, 41 and 43. The values of the magnitudes of the output voltages of the secondary windings 41 and 43 will now be derived. gized by the T voltage from terminals 53, 54 and the movable contact 57 is displaced along resistance 55 by shaft 58 according to the speed, So of own ship. Thus the output voltage of potentiometer 56, between one end of resistor 55 and movable contact 57, is proportional in magnitude to the product of S and T SoTf, or the length 0a of FIG. 1. The primary winding 59 of electro mechanical resolver 40 is energized by the SoTf output of potentiometer 56, while the rotor windings 41 and 42 of resolver 40 are driven by shaft 60 which is displaced by an amount proportional to Br, the relative target hearing. The output voltages of rotor windings 41 and 42 are therefore proportional in magnitude to SoTf sin Br and SOT f cos Br respectively. Shaft 60 also drives one input to mechanical differential 61, the other input shaft 62 of which is displaced by an amount proportional to Bur, the relative torpedo tube bearing. The output shaft 63 of the differential 61 is displaced by an amount proportional to the difference between the input shaft displacements or by an amount proportional to (Br-Bur) The T voltage of terminals 53 and 54 is also applied to resistors 64a and 64b of the Se voltage divider 64. Taps 68a and 68b on the respective resistors 64a and 64b are connected to the right and left hand stationary contacts 69a and 69b respectively of switch 65, the movable contact 69 of which is operated by the torpedo type selector bar 67. The resistors 64a and 64b are voltage dividers in which the output voltage, taken across movable contact 69 and transformer tap 54 is proportional to the product of the input voltage T f and the voltage divider ratio Se, for the torpedo type A" or B as selected by the bar 67. The voltage across contact 69 and tap 54 is therefore proportional in magnitude to SeTf. The secondary winding 71 of transformer 72 energizes the resistors 73a and 73b. Two taps 74a and 75a on resistor 73a are connected respectively to the right hand stationary contacts 76a and 77a of switch 78, while two taps 74b and 75b on resistor 73b are connected respectively to the left hand stationary contacts 76b and 77b of switch 78. The movable contact 76 cooperates with the stationary contacts 76a and 76b, while movable contact 77 cooperates with stationary contacts 77a and 77b, both movable contacts 76 and 77 being operated by the movement of actuator bar 67. The movable contacts 76 and 77 are connected respectively to the stationary contacts 79 and 80 of switch 81. The taps 74a and 75a are chosen so that the voltages between tap 71' of secondary winding 71 and respective resistor taps 74a and 75a are proportional in magnitude to the torpedo reach, M, for right and left hand torpedo shoots respectively, for an A type torpedo. Also, the voltages between tap 71' and the respective resistor taps 74b and 75b are proportional in magnitude to the torpedo reach, M, for right and left hand shots for a B type torpedo. Secondary winding 84 of transformer 72 energizes the resistors 85a and 85b, the center points of which are connected to the center tap 84 of winding 84. Taps 86a and 87a on resistor 85a are connected to the right hand stationary contacts 88a and 89a respectively of switch 90, while the taps 86b and 87b on resistor 85b are connected to the respective left hand stationary contacts 88b and 89b of switch 90. The movable contacts 88 and 89 of switch 90 are connected to the respective left and right hand stationary contacts 91 and 92 of switch 93. The taps 86a and 87a of resistor 85a are chosen so that the voltages between center tap 84 and the respective contacts 881: and 89a are proportional in magnitude to the right and left values of the turning radius Z for an A type torpedo, which taps 86b and 87b are such that the voltage between center tap 84 and contacts 88b and 89b correspond right and left values of Z for a -B" type torpedo. Movable contact 82 of switch 81 and movable contact 94 of switch 93 are operated simultaneously by the actuator bar 95 which is in turn operated by the cam 96 to either the right hand or left hand position. Cam 96 is driven by the shaft 97 which is the output shaft of mechanical differential 98 and the angular displacement of which is proportional to the difference between the displacements of the input shafts 48 and 63. If the displacement of shaft 97 is called 0, and the displacement of shaft 63 is (BrBur), then the displacement of shaft 48 is (Bur-Br-I-). Movable contact 82 of switch 81 is connected in series with the secondary winding tap 71' of transformer 72, movable contact 69 of switch 65 secondary winding tap 54 secondary winding 99 of the transformer 51 and the primary winding 100 of electro mechanical resolver 101 so that the voltage energizing the primary winding 100 is the algebraic sum of the voltage outputs of the voltage dividers 73 and 64 and secondary winding 99. The output voltage of secondary winding 99 is proportional in magnitude to M the mean torpedo length whence the voltage energizing the primary winding 100 is proportional in magnitude to (M +SeTf+M or (M +Ma). The other primary winding 10 2 of resolver 101 is connected to center tap 84 of transformer secondary winding 84 and to the movable contact 94 of switch 93 so that the voltage energizing primary winding 102 is proportional in magnitude to Z while the polarity of the voltage depends on the position of cam 96. V The secondary windings 103 and 104 of resolver 101 are driven by shaft 97 whose displacement is proportional to 0 as previously described so that the voltage outputs of secondary windings 103 and 104 are respectively proportional in magnitude to (M+Ma) cos 6+2 sin 0 and (M-i-Ma) sin 0Z cos 6 The Z voltage across primary winding 102 also energizes the primary winding-105' of induction potentiometer 105 through transformer 66 so that the voltage energizing primary winding 105 is proportional in magnitude to Z1r/180. Shaft 97 drives the secondary winding 106 of potentiometer 105 so that the output voltage of secondary winding is proportional in magnitude to Z1r6/ 180. A resistance potentiometer may be used in place of the induction potentiometer 105, if desired. Movable contact 82 and winding tap 71' are connected in series with secondary winding 103 and 106 'of resolver 101 and potentiometer 105 respectively, and with primary winding 107 of resolver 44, so that the voltage energizing primary winding 107 is the algebraic sum of the outputs voltage divider 73 and secondary winding 106 less the output 'of secondary winding 103, or is proportional in magnitude to M+%%'[(M+ Ma) cos 0+2 sin 0] Movable contact 94 and winding tap 84 are connected in series with secondary winding .104 of resolver 101 and with primary winding 108 of resolver 44 so that the voltage energizing primary winding 108 is the algebraic sum of the output voltages of voltage divider 85 and rotor winding 104 and is proportional in magnitude to Z+(M+Ma) sin 6--Z cos 0 The secondary windings 43 and 109 of resolver 44 are driven by the shaft 48, whose displacement is proportional to (Bur+0Br), so that the output voltages of secondary windings 43 and 109 are respectively proportional in magnitude to: +[(M+Ma) sin 0-2 cos 0+2 cos (Bur-l-0Br) and Thus, the voltage energizing primary winding 46 of resolver 11, as previously described to be the algebraic sum of the output voltages of secondary winding 37 of resolver 31, secondary winding 41 of resolver 40 and secondary winding 43 of resolver 44, is proportional in magnitude to: The other primary winding 110 of resolver 11 is connected in series with secondary winding 109 of resolver 44, secondary winding 42 of resolver 40, secondary winding 111 of induction potentiometer 112 and secondary winding 38 of resolver 31 in a manner such that the voltage energizing primary winding 110 is the algebraic difference of the output of secondary winding 111 and the sum of the outputs of the secondary windings 38, 42 and 109. The secondary winding 111 of potentiometer 112 is displaced according to the range R by the shaft 113 while primary winding 114 is energized by theconstant alternating voltage of so that the magnitude of the output voltage of secondary winding 111 is proportional to the range R. Thus, the voltage energizing the primary winding 110 of resolver 11 is proportional in magnitude to: The secondary winding 115 of resolver 11 energizes the control field winding 116 of motor 117, the main field Winding 118 of which is energized through switch 118, by a constant alternating voltage b; in quadraturewith the control field winding 116 excitation; Motor 117 'drives shaft 48 and the secondary winding 115 of resolver 11 until the output of winding 115 is zero and motor .117 stops where the displacement of shaft 48 is proportional to the assumed value (Bur+-Br). Since the output voltage of 'secondarvwinding is proportional in magnitude to the assumed value X, and the displacement of shaft 48 is (Bur+6Br) when the secondary winding 115 is in the null position, the excitation voltages of primaries 46 and 110 are proportional in magnitude to X sin (Bur+0--Br) and X cos (Bur-f-B-Br) respectively. Thus, it may be written that: X sin (Bur-l-fi-Br) +F(X)]S sin A +80T; sin Br-HKM-l-Ma) sin 0 +ZZ cos 6] cos (Bur+0 Br) +[M+ g M+ Ma) cos 0 Z sin a] 4 in (Batwrl (3) cos (Bu1+0-Br) V Comparison of Equation 3 with Equation 1 and Equation 4 with Equation 2 shows that the Equations 3 and 4 are solved when X is equal to U and 0 is equal to G, assuming a properly designed cam 25a such that F(X) is proportional to the correction time jT, or is proportional to (Tg-l-jT) or Ta. In order that the terms making up the outputs of windings 103 and 104 of resolver 101 add together properly for all values of G, the Values of Z and M are instrumented in a manner such that Z has a positive polarity for right hand shots (G=O to +180") and has a negative polarity for left hand shots (G=0 to +180) while the polarity of M may be either positive or negative for right or left hand shots. (The ballistic value of Z is always positive). Thus, cam 96 operates the switches 81 and 93 whenever the displacement of shaft 97, which is proportional to G passes through zero or 180. For displacements of shaft 97 between 180 and 360 the movable contacts 82 and 94 of switches 81 and 93 respectively are operated to the left so that the Z voltage energizing stator windings 102 0f resolver 101, and the transformer 107 is proportional to Z and the M voltage is proportional to the M value for a left hand shot. Similarly, when shaft 97 is displaced between 0 and 180 the Z- voltage is proportional to +Z and the M-voltage is proportional to the M value for a right hand shot. It will be seen however that the output of potentiometer 105 is always proportional to +Z since the excitation voltage of the primary winding 105 reverses when the rotor winding 106 passes through zero. It was previously stated that the proper cam block 25 is automatically selected by the selector bar 67. The circuit by which this is accomplished is seen in FIG. 2 and is described in the following paragraphs. The cam block 25 is carried by the carriage 122 and .is driven by the shaft 17 by means of a spline (not shown) such that the cam block 25 is free to slide along the 'shaft 17. An extension 123 on carriage 122 operates the movable'contact 124 of switch 125, the stationary contacts 126 and 127 of which are connected to the stationary contacts 128a and 12817 of switch 129 and also to the secondary winding 130 of transformer 131. Resistors 126a and 127a are interposed in the connections to switch 129. The movable contacts 132 and 124 of switches 129 and are connected to the control field 133 of torque motor 134. Assuming that the conditions of FIG. 2 are stable, then the actuation of the selector bar 67 to the left causes the voltage of secondary winding to be applied to the control field of winding 133 the torque motor 134 which actuates the sliding contacts 135 and 136 to the right and left respectively, thereby completing the circuits between stationary contacts 137 and 138 and between contacts 139 and 140 respectively. Closing of contacts 137 and 138 energizes relay Winding 141. from power supply 142, which operates the switch 143 to apply the voltage of one half of secondary winding 144 to the control field 145 of motor 146. Motor 146 drives the pinion 121 to lift the cam follower 120 from the surface of cam 25a when the cam follower 120 reaches the end of its travel the cam follower 120 closes switch 147a which is connected to the center tap 147 of secondary winding 144 and also to the control field winding 148 of motor 149. Contact 140 is connected to one end of secondary winding 144 and the contact 139 is connected to control field winding 148 so that closure of contacts 139 and 140 and closure of switch 147a energizes the motor 149 to drive the pinion 150 which meshes with rack 150' on cam carriage 122. Motor 149 therefore drives the carriage 122 until the movable contact 124 of switch 125 is free of the stationary contact. In this position the cam 25b is located opposite the cam follower 120, and control field 133 of torque motor 134 is deenergized. The movable contact 124 is an elongated slider which cooperates with both stationary contacts 126 and 127 whence the resistors 126a and 127a are provided to prevent short circuiting the secondary Winding 130. Deenergization of control field winding 133 of torque motor 134 allows the sliders 135 and 136 to return to their normal position where the sliders cooperate only with the respective center contacts 137 and 139. Thus relay winding 141 and motors 149 are deenergized and motor 145 is energized by the opposite half of secondary winding 144 to urge the cam follower against the surface of cam 25b, which is shaped according to the correction time T for a B type torpedo. In order to preclude disturbance of the motor 117 which controls the solution resolver 11, the contacts 137 and 138 energize an additional relay 141 which disables the motor 117 by deenergizing the main field winding 118. Motor 18 may be simultaneously disabled by a similar relay (not shown). A change in any one of the inputs of So, Br, Bur, R, A or S will cause motor 117 to seek a new balance position and present a new solution for both U and G. In practice the S0, Br, R, and A and S shafts may be driven by servo motors, controlled by remotely located self synchronous transmitting equipment. Also, the mechanical differentials 61 and 98 may be replaced by electromechanical equivalents, wherein shaft 97 is positioned by a servo motor which is controlled by the signal from the self synchronous apparatus. If it is determined, by analyzing equipment not shown, that the target is traveling on a course of curvature Q with a speed of S, rather than on a straight course, the geometry of the problem is changed slightly as illustrated in FIG. 3. Q is the reciprocal of the target turning radius 21, or ' to QSTa where, as before, STa is the distance, or the length of the arc, over which the target travels in elapsed time Ta at a speed S, so that the following equations may be Written: sin cos A cos sin A Substitution of Equations 5 and 6 for the STa cos A and ST a sin A terms respectively in Equations 1 and 2 gives the desired solution for curved course. Thus, in the solution circuit of FIG. 2 the output voltage of rotor windings 37 and 38 of resolver 31 are made proportional in magnitude respectively to the Equations 5 and 6 to provide the cured course solution, as will be described. The STa output voltage of rotor winding 28 energizes the primary winding 151 of induction potentiometer 152, the rotor winding 153 of which is displaced by shaft 154 by an amount proportional to Q, so that the output voltage of secondary winding 153 of potentiometer is proportional in magnitude to QSTa or W. Motor 156 positions shaft 157 according to the output of secondary winding 153 in the usual manner where shaft 157 drives the secondary winding 158 of induction potentiometer 159, the primary winding 160 of which is energized by a constant voltage. The secondary windings 158 and 153 are connected in series with control field winding 161 of motor 156 so that the control field winding 161 is energized by their error voltage. Motor 156 therefore drives winding 158 until the output voltage of winding 158 matches the output voltage of secondary winding 153 so that motor 156 is de-energized and the displacement of shaft 157 from its zero position is proportional to W. Shaft 157 drives the inputs of both cams 162 and 163 the characteristics of which are such that the respective output shafts 164 and 165 are displaced according to the relationships sin W 1cos W (1- W )and Shaft 164 drives the secondary Winding 166 of induction potentiometer 167 while shaft 165 drives the secondary winding 168 of induction potentiometer 169. The primary windings 170 and 171 of respective otentiometers 167 and 169 are energized by the STa output voltage of rotor winding 28 so that the output voltages of secondary windings 166 and 168 are proportional in magnitude, respectively, to sin W l-cos W STa(1 W )and STa(- while the switch 34 is actuated so as to remove the short circuit of primary Winding 35 and to energize said winding by the output voltage of secondary winding 168 which is proportional in magnitude to Since the secondary windings 37 and 38 of resolver 31 are displaced by shaft 39 by an amount proportional 11 to A, the output voltages of secondary windings 37 and 38 are proportional in magnitude,,respectively, to and [STa-STa(1- sin A STa cos A Since these values agree with the right hand side of Equations 5 and 6 respectively, it will be seen that the solution determined by the instrument when the actuator bar 33 is in the left hand position corresponds to curved course travel of the target vessel. It may also occur that the attacking vessel is not traveling on a straight course but is turning with a rate of change of course equal to dCo/dt. Then, in the interval of time Tg between the pressing of the firing key and the uncaging of the gyro the torpedo turns through an angle so that this angle should be applied to the solution angle G. Another correction which is applied to G is the drift, D, of the torpedo or its deviation from a predicted course due to errors of the gyro and steering mechanisms. Tg and D vary for the various types of torpedoes and are introduced to the computer through voltage dividers, in a manner similar to that used for the introduction of the S M, Z and S values. A voltage proportional in magnitude to dCo/dt is de veloped in the usual manner in apparatus not shown here and is applied to the terminals 172, 175 in FIG. 2. The voltage divider 173 is energized by the voltage at terminals 172, 175 and the output of the voltage divider 173 taken across the movable contact 174 of switch 176 and terminals 175 is proportional in magnitude to The constant voltage of transformer 177 energizes the voltage divider 178 and the output of the voltage divider 178, taken across the movable contact 179 of switch 180 and the tap 181 on secondary winding 182 of the transformer 177, is proportional in magnitude to the drift, D, of the torpedo. Movable contact 174 and terminal 175 are connected in series with winding tap 181, movable contact 179, secondary winding 184 of induction potentiometer 185, and the control field winding 186 of motor 187 so that the motor drives shaft 188 to the position where the displacement of shaft 188 corresponds to the algebraic sum of the outputs of voltage dividers 173 and 178, Shaft 188 drives one input of mechanical differential 189, the other input of which is driven by shaft 97 so that the displacement of the output shaft 190 of differential 189 corresponds to a or G the corrected gyro angle. G is displayed on the dial 183. Another feature in the basic solution circuit provides for directing to torpedo ahead of or behind the estimated target position in order to allow counterbalancing the un- .certainties in the estimated target motion. For example, it may be found desirable to direct the torpedo toward point e", in FIG. 1, which is a distance L ahead of the estimated position e. The distance L is known as the linear spread. It will be seen that substitution of the distance (STa-i-L) for the distance STa in Equations 1 and 2 does not change the geometry of the problem. Thus in FIGURE 2 a voltage proportional in magnitude to L is added to the output of potentiometer 27 as will be described. The transformer 191 is energized by the constant alternating voltage of phase 2, while the stationary contacts of multiple selector switch 192 are connected to various taps on the secondary winding 193. The movable contact 194 of switch 192 is connected to the rotor winding 28 of induction potentiometer 27 while one of the taps on secondary winding 193, preferably center tap 195, is connected to the movable contact of switch 32. Thus, the voltage energizing the primary winding 30 of resolver 31 for a straight course is the algebraic sum of the outputs of secondary winding 28 and the output of switch 192, ST a+L, and the solution for G determined by the instrument will be such as to direct the torpedo toward point e". The multiple selector switch 192 allows easy choice of different values of L. In an alternative arrangement, a potentiometer (not shown) may be interposed between primary winding 191 and to provide for continuous variation of the linear spread L. FIGURE 5 shows the computing circuit of FIGURE 2 in simplified form. This single line diagram includes the major components of FIG. 2, and is presented to aid in the discussion of one area of FIG. 2 which requires special attention. These components carry the same numerals as in FIG. 2, and their functions are fully detailed in the description of FIG. 2. Accordingly, it will be seen that the output of resolver 11 is fed through a voltage divider 12, induction potentiometer 27 and resolver 31 back to the input of resolver 11. It has been found in practice that the resolver 11 and its associated booster amplifier (not shown) has a gain of greater than unity for voltages of relatively high frequency, i.e. on the order of 50 kc. per sec. Voltages of this frequency may arise from harmonics in the supply or from stray pickup, and its transmission around the loop in FIG. 5 will produce oscillation in the circuit which impairs or completely destroys the sensitivity of motor 117 to signals of fundamental frequency. In order to eliminate the oscillator voltages, a filter which passes only signals of fundamental frequency is inserted in the U output of resolver 11. If such a filter is composed of static components, the filter will introduce phase shift whenever the signal frequency changes slightly from the nominal value to which the filter is tuned. To the end that the filter is kept tuned to the frequency of the voltage supply the filter is made adjustable and is automatically tuned by a servo which is responsive to quadrature voltage in the filter output. In order to reduce the tendency of the circuit to oscillate and to compensate for the quadrature voltage, the circuit of FIGURE 6 is used to supply the U voltage to voltage divider 12. It is seen from the previous operational description that the voltage output of rotor winding 10 of resolver 11 is elfectively fed to the voltage divider 12a. This connection is shown by the dotted lines in FIGURE 6. However, in practical construction for the purposes of preventing oscillation and reducing quadrature voltage, the circuit of FIGURE 6 is used. The usual amplifiers and damping devices used with motors are not shown since their necessity and operation are well known to those familiar with the art. In FIGURE 6 the output of resolver 11 is fed through filter 208 to the input of the booster amplifier 201. The filter comprises an L-type network having a series resistor 206 in the input branch and with the output taken 13 across the parallel connected capacitor 202 and variable inductance 203. The variable inductance 203 is composed of a fixed inductance 204 and an adjustable inductance 205 connected in series. The variable indutance 205 may be a resolver for example where the primary winding 217 is short circuited. The inductance of the secondary winding 218 will then vary with the coupling between the primary and secondary windings so that by rotating the rotor of the resolver the parallel condenser-inductance circuit of filter 200 can be tuned to the frequency of the signal, nominally 400 cycles/sec, but which may vary from the nominal value by several percent. As the signal to filter 200 is derived from the same source as the two voltages are of the same frequency. The filter 200 is tuned to the nominal supply frequency when the shaft 216 is in the zero position, and the windings 217 and 218 of resolver 205 are uncoupled. If the signal supply is 400 cycles the signal will be transmitted without phase shift through the filter circuit. When the supply voltage varies from the nominal 400 cycles, however, there will be a phase shift of the output of filter 200 with respect to the input by virtue of the fact that considerable phase shift is produced in a resonant circuit for small variations of supply frequency from the resonant frequency. The output of filter 200 is applied to the input terminals of amplifier 201, the output of which is connected in series with the output of rotor winding 20 of potentiometer 19 across the primary winding 207 of transformer 208. Resistor 206, which is employed to magnify the phase shift in filter 200 causes attenuation in the signal so that the booster amplifier 201 is required to compensate for that attenuation. It is assumed that no phase shift is introduced by the amplifier 201. The secondary Winding 211 of transformer 208 is connected through converter 215 to the control field winding 212 of two-phase induction motor 213. Converter 215 is a device of conventional construction which allows only quadrature voltage, i.e. in phase with 4: to be transmitted to the control field winding 212. For example, the converter may include demodulator and modulator means of any well known type, such as typified by Milsom US. Patent 2,557,194 issued June 19, 1951, for example. Since 15 and are in quadrature and the signal to filter 200 is in phase with (p the output of filter 200 is normally in quadrature with Any output from comparator 215 would indicate a phase difference between the filter output and The main field winding 214 of motor 213 is energized by 5 so that motor 213 is energized to drive shaft 216 and the rotor winding 218 of inductor 205 in the direction reducing the quadrature voltage output of filter 200. When the filter 200 is tuned to the supply frequency the quadrature output will be zero so that motor 213 will be deenergized. In this condition, the output of the filter is an in-phase voltage of fundamental frequency from which the undesirable high frequency voltages have been eliminated. It will be seen that an incidental result of this action is to reduce all the quadrature voltage which may be present in the output of resolver 11. The secondary winding 209 of transformer 208 is connected to energize the control field winding 22 of two phase induction motor 18, the main field winding 18 of which is energized by A converter 210 interposed in the connections between windings 209 and 22 transmits only the in-phase component, i.e. in phase with of the output voltage of winding 209. Motor 18 therefore is energized according to the difference between the outputs of amplifier 201 and the secondary winding 20 of induction potentiometer 19 so that motor 18 drives shaft 17 and the rotor winding 20 until the output of the rotor winding 20 matches that of amplifier 201 and motor 18 is deenergized. Thus, either the output of amplifier 1d 201 or potentiometer 19 may be used as the U signa voltage to the voltage divider 12a. Since the amplifier outputis more accurate it is desirable to use that whenever the problem is near solution and to use the potentiometer output only when the solution of the problem is near the outer limits, i.e. when the solution shows a large value of Ta. To this end a switch 219, actuated by a relay 220 which is sensitive to the Ta signal, selects either the output of the amplifier 201 or the potentiometer 19 as the signal which energizes voltage divider 12. The Ta signal may be taken from primary winding 26 of potentiometer 27 (FIG. 2). This arrangement is required since a solution at the .outer limits is not reliable and may in fact be such as to cause regeneration in the purely electrical loop shown in FIG. 5. By using the potentiometer 19 to supply the U voltage to the voltage divider 12 a mechanical system which cannot follow oscillations in the electrical signal is interposed in the loop thereby providing a system which seeks a solution smoothly and quickly. Preferably, motor 18 is generator damped by a generator such as 221 whichis driven by shaft 17 of the motor. The connections of generator 221 are well known and are merely indicated by the dotted lines where the signal from converter 210 is opposed by the signal from the gener- 1 ator 221. When the solution is in range, the system is no longer regenerative and the output of amplifier 201 can be used directly without fear of sustaining oscillation. Thus, when Ta drops low enough, switch 219 is operated to elect the output of amplifier 201 to energize voltage divider 12. We claim: 1. In a device of the character described for regulating the path of a torpedo, a resolver having one winding energized by a voltage proportional to the turning radius of a torpedo and a second winding energized by the sum of the reach of the torpedo and the travel of the torpedo in air, a second resolver energized by the outputs of said first resolver and one of the inputs to said first resolver, a third resolver energized according to distance travelled by own ship and adjusted according to relative bearing, said third resolver having its outputs connected to the outputs of said second resolver, a fourth resolver energized by the combined outputs of said second and third resolvers, motive means controlled by one output of said fourth resolver and adapted to control said second and fourth resolvers, a fifth resolver, the other output of said fourth resolver being connected to energize said fifth resolver, the outputs of said fifth resolver being connected to modify the inputs of said fourth resolver and means adapted to control said first resolver according to the difierence between the adjustment of said second and third resolvers. 2. In a device of the character described for regulating the path of a torpedo, a resolver having one winding energized by a voltage proportional to the turning radius of a torpedo and a second winding energized by the sum of the reach of the torpedo and the travel of the torpedo in air, a second resolver energized by the outputs of said first resolver and one of the inputs of said first resolver, a third resolver energized according to distance travelled by own ship and adjusted according to relative bearing, said third resolver having its outputs connected to the outputs of said second resolver, a founth resolver energized by the combined outputs of said second and third resolvers, motive means controlled by one output of said fourth resolver and adapted to control said second and fourth resolvers, a fifth resolver, the other output of said fourth resolver being connected to energize said fifth resolver, the outputs of said fifth resolver being connected to modify the inputs of said fourth resolver and means adapted to control said first resolver according to the difference between the adjustment of said second and third resolvers, and a quadrature reduction device connected between the output of said fourth resolver and the input of said fifth resolver and including a tunable filter having a variable inductance, means responsive to quadrature component of the output of said filter, a motor energized according to the output of said means and adapted to adjust said variable inductance to reduce said quadrature output. 3. In a device of the character described for regulating the path of a torpedo, a resolver having one winding energized by a voltage proportional to the turning radius of a torpedo and a second winding energized by the sum of the reach of the torpedo and the travel of the torpedo in air, a second resolver energized by the outputs of said first resolver and one of the inputs to said first resolver, a third resolver energized according to distance travelled by own ship and adjusted according to relative bearing, said third resolver having its outputs connected to the outputs of said second resolver, a fourth resolver energized by the combined outputs of said second and third resolvers, motive means controlled by one output of said fourth resolver and adapted to control said second and fourth resolvers, a fifth resolver, the other output of said fourth resolver being connected to energize said fifth resolver, the outputs of said fifth resolver being connected to modify the inputs of said fourth resolver and means adapted to control said first resolver according to the difference between the adjustment of said second and third resolvers, and a quadrature reduction device connected between the output of said fourth resolver and the input of said fifth resolver and including a tunable filter having a variable inductance, converter means responsive to quadrature component of the output of said filter, a motor energized according to the output of said means and adapted to adjust said variable inductance to reduce said quadrature output. 4. In a device of the character described for regulating the path of a torpedo, a resolver having one winding energized by a voltage proportional to the turning radius of a torpedo and a second winding energized by the sum of the reach of the torpedo and the travel of the torpedo in air, a second resolver energized by the outputs of said first resolver and one of the inputs to said first resolver, a third resolver energized according to distance travelled by own ship and adjusted according to relative bearing, said third resolver having its outputs connected to the outputs of said second resolver, a fourth resolver energized by the combined outputs of said second and third resolvers, motive means controlled by one output of said fourth resolver and adapted to control said second and fourth resolver, a fifth resolver, the other output of said fourth resolver being connected to energize said fifth resolver, the outputs of said fifth resolver being connected to modify the inputs of said fourth resolver and means adapted to control said first resolver according to the difference between the adjustment of said second and third resolvers, and a quadrature reduction device connected between the output of said fourth resolver and the input of said fifth resolver and including a tunable filter having a variable inductance, modulator-demodulator means responsive to quadrature component of the output i6 7 6. In a device of the character described, a quadrature reduction device including a tunable filter having an output voltage proportional to that component of the input voltage which is in quadrature with a given reference voltage and having a variable inductance, said variable inductance comprising an electromechanical unit having a primary, or rotor, winding connected to the filter and a shorted secondary or stator winding inductively coupled with said rotor winding, converter means responsive to quadrature component of the output of said filter, a motor energized according to the output of said means and adapted to adjust said rotor winding to reduce s aid quadrature output. 7. In a device of the character described, a quadrature reduction device including a tunable filter having an output voltage proportional to that component of the input voltage which is in quadrature with a given reference voltage and having a variable inductance, said variable inductance comprising an electromechanical unit having a primary, or rotor, winding connected to the filter and a shorted secondary or stator winding inductively coupled with said rotor winding, modulator-demodulator means responsive to quadrature component of the output of said filter, a motor energized according to the output of said means and adapted to adjust said rotor winding to reduce said quadrature output. 8. In a device of the character described for regulating the path of a torpedo, a resolver having one winding energized by a voltage proportional to the turning radius of a torpedo and a second winding energized by the sum of the reach of the torpedo and the travel of the torpedo in air, a second resolver energized by the outputs of said first resolver and one of the inputs to said first resolver, a third resolver energized according to distance travelled by own ship and adjusted according to relative bearing, said third resolver having its outputs connected to the outputs of said second resolver, a fourth resolver energized by the combined outputs of said second and third 1 resolvers, motive means controlled by one output of said fourth resolver and adapted to control said second and fourth resolvers, a differential operatively connected to said motive means and having a second input adjusted according to relative bearing, the output of said differential being adapted to control said first resolver, a fifth resolver, the other output of said fourth resolver being connected to energize said fifth resolver, the outputs of said fifth vresolver being connected to modify the inputs of said 1 fourth resolver and means adapted to control said first air, a second resolver energized by the outputs of said first of said filter, a motor energized according to the output of said means and adapted to adjust said variable inductance to reduce said quadrature output. 5. In a device of the character described, a quadrature reduction device including a tunable filter having an output voltage proportional to that component of the input voltage which is in quadrature with a given reference voltage and having a variable inductance, said variable inductance comprising an electromechanical unit having a primary, or rotor, winding connected to the filter and a shorted secondary or stator winding inductively coupled with said rotor winding, means responsive to quadrature component of the output of said filter, a motor energized according to the output of said means and adapted to adjust sa d rotor winding to reduce said quadrature output. resolver and one of the inputs to said first resolver, a third resolver energized according to distance travelled by own ship and adjusted according to relative bearing, said third resolver having its outputs connected to the outputs of said second resolver, a fourth resolver energized by the combined outputs of said second and third resolvers, motive means controlled by one output of said fourth resolver and adapted to control said second and fourth resolvers, a fifth resolver, the other output of said fourth resolver being connected to energize a potentiometer ad- (References on following page) 17 18 References Cited in the file of this patent 2,402,025 Crooks June 11, 1946 UNITED STATES PATENTS 2,564,682 Fisk 1951 6 2,652,529 Alexanderson Sept. 15, 1953 2,1 2,088 Rmge May 30, 1939 2,766,384 Prewitt Oct. 9, 1956 234 ,933 Greene 4, 1944 5 2,786,183 Jacks Mar. 19, 1957 2,402,024 Crooke June 11, 1946 Patent Citations
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