US3443476A

US3443476A - Control system for rotatable gun platform and optical sight

Info

Publication number: US3443476A
Application number: US577122A
Authority: US
Inventors: Helmut Heider; Helmut Looss
Original assignee: Licentia Patent Verwaltungs GmbH
Current assignee: Licentia Patent Verwaltungs GmbH
Priority date: 1965-09-01
Filing date: 1966-09-01
Publication date: 1969-05-13
Anticipated expiration: 1986-05-13

Description

May 13, 1969 H. HEIDER ET AL 3,443,476

CONTROL SYSTEM FOR ROTATABLJE GUN PLATFORM AND OPTICAL SIGHT Filed Sept. 1. 1966 +15% AMPLIF R Ia IE BALLISTIC nom pg COMPUTER V l/ SIGNAL SERVOMOTOR l3 GENERATOR RATE OF TURN SIGNAL GENERATOR octoct SERVOMOTOR l6 SIGNAL GENERATOR I5 SIG NAL AMPLIFIER l8 GENERAmR 4 IaALLIsTIc nom mm 4 2 COMPUTER l E I7 -A-'Inm ,1

SERVOMOTOR l3 AMPLIFIER IS;

Pnom RATE OF AMPLIFIER 2o TURN SIGNAL GE SERVOMOTOR l6 RATE GYRO 2V INVENTORS FIG.2.

Helmut Heider 8| Heimut Looss ATTORNEYS 3,443,476 Patented May 13, 1969 Int. Cl. r41 /06 US. Cl. 89-41 6 Claims ABSTRACT OF THE DISCLOSURE A control system for use with a rotatably mounted gun platform which carries a gun and an optical sight, the latter being rotatable on the platform with respect to the gun. The control system includes two se-rvomotors, one for turning the sight with respect to the gun and the other for turning the platform, and two control circuits whose outputs are applied to the respective servomotors. The first control circuit compares a signal representing the nominal value of the lead angle between the optical axis of the sight and the bore axis of the gun with a signal representing the actual instantaneous angle between the optical axis of the sight and the bore axis of the gun, and forms a difference signal which is applied to the first-mentioned servomotor. The second control circuit derives a positioning signal from a nominal value which is a function, with reversed algebraic sign, of the actual rate of turn of the sight, a nominal value which is a function of a predetermined rate of turn, and a signal which is a function of the actual rate of turn of the platform, this positioning signal being applied to the other servomotor.

The present invention relates to a control system for a gun and gun sight arrangement in which the gun is mounted on a movable platform and the gun sight is movable with respect to the gun, wherein a control circuit for controlling the turning of the platform is given a signal representing a predetermined rate of turn.

When a gun is trained on a moving target, the latter is normally observed through an optical sighting device hereinafter referred to simply as a sightwhich is coaxial with the gun, the gun and the sight being kept trained on the target by the application of a signal which keeps the gun turning at the proper rate. If the gun and the sight are on a common platform, for example, the turret of a tank, and if both are aimed by adjusting the azimuth and elevation of the base, the correctional angles, such as lead and elevational angles which are determined, for example, by a ballistic computer, can be set only by changing the position of the sight with respect to the gun. In this way, the gun remains trained on the target while the line of sight, i.e., the optical axis of the sight, is moved off target, and this means that the sight has to be adjusted to remain trained on the target. Thus, by using the correction angles, the sight is first displaced with respect to the gun, after which the sight is again brought into alignment with the target due to the turning of the gun. This type of aiming is known as forming a dependout line of sight. In practice, this type of aiming makes it difiicult to keep the gun trained on the target, and also makes it difficult to track a moving target. For this reason, too, the time interval between the instant the target is first acquired and the firing command can be given is relatively long.

It is, therefore, the primary object of the present invention to provide a sight control arrangement which is simpler, more accurate and faster-responding than the above-mentioned type of arrangement.

More particularly, it is the object of the invention to provide a system in which the steps that have to be carried out to aim the gun are carried out not sequentially, as was heretofore the case, but simultaneously.

Basically, the main difficulty involved in carrying out the step simultaneously is that both a correction angle and a rate are needed in order to carry out the aiming steps simultaneously. Accordingly the present invention resides in a control system incorporating two control circuits, one of which compares a signal representing the nominal value of the lead angle with a signal representing the actual instantaneous angle between the optical axis of the sight and the bore axis of the gun and forms a difference signal which is used to position the sight. The other control circuit derives a setting signal for the platform from a nominal value which is a function, with reversed algebraic sign, of the actual rate of turn of the sight, a nominal value which is a function of a predetermined rate of turn, and a signal which is a function of the actual rate of turn of the platform.

With a ballistic correction angle being given, when a gun is aimed in accordance with the present invention, the sight is turned while at the same time the platform is rotated in the opposite direction and at the same rate. In this way, the optical axis of the sight remains trained on the target while the gun is rotated with respect to the sight throughout an angle corresponding to the ballistic correction angle. In the case of the so-called independent sight, therefore, the sight does not have to be adjusted after the gun has been trained on the target.

According to a further feature of the present invention, the simultaneous displacement of the sight with respect to the platform and the displacement of the platform with respect to the target is improved by providing an auxiliary control circuit for the first control circuit, i.e., the control circuit which provides a signal for positioning the sight. The auxiliary circuit produces a positioning signal for the sight by comparing the actual rate of turn of the sight with the difference of the angular displacement of the sight which is a function of the angle of the displacement, the latter being a control signal which is dependent on the rate of turn of the sight. The last-mentioned difference, after change of the algebraic sign, and a predetermined nominal rate of turn for the platform, are used to form a signal for turning the platform.

Additional objects and advantages of the present invention will become apparent upon consideration of the following description when taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a block diagram of one embodiment of a control system according to the present invention.

FIGURE 2 is a block diagram of another embodiment of a control system according to the present invention.

Referring now to the drawings and first to FIGURE 1 thereof, the same shows a weapon such as a gun 10 and an optical sight 11, both being mounted on a common platform 12. The sight 11 can be turned with respect to the gun 10 and the platform 12 by means of a servomotor 13, the angle between the bore axis 10a of the gun 10 and the optical axis 11a of the sight 11 being reflected by a signal generator 14 which is mechanically coupled to the servo motor 13 and which puts out a signal that is a function of the angle between the axes 10a and 11a. The rate at which the sight 11 is turned is measured by a further signal generator, such as a tachometer-type generator 15. The platform 12 is rotated by means of a further servomotor 16, the rate at which the platform turns being sensed by a rate gyro 21. The further component parts of the system will be described as the operation is explained.

A ballistic computer 17 determines a correction angle Atp and applies the same as a nominal value signal -A p to the first control circuit. This nominal value is compared with the actual angle Age formed between the bore axis a of the gun 10 and the optical axis 11a of the sight 11, the signal representing this angle A being put out by the signal generator 14. The difference between these two values is amplified by an amplifier 18 and applied to the servomotor 13 such as to turn the sighting 11 until the difference is equal to zero. At the same time, the signal A o which is the first derivative with respect to time of the signal A o and hence a signal which is a function of and represents the rate at which the sighting device 11 is turned, is taken off the signal generator 15 and, after inversion of the algebraic sign, applied to a second control circuit, where it is added to a signal representing a predetermined angular velocity or rate of turn to, the same being determined by the marksman in command of the gun and produced by an appropriate signal generator 17a. This value is compared with the actual rate (w+A sensed by the rate gyro 21, at which the platform 12 turns. If the signals are dissimilar, a setting signal is applied to the servomotor 16 via a further amplifier 20, and the platform 12 continues to turn until the difference between the signals becomes zero.

The algebraic sign of the correction signals are such that the sight 11 is turned with respect to the gun 10 throughout an angular distance corresponding to the determined correction angle, while simultaneously the platform 12 carrying the gun 10 and the sight 11 is turned in the opposite direction throughout the same angular distance so that, with respect to the target, the optical axis of the sighting device 11 remains stationary and the bore axis of the gun is turned through'the correctional angle.

The embodiment shown in FIGURE 2 differs from that of FIGURE 1 in that the first control circuit, which is a positional control circuit, has associated with it an auxiliary control circuit in the form of a speed control circuit. The amplified signal representing the angular difference between the sight 11 and the gun 10, which is put out by the amplifier 18, serves as the nominal value A for the rate of turn of the sight 11 with respect to the platform 12, this nominal value being compared with the actual rate of turn (-A ,5 taken off the signal generator 15. The difference between the two values is applied, via an amplifier 22, to the servomotor 13. At the same time, the predetermined rate of turn A p' for the sight 11 is, after inversion of the algebraic sign, in the amplifier 19, applied to the second control circuit and is added to the predetermined rate of turn w of the platform. Both values are compared with the actual rate of turn (w[Ao) which is taken off the rate gyro 21. Any difference is amplified by amplifier as applied to the servomotor 16.

The arrangement shown in FIGURE 2 improves the simultaneous displacement of the sight 11 and the common platform 12. In practice, the dynamics of the auxiliary control circuit and that of the second control circuit should be the same so as to achieve the desired simultaneity and therefore particularly precise sighting and aiming.

Each of the individual components incorporated in the control systems according to the present invention is, per se, known in the art. The rate of turn signal generator 17a is formed, for example, by a potentiometer, by the means of which a variable voltage can be produced. The handle of this potentiometer not shown here will be moved by the gunner correspondingly to the desired value of nom- The present invention is applicable for multiple-axis control, that is to say, separate control circuit systems can be provided for controlling both azimuth and elevation.

What is claimed is:

1. In combination with a gun platform which is rotatably mounted on a base, a gun which is mounted on said platform for rotation therewith, and an optical sight which is also carried on said platform but which is rotatable with respect to the gun, a control system comprising, in combination:

(a) a first servomotor for turning the sight with respect to the gun;

(b) means forming a first control circuit for comparing a signal representing the nominal value of the lead angle between the optical axis of the sight and the bore axis of the gun with a signal representing the actual instantaneous angle between the optical axis of the sight and the bore axis of the gun and for forming a difference signal, the latter being applied to said first servomotor;

(c) a second servomotor for turning the platform; and

(d) means forming a second control circuit for deriving a positioning signal from a nominal value which is a function, with reversed algebraic sign, of the actual rate of turn of the sight, a nominal value which is a function of a predetermined rate of turn, and a signal which is a function of the actual rate of turn of the platform, said positioning signal being applied to said second servomotor.

2. The combination defined in claim 1 wherein said first control circuit comprises:

(1) a first signal generator for producing a signal which is a function of the angle between the optical axis of the sight and the bore axis of the gun;

(2) a ballistic computer for giving a nominal angle which is a function of a predetermined correction angle; and

(3) means for producing an amplified difference between the outputs of said first signal generator and of said computer and for applying the same to said first servomotor.

3. The combination defined in claim 2 wherein said second control circuit comprises:

(4) a second signal generator for producing a signal which is a function of the rate at which the sight is turned;

(5) means for producing a signal which is a function of a predetermined rate of turn;

(6) a rate gyro for producing a signal which is a function of the actual rate of turn of the platform; and

(7) means for adding the outputs of said second signal generator and of said means defined in paragraph (5), and for producing an amplified difference between the thus-obtained sum and the output of said rate gyro and applying such difference to said second servomotor.

4. The combination defined in claim 1 wherein said first control circuit includes a main circuit and an auxiliary circuit, the latter being a means for comparing the actual rate of turn of the sight with the difference of the angular displacement of the sight which is a function of the angle of the angular displacement, the latter being a control signal which is dependent on the rate of turn of the sight, said last-mentioned difference, after change of algebraic sign, and a predetermined nominal rate of turn for the platform, being used to form a signal for turning the platform.

5. The combination defined in claim 4, wherein said first control circuit comprises:

(2) a ballistic computer for giving a nominal angle which is a function of a predetermined correction angle;

(3) means for producing an amplified difference between the outputs of said first signal generator and of said computer;

(4) a second signal generator for producing a signal which is a function of the rate at which the sight is turned; and

(5) means for producing an amplified difference between the outputs of said means defined in paragraph ference between the thus-obtained sum and the out- (3) and said second signal generator and for applyput of said rate gyro and applying the last-mentioned thE same to 531d first Servomotofdifference to said second servomotor.

6. The combination defined in claim 5 wherein said second control circuit comprises: References Cited (6) means for producing a signal which is a function 5 UNITED STATES PATENTS of a predetermined rate of turn,

(7) a rate gyro for producing a signal which is a 3,309,963 3/ 1967 Salomonssonfunction of the actual rate of turn of the platform; d 10 BENJAMIN A. BORCHELT, Primary Examiner.

(8) means for adding the amplified output of said 3 BENTLEY Assistant Examiner.

means defined in paragraph (3), with reversed algebraic sign, to the output of said means defined in X- paragraph (6), and for producing an amplified dif- 318-448 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,443 ,476 May 13 1969 Helmut Heider et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading to the patent, line 9, "P 1,270" should read P 12 7O 449.3-15

Signed and sealed this 24th day of February 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. E.

Attesting Officer Commissioner of Patents