Patent GB-1064774-A (GB)
Title: Weapon firing control system
IPC: G06G7/80
Filed: 1964-06-19
Abstract: 1,064,774. Control systems. BOFORS A. B. June 19, 1964 [July 1, 1963], No.25569/64. Heading G1N. A weapon V, Fig. 1, is aimed by an elevation controlling servomotor S4 and an azimuth controlling servomotor S3, each motor being operated by the sum F4, F3 of a pair of signals, one signal of each pair representing the difference in elevation and azimuth respectively between the weapon and a sighting means S controlled by servomotors S2, S1 respectively; and the second signal of each pair, which corrects for parallax, wind and target speed, etc., #H and ## respectively, being a trigonometrical function of the angle between the sighting means and a reference direction (e.g. angle # to the fore and aft-axis of a ship, and angle H to the horizontal). The angular positions of the weapon V and the sight S in the planes of elevation and azimuth are compared by feeding the angular positions of the servomotors S1, S2, S3, S4, to resolvers R1, R2, R3, R4 (having 2-phase windings), or synchros (having 3-phase windings) or potentiometers, the signal representing the azimuth difference being supplied to amplifier F3, and the signal representing the elevation difference to amplifier F4. The resolvers, &c., may drive through a gear train a further set of resolvers to increase the accuracy of the system. The position of the sight may be stabilized against roll, pitch and yaw, of the ship by mounting two angular velocity sensitive gyros G1 and G2 on the sight and feeding back their outputs to the driving circuits for servomotors S 1 , S 2 . The sight S follows the target either automatically by radar or optical techniques; or by manual control from a control rod 3, which is movable in two mutually orthogonal directions thereby varying the voltages supplied respectively by potentiometers P 1  and P 2  to the servomotors S 1  and S 2 . The outputs of P 2  and P 1  are proportional to the angular speed of the target, about respectively the elevation axis of the sight, and the axis which is perpendicular to both the elevation axis and the line of sight. These voltages are applied also to a computer circuit, together with signals from the resolvers representing the sine and cosine of the elevation and azimuth angles of the target. A circuit Fig. 2 (not shown) includes a 3- to 2-phase transformer, T 1  deriving sine and cosine signals from a system which uses synchros instead of resolvers. The computer circuit includes:- (a) potentiometers P2, P 5  the output of which is proportional to the range L of the target as set manually or measured by radar or optical means and set automatically; (b) potentiometers P 4,  P 6 similarly controlled to be proportional to 1/L; (c) potentiometers P 7 , P 8  manually or automatically set to give an output proportional to the speed F of the ship; (d) a potentiometer P 10  geared to the servomotor S 2  to give an output proportional to the elevation H of the sight; (e) a potentiometer P 9  similarly geared and giving an output proportional to 1 /COS H; (f) amplifiers F 5  to F 10  which introduce proportionality factors to allow, for example, for parallax and projectile velocity. The two outputs of the computer supply the correction signals #H, ##, to the amplifiers F 3  and F 4 . The signal #H comprises four components, in terms of F, L, H, COS # and COS H, and the speed of elevation of the target, and these correct for parallax, ship speed, target speed and gravity effects on the weapon. The signal ## comprises three components, in terms of F, L, Sin # and the horizontal speed of the target, and these correct for parallax, wind speed, and target speed.