Patent GB-1314741-A (GB)
Title: Method of controlling motor-driven devices adapted to be directed onto moving targets and apparatus for applying the method
IPC: F41G5/08
Filed: 1970-06-02
Abstract: 1314741 Sighting RHEINMETALL GmbH 2 June 1970 [4 June 1969] 26655/70 Heading F3C  In a method of controlling motor-driven devices mounted on two axes and adapted to be directed on to moving targets, the target being followed by at least one of these devices and the control quantities for the drive of the devices adapted to be directed on to moving targets being calculated by a computer, values are derived continuously from one of the devices adapted to be directed on to moving targets of the lateral angle # and the elevation angle # and values, assumed constant for a given target tracking, of the target velocity v and the angle of inclination # of the target path with respect to the horizontal plane, on the basis of the geometrical relationships which hold true for a rectilinear uniform movement, the lateral angular velocity ## and the elevational angular velocity ##, are calculated and fed to the drives of the devices adapted to be directed onto moving targets. The control quantities for the drive of the devices adapted to be directed on to moving targets is based on a representation of the target motion in polar co-ordinates in a co-tangent plane assumed at constant height, in that, in order to account for the angle of inclination # of the target path the angle # between the projection of the target flight path on the cotangent plane and the projection of the associated horizontal on the cotangent plane ara calculated. The target velocity #-and the angle of inclination # of the target path are estimated. A target acquisition device may be used which is mounted on a gun and participates in the movements thereof. The lateral and elevation lead angles # and Á and the gravity compensation angle α are calculated and the target acquisition device is moved back through these angles #, Á and α with respect to the gun. The quotient of the horizontal component w of the target velocity v and the minimum value #<SP>1</SP> 'min', of the horizontal components of the distance of the target, the quotient being constant for a given tracking operation, is determined from ##= (w/v<SP>1</SP>min). sin <SP>2</SP># by adjusting the calculated value of the lateral angular velocity ## to the value ## of the lateral angular velocity supplied by a manual lever control. The angle # of one of the devices adapted to be directed on to moving targets with respect to the direction of the target path is calculated and the value of the quotient thus determined is used as a basis for the calculation of the lateral angular velocity ## during the further tracking.  In apparatus for carrying out the above method the values of the lateral angle # and the elevation angle # measured at the devices adapted to be directed on to moving targets and the estimated values of the target velocity vg and the angle of inclination # are processed to computing units in accordance with the equations to determine the angles # and # or trigonometrical functions of said angles. In further computing units the elevation angular velocity #γ is determined by the equation #γ o's sin 2γ . cot (# + #) ##. By differentiating the calculated values # of the lateral angle or by forming differences between the calculated values of # the lateral angular velocity ## is determined. By means of computing units the distance v to the target is determined by the equation and that by means of a ballistic computer, taking account of the calculated range v, the gravity compensation angle α and the projectile flight time tG are calculated. From the values of the elevational and lateral angular velocities #γ and ## and from the value of the projectile flight time tG the tangent values of the elevational lead angle Á and of the lateral lead angle # are determined by multiplying computing units in accordance with the equation From these equations the elevation and lateral lead angles Á and # are determined by means of function converters obtaining the inverse tangent. An autocontrol device may be provided which includes a sine squared potentiometer whose resistance varies with the rotation of the slider according to the square of the sine of the angle of rotation and a self-balancing control circuit which swings the slider of the sine squared potentiometer in accordance with the value calculated by the computer of the lateral angle # measured with respect to the projection of the larger path on to the horizontal plane to the resistance value Sin <SP>2</SP># and that in accordance with the equation by means of a second control circuit by adjusting the slider of a current regulating potentiometer, the current flowing through the sine squared potentiometer is set to the value, constant for a given tracking operation, of the   quotient #/# min formed for the horizontal component # of the target velocity v and the minimum value v min of the horizontal component of the target range, said setting being effected by adjusting the voltage tapped from the sine squared potentiometer and corresponding to the lateral angular velocity ## by the voltage value ## of the lateral angular velocities supplied by the control lever and that an integrator is provided, which in accordance with the equation determines the value cot #, from which by means of a function converter the value # may be found. The value # thus found replaces the value of # calculated by the computer when a switch is operated to change from manual control to automatic control. The Specification describes embodiments with reference to the drawings and includes details of a geometrical illustration from deriving the fundamental equations for the method, block circuit diagrams of computers, a block circuit diagram of an adapter device which is connected between the computer and the drive of the weapon or sight, a basic circuit diagram of a control system, and an autocontrol apparatus.