Patent GB-793374-A (GB)
Title: Electromechanical double time integrating unit, a computer for solving differential equations comprising such units, and apparatus comprising such units for simulating the movements of a body in flight
IPC: G06G7/78
Filed: 1955-06-02
Abstract: 793,374. Warfare teaching. GIRAVIONS DORAND. June 2, 1955 [June 4, 1954], No. 15873/55. Class 119 [Also in Groups XXXV. XXXVI and XXXVIII] Apparatus for computing the double integral of a function with respect to time and applicable to apparatus for training guided missile operators comprises a rectangular moving coil of substantial moment of inertia energized by the voltage analogue of the function to rotate without friction or control torque in the field of opposed poles of a cylindrical armature surrounding the moving coil, and energized from a constant voltage source so that the moving coil receives a torque proportional to the analogue voltage giving it a proportionate uniform angular acceleration, which due to the interaction of the magnetic fields is also imposed on the armature whose angular displacement is shown to be'proportional to the double integral of the input function; there being provided a follow up system responsive to angular displacement beween the moving coil and the armature to restore angular coincidence therebetween when a fixed small mutual angular displacement is exceeded. If x is the angular displacement, x the angular velocity, and x the angular acceleration of the coil with respect to a datum, due to analogue voltage e, I is the moment of inertia of the coil assembly, C is a constant and M is the torque applied to the coil. Fig. 5 shows apparatus incorporating computer units as described for simulation of the behaviour of a ground to ground guided missile directed towards a target by an operator. A film showing target movements against a stationary background is projected on a screen 88, while an illuminated spot 90 from a projector 91 mounted on gimbals 93 represents the visible flame or tracer of the missile. A control column 87 operable along x and y co-ordinates to simulate corresponding control effects on the missile is linked along mutually perpendicular rods 108, 113 to vary resistances 107, 112 in series with constant D.C. sources and respective range resistances 109, 111 varied through rack and pinion gear by motor 114 controlled by means (not shown) whereby its angular rotation is a function of the speed of the projectile at any instant. The respective series resistance systems are connected over slip rings 103, 104 to the moving coils of double integranting units 99, 100 (see Group XXXVI), the voltages thereof representing the accelerations along rectangular axes perpendicular to the missile path produced by corresponding operation of the control column. Armature angular displacements of the units representing the respective integrated instantaneous displacements of the simulated missile divided by its instantaneons range (i.e. to its integrated angular deflectioins) are connected over respective linkages 96, 97 to control the elevation and azimuth deflections of projector 91 so that the position of spot 90 moves similarly to the angular position of an actual missile as seen from the firing point; the object of the operator being to achieve coincidence between the light spot and the moving target when they are both at the same simulated distance from the operator; the target and spot movements then being arrested by means not shown.