Patent GB-947234-A (GB)
Title: Improvements in electric analogue computers
IPC: G06G7/34
Filed: 1961-04-27
Abstract: 947,234. Electric analogue calculating. COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL, and SOC. MAROCAINE DE RECHERCHES D'ETUDES ET DE DEVELOPPEMENTS SOMAREDE. April 27, 1961 [April 29, 1960], No. 15330/61. Heading G4G. An electric analogue computer for solving systems of nonlinear equations of the type wherein x 1  . . . x q  are q unknowns, comprises manually operable shafts for positionally simulating constant coefficients of the equations; q servomechanisms with output shafts for positionally simulating the respective q unknowns in response to q control voltages; an error calculator comprising quadripole networks controlled by the servomechanism output shafts and the manually operable shafts for calculating error signals (voltage or current) simulating respectively the values of function f 1  wherein i takes values between 1 and p; a translating network, having p inputs receiving the error signals and q outputs delivering control voltages to the servomechanisms, the translating network comprising plural reversible quadripoles having adjustable transfer coefficients controlled by the servomechanism output shafts and the manually operable shafts which are connected between the p inputs and the q outputs in such manner that if voltages U 1  . . . U q  are applied to the q outputs, voltage or current signals appear at the p inputs given by (3) Fig. 1 shows an electric analogue computer of the kind described in Specification 947,233 for solving the simultaneous equations. wherein servosystems G 1 , G 2  produce shaft rotations representing x, y in response to control signals U 1 , U 2  which are applied to error calculator network DC to adjust quadripole voltage transformers 101, 201 and 102, 202, 203 respectively of the kind described in Specification 853,201, all energized from a source S 1  of alternating reference voltage V o , wherein 201, 202 are energized from the output of 101 to yield voltages V o x<SP>2</SP> and V o xy and 203 from the output of 102 to yield V o y<SP>2</SP>. These signals together with signals V o x from 101 V o y from 102 and V o  from S 1  are fed to quadripolar networks 301, 302, 304, 303, 305, 306 manually adjustable by coefficient controls a 1  to a 6  and returned to output SC 1 ; 401, 402, 404, 403, 405, 406 manually adjustable by coefficient controls b 1  to b 6 ; returned to output SC2; with 501, 502, 503, adjustable by controls a 1 , a 2 , a 3 ; 504, 505, 506 adjustable by controls a 2 , a 3 , a 5 ; 601, 602, 603 adjustable by controls b 1 , b 2 , b 4 ; and 604, 605, 606 adjustable by controls b 2 , b 3 , b 5  and returned respectively to the outputs SC 11  to SC 22 . The voltages V o f, V o g on SC 1 , SC 2  thus represent equations (4) and (5) above while the voltages on SC 11  to SC 22  represent (9) g<SP>1</SP>y = (b 2 x + 2b 3 y + b 5 ) the coefficients being set in by the respective manual controls. In quadripolar translating network DR 1 , voltages V o f, V o g energize quadripoles 11, 12 and 21, 22 respectively whose transfer coefficients are respectively adjusted by voltages V o f<SP>1</SP> x , V o g<SP>1</SP>x, V o f<SP>1</SP> y , V o g<SP>1</SP>y and whose outputs are summed in pairs to provide output voltages U 1 , U 2  on lines SR 1 , SR 2  controlling servomechanisms G 1 , G 2  to represent the values of x,y. At equilibrium, balance is achieved and the servomechanisms represent by their shaft rotations the solution of the equations for x and y. As modified according to the present invention (Fig. 2) error calculator network DC comprises source S 1 , quadripoles 101, 102, 201, 202, 203 and servomechanisms G 1 , G 2  arranged as in Fig. 1 supplying voltages V o x<SP>2</SP> to quadripoles 301, 401 adjusted by controls a 1 ,b 1 ; V o xy toquadripoles 302, 402 adjusted by controls a 2 , b 2 ; V o x to quadripoles 304, 404 adjusted by controls a 4 , b 4 , V o y<SP>2</SP> to quadripoles 303, 403 adjusted by controls a 3 , b 3 ; V o y to quadripoles 305, 405 adjusted by controls a 5 , b 5 ; and V o  to quadripoles 306, 406 adjusted by controls a 6 , b 6 . The outputs of quadripoles 301 to 306 and 401 to 406 are combined on lines SC 1 ,SC 2  to represent equations (4) (5) by voltages V o f, V o g. Quadripolar translating network DR comprises quadripoles 701 to 705 and 712 adjusted by controls a 1  to a 5  and quadripoles 801 to 805 and 812 adjusted by controls b 1  to b 5 ; energized in respective groups from lines SC 1 , SC 2  by voltages V o f and V o g of which 701, 801 energize quadripole 111; 702, 802 energize quadripole 113; 704, 804 energize the output line SR 1  in conjunction with the outputs of quadripoles 111, 113; 712, 812 energizes quadripole 112; 703, 803 energize quadripole 114, and 705, 805 energize the output line SR 2  in conjunction with the outputs of quadripoles 112, 114. It is then shown that if U 1 , U 2  are the voltages on SR 1 , SR 2  and Vof, Vog are the voltages on ER i , ER 2 , and so that and since the quadripoles are all reversible, the voltages V o f, V o g appear on the inputs SC 1 , SC 2  and the voltages U 1 , U 2  appear on the outputs SR 1 , SR 2 . For small errors dx, dy between the computed values of x, y and the solutions x o , y o  of equations (4) and (5) and so that U 1 , U 2  drive servosystems G 1 , G 2  to restore equilibrium at which the solutions x o , y o  are represented by the shaft rotations of the servomechanisms. In a modification (Fig. 3 not shown) sets of voltage to current transformers of the kind described in Specifications 703,178 and 947,233 are inserted between the outputs of quadripoles 301 to 306 and 401 to 406 and lines SC 1 , SC 2 ; and also between lines ER 1 , ER 2  and quadripoles 701 to 705 and 801 to 805. In a further modification (Fig. 4 not shown) the error calculator network and quadripolar translating network are divided into sub-assemblies comprising a servomechanism and several quadripoles for each unknown, controlled by voltages U 1 , U 2  and deriving voltages representing the required functions of the unknowns; a parameter unit for each coefficient of the equations comprising manually adjustable quadripoles for introducing the required coefficients; a connector unit for each parameter unit receiving the analogue voltages of the unknowns from the servomechanism/ quadripole units, transmitting them to the appropriate parameter units, receiving therefrom the analogue voltages of the respective monomials of the equations, and deriving therefrom the voltage analogues of the differentials of the respective monomials, which are combined in equation synthesising units to develop control voltages U 1 , U 2  for transmission to the servomechanisms as in Fig. 2. The several units are connectible by plugs, sockets and prefabricated cable harnesses (Fig. 5 not shown). The connector units may be modified to introduce summation, squaring, multiplying, cubing, dividing, trigonometrical and unspecified functions (Figs. 6-15 not shown) into the synthesis of the required equation monomials, utilizing further addition circuits and variable transfer characteristic quadripoles in appropriate combination. The connector units and parametric units may be combined in composite units as required. In a further modification (Fig. 18) a servomechanism multiplier unit SM x  comprises a servomotor G x  responsive to an input signal #x controlling a quadripolar transformer yielding a voltage representing x. Two other quadripoles energized by x and dx signals are driven by the servomotor to yield signals representing xdx and x<SP>2</SP> (Fig. 16 not shown), while a servomultiplier circuit (Fig. 17 not shown) produces a signal representing xdx which is added to the similar quadripole signal to produce 2xdx. A similar servomultiplier SM y  produces signals representing y<SP>2</SP> and 2ydy and the servomotor also drives further quadripoles energized with x signals to produce xy and ydx signals. The latter is summed with the output of the product of dy and s signals to produce a (ydx + dy) signal. The signals are selectively connected over plugs and sockets and a cable harness (Fig. 19 not shown) to two ranges of parametric units SPa 1  to as and SPb 2  to 6b 6  whereby coefficients a 1  to a 6  and b 2  to b 6  are Introduced by manual controls adjusting multiplying quadripoles whereby ranges of signals representing a 1 x<SP>2</SP>, a 2 xy, a 3 y 2 , a 4 x 1 , a 5 y, a 6  and 2 a1 xdx a 2 (ydx + xdy), 2a 3 ydy, a 4 dx, a 5 dy are added in respective circuits of equation unit E 1  while ranges of signals representing b 1 x<SP>2</SP>, b 2 xy, b 3 y 2 , b 4 x, b 5 y, b 6  and 2b 1 xdx, b 2 (ydx + xdy), 2b 3 ydy, b 4 dx, b 5 dy are added in respective circuits of equation unit E 2  to synthesise the equations (4), (5) in f and g and also equations in f<SP>1</SP>g<SP>1</SP> so that for equilibrium. and the outputs of servomotors E x E y  represent the independent variables x, y for solution of the equations. In modifications the parametric units and equation units may be combined (Fig. 20 not shown) the pairs of monomials and derivative voltages fed to each parameter unit may be added and together multiplied by the required coefficient for application to the appropriate equation unit (Fig. 21 not shown) or the servomechanism units may be modified to introduce summing, multiplying, cubing, dividing, trigonometrical, and unspecified functions of the independent variables and their derivatives into the system (Figs. 22, 23, 24,25, 26, 27, 28 (not shown).