Patent GB-1108904-A (GB)
Title: Analogue computers
Inventor: NORONHA LEONARDO GASTAO
IPC: G06G7/122
Filed: 1965-09-16
Abstract: 1,108,904. Mixture compounding computer. ELECTRONIC ASSOCIATES Ltd. 13 Sept., 1966 [16 Sept., 1965], No. 39660/65. Heading G4G. A computer for compounding mixtures of proportions x 1 , x 2 , x 3  of ingredients X 1 , X 2'  X 3  for minimum cost C and containing constituents F 1 , F 2  in proportions f 1 , f 2  wherein and wherein the costs per unit weight of ingredients X 1 , X 2 , X 3  and their proportions of constituents F 1  F 2  are given by comprises (Fig. 1) conductors 11, 12, 13 carrying proportional analogue voltages x 1 , x 2 , x 3  and connected through constituent potentiometers 16, 17, 18 introducing coefficients f 11 , # 21 ,# 31  to amplifier 14; and through constituent potentiometers 19, 20, 21 introducing coefficients # 12 , # 22 , # 32  to amplifier 15. The output (-# 1 ) of amplifier 14 represents # 11 x 1  + # 31 x 2  + # 31 x 3  (1) and that of amplifier 15 # 2  represents # 12 x 1  + # 22 x 2  + # 32 x 3  (2), which are applied to error units 22, 23 (Fig. 2) respectively supplied with upper and lower limit voltages representing F 1  max, F 1  min and F 2  max, F 2  min to yield error voltages 2K 1 E 1 ; 2K 1 E 2 . Fig. 2 shows error unit 22 comprising summation amplifiers 34, 35 of gain (- 2K 1 ) receiving positive voltages analogous to F 1  max and F 1  min over constraint potentiometers 37, 38 and analogue voltage (-# 1 ) from amplifier 14 over normally closed switches 39a, 40a. The outputs are connected over diodes 41, 43 and normally closed switches 39b, 40b ganged for operation with switches 39a, 40a to the inputs of amplifier 36, and the outputs are also back connected over diodes 42, 44 to summing inputs of the amplifiers 34, 35. For imposing an equality constraint, the switches are opened so that an error output is produced whenever the input differs from the value set up by potentiometer 37. Error unit 23 is similar, utilizing constraint potentiometers 45, 46. The error voltages are given by The voltage analogues of x 1 , x 2 , x 3 , are added in amplifier 24 to give (- t) output where t = x 1  + x 2  + x 3  applied to a further error unit (Fig. 3, not shown) comprising a high gain amplifier receiving a fixed reference voltage to produce an output E T  given by E T  = 1 - (x 1  + x 2  + x 3 ). (4) Summing integrators 26, 27, 28 energizing conductors 11, 12, 13 with analogue voltages x 1 , x 2 , x 3  are guarded against negative outputs by series assisting diodes 261, 271, 281 and feedback opposing diodes 26<SP>11</SP>, 27<SP>11</SP>, 28<SP>11</SP>, and receive the analogue voltages E T  directly; 2K 1 E 1  over respective error matrix potentiometers 16<SP>1</SP>, 17<SP>1</SP>, 18<SP>1</SP>, introducing coefficients # 11 , # 21 ,# 31  and 2K 1 E 2  over respective error matrix potentiometers 19<SP>1</SP>, 20<SP>1</SP>, 21<SP>1</SP> introducing coefficients # 12  # 22 , # 32 . The integrators also receive a reference voltage K 2  from source 29 over respective cost potentiometers 30, 31, 32 introducing coefficients c 1 , c 2 , c 3 , and consequently represent equations A summing amplifier 33 receives analogue voltages x 1 , x 2 , x 3  over respective cost potentiometers 30', 311, 321 introducing coefficients c 1 , c 2 , c 3  to produce output - C where C = x 1 c 1  + x 2 c 2  + x 3 c 3  representing cost per unit weight of a mixture of x 1  x 2 , x 3 . In operation, the requisite coefficients of the problem are set into the potentiometers, and when a steady state has been reached the error signals tend to zero and the voltages x 1 , x 2 , x 3 , f 1 , f 2  represent the proportions of the required mixture of ingredients X 1 , X 2 , X 3  and the proportions # 1 ,# 2  of constituents F 1 , F 2  as required. Potentiometers 16, 16<SP>1</SP>; 17, 17<SP>1</SP>; 18, 181; 19, 19; 20,20<SP>1</SP>; 21,21<SP>1</SP> may be ganged in pairs. The computer may be expanded (Fig. 4, not shown) to accommodate up to 30 ingredients and twenty constituents; the relevent input controls being arranged on a control console provided with a switchable digital voltmeter and print out typewriter, and the potentiometers may be provided with course and fine scale changing devices. The limit voltages may be derived from slow ramp function generators so that the mode of variation of minimum cost with variation of the limits may be observed. The ganged pairs of potentiometers, the integrators, amplifiers and error units may be arranged as interchangeable modules. The apparatus is particularly applicable to the compounding of grain mixtures.