Method of controlling photographic emulsion manufacturing process by non-linear approximation

Claim 1

A method of controlling the preparation of a photographic emulsion containing silver halide crystals in a system, by measuring process variables in said system and applying a non-linear approximation of said variables to said system in order to control the system by attaining predetermined process variable values by: (a) inputting into an arithmetic control unit: (1) a set U m (k) of a plurality of process input variables, comprising a flow rate of silver nitrate, (2) a set Y m (k) of a plurality of target process output values, comprising a silver potential and pH value, and (3) a set X(k) of a plurality of state quantity signals, comprising silver halide concentration, from a system model; (b) generating from said inputs, a set U(k) of manipulated variables and applying the same to the emulsion preparation in said system to maintain controlled variables of said system, which comprises silver concentration or potential in solution, and pH, at substantially constant levels, (c) obtaining output process variables Y(k) from said system, which comprise silver concentration or potential in solution, and pH, (d) inputting: (1) said output process variables Y(k) from said system, and (2) said output variables U(k) from said arithmetic control unit into a system model, which model generates a plurality of state quantity signals X(k) which is then applied to said arithmetic control units; (e) generating a controlled value feedback matrix, F b , in a feed-forward matrix from a difference between target values and plant output values which matrix is then used to minimize an evaluation function J(k); (f) calculating from said minimized evaluation function, manipulated variables which are then applied to said system, whereby correlations are made to inputs in said system, thereby effecting multivariable control of said emulsion preparation, and the growth of said silver halide crystals therein.

Claim 2

A method of controlling the preparation of a photographic emulsion containing silver halide crystals in a system, by measuring process variables in said system and applying a non-linear approximation of said variables to said system in order to control the system by attaining predetermined process variable values by: (a) inputting into an arithmetic control unit: (1) a set U m (k) of a plurality of process input variables, comprising a flow rate of silver nitrate, (2) a set Y m (k) of a plurality of target process output values, comprising a silver potential and pH value, and (3) a set X(k) of a plurality of state quantity signals, comprising silver halide concentration, from a system model; (b) generating from said inputs, a set U(k) of manipulated variables and applying the same to the emulsion preparation in said system to maintain controlled variables of said system, which comprises silver concentration or potential in solution, and pH, at substantially constant levels, (c) obtaining output process variables Y(k) from said system, which comprise silver concentration or potential in solution, and pH, (d) inputting: (1) said output process variables Y(k) from said system, and (2) said output variables U(k) from said arithmetic control unit into a system model, which model generates a plurality of state quantity signals X(k) which is then applied to said arithmetic control units; (e) generating a controlled value feedback matrix, F b , in a feed-forward matrix from a difference between target values and plant output values which matrix is then used to minimize an evaluation function J(k); (f) calculating from said minimized evaluation function, manipulated variables which are then applied to said system, whereby correlations are made to inputs in said system, thereby effecting multivariable control of said emulsion preparation, and the growth of said silver halide crystals therein.