Furnace temperature control apparatus using adjustment input

Claim 1

A furnace temperature control apparatus for controlling inside temperatures (y) at selected points of a furnace having heaters so as to repeatedly run the furnace in a certain operating pattern of temperature change with time, said apparatus comprising: a preset value memory storing preset temperature values (r) of the operating pattern for certain points in the furnace; sensors measuring the inside temperature (y); an output memory connected to the sensors to store measured inside temperatures (y); a controller adapted to generate output signals to the heaters in response to simultaneous application of said inside temperatures (y) and at least one of the preset temperature values (r) and adjustment input (r) to the controller, said output signals from the controller forming at least a part of manipulating variable signals (u) applicable to the heaters of the furnace; an enlarged system including said furnace and said controller; an adjustment input memory adapted to store the adjustment input (r) for each cycle of said repetition, and connected to at least one point of the enlarged system so as to apply the adjustment input (r) thereto in synchronism with the application of the inside temperatures (y) to the controller; an adder connected to the preset value memory and the output memory so as to determine errors (e) between the preset temperature values (r) and latest inside temperatures (y); a dual system model with respect to said enlarged system being connected to said adder and disconnected from the preset temperature values (r); and an adjustment input generator connected to both the dual system model and the adjustment input memory so as to renew the adjustment input (r) based on a combination of the adjustment input (r) values in preceding cycle of said repetition and output (v) from the dual system model in response to application of the errors (e) thereto.