Control system for plant

A control method for a plant, the method comprising:

• calculating a feedback control input so that a controlled output of said plant coincides with a target value;
• calculating a hold control input according to a parameter indicative of the controlled output of said plant, the hold control input being a control input for maintaining a control deviation between the controlled output and the target value at a value equal to or less than a predetermined threshold value when the target value is maintained at a constant value;
• setting a control input to the feedback control input of said plant, when the control deviation between the controlled output and the target value is greater than the predetermined threshold value, and setting the control input to the hold control input, when the control deviation is equal to or less than the predetermined threshold value;
• and
• controlling the feedback control input to gradually approach to or coincide with the hold control input, when the control input is set to the hold control input.

A computer program embodied on a computer-readable medium for causing a computer to implement a control method for a plant, the control method comprising:

• calculating a feedback control input so that a controlled output of said plant coincides with a target value;
• calculating a hold control input according to a parameter indicative of the controlled output of said plant, the hold control input being a control input for maintaining a control deviation between the controlled output and the target value at a value equal to or less than a predetermined threshold value when the target value is maintained at a constant value;
• setting a control input to the feedback control input of said plant, when the control deviation between the controlled output and the target value is greater than the predetermined threshold value, and setting the control input to the hold control input, when the control deviation is equal to or less than the predetermined threshold value;
• and
• calculating the feedback control input to gradually approach or coincide with the hold control input, when the control input is set to the hold control input.

A control system, comprising:

• a feedback controller configured to calculate a feedback control input such that a controlled output of a plant coincides with a target value;
• a hold control input calculator configured to calculate a hold control input according to a parameter indicative of the controlled output of the plant, the hold control input being a control input for maintaining a control deviation between the controlled output and the target value at a value equal to or less than a predetermined threshold value when the target value is maintained at a constant value;
• and
• a control input setting unit configured to set a control input to the feedback control input of the plant, when the control deviation between the controlled output and a target value is greater than the predetermined threshold value, and to set the control input to the hold control input when the control deviation is equal to or less than the predetermined threshold value,
• wherein the feedback controller is also configured to adjust the feedback control input to approach or coincide with the hold control input, when the control input is set to the hold control input.