Plant control device and control method using modulation algorithm

A controller for a variable lift mechanism of an internal-combustion engine, the controller using a modulation algorithm and comprising:

• means for providing a preliminary control input to be used for controlling a maximum lift amount of the variable lift mechanism to a desired lift amount;
• means for dividing the preliminary control input into a plurality of components;
• means for modulating at least one of the plurality of components;
• and
• means for adding the modulated component to the other components to generate a control input.

A controller for a variable phase mechanism of an internal-combustion engine, the controller using a modulation algorithm and comprising:

• means for providing a preliminary control input to be used for controlling a cam phase of the variable phase mechanism to a desired phase;
• means for dividing the preliminary control input into a plurality of components;
• means for modulating at least one of the plurality of components;
• and
• means for adding the modulated component to the other components to generate a control input.

An air/fuel ratio controller of an internal-combustion engine, the controller using a modulation algorithm and comprising:

• means for providing a preliminary control input to be used for controlling an output of an exhaust gas sensor on a desired value;
• means for dividing the preliminary control input into a plurality of components;
• means for modulating at least one of the plurality of components;
• and
• means for adding the modulated component to the other components to generate a control input.

A controller for an automatic transmission mechanism of an internal-combustion engine, the controller using a modulation algorithm and comprising:

• means for providing a preliminary control input to be used for controlling an output position of the automatic transmission mechanism on a desired position;
• means for dividing the preliminary control input into a plurality of components;
• means for modulating at least one of the plurality of components;
• and
• means for adding the modulated component to the other components to generate a control input.

A method for controlling a plant, comprising:

• providing a preliminary control input to be used for controlling an output of the plant to a desired value;
• dividing the preliminary control input into a plurality of components;
• modulating at least one of the plurality of components;
• and
• adding the modulated component to the other components to generate a control input.