PLANT CONTROL APPARATUS

A control system for a plant is provided. This control system can control the plant more stably, when the model parameters of the controlled object model which are obtained by modeling the plant, which is a controlled object, are identified and the sliding mode control is performed using the identified model parameters. The model parameter identifier (22) calculates a model parameter vector (&thetas;) by adding an updating vector (d &thetas;) to a reference vector ( &thetas; base) of the model parameter. The updating vector (d&thetas;) is corrected by multiplying a past value of at least one element of the updating vector by a predetermined value which is greater than "0" and less than "1". The model parameter vector (&thetas;) is calculated by adding the corrected updating vector (d &thetas;) to the reference vector (&thetas; base).