A control system for a plant is disclosed. In this control system, a model parameter vector of a controlled object model which is obtained by modeling said plant, is calculated. A sliding mode controller is included in the control system. The sliding mode controller controls the plant using the identified model parameter vector. A damping input is calculated according to a speed of change in an output of the plant, and an element of the model parameter vector. A control input form the sliding mode controller to the plant includes the calculated damping input.