Abstract: 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 (?) by adding an updating vector (d ?) to a reference vector (? base) of the model parameter. The updating vector (d ?) 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 (?) is calculated by adding the corrected updating vector (d ?) to the reference vector (? base).

Abstract: 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 (&thgr;) by adding an updating vector (d &thgr;) to a reference vector (&thgr; base) of the model parameter. The updating vector (d &thgr;) 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 (&thgr;) is calculated by adding the corrected updating vector (d &thgr;) to the reference vector (&thgr; base).

Abstract: An automatic disk changer is disclosed in which tray guides are provided on a large number of levels in a case at right and left portions thereof so that the center line of the guide on each of the levels at the right portion and that of the guide on the level at the left portion extend toward a tray transfer mechanism and meet each other in the form of a V. The tray transfer mechanism can be moved up and down between each of the guides and a disk player for playing a disk in a tray transferred by the tray transfer mechanism, be swung from a central portion to positions corresponding to the guides on each of the levels at the right and left portions, and be moved backward and forward, to and from each of the guides.