Abstract
A proportional solenoid valve is applied to an automatic transmission to control shift operation. Its control system must be designed as a robust control system considering modeling error caused by a change in characteristics of the valve. In this study, a brake mechanism of an automatic transmission is considered as a plant. Two degree of freedom control of its rotating speed is studied in which modeling error due to a change in characteristics of a proportional solenoid valve is took into account. A feedback controller is designed based on μ synthesis in which a change in characteristics of the valve and variations of a frictional coefficient are considered as uncertainty of a nominal model. Introducing a feed-forward controller, a two degree of freedom control system is constructed. The control system is examined through experiment using a commercial proportional solenoid valve. Shift operation is precisely controlled by the control system under those fluctuating factors.
