Time optimal control of time varying third order plants

Abstract

It has been shown that time invariant third order plants can be time optimally controlled by a hybrid computer. The computer generates a time optimal switching surface, which it then uses to control the plant. [1] This paper presents an extension of this approach to slow time varying plants, by automatically updating the switching surface. The effects that parameter changes have on the response of the plant and on the switching surface are investigated. It is shown that by rescaling the switching surface, the effects of parameter changes on the plant's response could be minimised. A method is then presented for the time optimal control of time varying plants. The method consists of on-line identification of the time varying parameters and the continuous updating of the switching surface to maintain time optimal control.