Identification and dual adaptive control of a turbojet engine

Abstract

The objective of this paper is to utilize the design methods of modern control theory to realize a ‘dual-adaptive’ feedback control unit for a highly non-linear air breathing turbojet engine. Using a very detailed and accurate simulation of the nonlinear engine as the data source, linear operating point models of unknown dimension are identified. Feedback control laws are designed at each operating point for a pre-specified set of sampling rates using sampled-data output regulator theory. The control system sampling rate is determined by an adaptive sampling algorithm in correspondence with turbojet engine performance. The result is a ‘dual-adoptive’ control law that is functionally dependent upon the sampling rate selected and environmental operating conditions. Simulation transients demonstrate the utility of the dual-adoptive design to improve on-board computer utilization while maintaining acceptable levels of engine performance.