Control structure design methods applied to a jet engine

Future jet engines will be more complex with more variables to control to meet increasing demands on functionality. The interaction between the engine and aircraft systems will also increase, with mission-specific control and with control of thrust direction. To utilise the potential of these engines, it is also necessary to use more advanced control concepts than are conventionally used today. Multivariable controllers are most often at the core of these advanced control concepts. Important parts of a multivariable control design are to select suitable inputs and outputs and how to configure the control laws. This is referred to as control structure design (CSD). Some methods to accomplish this have been evaluated at Volvo Aero. A model of a typical jet engine has been used as application in this evaluation. The general impression from this work is that the tested methods are very usable to select between a large number of possible structures. However, it is essential to combine the use of the methods with application knowledge and understanding of the control objectives