Non-Linear Design of an IGV-FAN Servo System for Surface Effect Ships

Abstract In this paper, the problem of designing a servo system for Surface Effect Ship applications, based upon a centrifugal fan complemented with an Inlet Guide Vane (IGV), is considered. An IGV-fan system, at constant fan speed, can be regarded as a single-input (the opening of the intake valve) single-output (the delivered air flow) dynamical system, affected by a measurable disturbance (the pressure at the output). The IGV-fan system is characterised by non-trivial non-linearities. For the servo design, a back-box direct method which makes use of I/O measurement only has been used. Such a method provides satisfactory performances when used for the design of the approximate inverse of the IGV-fan system.