Simulink Control Design™ - MathWorks

Fixed-Structure Autopilot for a Passenger Jet

This example shows how to use slTuner and systune to tune the standard configuration

of a longitudinal autopilot. We thank Professor D. Alazard from Institut Superieur de

l'Aeronautique et de l'Espace for providing the aircraft model and Professor Pierre

Apkarian from ONERA for developing the example.

Aircraft Model and Autopilot Configuration

The longitudinal autopilot for a supersonic passenger jet flying at Mach 0.7 and 5000 ft is

depicted in Figure 1. The autopilot main purpose is to follow vertical acceleration

commands issued by the pilot. The feedback structure consists of an inner loop

controlling the pitch rate and an outer loop controlling the vertical acceleration. The

autopilot also includes a feedforward component and a reference model that

specifies the desired response to a step command. Finally, the second-order roll-off

filter

is used to attenuate noise and limit the control bandwidth as a safeguard against

unmodeled dynamics. The tunable components are highlighted in orange.

13 Control System Tuning Examples