This example shows the simulation of an attitude-rate control system for an aircraft using a

QFIRE CTR-101

as controller.

Introduction

The aircraft is represented by the transfer function below

The

QFIRE CTR-101

acts by a hydraulic servo controlling the system. A rate gyro is in the feedback loop.

Simulation

The control law is represented by equation 1 and corresponds to three transfer functions in series.

Aiming to use the Transfer Function block, it is necessary to simplify the equation. This way, it is possible to fill the Transfer Function Properties correctly as represented in Figure 2.

Due to order of the transfer functions of this example and the data type of

QFIRE CTR-101

, i.e. 32-bit fixed-point with 15 bits used for the integer part and 1 for signal, it may suffer drastic influence of quantization error. Aiming to avoid these problems, the reference signal was set to 100.

In this example, the Analog Input receives the response signal and the Analog Output sends the control signal as can be seen in Figure 1.

In Figure 1 and Figure 3, it is possible to see the Scaling Subsystem. These subsystems adapt the signal to the Analog Input and Output ranges working as an amplifier and an attenuator.

As a result, the response signal of the plant is represented in Figure 4.

Bibliographic References

[1] Katsuhiko Ogata,

Modern Control Engineering

, Fourth Edition, Delhi: Pearson, 2003.