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Adaptative high-gain extended Kalman filter and applications

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tel-00559107, version 1 - 24 Jan 2011<br />

− the selection of the compilation options,<br />

4.3 real-time Implementation<br />

− the setting of the real-time parameters (sample time of the real-time executable,...),<br />

− the display of a successful compilation notification.<br />

The program that was compiled above is called Phd DEMO. This real-time executable is<br />

started from the system console with one of the two following comm<strong>and</strong> lines:<br />

− ./Phd DEMO -f xx<br />

− ./Phd DEMO<br />

In the first case, the -f option specifies that a duration of execution is provided. The xx<br />

symbols have to be replaced by the desired length of time, in seconds. In the second case, no<br />

duration is given <strong>and</strong> the program runs until it is stopped by the user. In RTAI-Lab, there<br />

is only one way to properly stop a real-time executable while it is running, i.e., to use the<br />

Xrtailab application.<br />

As for Scilab, Xrtailab can be launched from a system console. The use of Xrtailab is<br />

illustrated in Figure 4.23. The two first images give an account of the connection procedure.<br />

The last image demonstrates a few possibilities of Xrtailab such as the display of signals<br />

entering a Scope block or the ability to change blocks parameters on the fly.<br />

A more detailed explanation on how the whole RTAI-lab suite works may be found in<br />

[34].<br />

4.3.2 Hardware<br />

The testbed is composed of<br />

− a DC motor from Lucas Nuelle (ref. SE2665-5C) that can be connected in series. This<br />

machine is coupled<br />

– on one end with a tachometer 17 (ref.2662-5U),<br />

– on the other end with a propeller 18 (47.0 x 30.5 cm, together with a 5 ◦ pitch).<br />

The propeller is attached to a 52mm center hub. Those parts were manufactured<br />

by Aero-naut (ref.7234/97),<br />

− a programmable DC source from Delta Electronika (SM-300-10D),<br />

− an I/O card from National Instruments (6024E-DAQ) that allows for communications<br />

between the physical system <strong>and</strong> the control system.<br />

A communication diagram showing the relationship between the different elements of the<br />

testbed is provided in Figure 4.24. The figure shows:<br />

17<br />

The tachometer is only used in order to compare the estimated speed to the real one, <strong>and</strong> to calibrate the<br />

mathematical model (see Subsection 4.3.3) .<br />

18<br />

The brake we had at our disposal was not working properly. We therefore decided to pursue the experiments<br />

without it. As it can be seen from the second equation of system (4.1), if the resistive torque is not<br />

sufficient, there are good chances for the machine to run wild. The role of the propeller is to provide the motor<br />

with a sufficiently <strong>high</strong> <strong>and</strong> stable resistive torque. We chose our propeller on behalf of the study [44].<br />

79

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