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Adaptative high-gain extended Kalman filter and applications

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

!<br />

!" #<br />

Figure 4.24: Connections Diagram.<br />

4.3 real-time Implementation<br />

Figure 4.25: A view on the testbed (<strong>and</strong>, on the left, the friction tool).<br />

observability normal form is then<br />

⎛<br />

˙x1<br />

⎝ ˙x2<br />

˙x3<br />

⎞<br />

⎠ =<br />

⎛<br />

⎝ 0 − Laf<br />

0<br />

1<br />

L<br />

0<br />

0<br />

− 1<br />

0 0<br />

⎛<br />

J<br />

0<br />

⎞ ⎛<br />

⎠ ⎝<br />

⎜<br />

+ ⎜<br />

⎝<br />

�<br />

1<br />

L u(t) x2<br />

x1<br />

x2<br />

x3<br />

⎞<br />

⎠<br />

1<br />

L<br />

(u(t) − Rx1)<br />

�<br />

Laf2x31 − Bx2 − p x2.08<br />

2<br />

x1.08 �<br />

�<br />

1<br />

u(t) x3<br />

⎟<br />

�<br />

⎠<br />

x2x3 − Laf1 − Rx3<br />

x1 x1 .<br />

x1 − Rx2 − Laf1 x2 �<br />

2 + x1<br />

1<br />

J<br />

1<br />

L<br />

This model needs to be calibrated, i.e., we need to find appropriate values for the parameters<br />

R, L, B, J, Laf1 ,Laf2 <strong>and</strong> p. We find the values following a st<strong>and</strong>ard approach. First,<br />

we applied a linear method in order to identify some of the parameters. Second, we used<br />

a nonlinear optimization technique to obtain more accurate values for the complete set of<br />

parameters.<br />

1. From data samples (voltage, current <strong>and</strong> speed) an initial estimation is obtained via<br />

the least mean squares technique.<br />

Let us consider the initial model (not in normal form) at steady state. Suppose that<br />

L = J = 1 <strong>and</strong> that the load torque (Tl) is null. With the parameters B, Laf ,p as<br />

82<br />

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