06.02.2013 Views

Underwater Robots - Gianluca Antonelli.pdf

Underwater Robots - Gianluca Antonelli.pdf

Underwater Robots - Gianluca Antonelli.pdf

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

[m]<br />

[deg] [deg]<br />

0.1<br />

0.05<br />

0<br />

−0.05<br />

7.8 Output Feedback Control 173<br />

−0.1<br />

0 5 10<br />

time [s]<br />

15 20<br />

20<br />

10<br />

0<br />

−10<br />

−20<br />

θ<br />

0 5 10<br />

time [s]<br />

15 20<br />

40<br />

20<br />

0<br />

q 1<br />

q 3<br />

−20<br />

q 2<br />

φ<br />

ψ<br />

−40<br />

0 5 10<br />

time [s]<br />

15 20<br />

Fig. 7.12. Output feedback control. Desired trajectories used in the case studies.<br />

Top: vehicle position; Middle: vehicle orientation (RPY angles); Bottom: joint positions<br />

where ζ r = ζ d + Λ d e d .The vectors ˙ ζ and ˙ ζ r are computed via first-order<br />

difference. The above control lawisanalogoustothe operational space control<br />

law proposed in [266] and extended in [108] in the framework of quaternionbased<br />

attitude control. To obtain acontrol law ofcomputational complexity<br />

similar to that of (7.41), the algorithm (7.61) has been modified into the<br />

simpler form<br />

�<br />

†<br />

u = B M ( q ) ˙ ζ r + K v ( ζ r − ζ )+K p e d + g ( q , R I �<br />

B )<br />

The parameters in the control laws are set to<br />

Λ d =blockdiag { 0 . 005I 3 , 0 . 01I 3 , 0 . 01I 3 } ,<br />

Λ e =blockdiag { 5 I 3 , 10I 3 , 10, 10, 5 } ,<br />

z<br />

. (7.62)

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!