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Underwater Robots - Gianluca Antonelli.pdf

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vehicle position [m]<br />

0.1<br />

0.05<br />

0<br />

−0.05<br />

z<br />

x<br />

−0.1<br />

0 10 20 30<br />

time [s]<br />

y<br />

7.10 Conclusions 199<br />

Fig. 7.36. Virtual decomposition control +proper adaptiveaction. Vehicleposition<br />

vehicle orientation [deg]<br />

4<br />

2<br />

0<br />

−2<br />

φ<br />

−4<br />

0 10 20 30<br />

time [s]<br />

Fig. 7.37. Virtual decomposition control +proper adaptive action. Vehicle orientation<br />

forces that act on asubmerged body. Asshown in Chapter 3,neglecting the<br />

physical nature ofthese forces can cause the controller to feed the system<br />

with adisturbance rather than aproper control action.<br />

At the same time, an UVMS is acomplex system, neglecting the computational<br />

aspect can lead the designer todevelop acontroller for which the<br />

tuning and wet-test phase might beunpractical. Starting from the simulation<br />

phase it might beappropriate to test simplified version of the controllers.<br />

Among the control strategies analyzed the Virtual Decomposition approach,<br />

merged with the proper adaptation action, has several appealing<br />

characteristic: it is adaptive in the dynamic parameters; it is based on a<br />

Newton-Euler formulation that keep limited the computational burden; it is<br />

ψ<br />

θ

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