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.

216 8. Interaction Control of UVMSs<br />

[N]<br />

[m]<br />

350<br />

300<br />

250<br />

200<br />

150<br />

100<br />

50<br />

0<br />

0.2<br />

0.1<br />

0<br />

−0.1<br />

0 5 10 15<br />

time [s]<br />

˜y E<br />

˜x E<br />

f e,z<br />

f e,x<br />

−0.2<br />

0 5 10 15<br />

time [s]<br />

Fig. 8.8. External force control. Force along z and x (top) and end-effector error<br />

components along the motion directions (bottom) exploiting the redundancy and<br />

with unexpected impact along x<br />

Explicit force control, scheme 1. Asketch ofthe implemented scheme<br />

is provided in Figure 8.9. Inour case, the inverse kinematics is solved via<br />

anumerical algorithm based onvelocity mapping to allow the handling of<br />

system redundancy efficiently (see previous Section and Section 6.5). It is<br />

possible to decompose the input torque as the sum of the torque output<br />

from the motion control and the torque output from the force control: τ =<br />

τ M + τ F .The force control action τ F is computed as:<br />

τ F = J T posu F<br />

= J T pos<br />

�<br />

− f e + k f,p ˜ f e − k f,v ˙ f e + k f,i<br />

� t<br />

0<br />

�<br />

˜f e ( σ ) dσ , (8.17)

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

Saved successfully!

Ooh no, something went wrong!