Underwater Robots - Gianluca Antonelli.pdf

192 7. Dynamic Control of UVMSs
In Figure 7.25 the time history of the vehicle position is reported. Itcan
be noted that the main tracking error is observed along z .This is due to
the fact that the vehicle is not neutrally buoyant and atthe beginning the
estimation of the restoring forces has to wait for the adaptation ofthe control
law. This can be observed also from Figure 7.26, where the time history of
the vehicle linear forces is reported. Since, the manipulator isnot neutrally
buoyant, alarge force is experienced along the z -axis at rest.
vehicle position [m]
0.1
0.05
0
−0.05
y
z
x
−0.1
0 10 20 30
time [s]
Fig. 7.25. Virtual decomposition control. Time history of the vehicle position
vehicle forces [N]
0
−500
−1000
x y
−1500
0 10 20 30
time [s]
Fig. 7.26. Virtual decomposition control. Time history of the vehicle linear forces
In Figure 7.27 the time history of the vehicle attitude in terms of Euler
anglesisshown. It canbenotedthatthe main tracking error is observed along
z