Underwater Robots - Gianluca Antonelli.pdf

102 5. Experiments Dynamic Control of a6-DOF AUV
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Fig. 5.7. Experiments of fault tolerant control on ODIN. Left: vehicle movement
along xy without thrusters’ faults. Right: vehicle movement along xy with thrusters’
faults. A, first fault at t =260 satone horizontal thruster. B, second fault
at t = 300 satone vertical thruster
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Fig. 5.8. Experiments of fault tolerant control on ODIN. Left: vehicle movement
along z without thrusters’ faults. Right: vehicle movement along z with thrusters’
faults. A, first fault at t =260 satone horizontal thruster. B, second fault
at t = 300 satone vertical thruster
there isasignificant transient inthe yaw angle that is quick recovered. Comments
similar to that done for the linear error in the horizontal plane could
be done.
In Figure 5.10 the voltages of the vertical and horizontal thrusters are reported.
We can see that when the thrusters are off, the desired force/moment
on the vehicle are redistributed on the working thrusters. From these plots we
can also appreciate the different noise onthe control caused bythe different
sensors; due tothe null roll and pitch angles, in fact, the vertical thrusters
work mainly totrack the vertical direction using the depth sensor while the
horizontal are mainly use to move the vehicle on the plane.
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