Underwater Robots - Gianluca Antonelli.pdf

62 3. Dynamic Control of 6-DOF AUVs
desired orientation [deg]
100
80
60
40
20
0
φ
θ
−20
0 100 200
time [s]
300 400
Fig. 3.3. Desired trajectory; the desired position is constant
Table 3.3. Initial conditions for all the controllers in their reduced version and
number of parameter to adapt/integrate
law number ofpar. ˆ θ ( t =0)
A 7 [0 0 0 0 0 0 1] T (initial value of the integral)
B – not simulated
C 10 [ − 9 0 50 0 0 0 0 0 0 0] T
D 10 [ − 9 0 50 0 0 0 0 0 0 0] T
E 9 [0 50 0 0 0 9 0 0 0] T
F 9 [0 50 0 0 0 9 0 0 0] T
Ocean current The simulations have been run considering the following
constant current
ν I c =[0 0. 3 0 0 0 0] T m/s ,
Gains selection All the simulated controllers are non-linear. Moreover, significant
differences arise among them, this is, in fact, the object of this discussion.
For these reasons it is very difficult toperform afair numerical
comparison and the selection of the gains is very delicate. The gains have
been tuned so as to give tothe controller similar control effort interms of
force/moment magnitude and eventual presence ofchattering. Infew cases,
since the controller feeds back the same variable, ithas been possible to chose
the same control gain, itisthe case, e.g., of the controllers C and E .Inother
cases, such as, e.g., the controller F ,the use of the transpose of the Jacobian
ψ