Underwater Robots - Gianluca Antonelli.pdf

232 9. Coordinated Control of Platoons of AUVs
apartially decentralized version of the kinematic control is proposed to properly
consider the limited bandwidth of the platoon.
9.2.1 Simulations
The kinematic-control-based algorithm has been tested in numerical simulation
case studies. The objective ofthe simulations is to show the performance
of the sole CLIK algorithm, while assuming abounded tracking error of the
vehicle controllers. The platoon is composed of 10 vehicles; the sampling time
of the CLIK is 0 . 5s and the total simulation duration is 100s.The primary
task is the platoon average position, while the secondary task is the variance.
In detail, the average is commanded to be constant along y and increases
linearly at avelocity of1m/s along x :
� �
t
σ a = m
0
while the desired variance is
� �
30
σ v = m
30
2 .
The CLIK’s gains have been set to:
Λ a =0. 1 I 2
Λ v =0. 05I 2 .
In case of presence of obstacles or excessive proximity among the vehicles,
the primary task is the obstacle avoidance, while mean and variance are,
respectively, second and third task. Asafe distance of 4mamong the vehicles
is required. InFigure 9.2 it can be observed that, in absence of obstacles, the
vehicles reconfigure themselves in order to fulfill mean and variance task.
The same initial condition with the same mean and variance tasks have
been used to run asecond simulation with the presence of an obstacle. One of
the vehiclesneeds to slowdownits velocity, avoid the vehiclesinits proximity,
avoid the obstacle and finally join the other vehicles tofulfill the meanvariance
task (Figure 9.3).
Figure 9.4 shows the same mission (same required mean and variance
starting from the same initial conditions) with the presence of3obstacles. It
can be recognized that the mission is safely executed.