Underwater Robots - Gianluca Antonelli.pdf

7. Dynamic Control of UVMSs
7.1 Introduction
In Chap. 2the equations ofmotion of Underwater Vehicle-Manipulator Systems
(UVMSs) have been presented. Their expression in matrix form (2.71),
is formally close to the equations of motion ofground fixed manipulators for
which awide control literature exists. This has suggested asuitable translation/implementation
of existing control algorithms. However, some differences,
crucial from the control aspect, need to be underlined. UVMSs are
complex systems characterized by several strong constraints:
• Uncertainty in the model knowledge, mainly due tothe poor knowledge of
the hydrodynamic effects;
• Complexity ofthe mathematical model;
• Kinematic redundancy of the system;
• Difficulty tocontrol the vehicle in hovering, mainly due to the poor thrusters
performance;
• Dynamic coupling between vehicle and manipulator;
• Low bandwidth of the sensor’s readings.
In [197, 198] adiscrete adaptivecontrol strategyfor coordinated control of
UVMSs is presented. Numerical simulations, on aplanar task, show that the
use of acentralized controller, better than two separate controllers, one for the
vehicle and one for the manipulator, guarantees performance improvement.
Reference [124] shows an adaptive macro-micro control for UVMSs. Inverse
kinematics is obtained by inversion of the Jacobian matrix; hence, a
manipulator with 6degrees of freedom is required. Astability analysis in
Lyapunov sense is provided.
An adaptivecontrol lawfor an underwatermanipulatorisproposed in [59].
Aself-tuning PID controller is developed and tested in simulation on a2link
manipulator with fixed base. In [190] too, an underwater manipulator
with fixed base is considered. Adescription of atelerobotic control system is
provided in [181].
The use of multiple manipulators to be used asstabilizing paddles is investigated
by means of simulations in [168]. Those concern avehicle carrying
a6-DOF manipulator plus apair of 2-link manipulators counteracting the
interaction force between vehicle and manipulator aspaddles.
G. Antonelli: Underwater Robots, 2nd Edition, STAR 2, pp. 141–200, 2006.
© Springer-Verlag Berlin Heidelberg 2006