This report documents the progress, methods and engineering in building and testing the
framework for CyberShip Enterprise 1. The main focus have been to modularize, standardize and improve the infrastructure and the operative system with respect to performance.
With a secondary objective to create a user-manual to operate it.
The work is done for a surface vessel in 3 degrees of freedom, surge, sway and yaw, and
in calm waters and slow speed.
The reliability when conducting laboratory experiments with CyberShip Enterprise 1 have
greatly improved. This was achieved through repositioning and replacing the antenna
for wireless communication, and a restructuring of how signals were handled between
servers and softwares. The original setup with single frequency was replaced with a multifrequency producer-consumer structure.
The futherst away a vessel is visible for Qualinsys is around 17 meters from the cameras.
The shortest distance is roughly 4 meters infront of the cameras. This result in a lengthwise
workspace for a vessel to be in the range of 13 meters. This length length can be increased
to 27 meters, If the carriage start from the beach end, and moves toward the wavemaker
during the experiment. It is not possible to increase it futher due to the length of the
basin, the wavemaker, beach, in/outlet and carriage is occupying.
In the system identication, an addtitonal hydrodynamic damping coecent for slow speed
have been determined for the hull (Nv
= 0:18140). In addtion higher order coecent have
also been estimated from the towing measurements. A pseudo library for lookup table
thruster mapping have been created. The bow thruster have been mapped for power limit
input = f0.15, 0.3, 0.4, 0.5g, and the voith schneider propellers for speed input = f0.3,
0.4g. Measurments for voith schneider propellers for speed = 0.2 have also been conducted,
but no lookup table have been created for it.
The starboard voith schneider propeller rotates slow than the port voith schneider propeller. It is also noted that the servos are signicantly coupled and the force output drops
at the periphery value , 1 . Of the servos, servo 4 have the strongest coupling in surge-sway.
Two advance control design were implemeted, tuned and tested, a LgV backstepping and
a Nonlinear PID designed controller. In the ideal simulated word both of them were equal
in terms of maneuvering. Only ellipse path was used in the laboratory. This had to do
with space constraints, and a wish to have long run time on the experiments.
Originally only the LgV backstepping was tested in the laboratory. It converged and performed well. The only downside was it would constantly overshoot the heading, resulting
in a constant oscillation, while moving alone the path. The reason was due to the noisy
In the laboratory, their performance depended heavily on how they were implemented. If
both of them were fully implemented, LgV backstepping proved to handle the uncertainties
better. Although it would overshoot when exiting the sharper part of the ellipse path.
While the fully implemented Nonlinear PID would struggle to converge to the path and
behave erratic.The velocity dependent term distorted Nonlinear PID 's results the most.
The Nonlinear PID is the superior one if only the rst term iss active. It would converge
naturally to the desired position. Once on, it would stay there indenitely despite of the
broken servo arm.
With all the improvement in the reliability, one important problem still remains; the loss
of visibility. There are incidents when Qualinsys displays it sees all markes, but it is
unable to calculate the vessels position and orientation. The cause of this needs to be
further investigated. Spare part servo arms should be purchased, and padding for the hull
to dampen the impact to the basin walls. Several crack have been observed on the hull.
Simulation Interface Toolkit have been discontinued, modifying it for Modular Interface
Toolkit can be an option. The labeling and choice of variable name can be improved upon.
Institutt for marin teknikk , 2014. , 88 p.