3 research outputs found
Ant colony optimized planning for unmanned surface marine vehicles
This paper presents some results achieved from a preliminary study on the use
of the Ant Colony Algorithm to plan feasible optimal or suboptimal trajectories
for an autonomous ship manoeuvring. The scenario, for this preliminary work,
comprises only open sea manoeuvres. The goal involves obtaining the least
time consuming ship trajectory between to points, departing from the start
point with arbitrary initial speed and attitude values and arriving to the end
point with predefined speed and attitude values.
The specific dynamic of the ship imposes typical restrictions to its manoeuvrability.
In the present case, the non-holonomicity, the rate speed/turn radius,
and the imposed forward-only propulsion of the ship make up the main restrictions
to the ship movement. For long distances, the problem could be tackled
as a classical navigation problem, in which, for the most part of the ship
trajectory, techniques such inertial navigation should be enough. The problem
arises at short distances when it becomes a manoeuvring problem. In this case
to obtain a optimal, --in some cases just a feasible--, trajectory could be a difficult
problem.Peer Reviewe
Ant colony optimized planning for unmanned surface marine vehicles
This paper presents some results achieved from a preliminary study on the use
of the Ant Colony Algorithm to plan feasible optimal or suboptimal trajectories
for an autonomous ship manoeuvring. The scenario, for this preliminary work,
comprises only open sea manoeuvres. The goal involves obtaining the least
time consuming ship trajectory between to points, departing from the start
point with arbitrary initial speed and attitude values and arriving to the end
point with predefined speed and attitude values.
The specific dynamic of the ship imposes typical restrictions to its manoeuvrability.
In the present case, the non-holonomicity, the rate speed/turn radius,
and the imposed forward-only propulsion of the ship make up the main restrictions
to the ship movement. For long distances, the problem could be tackled
as a classical navigation problem, in which, for the most part of the ship
trajectory, techniques such inertial navigation should be enough. The problem
arises at short distances when it becomes a manoeuvring problem. In this case
to obtain a optimal, --in some cases just a feasible--, trajectory could be a difficult
problem
Signal Conditioning for the Kalman Filter: Application to Satellite Attitude Estimation with Magnetometer and Sun Sensors
Most satellites use an on-board attitude estimation system, based on available sensors. In the case of low-cost satellites, which are of increasing interest, it is usual to use magnetometers and Sun sensors. A Kalman filter is commonly recommended for the estimation, to simultaneously exploit the information from sensors and from a mathematical model of the satellite motion. It would be also convenient to adhere to a quaternion representation. This article focuses on some problems linked to this context. The state of the system should be represented in observable form. Singularities due to alignment of measured vectors cause estimation problems. Accommodation of the Kalman filter originates convergence difficulties. The article includes a new proposal that solves these problems, not needing changes in the Kalman filter algorithm. In addition, the article includes assessment of different errors, initialization values for the Kalman filter; and considers the influence of the magnetic dipole moment perturbation, showing how to handle it as part of the Kalman filter framework