Ship Track and Speed Model in Case of Steering Gear Breakdown with Rudder Remaining Fix at non Zero Angle

Ship navigation is determined by the ship’s position on a certain part of the fairway from the place of departure to the place of arrival. During the voyage, in a given period of time ship changes the course and the speed. Navigation itself can be viewed from the aspect when during the voyage all onboard systems are functioning properly and the person managing the ship practices good seamanship, and from the aspect when an extraordinary event occurs, which affects the possibility of maintaining the desired course and/or speed. This paper analyzes the movement of the ship in case of an extraordinary event with the assumption that the malfunction occurred in the steering system. Depending on the navigation area and the sea traffi c, such an event generates two basic maritime navigation risks, the risk of ship grounding and the risk of collision. This paper explores ship movement that, depending on the scenario, may result in ship grounding. For the purposes of conducting research on ship movement due to the assumed extraordinary event onboard, various scenarios were defi ned. To create a track model, an Euler spiral/clothoid was chosen. By modifying the parametric clothoid equation, a curve was obtained which very well approximated the curve of a turning ship. Furthermore, developed was the speed change model that can show the speed change at any point of the curve of a turning ship when the rudder defl ection was constant, and the engine was stopped. The designed models were tested in 60 scenarios in accordance to which the research on the navigation simulator was carried out. Ship track model can be used in the fi eld of research for simulation model development, the result of which will enable determining the extent of grounding damage, and after determining the extent of grounding consequences, it will enable the defi ning of acceptable risk as well

Path planning for unmanned aerial vehicles using visibility line-based methods

This thesis concerns the development of path planning algorithms for unmanned aerial vehicles (UAVs) to avoid obstacles in two- (2D) and three-dimensional (3D) urban environments based on the visibility graph (VG) method. As VG uses all nodes (vertices) in the environments, it is computationally expensive. The proposed 2D path planning algorithms, on the contrary, select a relatively smaller number of vertices using the so-called base line (BL), thus they are computationally efficient. The computational efficiency of the proposed algorithms is further improved by limiting the BL’s length, which results in an even smaller number of vertices. Simulation results have proven that the proposed 2D path planning algorithms are much faster in comparison with the VG and hence are suitable for real time path planning applications. While vertices can be explicitly defined in 2D environments using VG, it is difficult to determine them in 3D as they are infinite in number at each obstacle’s border edge. This issue is tackled by using the so-called plane rotation approach in the proposed 3D path planning algorithms where the vertices are the intersection points between a plane rotated by certain angles and obstacles edges. In order to ensure that the 3D path planning algorithms are computationally efficient, the proposed 2D path planning algorithms are applied into them. In addition, a software package using Matlab for 2D and 3D path planning has also been developed. The package is designed to be easy to use as well as user-friendly with step-by-step instructions

Earplug

Earplug have been created since a long time ago, the earliest patent earplug was made in 1884. Human tend to use finger to cover their ears to blocking the noise absorb by the ear. It was surprisingly effective but human unable to sustain for a long period of time and while using finger to decrease the volume, human unable to do other work in such condition

Estratégias para planejamento de movimento de veículos subaquáticos baseado em G2CBS

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2016.Os riscos e custos envolvidos nas operações submarinas tornam atrativas a pesquisa e o desenvolvimento de veículos subaquáticos. Uma área de pesquisa muito forte em relação aos veículos subaquáticos visa a aumentar a capacidade desses veículos de analisar sua missão, planejar o seu movimento e adaptar sua operação de acordo com as condições do ambiente. Planejamento de movimento refere-se aos algoritmos utilizados para converter uma especificação de tarefa de alto nível em descrições de baixo nível de como o veículo deve se mover. O planejamento de movimento para veículos subaquáticos geralmente ignora as restrições cinemáticas e dinâmicas dos veículos, o que resulta em erros de posicionamento durante o seguimento do caminho. Uma aproximação dessas restrições pode ser incluída no processo de planejamento de movimento através do uso de espirais cúbicas de Bézier com continuidade G² (G2CBS). As G2CBS consistem na concatenação de duas curvas de Bézier, cujos pontos de controle são calculados de forma que a curva resultante possua curvatura contínua e limitada a um valor ?_max, o qual representa a aproximação das restrições cinemáticas e dinâmicas do veículo. Neste trabalho são apresentadas as G2CBS em detalhes, é feito um estudo sobre a cinemática e dinâmica de veículos subaquáticos, e são propostas novas estratégias para planejamento de movimento e desvio de obstáculos, e associada à especificação da direção do caminho, um método de otimização e proposto e comparado.Abstract : The hazards and costs associated to subaquatic operations make the research and development of underwater vehicles attractive. A very strong research line related to underwater vehicles aims to increase these vehicles capacity of analyzing their missions, planning their movement and adapting their operation according to environmental conditions. Movement planning for underwater vehicles usually disregard their kinematic and dynamic constraints, which results in positioning errors during the following of the planned path. The kinematic and dynamic constraints can be readily included in the movement planning process through the use of G²-continuous cubic Bézier spirals (G2CBS). The G2CBS consist in the concatenation of two Bézier curves, whose control points are calculated in such a way that the resulting curve has a continuous curvature limited to a certain value ?_max, which in turn represents na approximation of the vehicle?s kinematic and dynamic constraints. In this work the G2CBS are presented in details, the kinematics and dynamics of underwater vehicles are reviewd, and new strategies for movement planning and obstacle avoidance are proposed

Generación de Trayectorias de Curvatura Continua para el Seguimiento de Líneas basado en Visión Artificial

Desarrollo matemático y análisis de nuevas técnicas para la generación de trayectorias de curvatura continua aplicado al problema del seguimiento de línea con curvatura y brusquedad acotadas.Girbés Juan, V. (2010). Generación de Trayectorias de Curvatura Continua para el Seguimiento de Líneas basado en Visión Artificial. http://hdl.handle.net/10251/12881Archivo delegad

Geometrie und Topologie von Trajektorienoptimierung für vollautomatisches Fahren

Zur Erschließung allgemeiner Prinzipien für das Themenfeld der Bewegungsplanung für vollautomatisches Fahren wird eine intuitive Problemformulierung als Euler-Lagrange-Modell aufgestellt und zur globalen Optimierung in ein korrespondierendes Hidden-Markov-Modell umgewandelt. Geometrische und topologische Betrachtungen führen zu einer probabilistischen Umgebungsmodellierung in Kombination mit dem C²-Modell und resultieren in universellen Schlussfolgerungen über die Struktur von Verkehrsgeschehen