Guidance through waypoints is common for small autonomous marine vehicles. Guidance by the line of sight, which turns the vehicle directly towards the next waypoint without any reference path calculation, is computati...
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Guidance through waypoints is common for small autonomous marine vehicles. Guidance by the line of sight, which turns the vehicle directly towards the next waypoint without any reference path calculation, is computationally the simplest form of waypoint guidance. However, the basic algorithm gives rather poor guidance due to the missed waypoint problem, lack of sea current compensation and abrupt transitions between the consecutive waypoints. Significant path deviations and even deadlocks are possible due to these problems. Therefore, more complex algorithms are usually used in real world applications. The research reported in this paper aims to demonstrate that significant improvements of the basic line-of-sight guidance algorithm can be achieved by several intuitive, simple corrections and additions. The simplicity of the basic line-of-sight guidance algorithm is not compromised. In particular, missed waypoint detection is performed by monitoring the distance between the vehicle and the waypoint. Introduced reference heading corrections are based upon the location of the next waypoint after the one the vehicle is currently approaching, and upon the sea current direction and intensity. The results of these corrections are shown in several simulation examples. In addition, the paper includes a short discussion about the line-of-sight guidance in the diving plane.
This panel paper presents the views of six researchers and practitioners of simulation modeling. Collectively we attempt to address a range of key future challenges to modeling methodology. It is hoped that the views ...
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ISBN:
(纸本)9780780387867
This panel paper presents the views of six researchers and practitioners of simulation modeling. Collectively we attempt to address a range of key future challenges to modeling methodology. It is hoped that the views of this paper, and the presentations made by the panelists at the 2004 Winter Simulation Conference will raise awareness and stimulate further discussion on the future of modeling methodology in areas such as modeling problems in business applications, human factors and geographically dispersed networks; rapid model development and maintenance; legacy modeling approaches; markup languages; virtual interactive process design and simulation; standards; and Grid computing.
作者:
Brščić, DraženUniversity of Zagreb
Faculty of Electrical Engineering and Computing Department of Control and Computer Engineering in Automation Unska 3 ZagrebHR-10000 Croatia
This paper presents the current work on the development of a tool for remote control of mobile robots. The tool consists of a local controller on the robot side and a user interface for simulation and remote control t...
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This paper presents a specific use of a computer in electrical machines courses. Computer simulations over Internet have proven themselves useful because of their flexibility and availability. Such simulation of synch...
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This paper is concerned with the application of a heuristic approach in the design of a fault-tolerant control system for ship steering. It proposes an advanced reconfigurable control system (RCS) for ship course chan...
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This paper presents the current work on the development of a tool for remote control of mobile robots. The tool consists of a local controller on the robot side and a user interface for simulation and remote control t...
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This paper presents the current work on the development of a tool for remote control of mobile robots. The tool consists of a local controller on the robot side and a user interface for simulation and remote control that connects with the robot through the network. The user interface is implemented as an HTML page with a Java applet for remote control and communication and a virtual environment written in VRML for visualization. This way users have the ability to connect to a dedicated WWW server and download the user interface. This paper describes the concept of the tool design and the developed user interface.
Traditional approaches to controller designs that guarantee fast compensation of load torque and reference variations result in design iterations and most of the time in poorer response for load torque variations. In ...
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Traditional approaches to controller designs that guarantee fast compensation of load torque and reference variations result in design iterations and most of the time in poorer response for load torque variations. In this paper a reference model for desired drive behavior generation and optimization methods has been applied to achieve controller integral time constant lower than the maximum time constant of the PM brushless DC motor drive. Presented simulation results show that using reference model for desired drive behavior generation, it is possible to determine optimal controller parameters for faster (10 time) and better (2 time) load torque compensation than in the case of traditional design of speed controller parameters. Response due to reference input with constrained overshoot has been achieved using a filter in the servosystem input. Thereby, the proposed method demonstrates the design of a speed controller that is optimal for both load torque and reference variations and its verification with simulation are accomplished for a permanent magnet brushless dc motor drive.
In this paper a non-linear fuzzy autopilot for ship track-keeping is presented. The proposed autopilot has four inputs (actual and desired heading, rate of change of heading and offset from the desired path) and one o...
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In this paper a non-linear fuzzy autopilot for ship track-keeping is presented. The proposed autopilot has four inputs (actual and desired heading, rate of change of heading and offset from the desired path) and one output (command rudder angle). The track-keeping problem is decomposed into two subtasks: (i) followthe desired heading, and (ii) bring the ship onto the desired path and keep tracking. Internally, the autopilot consists of two autopilots that fulfil these tasks simultaneously. The proposed control scheme has been verified using a non-linear model of a Mariner-class vessel and steering mechanism under the influence of wave and current disturbances. Results presented show how such a control strategy enables improved tracking performance.
Distributed systems such as clusters of PCs are low-cost alternatives for running parallel rendering systems, but they have high communication overhead, and limited memory capacity on each processing node. We focus on...
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Distributed systems such as clusters of PCs are low-cost alternatives for running parallel rendering systems, but they have high communication overhead, and limited memory capacity on each processing node. We focus on the strategy for distributing the parallel rendering work among the PCs. A good distribution strategy provides better load balance, and avoids the need for replicating data on the relatively small memory of each PC. Our goal is to study different distribution strategies on the scope of the Parallel ZSweep algorithm, introducing in PZSweep another work distribution strategy: work stealing. This strategy allows a decentralized control of the work to be done, and provides a dynamic load redistribution. We propose two different algorithms to select the processor that will be "stolen" and show that the simplest one, nearest neighbor, was the most efficient. We also showed that the load redistribution schemes strongly depended on the initial load distribution, with an interleaved assignment, our systems could outperform the original parallel ZSweep algorithm. We conclude that for running large datasets on a cluster of PCs, parallel ZSweep requires dynamic load distribution strategy.
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