An environment directed to e-learning is presented for teaching test generation and fault diagnosis in digital circuits. The environment consists of a set of Java applets for learning basics of test preliminary and of...
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Guidance through waypoinis 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 waypoinis 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 waypoinis. 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 lineof-sight guidance in the diving plane. Copyright 2004 IFAC.
In most applications, a mobile robot must be able to determine its position and orientation in the environment using only own sensors. The problem of pose tracking can be seen as a constituent part of the more general...
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In most applications, a mobile robot must be able to determine its position and orientation in the environment using only own sensors. The problem of pose tracking can be seen as a constituent part of the more general navigation problem. Our proposed approach is able to track the mobile robot pose without environment model. It is based on combining histograms and Hough transform (HHT). While histograms for position tracking (x and y histograms) are extracted directly from local occupancy grid maps, angle histogram is obtained indirectly via Hough transformation combined with a non-iterative algorithm for determination of end points and length of straight-line parts contained in obtained histograms. Histograms obtained at the actual mobile robot pose are compared to histograms saved at previous mobile robot poses to compute position displacement and orientation correction. Orientation estimation accuracy greatly influences the position estimation accuracy and is crucial for a reliable mobile robot pose tracking. Sensors used for local occupancy grid generation are sonars but other exteroceptive sensors like a laser range finder can also be used. Test results with mobile robot Pioneer 2DX simulator show the capacity of this method.
Guidance through waypoints is common for small autonomous marine vehicles. Guidance by the line of sight, the basic waypoint guidance algorithm, is very simple, computationally inexpensive, and flexible to sudden chan...
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Guidance through waypoints is common for small autonomous marine vehicles. Guidance by the line of sight, the basic waypoint guidance algorithm, is very simple, computationally inexpensive, and flexible to sudden changes in the desired path specification. On the other side, the basic algorithm achieves unoptimal vehicle trajectory, ignores possible side disturbances as sea currents, and can even lead to deadlock situations. Therefore it should be improved to use in the real world applications. This paper introduces several such improvements: missed waypoint detection to prevent deadlocks, novel reference heading correction method to give smoother vehicle path in turns at waypoints, and sea current compensation method to cancel its influence. This improvements address the mentioned flaws of the basic algorithm, as is demonstrated by the simulations, and yet keep it simpler than is the case for the most used waypoint-derived guidance methods.
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...
详细信息
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.
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