Cooperative micro-robotic scent tracking vehicles are designed to collectively "sniff out" locations of high scent concentrations in unknown, geometrically complex environments. These vehicles are programed ...
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Cooperative micro-robotic scent tracking vehicles are designed to collectively "sniff out" locations of high scent concentrations in unknown, geometrically complex environments. These vehicles are programed with guidance and control algorithms that allow inter cooperation among vehicles. In this paper, a cooperative guidance and control algorithm for scent tracking micro-robotic vehicles is presented. This algorithm is comprised of a sensory compensation sub-algorithm using point source cancellation, a guidance sub-algorithm using gradient descent tracking, and a control sub-algorithm using proportional feedback. The concepts of social rank and point source cancellation are new concepts introduced within. Simulation results for cooperative vehicles swarms are given. Limitations are discussed.
To solve the problems in guidance, navigation, and control for an autonomous robot, its accurate positioning and localization are needed. Two or more different sensors are often used to obtain reliable data useful for...
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To solve the problems in guidance, navigation, and control for an autonomous robot, its accurate positioning and localization are needed. Two or more different sensors are often used to obtain reliable data useful for control system. Extended Kalman Filter (EKF) is widely used to fuse those data to obtain one optimal result. The signals used during navigation cannot be always considered as white noise signals. On the other hand, colored signals will cause the EKF to diverge. This paper presents the data fusion system for mobile robot navigation. Odometry and sonar signals are fused using Extended Kalman Filter (EKF) and Adaptive Fuzzy Logic System (AFLS). The AFLS was used to adapt the gain and therefore prevent the Kalman filter divergence. The fused signal is more accurate than any of the original signals considered separately. The enhanced, more accurate signal is used to guide and navigate the robot.
A neuro controller for high precision manoeuvring of underwater vehicles require special attention to a number of factors including thruster and vehicle’s nonlinearities, couplings which exist between various degrees...
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A neuro controller for high precision manoeuvring of underwater vehicles require special attention to a number of factors including thruster and vehicle’s nonlinearities, couplings which exist between various degrees of freedom as well as effects of the sea currents. The neuro control system for underwater vehicle maneouvring described here is based on the conventional controller supported with the so called adaptive neural network.
The author has studied on information-oriented maneuvering assistance/guidance system for vessels entering and leaving port and has tried to develop the system by using current advanced CNS(Communication, Navigation a...
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The author has studied on information-oriented maneuvering assistance/guidance system for vessels entering and leaving port and has tried to develop the system by using current advanced CNS(Communication, Navigation and Surveillance) technologies. This system consists of following five functions; 1) Pilotage Planning, 2) Network between a Shore-based site and Vessels, 3) Mission Rehearsal, 4) Motion Monitoring, 5) Track Database. In this paper, the concepts of this system, the system configuration, results of the system trial, the algorithm of Pilotage Planning are described.
This study is the fruit of a cooperative research action between the RENAULT Research Division and the Fuzzy Logic Group (Groupe Logique Floue) at the University of Technology of Compiegne. Emphasizing the driver'...
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ISBN:
(纸本)0780347781
This study is the fruit of a cooperative research action between the RENAULT Research Division and the Fuzzy Logic Group (Groupe Logique Floue) at the University of Technology of Compiegne. Emphasizing the driver's comfort, our main objective was to design and tune an active driver assistance enabling and ensuring automatic guidance, while at any time allowing the driver to take over control of his vehicle. A Fuzzy Logic Controller (FLC) has been developed and implemented on a RENAULT SAFRANE, ensuring the transversal control of the car.
An active video sensor system for determining target range and attitude was flown on STS-87. The Video guidance Sensor (VGS), developed at NASA's Marshall Space Flight Center (MSFC), demonstrated its capability in...
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ISBN:
(纸本)0819428299
An active video sensor system for determining target range and attitude was flown on STS-87. The Video guidance Sensor (VGS), developed at NASA's Marshall Space Flight Center (MSFC), demonstrated its capability in space and collected performance data. The VGS was designed to provide near-range sensor data as part of an automatic rendezvous and docking system. The sensor determines the relative positions and attitudes between the active sensor and the passive target. The VGS uses laser diodes to illuminate retro-reflectors in the target, a solid-state camera to detect the return from the target, and a frame grabber and digital signal processor to convert the video information into the relative positions and attitudes. The system is designed to operate with the target within a relative azimuth of +/- 9.5 degrees and a relative elevation of +/- 7.5 degrees. The system will acquire and track the target within the defined field-of-view between 1.5 meters and 110 meters range, and the VGS is designed to acquire at relative attitudes of +/- 10 degrees in pitch and yaw and at any roll angle. The sensor outputs the data at 5 Hz, and the target and sensor software and hardware have been designed to permit two independent sensors to operate simultaneously. This allows for redundant sensors. The data from the flight experiment includes raw video data from the VGS camera, relative position and attitude measurements from the VGS, solar angle data, and Remote Manipulator System (RMS) position data to correlate with the VGS data. The experiment was quite successful acid returned significant verification of the sensor's capabilities. The experience gained from the design and flight of this experiment will lead to improved video sensors in the future.
The Acquisition ofEnglish Unaccusative Verbs of Existence I Appearanceby Chinese L2 LearnersThe present study is an attempt at tackling the learning problems in the acquisition of English unaccusative verbs of F/A (Ex...
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The Acquisition of
English Unaccusative Verbs of Existence I Appearance
by Chinese L2 Learners
The present study is an attempt at tackling the learning problems in the acquisition of English unaccusative verbs of F/A (Existence/Appearance) by Chinese learners by answering the following four questions: (1) What are the factors that may influence the acquisition of unaccusative verbs of F/A by Chinese learners? (2) Given the influence of the identified factors, how can the process of acquisition be described? (3) Do the Chinese L2 learners acquire these verbs in the way as predicted? If no, how the process of acquisition might be described? (4) To what extent is the observed process of acquisition the result of influence of the identified factors? Are there any other possible factors that may contribute to the acquisition process?
Based on a review of the current studies on overpassivization of English unaccusative verbs, our research subclssified English verbs of F/A into 4 verb types in the framework of the Lexical Semantic Structure Theoiy. In the light of a linguistic analysis between English F/A verbs and their Chinese counterparts and the Markedness Differential Hypothesis, 3 hypotheses were made about the acquisition pattern of E/A verbs by Chinese L2 learners.
Then a GJ test was conducted to investigate the knowledge about the unaccusativity in E/A verbs of 90 subjects at 3 L2 proficiency levels and 10 native speakers. The results revealed that the acquisition route followed by Chinese learners in learning English F/A verbs is: the verb die 梸 verbs of Occurrence
verbs of Existence and verbs of Appearance. Animacy (the semantic feature of the NP arguments specified by EIA verbs) influenced the learning of F/A verbs through interaction with the semantic element of some verb types. The findings also suggested that fossilization is an important fe
In this paper, a modified receding horizon guidance law (MRHG) is proposed which can be a proper guidance law when the accurate time-to-go is available only for a short time before the final time. In the proposed MRHG...
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In this paper, a modified receding horizon guidance law (MRHG) is proposed which can be a proper guidance law when the accurate time-to-go is available only for a short time before the final time. In the proposed MRHG, RHG is used before the accurate time-to-go is available and after that, OGL is used until the missile intercepts the target using the accurate time-to-go given for a short time. The proposed MRHG makes the lateral miss distance (MD) below the pre-described value before the accurate time-to-go is available and makes the terminal MD zero using the accurate time-to-go even in the presence of target maneuvers and an initial relative normal velocity between the target and the missile. Through simulation, the performance of MRHG is illusrtated in terms of the terminal MD the lateral MD and the missile normal acceleration.
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