guidance system, which is an integral part of missile flight control system, plays a key role in achieving a desired performance subjected to various criteria. This paper focuses on the design of terminal impact angle...
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guidance system, which is an integral part of missile flight control system, plays a key role in achieving a desired performance subjected to various criteria. This paper focuses on the design of terminal impact angle constrained guidance laws, against maneuvering targets, for three-dimensional engagements. Impact angles are defined by the elevation and azimuth angles of line-of-sight with respect to the inertial frame of reference. The derivation of guidance strategies are performed with the nonlinear coupled engagement kinematics using dynamic inversion and sliding mode control techniques. The proposed guidance laws are applicable even for large heading angle errors. The comparative study of performance of both guidance laws is done using numerical simulations for various engagement scenarios. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
With the vigorous development of preschool education, more and more experts and scholars pay attention to the educational value of outdoor sports games in kindergarten and the effectiveness of kindergarten teachers...
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ISBN:
(纸本)9781510884632
With the vigorous development of preschool education, more and more experts and scholars pay attention to the educational value of outdoor sports games in kindergarten and the effectiveness of kindergarten teachers' guidance strategies. By conducting action research on the current situation of kindergarten teachers' guidance strategies in outdoor sports games in Xi'an, this paper analyzes the current situation of teachers' guidance strategies, and puts forward suggestions and countermeasures for improving kindergarten teachers' guidance strategies in outdoor sports games, so as to realize the educational value of outdoor sports games.
In interactive instance segmentation, users give feedback to iteratively refine segmentation masks. The user-provided clicks are transformed into guidance maps which provide the network with necessary cues on the wher...
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ISBN:
(纸本)9781728132945
In interactive instance segmentation, users give feedback to iteratively refine segmentation masks. The user-provided clicks are transformed into guidance maps which provide the network with necessary cues on the whereabouts of the object of interest. guidance maps used in current systems are purely distance-based and are either too localized or non-informative. We propose a novel transformation of user clicks to generate content-aware guidance maps that leverage the hierarchical structural information present in an image. Using our guidance maps, even the most basic FCNs are able to outperform existing approaches that require state-of-the-art segmentation networks pre-trained on large scale segmentation datasets. We demonstrate the effectiveness of our proposed transformation strategy through comprehensive experimentation in which we significantly raise state-of-the-art on four standard interactive segmentation benchmarks.
Under the influence of the continuous accelerating of urbanization process, urban roads have achieved rapid development, which directly promoted the local economic development level and the people's living standar...
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Under the influence of the continuous accelerating of urbanization process, urban roads have achieved rapid development, which directly promoted the local economic development level and the people's living standards. Based on this situation, people began to pay more attention to the comfort and environmental protection of daily production and living environment. Therefore, under the influence of various related factors, the Sponge City theory was derived and began to bring its role into full play, especially had a more and more prominent guiding role in the urban road landscape planning and design. Hereby, this paper mainly conducted a detailed analysis on the scientific planning and design of urban road greening landscape under the guidance of Sponge City.
In recent years, Synthetic Aperture Radar (SAR) has been widely used in guidance systems due to its high imaging quality and other superior functions. As the basis of system, SAR image registration has a direct impact...
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ISBN:
(纸本)9781538637586
In recent years, Synthetic Aperture Radar (SAR) has been widely used in guidance systems due to its high imaging quality and other superior functions. As the basis of system, SAR image registration has a direct impact on guidance precision. However, due to some inherent characteristics, especially the polarization and speckle noise, we need to adopt more effective approach to achieve the high precision and low computation of SAR guidance system than other optical image based systems. Therefore, in this paper, first, we implement NLM (Non-local Means) filter to improve the image quality damaged by speckle. Then, at feature detection and description stage, we adopt well-known FAST (Features from Accelerated Segment Test) and gradient-based binary descriptors, LDB (Local Difference Binary), to overcome strict real-time requirement and polarization phenomenon. Finally, at matching stage, in order to increase the number of correct pairs, the FSC (Fast Sample Consensus) is used to discard outliers matched by Hamming distance. And the transformation parameters could be estimated with affine model. To evaluate the performance of algorithms, three comparative experiments have been accomplished. The results demonstrate a good performance of our proposed method.
Aiming at the problem that single sensor cannot balance the distance of guidance and accuracy, the paper proposes a remote guidance method for UAV (Unmanned Aerial Vehicle) based on multi-sensors. This paper first int...
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ISBN:
(纸本)9781728137933
Aiming at the problem that single sensor cannot balance the distance of guidance and accuracy, the paper proposes a remote guidance method for UAV (Unmanned Aerial Vehicle) based on multi-sensors. This paper first introduces the remote guidance and autonomous landing task. Then the hardware and control method are designed. The landing process is divided into two stages: the long-range and close-range. In order to take advantage of the characteristics of different sensors, GPS/IMU (Inertial Measurement Unit) hybrid guidance is used for long-range stage and visual guidance is used for close-range stage. The positioning and guidance method are also introduced in detail. In close- range stage, according to the requirements of accurate landing on mobile UGV (Unmanned Ground Vehicle), the vision guidance method based on Apriltag is proposed and the calculation of UAV attitude and relative distance is completed. EKF (Extended Kalman Filter) is used as the multi-sensors fusion method. Finally, the method is applied to a quadrotor and Mecanum UGV and an outdoor experiment is realized and analyzed. The experimental results show that the accuracy and real-time ability of the proposed method meet the requirements of UAV's landing on a mobile UGV from a long distance.
The goal of this study is to create a real-time guidance, navigation and control (GNC) framework for a fixed-wing aircraft (FWA) to perform various maneuvers in a vertical plane. This study offers a new approach for i...
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ISBN:
(纸本)9781538613542
The goal of this study is to create a real-time guidance, navigation and control (GNC) framework for a fixed-wing aircraft (FWA) to perform various maneuvers in a vertical plane. This study offers a new approach for improving the FWA autonomy by enabling real-time sensor data fusion, targeting and re-targeting capabilities, new analytical/numerical trajectory and attitude control solutions, and target-relative guidance. Existing FWA dynamical models are based on the traditional decoupling of their motion. This paper extends the utility of the concept of an instantaneous screw axis in guidance and control thereby promoting a new vision to general 6-degrees-of-freedom rigid body motion control. The existing flight vehicle guidance and control functions are mainly iterative and implicit, platform-specific, utilize pre-determined target states or way points, and executed typically utilizing the decoupled motion dynamical models. The research presented in this paper produces the GNC framework with the real-time target-relative guidance system, which is explicit and free of iterations, provide an onboard computation of the target states, executable for an uncoupled motion, and adjustable to various FWA and other unmanned aerial system platforms. An illustrative example is considered for a FWA maneuver in a vertical plane.
guidance, Navigation, and Control (GN&C) systems take data from the environment to create a mathematical representation of the system state. The system's guidance solution is then determined from this navigati...
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ISBN:
(纸本)9781538616475
guidance, Navigation, and Control (GN&C) systems take data from the environment to create a mathematical representation of the system state. The system's guidance solution is then determined from this navigation solution and is typically a minimization of some objective weight function, J. This objective function is a time, cost, weight, or other physically realizable quantity. In this paper we show a method to create a guidance solution based upon system risk for a system's goal. The methodology presented uses a goal to create a situation. The situation assessment creates a situation model whose risk can be determined. The projection of this into the future then creates a trajectory for the system to follow. A simulation of using nautical vessels is shown and compared to traditional optimization methods.
With the increased popularity of cameras, more and more people are interested in learning photography. People are willing to invest in expensive cameras as a medium for their artistic expression, but few have access t...
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ISBN:
(纸本)9781450359498
With the increased popularity of cameras, more and more people are interested in learning photography. People are willing to invest in expensive cameras as a medium for their artistic expression, but few have access to in-person classes. Inspired by critique sessions common in in-person art practice classes, we propose design principles for creative learning. My dissertation research focuses on designing new interfaces and interactions that provide contextual in-camera feedback to aid users in learning visual elements of photography. We interactively visualize results of image processing algorithms as additional information for the user to make more informed and intentional decisions during capture. In this paper, we describe our design principles, and apply these principles in the design of two guided photography interfaces: one to explore lighting options for a portrait, and one to refine contents and composition of a photo.
The university stage is an important period for student growth and personality *** sports is the last stop for students to study at school and the highest level of physical education in ***,it is necessary to grasp th...
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The university stage is an important period for student growth and personality *** sports is the last stop for students to study at school and the highest level of physical education in ***,it is necessary to grasp the main body status of physical education classroom teaching;strengthening students' teaching and guiding learning methods is the need to cultivate students' lifelong physical education *** article further explores the guidance of learning methods to help sports practitioners play an important role in the classroom in a more flexible and free way,thus improving the effectiveness of physical education.
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