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Predictive Motion Planning with Pipelined Feature-Based Obstacle Avoidance

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2016年第4期39卷 967-975页

作者： Seiferth, Christoph Joos, Alexander Frangenberg, Michael Fichter, Walter Univ Stuttgart Inst Flight Mech & Control D-70569 Stuttgart Germany

An efficient method for the approximate solution of a finite-horizon constrained optimal control problem was proposed that uses quantized and discretized control candidates in such a way that a real-time implementation on a small onboard computer is feasible. For obstacle or collision avoidance, an algorithm using predicted trajectory points and visible three-dimensional features in a point cloud was presented that is suitable for a parallel and pipelined implementation on a field-programmable gate array. This allows for a very large number of obstacles to be checked by using raw sensor data only without further processing. The second option of an obstacle cost function uses a barrier function approach. It is designed so that the cost tends to infinity if the distance between a predicted trajectory point and an obstacle approaches the minimum distance. Choosing this approach helps to influence the flown trajectory, even when the vehicle has a much greater distance to possible obstacles than the minimum distance, since features always introduce costs on a trajectory and not only if the predicted trajectory violates the minimum distance requirement.

关键词： Model Predictive Control Motion Planning Field Programmable Gate Array Flight Testing Optimal Control Quaternions Onboard Computing navigation algorithm LIDAR VTOL

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Autonomous airborne refueling of unmanned air vehicles using the global positioning system

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JOURNAL OF AIRCRAFT 2007年第5期44卷 1670-1682页

作者： Khanafseh, Samer M. Pervan, Boris IIT Mech Mat & Aerosp Engn Dept Chicago IL 60616 USA

Autonomous airborne refueling requires that the position of the receiving aircraft relative to the tanker be known very accurately and in real time. To meet this need, highly precise carrier-phase differential global positioning system solutions are being considered as the basis for navigation. However, the tanker introduces severe sky blockage into the autonomous airborne refueling mission, which reduces the number of visible global positioning system satellites and hence degrades the positioning accuracy. In this paper, we analyze the autonomous airborne refueling navigation problem in detail, define an optimal navigation architecture, and quantify navigation system availability. As part of this work, a high-fidelity dynamic sky-blockage model is developed and used to plan autonomous airborne refueling flight tests. The flight tests were conducted to obtain time-tagged global positioning system and attitude data that were processed offline to validate the blockage model.

关键词： Differential Global Positioning System Air Vehicle Satellite Constellations Flight Test Cards In Flight Refueling Constellations GPS Satellites Vertical Dilution of Precision Inertial navigation System navigation algorithm

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Use of Cartesian-Coordinate Calibration for Satellite Relative-Motion Control

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2015年第9期38卷 1842-1846页

作者： Sinclair, Andrew J. Sherrill, Ryan E. Lovell, T. Alan Auburn Univ Dept Aerosp Engn 211 Davis Hall Auburn AL 36849 USA Engil Corp Engn & Program Management Group Eglin AFB FL USA Space Vehicles Directorate Air Force Res Lab Kirtland AFB NM 87117 USA

Presented as Paper 2014-0218 at the AAS/AIAA Space Flight Mechanics Meeting, Santa Fe, NM, 26-30 January 2014

关键词： Satellites Cartesian Coordinates Nonlinear Dynamics Orbital Elements Linear Quadratic Regulator Monte Carlo Simulation navigation algorithm Fuel Consumption Feedback Control Orbital Period

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Bearings-Only Guidance in Cis-Lunar Rendezvous

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2021年第10期44卷 1862-1874页

作者： D'Onofrio, Fabio Bucchioni, Giordana Innocenti, Mario Univ Pisa Dept Informat Engn Via Caruso 16 I-56122 Pisa Italy

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Directed, cylindric and radial Brownian webs

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ELECTRONIC JOURNAL OF PROBABILITY 2019年第none期24卷 1-48页

作者： Coupier, David Marckert, Jean-Francois Viet Chi Tran Univ Valenciennes CNRS LAMAV EA 4015 F-59313 Valenciennes 9 France Univ Bordeaux CNRS LaBRI UMR 5800 351 Cours Liberat F-33405 Talence France Univ Lille CNRS Lab P Painleve Dept MathUMR 8524 F-59000 Lille France

The Brownian web (BW) is a collection of coalescing Brownian paths (W-(x,W-t), (x, t) is an element of R-2) indexed by the plane. It appears in particular as continuous limit of various discrete models of directed forests of coalescing random walks and navigation schemes. Radial counterparts have been considered but global invariance principles are hard to establish. In this paper, we consider cylindrical forests which in some sense interpolate between the directed and radial forests: we keep the topology of the plane while still taking into account the angular component. We define in this way the cylindric Brownian web (CBW), which is locally similar to the planar BW but has several important macroscopic differences. For example, in the CBW, the coalescence time between two paths admits exponential moments and the CBW as its dual contain each a.s. a unique bi-infinite path. This pair of bi-infinite paths is distributed as a pair of reflected Brownian motions on the cylinder. Projecting the CBW on the radial plane, we obtain a radial Brownian web (RBW), i.e. a family of coalescing paths where under a natural parametrization, the angular coordinate of a trajectory is a Brownian motion. Recasting some of the discrete radial forests of the literature on the cylinder, we propose rescalings of these forests that converge to the CBW, and deduce the global convergence of the corresponding rescaled radial forests to the RBW. In particular, a modification of the radial model proposed in Coletti and Valencia is shown to converge to the CBW.

关键词： Brownian web navigation algorithm random spanning forests weak convergence of stochastic processes

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Course and heading changes in significant wind

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2007年第4期30卷 1168-1171页

作者： Rysdyk, Rolf Univ Washington Dept Aeronaut & Astronaut Autonomous Flight Syst Lab Seattle WA 98195 USA

USING straightforward differential geometry, this note presents a path formulation for maneuvering of a fixed wing aircraft in wind. The results accommodate analytical development and minimize heuristics of path-planning and decision-making algorithms. This note also makes the dynamic difference between course and heading rates explicit. This is significant for the coupling of guidance and navigation algorithms to the vehicle augmentation loops.

关键词： navigation algorithm Guidance Laws Aerodynamic Lift Fixed Wing Aircraft Yaw Airspeed Path Planning Standard Rate Turn Kalman Filter Closed Loop

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Precision Mars Entry navigation with Atmospheric Density Adaptation via Neural Networks

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JOURNAL OF AEROSPACE INFORMATION SYSTEMS 2024年第12期21卷 982-995页

作者： Giraldo-Grueso, Felipe Popov, Andrey A. Zanetti, Renato Univ Texas Austin Dept Aerosp Engn & Engn Mech Austin TX 78712 USA Univ Texas Austin Oden Inst Computat Engn & Sci Austin TX 78712 USA

Spacecraft entering Mars require precise navigation algorithms capable of accurately estimating the vehicle's position and velocity in dynamic and uncertain atmospheric environments. Discrepancies between the true Martian atmospheric density and the onboard density model can significantly impair the navigation performance. This work introduces a new approach to online filtering for Martian entry using a neural network to estimate atmospheric density and employing a "consider" analysis to account for the uncertainty in the estimate. The network is trained on an exponential atmospheric density model, and its parameters are dynamically adapted in real time to account for any mismatch between the true and estimated densities. The adaptation of the network is formulated as a maximum likelihood problem by leveraging the measurement innovations of the filter to identify optimal network parameters. Within the context of the maximum likelihood approach, incorporating a neural network enables the use of stochastic optimizers known for their efficiency in the machine learning domain. Performance comparisons are conducted against two online adaptive approaches, covariance matching and state augmentation and correction, in various realistic Martian entry navigation scenarios. The results show superior estimation accuracy compared to other approaches and precise alignment of the estimated density with a broad selection of realistic Martian atmospheres sampled from perturbed Mars Global Reference Atmospheric Model data.

关键词： Artificial Neural Network Machine Learning Unscented Kalman Filter Atmospheric Density Mars Atmospheric Entry navigation algorithm

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Distributed Estimator for Spacecraft Cooperative Localization

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2022年第6期45卷 1166-1171页

作者： Kaptui Sipowa, Hermann McMahon, Jay Univ Colorado Boulder Colorado Ctr Astrodynam Res Dept Aerosp Engn Sci Boulder CO 80309 USA

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Real-time predication and navigation on traffic congestion model with equilibrium Markov chain

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INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS 2018年第4期14卷

作者： Zheng, Yan Li, Yanran Own, Chung-Ming Meng, Zhaopeng Gao, Mengya Tianjin Univ Sch Comp Software Tianjin 300350 Peoples R China Tianjin Univ Coll Management & Econ Tianjin Peoples R China Tianjin Univ Tradit Chinese Med Tianjin Peoples R China

With the explosive growth of vehicles on the road, traffic congestion has become an inevitable problem when applying guidance algorithms to transportation networks in a busy and crowded city. In our study, the authors proposed an advanced prediction and navigation models on a dynamic traffic network. In contrast to the traditional shortest path algorithms, focused on the static network, the first part of our guiding method considered the potential traffic jams and was developed to provide the optimal driving advice for the distinct periods of a day. Accordingly, by dividing the real-time Global Positioning System data of taxis in Shenzhen city into 50 regions, the equilibrium Markov chain model was designed for dispatching vehicles and applied to ease the city congestion. With the reveals of our field experiments, the traffic congestion of city traffic networks can be alleviated effectively and efficiently, the system performance also can be retained.

关键词： Intelligent transportation system collaborative driving navigation algorithm traffic congestion Markov chain

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Behavior-Based navigation of an Autonomous Hexapod Robot Using a Hybrid Automaton

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JOURNAL OF INTELLIGENT & ROBOTIC SYSTEMS 2021年第2期102卷 29-29页

作者： Khazaee, Mostafa Sadedel, Majid Davarpanah, Atoosa Tarbiat Modares Univ Dept Mech Engn Tehran Iran

The hexapod robot is one of the important classes in legged robots due to its great potential to operate in complex settings with high stability and flexibility. However, few researches have investigated the navigation and autonomous locomotion of this type of robot. This paper concerns with the behavior-based control and navigation of an autonomous hexapod robot utilizing a hybrid automaton. Switching between the distinct behaviors is based on the sensory data, and no representation of the environment is included. Since these systems are likely to rise chattering phenomenon, a sliding mode including clockwise and counter-clockwise boundary following behaviors are considered between the goal attraction and obstacle avoidance modes to modify the automaton. The hybrid automaton undertakes the path planning of a reference point instead of the robot. Thus, in order to be able to implement the navigation algorithm, the hexapod robot is converted to a point mass robot within two transformations. A parameter study is also performed to investigate the effects of the controllers' design parameters on the performance of the navigation algorithm and robot. The results show that enhancing the smoothness of the robot's motion would deteriorate the precision in tracking the reference point and the reaction speed and vice versa. Moreover, simulation tests confirm the effectiveness of the navigation algorithm in generating the optimal path by perfectly switching between distinct modes as well as the capability of the robot to follow the reference point with an arbitrary gait. Furthermore, comparing the performance of the presented navigation strategy to that of similar algorithms, such as Bug and Potential field, yields a satisfying result.

关键词： Hybrid system navigation algorithm Autonomous Hexapod robot Mobile robot

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