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PDE solution to UAV/UGV trajectory planning problem by spatio-temporal estimation during wildfires

Chinese Journal of Aeronautics 2021年第5期34卷 601-616页

作者： Mohammadreza RADM ANESH Balaji SHARMA Manish KUMAR Donald FRENCH aerial mobility group NASA Jet Propulsion Lcib(JPL)Pasadena 91016USA Mathworks BuffaloNew YorkUSA Department of Mechanical and Material Engineering.University of Cincinnati Cincinnati 45221USA Department of Mathematical Sciences University of CincinnatiCincinnati 45221USA

Unmanned aerial Vehicles(UAVs)and Unmanned Ground Vehicles(UGVs)have been used in research and development community due to their strong potential in high-risk *** of the most important civilian implementations of UAV/UGV cooperative path planning is delivering medical or emergency supplies during disasters such as wildfires,the focus of this ***,wildfires themselves pose risk to the UAVs/UGVs and their paths should be planned to avert the risk as well as complete the *** this paper,wildfire growth is simulated using a coupled Partial Differential Equation(PDE)model,widely used in literature for modeling wildfires,in a grid environment with added process and measurement *** principles of Proper Orthogonal Decomposition(POD),and with an appropriate choice of decomposition modes,a low-dimensional equivalent fire growth model is obtained for the deployment of the space-time Kalman Filtering(KF)paradigm for estimation of wildfires using simulated *** KF paradigm is then used to estimate and predict the propagation of wildfire based on local data obtained from a camera mounted on the *** information is then used to obtain a safe path for the UGV that needs to travel from an initial location to the final position while the UAV’s path is planned to gather information on *** planning of both UAV and UGV is carried out using a PDE based method that allows incorporation of threats due to wildfire and other obstacles in the form of risk *** results from numerical simulation are presented to validate the proposed estimation and path planning methods.

关键词： State-estimation Trajectory planning UAV UGV Wild-fire

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Disordered Multi-view Registration Method Based on the Soft Trimmed Deep Network

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Journal of Geodesy and Geoinformation Science 2023年第4期6卷 13-26页

作者： Rui GUO Yuanlong SONG Zhengyao WANG aerial Photography and Remote Sensing group Co. Ltd.Xi’an 710199China

Compared with the pair-wise registration of point clouds,multi-view point cloud registration is much less *** this dissertation,a disordered multi-view point cloud registration method based on the soft trimmed deep network is *** this method,firstly,the expression ability of feature extraction module is improved and the registration accuracy is increased by enhancing feature extraction network with the point pair ***,neighborhood and angle similarities are used to measure the consistency of candidate points to surrounding *** combining distance consistency and high dimensional feature consistency,our network introduces the confidence estimation module of registration,so the point cloud trimmed problem can be converted to candidate for the degree of confidence estimation problem,achieving the pair-wise registration of partially overlapping point ***,the results from pair-wise registration are fed into the model fusion to achieve the rough registration of multi-view point ***,the hierarchical clustering is used to iteratively optimize the clustering center model by gradually increasing the number of clustering categories and performing clustering and registration *** method achieves rough point cloud registration quickly in the early stage,improves the accuracy of multi-view point cloud registration in the later stage,and makes full use of global information to achieve robust and accurate multi-view registration without initial value.

关键词： soft trimmed deep network point cloud registration hierarchical clustering

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Stability analysis of linear/nonlinear switching active disturbance rejection control based MIMO continuous systems

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Journal of Systems Engineering and Electronics 2021年第4期32卷 956-970页

作者： WAN Hui QI Xiaohui LI Jie Department of Unmanned aerial Vehicle Engineering Army Engineering University of PLAShijiazhuang 050003China The 32nd Research Institute China Electronics Technology Group CorporationShanghai 201800China

In this paper,a linear/nonlinear switching active disturbance rejection control(SADRC)based decoupling control approach is proposed to deal with some difficult control problems in a class of multi-input multi-output(MIMO)systems such as multi-variables,disturbances,and coupling,***,the structure and parameter tuning method of SADRC is introduced into this *** on this,virtual control variables are adopted into the MIMO systems,making the systems *** the SADRC controller is designed for every *** this,a stability analyzed method via the Lyapunov function is proposed for the whole ***,some simulations are presented to demonstrate the anti-disturbance and robustness of SADRC,and results show SADRC has a potential applications in engineering practice.

关键词： linear/nonlinear switching active disturbance rejection control(SADRC) multi-input multi-output(MIMO)continuous system decoupling control stability analysis

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Safety analysis of wheel brake system based on STAMP/STPA and Monte Carlo simulation

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Journal of Systems Engineering and Electronics 2018年第6期29卷 1327-1339页

作者： HU Jianbo ZHENG Lei XU Shukui Equipment Management and Unmanned aerial Vehicle Engineering College Air Force Engineering UniversityXi’an 710051China The 28th Research Institute of China Electronic Technology group Corporation Nanjing 210000China

The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with traditional probability techniques based on the linear chain of events. However, it could not comprehensively analyze system safety problems, especially in operating environment, interaction of subsystems, and human factors. Thus,we consider system safety as a control problem based on the system-theoretic accident model, the processes(STAMP) model and the system theoretic process analysis(STPA) technique to compensate the deficiency of traditional techniques. Meanwhile,system safety simulation is considered as system control simulation, and Monte Carlo methods are used which consider the range of uncertain parameters and operation deviation to quantitatively study system safety influence factors in control simulation. Firstly,we construct the STAMP model and STPA feedback control loop of the wheel brake system based on the system functional requirement. Then four unsafe control actions are identified, and causes of them are analyzed. Finally, we construct the Monte Carlo simulation model to analyze different scenarios under disturbance. The results provide a basis for choosing corresponding process model variables in constructing the context table and show that appropriate brake strategies could prevent hazards in aircraft landing taxiing.

关键词： safety analysis landing taxiing system-theoretic accident model and processes(STAMP) model and system theoretic process analysis(STPA)(STAMP/STPA) feedback control loop Monte Carlo simulation

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A New Hybrid Reliability Index Definition and Its Application to the Structure Buckling Reliability Analysis of Supercavitating Projectiles

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Journal of Shanghai Jiaotong university(Science) 2016年第4期21卷 467-471页

作者：周凌李志涛韩景壮张楠 Department of Unmanned aerial Vehicle Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China North Norinco group Beijing 100089 China

As structure buckling problems easily arise when supercavitating projectiles operate with high underwater velocity, it is necessary to perform structure buckling reliability analysis. Now it is widely known that probabilistic and non-probabilistic uncertain information exists in engineering analysis. Based on reliability comprehensive index of multi-ellipsoid convex set, probabilistic uncertain information is added and transferred into non-probabilistic interval variable. The hybrid reliability is calculated by a combined method of modified limit step length iteration algorithm(MLSLIA) and Monte-Carlo method. The results of engineering examples show that the convergence of MLSLIA is better than that of limit step length iteration algorithm(LSLIA). Structure buckling hybrid reliability increases with the increase of ratio of base diameter to cavitator diameter, and decreases with the increase of initial launch velocity. Also the changes of uncertain degree of projectile velocity and cavitator drag coefficient affect structure buckling hybrid reliability index obviously. Therefore, uncertain degree of projectile velocity and cavitator drag coefficient should be controlled in project for high structure buckling reliability.

关键词： supercavitating projectile structure buckling hybrid reliability modified limit step length iteration algorithm (MLSLIA) Monte-Carlo method

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Comparative study on high temperature deformation behavior and processing maps of Mg-4Zn-1RE-0.5Zr alloy with and without in-situ sub-micron sized TiB2 reinforcement

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Journal of Magnesium and Alloys 2022年第12期10卷 3520-3541页

作者： S.K.Sahoo S.K.Panigrahi Department of Mechanical Engineering Indian Institute of Technology MadrasChennai-600036India Applied Magnesium Research group Center of Excellence in Materials and Manufacturing for Futuristic Mobility Indian Institute of Technology MadrasChennai-600036India

Mg-4Zn-1RE-0.5Zr (ZE41) Mg alloy is extensively used in the aerospace and automobile *** order to improve the applicability and performance,this alloy was engineered with in-situ Ti B2reinforcement to form Ti B2/ZE41 *** high temperature deformation behavior and manufacturability of the newly developed Ti B2/ZE41 composite and the parent ZE41 Mg alloy were studied via establishing constitutive modeling of flow stress,deformation activation energy and processing map over a temperature range of 250℃-450℃ and strain rate range of 0.001 s-1-10 *** predicted flow stress behavior of both materials were found to be well consistent with the experimental values.A significant improvement in activation energy was found in Ti B2/ZE41 composite (171.54 k J/mol) as compared to the ZE41 alloy (148.15 k J/mol) due to the dispersed strengthening of in-situ Ti *** processing maps were developed via dynamic material modeling.A wider workability domain and higher peak efficiency (45%) were observed in Ti B2/ZE41 composite as compared to ZE41 alloy (41%).The Dynamic recrystallization is found to be the dominating deformation mechanism for both materials;however,particle stimulated nucleation was found to be an additional mode of deformation in Ti B2/ZE41 *** twinning and stress induced cracks were observed in both the materials at low temperature and high strain rate.A narrow range of instability zone is found in the present Ti B2/ZE41 composite among the existing published literature on Mg based *** detailed microstructural characterization was carried out in both workability and instability domains to establish the governing deformation mechanisms.

关键词： ZE41 Mg composite In-situ TiB2 particles ZE41 Mg alloy Constitutive equations Processing map Dynamic recrystallization

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The effect of ride experience on changing opinions toward autonomous vehicle safety

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Communications in Transportation Research 2021年第1期1卷 7-15页

作者： Xiaowei Shi Zhen Wang Xiaopeng Li Mingyang Pei Department of Civil and Environmental Engineering University of South FloridaTampaFL33620USA School of Information Engineering Chang'an UniversityShaanxiChina Automatic Control group and Urban mobility Systems group Chalmers University of TechnologyGothenburgSE-41296Sweden

Autonomous vehicles(AVs)are a promising emerging technology that is likely to be widely deployed in the near ***'s perception on AV safety is critical to the pace and success of deploying the AV *** studies found that people's perceptions on emerging technologies might change as additional information was *** investigate this phenomenon in the AV technology context,this paper conducted real-world AV experiments and collected factors that may associate with people's initial opinions without any AV riding experience and opinion change after a successful AV ride.A number of ordered probit and binary probit models considering data heterogeneity were employed to estimate the impact of these factors on people's initial opinions and opinion *** study found that people's initial opinions toward AV safety are significantly associated with people's age,personal income,monthly fuel cost,education experience,and previous AV ***,the factors dominating people's opinion change after a successful AV ride include people's age,personal income,monthly fuel cost,daily commute time,driving alone indicator,willingness to pay for AV technology,and previous AV *** results provide important references for future implementations of the AV ***,based on the inconsistent effects for variables across different models,suggestions for future transportation survey designs are provided.

关键词： Autonomous vehicle Technology acceptance Safety Ordered probit model Binary probit model

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Investigation into machining performance of microstructurally engineered in-situ particle reinforced magnesium matrix composite

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Journal of Magnesium and Alloys 2023年第3期11卷 916-935页

作者： S.K.Sahoo B.N.Sahoo S.K.Panigrahi Department of Mechanical Engineering Indian Institute of Technology MadrasChennai 600036India Applied Magnesium Research group Center of Excellence in Materials and Manufacturing for Futuristic MobilityIndian Institute of Technology MadrasChennai 600036India Department of Mechanical Engineering Sardar Vallabhbhai National Institute of TechnologySurat 395007India

Magnesium and magnesium in-situ composites have significant potential in the application of design and manufacturing for automotive and aerospace industries because of their high specific strength and reduced fuel *** there are many challenges for machining of Mg based alloys and composites because of the high tendency of fire and *** challenges can be minimized through microstructural *** this present study,the machining performances of AZ91 Mg alloy and in-situ hybrid TiC+TiB_(2)reinforced AZ91 metal matrix composite was *** effectβ-Mg_(17)Al_(12)phases and grain refinement with and without in-situ particles on machinability were studied through microstructural engineering via aging and friction stir *** end milling operation was carried out at different cutting speeds ranging from 25 mm/min to 90 mm/min under dry environment by using an AlTiN-coated tungsten carbide *** optimum cutting speed for machining was found to be 75 mm/min based on the surface roughness values of all conditioned *** base material with dendritic microstructure was found to have poor machinability in terms of inadequate surface finish and edge-burrs *** combined effect of in-situ TiC+TiB_(2)particles addition and grain refinement enhanced the machining performance of the material with superior surface finish,negligible edge-burr formation and better tool wear *** influence of in-situ TiC+TiB_(2)particles,β-Mg_(17)Al_(12)phases and grain refinement on machining characteristics are explained based on the tool wear mechanisms,chip behavior and machining induced affected zone.

关键词： Magnesium In-situ composite End-milling Tool wear Chip morphology

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Experimental Study on the Expansion Uniformity of Armature

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Journal of Beijing Institute of Technology 2009年第1期18卷 56-59页

作者：何远航吴碧马月芬张庆明 State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Teaching and Research Center of Unmanned aerial Vechicle Artillery Academy of PLA

A measurement system has been developed based on high-precision printed probes in printed circuit board （PCB） and steep rising-time probe adapters, which can be applied to study the expansion uniformity of armature in a helical magnetic flux compression generator （HFCG）. The influences of wall thickness and initiation position on the expansion uniformity of armature in HFCG were experimentally investigated. The results show that the armature with thinner wall thickness will easily rupture due to the high pressure of detonation products inside, the armature with larger wall thickness will easily crack due to the tensile stress on the outer surface of the wall, the influence of the end effect on the expansion uniformity can be ignored if the distance between the first group of probe and the initiation point is more than 3 times the armature diameter.

关键词： helical flux compression generator expansion uniformity of armature printed probes in PCB

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A crystal plasticity based approach to establish role of grain size and crystallographic texture in the Tension–Compression yield asymmetry and strain hardening behavior of a Magnesium–Silver–Rare Earth alloy

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Journal of Magnesium and Alloys 2022年第9期10卷 2546-2562页

作者： Sourav Mishra F.Khan S.K.Panigrahi Department of Mechanical Engineering Indian Institute of Technology MadrasChennai 600036Tamil NaduIndia Applied Magnesium Research group Centre for Materials and Manufacturing for Futuristic MobilityIndian Institute of Technology MadrasChennai 600036Tamil NaduIndia School of Mechanical Engineering Vellore Institute of TechnologyVellore 632014Tamil NaduIndia

Existence of tension–compression yield asymmetry is a serious limitation to the load bearing capablities of Magnesium alloys in a number of light weight structural *** present work is aimed at nullifying the tension to compression asymmetry problem and strain hardening anomalies in a Magnesium–Silver–Rare Earth alloy by engineering different levels of microstructural conditions via friction stir processing and post process *** existence and extent of yield asymmetry ratio in the range of microstructural conditions was experimentally obtained through quasistatic tensile and compression *** yield asymmetry problem was profoundly present in specimens of coarse grained microstructures when compared to their fine grained and ultra fine grained *** impact of the microstructure and associated mechanisms of plasticity on the macroscopic strain hardening behavior was established by Kock–Mecking’s *** plasticity simulations using Viscoplastic Self Consistency approach revealed the consequential role of extension twinning mechanism for the existence of yield asymmetry and anomalies in strain hardening *** was especially dominant with coarsening of grain *** Microscopy and characterization were conducted thoroughly in partially deformed specimens to confirm the predictions of the above *** role of crystallographic texture for inducing the polarity to Tension–Compression yield asymmetry was corroborated.A critical grain size in Magnesium–Silver–Rare earth alloy was hereby established which could nullify influences of extension twinning in yield asymmetry ratio.

关键词： Magnesium silver rare earth alloy Friction stir processing Ultrafine-grained microstructure Tension to compression yield strength asymmetry Crystallographic texture Strain hardening Kock mecking plots Visco plastic self consistency

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