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Sampling-efficient path planning and improved actor-critic-based obstacle avoidance for autonomous robots

Science China(Information Sciences) 2024年第5期67卷 197-214页

作者： Yefeng YANG Tao HUANG Tianqi WANG Wenyu YANG Han CHEN Boyang LI Chih-yung WEN department of aeronautical and aviation engineering The Hong Kong Polytechnic University Center for Control Theory and Guidance Technology Harbin Institute of Technology School of engineering The University of Newcastle Research Center for Unmanned Autonomous Systems The Hong Kong Polytechnic University

Autonomous robots have garnered extensive utilization in diverse fields. Among the critical concerns for autonomous systems, path planning holds paramount importance. Notwithstanding considerable efforts in its development over the years, path planning for autonomous systems continues to grapple with challenges related to low planning efficiency and inadequate obstacle avoidance response in a timely manner.This study proposes a novel and systematic solution to the path planning problem within intricate office buildings. The solution consists of a global planner and a local planner. To handle the global planning aspect, an adaptive clustering-based dynamic programming rapidly exploring random tree(ACDP-RRT) algorithm is proposed. ACDP-RRT effectively identifies obstacles on the map by leveraging geometric features.These obstacles are then represented as a collection of sequentially arranged convex polygons, optimizing the sampling region and significantly enhancing sampling efficiency. For local planning, a network decoupling actor-critic(ND-AC) algorithm is employed. The proposed ND-AC simplifies the local planner design process by integrating planning and control loops into a neural network(NN) trained via an end-to-end model-free deep reinforcement learning(DRL) framework. Moreover, the adoption of network decoupling(ND) techniques leads to an improved obstacle avoidance success rate when compared to conventional actor-critic(AC)-based methods. Extensive simulations and experiments are conducted to demonstrate the effectiveness and robustness of the proposed approach.

关键词： rapidly exploring random tree (RRT) adaptive clustering network decoupling actor critic (AC) path planning

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Automation 5.0:The Key to Systems Intelligence and Industry 5.0

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IEEE/CAA Journal of Automatica Sinica 2024年第8期 1723-1727页

作者： Ljubo Vlacic Hailong Huang Mariagrazia Dotoli Yutong Wang Petros A.Ioannou Lili Fan Xingxia Wang Raffaele Carli Chen Lv Lingxi Li Xiaoxiang Na Qing-Long Han Fei-Yue Wang the Beijing Huairou Academy of Parallel Sensing the School of Mechanical and Aerospace engineering Nanyang Technological University the department of Electrical and Computer engineering Purdue School of Engineering and Technology Indiana University-Purdue University Indianapolis the department of engineering University of Cambridge the School of Science Computing and Engineering Technologies Swinburne University of Technology the State Key Laboratory for Management and Control of Complex Systems Chinese Academy of Sciences the Dazhou Artificial Intelligence institute the Faculty of Innovation engineering Macau University of Science and Technology IEEE the institute of Intelligent and Integrated Systems and the School of engineering and Built Environment Griffith University the department of aeronautical and aviation engineering The Hong Kong Polytechnic University the department of Electrical and Information engineering Polytechnic of Bari the State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of Automation Chinese Academy of Sciences the Qingdao Academy of Intelligent Industries the department of Electrical engineering-Systems University of Southern California the School of Automation Beijing Institute of Technology the School of Artificial Intelligence University of Chinese Academy of Sciences

AUTOMATION has come a long way since the early days of mechanization, i.e., the process of working exclusively by hand or using animals to work with machinery. The rise of steam engines and water wheels represented the first generation of industry, which is now called Industry 1.0. Subsequently, Industry 2.0 witnessed the development of electric power and assembly lines.

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A theoretical method for solving shock relations coupled with chemical equilibrium and its applications

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Chinese Journal of Aeronautics 2022年第6期35卷 47-62页

作者： Zijian ZHANG Chihyung WEN Wenshuo ZHANG Yunfeng LIU Zonglin JIANG department of aeronautical and aviation engineering The Hong Kong Polytechnic UniversityHong KongChina institute of Mechanics Chinese Academy of SciencesBeijing 100190China School of engineering Science University of Chinese Academy of SciencesBeijing 100049China

In this study,a theoretical method is proposed to solve shock relations coupled with chemical equilibrium.Not only shock waves in dissociated flows but also detonation waves in combustive mixtures can be solved.The global iterative solving process is specially designed to mimic the physical and chemical process in reactive shock waves to ensure good stability and fast convergence in the proposed method.Within each global step,the single-variable equations of normal and oblique shock relations are derived and solved with the Newton iteration method to reduce the complexity of the problems,and the minimization of free energy method of NASA(National Aeronautics and Space Administration)is adopted to solve equilibrium compositions.It is demonstrated that the convergent process is stable and very close to the real chemical-kinetic process,and high accuracy is achieved in the solutions of normal and oblique reactive shock waves.Moreover,the proposed theoretical method has also been applied to many problems associated with reactive shocks,including the stability of oblique detonation wave,bow detonation over a sphere,and shock reflection in dissociated air.The great importance of using chemical equilibrium to theoretically predict the theoretical range of the wedge angle for a standing oblique detonation wave(the standing window of the oblique detonation wave),the stand-off distance of bow detonation wave and the transition criterion of shock reflection in dissociated air with high accuracy have been addressed.

关键词： Chemical equilibrium Detonation Dissociated air Shock relation Theoretical solution

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Broadband design of acoustic metasurfaces for the stabilization of a Mach 4 boundary layer flow

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Advances in Aerodynamics 2022年第1期4卷 286-303页

作者： Rui Zhao Xiao Liu Chihyung Wen Xiaoyong Wang School of Aerospace engineering Beijing Institute of TechnologyBeijing100081China department of aeronautical and aviation engineering The Hong Kong Polytechnic UniversityHong KongChina State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of Sciences100190BeijingChina

A piecewise acoustic metasurface is designed to suppress the first mode while marginally amplifying the Mack second mode in a Mach 4 flat-plate boundary layer(BL)flow.The results of linear stability theory(LST)and the eN method demonstrate the stabilization effect and transition delay performance,respectively.However,the direct numerical simulation(DNS)results indicate that the designed broadband acoustic metasurface actually weakly excites the first mode with a slightly larger fluctuating pressure amplitude at the surface,which is in contrast to the analysis of LST.The discrepancies are found to lie in the‘roughness’effect caused by the recirculation zones inside the microslits and the alternating expansion and compression waves induced at the slit edges,which significantly amplifies the first mode.For further clarification of the competitive mechanism between the acoustic stabilization and‘roughness’destabilization effects of metasurfaces on the first mode,a carefully designed metasurface is installed at the maximum growth rate region,which excites the first mode on the metasurface but inhibits its development downstream.

关键词： Boundary layer stabilization Acoustic metasurfaces Mack modes High-speed flow

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Graphene and MXene-based porous structures for multifunctional electromagnetic interference shielding

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Nano Research 2023年第1期16卷 1387-1413页

作者： Xi Shen Jang-Kyo Kim department of aeronautical and aviation engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong 999077China School of Mechanical and Manufacturing engineering University of New South WalesSydneyNSW 2052Australia The Research institute for Sports Science and Technology The Hong Kong Polytechnic UniversityHung HomHong Kong 999077China

Electrically conductive porous structures are ideal candidates for lightweight and absorption-dominant electromagnetic interference(EMI)shielding.In this review,we summarize the recent progress in developing porous composites and structures from emerging two-dimensional(2D)graphene and MXene nanosheets for EMI shielding applications.Important properties contributing to various energy loss mechanisms are probed with a critical discussion on their correlations with EMI shielding performance.Technological approaches to constructing bulk porous structures,such as 2D porous films,three-dimensional(3D)aerogels and foams,and hydrogels,are compared to highlight important material and processing parameters required to achieve optimal microstructures.A comprehensive comparison of EMI shielding performance is also carried out to elucidate the effects of different assembly techniques and microstructures.Distinctive multifunctional applications in adaptive EMI shielding,mechanical force attenuation,thermal management,and wearable devices are introduced,underlining the importance of unique compositions and microstructures of porous composites.The process–structure–property relationships established in this review would offer valuable guidance and insights into the design of lightweight EMI shielding materials.

关键词： porous composite graphene MXene electrical conductivity electromagnetic interference(EMI)shielding

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Real-time target recognition system simulation based on laser near-field detection

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Optoelectronics Letters 2009年第4期5卷 299-303页

作者：于晓亮马惠敏肖剑 department of Electronic engineering Tsinghua University department of Airborne Equipment Army Aviation Institute army aviation Military Delegate Bureau Headquarters of the General Staff

This paper constructs a simulation system of near-field laser imaging for 3D grid model of target,provides some methods for the key problems,such as the modeling of target and laser transceiver,the calculation of laser echo power,the imaging algorithms and so on.A target image library is established by a new imaging method in any rendezvous conditions.The four real-time recognition algorithms which are efficient and suitable for hardware implementation are presented at the conditions of the image incompleteness,intensive noise and arbitrary attitude of target.The experimental results show that all the four algorithms can independently recognize the target effectively and a better recognition effect is obtained by the integration of four algorithms.

关键词：实时目标识别激光成像系统仿真 experimental 近场检测网格模型仿真系统

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An intelligent algorithm for coherent sound source localization based on a strong tracking filter

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Chinese Journal of Aeronautics 2019年第8期32卷 1895-1902页

作者： Jianchao JI Liang WANG Mingxin WANG Song FU School of Aerospace engineering Tsinghua UniversityBeijing 100084China department of Mechanical engineering Army Aviation InstituteBeijing 101123China

Background noise is inevitable when sensor arrays are used for aeroacoustic measurements in wind tunnels. The direct removal of background noise, however, would affect the measurement accuracy. In particular, the existing array signal processing algorithms are either invalid or inefficient for removing the noise that is coherent with the signal of interest. In this paper, an intelligent algorithm is developed to localize the coherent sound sources and background noise in real time by iteratively checking the collected data from the array. The proposed method can automatically adjust the suboptimal fading factor to extract useful information as much as possible in residual sequence. This algorithm is tested in simulations and then demonstrated in an experiment.Compared to the two existing methods, the results indicate that the new method has a good phase-shift tracking ability and rapid estimation-error convergence speed, and can achieve an acceptable performance even for low-cost acoustic sensors. Overall, the proposed method should assist array beamforming and hence benefit aeroacoustic measurement.

关键词： Aeroacoustics Beamforming Coherence Sensor arrays Signal processing

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Determination of delay time in individual transfer function for central aortic pressure reconstruction

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Science China(Life Sciences) 2014年第10期57卷 1034-1038页

作者： YU DanYang XIANG HaiYan LI DeYu WANG YuQi YU MengSun School of Biological Science and Medical engineering Beihang University department of Medical engineering the 201st Hospital of the Chinese Peoples' s Liberation Army department of aviation Medical engineering Institute of Aviation Medicine

In previous research,time-delay(Δt)was a more important parameter than the reflection coefficient in the individual transfer function of central aortic pressure reconstruction.TheΔt can be obtained by electrocardiography(ECG)or phonocardiography(PCG).Because the pre-ejection period remains an uncertain factor,the present study used ECG and PCG to define the delay time and analyzed the accuracy of the reconstruction results.TheΔtpre is the actual delay time derived from the aorta to the carotid pressure wave,ΔtPCG is the time delay between the aortic valve component of the second heart sound and the dicrotic incisura of the carotid pressure wave,andΔtECG represents the delay from the interval of the ECG R-peak to the foot of the carotid pressure wave.Compared with the measured aortic pressure,the reconstruction result obtained byΔt=ΔtPCG slightly differed from the best result estimated byΔt=Δtpre.However,the differences between the result obtained byΔt=ΔtECG and the best result were significant in terms of the diastolic blood pressure,and pulse pressure,and especially in terms of the augmentation index and root-mean-square-error.Thus,theΔt should be determined by PCG for central aortic pressure reconstruction in practice.

关键词：延迟时间传递函数动脉压重构压力波 PCG 颈动脉主动脉

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Performance investigation of intercooler operating in wet condition using distributed parameter model

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航空动力学报 2014年第7期29卷 1598-1605页

作者： ZHOU Ya-feng LIU Gui-lin HAN Ya-hui YANG Chun-xin ZHU Zhi-li School of Energy and Power engineering Beijing University of Aeronautics and Astronautics Shenyang Engine Design and Research institute Aviation Industry Corporation of China School of Aeronautic Science and engineering Beijing University of Aeronautics and Astronautics Mechanical engineering department Army Aviation Institutethe Chinese People's Liberation Army

The performance of a marine gas turbine intercooler operating in wet condition was evaluated.The intercooler was a cross-flow plate-fin heat exchanger that used air and pure water as its working fluids at the hot and cold sides,respectively.The heat transfer performance and the water vapor condensation were investigated for a relative humidity of the inlet air that reached 100% during warship cruise.The condensation of the water vapors increased the hot side outlet temperature by a certain amount,which could in turn influence the performance of the compressor downstream.The condensate film thickness and the void fraction were calculated based on an annular two-phase flow model.It is found that water vapor condensation in hot flow channel increases the outlet temperature with a maximum value of 7.3℃ in the case of 100% relative humidity.The calculated liquid film thickness reaches a maximum value of 4μm,which indicates negligible thermal resistance to heat transfer.The results of liquid film thicknesses also provide a qualitative prediction of the diameter distribution of the condensate water droplets.

关键词： intercooler wet condition plate-fin heat exchanger condensation film thickness

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Minimum Control Energy of Spatial Beam with Assumed Attitude Adjustment Target

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Acta Mechanica Solida Sinica 2020年第1期33卷 51-60页

作者： Weipeng Hu Lingjun Yu Zichen Deng School of Civil engineering and Architecture Xi’an University of TechnologyXi’an 710048China State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of China Xi’an University of TechnologyXi’an 710048China department of aeronautical machinery engineering of army aviation institute Beijing 101123China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China

The dynamic analysis on the ultra-large spatial structure can be simplified drastically by ignoring the flexibility and damping of the structure.However,these simplifications will result in the erroneous estimate on the dynamic behaviors of the ultra-large spatial structure.Taking the spatial beam as an example,the minimum control energy defined by the difference between the initial total energy and the final total energy in the assumed stable attitude state of the beam is investigated by the structure-preserving method proposed in our previous studies in two cases:the spatial beam considering the flexibility as well as the damping effect,and the spatial beam ignoring both the flexibility and the damping effect.In the numerical experiments,the assumed simulation interval of three months is evaluated on whether or not it is long enough for the spatial flexible damping beam to arrive at the assumed stable attitude state.And then,taking the initial attitude angle and the initial attitude angle velocity as the independent variables,respectively,the minimum control energies of the mentioned two cases are investigated in detail.From the numerical results,the following conclusions can be obtained.With the fixed initial attitude angle velocity,the minimum control energy of the spatial flexible damping beam is higher than that of the spatial rigid beam when the initial attitude angle is close to or far away from the stable attitude state.With the fixed initial attitude angle,ignoring the flexibility and the damping effect will underestimate the minimum control energy of the spatial beam.

关键词： Spatial beam Structure-preserving method Generalized multi-symplectic Minimum control energy Hamiltonian

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