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Spatio-temporal decision-making and trajectory planning framework with flexible constraints in closed-loop dynamic traffic

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IET intelligent Transport Systems 2023年第4期17卷 704-715页

作者： Zhang, Ting Fu, Mengyin Liu, Tong Song, Wenjie State Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing Institute of Technology Beijing China Nanjing University of Science and Technology Nanjing China

Driving in interactive dynamic traffic is a huge challenge for autonomous vehicles, especially for motion planning. The autonomous vehicle not only needs to predict the future states of the social vehicles to avoid a collision but also realizes the comfort and continuous plan. To deal with the problem, a spatio-temporal decision-making and motion planning framework with flexible constraints based on previous work is proposed. Improvements can be highlighted in three aspects. First, a neural network for trajectory prediction is trained and it is integrated into the framework, which can learn the social vehicles' reactions in the negotiation better and give more accurate predictions. Second, instead of setting the fixed local targets, the flexible-constraint mechanism is introduced to increase the success rate of continuous planning, specifically, the local planning target is determined conditioned on the situation with an elastic factor. Third, two popular simulators with randomly disposed traffic participants are exploited, where vehicles are mutually influenced, more similar to real-world traffic. The closed-loop tests with zero crashes and the comparative experiments with traditional models demonstrate the superior performance and practical significance of the proposed framework. © 2022 The Authors. IET intelligent Transport Systems published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and technology.

关键词： Autonomous vehicles

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Simulation of Nanosecond Microwave Pulse Amplification Based on a Gyrotron Traveling Wave Tube

Simulation of Nanosecond Microwave Pulse Amplification Based...

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2024 Photonics and Electromagnetics Research Symposium, PIERS 2024

作者： Pan, Ruoyang Zhang, Zhiyuan Liu, Guo Wang, Weijie Yao, Yelei Jiang, Wei Wu, Zewei Pu, Youlei Wang, Jianxun Luo, Yong University of Electronic Science and Technology of China School of Electronic Science and Engineering Chengdu China Laboratory of Electromagnetic Space Cognition and Intelligent Control Beijing China

ISBN: (纸本)9798350375909

The paper presents the simulation results for nanosecond pulse amplification utilizing a TE11 mode Ku-band gyrotron traveling wave tube (gyro-TWT). This study evaluates the output performance across various input pulse widths within the 15-17 GHz frequency range. Simulations show that the minimum output pulse width is 0.8 ns, with an output power of 183.9 kW. Moreover, when input pulse widths exceed 2 ns, it is observed that the tube can attain a saturated output power of 293.1 kW, with negligible disparity between input and output pulse widths. The gyro-TWT can serve as a nanosecond pulse source, with potential applications in fields such as military radar, biomedicine, and microwave chemistry. © 2024 IEEE.

关键词： Military radar

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Broadband and High-Power Sub-terahertz Gyro-TWTs and Ultrashort Electromagnetic Pulse Generation 5th

Broadband and High-Power Sub-terahertz Gyro-TWTs and Ultrash...

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5th China and International Young Scientist Terahertz Conference, YTHZ 2024

作者： Liu, Guo Jiang, Wei Yao, Yelei Wang, Weijie Cao, Yingjian Wang, Yu Wu, Zewei Pu, Youlei Wang, Jianxun Luo, Yong University of Electronic Science and Technology of China Chengdu611731 China Laboratory of Electromagnetic Space Cognition and Intelligent Control Beijing100089 China

ISBN: (纸本)9789819739127

In this paper, a short demonstration about the recent progress of our high-power broadband gyrotron travelling wave tube (gyro-TWT) amplifiers in the sub-terahertz band (W and G-band) are respectively reported. Hot test of the W- and G-band gyro-TWTs had respectively achieved a pulsed/averaged output power of over 120 kW/20 kW and 35 kW/2.1 kW within a 10 GHz bandwidth. Based on the fabricated sub-terahertz gyro-TWTs, a scheme to generate high power, ultrashort electromagnetic pulses based on the chirped signal compressor is also presented, which had been verified in the micro- and millimeter wave band. The presented sub-terahertz high-power sources and ultrashort pulses have potential applications in the high-resolution imaging radar, deep space communication, bio-medicine, material modification and catalysis, etc. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Gyroscopes

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Elastic wave propagation and attenuation characteristics of roof fracture source

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Geomechanics and Engineering 2025年第4期40卷 295-305页

作者： Zhang, Peng-Fei Zhao, Tong-Bin Gong, Xu-Fei Tan, Yan Guo, Chuan-Qing College of Energy and Mining Engineering Shandong University of Science and Technology Qingdao266590 China State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology Shandong University of Science and Technology Qingdao266590 China Shandong Key Laboratory of Intelligent Prevention and Control of Dynamic Disaster in Deep Mines Shandong University of Science and Technology Qingdao266590 China Energy Group Co. Ltd. Jining No.2 Coal Mine Jining272012 China

Abstract. The propagation attenuation law of elastic waves generated by rock mass fractures in strata is of great significance in explaining engineering problems, such as rock bursts. In this study, a wave velocity model was established based on the actual stratum conditions of the Jining No.2 coal mine in China. The propagation process of different types of elastic waves is simulated using the elastic wave equation and finite difference method. The attenuation coefficients of various elastic wave parameters propagating at different positions were calculated. Based on the calculated results, an attenuation equation for the elastic wave energy is proposed. The results show that the propagation of S-waves and P-waves in strata is similar to each other, and wave pattern transformation occurs at the interface of the strata. The magmatic rocks played a role in channeling and reflecting elastic wave propagation, leading to the occurrence of low-energy aftershocks in the coal seams. The peak displacement, peak stress, and energy density of the elastic wave that propagated to the coal seam after the siltstone layer fracture of the roof of the 3down coal seam decreased to 28%, 25%, and 9% of the source, respectively. The attenuation of elastic wave energy is highly correlated with the propagation distance, and the attenuation equation can be represented as an exponential function. These results are of great significance for revealing the propagation attenuation process of elastic waves in the stratum. © 2025 Techno-Press, Ltd.

关键词： Exponential functions

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Q-Learning-Based Target Selection for Bearings-Only Autonomous Navigation

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Journal of Systems science & Complexity 2021年第4期34卷 1401-1425页

作者： XIONG Kai WEI Chunling Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100094China

This paper presents a Q-learning-based target selection algorithm for spacecraft autonomous navigation using bearing observations of known visible *** the considered navigation system,the position and velocity of the spacecraft are estimated using an extended Kalman filter(EKF)with the measurements of inter-satellite line-of-sight(LOS)vectors obtained via an onboard star *** paper focuses on the selection of the appropriate target at each observation period for the star camera adaptively,such that the performance of the EKF is *** derive an effective algorithm,a Q-function is designed to select a proper observation region,while a U-function is introduced to rank the targets in the selected *** the Q-function and the U-function are constructed based on the sequence of innovations obtained from the *** efficiency of the Q-learning-based target selection algorithm is illustrated via numerical simulations,which show that the presented algorithm outperforms the traditional target selection strategy based on a Cramer-Rao bound(CRB)in the case that the prior knowledge about the target location is inaccurate.

关键词： Bearings-only autonomous navigation convergence analysis extended Kalman filtering Q-Learning target selection

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Data-Driven control of Distributed Event-Triggered Network Systems

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IEEE/CAA Journal of Automatica Sinica 2023年第2期10卷 351-364页

作者： Xin Wang Jian Sun Gang Wang Frank Allgower Jie Chen the National Key Laboratory of Autonomous Intelligent Unmanned Systems School of AutomationBeijing Institute of TechnologyBeijing 100081 the Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China IEEE the Institute for Systems Theory and Automatic Control University of StuttgartStuttgart 70550Germany the Department of Control Science and Engineering Tongji UniversityShanghai 201804 the National Key Laboratory of Autonomous Intelligent Unmanned Systems Beijing Institute of TechnologyBeijing 100081China

The present paper deals with data-driven event-triggered control of a class of unknown discrete-time interconnected systems(*** systems).To this end,we start by putting forth a novel distributed event-triggering transmission strategy based on periodic sampling,under which a model-based stability criterion for the closed-loop network system is derived,by leveraging a discrete-time looped-functional *** the model-based criterion with a data-driven system representation recently developed in the literature,a purely data-driven stability criterion expressed in the form of linear matrix inequalities(LMIs)is ***,the data-driven stability criterion suggests a means for co-designing the event-triggering coefficient matrix and the feedback control gain matrix using only some offline collected state-input ***,numerical results corroborate the efficacy of the proposed distributed data-driven event-triggered network system(ETS)in cutting off data transmissions and the co-design procedure.

关键词： Data-driven control distributed event-triggered network system(ETS) linear matrix inequalitie(LMI) looped-functional stability

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Multi-Level Robotic Pouring Using Offline Reinforcement Learning

Multi-Level Robotic Pouring Using Offline Reinforcement Lear...

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2024 IEEE International Conference on Robotics and Biomimetics, ROBIO 2024

作者： Zhang, Xiaoxiong Liu, Junwei Zhang, Wei School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen Key Laboratory of Control Theory and Intelligent Systems Shenzhen518055 China

ISBN: (纸本)9781665481090

This paper presents a novel learning-based method for a robotic manipulator to achieve liquid pouring across different liquid levels using only visual sensors. Previous works have relied on either online reinforcement learning or imitation learning, which are limited by sim-to-real gaps or data efficiency. In this paper, we propose to combine supervised learning and offline reinforcement learning, utilizing a human demonstration dataset containing only successful pouring at the highest level. Specifically, our approach employs supervised learning for a visual classifier, transforming the visual input into a categorical distribution over liquid levels. The offline reinforcement learning method is applied to a binary-conditioned control policy, which takes a binary signal and the robot's proprioception as inputs to determine the action. The binary signal indicates whether the desired liquid level has been reached based on the target liquid level. Through experiments, our method demonstrates superior effectiveness compared to a state-of-the-art imitation learning algorithm. Moreover, tests in unseen scenarios and multiple liquid level commands verify the generalization and transferability of our approach. © 2024 IEEE.

关键词： Self-supervised learning

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Ground-based investigations on phase-moving phenomenon with space sublimation cooling for lunar exploration missions

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Chinese Journal of Aeronautics 2022年第8期35卷 65-74页

作者： Enhui LI Yunze LI Jixiang WANG Man YUAN Jingyan XIE Yuehang SUN Lizhu YANG Xianwen NING School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China Beijing Key Laboratory of Space Thermal Control Technology China Academy of Space TechnologyBeijing 100094China

The lunar surface is a typical vacuum environment,and its harsh heat rejection conditions bring great challenges to the thermal control technology of the exploration *** addition to the radiator,the sublimator is recommended as one of the promising options for heat *** sublimator makes use of water to freeze and sublimate in a porous medium,rejecting heat to the vacuum *** complex heat and mass transfer process involves many physical phenomena such as the freezing and sublimation phase change of water in the porous medium and the movement of the phase-change *** this paper,the visualized ground-based experimental approaches of space sublimation cooling were presented to reveal the moving law of threephase point and the growth phenomenon of ice-peak and icicle in microchannels under vacuum *** visualized experiments and results prove that the freezing ice is divided into the porous ice-peak and the transparent *** the sublimation progresses,the phase-change interface moves downward steadily,the length of the ice-peak increases,but the icicle *** visualized experiments of space sublimation cooling in the capillary have guiding significance to reveal the sublimation cooling mechanism of water in the sublimator for lunar exploration missions.

关键词： Lunar vacuum environment Phase-change flow space sublimation cooling Unsteady phase-moving phenomenon Visualized ground-based experimental approaches

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System Design for Pose Determination of spacecraft Using Timeof-Flight Sensors

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space(science & technology) 2022年第1期2022卷 46-63页

作者： Wenshan Zhu Jinzhen Mu Changbao Shao Jiaqian Hu Beichao Wang Zhongkai Wen Fei Han Shuang Li Advanced Space Technology Laboratory College of AstronauticsNanjing University of Aeronautics and AstronauticsNanjing 211106China Shanghai Key Laboratory of Space Intelligent Control Technology Shanghai 201109China

The pose determination between nanosatellites and the cooperative spacecraft is essential for swarm in-orbit ***–flight(ToF)sensors are one of the most promising sensors to achieve the *** paper presented an end-to-end assessment of how these sensors were used for pose ***,an embedded system was designed based on the ToF camera with lasers as a driven light *** and depth images were collected to detect and match the cooperative spacecraft in real time,obtaining the pose information.A threshold-based segmentation was proposed to find a small set of the pixels belonging to reflector *** operating on the defined active pixel set reduced computational ***,morphological detection combined with an edge following-based ellipse detection extracted the centroid coordinate of the circular marker,while the center-of-heart rate was calculated as the recognition ***,the marker matching was completed using a deterministic annealing algorithm,obtaining two sets of 3D coordinates.A singular value decomposition(SVD)algorithm estimated the relative pose between the nanosatellite and the *** the experiments,the pose calculated by the TOF camera reached an accuracy of 0.13 degrees and 2 *** accurately identified the markers and determined the pose,verifying the feasibility of the ToF camera for rendezvous and docking.

关键词： estimation coordinate circular

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Two performance indicators of reaction wheel underactuated configuration 1

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19th Chinese intelligent Systems Conference, CISC 2023

作者： Xie, Jun Feng, Jia-Jia Zhang, Yu-Jie Chen, Qiang Beijing Institute of Control Engineering Beijing100190 China Science and Technology on Space Intelligent Control Laboratory Beijing100190 China

ISBN: (数字)9789819968824

ISBN: (纸本)9789819968817

It is of great engineering significance to study the underactuated configuration of reaction wheels. Aiming at the problem of how to effectively improve the control performance of the control system, this paper proposes two performance optimization indicators in the reaction wheel underactuated configuration from the control mechanism of the underactuated control, which provides a reference for the optimization design of the reaction wheel underactuated configuration. The two performance indicators are the area of the actuated Euler axis and the error angle of the underactuated axis. The simulation analysis of the performance indicators is carried out for an engineering example. The results show that the optimization of the two performance indicators proposed in this paper can effectively improve the control performance of the system under underactuated control. It is proved that the two performance optimization indicators proposed in this paper are feasible and effective, and have certain engineering application value. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023

关键词： Benchmarking

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