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Passive Super-Low Frequency electromagnetic prospecting technique

Frontiers of Earth Science 2017年第2期11卷 248-267页

作者： Nan WANG Shanshan ZHAO Jian HUI Qiming QIN Institute of Remote Sensing and GIS School of Earth and Space Sciences Peking University Beijing 100871 China Key Laboratory of Technology in Geospatial Information Processing and Application System Institute of Electronics Chinese Academy of Sciences Beijing 100190 China

The Super-Low Frequency （SLF） electromag- netic prospecting technique, adopted as a non-imaging remote sensing tool for depth sounding, is systematically proposed for subsurface geological survey. In this paper, we propose and theoretically illustrate natural source magnetic amplitudes as SLF responses for the first step. In order to directly calculate multi-dimensional theoretical SLF responses, modeling algorithms were developed and evaluated using the finite difference method. The theore- tical results of three-dimensional （3-D） models show that the average normalized SLF magnetic amplitude responses were numerically stable and appropriate for practical interpretation. To explore the depth resolution, three-layer models were configured. The modeling results prove that the SLF technique is more sensitive to conductive objective layers than high resistive ones, with the SLF responses of conductive objective layers obviously show- ing uprising amplitudes in the low frequency range. Afterwards, we proposed an improved Frequency-Depth transformation based on Bostick inversion to realize the depth sounding by empirically adjusting two parameters. The SLF technique has already been successfully applied in geothermal exploration and coalbed methane （CBM） reservoir interpretation, which demonstrates that the proposed methodology is effective in revealing low resistive distributions. Furthermore, it siginificantly contributes to reservoir identification with electromagnetic radiation anomaly extraction. Meanwhile, the SLF inter- pretation results are in accordance with dynamic production status of CBM reservoirs, which means it could provide an economical, convenient and promising method for exploring and monitoring subsurface geo-objects.

关键词： Super-Low Frequency （SLF） three-dimen-sional modeling frequency-depth transformation geother-mal exploration coalbed methane （CBM） electromagneticradiation （EMR）

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Mechanism Design and Kinematics Analysis of an Original Cable-driving Exoskeleton robot

Mechanism Design and Kinematics Analysis of an Original Cabl...

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IEEE Advanced Information Management, Communicates, Electronic and Automation Control Conference

作者： Ruqi Ma Zixin Tang Xiangyu Gao Wencheng Ni Beijing Key Laboratory of Intelligent Space Robotic System Technology and Application Institute of Spacecraft System Engineering. CAST Beijing China

To meet the lightweight and flexibility actual requirements of the exoskeleton robot system used for robot assisted rehabilitation;a exoskeleton system according with the motion characteristics of human upper limbs was designed based on the analysis of upper limbs structures. The shoulder and elbow joints of the exoskeleton system are driven by steel wire to realize the movement and torque transfer, which can not only realize the lightweight mechanism design of the exoskeleton by allocating the joint driving components at the robot base, but also can realize the flexible mechanism design of the joints by adjusting the stiffness of the cable-driving system. The decoupling matrix of the exoskeleton cable-driving system was given based on the analysis of the shoulder and elbow joints motion characteristic and the position and pose decoupled kinematics modal was established by using vector product method. The test experiments based on the physical prototype show that the motion range and the motion characteristics of the exoskeleton robot system can perfectly meet the needs of upper limb rehabilitation training.

关键词： Exoskeleton robot Mechanism design Cable-driving Kinematic analysis

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Optimization Design of Bracket and Thermal Controller Structures Based on Lattice Sandwich Cells

Optimization Design of Bracket and Thermal Controller Struct...

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第三届中国国际复合材料科技大会

作者： Xiaoyu Zhang Hao Zhou Huizhong Zeng Yaobing Wang Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering CAST

Structures with minimum weight is highly desired by spacecraft designers. Lattice sandwich cells with advantage of lightweight, multi-function and high stiffness provide wide application potential in spacecraft engineering. For a long time, the applications of lattice sandwich structures in spacecraft are limited due to the difficulties in manufacturing technique. In the past decade, the development of additive manufacturing techniques make the high-precision lattice structures become reality. In present work, the design of the thermal controller structure based on lattice cells and the bracket structures based on lattice cells are achieved using macroscale topology optimization, microscale lattice substitution and design of connection region. All the structures are necessary in spacecraft engineering. They play the role of thermal control and mechanical support of various equipments. All the structures are manufactured with AlSi10Mg by direct metal laser melting. The weight of structures made of lattice cells is much lighter than traditional structures made of solid materials or honey comb plates. The weight reduction are extremely important for the achievement of the spacecraft system engineering. The 3D printed structure can reduce the risk of leakage of phase change materials inside thermal controller because of absence of welding joint.

关键词： Bracket Thermal Controller Lattice Sandwich

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Additive Manufacturing spacecraft Structure Made of Lattice Sandwichs

Additive Manufacturing Spacecraft Structure Made of Lattice ...

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第三届中国国际复合材料科技大会

作者： Hao Zhou Xiaoyu Zhang Fuming Zeng Wenhua Shi Huizhong Zeng Yaobing Wang Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering CAST

Lattice sandwich structures have great advantage in lightweight, multi-function and high stiffness, which provide wide application potential in spacecraft engineering. However, the report of applications of lattice sandwich structures in spacecraft mainstructure is not available due to the difficulties in the manufacturing dimensional precision and the complex connection between parts. In recent years, the development of additive manufacturing techniques, such as selective laser melting, make the high-precision lattice structures become reality. In this work, the design of the first additive manufacturing satellite structure based on lattice cells are achieved using macroscale topology optimization, microscale lattice substitution and design of connection region. The structure is manufactured with AlSi10Mg by direct metal laser melting. The dimensions of the satellite structure are 400×400×400 mm. The main structure plays the role of mechanical support of various equipments. The weight of structures made of lattice cells is much lighter than traditional structures made of solid materials or honey comb plates. The mass of the structure and its carrying capacity are 8 kg and 104 kg, respectively. The structure mass-tosatellite mass ratio is 7.7%, which is lighter than most traditional satellite made of honeycomb sandwich panels, about 15～25%. The weight reduction is extremely important for the achievement of the spacecraft system engineering. The vibration test verified that the satellite structure could endure the vibration loads resulted from the rocket launching.

关键词： spacecraft Structure Lattice Sandwich Selective Laser Melting

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Virtual Constraint Based Adaptive Control for Biped robot with Speed Regulation

Virtual Constraint Based Adaptive Control for Biped Robot wi...

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IEEE International Conference on Mechatronics and Automation

作者： Jianfei Li Yaobing Wang Dawei Zhang Li Liu Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing China Center of Excellence for Intelligent Mechanical Systems College of Engineering Peking University Beijing China

ISBN: (纸本)9781509023974

The Virtual Holonomic Constraint (VHC) approach, with its flexibility and stability, is drawing more attentions in generating gait for biped robots. This paper generalizes the VHC approach by adding other variables such as walking speed to the constraint functions. The robot is able to walk up or down along slopes with commanded speeds, and more importantly, allows it to walk continuously and steadily in varying surfaces. In addition, the control approach named Partial Decoupling Control is used to implement the VHC, which at the first time equips the VHC approach with the parameter adaptation laws which significantly improves the stability and performance of the systems. Full dynamics simulations with a five-bar planar robot are used to illustrate the effectiveness of the proposed approach.

关键词： adaptive control virtual constraints VHC biped robot speed regulation

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Research of Visual Servo Control system for space intelligent robot

Research of Visual Servo Control System for Space Intelligen...

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2015 IEEE Advanced Information technology,Electronic and Automation Control Conference(IAEAC 2015)

作者： Liang Changchun Zhang Xiaodong Pan Dong Liu Xin Beijing Key Laboratory of Intelligent Space Robotic System Technology and Applications Beijing Institute of Spacecraft System Engineering CAST

ISBN: (纸本)9781479919819

space intelligent robotic systems are expected to play an increasingly important role in the *** robotic onorbital service,whose key is the tracking and capturing technology,becomes research hot in recent *** this paper,the authors propose a vision servo control system for target *** manipulator will be an intelligent robotic system with large-scale movement,functional agility,and autonomous ability,and it can be operated by astronauts in the space station or be controlled by the ground operator in the remote operation *** realize the autonomous movement and capture mission of SRM,a kind of autonomous programming strategy based on multi-camera vision fusion is designed and the selection principle of object visual position and orientation measurement information is defined for the better *** control system hierarchy is designed and reliability is considering to guarantee the abilities of control *** last,a ground experiment system is set up based on the concept of robotic control *** that,the autonomous target capturing experiments are *** experiment results validate the proposed algorithm,and demonstrates that the control system can fulfill the needs of function,real-time and reliability.

关键词： Control system On-orbital service space robot Vision servo

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Corrigendum to “Retrieving forest canopy clumping index using terrestrial laser scanning data” [Remote Sens. Environ. 210 (2018) 452–472]

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Remote Sensing of Environment 2018年 211卷 472-472页

作者： Lixia Ma Guang Zheng Xiaofei Wang Shiming Li Yi Lin Weimin Ju International Institute for Earth System Science Nanjing University Nanjing 210023 China Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology and Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023 China Collaborative Innovation Center of South China Sea Studies Nanjing University Nanjing 210023 China Institute of Forest Resource and Information Techniques Chinese Academy of Forestry Beijing 100091 China School of Earth and Space Sciences Peking University Beijing 100871 China

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Research of integration simulation system of space dual-arm robot

Research of integration simulation system of space dual-arm ...

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IEEE International Conference on robotics and Biomimetics, IEEE-ROBIO 2015

作者： Xiaodong, Zhang Yafang, Liu Yaobing, Wang Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Institute of Spacecraft System Engineering CAST Beijing China

ISBN: (纸本)9781467396745

A set of integrated simulation system of space dual-arm robot is developed in the paper. Based on modular design concept, the system is composed of the communication module, task scheduling management module, path planning module, dynamic control module, 3D geometric model and collision detection module and the system uses C programming language and Visual Studio 2010 to realize the key algorithm while the entity model and the simulation scenarios are created by OSG (Open Scene Graph). Compared with other simulation methods, this method is stronger in visualization and post-processing, which can also realize closed-loop control of the key algorithm. Finally, the application simulations are implemented to verify the algorithms of coordinated space dual-arm robot by using this system. The results show the effectiveness of the system and verify the feasibility of mission planning. © 2015 IEEE.

关键词： Motion planning

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A sub-pixel SAR and optical image registration method 66

A sub-pixel SAR and optical image registration method

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66th International Astronautical Congress 2015: space - The Gateway for Mankind's Future, IAC 2015

作者： Zhang, Hanmo Lu, Shan You, Hongjian Shanghai Key Laboratory of Aerospace Intelligent Control Technology Shanghai Aerospace Control Technology Institution China Key Laboratory of Geo-Spatial Information Processing and Application System Technology Institute of Electronics Chinese Academy of Sciences Beijing China

ISBN: (纸本)9781510818934

Automatic image registration method is important because data amount acquired and processed is increasingly heavy. For SAR and optical sensor images, it is important to align the same object shown in different images from multi sensors. Considering extracting and matching features in SAR and optical images, a template registration strategy is proposed in this paper. A particular similarity measurement which is robust in matching remote sensing images of general sceneries is hardly to construct. Being the invertible and essential tendency nowadays in the field of earth observation, high pixel-resolution images can offer much more information of the ground. Thus subpixel image registration methods have been researched, among which can successfully achieve 1/50 pixel level accuracy in matching homologous sensor image. This paper firstly investigated the performance of 2D Gaussian fitting for low correlated synthetic images and real satellite images acquired by Radat SAT-2, COSMO and TerraSAR-X satellites. Three algorithms for subpixel locating have been utilized with consideration of the low correlated coefficient peak and corrupted shape of neighbourhood around it. The results show 2D Gaussian fitting is the most efficient on noisy coefficient maps. Then a subpixel image registration method for SAR and optical images is proposed. Normalized gradient correlation (NGC) algorithm is used to solve the problem of different intensity property at first, and by combining 2D Gaussian fitting to relocate matched points at a subpixel level accuracy. Experiment results have shown that the proposed method has enough capabilities in handling differences between images from multi-sensors. The proposed approach has been found to be simple and efficient in implementation with a low computation load. And the most important performance is the results presented here have achieved matching accuracy within 1 pixel.

关键词： Image registration

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A modified wind vector retrieval algorithm for polarimetric scatterometer

A modified wind vector retrieval algorithm for polarimetric ...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Xuetong Xie Mingsen Lin Zhou Huang Juhong Zou Dongxuan Tian Lixia Liu Xiaoning Wang Shiwei Dong ATR State Key Laboratory National University of Defense Technology Changsha China National Satellite Ocean Application Service Beijing China Institute of Remote Sensing and Geographic Information System Peking University Beijing China Institute of Space Radio Technology National Key Laboratory of Space Microwave Technology Xi'an China

Experiments and theoretical analysis demonstrate that the polarimetric scatterometer has the potential in enhancing the accuracy of the wind vector retrieval. However, currently, there is no special wind vector retrieval algorithm for the polarimetric scatterometer. Based on the distribution characteristic of the objective function, a modified wind vector retrieval algorithm was designed for the conically scanning polarimetric scatterometer in this paper. Simulation experiments indicated that this algorithm could further improve the retrieval precision of the polarimetric scatterometer in comparison with the traditional algorithm, especially in the nadir- and outer-swath. By extending the wind direction range for the first and second ambiguity in the nadir- and outer-swath, the algorithm can effectively reduce the uncertainty of the wind direction solutions with error magnitude of 0° to 15°. Up to 2° improvement in wind direction retrieval can be achieved in the nadir track.

关键词： Radar measurements spaceborne radar Wind speed Algorithm design and analysis Oceans Filtering algorithms Accuracy

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