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Three-dimensional Construction and Omni-directional Rolling Analysis of a Novel Frame-like Lattice Modular Robot 被引量:4
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作者 DING Wan WU Jianxu YAO Yan'an 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第4期691-701,共11页
Lattice modular robots possess diversity actuation methods, such as electric telescopic rod, gear rack, magnet, robot arm, etc. The researches on lattice modular robots mainly focus on their hardware descriptions and ... Lattice modular robots possess diversity actuation methods, such as electric telescopic rod, gear rack, magnet, robot arm, etc. The researches on lattice modular robots mainly focus on their hardware descriptions and reconfiguration algorithms. Meanwhile, their design architectures and actuation methods perform slow telescopic and moving speeds, relative low actuation force verse weight ratio, and without internal space to carry objects. To improve the mechanical performance and reveal the locomotion and reconfiguration binary essences of the lattice modular robots, a novel cube-shaped, frame-like, pneumatic-based reconfigurable robot module called pneumatic expandable cube(PE-Cube) is proposed. The three-dimensional(3D) expanding construction and omni-directional rolling analysis of the constructed robots are the main focuses. The PE-Cube with three degrees of freedom(Do Fs) is assembled by replacing the twelve edges of a cube with pneumatic cylinders. The proposed symmetric construction condition makes the constructed robots possess the same properties in each supporting state, and a binary control strategy cooperated with binary actuator(pneumatic cylinder) is directly adopted to control the PE-Cube. Taking an eight PE-Cube modules' construction as example, its dynamic rolling simulation, static rolling condition, and turning gait are illustrated and discussed. To testify telescopic synchronization, respond speed, locomotion feasibility, and repeatability and reliability of hardware system, an experimental pneumatic-based robotic system is built and the rolling and turning experiments of the eight PE-Cube modules' construction are carried out. As an extension, the locomotion feasibility of a thirty-two PE-Cube modules' construction is analyzed and proved, including dynamic rolling simulation, static rolling condition, and dynamic analysis in free tipping process. The proposed PE-Cube module, construction method, and locomotion analysis enrich the family of the lattice modular robot and provide the instruction to design the lattice modular robot. 展开更多
关键词 modular robot pneumatic expandable cube pneumatic actuation omni-directional rolling binary control strategy
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Global Inverse Optimal Tracking Control of Underactuated Omni-directional Intelligent Navigators (ODINs) 被引量:2
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作者 Khac Duc Do 《Journal of Marine Science and Application》 CSCD 2015年第1期1-13,共13页
This paper presents a design of optimal controllers with respect to a meaningful cost function to force an underactuated omni-directional intelligent navigator (ODIN) under unknown constant environmental loads to tr... This paper presents a design of optimal controllers with respect to a meaningful cost function to force an underactuated omni-directional intelligent navigator (ODIN) under unknown constant environmental loads to track a reference trajectory in two-dimensional space. Motivated by the vehicle's steering practice, the yaw angle regarded as a virtual control plus the surge thrust force are used to force the position of the vehicle to globally track its reference trajectory. The control design is based on several recent results developed for inverse optimal control and stability analysis of nonlinear systems, a new design of bounded disturbance observers, and backstepping and Lyapunov's direct methods. Both state- and output-feedback control designs are addressed. Simulations are included to illustrate the effectiveness of the proposed results. 展开更多
关键词 inverse optimality optimal controller global tracking underactuated omni-directional intelligent navigator (ODIN) Lyapunov's direct method backstepping method
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AlGaInP thin-film LED with omni-directionally reflector and ITO transparent conducting n-type contact
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作者 张剑铭 邹德恕 +6 位作者 徐晨 郭伟玲 朱彦旭 梁庭 达小丽 李建军 沈光地 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第11期3498-3501,共4页
In this paper a novel A1GalnP thin-film light-emitting diode (LED) with omni-directionally reflector (ODR) and transparent conducting indium tin oxide (ITO) n-type contact structure is proposed, and fabrication ... In this paper a novel A1GalnP thin-film light-emitting diode (LED) with omni-directionally reflector (ODR) and transparent conducting indium tin oxide (ITO) n-type contact structure is proposed, and fabrication process is developed. This reflector is realized with the combination of a low-refractive-index dielectric layer and a high reflectivity metal layer. This allows the light emitted or internally reflected downwardly towards the GaAs substrate at any angle of incidence to be reflected towards the top surface of the chip. ITO n-type contact is used for anti-reflection and current spreading layers on the ODR-LED with ITO. The sheet resistance of the ITO films (95 nm) deposited on n- ohmic contact of ODR-LED is of the order 23.5Ω/△ with up to 90% transmittance (above 92% for 590-770 nm) in the visible region of the spectrum. The optical and electrical characteristics of the ODR-LED with ITO are presented and compared to conventional AS-LED and ODR-LED without ITO. It is shown that the light output from the ODR-LED with ITO at forward current 20mA exceeds that of AS-LED and ODR-LED without ITO by about a factor of 1.63 and 0.16, respectively. A favourable luminous intensity of 218.3 mcd from the ODR-LED with ITO (peak wavelength 620 nm) could be obtained under 20 mA injection, which is 2.63 times and 1.21 times higher than that of AS-LED and ODR-LED without ITO, respectively. 展开更多
关键词 ALGAINP thin-film LED omni-directional reflector ITO
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A New Compact Omni-Directional Quasi-Self-Complementary Antenna for Wireless Communication Systems
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作者 Aliakbar Dastranj 《Open Journal of Antennas and Propagation》 2016年第2期24-33,共10页
This article describes a new miniaturized omni-directional antenna with quasi-self-complementary structure for wireless communication applications. A novel ground structure composed of five rectangular plates is propo... This article describes a new miniaturized omni-directional antenna with quasi-self-complementary structure for wireless communication applications. A novel ground structure composed of five rectangular plates is proposed to enhance the impedance bandwidth and reduce the antenna size. The proposed antenna is comprised of two patches surrounded by the ground structure. Two metal patches of the antenna are located on two opposite sides of the dielectric substrate. The feed patch is used to excite the radiation patch. This unique design is realized by properly choosing the suitable feed patch shape, selecting similar slot shape on the radiation patch, and tuning their dimensions. The proposed antenna with an extremely small size of 6 mm × 9 mm has an operating impedance bandwidth ranging from 4.5 to 6.1 GHz for S<sub>11</sub> < -10 dB, which also covers the two IEEE 802.11a wireless local area network bands (5.15 - 5.35 GHz and 5.725 - 5.825 GHz). In addition to be very small in size, the antenna exhibits omni-directional radiation patterns in the entire operating bandwidth and low cross polarization. The distortionless time domain performance of the antenna is confirmed by investigation of the phase response and group delay. The obtained results in both frequency and time domain show that the proposed antenna is suitable for use in wireless communication systems. 展开更多
关键词 Ground Structure omni-directionAL Quasi-Self-Complementary Antenna QSCA Wireless Communication Systems WLAN
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Omni-directional mirror for visible light based on one-dimensional photonic crystal 被引量:2
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作者 关慧欢 韩培德 +3 位作者 杨艳青 李玉平 张雪 张文婷 《Chinese Optics Letters》 SCIE EI CAS CSCD 2011年第7期72-75,共4页
The omni-directional reflection characteristics of one-dimensional photonic crystals composed of Ta2O5/MgF2 multi-quantum well (MQW) are studied using the transfer matrix method. An omnidirectional reflector consist... The omni-directional reflection characteristics of one-dimensional photonic crystals composed of Ta2O5/MgF2 multi-quantum well (MQW) are studied using the transfer matrix method. An omnidirectional reflector consisting of three and four Ta2O5/MgF2 MQWs is investigated. Results show that the photonic band gap of the photonic crystal composed of three and four Ta2O5/MgF2 MQWs, which are within the wavelength ranges of 402-712 and 412-1,023 nm, respectively, could cover the entire visible region. The relationship among the width of the band gap, its location, reflectivity rate, and incident angle of the incident light is analyzed. The optimal structural parameters of the MQW of the omni-directional reflector in the visible region are also calculated. The calculations provide a guide for the design of omni- directional reflection devices in the visible region. 展开更多
关键词 omni-directional mirror for visible light based on one-dimensional photonic crystal MQW PBG Ta nm mode FIGURE
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Development of an Omni-Directional Shear Horizontal Wave Transducer Based on a Radially Poled Piezoelec trie Ring
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作者 Qiang Huan Mingtong Chen +1 位作者 Ai-Kah Soh Faxin Li 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2019年第1期29-39,共11页
For the inspection of large plate-like structures,the omni-directional guided wave transducer-based system has been regarded as an effective tool since only a few transducers are required to cover the entire inspectio... For the inspection of large plate-like structures,the omni-directional guided wave transducer-based system has been regarded as an effective tool since only a few transducers are required to cover the entire inspection area without blind zones.In comparison with Lamb waves,the shear horizontal(SH)wave is more promising because its fundamental mode is non-dispersive.In this work,we proposed an omni-directional SH wave piezoelec trie t ransducer(OSH-PT)based on a radially poled d24-mode PZT ring.Eoth the finite element simulations and experiments were carried out to demonstrate its performance in generating and receiving SH°wave.Results showed that the radially poled OSH-PT could generate single-mode SHo wave and receive SHo wave only over a wide frequency range from 70 to 200 kHz.The obtained signal-to-noise ratio can reach up to 26 dB in generation and 24 dB in reception.The omni-directivity of this OSH-PT is also very good with the deviation only about 6%in both generation and reception of SHo wave.Considering its easy fabrication,low cost and superior performances,this proposed OSH-PT may promote the applications of SHo wave-based inspection in structural health monitoring and nondestructive testing. 展开更多
关键词 omni-directionAL Guided WAVE SHEAR HORIZONTAL WAVE Piezoelec TRIE t ransducer
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Experimental investigation of omnidirectional multiphysics bilayer invisibility cloak with anisotropic geometry
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作者 丰火雷 张兴伟 +2 位作者 周利敏 张悦凯 倪玉山 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期649-658,共10页
Thermal-electric bilayer invisibility cloak can prevent the heat flux and electric current from touching the object without distorting the external temperature and electric potential fields simultaneously.In this pape... Thermal-electric bilayer invisibility cloak can prevent the heat flux and electric current from touching the object without distorting the external temperature and electric potential fields simultaneously.In this paper,we design an omnidirectional thermal-electric invisibility cloak with anisotropic geometry.Based on the theory of neutral inclusion,the anisotropic effective thermal and electric conductivities of confocal elliptical bilayer core-shell structure are derived,thus obtaining the anisotropic matrix material to eliminate the external disturbances omnidirectionally.The inner shell of the cloak is selected as an insulating material to shield the heat flux and electric current.Then,the omnidirectional thermal-electric cloaking effect is verified numerically and experimentally based on the theoretical anisotropic matrix and manufactured composite structure,respectively.Furthermore,we achieve the thermal-electric cloaking effect under a specific direction of heat flux and electric current using the isotropic natural materials to broaden the selection range of materials.The method proposed to eliminate anisotropy and achieve the omnidirectional effect could also be expanded to other different physical fields for the metadevices with different functions. 展开更多
关键词 omni-directionality MULTIPHYSICS bilayer confocal ellipse invisibility cloak
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V-Shaped Monopole Antenna with Chichena Itzia Inspired Defected Ground Structure for UWB Applications 被引量:7
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作者 Naeem Ahmad Jan Saad Hassan Kiani +4 位作者 Fazal Muhammad Daniyal Ali Sehrai Amjad Iqbal Muhammad Tufail Sunghwan Kim 《Computers, Materials & Continua》 SCIE EI 2020年第10期19-32,共14页
Due to rapid growth in wireless communication technology,higher bandwidth requirement for advance telecommunication systems,capable of operating on two or higher bands with higher channel capacities and minimum distor... Due to rapid growth in wireless communication technology,higher bandwidth requirement for advance telecommunication systems,capable of operating on two or higher bands with higher channel capacities and minimum distortion losses is desired.In this paper,a compact Ultra-Wideband(UWB)V-shaped monopole antenna is presented.UWB response is achieved by modifying the ground plane with Chichen Itzia inspired rectangular staircase shape.The proposed V-shaped is designed by incorporating a rectangle,and an inverted isosceles triangle using FR4 substrate.The size of the antenna is 25 mm×26 mm×1.6 mm.The proposed V-shaped monopole antenna produces bandwidth response of 3 GHz Industrial,Scientific,and Medical(ISM),Worldwide Interoperability for Microwave Access(WiMAX),(IEEE 802.11/HIPERLAN band,5G sub 6 GHz)which with an additional square cut amplified the bandwidth response up to 8 GHz ranging from 3.1 GHz to 10.6 GHz attaining UWB defined by Federal Communications Commission(FCC)with a maximum gain of 3.83 dB.The antenna is designed in Ansys HFSS.Results for key performance parameters of the antenna are presented.The measured results are in good agreement with the simulated results.Due to flat gain,uniform group delay,omni directional radiation pattern characteristics and well-matched impedance,the proposed antenna is suitable for WiMAX,ISM and heterogeneous wireless systems. 展开更多
关键词 V-shape MONOPOLE GAIN STAIRCASE ULTRA-WIDEBAND omni-directionAL defected ground structure
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Monitoring a Wide Manufacture Field Automatically by Multiple Sensors
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作者 LU Jian HAMAJIMA Kyoko JIANG Wei 《自动化学报》 EI CSCD 北大核心 2006年第6期956-967,共12页
This research is dedicated to develop a safety measurement for human-machine cooperative system, in which the machine region and the human region cannot be separated due to the overlap and the movement both from human... This research is dedicated to develop a safety measurement for human-machine cooperative system, in which the machine region and the human region cannot be separated due to the overlap and the movement both from human and from machines. Our proposal here is to automatically monitor the moving objects by image sensing/recognition method, such that the machine system can get enough information about the environment situation and about the production progress at any time, and therefore the machines can accordingly take some corresponding actions automatically to avoid hazard. For this purpose, two types of monitor systems are proposed. The first type is based on the omni directional vision sensor, and the second is based on the stereo vision sensor. Each type may be used alone or together with another type, depending on the safety system's requirements and the specific situation of the manufacture field to be monitored. In this paper, the description about these two types are given, and as for the special application of these image sensors into safety control, the construction of a hierarchy safety system is proposed. 展开更多
关键词 Sensor network robot vision safety control stereo vision omni-direction vision
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Antenna and Anti-antenna
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作者 Michael Bank Benny Milgrom Yuri Shalyt 《Journal of Energy and Power Engineering》 2020年第6期187-192,共6页
One of today’s actual problems in the field of antennas is the possibility of developing a small wideband antenna,which can work without grounding.Absence of these antennas can lead to serious problems for example in... One of today’s actual problems in the field of antennas is the possibility of developing a small wideband antenna,which can work without grounding.Absence of these antennas can lead to serious problems for example in case of designing small transceivers for cellular systems.In this article we show a proposed version of these antennas.Today there do not exist theoretical investigations of connections between electromagnetic fields and currents in flat metallic plates.Therefore,the basis of this work is optimization of proposed antenna construction by simulations. 展开更多
关键词 Wide band TRIANGLE ANTENNA QUARTER wave length omni-directionAL cellular satellite system
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Development of Nanostructured Antireflection Coatings for EO/IR Sensor and Solar Cell Applications
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作者 Ashok K. Sood Adam W. Sood +10 位作者 Roger E. Welser Gopal G. Pethuraja Yash R. Puri Xing Yan David J. Poxson Jaehee Cho E. Fred Schubert Nibir K. Dhar Dennis L. Polla Pradeep Haldar Jennifer L. Harvey 《Materials Sciences and Applications》 2012年第9期633-639,共7页
Electro-optical/infrared (EO/IR) sensors and photovoltaic power sources are being developed for a variety of defense and commercial applications. One of the critical technologies that will enhance both EO/IR sensor an... Electro-optical/infrared (EO/IR) sensors and photovoltaic power sources are being developed for a variety of defense and commercial applications. One of the critical technologies that will enhance both EO/IR sensor and photovoltaic module performance is the development of high quality nanostructure-based antireflection coatings. In this paper, we review our work on advanced antireflection structures that have been designed by using a genetic algorithm and fabricated by using oblique angle deposition. The antireflection coatings are designed for the wavelength range of 250 nm to 2500 nm and an incidence angle between 00 and 400. These nanostructured antireflection coatings are shown to enhance the optical transmission through transparent windows over a wide band of interest and minimize broadband reflection losses to less than one percent, a substantial improvement over conventional thin-film antireflection coating technologies. 展开更多
关键词 ANTIREFLECTION Coating NANOSTRUCTURED Layer OBLIQUE Angle DEPOSITION Silicon Dioxide Broadband omni-directionAL
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Wave Transmission in Dispersive Si-Based One Dimensional Photonic Crystal
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作者 Vipin Kumar B. Suthar +4 位作者 Arun Kumar Vinay Kumar Kh. S. Singh A. Bhargva S. P. Ojha 《Optics and Photonics Journal》 2012年第3期237-241,共5页
Transmission of electromagnetic waves through a Si-based one dimensional photonic crystal has been investigated. The proposed structure works as an omni-directional reflector for a certain range of wavelength for an a... Transmission of electromagnetic waves through a Si-based one dimensional photonic crystal has been investigated. The proposed structure works as an omni-directional reflector for a certain range of wavelength for an angle of incidence up to 55?. The structure works as a narrow band TM-polarization filter for an angle of incidence more than 55?, i.e. a filter which completely blocks TE-polarized waves but allows certain wavelengths of TM-polarized waves. But at an angle of incidence of 89?, the structure works as a multiple narrow band TM-polarization filter even though no defect layer is introduced inside the structure. It is also found that this multiple narrow pass-bands of TM-polarized waves can be tuned to a desired range of wavelength by changing the temperature of the structure. 展开更多
关键词 PHOTONIC CRYSTALS omni-directionAL REFLECTION Optical Filter
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声表面波扭矩检测系统的分段环状天线设计 被引量:1
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作者 熊志强 陈智军 +2 位作者 孙聪 朱卫俊 郭佳佳 《压电与声光》 CAS 北大核心 2020年第6期747-751,共5页
天线设计是实现无线无源声表面波扭矩检测的重要环节。针对待测扭矩的转轴结构设计了阅读器的分段环状天线,使用三维电磁仿真软件HFSS仿真了天线的中心频率、带宽、输入阻抗和方向图,在仿真优化的基础上制作了分段环状天线,并进行了相... 天线设计是实现无线无源声表面波扭矩检测的重要环节。针对待测扭矩的转轴结构设计了阅读器的分段环状天线,使用三维电磁仿真软件HFSS仿真了天线的中心频率、带宽、输入阻抗和方向图,在仿真优化的基础上制作了分段环状天线,并进行了相应的测试。测试结果表明,天线中心频率为431.6 MHz、带宽为424~440 MHz、输入阻抗接近50Ω,且天线所在平面具有较好的全向性。包括该阅读器天线的声表面波扭矩检测系统可实现较准确的扭矩测量,在-80~80 N·m时满量程误差为2.5%。 展开更多
关键词 扭矩检测 声表面波 分段环状天线 三维电磁仿真软件 全向性
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Residuals-Based Deep Least Square Support Vector Machine with Redundancy Test Based Model Selection to Predict Time Series 被引量:1
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作者 Yanhua Yu Jie Li 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2019年第6期706-715,共10页
In this paper, we propose a novel Residuals-Based Deep Least Squares Support Vector Machine(RBDLSSVM). In the RBD-LSSVM, multiple LSSVMs are sequentially connected. The second LSSVM uses the fitting residuals of the f... In this paper, we propose a novel Residuals-Based Deep Least Squares Support Vector Machine(RBDLSSVM). In the RBD-LSSVM, multiple LSSVMs are sequentially connected. The second LSSVM uses the fitting residuals of the first LSSVM as input time series, and the third LSSVM trains the residuals of the second, and so on. The original time series is the input of the first LSSVM. Additionally, to obtain the best hyper-parameters for the RBD-LSSVM, we propose a model validation method based on redundancy test using Omni-Directional Correlation Function(ODCF). This method is based on the fact when a model is appropriate for a given time series, there should be no information or correlation in the residuals. We propose the use of ODCF as a statistic to detect nonlinear correlation between two random variables. Thus, we can select hyper-parameters without encountering overfitting,which cannot be avoided by only cross validation using the validation set. We conducted experiments on two time series: annual sunspot number series and monthly Total Column Ozone(TCO) series in New Delhi. Analysis of the prediction results and comparisons with recent and past studies demonstrate the promising performance of the proposed RBD-LSSVM approach with redundancy test based model selection method for modeling and predicting nonlinear time series. 展开更多
关键词 time series prediction information REDUNDANCY residuals-based DEEP Least Squares Support Vector Machine (LSSVM) omni-directionAL Correlation Function (ODCF)
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Design of hexagon microstrip antenna for vehicle-to-vehicle communication 被引量:4
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作者 Hao Honggang Li Jiayu +1 位作者 Huang Daili Luo Wei 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2016年第4期69-76,共8页
Considering the shortcomings of the existing vehicle-to-vehicle(V2V) communication antennas, this paper proposes a regular hexagon broadband microstrip antenna. By loading shorting pins and etching V-shape slots wit... Considering the shortcomings of the existing vehicle-to-vehicle(V2V) communication antennas, this paper proposes a regular hexagon broadband microstrip antenna. By loading shorting pins and etching V-shape slots with different size at each angle of the regular hexagon patch, it realizes impedance matching and obtains better impedance bandwidth. The simulated results show that the relative bandwidth of this antenna reaches 35.55%, covers the frequency band of 4.74 GHz to 6.79 GHz. The antenna acquires an omni-directional radiation pattern in the horizontal plane whose out of roundness is less than 0.5 d B. In addition, the antenna is manufactured and tested, whose tested results are basically consistent with simulated results. Because the height of antenna is 3 mm, it is easy to be hidden on roof of a vehicle for V2 V communication. 展开更多
关键词 regular hexagon microstrip antenna shorting pins V-shape slots omni-directional radiation pattern V2V communication
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