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Effect of Different Types of Wing-Wing Interactions in Flapping MAVs

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Journal of Bionic Engineering 2017年第1期14卷 60-74页

作者： Wee Beng Tay temasek laboratories National University of Singapore 5A Engineering Drive 1 117411 Singapore

Wing-Wing Interaction （WWI）, such as the Clap and Fling Motion （CFM）, occurs when two wings are flapping close together, improving performance. We intend to design a hovering Flapping Micro Aerial Vehicle （FMAV） which makes use of WWI. We investigate the effects of flexibility, kinematic motions, and two- to six-wing flapping configurations on the FMAV through numerical simulations. Results show that a rigid spanwise and flexible chordwise wing produces the highest lift with minimum power. The smoothly varying sinusoidal motion, which is visually similar to the CFM, produces similar lift in comparison to the CFM, while having lower peak power requirement. Lastly, lift produced by each wing of the two-, four-, six-wing configurations is approximately equal. Hence more wings generate higher total lift force, but at the expense of higher drag and power requirement. These results will be beneficial in the understanding of the underlying aerodynamics of WWI, and in improving the performance of our FMAV.

关键词： flapping wings MAV immersed boundary methods clap and fling

Online schedule for autonomy of multiple unmanned aerial vehicles

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Science China(Information Sciences) 2017年第7期60卷 217-229页

作者： Kemao PENG Feng LIN Ben M.CHEN temasek laboratories National University of Singapore Department of Electrical and Computer Engineering National University of Singapore

An online rectangle based scheduling algorithm(RSA) is developed to improve autonomy of multiple unmanned aerial vehicles(UAVs) to search a field of forest together. The purposes of RSA are to online decide the number of the UAVs to be assigned and to schedule the path for the assigned UAVs to search the missed areas resulted from the previous search. The main ideas of RSA are to cover each separated zone of the missed areas with a rectangle and then to schedule the path to search the rectangles. Thus, RSA is robust against the unknown shapes and sizes of the missed areas. The forest search is applied to verify the online RSA in simulation. The simulation results demonstrate that the online RSA is successful to decide the number of the UAVs to be assigned and to schedule the path for the assigned UAVs to search the missed areas.

关键词： online schedule mission planning autonomy of UAVs multiple UAVs algorithms

Laterally pre-compressed SiC tiles against long rod impact

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Defence Technology（防务技术） 2018年第5期14卷 585-589页

作者： Bo-yang Luo Wei-liang Goh Zhong Chen Jian-ming Yuan temasek laboratories Nanyang Technological University School of Materials Science and Engineering Nanyang Technological University

A combined experimental and computational study was carried out to investigate ballistic performance of laterally preload compressed SiC tile against long rod impact. A 100 x 100 by 20 mm thick SiC tile was pushed into a 5 mm thick steel frame at high temperature of 430 ℃ so that after cool down to room temperature, the lateral preload compressive stress was developed in the SiC tiles. Depth of penetration tests of the SiC tiles with and without pre-stress were performed, where tungsten alloy long rods at a nominal velocity of 1240 m/s were launched to hit the SiC tiles backed by the steel blocks. Compared with the SiC tiles without any pre-stress, the pre-compressed SiC tiles were found to reduce significantly the residual penetration in the backing block. Simulations were carried out using the LS-dyna hydrocode,taking account of preload stress. The simulations showed that the lateral preload compression strengthened the intact SiC tiles and dwell occurred in the early penetration stage, eroding the striking long rod efficiently.

关键词： Pre-compressed SiC tile DOP test WHA long rod

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Guest editorial

International Journal of Intelligent Computing and Cybernetics 2017年第4期10卷 410-411页

作者： Delin Luo Feng Lin Department of Automation Xiamen UniversityXiamenChina temasek laboratories National University of SingaporeSingapore

Autonomous control of Unmanned Aerial System(UAS)is that UASs can make decisions in the flight and carry out missions autonomously according to the scheduled tasks and rules through online sensing the surrounding *** cooperation,UASs can share information among individual agents and work together to accomplish complicated mission which would not be possible for a single agent *** the development of UAS technology,autonomous control has become one of the hot topics and key technologies in UAS research field.

关键词： agent individual autonomous

Design and implementation of a leader-follower cooperative control system for unmanned helicopters

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控制理论与应用（英文版） 2010年第1期8卷 61-68页

作者： Ben YUN Ben M. CHEN Kai Yew LUM Tong H. LEE Department of Electrical & Computer Engineering National University of Singapore Singapore 117576 temasek laboratories National University of Singapore Singapore 117508

In this paper, we present a full scheme for the cooperative control of multiple unmanned aerial vehicle （UAV） helicopters. We adopt the leader-follower pattern to maintain a fixed geometrical formation while navigating the UAVs following certain trajectories. More specifically, the leader is commanded to fly on some predefined trajectories, and each follower is controlled to maintain its position in formation using the measurement of its inertial position and the information of the leader position and velocity, obtained through a wireless modem. More specifications are made for multiple UAV formation flight. In order to avoid possible collisions of UAV helicopters in the actual formation flight test, a collision avoidance scheme based on some predefined alert zones and protected zones is employed. Simulations and experimental results are presented to verify our design.

关键词： Unmanned aerialvehicles Cooperative control Flight formation Collision avoidance

Investigation on energy output structure of explosives near-ground explosion

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Defence Technology（防务技术） 2020年第2期16卷 290-298页

作者： Wen-long Xu Cheng Wang Jian-ming Yuan Wei-liang Goh Tao Li State Key Lab of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China temasek laboratories Nanyang Technological University50 Nanyang Drive637553Singapore

In order to give the energy output structure of typical explosives near-ground explosion in real ground conditions,the free-field shockwave,ground reflection shockwave and Mach wave overpressure time history of composition B explosive,RDX explosive and aluminized explosive were measured by air pressure sensors and ground pressure *** shape of the free-field shock wave,ground reflection shock wave,and Mach wave and explosion flame were captured by high-speed *** experimental results show that,at the same horizontal distance from the initiation point,the peak overpressure of explosive shock wave of composition B explosive,both in the air and on the ground,is less than that of RDX and aluminized *** a distance of 3.0 m from the initiation point,the peak overpressure of aluminized explosives is slightly less than that of RDX *** to the exothermic effect of aluminum powder,the pressure drop of aluminized explosives is slower than that of RDX *** 5.0 m from the initiation point,the peak overpressure of aluminized explosives is larger than that of RDX *** the same position from the initiation point,among the three kinds of explosives,the impulse of aluminized explosives is the maximum and the impulse of composition B explosives is the *** the increase of the horizontal distance from the initiation point,the height of Mach triple-points(Mach steam)of the three explosives increases *** the same horizontal distance from the initiation point,there is poorly difference in the height of Mach triple-points between aluminized explosive and RDX explosive,and the height of Mach triple-points of composition B explosive is much smaller than that of other two *** maximum diameter and duration of the fireball formed by aluminized explosives are the largest,followed by composition B explosive,and the maximum diameter and duration of the fireball formed by RDX explosive are the smallest.

关键词： Near-ground blast Reflected wave Marcher steam Aluminized explosives

Bore-center annular shaped charges with different liner materials penetrating into steel targets

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Defence Technology（防务技术） 2019年第5期15卷 796-801页

作者： Wen-long Xu Cheng Wang Jian-ming Yuan Tao Deng State Key Lab of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China temasek laboratories Nanyang Technological University50 Nanyang Drive637553Singapore

The bore-center annular shaped charge(BCASC)is a new type of shaped charge which can generate a larger-diameter hole in steel targets than classical shaped *** this paper,the influence of three liner materials,***,nickel and copper,on BCASC formation and penetrating into steel targets was investigated by experiment and numerical *** simulation results were well consistent with the experimental *** study showed that,at 0.50D standoff distance,the axial velocity of the molybdenum projectile was lower than that of the nickel and copper *** nickel and copper projectiles had almost the same head *** absolute values of the radial velocity of the molybdenum projectile head was lower than that of the nickel and copper ***,at 0.75D standoff distance,the absolute values of the radial velocity of the molybdenum projectile head became much greater than that of the nickel and copper projectile *** projectile formed by BCASC with the molybdenum liner had the highest penetration depth of 61.5 mm,which was 10.0%and 21.3%higher than that generated by the copper and nickel projectiles.

关键词： Annular shaped charge Liner material Formation Numerical simulation

Low-cost design of stealthy hardware trojan for bit-level fault attacks on block ciphers

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Science China(Information Sciences) 2017年第4期60卷 235-237页

作者： Fan ZHANG Xinjie ZHAO Wei HE Shivam BHASIN Shize GUO College of Information Science and Electrical Engineering Zhejiang University Science and Technology on Communication Security Laboratory Institute of North Electronic Equipment temasek laboratories Nanyang Technological University

Fault analysis is a very powerful technique to break cryptographic *** particular,bitlevel fault analysis(BLFA),where faults are injected by flipping one or a few isolated bits,are among the most efficient of the *** requires both precise fault injection capabilities and sophisticated key extraction *** fault analysis(AFA)[1]is a good analysis technique for *** with differential fault analysis(DFA),AFA relies on the automation from machine *** it fully utilizes the leakages

关键词： Low-cost design of stealthy hardware trojan for bit-level fault attacks on block ciphers HTH

Transistor level SCA-resistant scheme based on fluctuating power logic

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Science China(Information Sciences) 2017年第10期60卷 270-272页

作者： Liang GENG Fan ZHANG Jizhong SHEN Wei HE Shivam BHASIN Xinjie ZHAO Shize GUO College of Information Science and Electronic Engineering Zhejiang University Science and Technology on Communication Security Laboratory temasek laboratories Nanyang Technological University The Institute of North Electronic Equipment

Dear editor,The main objective of side-channel analysis(SCA)is to extract the secret key using physical leakages from underlying fundamental logic *** analysis(PA)is one type of SCA,such as simple power analysis(SPA),... 详细信息

关键词： SCA Transistor level SCA-resistant scheme based on fluctuating power logic

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