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China Ocean Engineering 2019年第4期33卷 459-467页

作者： HU Xiao-feng ZHANG Xin-shu YOU Yun-xiang DUAN Jin-long State Key Laboratory of Ocean Engineering School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE) School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China

A phenomenological model for predicting the vortex-induced motion (VIM) of a single-column platform with non- linear stiffness has been proposed. The VIM model is based on the couple of the Duffing-van der Pol oscillators and the motion equations with non-linear terms. The model with liner stiffness is presented for comparison and their results are compared with the experiments in order to calibrate the model. The computed results show that the predicted VIM amplitudes and periods of oscillation are in qualitative agreements with the experimental data. Compared with the results with linear stiffness, it is found that the application of non-linear stiffness causes the significant reductions in the in-line and transverse motion amplitudes. Under the non-linear stiffness constraint, the lock-in behavior is still identified at 8motion amplitudes. Furthermore, the computed results for different aspect ratios indicate that the in-line and transverse motion amplitudes increase with the growth of aspect ratio, and the range of lock-in region is enlarged for the large aspect ratio.

关键词： vortex-induced motion single-column platform wake oscillators non-linear stiffness

Best practices for model-based and simulation-aided engineering of power transmission and motion control systems

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Chinese Journal of Aeronautics 2019年第1期32卷 186-199页

作者： Jean-Charles MARE Institut Clément Ader (CNRS UMR 5312)

This paper deals with the modelling and simulation of aircraft systems, in particular for power transmission and control. It is intended to review, propose and disseminate best practices for making model-based/simulation-aided engineering more efficient at any phase of the system life cycle. The proposals are aimed at creating value, not only by increasing the performance of the product under study but also by shortening the time to market, capitalizing knowledge, mitigating risks and facilitating concurrent engineering. The needs associated with the engineering activities are firstly identified to define a set of requirements for the models. Then, these requirements are used to drive the considerations leading to model development, focusing in particular on the process,modelled physical effects, modelling level, model architecting and concurrent engineering. The third part deals with the model implementation, giving special consideration to the different types of models, causalities, parameterization, implementation and verification. Each part is illustrated by examples related to safety critical actuators.

关键词： Actuator Aerospace Architecture Causality Modelling motion control Power transmission Simulation

SIZE DISTRIBUTION OF DROPLETS ABOVE A ROTATING STREAM TRAY AND MODEL OF DROPLET motion THEREIN

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Chinese Journal of Chemical Engineering 1997年第2期5卷 35-42页

作者：陈建孟谭天恩 Department of Chemical Engineering Zhejiang University of Technology Department of Chemical Engineering Zhejiang University

Droplet size distributions have been investigated with a two-probe system above a rotatingstream tray of 300 mm diameter.The measured distributions are found to follow the upper limitedlognormal distribution with three parameters dependent primarily on gas hole F-factor.A probabilitymethod is used to describe the initial state of the droplet population above the tray,and a model fordroplet motion is presented.The results computed with model agree well with experimental data.

关键词： rotating stream tray droplet size distribution model for droplet motion

Experimental investigation of influence of strake wings on self-induced roll motion at high angles of attack

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Chinese Journal of Aeronautics 2016年第6期29卷 1591-1601页

作者： Geng Xi Shi Zhiwei Cheng Keming College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics

The modern high performance air vehicles are required to have extreme maneuverability,which includes the ability of controlled maneuvers at high angle of attack. However, the nonlinear and unsteady aerodynamic phenomena, such as flow separation, vortices interaction, and vortices breaking down, will occur during the flight at high angle of attack, which could induce the uncommanded motions for the air vehicles. For the high maneuverable and agile air missile, the nonlinear roll motions would occur at the high angle of attack. The present work is focused on the selfinduced nonlinear roll motion for a missile configuration and discusses the influence of the strake wings on the roll motion according to the results from free-to-roll test and PIV measurement using the models assembled with different strake wings at a = 60°. The free-to-roll results show that the model with whole strake wings(baseline), the model assembled with three strake wings(Case A)and the model assembled with two opposite strake wings(Case C) experience the spinning, while the model assembled with two adjacent strake wings(Case B), the model assembled with one strake wing(Case D) and the model with no strake wing(Case E) trim or slightly vibrate at a certain "×"rolling angle, which mean that the rolling stability can be improved by dismantling certain strake wings. The flow field results from PIV measurement show that the leeward asymmetric vortices are induced by the windward strake wings. The vortices would interact the strake wings and induce crossflow on the downstream fins to degrade the rolling stability of the model. This could be the main reason for the self-induced roll motion of the model at a = 60°.

关键词： Cruciform fins High angle of attack PIV Roll motion Strake wing

Dual-quaternion-based modeling and control for motion tracking of a tumbling target

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Journal of Systems Engineering and Electronics 2019年第5期30卷 985-994页

作者： PENG Xuan SHI Xiaoping GONG Yupeng Control and Simulation Center Harbin Institute of TechnologyHarbin 150001China Research Center of Satellite Technology Harbin Institute of TechnologyHarbin 150001China

This paper investigates the problem of controlling a chasing spacecraft(chaser)to track and rendezvous with an uncontrolled target.Based on the actual situation,the torque-free motion of an axisymmetric prolate rigid body is employed to represent the short-term attitude motion of the tumbling target.By taking advantage of the dual quaternion’s compact and efficient description of the general rigid motion,the coupled and integrated model of the 6-degree-of-freedom(6-DOF)relative motion between the chaser and the tumbling target is derived in the chaser’s body fixed frame after taking full consideration of coordinate transformation.Based on the logarithm of dual quaternion,a sliding mode control(SMC)law based on the exponential reaching law and the continuous relay function is brought forward to address the problem of synchronization control of the 6-DOF relative motion.Simulation results illustrate the effectiveness of the proposed method.

关键词： tumbling target dual-quaternion coupled dynamics relative motion

All-optical motion control of metal nanoparticles powered by propulsion forces tailored in 3D trajectories

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Photonics Research 2021年第1期9卷 1-12页

作者： OSéARODRIGO MERCEDES ANGULO TATIANA ALIEVA Universidad Complutense de Madrid Facultad de Ciencias FisicasCiudad Universitarias/nMadrid 28040Spain

Increasing interest has been drawn to optical manipulation of metal(plasmonic)nanoparticles due to their unique response on electromagnetic radiation,prompting numerous applications in nanofabrication,photonics,sensing,etc.The familiar point-like laser tweezers rely on the exclusive use of optical confinement forces that allow stable trapping of a single metal nanoparticle in 3 D.Simultaneous all-optical(contactless)confinement and motion control of single and multiple metal nanoparticles is one of the major challenges to be overcome.This article reports and provides guidance on mastering a sophisticated manipulation technique harnessing confinement and propulsion forces,enabling simultaneous all-optical confinement and motion control of nanoparticles along 3 D trajectories.As an example,for the first time to our knowledge,programmable transport of gold and silver nanospheres with a radius of 50 and 30 nm,respectively,along 3 D trajectories tailored on demand,is experimentally demonstrated.It has been achieved by an independent design of both types of optical forces in a single-beam laser trap in the form of a reconfigurable 3 D curve.The controlled motion of multiple nanoparticles,far away from chamber walls,allows studying induced electrodynamic interactions between them,such as plasmonic coupling,observed in the presented experiments.The independent control of optical confinement and propulsion forces provides enhanced flexibility to manipulate matter with light,paving the way to new applications involving the formation,sorting,delivery,and assembling of nanostructures.

关键词： motion walls silver

Influence of Center of Gravity Location on Flight Dynamic Stability in a Hovering Tailless FW-MAV: Lateral motion

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Journal of Bionic Engineering 2020年第1期17卷 148-160页

作者： Loan Thi Kim Au Hoon Cheol Park Department of Smart Vehicle Engineering and Artificial Muscle Research Center Konkuk UniversitySeoul 05029Korea

This paper reports the effect of the Center of Gravity(CG)position on lateral flight dynamic stability of hovering KUBeetle,a tailless FW-MAV,providing further insights on the effects of asymmetries in body mass distribution and wing kinematics.For the current study,the standard linearized equations of motion were applied as in the previous work on longitudinal dynamic stability.The stability derivatives were acquired using the computational fluid dynamic methods via the commercial software of ANSYS Fluent.There exists a stable region for CG between 2.6%and 3.5%of the mean chord below the wing pivot point,in which the lateral motion of hovering KUBeetle is passively stable.For CG below the stable region,because of an unstable oscillatory mode,the lateral motion of the FW-MAV is unstable but can be stabilized using rolling rate feedback.For CG above the stable region,because of a divergence mode,the system remains unstable even with the rolling rate feedback.Comparison with other works on an FW-MAV based on a quasi-steady aerodynamic model and on insect showed similar characteristics for flapping flight.It is also interesting to note that the asymmetries in body mass and wing kinematics can enlarge the stable region of the system by a non-zero Ixz which approaches the root square of√IxIz,a negative LrNp,and a positive Ix2(Ir+Np).Combining the current result with that of the previous work on longitudinal motion,the most beneficial region of the CG for full 6-DOF flight dynamic stability of hovering KUBeetle was suggested.

关键词： FW-MAV center of gravity flight dynamic stability lateral motion asymmetry computational fluid dynamics bioinspired flight

Optimal and interactive keyframe selection for motion capture

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Computational Visual Media 2019年第2期5卷 171-191页

作者： Richard Roberts J.P.Lewis Ken Anjyo Jaewoo Seo Yeongho Seol Victoria University of Wellington WellingtonNew Zealand SEED Electronic ArtsLos AngelesUnited States OLM Digital TokyoJapan Pinscreen Los AngelesUnited States Weta Digital WellingtonNew Zealand

motion capture is increasingly used in games and movies, but often requires editing before it can be used, for many reasons. The motion may need to be adjusted to correctly interact with virtual objects or to fix problems that result from mapping the motion to a character of a different size or, beyond such technical requirements, directors can request stylistic changes.Unfortunately, editing is laborious because of the lowlevel representation of the data. While existing motion editing methods accomplish modest changes, larger edits can require the artist to "re-animate" the motion by manually selecting a subset of the frames as keyframes.In this paper, we automatically find sets of frames to serve as keyframes for editing the motion. We formulate the problem of selecting an optimal set of keyframes as a shortest-path problem, and solve it efficiently using dynamic programming. We create a new simplified animation by interpolating the found keyframes using a naive curve fitting technique. Our algorithm can simplify motion capture to around 10% of the original number of frames while retaining most of its detail. By simplifying animation with our algorithm, we realize a new approach to motion editing and stylization founded on the timetested keyframe interface. We present results that show our algorithm outperforms both research algorithms and a leading commercial tool.

关键词： motion capture motion editing keyframe animation dynamic programming

Modeling and motion Simulation for A Flying-Wing Underwater Glider with A Symmetrical Airfoil

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China Ocean Engineering 2019年第3期33卷 322-332页

作者： ZHAO Liang WANG Peng SUN Chun-ya SONG Bao-wei School of Marine Science and Technology Northwestern Polytechnical University Xi’an 710072 China The 719 Research Institute of CSIC Wuhan 430064 China

The flying-wing underwater glider (UG), shaped as a blended wing body, is a new type of underwater vehicle and still requires further research. The shape layout and the configuration of the internal actuators of the flying-wing UG are different from those of "legacy gliders" which have revolving bodies, and these two factors strongly affect the dynamic performance of the vehicle. Considering these differences, we propose a new configuration of the internal actuators for the flying-wing UG and treat the flying-wing UG as a multi-body system when establishing its dynamic model. In this paper, a detailed dynamic model is presented using the Newton-Euler method for the flying-wing UG. Based on the full dynamic model, the effect of the internal actuators on the steady gliding motion of vehicle is studied theoretically, and the relationship between the state parameters of the steady gliding motion and the controlled variables is obtained by solving a set of equilibrium equations. Finally, the behaviors of two classical motion modes of the glider are analyzed based on the simulation. The simulation results demonstrate that the motion performance of the proposed flying-wing UG is satisfactory.

关键词： flying-wing underwater glider blended-wing-body dynamic modeling motion simulation steady motion

Mapping of ground motion amplifications for the Fraser River delta in Greater Vancouver, Canada

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Earthquake Engineering and Engineering Vibration 2019年第4期18卷 703-717页

作者： Byungmin Kim Ulsan National Institute of Science and Technology

The Fraser River delta in Greater Vancouver, Canada consists of deep soft deposits of silts and clays, and it is well known that the deep soil deposits can amplify the low frequency contents of ground motions. This study aims to investigate the eff ects of deep soil deposits in the delta on ground motion amplifi cations by using thorough site response simulations that account for the full soil profi les and a suite of recorded ground motions that covers a wide range of intensity levels. Based on both equivalent-linear and nonlinear site response simulations, the eff ects of soil depth (represented by natural period of the soil, TS) on ground motion amplifi cations for various spectral periods are clearly demonstrated. The ground motion amplifi cation maps for various spectral periods and rock ground motion intensity levels are also generated to be used in the regional seismic hazard assessment for infrastructure. It is found that ground motions for long periods are substantially amplifi ed in the center of the delta, while those for short periods are de-amplifi ed when input rock motions are large.

关键词： Fraser River delta ground motion amplifi cation deep soil deposits site response analysis basin depth