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Conformal invariance and conserved quantities of dynamical system of relative motion 被引量:7
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作者 陈向炜 赵永红 李彦敏 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第8期3139-3144,共6页
This paper discusses in detail the conformal invariance by infinitesimal transformations of a dynamical system of relative motion. The necessary and sufficient conditions of conformal invariance and Lie symmetry are g... This paper discusses in detail the conformal invariance by infinitesimal transformations of a dynamical system of relative motion. The necessary and sufficient conditions of conformal invariance and Lie symmetry are given simultaneously by the action of infinitesimal transformations. Then it obtains the conserved quantities of conformal invariance by the infinitesimal transformations. Finally an example is given to illustrate the application of the results. 展开更多
关键词 dynamical system of relative motion infinitesimal transformation conformal invariance conserved quantities
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Special Lie symmetry and Hojman conserved quantity of Appell equations in a dynamical system of relative motion 被引量:4
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作者 解银丽 贾利群 罗绍凯 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第1期57-60,共4页
Special Lie symmetry and the Hojman conserved quantity for Appell equations in a dynamical system of relative motion are investigated. The definition and the criterion of the special Lie symmetry of Appell equations i... Special Lie symmetry and the Hojman conserved quantity for Appell equations in a dynamical system of relative motion are investigated. The definition and the criterion of the special Lie symmetry of Appell equations in a dynamical system of relative motion under infinitesimal group transformation are presented. The expression of the equation for the special Lie symmetry of Appell equations and the Hojman conserved quantity, deduced directly from the special Lie symmetry in a dynamical system of relative motion, are obtained. An example is given to illustrate the application of the results. 展开更多
关键词 dynamics of relative motion Appell equations special Lie symmetry Hojman conservedquantity
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Poisson theory and integration method for a dynamical system of relative motion 被引量:3
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作者 张毅 尚玫 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第2期321-325,共5页
This paper focuses on studying the Poisson theory and the integration method of dynamics of relative motion. Equations of a dynamical system of relative motion in phase space are given. Poisson theory of the system is... This paper focuses on studying the Poisson theory and the integration method of dynamics of relative motion. Equations of a dynamical system of relative motion in phase space are given. Poisson theory of the system is established. The Jacobi last multiplier of the system is defined, and the relation between the Jacobi last multiplier and the first integrals of the system is studied. Our research shows that for a dynamical system of relative motion, whose configuration is determined by n generalized coordinates, the solution of the system can be found by using the Jacobi last multiplier if (2n-1) first integrals of the system are known. At the end of the paper, an example is given to illustrate the application of the results. 展开更多
关键词 dynamics of relative motion Poisson theory method of integration Jacobi last multiplier
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Lie symmetry and its generation of conserved quantity of Appell equation in a dynamical system of the relative motion with Chetaev-type nonholonomic constraints 被引量:2
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作者 王肖肖 韩月林 +1 位作者 张美 贾利群 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第2期45-49,共5页
Lie symmetry and conserved quantity deduced from Lie symmetry of Appell equations in a dynamical system of relative motion with Chetaev-type nonholonomic constraints are studied.The differential equations of motion of... Lie symmetry and conserved quantity deduced from Lie symmetry of Appell equations in a dynamical system of relative motion with Chetaev-type nonholonomic constraints are studied.The differential equations of motion of the Appell equation for the system,the definition and criterion of Lie symmetry,the condition and the expression of generalized Hojman conserved quantity deduced from Lie symmetry for the system are obtained.The condition and the expression of Hojman conserved quantity deduced from special Lie symmetry for the system under invariable time are further obtained.An example is given to illustrate the application of the results. 展开更多
关键词 Chetaev-type nonholonomic constraints dynamics of relative motion Appell equation Lie symmetry
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Mei symmetry and Mei conserved quantity of the Appell equation in a dynamical system of relative motion with non-Chetaev nonholonomic constraints 被引量:1
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作者 王肖肖 孙现亭 +2 位作者 张美玲 韩月林 贾利群 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期6-10,共5页
The Mei symmetry and the Mei conserved quantity of Appell equations in a dynamical system of relative motion with non-Chetaev nonholonomic constraints are studied.The differential equations of motion of the Appell equ... The Mei symmetry and the Mei conserved quantity of Appell equations in a dynamical system of relative motion with non-Chetaev nonholonomic constraints are studied.The differential equations of motion of the Appell equation for the system,the definition and the criterion of the Mei symmetry,and the expression of the Mei conserved quantity deduced directly from the Mei symmetry for the system are obtained.An example is given to illustrate the application of the results. 展开更多
关键词 non-Chetaev nonholonomic constrained system dynamics of relative motion Appell equation Mei conserved quantity
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Perturbation to Symmetries and Adiabatic Invariants of Nonholonomic Dynamical System of Relative Motion 被引量:1
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作者 CHENXiang-Wei WANGMing-Quan WANGXin-Min 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第4期577-581,共5页
Based on the theory of symmetries and conserved quantities, the exact invariants and adiabatic invariants of nonholonomic dynamical system of relative motion are studied. The perturbation to symmetries for the nonholo... Based on the theory of symmetries and conserved quantities, the exact invariants and adiabatic invariants of nonholonomic dynamical system of relative motion are studied. The perturbation to symmetries for the nonholonomic dynamical system of relative motion under small excitation is discussed. The concept of high-order adiabatic invariant is presented, and the form of exact invariants and adiabatic invariants as well as the conditions for their existence are given. Then the corresponding inverse problem is studied. 展开更多
关键词 nonholonomic dynamical system of relative motion PERTURBATION exactinvariant adiabatic invariant
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Noether Symmetry and Noether Conserved Quantity of Nielsen Equation for Dynamical Systems of Relative Motion 被引量:1
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作者 解银丽 杨新芳 贾利群 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第1期111-114,共4页
Noether symmetry of Nielsen equation and Noether conserved quantity deduced directly from Noether symmetry for dynamical systems of the relative motion are studied. The definition and criteria of Noether symmetry of a... Noether symmetry of Nielsen equation and Noether conserved quantity deduced directly from Noether symmetry for dynamical systems of the relative motion are studied. The definition and criteria of Noether symmetry of a Nielsen equation under the infinitesimal transformations of groups are given. Expression of Noether conserved quantity deduced directly from Noether symmetry of Nielsen equation for the system are obtained. Finally, an example is given to illustrate the application of the results. 展开更多
关键词 dynamics of the relative motion Nielsen equations Noether symmetry Noether conserved quantity
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Lie Symmetries and Conserved Quantities of Systems of Relative Motion Dynamics
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作者 刘荣万 傅景礼 梅凤翔 《Journal of Beijing Institute of Technology》 EI CAS 1998年第3期221-225,共5页
Aim To study the Lie symmetries and conserved quantities of the dynamical equationsof relative motion for holonomic mechanical systems. Methods Lie's method of the invariance of ordinary differential equations u... Aim To study the Lie symmetries and conserved quantities of the dynamical equationsof relative motion for holonomic mechanical systems. Methods Lie's method of the invariance of ordinary differential equations under infinitesimal transformations was used. Results and Conclusion The determining equaiton of the Lie symmetries for the dynamical equationS of relative motion is established.The structure quation and the form conserved quantities are obtained. An example iD illustrate the application of the result is given. 展开更多
关键词 analytical mechanics dynamical of relative motion Lie symmetry conserved quantity
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3D dynamic motion of a dielectric micro-sphere within optical tweezers 被引量:4
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作者 Jing Liu Mian Zheng +1 位作者 Zhengjun Xiong Zhiyuan Li 《Opto-Electronic Advances》 SCIE 2021年第1期14-24,共11页
Known as laser trapping,optical tweezers,with nanometer accuracy and pico-newton precision,plays a pivotal role in single bio-molecule measurements and controllable motions of micro-machines.In order to advance the fl... Known as laser trapping,optical tweezers,with nanometer accuracy and pico-newton precision,plays a pivotal role in single bio-molecule measurements and controllable motions of micro-machines.In order to advance the flourishing applications for those achievements,it is necessary to make clear the three-dimensional dynamic process of micro-particles stepping into an optical field.In this paper,we utilize the ray optics method to calculate the optical force and optical torque of a micro-sphere in optical tweezers.With the influence of viscosity force and torque taken into account,we numerically solve and analyze the dynamic process of a dielectric micro-sphere in optical tweezers on the basis of Newton mechanical equations under various conditions of initial positions and velocity vectors of the particle.The particle trajectory over time can demonstrate whether the particle can be successfully trapped into the optical tweezers center and reveal the subtle details of this trapping process.Even in a simple pair of optical tweezers,the dielectric micro-sphere exhibits abundant phases of mechanical motions including acceleration,deceleration,and turning.These studies will be of great help to understand the particle-laser trap interaction in various situations and promote exciting possibilities for exploring novel ways to control the mechanical dynamics of microscale particles. 展开更多
关键词 optical tweezers 3D dynamic motion ray optics method Newton mechanical equations
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Genetic algorithm-fuzzy based dynamic motion planning approach for a mobile robot 被引量:1
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作者 王月海 洪炳熔 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2001年第3期228-232,共5页
Presents the mobile robots dynamic motion planning problem with a task to find an obstacle free route that requires minimum travel time from the start point to the destination point in a changing environment, due to t... Presents the mobile robots dynamic motion planning problem with a task to find an obstacle free route that requires minimum travel time from the start point to the destination point in a changing environment, due to the obstacle’s moving. An Genetic Algorithm fuzzy (GA Fuzzy) based optimal approach proposed to find any obstacle free path and the GA used to select the optimal one, points out that using this learned knowledge off line, a mobile robot can navigate to its goal point when it faces new scenario on line. Concludes with the optimal rule base given and the simulation results showing its effectiveness. 展开更多
关键词 GA fuzzy approach dynamic motion planning mobile robot OPTIMAL
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Dynamic Motion Resistance for Tracked Vehicle
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作者 Kai Zhao Mingming Dong +2 位作者 Zhiguo Sang Feng Liu Liang Gu 《Journal of Beijing Institute of Technology》 EI CAS 2017年第3期334-339,共6页
Based on previous achievements,a dynamic pressure-sinkage equation for saturated clay is established.First,aquasi-static penetration rate is selected,and the ratio of the dynamic penetration rate to the quasi-static r... Based on previous achievements,a dynamic pressure-sinkage equation for saturated clay is established.First,aquasi-static penetration rate is selected,and the ratio of the dynamic penetration rate to the quasi-static rate is used to characterize the degree of dynamic effect,then theβth power of the ratio is used to quantify the dynamic effect of sinkage.The dynamic effect exponentβis obtained using penetration tests with different penetration rates.Then,a dynamic motion resistance equation for a tracked vehicle is established based on the dynamic pressure-sinkage equation.The equation incorporates both penetration and bulldozing resistance.Finally,a series of simulation experiments with varying travel speeds and slip rates is carried out.The results show that an increase in the speed leads to stronger terrain stiffness,resulting in a decrease in sinkage and motion resistance.However,the enhancement effect becomes weaker with an increase in the travel speed. 展开更多
关键词 dynamic motion resistance tracked vehicle SINKAGE SLIP
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Ultrasonographic visualization of lower eyelid structures and dynamic motion analysis
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作者 Mohammad Taher Rajabi Konstantinos Papageorgiou +4 位作者 Shu-Hong Chang Imran Jarullazada Mehryar Taban Catherine J.Hwang Robert Alan Goldberg 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2013年第5期592-595,共4页
AIMTo define the ultrasonographic structure of normal lower eyelid anatomic compartments and their spacial relationship in dynamic motion.
关键词 lower eyelid ULTRASONOGRAPHY dynamic motion analysis
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NMR relaxation and diffusion studies to probe the motional dynamics of risperidone within PLGA microsphere
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作者 Deepak Kumar Samanwita Pal 《Magnetic Resonance Letters》 2023年第2期197-205,I0005,共10页
The present study aims to investigate the motional dynamics of risperidone within polylactic co-glycolic acid(PLGA)microsphere by employing solution state'H and 19F nuclear magnetic resonance(NMR)measurements.Risp... The present study aims to investigate the motional dynamics of risperidone within polylactic co-glycolic acid(PLGA)microsphere by employing solution state'H and 19F nuclear magnetic resonance(NMR)measurements.Risperidone,a second-generation fluorinated antipsychotic drug used for the treatment of schizophrenia is commercially marketed as PLGA microsphere formulation resulting in prolonged release of the drug in solution.Although the current trend in the pharmaceutical market is to develop drug formulation with long-acting release(LAR)products,complete physicochemical characterization of such formulations are scarce.Especially the effects of microsphere encapsulation on the motional properties and diffusion behavior of the drugs are not discussed adequately in any of the earlier reports.We therefore,have employed NMR relaxation and diffusion measurements to decipher the interaction of PLGA cavity water with risperidone.A detailed analysis of NMR relaxation rates confirmed the event of encapsulation and the presence of local motion in the non-fluorinated end of risperidone.Further,the relaxation data indicated a significant alteration in 19F chemical shift anisotropy(CSA)and CSA/dipole-dipole(DD)cross-correlated relaxation mechanism and decreased effect of solvent relaxation pointing out reduced water concentration within the microsphere cavity.'H and 19F diffusion coefficients of risperidone led to the information about hydrodynamic radius of risperidone in free and encapsulated states.Measurement of hydrodynamic radius supported the presence of limited water in PLGA cavity allowing higher translational mobility of risperidone after the encapsulation. 展开更多
关键词 Polylactic co-glycolic acid(PLGA)microsphere motional dynamics 1H and 19F NMR DIFFUSION Hydrodynamic radius Cross-correlated relaxation
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Dynamics of a spacecraft with large flexible appendage constrained by multi-strut passive damper 被引量:2
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作者 Ying-Hong Jia Shi-Jie Xu Quan Hu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2013年第2期294-308,共15页
This paper is concerned with the dynamics of a spacecraft with multi-strut passive damper for large flexible appendage.The damper platform is connected to the spacecraft by a spheric hinge,multiple damping struts and ... This paper is concerned with the dynamics of a spacecraft with multi-strut passive damper for large flexible appendage.The damper platform is connected to the spacecraft by a spheric hinge,multiple damping struts and a rigid strut.The damping struts provide damping forces while the rigid strut produces a motion constraint of the multibody system.The exact nonlinear dynamical equations in reducedorder form are firstly derived by using Kane's equation in matrix form.Based on the assumptions of small velocity and small displacement,the nonlinear equations are reduced to a set of linear second-order differential equations in terms of independent generalized displacements with constant stiffness matrix and damping matrix related to the damping strut parameters.Numerical simulation results demonstrate the damping effectiveness of the damper for both the motion of the spacecraft and the vibration of the flexible appendage,and verify the accuracy of the linear equations against the exact nonlinear ones. 展开更多
关键词 Dynamics·motion constraints·Multi-strut passive damper·Kane's equation
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Attitude control of spacecraft during propulsion of swing thruster 被引量:1
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作者 夏喜旺 荆武兴 +1 位作者 高长生 韦文书 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2012年第1期94-100,共7页
As for orbit transfer vehicle (OTV) with multiple satellites/payloads carried,the release of each payload will bring serious change to the mass center of OTV and the thrust produced by the swing thruster will form a r... As for orbit transfer vehicle (OTV) with multiple satellites/payloads carried,the release of each payload will bring serious change to the mass center of OTV and the thrust produced by the swing thruster will form a rather large disturbance to the attitude of OTV. Steering the nozzle to track the estimated center of mass (ECM) of OTV can reduce but not remove the disturbance due to the difference between the ECM and the practical mass center (PCM) of OTV. The practical propelling direction will change with the internal motion during the propulsion process and attitude control system should be enabled to guarantee that the propelling direction is collinear with the command. Since the structural parameters have changed,which is due to internal motion and fuel consumption,the dynamic model have to be formulated to determine these time-varying parameters and the required attitude of OTV should be determined as well. Modulating attitude quaternion results in quasi Euler angles. Based on the resulting quasi Euler angles,a novel attitude switching control law is introduced to control the variable-mass OTV. Simulation results show that,even in the case of structural asymmetry,control torque matrix asymmetry,attitude disturbance and strong coupling between the channels,the attitude of OTV can be controlled perfectly,and the proposed attitude control law is effective for the variable-mass OTV with swing thruster. 展开更多
关键词 variable-mass spacecraft relative motion dynamic modeling quasi Euler angle attitude switching control law
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Dynamics Modeling and Simulation of Autonomous Underwater Vehicles with Appendages 被引量:3
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作者 Yumin Su Jinxin Zhao Jian Cao Guocheng Zhang 《Journal of Marine Science and Application》 2013年第1期45-51,共7页
To provide a simulation system platform for designing and debugging a small autonomous underwater vehicle's (AUV) motion controller, a six-degree of freedom (6-DOF) dynamic model for AUV controlled by thruster an... To provide a simulation system platform for designing and debugging a small autonomous underwater vehicle's (AUV) motion controller, a six-degree of freedom (6-DOF) dynamic model for AUV controlled by thruster and fins with appendages is examined. Based on the dynamic model, a simulation system for the AUV's motion is established. The different kinds of typical motions are simulated to analyze the motion performance and the maneuverability of the AUV. In order to evaluate the influences of appendages on the motion performance of the AUV, simulations of the AUV with and without appendages are performed and compared. The results demonstrate the AUV has good maneuverability with and without appendages. 展开更多
关键词 autonomous underwater vehicle (AUV) motion performance dynamics modeling appendages simulation system
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Boundary Control of Coupled Nonlinear Three Dimensional Marine Risers 被引量:2
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作者 T. L. Nguyen K. D. Do J. Pan 《Journal of Marine Science and Application》 2013年第1期72-88,共17页
This paper presents a design of boundary controllers implemented at the top end for global stabilization of a marine riser in a three dimensional space under environmental loadings. Based on the energy approach, nonli... This paper presents a design of boundary controllers implemented at the top end for global stabilization of a marine riser in a three dimensional space under environmental loadings. Based on the energy approach, nonlinear partial differential equations of motion, including bending-bending and longitudinal-bending couplings for the risers are derived. The couplings cause mutual effects between the three independent directions in the riser's motions, and make it difficult to minimize its vibrations. The Lyapunov direct method is employed to design the boundary controller. It is shown that the proposed boundary controllers can effectively reduce the riser's vibration. Stability analysis of the closed-loop system is performed using the Lyapunov direct method. Numerical simulations illustrate the results. 展开更多
关键词 marine risers boundary control nonlinear dynamics equations of motion nonlinear couplings
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Dynamic flight stability of a bumblebee in forward flight 被引量:8
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作者 Yan Xiong Mao Sun 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2008年第1期25-36,共12页
The longitudinal dynamic flight stability of a bumblebee in forward flight is studied. The method of computational fluid dynamics is used to compute the aerodynamic derivatives and the techniques of eigenvalue and eig... The longitudinal dynamic flight stability of a bumblebee in forward flight is studied. The method of computational fluid dynamics is used to compute the aerodynamic derivatives and the techniques of eigenvalue and eigenvector analysis are employed for solving the equations of motion. The primary findings are as the following. The forward flight of the bumblebee is not dynamically stable due to the existence of one (or two) unstable or approximately neutrally stable natural modes of motion. At hovering to medium flight speed [flight speed Ue = (0-3.5)m s^-1; advance ratio J = 0-0.44], the flight is weakly unstable or approximately neutrally stable; at high speed (Ue = 4.5 m s^-1; J = 0.57), the flight becomes strongly unstable (initial disturbance double its value in only 3.5 wingbeats). 展开更多
关键词 Bumblebee Dynamic stability Forward flight Navier-Stokes simulation Natural modes of motion
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Robust description and recognition of various viewpoint dynamic textures 被引量:1
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作者 Qian Wang Jiuling Du Na Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2016年第4期920-925,共6页
The problem of recognizing natural scenes, such as water, smoke, fire, wind-blown vegetation and a flock of flying birds, is considered. These scenes exhibit the characteristic dynamic pattern, but have stochastic ext... The problem of recognizing natural scenes, such as water, smoke, fire, wind-blown vegetation and a flock of flying birds, is considered. These scenes exhibit the characteristic dynamic pattern, but have stochastic extent. They are referred to as dynamic texture(DT). In reality, the diversity of DTs on different viewpoints and scales are very common, which also bring great difficulty to recognize DTs. In the previous studies, due to no considering of the deformable and transient nature of elements in DT, the motion estimation method is based on brightness constancy assumption,which seem inappropriate for aggregate and complex motions. A novel motion model based on relative motion in the neighborhood of two-dimensional motion fields is proposed. The estimation of non-rigid motion of DTs is based on the continuity equation, and then the local vector difference(LVD) is proposed to characterize DT local relative motion. Spatiotemporal statistics of the LVDs is used as the representation of DT sequences. Excellent performances of classifying all DTs in UCLA database demonstrate the capability of the proposed method in describing DT. 展开更多
关键词 dynamic texture statistical representation motion estimation
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Measuring ground deformations caused by 2015 Mw7.8 Nepal earthquake using high-rate GPS data 被引量:1
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作者 Yong Huang Shaomin Yang +3 位作者 Xuejun Qiao Mu Lin Bin Zhao Kai Tan 《Geodesy and Geodynamics》 2017年第4期285-291,共7页
The April 25, 2015 Mw7.8 Nepal earthquake was successfully recorded by Crustal Movement Observation Network of China (CMONOC) and Nepal Geodetic Array (NGA). We processed the high-rate GPS data (1 Hz and 5 Hz) b... The April 25, 2015 Mw7.8 Nepal earthquake was successfully recorded by Crustal Movement Observation Network of China (CMONOC) and Nepal Geodetic Array (NGA). We processed the high-rate GPS data (1 Hz and 5 Hz) by using relative kinematic positioning and derived dynamic ground motions caused by this large earthquake. The dynamic displacements time series clearly indicated the displacement amplitude of each station was related to the rupture directivity. The stations which located in the di- rection of rupture propagation had larger displacement amplitudes than others. Also dynamic ground displacement exceeding 5 cm was detected by the GPS station that was 2000 km away from the epicenter. Permanent coseismic displacements were resolved from the near-field high-rate GPS stations with wavelet decomposition-reconstruction method and P-wave arrivals were also detected with S transform method. The results of this study can be used for earthquake rupture process and Earthquake Early Warning studies. 展开更多
关键词 High-rate GPS Mw7.8 Nepal earthquake Dynamic ground motion Permanent coseismic displacements P-wave arrival detection
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