Математическая модель динамики периферийного стыковочного механизма с накоплением кинетической энергии сближения космических аппаратов

2019 ◽  
pp. 98-108
Author(s):  
Andrey Vladimirovich YASKEVICH
Keyword(s):  
Kinetic Energy ◽  
Key Words ◽  
Interaction Analysis ◽  
Kinematics And Dynamics ◽  
Spacecraft Motion ◽  
Math Model ◽  
Motion Equations ◽  
Docking Mechanism ◽  
Inertia Properties ◽  
First Contact

The new peripheral docking mechanism is part of a docking unit designed in compli-ance with the International Docking System Standard (IDSS). The mechanism kinematics is based on the Gough-Stewart platform. Spring mechanisms are used for transformation of spacecraft approach kinetic energy. However, traditional damping is replaced by energy ac-cumulation. Therefore, the design includes new devices. The dynamic math model of the dock-ing mechanism described in this paper takes into account its main features – kinematics, inertia properties and generation of internal active forces by separate devices. Along with spacecraft motion equations and algorithms of docking unit contact interaction analysis, this model is part of a docking math model used for the analysis of kinematics and dynamics processes from the first contact to the end of retraction. Key words: spacecraft, docking mechanism, dynamics equations.

SPACECRAFT DOCKING DYNAMIC FEATURES BY USING A PERIPHERAL MECH-ANISM WITH ACCUMULATION OF APPROACH KINETIC ENERGY

2019 ◽  
pp. 109-120
Author(s):  
A.V. Yaskevich
Keyword(s):  
Kinetic Energy ◽  
Key Words ◽  
Dynamic Process ◽  
Dynamic Features ◽  
Private Companies ◽  
National Space ◽  
Docking Mechanism ◽  
And Control

Up to now, several docking systems have been developed under the International Docking System Standard (IDSS) by national space agencies and private companies. Docking mechanisms of these systems are based on different design and control principles. Thus a new peripheral docking mechanism, with more simple kinematics and design than that used in previous APAS docking unit, has been developed by Rocket and Space Corporation «Energia». An accumulation of spacecraft approach kinetic energy instead of traditional damping is used in this mechanism. It allows to move forward the docking ring for capture improvement and to ensure slowdown. Main features of spacecraft docking dynamic process with the use of this mechanism are described in this paper. Key words: spacecraft, docking mechanisms, docking dynamics.

Choice of energy accumulator parameters for a new peripheral docking mechanism

2019 ◽  
pp. 55-66
Author(s):  
Andrey V. Yaskevich ◽  
Ivan Ye. Chernyshev
Keyword(s):  
Key Words ◽  
Mechanical System ◽  
Initial Position ◽  
Assembly Process ◽  
Mechanical Assembly ◽  
Energy Accumulation ◽  
Active Unit ◽  
Docking Mechanism ◽  
First Contact

Spacecraft docking is a controlled on-orbit mechanical assembly process realized using active and passive docking units. The docking mechanism of the active unit provides capture conditions, attenuation of active spacecraft approach energy, alignment and retraction of the docking units before their hard connection. A kinematical scheme of a new peripheral docking mechanism is considered in this paper. Instead of energy damping, it is based on energy accumulation using springs with controlled recoil blocking. The blocking is activated before docking and keeps the docking mechanism in its initial position. On the first contact signal, the blocking is switched off releasing the energy of compressed springs for quick forward moving of the docking ring and improving capture. The blocking is activated again after capture and approach energy is accumulated by the springs without returning to the mechanical system. Avoiding contacts of docking mechanism links between each other and with the docking unit body is important for peripheral mechanisms due to their design. A procedure for choosing parameters of an energy accumulator that allows attenuating a max permissible energy without link contacts and without exceeding the max permissible value of the axial interface load is considered here. Key words: spacecraft, docking, docking mechanism.

Variation in kinematics and dynamics of the landing flights of pigeons on a novel perch

1998 ◽  
Vol 201 (24) ◽  
pp. 3309-3316 ◽  
Author(s):  
P. R. Green ◽  
P. Cheng
Keyword(s):  
Body Weight ◽  
Kinetic Energy ◽  
Horizontal Velocity ◽  
Maximum Force ◽  
Kinematics And Dynamics ◽  
Video Recordings

Pigeons made 10 flights to a novel perch. Kinematic measurements of these flights were obtained from video recordings, and the forces exerted on the perch on each landing were measured. There was wide variation(20-fold range) in the kinetic energy of the pigeons just before landing,arising almost entirely from variation in horizontal velocity. The maximum force exerted on the perch varied in magnitude from approximately twice to eight times the pigeons' body weight, and in direction from 40 to 90 below the horizontal. In landings with high final kinetic energy, the maximum force exerted on the perch was larger and was applied at a shallower angle than in those with low final kinetic energy. Landing flights with high final kinetic energy showed straighter trajectories and a larger peak deceleration during the last 300 ms of approach flight than those with low final kinetic energy, which had downward-curving trajectories and a more prolonged and steady pattern of deceleration. Mean final kinetic energy was lower in the first two landings made on the perch than in subsequent landings, indicating that pigeons are more likely to adopt a slow,downward-curving approach to a novel perch and a fast, straight approach to a familiar one.

scholarly journals Kinematics and dynamics of the ballistic impact behavior for an oil palm empty fruit bunch fiber reinforced bio-composite

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6123-6134
Author(s):  
Siti Nikmatin ◽  
Bambang Hermawan ◽  
Irmansyah ◽  
Mohammad Nur Indro ◽  
Mochammad Danny Sukardan ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Ballistic Impact ◽  
Impact Behavior ◽  
Kinematics And Dynamics ◽  
Empty Fruit Bunch ◽  
Fiber Reinforced ◽  
Polyester Resins ◽  
Ballistic Test ◽  
The Impact ◽  
Main Material

The ballistic impact behavior of oil empty fruit bunch fiber reinforced bio-composites was studied. Epoxy and polyester resins were used as the main material and were evaluated as a matrix to determine their capability. The ballistic test was performed using a 9 mm handgun and a jacketed hollow point round. A model based on kinematics and dynamics was used to calculate the decrease in velocity of the projectile with a constant deceleration. The energy lost during the impact was calculated based on the theory of kinetic energy. The epoxy bio-composite was able to hold a projectile more successfully than the polyester bio-composite at a certain penetration depth. The curve of the decrease in velocity for both of the resins was exponentially distributed. An 18% epoxy bio-composite was able to more successfully stop the projectile at a penetrative depth of 2.14 mm and was able to absorb all the kinetic energy generated (408 J).

scholarly journals Upper tropospheric energetics of standing eddies In wave number domain during contrasting Monsoon activity over India

MAUSAM ◽  
2021 ◽  
Vol 43 (4) ◽  
pp. 403-410
Author(s):  
S.S. BAWISKAR ◽  
S.M. SINGH
Keyword(s):  
Energy Source ◽  
Kinetic Energy ◽  
Interaction Analysis ◽  
Standing Waves ◽  
Wave Interaction ◽  
Wave Number ◽  
Mean Flow ◽  
S Wave ◽  
Flow Interaction ◽  
Energy Equations

The upper tropospheric energetics of the standing eddies in wave number domain during contrasting monsoon' activity over India have been investigated. Two normal monsoon years (1970. 1971) and two drought monsoon years (1972, 1979) are considered for a comparative study, Energy equations of Saltzman (1957) are used to compute wave-wave Interaction and wave to zonal mean flow Interaction. Analysis of the results show that the standing eddies in the region of tropical easterlies (5°S-24 .2°N) have larger kinetic energy than those in the region of southern hemispheric, westerlies (24.2°S-5°S). Wave to zonal mean flow interaction of all waves (waves 1-15) Indicate that the standing eddies are a source of kinetic energy to zonal mean flow ID the region of easterlies and there sink of kinetic energy to zonal mean flow in the region of westerlies. In the region of easterlies planetary standing waves (waves 1-2) are the major kinetic energy source to other standing waves and wave-wave Interaction of all waves leads to positive Imbalance of kinetic energy during normal monsoon years (1970, 1971) and negative imbalance, of kinetic, energy during drought monsoon years (1972, 19~9). In the region of westerlies the imbalance of kinetic energy IS negative during normal monsoon years and positive during drought monsoon years.

The Kinematics and Dynamics of Ciliary Fluid Systems

1968 ◽  
Vol 49 (3) ◽  
pp. 617-629
Author(s):  
C. E. MILLER
Keyword(s):  
Reynolds Number ◽  
Kinetic Energy ◽  
Energy Loss ◽  
Reynolds Numbers ◽  
Kinematics And Dynamics ◽  
Newtonian Mechanics ◽  
Mucociliary System ◽  
Fluid Systems ◽  
Two Systems ◽  
Sophisticated Model

1. The difficulties of directly applying the methods of Newtonian mechanics to solve the problem of mucus flow in the mammalian trachea are discussed. 2. In order to circumvent these difficulties, a sophisticated model of the mucociliary system, called the circular rheociliometer, was constructed. A brief account is given of the model and the homomorphic relation it has to the mucociliary system of mammal. 3. Kinematic experiments are described in which observations on the model are compared with observations on the mucociliary system of the cat's trachea. 4. A coefficient of energy, which is the ratio of energy loss in the fluid to the kinetic energy supplied by the cilia, is developed. The coefficient of energy is plotted against the Reynolds number for the model and for the cat's trachea. It is shown that both sets of data fall within the same range of Reynolds numbers. 5. Based on other kinematic and dynamic similarities, which are shown to exist between the two systems, a hypothetical mechanical exemplar of the mucociliary system is derived.

A Biomimetic Elastic Cable Driven Quadruped Robot: The RoboCat

2011 ◽  
Author(s):  
Elvedin Kljuno ◽  
J. Jim Zhu ◽  
Robert L. Williams ◽  
Stephen M. Reilly
Keyword(s):  
Kinetic Energy ◽  
Quadruped Robot ◽  
Effective Control ◽  
Kinematics And Dynamics ◽  
Dynamics Analysis ◽  
Bipedal Robots ◽  
Analysis And Design ◽  
And Control ◽  
Ground Impact ◽  
Transfer Potential

State of the art legged robots, such as the Honda’s series of bipedal robots ending in the latest advanced walking robot ASIMO, and the series of bipedal robots of Waseda University including the latest advanced robot WABIAN, employ joint-mount motors, which simplifies the analysis/design and traces the route for an effective control system, but results in legs that are heavy and bulky. Cable-driven robots overcome this shortcoming by allowing the motors to be mounted on or near the torso, thereby reducing the weight and inertia of the legs, resulting in lower overall weight and power consumption. To facilitate analysis and design, typical cable-driven robots use non-stretchable cables, which require at least n+1 motors for an n Degree-of-Freedom (DoF) joint. Therefore, for a robot with N joints, at least N additional motors are needed comparing to joint-mount motor drives. Moreover, the drive train of both joint-mount and cable-driven designs are rigid, which cannot effectively absorb ground impact shocks nor transfer potential energy to kinetic energy and vice versa when the robot is in motion, as biologic animals do. In this paper we present the design and test of a cat-size quadruped robot called RoboCat, which employs stretchable elastic cable-driven joints as inspired by biological quadruped animals. Although it complicates kinematics and dynamics analysis and design, the elastic cables allow n motors to be used for an n-DoF joint, thereby eliminating N motors for a robot with N joints comparing to non-stretchable cables, further realizing the weight and power savings of the cable driven design. Moreover, the elastic cable driven joints not only effectively absorb ground contact shock, but also effectively transfer potential and kinetic energy during walking or running, thereby improving the robot motion performance and energy efficiency. In the paper we will discuss the kinematics and dynamics analysis of elastic cable driven joints, implementation of elastic cable-driven joints on the Ohio University RoboCat, and control.

The orientation of multivalents at meiotic metaphase I: a workshop report

Genome ◽  
1987 ◽  
Vol 29 (4) ◽  
pp. 612-620 ◽  
Author(s):  
J. Sybenga ◽  
G. K. Rickards
Keyword(s):  
Data Collection ◽  
Key Words ◽  
Meiotic Metaphase ◽  
Workshop Report ◽  
Key Words Meiosis ◽  
Analytical Procedures ◽  
First Contact ◽  
Final Orientation ◽  
Metaphase I

During a workshop with 13 participants, several aspects of multivalent orientation at meiotic (pro)metaphase were discussed in an attempt to resolve some of the most prominent controversies with respect to terminology, interpretation of observations, and the validity of hypotheses and theories. For several terms and concepts, descriptive definitions were formulated that are recommended for general use. In the analysis of the behaviour of the multivalent in meiosis preprometaphase shape and position as important factors in final orientation were discussed, as well as the first contact between spindle and kinetochores and the role of reorientation. Specific characteristics of different multivalents and expected frequencies of different orientation types were considered. Finally, a few remarks on data collection and analytical procedures were made Key words: meiosis, multivalents, orientation, workshop.

scholarly journals Dynamics of a flexible body: a two-field formulation

2021 ◽  
Author(s):  
Michel Géradin
Keyword(s):  
Kinetic Energy ◽  
Elastic Deformation ◽  
Shape Function ◽  
Flexible Multibody Dynamics ◽  
Finite Element Discretization ◽  
Element Discretization ◽  
Motion Equations ◽  
Essential Condition ◽  
Relative Kinetic ◽  
Gyroscopic Forces

AbstractA two-field formulation of the nonlinear dynamics of an elastic body is presented in which positions/orientations and the resulting velocity field are treated as independent. Combining a nonclassical description of elastic velocity that includes the convection velocity due to elastic deformation with floating reference axes minimizing the relative kinetic energy due to elastic deformation provides a fully uncoupled expression of kinetic energy. A transformation inspired by the classical Legendre transformation concept is introduced to develop the motion equations in canonical form. Finite element discretization is achieved using the same shape function sets for elastic displacements and velocities. Specific attention is brought to the discretization of the gyroscopic forces induced by elastic deformation. A model reduction strategy to construct superelement models suitable for flexible multibody dynamics applications is proposed, which fulfills the essential condition of orthogonality between a rigid body and elastic motions. The problem of expressing kinematic connections at superelement boundaries is briefly addressed. Two academic examples have been developed to illustrate some of the concepts presented.

scholarly journals Dinamika Hukum Akad Nikah Via Teleconference Di Indonesia

2020 ◽  
Vol 10 (2) ◽  
pp. 107-118
Author(s):  
Muhammad Alwi Al-Maliki ◽  
Asep Saepudin Jahar
Keyword(s):  
Key Words ◽  
Literature Search ◽  
Abstract Word ◽  
Web Page ◽  
Scholarly Journals ◽  
Abstracting And Indexing ◽  
First Contact

An abstract is a brief, comprehensive summary of the contents of the article; it allows readers to survey the contents of an article quickly and, like a title, it enables persons interested in the document to retrieve it from abstracting and indexing databases. Most scholarly journals require an abstract. Consult the instructions to authors or web page of the journal to which you plan to submit your article for any journal-specific instructions. A well-prepared abstract can be the most important single paragraph in an article. Most people have their first contact with an article by seeing just the abstract, usually in comparison with several other abstracts, as they are doing a literature search. Readers frequently decide on the basis of the abstract whether to read the entire article. The abstract needs to be dense with information. By embedding key words in your abstract, you enhance the user's ability to find it. Do not exceed the abstract word limit of the journal to which you are submitting your article. Word limits vary from journal to journal and typically range from 100 to 150 words.

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