A Lagrangian Dynamic Model for Soft Cylindrical Robots Without Internal Holonomic Constraint

2021 ◽  
Author(s):  
Christian-Alejandro Trejo-Ramos ◽  
Ernesto Olguin-Diaz ◽  
Vicente Parra-Vega ◽  
Carlos-Ernesto Vazquez-Garcia
Keyword(s):  
Dynamic Model ◽  
Holonomic Constraint ◽  
Lagrangian Dynamic

Dynamic Parameters and Friction Model Identification of an Industrial Hybrid Robot

2019 ◽  
Author(s):  
Binbin Zhang ◽  
Liping Wang ◽  
Jun Wu
Keyword(s):  
Dynamic Model ◽  
Control Method ◽  
Driving Forces ◽  
Dynamic Control ◽  
Model Identification ◽  
Friction Model ◽  
Dynamic Parameters ◽  
Typical Trajectory ◽  
Lagrangian Dynamic ◽  
Moving Speed

Abstract To obtain higher performance for an industrial hybrid robot, the dynamic control method is utilized to control the robot. For dynamic control, the control performance is directly affected by the accuracy of the dynamic model. This paper investigated a method to establish and identify an accurate dynamic model. First, based on the Lagrangian dynamic equation and the Stribeck friction model, the unidentified dynamic model of the five-DOF hybrid robot is established. Second, identification experiments are carried out. Each of the driving joints performs frequent reciprocating motions individually. In the meantime, the moving speed is gradually increased to obtain driving torques of the respective joint at different moving speeds. Then the dynamic parameters with lower coupling are identified by using the standard deviation index and the least squares methods until all parameters are gradually determined. Finally, the hybrid robot moves a typical trajectory, while the currents of each joint are collected to obtain the driving forces. The actual driving forces, the identified dynamic model, and the unidentified dynamic model are compared. The results show that the identified method could significantly improve the accuracy of the dynamic model. The method proposed in this paper is general and can be applied to the other robots without adding any sensors.

Short-term volume and turgor regulation in yeast

2008 ◽  
Vol 45 ◽  
pp. 147-160 ◽  
Author(s):  
Jörg Schaber ◽  
Edda Klipp
Keyword(s):  
Dynamic Model ◽  
Volume Change ◽  
Volume Regulation ◽  
Time Course ◽  
Osmotic Shock ◽  
Intracellular Concentration ◽  
Short Term ◽  
Hydrodynamic Property ◽  
Turgor Regulation ◽  
Thermodynamic Framework

Volume is a highly regulated property of cells, because it critically affects intracellular concentration. In the present chapter, we focus on the short-term volume regulation in yeast as a consequence of a shift in extracellular osmotic conditions. We review a basic thermodynamic framework to model volume and solute flows. In addition, we try to select a model for turgor, which is an important hydrodynamic property, especially in walled cells. Finally, we demonstrate the validity of the presented approach by fitting the dynamic model to a time course of volume change upon osmotic shock in yeast.

THE STATISTICAL GEOMETRY OF THE STRUCTURE OF THE MOLECULAR DYNAMIC MODEL OF LIQUID AND AMORPHOUS ALUMINIUM

1980 ◽  
Vol 41 (C8) ◽  
pp. C8-284-C8-288 ◽  
Author(s):  
V. A. Poluchin ◽  
M. M. Dzugutov ◽  
V. F. Uchov ◽  
R. A. Vatolin
Keyword(s):  
Molecular Dynamic ◽  
Dynamic Model ◽  
Statistical Geometry ◽  
Molecular Dynamic Model

Study of the dynamics of ТПА 350 automatic mill working stand elements

2020 ◽  
Vol 76 (8) ◽  
pp. 830-840
Author(s):  
S. R. Rakhmanov ◽  
V. V. Povorotnii
Keyword(s):  
Mechanical System ◽  
Dynamic Model ◽  
Maximum Amplitude ◽  
Calculation Scheme ◽  
Dynamic Loads ◽  
Forced Oscillations ◽  
Mass Model ◽  
Automatic Mill ◽  
Hollow Billet ◽  
Oscillation Movement

To form a necessary geometry of a hollow billet to be rolled at a pipe rolling line, stable dynamics of the base equipment of the automatic mill working stand has a practical meaning. Among the forces, acting on its parts and elements, significant by value short-time dynamic loads are the least studied phenomena. These dynamic loads arise during transient interaction of the hollow billet, rollers, mandrel and other mill parts at the forced grip of the hollow billet. Basing of the calculation scheme and dynamic model of the mechanical system of the ТПА 350 automatic mill working stand was accomplished. A mathematical model of dynamics of the system “hollow billet (pipe) – working stand” within accepted calculation scheme and dynamic model of the mechanical system elaborated. Influence of technological load of the rolled hollow billet variation in time was accounted, as well as variation of the mechanical system mass, and rigidity of the ТПА 350 automatic mill working stand. Differential equations of oscillation movement for four-mass model of forked sub-systems of the automatic mill working stand were made up, results of their digital calculation quoted. Dynamic displacement of the stand elements in the inter-roller gap obtained, which enabled to estimate the results of amplitude and frequency characteristics of the branches of the mill rollers setting. It was defined by calculation, that the maximum amplitude of the forced oscillations of elements of the ТПА 350 automatic mill working stand within the inter-roller gap does not exceed 2 mm. It is much higher than the accepted value of adjusting parameters of the deformation center of the ТПА 350 automatic mill. A scheme of comprehensive modernization of the rollers setting in the ТПА 350 automatic mill working stand was proposed. It was shown, that increase of rigidity of rollers setting in the ТПА 350 automatic mill working stand enables to stabilize the amplitude of forced oscillations of the working stand elements within the inter-rollers gap and considerably decrease the induced nonuniform hollow billet wall thickness and increase quality of the rolled pipes at ТПА 350.

J. Tobin's Monetary Dynamic Model and the Analysis of Russian Economy

2009 ◽  
pp. 70-93
Author(s):  
V. Manevich
Keyword(s):  
Dynamic Model ◽  
Economic Thought ◽  
Financial Policies ◽  
Russian Economy ◽  
Q Theory ◽  
Keynesian Economic ◽  
The Relationship ◽  
Monetary Assets

The paper considers the monetary dynamic model developed by J. Tobin, the leader of Keynesian economic thought in 1970-1990. Particularly, the author examines q-theory of investment proposed by Tobin which allows to expose the relationship between supply of monetary assets and investment in real capital. Application of various tools of monetary and financial policies is also considered in its different forms. The author aspires to use Tobin's model for the analysis of processes existing in the Russian economy and to test theoretical propositions and relationships elaborated by Tobin on Russian statistics.

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