scholarly journals Importance and Effectiveness of Representing the Shapes of Cosserat Rods and Framed Curves as Paths in the Special Euclidean Algebra

2017 ◽  
Vol 132 (1) ◽  
pp. 43-65 ◽  
Author(s):  
Giulio G. Giusteri ◽  
Eliot Fried
Author(s):  
Vincent Aloi ◽  
Caroline Black ◽  
Caleb Rucker

Parallel continuum robots can provide compact, compliant manipulation of tools in robotic surgery and larger-scale human robot interaction. In this paper we address stiffness control of parallel continuum robots using a general nonlinear kinetostatic modeling framework based on Cosserat rods. We use a model formulation that estimates the applied end-effector force and pose using actuator force measurements. An integral control approach then modifies the commanded target position based on the desired stiffness behavior and the estimated force and position. We then use low-level position control of the actuators to achieve the modified target position. Experimental results show that after calibration of a single model parameter, the proposed approach achieves accurate stiffness control in various directions and poses.


2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Thorsten Fütterer ◽  
Axel Klar ◽  
Raimund Wegener

A numerical method for special Cosserat rods based on Antman's description Antman, 2005 is developed for hyperelastic materials and potential forces. This method preserves the relevant properties of the underlying PDE system, namely, the orthonormality of the directors and the conservation of the energy.


2019 ◽  
Vol 14 ◽  
pp. 71
Author(s):  
Dennis Bonatsos ◽  
D. Lenis ◽  
D. Petrellis ◽  
P. Terziev ◽  
I. Yigitoglu

A γ-rigid solution of the Bohr Hamiltonian for 7 = 30° is derived, its ground state band being related to the second order Casimir operator of the Euclidean algebra E(4). Parameter-free (up to overall scale factors) predictions for spectra and B(E2) transition rates are in close agreement to the E (5) critical point symmetry, as well as to experimental data in the Xe region around A = 130.


2008 ◽  
Vol DMTCS Proceedings vol. AJ,... (Proceedings) ◽  
Author(s):  
Alistair Savage

International audience We show that the category of representations of the Euclidean group $E(2)$ is equivalent to the category of representations of the preprojective algebra of the quiver of type $A_{\infty}$. Furthermore, we consider the moduli space of $E(2)$-modules along with a set of generators. We show that these moduli spaces are quiver varieties of the type considered by Nakajima. These identifications allow us to draw on known results about preprojective algebras and quiver varieties to prove various statements about representations of $E(2)$. In particular, we show that $E(2)$ has wild representation type but that if we impose certain combinatorial restrictions on the weight decompositions of a representation, we obtain only a finite number of indecomposable representations. Nous montrons que la catégorie des représentations du groupe d'Euclide $E(2)$ est équivalente à la catégorie des représentations de l'algèbre préprojective de type $A_{\infty}$. De plus, nous considérons l'espace classifiant de modules de $E(2)$ avec un ensemble de générateurs. Nous montrons que ces espaces sont de variétés de carquois de Nakajima. Cette identification nous permet d'utiliser des résultats des algèbres préprojectives et des variétés de carquois pour prouver des affirmations sur des représentations de $E(2)$. En particulier, nous montrons que le type de représentations de $E(2)$ est sauvage mais si nous imposons des restrictions aux poids d'une représentation, il y a seulement un nombre fini de représentations qui ne sont pas décomposables.


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