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Observer-based adaptive sliding mode fault-tolerant control for the underactuated space robot with joint actuator gain faults

Ronghua Lei, Li Chen (2021)

Kybernetika

An adaptive sliding mode fault-tolerant controller based on fault observer is proposed for the space robots with joint actuator gain faults. Firstly, the dynamic model of the underactuated space robot is deduced combining conservation law of linear momentum with Lagrange method. Then, the dynamic model of the manipulator joints is obtained by using the mathematical operation of the block matrices, hence the measurement of the angular acceleration of the base attitude can be omitted. Subsequently,...

OCA and towers in 𝒫 ( ℕ ) / f i n

Ilijas Farah (1996)

Commentationes Mathematicae Universitatis Carolinae

We shall show that Open Coloring Axiom has different influence on the algebra 𝒫 ( ℕ ) / f i n than on ℕ ℕ / f i n . The tool used to accomplish this is forcing with a Suslin tree.

Oligomorphic transformation monoids and homomorphism-homogeneous structures

Dragan Mašulović, Maja Pech (2011)

Fundamenta Mathematicae

A structure is called homomorphism-homogeneous if every homomorphism between finitely generated substructures of the structure extends to an endomorphism of the structure (P. J. Cameron and J. Nešetřil, 2006). In this paper we introduce oligomorphic transformation monoids in full analogy to oligomorphic permutation groups and use this notion to propose a solution to a problem, posed by Cameron and Nešetřil in 2006, to characterize endomorphism monoids of homomorphism-homogeneous relational structures...

O-minimal fields with standard part map

Jana Maříková (2010)

Fundamenta Mathematicae

Let R be an o-minimal field and V a proper convex subring with residue field k and standard part (residue) map st: V → k. Let k i n d be the expansion of k by the standard parts of the definable relations in R. We investigate the definable sets in k i n d and conditions on (R,V) which imply o-minimality of k i n d . We also show that if R is ω-saturated and V is the convex hull of ℚ in R, then the sets definable in k i n d are exactly the standard parts of the sets definable in (R,V).

O-minimal version of Whitney's extension theorem

Krzysztof Kurdyka, Wiesław Pawłucki (2014)

Studia Mathematica

This is a generalized and improved version of our earlier article [Studia Math. 124 (1997)] on the Whitney extension theorem for subanalytic p -Whitney fields (with p finite). In this new version we consider Whitney fields definable in an arbitrary o-minimal structure on any real closed field R and obtain an extension which is a p -function definable in the same o-minimal structure. The Whitney fields that we consider are defined on any locally closed definable subset of Rⁿ. In such a way, a local...

On 0 - 1 measure for projectors

Václav Alda (1980)

Aplikace matematiky

An example of a finite set of projectors in E 3 is exhibited for which no 0-1 measure exists.

On a Certain Notion of Finite and a Finiteness Class in Set Theory without Choice

Horst Herrlich, Paul Howard, Eleftherios Tachtsis (2015)

Bulletin of the Polish Academy of Sciences. Mathematics

We study the deductive strength of properties under basic set-theoretical operations of the subclass E-Fin of the Dedekind finite sets in set theory without the Axiom of Choice ( AC ), which consists of all E-finite sets, where a set X is called E-finite if for no proper subset Y of X is there a surjection f:Y → X.

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