Browsing by Author "Sahiner, B"

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    ON THE CURVATURE THEORY OF NON-NULL CYLINDRICAL SURFACES IN MINKOWSKI 3-SPACE
    Sahiner, B; Kazaz, M; Ugurlu, HH
    This paper presents the curvature theory of non-null cylindrical surfaces in Minkowski 3-space. The definition of the line of striction and generator trihedron for cylindrical surfaces in Minkowski 3-space are given. The derivation formulae and Darboux instantaneous rotation vectors of generator trihedrons which play important role in robot kinematics are found. Moreover, curvature theory of a Lorentzian circular cylinder is given as an example.
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    Direction curves of tangent indicatrix of a curve
    Sahiner, B
    In this paper, we define some new associated curves as integral curves of a vector field generated by Frenet vectors of tangent indicatrix of a curve in Euclidean 3-space. We give some relationships between curvatures of these curves. By using these associated curves, we give some methods to construct helices and slant helices from some special spherical curves such as circles on unit sphere, spherical helices, and spherical slant helices. Finally, we give some related examples. (C) 2018 Elsevier Inc. All rights reserved.
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    Quaternionic Direction Curves
    Sahiner, B
    In this paper, we define new quaternionic associated curves called quaternionic principal-direction curves and quaternionic principal-donor curves. We give some properties and relationships between Frenet vectors and curvatures of these curves. For spatial quaternionic curves, we give characterizations for quaternionic helices and quaternionic slant helices by means of their associated curves.
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    Relations between a dual unit vector and Frenet vectors of a dual curve
    Sahiner, B; Önder, M
    In this paper, we generalize the notions of helix and slant helix in dual space in a more general case such as the dual angle between a fixed dual unit vector and Frenet vectors of a dual curve is not constant. We study the motions of the lines corresponding to dual Frenet vectors and dual Frenet instantaneous rotation vector with respect to a fixed line. We obtain some characterizations for such dual curves and show that these characterizations include the definitions and characterizations of dual helix and dual slant helix in some special cases.
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    A Study on Motion of a Robot End-Effector Using the Curvature Theory of Dual Unit Hyperbolic Spherical Curves
    Sahiner, B; Kazaz, M; Ugurlu, HH
    In this paper we study the motion of a robot end-effector by using the curvature theory of a dual unit hyperbolic spherical curve which corresponds to a timelike ruled surface with timelike ruling generated by a line fixed in the end-effector. In this way, the linear and angular differential properties of the motion of a robot end-effector such as velocities and accelerations which are important information in robot trajectory planning are determined. Moreover, the motion of a robot end-effector which moves on the surface of a right circular hyperboloid of one sheet is examined as a practical example.