Search for dissertations about: "quaternion"

Showing result 1 - 5 of 11 swedish dissertations containing the word quaternion.

2. 1. Part Quality Prediction and Variation Reduction in Multistage Machining Processes Based on Skin Model Shapes

   Author : Filmon Yacob; Daniel Semere; Sophie Gröger; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Machining simulation; model-based prediction; variation propagation; variation source identification; variation compensation; tolerance analysis; Octree; anomaly detection; quaternion; dual quaternion; Plücker coordinate.; Maskinbearbetningssimulering; modellbaseradförutsägelse; variationsspridning; variationskällidentifiering; variationskompensation; toleransanalys; Octree; dual quaternions; Plücker-koordinat.; Production Engineering; Industriell produktion;

   Abstract : All manufacturing processes inevitably induce variations into manufactured parts that may result in nonconformance. Nonconforming parts incur costs due to the additional process required for rework or scrap loss. Hence, methodical efforts to reduce these variations are necessary for competitive manufacturing. READ MORE

4. 2. Quaternion Orders and Ternary Quadratic Forms Orders of Class Number One and Representations of Algebraic Integers by Quadratic Forms

   Author : Elise Björkholdt; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; quaternion order; ternary quadratic form; class number; even Clifford algebra; quaternion algebra; embedding number; 11E12; 16H05; 11E20; 11E25; 11E88; even Clifford algebra;

   Abstract : Let R be the ring of integers in a totally real quadratic field K. The purpose of the thesis is to study totally definite quaternion R-orders and representations of elements in R by totally positive definite integral ternary quadratic forms. The thesis consists of three papers. READ MORE

5. 3. Towards Aerial Robotic Workers

   Author : Emil Fresk; Dimos Dimarogonas; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aerial Robotic Worker; UAV; Multirotor; Quadrotor; Estimation; Quaternion; Inertial Navigation; Reglerteknik; Control Engineering;

   Abstract : The aim of this thesis is to advance the control and estimation schemes for multirotors, and more specifically the Aerial Robotic Worker, in order to progress towards the necessary control and estimation performance for robust control, cooperation and collaboration. Towards this envisioned aim, this Licentiate thesis will present the following main research contributions: a) a singularity-free attitude controller for the attitude problem has been established, that does not have the inherent drawbacks of Euler angle or Direction Cosine Matrix based approaches, b) a generalized estimation scheme for attitude, position and parameter estimation will be presented that has the merit of low computational footprint, while it is robust towards magnetic disturbances and able to identify key parameters in the model of an Aerial Robotic Worker, c) an method for estimating the induced vibration frequencies on the multirotor’s frame, and the respective amplitudes, that relies on notch filtering for attenuating the induced vibrations, and d) a theoretical establishment, as well as an experimental development and evaluation of a variable pitch propeller model to add additional degrees of freedom and increase the robustness of an Aerial Robotic Worker. READ MORE

6. 4. Ghosts and machines : regularized variational methods for interactive simulations of multibodies with dry frictional contacts

   Author : Claude Lacoursière; Bo Kåggström; Ander Klarbring; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Discrete mechanics; Variational method; Contact problems; Impacts; Least action principle; Saddle point problems; Lagrange Multipliers; Constrained systems; Multibody Systems; Numerical regularization; Constraint realization; Constraint stabilization; Dry friction; Differential Algebraic Equations; Nonsmooth problems; Linear Complementarity; Quaternion algebra; Numerical linear algebra; Physics modeling; Interactive simulation; Numerical stability; Rigid body dynamics; Dissipative systems; Computational physics; Beräkningsfysik;

   Abstract : A time-discrete formulation of the variational principle of mechanics is used to provide a consistent theoretical framework for the construction and analysis of low order integration methods. These are applied to mechanical systems subject to mixed constraints and dry frictional contacts and impacts---machines. READ MORE

7. 5. Ternary quadratic forms over algebraic integers

   Author : Elise Björkholdt; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; ternary quadratic form; quaternion order; even Clifford algebra; quaternation algebra; embedding number; quaternion order;

   Abstract : .... READ MORE