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Geometrically controlled snake-like robot model
Shehadeh, Mhd Ali ; Návrat, Aleš (referee) ; Vašík, Petr (advisor)
This master’s thesis describes equations of motion for dynamic model of nonholonomic constrained system, namely the trident robotic snakes. The model is studied in the form of Lagrange's equations and D’Alembert’s principle is applied. Actually this thesis is a continuation of the study going at VUT about the simulations of non-holonomic mechanisms, specifically robotic snakes. The kinematics model was well-examined in the work of of Byrtus, Roman and Vechetová, Jana. So here we provide equations of motion and address the motion planning problem regarding dynamics of the trident snake equipped with active joints through basic examples and propose a feedback linearization algorithm.
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Identification of 3D objects for Robotic Applications
Hujňák, Jaroslav ; Návrat, Aleš (referee) ; Matoušek, Radomil (advisor)
This thesis focuses on robotic 3D vision for application in Bin Picking. The new method based on Conformal Geometric Algebra (CGA) is proposed and tested for identification of spheres in Pointclouds created with 3D scanner. The speed, precision and scalability of this method is compared to traditional descriptors based method. It is proved that CGA maintains the same precision as the traditional method in much shorter time. The CGA based approach seems promising for the use in the future of robotic 3D vision for identification and localization of spheres.
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Nonholonomic mechanisms geometry
Bartoňová, Ludmila ; Návrat, Aleš (referee) ; Vašík, Petr (advisor)
Tato diplomová práce se zabývá popisem kinematického modelu řízení neholonomního mechanismu, konkrétně robotického hada. Model je zkoumán prostředky diferenciální geometrie. Dále je odvozena jeho nilpotentní aproximace. Lokální říditelnost je zjištěna pomocí dimenze Lieovy algebry generované řídícími vektorovými poli a jejich Lieovými závorkami. V závěru jsou navrženy dva jednoduché řídící algoritmy, jeden pro globální a druhý pro lokální řízení, a poté následuje srovnání jednotlivých modelů.
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Geometric control of a snake-like robot
Jašek, Dominik ; Hrdina, Jaroslav (referee) ; Návrat, Aleš (advisor)
This thesis deals with the nonholonomic mechanics, description of nonholonomic constraints and the control algorithms. In particular it focuses on snake with 4 links. From kinematic equations we derive elementary vector fields, later four more are added thanks to Lie bracket. Using these vector fields we are able to devise an algorithm for controling the snake. Furthermore, the thesis also includes a serpenoid input applicated in the simulation enviroment V-REP.
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3D scene reconstruction using Clifford algebras
Hrubý, Jan ; Návrat, Aleš (referee) ; Hrdina, Jaroslav (advisor)
Tato diplomová práce má za cíl seznámit čtenáře se stále ještě relativně novou a neznámou oblastí matematiky, s geometrickou algebrou. Nejdříve jsou uvedeny základní definice a poté jsou studovány vlastnosti obecné geometrické algebry. Další velká část textu se věnuje Konformní geometrické algebře, která je v současnosti jedna z nejvíce zkoumaných a aplikovaných geometrických algeber. Jsou popsány její algebraické a geometrické vlastnosti, konkrétně schopnost reprezentovat určité geometrické objekty jako vektory. Taktéž umožňuje počítat jejich průniky a konformní transformace. Další část textu je zaměřena na aplikace Konformní geometrické algebry, nejdříve k popisu kinematiky robotické ruky a poté v binokulárním viděni.
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Algebra of dual quaternions in image analysis
Hrubý, Jan ; Návrat, Aleš (referee) ; Hrdina, Jaroslav (advisor)
This work has two goals. Firstly it is to acquaint the reader with the classical use of quaternions and dual quaternions in geometry. Secondly the generalization of the Fourier transform into the set of dual quaternions. At first it goes into algebraic properties and structure of quaternions and ways of their inscriptions. Later dual numbers are introduced and consecutively with their help dual quaternions. Then the work deals with description of rotations and translations using quaternions and dual quaternions, that enable their easy description. Finally the discreet dual quaternion Fourier transform is defined, and for its effective calculation the algorithm is derived, which is then brought into effect as a code in program environment MATLAB.
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Control Theory of robotic snakes with more than three links
Tejkal, Martin ; Návrat, Aleš (referee) ; Hrdina, Jaroslav (advisor)
The subject of this Bachelor's thesis is control theory of mechanism that simulates snake's movement. From a viewpoint of control theory the robot is classified as nonholonomic system, controllability of which is determined by vector fields. Based on nonholomic constrain a set of input vector fields is obtained from a system of nonholonomic equations. The other vector fields that are necessary for controllability of the system are derived from the set of input vector fields by application of Lie bracket operation on two input fields. This set of vector fields is further analysed in particular points of the configuration space. Finally we discuss changes that need to be done in order to describe a mechanism created by adding one, or more new links.
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Dynamics of Snake Robots
Kubiena, Jaromír ; Doupovec, Miroslav (referee) ; Návrat, Aleš (advisor)
In this thesis, we deal with the mathematical description of the kinematics and the dynamics of mechanical systems. Then we focus on the particular mechanical system which is the Square robot with four legs with active joints and passive wheels, which moves on horizontal plane. The kinematics of the mechanical system is described by the control matrix, then we use it to express the equations of motion. We compute the dynamics the robot by using Lagrange equations. We verify that the mechanical system is nonholonomic constrained and we verify controllability by using Lie bracket and distribution. We find the singular postures of the robot.
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