Browsing by Author "Mlýnek, Jaroslav"
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- ItemDESIGN OF COMPOSITE FRAMES USED IN AGRICULTURAL MACHINERY(CZECH UNIVERSITY LIFE SCIENCES PRAGUE, DEPT SYSTEMS ENG, KAMYCKA 129, PRAGUE 6 165 21, CZECH REPUBLIC, 2019-01-01) Mlýnek, Jaroslav; Petrů, Michal; Martinec, TomášAt present, composite materials are increasingly used in agricultural machinery. The light weight, long lifespan and minimal maintenance of composites are among the main reasons for their use in agricultural machinery. Frame composites are often produced for the needs of agriculture. The production technology of these composites is based on the winding of fibres (from carbon or glass) on a frame (usually from polyurethane). A fibre processinghead and industrial robot are used in the production of composite frame. This paper describes the calculation of an appropriate off-line trajectory of the industrial robot during the passage of frame through the fibre-processing head. The described mathematical model of the winding process and matrix calculus are used to calculate suitable robot trajectory.
- ItemFabrication of High-Quality Polymer Composite Frame by a New Method of Fiber Winding Process(MDPI, 2020-05-02) Mlýnek, Jaroslav; Petrů, Michal; Martinec, Tomáš; Koloor, Seyed Saeid RahimianPolymer composite frame has been frequently used in the main structural body of vehicles in aerospace, automotive, etc., applications. Manufacturing of complex curved composite frame suffer from the lack of accurate and optimum method of winding process that lead to preparation of uniform fiber arrangement in critical location of the curved frame. This article deals with the fabrication of high-quality polymer composite frame through an optimal winding of textile fibers onto a non-bearing core frame using a fiber-processing head and an industrial robot. The number of winding layers of fibers and their winding angles are determined based on the operational load on the composite structure. Ensuring the correct winding angles and thus also the homogeneity of fibers in each winding layer can be achieved by using an industrial robot and by definition of its suitable off-line trajectory for the production cycle. Determination of an optimal off-line trajectory of the end-effector of a robot (robot-end-effector (REE)) is important especially in the case of complicated 3D shaped frames. The authors developed their own calculation procedure to determine the optimal REE trajectory in the composite manufacturing process. A mathematical model of the winding process, matrix calculus (particularly matrices of rotations and translations) and an optimization differential evolution algorithm are used during calculation of the optimal REE trajectory. Polymer composites with greater resistance to failure damage (especially against physical destruction) can be produced using the above mentioned procedure. The procedure was successfully tested in an experimental composite laboratory. Two practical examples of optimal trajectory calculation are included in the article. The described optimization algorithm of REE trajectory is completely independent of the industrial robot type and robot software tools used and can also be used in other composite manufacturing technologies.
- ItemMatematické modely vedení tepla v elektrických strojích(2007-01-01) Mlýnek, Jaroslav
- ItemOptimization of Industrial Robot Trajectory in Composite Production(IEEE, 345 E 47TH ST, NEW YORK, NY 10017 USA, 2018-01-01) Mlýnek, Jaroslav; Petrů, Michal; Martinec, TomášCurrently, traditional materials (e.g. iron, steel, aluminium alloy, wood) are increasingly being replaced by composites in many industrial areas. The main advantages of these new materials are their light weight, high strength and flexibility, corrosion resistance, long lifespan and the reduced price of the produced components. This article discusses the quality of the manufacturing process technology of a shaped composite in 3D space. The technology used is based on a winding of carbon filaments on a polyurethane frame with a circular cross-section (this type of composites is used, for example, in automotive chassis). One important factor in composite frame quality is making the correct winding angles of fibres on the frame and the homogeneity of the individual winding layers. The composite frame is attached to the end-effector of the robot and successively passes through the fibre-processing head during the winding process with three layers. Each layer of fibres is wound at a different angle (usually at pi/4, 0 and - pi/4). The mathematical model of the winding process and the matrix calculus (especially matrices of rotations, translates and calculations of Euler angles) are used to determine the optimized 3D trajectory of end-effector in this paper. The differential evolution algorithm is applied to finding the optimized 3D trajectory of the end-effector. In this way the winding angles and homogeneity of winding layers are maintained during production of the frame composite. The optimized end-effector trajectory is defined by calculated sequence of tool-centre-point values. The calculation of optimized trajectory is programmed and tested in the Delphi development environment. This approach to determining the optimized trajectory of the robot is substantially more effective than the repeated search of a suitable trajectory using the control panel (teach pendant) of the robot.
- ItemSoustavy lineárních algebraických rovnic(Technická Univerzita v Liberci, 2011-01-01) Hušková, Ivana; Mlýnek, JaroslavThis work is focused on solving systems of linear algebraic equations. The work is of historical reasons for addressing this issue. A basic overview of direct and iterative methods for solving systems of linear algebraic equations is given along with advantages of each method. A comprehensive overview of methods for solving systems allow students to easily grasp the issues. The remainder of the work discusses in more detail the conjugate gradient method and describes the basic properties and methods of its own algorithm programmed in Matlab language. Several numerical experiments were also carried out, using programmed conjugate gradient method. This method was used for the numerical solution of ordinary differential equations.