Reinforcement Learning Approach for Autonomous UAV Navigation in 3D Space

In the last two decades, the rapid development of unmanned aerial vehicles (UAVs) resulted in their usage for a wide range of applications. Miniaturization and cost reduction of electrical components have led to their commercialization, and today they can be utilized for various tasks in an unknown environment. Finding the optimal path based on the start and target pose information is one of the most complex demands for any intelligent UAV system. As this problem requires a high level of adaptability and learning capability of the UAV, the framework based on reinforcement learning is proposed for the localization and navigation tasks. In this paper, Q-learning algorithm for the autonomous navigation of the UAV in 3D space is implemented. To test the proposed methodology for UAV intelligent control, the simulation is conducted in ROS-Gazebo environment. The obtained simulation results have shown that the UAV can reach the target pose autonomously in an efficient way

Reinforcement Learning Approach for Autonomous UAV Navigation in 3D Space

In the last two decades, the rapid development of unmanned aerial vehicles (UAVs) resulted in their usage for a wide range of applications. Miniaturization and cost reduction of electrical components have led to their commercialization, and today they can be utilized for various tasks in an unknown environment. Finding the optimal path based on the start and target pose information is one of the most complex demands for any intelligent UAV system. As this problem requires a high level of adaptability and learning capability of the UAV, the framework based on reinforcement learning is proposed for the localization and navigation tasks. In this paper, Q-learning algorithm for the autonomous navigation of the UAV in 3D space is implemented. To test the proposed methodology for UAV intelligent control, the simulation is conducted in ROS-Gazebo environment. The obtained simulation results have shown that the UAV can reach the target pose autonomously in an efficient way

Micro/Nano Structures and Systems

Micro/Nano Structures and Systems: Analysis, Design, Manufacturing, and Reliability is a comprehensive guide that explores the various aspects of micro- and nanostructures and systems. From analysis and design to manufacturing and reliability, this reprint provides a thorough understanding of the latest methods and techniques used in the field. With an emphasis on modern computational and analytical methods and their integration with experimental techniques, this reprint is an invaluable resource for researchers and engineers working in the field of micro- and nanosystems, including micromachines, additive manufacturing at the microscale, micro/nano-electromechanical systems, and more. Written by leading experts in the field, this reprint offers a complete understanding of the physical and mechanical behavior of micro- and nanostructures, making it an essential reference for professionals in this field

Principles and Characteristics of Different EDM Processes in Machining Tool and Die Steels

Electric discharge machining (EDM) is one of the most efficient manufacturing technologies used in highly accurate processing of all electrically conductive materials irrespective of their mechanical properties. It is a non-contact thermal energy process applied to a wide range of applications, such as in the aerospace, automotive, tools, molds and dies, and surgical implements, especially for the hard-to-cut materials with simple or complex shapes and geometries. Applications to molds, tools, and dies are among the large-scale initial applications of this process. Machining these items is especially difficult as they are made of hard-to-machine materials, they have very complex shapes of high accuracy, and their surface characteristics are sensitive to machining conditions. The review of this kind with an emphasis on tool and die materials is extremely useful to relevant professions, practitioners, and researchers. This review provides an overview of the studies related to EDM with regard to selection of the process, material, and operating parameters, the effect on responses, various process variants, and new techniques adopted to enhance process performance. This paper reviews research studies on the EDM of different grades of tool steel materials. This article (i) pans out the reported literature in a modular manner with a focus on experimental and theoretical studies aimed at improving process performance, including material removal rate, surface quality, and tool wear rate, among others, (ii) examines evaluation models and techniques used to determine process conditions, and (iii) discusses the developments in EDM and outlines the trends for future research. The conclusion section of the article carves out precise highlights and gaps from each section, thus making the article easy to navigate and extremely useful to the related research communit

Control methodology and modelling of active fixtures

Fixtures are used to fixate, position and support workpieces, and are critical elements in manufacturing processes. Machining is one of these manufacturing processes, and this is often done by computer numerical control (CNC) machines. A major trend observed in production industry is that manufacturing is increasingly done in small batches in combination with a quick changeover from one product to another, in combination with a surge in automation. Several novel fixture concepts have been developed that allow for a reconfiguration of the fixture layout, such that different types of workpieces can be fixtured using the same fixture components. However, the initial novel fixturing concepts lacked accuracy, and, in addition, required long set-up times. Recently, a new fixturing concept has been developed, the so-called intelligent fixturing system. Sensors and actuators are integrated in an intelligent fixturing system, which allows for an automatic and precise reconfiguration of the fixturing elements. Additionally, the actuated fixture elements can be used to exert optimal clamping forces to minimise the workpiece deflection during the machining process, this is called active fixturing. A literature survey has been carried out, in which it has been established that the main process variables to control in active fixturing, are the reaction forces at the contacts where the workpiece is fixated and supported by the fixture (the locating points), and/or the part or fixture displacements. Furthermore, four knowledge gaps were identified: (1) a lack of computationally efficient models of workpiece response during machining; (2) a lack of methodic structural analysis approach of part-fixture interaction; (3) a lack of model-based control design, which can potentially speed up the fixture design process; and (4) a lack of control design methodology for active fixturing systems. An active fixturing system can be divided into the following subsystems: the part, the part-fixture contact interface, passive fixture elements, the actuated clamp, sensors and the controller(s). In the thesis, a methodical research approach has been applied to address the knowledge gaps by analysing the active fixturing subsystems. In addition, a model-based control design methodology has been proposed. The research has aimed to establish mathematical models, or the necessary tools and methodology to build the subsystem models, and methods to connect the subsystem models into an overall model of the active fixturing system. On basis of the subsystem analyses, two simple, yet complete, active fixturing systems have been modelled. Parameter studies have been held to assess the performance of the control design. In addition, an industrial case study has been analysed, using the developed control design methodology. The study of the subsystems resulted in the comprehensive structural dynamic analysis of workpieces: a finite element model of the workpiece is built. Typically, finite element models contain too many degrees of freedom for real-time control applications. It was found that model reduction techniques can be used to reduce significantly the number of degrees of freedom. Methodologies for the selection of the degrees of freedom and for ensuring that the model reduction is accurate enough for practical use have been established. Mathematical models for hydraulically and electromechanically actuated clamps have been established. Compensators for closed-loop servo-control of the clamps have been investigated and control strategies to maintain workholding stability are found. Finally, a methodology to establish the overall model of an active fixturing system has been implemented. The control design methodology, and the mathematical tools established in the thesis have been verified against case studies of simple active fixturing systems. Furthermore, from the industrial case study it is concluded that the control design methodology can be successfully applied on complex fixturing systems. Additionally, a mathematical model for a piezoelectrically actuated clamp was derived, which also demonstrates the general applicability of the control design methodology derived here, as a new established actuator model is integrated in the control design. The overall conclusion, is hence that a good methodology for the model-based control design of active part-fixturing systems has been developed, which enables the engineer to speed up the design process of active fixturing systems

Proceeding Of Mechanical Engineering Research Day 2015 (MERD’15)

This Open Access e-Proceeding contains 74 selected papers from the Mechanical Engineering Research Day 2015 (MERD’15) event, which is held in Kampus Teknologi, Universiti Teknikal Malaysia Melaka (UTeM) - Melaka, Malaysia, on 31 March 2015. The theme chosen for this event is ‘Pioneering Future Discovery’. The response for MERD’15 is overwhelming as the technical committees have received more than 90 papers from various areas of mechanical engineering. From the total number of submissions, the technical committees have selected 74 papers to be included in this proceeding. The selected papers are grouped into 12 categories: Advanced Materials Processing; Automotive Engineering; Computational Modeling and Analysis & CAD/CAE; Energy Management & Fuels and Lubricants; Hydraulics and Pneumatics & Mechanical Control; Mechanical Design and Optimization; Noise, Vibration and Harshness; Non-Destructive Testing & Structural Mechanics; Surface Engineering and Coatings; Others Related Topic. With the large number of submissions from the researchers in other faculties, the event has achieved its main objective which is to bring together educators, researchers and practitioners to share their findings and perhaps sustaining the research culture in the university. The topics of MERD’15 are based on a combination of advanced research methodologies, application technologies and review approaches. As the editor-in-chief, we would like to express our gratitude to the editorial board members for their tireless effort in compiling and reviewing the selected papers for this proceeding. We would also like to extend our great appreciation to the members of the Publication Committee and Secretariat for their excellent cooperation in preparing the proceedings of MERD’15

Special Issue of the Manufacturing Engineering Society (MES)

This book derives from the Special Issue of the Manufacturing Engineering Society (MES) that was launched as a Special Issue of the journal Materials. The 48 contributions, published in this book, explore the evolution of traditional manufacturing models toward the new requirements of the Manufacturing Industry 4.0 and present cutting-edge advances in the field of Manufacturing Engineering focusing on additive manufacturing and 3D printing, advances and innovations in manufacturing processes, sustainable and green manufacturing, manufacturing systems (machines, equipment and tooling), metrology and quality in manufacturing, Industry 4.0, product lifecycle management (PLM) technologies, and production planning and risks

Cumulative index to NASA Tech Briefs, 1963-1967

Cumulative index to NASA survey on technology utilization of aerospace research outpu

NASA Tech Briefs, Spring 1983

Topics include: NASA TU Services: Technology Utilization services that can assist you in learning about and applying NASA technology. New Product Ideas: A summary of selected innovations of value to manufacturers for the development of new products; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Life Sciences; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences