839 research outputs found

    Modelling and control of a 2-DOF planar parallel manipulator for semiconductor packaging systems

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    A novel direct-drive planar parallel manipulator for high-speed and high-precision semiconductor packaging systems is presented. High precision kinematics design, significant redaction on moving mass and driving power of the actuators over traditional XY motion stages are the benefits of the proposed manipulator. The mathematical model of the manipulator is obtained using the Newton-Enter method and a practical model-based control design approach is employed to design the PID computed-torque controller. Experimental results demonstrate that the proposed planar parallel manipulator has significant improvements on motion performance in terms of positioning accuracy, settling time and stability when compared with traditional XY stages. This shows that the proposed planar parallel manipulator can provide a superior alternative for replacing traditional XY motion stages in high precision low-payload applications. © 2005 IEEE.published_or_final_versio

    Advanced Strategies for Robot Manipulators

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    Amongst the robotic systems, robot manipulators have proven themselves to be of increasing importance and are widely adopted to substitute for human in repetitive and/or hazardous tasks. Modern manipulators are designed complicatedly and need to do more precise, crucial and critical tasks. So, the simple traditional control methods cannot be efficient, and advanced control strategies with considering special constraints are needed to establish. In spite of the fact that groundbreaking researches have been carried out in this realm until now, there are still many novel aspects which have to be explored

    Linear Dynamic Modeling of Parallel Kinematic Manipulators from Observable Kinematic Elements.

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    International audienceThis paper presents a linear method for kinematic and dynamic modeling of parallel kinematic manipulators. This method is simple, compact and clear. One can write all the equations from the beginning till the end with pen and paper. It is thus well suited to mechanical understanding and computer implementation. We can apply it to many parallel robots. This method relies on a body-oriented representation of observable rectilinear kinematic structures (kinematic elements) which form the robot legs

    Radial basis function neural network control for parallel spatial robot

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    The derivation of motion equations of constrained spatial multibody system is an important problem of dynamics and control of parallel robots. The paper firstly presents an overview of the calculating the torque of the driving stages of the parallel robots using Kronecker product. The main content of this paper is to derive the inverse dynamics controllers based on the radial basis function (RBF) neural network control law for parallel robot manipulators. Finally,  numerical simulation of the inverse dynamics controller for a 3-RRR delta robot manipulator is presented as an illustrative example

    OPTIMIZATION OF A FUZZY CONTROL DESIGN WITH RESPECT TO A PARALLEL MECHANISM WORKSPACE

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    Disertační práce je zaměřena na využití fuzzy logiky při návrhu řízení paralelního mechanismu založeného na Stewartově platformě. Hlavním cílem je navrhnout řídicí systém, který zabezpečí provádění biomedicínských experimentů. K tomuto účelu je nezbytné zařízení, které zajistí simulaci fyziologických pohybů lidského těla charakteristickým danému implantátu, včetně silového zatížení. Uzavřený kinematický řetězec paralelních manipulátorů výrazně zvyšuje tuhost mechanismu. Manipulátory s paralelní kinematickou strukturou dosahují lepší přesnosti a opakovatelnosti dosažení požadované polohy efektoru a mohou vyvozovat větší sílu než běžné manipulátory se sériovou kinematickou strukturou. Obecnou nevýhodou paralelních mechanismů bývá jejich relativně malá pracovní oblast oproti sériovým, složitější struktura a komplikované řešení přímé kinematické úlohy. Předkládaná práce přináší efektivní řešení přímé kinematické úlohy pomocí simulačního modelu s fuzzy inferenčním systémem typu Takagi-Sugeno. Navržený systém řízení využívá stavových a fuzzy regulátorů typu Takagi-Sugeno, které jsou odvozeny od stavových regulátorů s integrací na vstupu. Pro návrh a optimalizaci fuzzy regulátorů byla použita technika anfis (adaptive neuro-fuzzy inference system), která emuluje trénovací data pomocí trénování s použitím metody nejmenších čtverců v kombinaci s metodou zpětného šíření. Navržené fuzzy regulátory jsou použity pro řízení jednotlivých ramen manipulátoru. Vlastnosti navrženého systému řízení jsou dokumentovány testovacím experimentem.The Ph.D. thesis is focused on using the fuzzy logic for control of a parallel manipulator based on a Stewart platform. The proposed mechanism makes possible to simulate the physiological movements of the human body and observe degradation processes of the cord implants. Parallel manipulators such as a Stewart platform represent a completely parallel kinematic mechanism that has major differences from typical serial link robots. However, they have some drawbacks of relatively small workspace and difficult forward kinematic problems. Generally, forward kinematic of a parallel manipulators is very complicated and difficult to solve. This thesis presents a simple and efficient approach to design simulation model of forward kinematic based on Takagi-Sugeno type fuzzy inference system. The control system of the parallel manipulator id based on state-space and fuzzy logic controllers. The proposed fuzzy controller uses a Sugeno type fuzzy inference system (FIS) which is derived from discrete position state-space controller with an input integrator. The controller design method is based on anfis (adaptive neuro-fuzzy inference system) training routine. It utilizes a combination of the least-squares method and the backpropagation gradient descent method for training FIS membership function parameters to emulate a given training data set. The proposed fuzzy logic controllers are used for the control of a linear actuator. The capabilities of the designed control system are shown on verification experiment.

    Kinematics and Robot Design I, KaRD2018

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    This volume collects the papers published on the Special Issue “Kinematics and Robot Design I, KaRD2018” (https://www.mdpi.com/journal/robotics/special_issues/KARD), which is the first issue of the KaRD Special Issue series, hosted by the open access journal “MDPI Robotics”. The KaRD series aims at creating an open environment where researchers can present their works and discuss all the topics focused on the many aspects that involve kinematics in the design of robotic/automatic systems. Kinematics is so intimately related to the design of robotic/automatic systems that the admitted topics of the KaRD series practically cover all the subjects normally present in well-established international conferences on “mechanisms and robotics”. KaRD2018 received 22 papers and, after the peer-review process, accepted only 14 papers. The accepted papers cover some theoretical and many design/applicative aspects

    An Examination of the Use of Reading Fluency Indicators to Predict ACT Sub-Scores of First-Year College Students

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    Using Tinto’s student departure theory (Tinto, 1975, 1993, 2012) and the simple view of reading (Hoover & Gough, 1990), this study explores the relationship between reading fluency indicators and achievement on the ACT reading sub-test and the ACT composite score. The study utilizes reading samples obtained from first-year college students attending a small, private university in the southeastern United States. A non-random sample of students (n = 95) was recorded while reading a college-level, informational passage measured at the 1470 Lexile level. Results of using hierarchical linear regression revealed that word reading accuracy as measured by reading miscues predicted unique variance in both ACT reading sub-scores and in ACT composite scores. Reading miscues explained 19.2% of the variance in the ACT reading sub-score and 24.0% of the variance in ACT composite scores. Issues of college-student literacy, readiness, and persistence to degree completion are explored. Implications of the study support the need for pre-matriculation indicators of incoming student academic competencies for universities to provide equitable and adequate academic support for all students for persistence to degree completion

    Visual Servoing in Robotics

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    Visual servoing is a well-known approach to guide robots using visual information. Image processing, robotics, and control theory are combined in order to control the motion of a robot depending on the visual information extracted from the images captured by one or several cameras. With respect to vision issues, a number of issues are currently being addressed by ongoing research, such as the use of different types of image features (or different types of cameras such as RGBD cameras), image processing at high velocity, and convergence properties. As shown in this book, the use of new control schemes allows the system to behave more robustly, efficiently, or compliantly, with fewer delays. Related issues such as optimal and robust approaches, direct control, path tracking, or sensor fusion are also addressed. Additionally, we can currently find visual servoing systems being applied in a number of different domains. This book considers various aspects of visual servoing systems, such as the design of new strategies for their application to parallel robots, mobile manipulators, teleoperation, and the application of this type of control system in new areas

    Industrial Robotics

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    This book covers a wide range of topics relating to advanced industrial robotics, sensors and automation technologies. Although being highly technical and complex in nature, the papers presented in this book represent some of the latest cutting edge technologies and advancements in industrial robotics technology. This book covers topics such as networking, properties of manipulators, forward and inverse robot arm kinematics, motion path-planning, machine vision and many other practical topics too numerous to list here. The authors and editor of this book wish to inspire people, especially young ones, to get involved with robotic and mechatronic engineering technology and to develop new and exciting practical applications, perhaps using the ideas and concepts presented herein

    On the design of multi-platform parallel mechanisms

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    Parallel mechanisms have been examined in more and more detail over the past two decades. Parallel mechanisms are essentially the same design layout, a base, multiple legs/limbs, and a moving platform with a single end-effector to allow the mechanism to complete its desired function. Recently, several research groups have begun looking into multiple-platform parallel mechanisms and/or multiple end-effectors for parallel mechanisms. The reason for the research in this new form of parallel mechanism stems from multiple sources, such as applications that would require multiple handling points being accessed simultaneously, a more controlled gripper motion by having the jaws of the gripper being attached at different platforms, or to increasing the workload of the mechanism. The aim of the thesis is to modify the design process of parallel mechanisms so that it will support the development of a new parallel mechanism with multiple platforms capable of moving relative to each other in at least 1-DOF and to analyse the improvements made on the traditional single platform mechanism through a comparison of the power requirements for each mechanism. Throughout the thesis, a modified approach to the type synthesis of a parallel mechanism with multiple moving platforms is proposed and used to create several case study mechanisms. Additionally, this thesis presents a new series of methods for determining the workspace, inverse kinematic and dynamic models, and the integration of these systems into the design of a control system. All methods are vetted through case studies where they are judged based on the results gained from existing published data. Lastly, the concepts in this thesis are combined to produce a physical multi-platform parallel mechanism case study with the process being developed at each stage. Finally, a series of proposed topics of future research are listed along with the limitations and contributions of this work
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