384 research outputs found

    Parallel Manipulators

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    In recent years, parallel kinematics mechanisms have attracted a lot of attention from the academic and industrial communities due to potential applications not only as robot manipulators but also as machine tools. Generally, the criteria used to compare the performance of traditional serial robots and parallel robots are the workspace, the ratio between the payload and the robot mass, accuracy, and dynamic behaviour. In addition to the reduced coupling effect between joints, parallel robots bring the benefits of much higher payload-robot mass ratios, superior accuracy and greater stiffness; qualities which lead to better dynamic performance. The main drawback with parallel robots is the relatively small workspace. A great deal of research on parallel robots has been carried out worldwide, and a large number of parallel mechanism systems have been built for various applications, such as remote handling, machine tools, medical robots, simulators, micro-robots, and humanoid robots. This book opens a window to exceptional research and development work on parallel mechanisms contributed by authors from around the world. Through this window the reader can get a good view of current parallel robot research and applications

    Cooperative Control of the Dual Gantry-Tau Robot

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    Utilization of multiple parallel robots operating in the same work place and cooperating on the same job have opened up new challenges in coordination control strategies. Multiple robot control is a natural progression for Parallel Kinematic Machines (PKM) as it offers many of the desirable qualities especially in cooperative arrangements where multiple robots can be associated with an easily reconfigurable parallel machine. These special characteristics allow much faster and precise manipulations especially in manufacturing industries. With the possibility of cooperative control architecture, PKMs will be able to perform many of the tasks currently requiring dual serial robots such as complex assemblies, heavy load sharing and large machining jobs

    Kinematics and Robot Design II (KaRD2019) and III (KaRD2020)

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    This volume collects papers published in two Special Issues “Kinematics and Robot Design II, KaRD2019” (https://www.mdpi.com/journal/robotics/special_issues/KRD2019) and “Kinematics and Robot Design III, KaRD2020” (https://www.mdpi.com/journal/robotics/special_issues/KaRD2020), which are the second and third issues of the KaRD Special Issue series hosted by the open access journal robotics.The KaRD series is an open environment where researchers present their works and discuss all topics focused on the many aspects that involve kinematics in the design of robotic/automatic systems. It aims at being an established reference for researchers in the field as other serial international conferences/publications are. Even though the KaRD series publishes one Special Issue per year, all the received papers are peer-reviewed as soon as they are submitted and, if accepted, they are immediately published in MDPI Robotics. 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”.KaRD2019 together with KaRD2020 received 22 papers and, after the peer-review process, accepted only 17 papers. The accepted papers cover problems related to theoretical/computational kinematics, to biomedical engineering and to other design/applicative aspects

    On adaptive robot systems for manufacturing applications

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    System adaptability is very important to current manufacturing practices due to frequent changes in the customer needs. Two basic concepts that can be employed to achieve system adaptability are flexible systems and modular systems. Flexible systems are fixed integral systems with some adjustable components. Adjustable components have limited ranges of parameter changes that can be made, thus restricting the adaptability of systems. Modular systems are composed of a set of pre-existing modules. Usually, the parameters of modules in modular systems are fixed, and thus increased system adaptability is realized only by increasing the number of modules. Increasing the number of modules could result in higher costs, poor positioning accuracy, and low system stiffness in the context of manufacturing applications. In this thesis, a new idea was formulated: a combination of the flexible system and modular system concepts. Systems developed based on this new idea are called adaptive systems. This thesis is focused on adaptive robot systems. An adaptive robot system is such that adaptive components or adjustable parameters are introduced upon the modular architecture of a robot system. This implies that there are two levels to achieve system adaptability: the level where a set of modules is appropriately assembled and the level where adjustable components or parameters are specified. Four main contributions were developed in this thesis study. First, a General Architecture of Modular Robots (GAMR) was developed. The starting point was to define the architecture of adaptive robot systems to have as many configuration variations as possible. A novel application of the Axiomatic Design Theory (ADT) was applied to GAMR development. It was found that GAMR was the one with the most coverage, and with a judicious definition of adjustable parameters. Second, a system called Automatic Kinematic and Dynamic Analysis (AKDA) was developed. This system was a foundation for synthesis of adaptive robot configurations. In comparison with the existing approach, the proposed approach has achieved systemization, generality, flexibility, and completeness. Third, this thesis research has developed a finding that in modular system design, simultaneous consideration of both kinematic and dynamic behaviors is a necessary step, owing to a strong coupling between design variables and system behaviors. Based on this finding, a method for simultaneous consideration of type synthesis, number synthesis, and dimension synthesis was developed. Fourth, an adaptive modular Parallel Kinematic Machine (PKM) was developed to demonstrate the benefits of adaptive robot systems in parallel kinematic machines, which have found many applications in machine tool industries. In this architecture, actuators and limbs were modularized, while the platforms were adjustable in such a way that both the joint positions and orientations on the platforms can be changed

    Microfactory concept with bilevel modularity

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    There has been an increasing demand for miniaturization of products in the last decades. As a result of that, miniaturization and micro systems have become an important topic of research. As the technologies of micro manufacturing improve and are gradually started to be used, new devices have started to emerge in to the market. However, the miniaturization of the products is not paralleled to the sizes of the equipment used for their production. The conventional equipment for production of microparts is comparable in size and energy consumption to their counterparts in the macro world. The miniaturization of products and parts is slowly paving the way to the miniaturization of the production equipment and facilities, enabling efficient use of energy for production, improvement in material resource utilization and high speed and precision which in turn will lead to an increase in the amount of products produced more precisely. These led to the introduction of the microfactory concept which involves the miniaturization of the conventional production systems with all their features trying to facilitate the advantages that are given above. The aim of this thesis is to develop a module structure for production and assembly which can be cascaded with other modules in order to form a layout for the production of a specific product. The layout can also be changed in order to configure the microfactory for the production of another product. This feature brings flexibility to the system in the sense of product design and customization of products. Each module having its own control system, is able to perform its duty with the equipment placed into it. In order to form different layouts using the modules to build up a complete production chain, each module is equipped with necessary interface modules for the interaction and communication with the other process modules. In this work, the concept of process oriented modules with bilevel modularity is introduced for the development of microfactory modules. The first phase of the project is defined to be the realization of an assembly module and forms the content of this thesis. The assembly module contains parallel kinematics robots as manipulators which performs the assigned operations. One of the most important part here is to configure the structure of the module (control system/interface and communication units, etc.) which will in the future enable the easy integration of different process modules in order to form a whole microfactory which will have the ability to perform all phases of production necessary for the manufacturing of a product. The assembly module is a miniaturized version of the conventional factories (i.e. an assembly line) in such a way that the existing industrial standards are imitated within the modules of the microfactory. So that one who is familiar with the conventional systems can also be familiar with the construction of the realized miniature system and can easily setup the system according to the needs of the application. Thus, this is an important step towards the come in to use of the miniaturized production units in the industry. In order to achieve that kind of structure, necessary control hardware and software architecture are implemented which allows easy configuration of the system according to the processes. The modularity and reconfigurability in the software structure also have significant importance besides the modularity of the mechanical structure. The miniaturization process for the assembly cell includes the miniaturization of the parallel manipulators, transportation system in between the assembly nodes or in between different modules and the control system hardware. Visual sensor utilization for the visual feedback is enabled for the assembly process at the necessary nodes. The assembly module is developed and experiments are realized in order to test the performance of the module

    Robot Manipulators

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    Robot manipulators are developing more in the direction of industrial robots than of human workers. Recently, the applications of robot manipulators are spreading their focus, for example Da Vinci as a medical robot, ASIMO as a humanoid robot and so on. There are many research topics within the field of robot manipulators, e.g. motion planning, cooperation with a human, and fusion with external sensors like vision, haptic and force, etc. Moreover, these include both technical problems in the industry and theoretical problems in the academic fields. This book is a collection of papers presenting the latest research issues from around the world

    Proceedings of the NASA Conference on Space Telerobotics, volume 4

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    Papers presented at the NASA Conference on Space Telerobotics are compiled. The theme of the conference was man-machine collaboration in space. The conference provided a forum for researchers and engineers to exchange ideas on the research and development required for the application of telerobotic technology to the space systems planned for the 1990's and beyond. Volume 4 contains papers related to the following subject areas: manipulator control; telemanipulation; flight experiments (systems and simulators); sensor-based planning; robot kinematics, dynamics, and control; robot task planning and assembly; and research activities at the NASA Langley Research Center

    Technology for the Future: In-Space Technology Experiments Program, part 2

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    The purpose of the Office of Aeronautics and Space Technology (OAST) In-Space Technology Experiments Program In-STEP 1988 Workshop was to identify and prioritize technologies that are critical for future national space programs and require validation in the space environment, and review current NASA (In-Reach) and industry/ university (Out-Reach) experiments. A prioritized list of the critical technology needs was developed for the following eight disciplines: structures; environmental effects; power systems and thermal management; fluid management and propulsion systems; automation and robotics; sensors and information systems; in-space systems; and humans in space. This is part two of two parts and contains the critical technology presentations for the eight theme elements and a summary listing of critical space technology needs for each theme
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