2,774 research outputs found

    Automatic generation of robot and manual assembly plans using octrees

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    This paper aims to investigate automatic assembly planning for robot and manual assembly. The octree decomposition technique is applied to approximate CAD models with an octree representation which are then used to generate robot and manual assembly plans. An assembly planning system able to generate assembly plans was developed to build these prototype models. Octree decomposition is an effective assembly planning tool. Assembly plans can automatically be generated for robot and manual assembly using octree models. Research limitations/implications - One disadvantage of the octree decomposition technique is that it approximates a part model with cubes instead of using the actual model. This limits its use and applications when complex assemblies must be planned, but in the context of prototyping can allow a rough component to be formed which can later be finished by hand. Assembly plans can be generated using octree decomposition, however, new algorithms must be developed to overcome its limitations

    Electroadhesion Technologies For Robotics:A Comprehensive Review

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    Phase Change Materials for Controllable Stiffness of Robotic Joints

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    Snake-like manipulators are well suited for operation in restricted and confined environments where the manipulator body can bend around obstacles to place an end effector at a difficult to access location. They require high stiffness when self-supporting weight against gravity and undertake precision manipulation task, but also require soft properties when operating in complex and delicate environments. A controllable stiffness manipulator has the potential to meet the application demands as it can switch between rigid and soft state. This thesis experimentally investigates the properties of four materials, (low melting point solder, hot-melt adhesive, low melting point alloy and granular material) as candidates for mechanically altering the stiffness of the joints/modules in snake-like manipulators. These materials were evaluated for bonding strength, repeatability, and activation time. Modules for a snake-like manipulator were fabricated using 3D printing and silicone casting techniques including, for the first time, variable stiffness joints that use hot-melt adhesive and low melting point alloy. These modules were evaluated for stiffness properties and low melting point solder based module was found to achieve a stiffness change 150X greater than the state of the art granular material approach. In addition, the proposed modules were able to support 25X of their own weight

    Workshop on "Robotic assembly of 3D MEMS".

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    Proceedings of a workshop proposed in IEEE IROS'2007.The increase of MEMS' functionalities often requires the integration of various technologies used for mechanical, optical and electronic subsystems in order to achieve a unique system. These different technologies have usually process incompatibilities and the whole microsystem can not be obtained monolithically and then requires microassembly steps. Microassembly of MEMS based on micrometric components is one of the most promising approaches to achieve high-performance MEMS. Moreover, microassembly also permits to develop suitable MEMS packaging as well as 3D components although microfabrication technologies are usually able to create 2D and "2.5D" components. The study of microassembly methods is consequently a high stake for MEMS technologies growth. Two approaches are currently developped for microassembly: self-assembly and robotic microassembly. In the first one, the assembly is highly parallel but the efficiency and the flexibility still stay low. The robotic approach has the potential to reach precise and reliable assembly with high flexibility. The proposed workshop focuses on this second approach and will take a bearing of the corresponding microrobotic issues. Beyond the microfabrication technologies, performing MEMS microassembly requires, micromanipulation strategies, microworld dynamics and attachment technologies. The design and the fabrication of the microrobot end-effectors as well as the assembled micro-parts require the use of microfabrication technologies. Moreover new micromanipulation strategies are necessary to handle and position micro-parts with sufficiently high accuracy during assembly. The dynamic behaviour of micrometric objects has also to be studied and controlled. Finally, after positioning the micro-part, attachment technologies are necessary

    Microrobots for wafer scale microfactory: design fabrication integration and control.

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    Future assembly technologies will involve higher automation levels, in order to satisfy increased micro scale or nano scale precision requirements. Traditionally, assembly using a top-down robotic approach has been well-studied and applied to micro-electronics and MEMS industries, but less so in nanotechnology. With the bloom of nanotechnology ever since the 1990s, newly designed products with new materials, coatings and nanoparticles are gradually entering everyone’s life, while the industry has grown into a billion-dollar volume worldwide. Traditionally, nanotechnology products are assembled using bottom-up methods, such as self-assembly, rather than with top-down robotic assembly. This is due to considerations of volume handling of large quantities of components, and the high cost associated to top-down manipulation with the required precision. However, the bottom-up manufacturing methods have certain limitations, such as components need to have pre-define shapes and surface coatings, and the number of assembly components is limited to very few. For example, in the case of self-assembly of nano-cubes with origami design, post-assembly manipulation of cubes in large quantities and cost-efficiency is still challenging. In this thesis, we envision a new paradigm for nano scale assembly, realized with the help of a wafer-scale microfactory containing large numbers of MEMS microrobots. These robots will work together to enhance the throughput of the factory, while their cost will be reduced when compared to conventional nano positioners. To fulfill the microfactory vision, numerous challenges related to design, power, control and nanoscale task completion by these microrobots must be overcome. In this work, we study three types of microrobots for the microfactory: a world’s first laser-driven micrometer-size locomotor called ChevBot,a stationary millimeter-size robotic arm, called Solid Articulated Four Axes Microrobot (sAFAM), and a light-powered centimeter-size crawler microrobot called SolarPede. The ChevBot can perform autonomous navigation and positioning on a dry surface with the guidance of a laser beam. The sAFAM has been designed to perform nano positioning in four degrees of freedom, and nanoscale tasks such as indentation, and manipulation. And the SolarPede serves as a mobile workspace or transporter in the microfactory environment

    A Study on Phase-Changing Materials for Controllable Stiffness in Robotic Joints

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    This paper studies the viability of using a class of phase-changing materials for the design of controlled variable stiffness robotic joints which enable the design of robots that can operate in confined spaces. In such environments, robots need to be able to navigate in proximity or while in contact with their environment to reach one or more manipulated target. Joints with controllable stiffness can substantially enhance functionality of this class of robots where relatively higher joint stiffness is required to support the robot weight against gravity and low stiffness is desired when operating in complex or delicate environments. The research work presented in this paper focuses on examining thermorheological fluids (TRF) to design and manufacture thermally controlled variable stiffness joints. Two phase-changing materials are considered in the study: low-melting-point solder and hot-melt adhesive. Both materials are embedded in a custom designed joint fabricated using 3D printing and silicone casting. Joint stiffness was investigated with both materials and reported here. The results shows that the proposed variable stiffness joints with TRF achieve wide ranges of load-deflection ratio varying between 0.05 N/mm (when thermally activated) to about 10 N/mm (in bonding state). On average, the joint can withstand 20 times its total weight when in the bonding state. Design challenges and durability of TRF-based joints are discussed

    High-Dimensional Design Evaluations For Self-Aligning Geometries

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    Physical connectors with self-aligning geometry aid in the docking process for many robotic and automatic control systems such as robotic self-reconfiguration and air-to-air refueling. This self-aligning geometry provides a wider range of acceptable error tolerance in relative pose between the two rigid objects, increasing successful docking chances. In a broader context, mechanical alignment properties are also useful for other cases such as foot placement and stability, grasping or manipulation. Previously, computational limitations and costly algorithms prevented high-dimensional analysis. The algorithms presented in this dissertation will show a reduced computational time and improved resolution for this kind of problem. This dissertation reviews multiple methods for evaluating modular robot connector geometries as a case study in determining alignment properties. Several metrics are introduced in terms of the robustness of the alignment to errors across the full dimensional range of possible offsets. Algorithms for quantifying error robustness will be introduced and compared in terms of accuracy, reliability, and computational cost. Connector robustness is then compared across multiple design parameters to find trends in alignment behavior. Methods developed and compared include direct simulation and contact space analysis algorithms (geometric by a \u27pre-partitioning\u27 method, and discrete by flooding). Experimental verification for certain subsets is also performed to confirm the results. By evaluating connectors using these algorithms we obtain concrete metric values. We then quantitatively compare their alignment capabilities in either SE(2) or SE(3) under a pseudo-static assumption

    Microsystems technology: objectives

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    This contribution focuses on the objectives of microsystems technology (MST). The reason for this is two fold. First of all, it should explain what MST actually is. This question is often posed and a simple answer is lacking, as a consequence of the diversity of subjects that are perceived as MST. The second reason is that a map of the somewhat chaotic field of MST is needed to identify sub-territories, for which standardization in terms of system modules an interconnections is feasible. To define the objectives a pragmatic approach has been followed. From the literature a selection of topics has been chosen and collected that are perceived as belonging to the field of MST by a large community of workers in the field (more than 250 references). In this way an overview has been created with `applications¿ and `generic issues¿ as the main characteristics
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