Assembly Simplification Research Articles

Advanced data handling architecture for earth observation satellites

Abstract In this paper we describe how commercial open standards for embedded systems could affect the architecture of future satellite data handling systems. Traditionally, satellite data handling systems are based on the principles of a federated architecture, i. e. one function is implemented as one box. Each box has its own housing and power supply. In the paper we describe the transition path from the traditional federated architecture to a centralized but modular architecture based on adapted industrial standards. In the presented approach functional modules like on-board computer, Global Navigation Satellite System receiver, interface boards, etc. are combined in a rack communicating via a standard backplane using standardized communication links. The analysis performed during the Advanced Data Handling Architecture study showed that this approach contributes significantly to mass and power reduction (approx. 20 %) of a typical satellite data handling system. Another major point highlighted in the Advanced Data Handling Architecture study is the simplification of Assembly, Integration and Test activities. All this will help space industry to handle increasing system complexity while keeping costs at an acceptable level.

A CAD Assembly Simplification Approach with Ray Casting

A CAD Assembly Simplification Approach with Ray Casting

Freeform-objective Chernin multipass cell: application of a freeform surface on assembly simplification.

This paper aims at decreasing the assembly difficulty and reducing the cost of optical systems using multiple components. A strategy is proposed to substitute one freeform surface for multi-separated surfaces. A freeform-objective Chernin multipass cell is implemented as a typical instance for assembly simplification. The application of a freeform surface helps in decreasing the degree of objective assembly tolerances from 24 to 4, by representing the original four objectives with a linear combination of a 2D Gaussian radial basis function, which is analytical, global C∞ smooth, and locally influencing. The simulation result verifies the feasibility and performance of the designed freeform-objective Chernin multipass cell, whose base length is 0.2m, volume is less than 0.8 L, and adjustable optical length is 0.4-34m. Results prove that by using a proper approach to approximate the original surfaces as an integrated freeform, one can simultaneously reduce the assembly cost and the assembly difficulty.

Mobile 3D assembly process information construction and transfer to the assembly station of complex products

ABSTRACTIn the model-based definition design and manufacturing environment, 3D models have integrated the complete definition information of a product. Thus, they have been treated as the single data source for design and manufacturing stages in the product development lifecycle. Transferring the 3D models to the assembly station is crucial for facilitating the integration of the design and manufacturing processes of complex products and is full of challenges. This paper proposes a framework for mobile 3D assembly process information (API) construction and transfer to the assembly station of complex products with the purpose of providing direct and unambiguous assembly instruction to assembly operators, hence reducing their mental burden and improving the efficiency of assembly work. Within the framework, a dynamic assembly simplification method is investigated to support the downstream 3D API construction and transfer. After analysing the association relationship between assembly scene elements, an augmented reality (AR)-based method for 3D API construction and transfer is presented by merging the information of the assembly scene. The proposed approach has been tested on several test cases, and the results indicate that the improved dynamic assembly simplification method can search assembly features more efficiently compared to the divide-and-conquer algorithm and that the AR-based 3D API intuitively shows the assembly process.

Design Optimization of a Flexible Hinge Compliant Micro icro-Gripper ripper Mechanism with Parallel Movement Arms Using Pseudo-Rigid -Body Model

Abstract: Nano/Micro-electro-mechanical-system (NEMS/MEMS) consists of couplings of electrical and mechanical components within the micro-scale. Their nonlinear working state makes their analysis complex and complicated. Compliant mechanisms can (CMs) achieve a specified motion as a mechanism without relying on the use of joints and pins. They have broad application in precision mechanical devices and Nano/Micro-electro-mechanical-systems. Compliant mechanisms are suggested as alternates for simplification of assembly and for miniaturization. The design synthesis of compliant mechanisms yields optimized topologies that combine several stiff parts with highly elastic flexural hinges. In this paper, Finite Element Analysis (FEA) analysis and design of a compliant micro-gripper compliant mechanism with parallel movement arm are presented by employing its Pseudo Rigid Body Model (PRBM), which leads to the establishment of high performance mechanism. This micro-gripper is capable of delivering high precision and fidelity manipulation of micro objects. The mechanism adopts a flexure-based concept on its joints to address the inherent nonlinearities associated with the application of conventional rigid hinges.

Dynamic assembly simplification for virtual assembly process of complex product in cloud computing environment

Three-dimensional model–based virtual assembly process planning plays an important role in assembly design of complex product and is typically time- and resource-intensive. There are limited effective solution frameworks for delivering the three-dimensional model–based assembly process information to assembly field in order to directly guide the assembly tasks on site. A cloud service architecture for mobile three-dimensional model is proposed to address these challenges. Under this cloud computing architecture, this article introduces a dynamic assembly simplification approach, which regards the virtual assembly process of complex product as an incremental growth process of dynamic assembly. During the growth process, the current-assembled-state assembly model is simplified with appearance preserved by detecting and removing its invisible features, and the to-be-assembled components are simplified with assembly features preserved using conjugated subgraphs matching method based on MapReduce. The proposed approach has been tested on several cases, and the results show its feasibility and superiority.

Dynamic assembly simplification for virtual assembly process of complex product

Purpose – Virtual assembly process plays an important role in assembly design of complex product and is typically time- and resource-intensive. This paper aims to investigate a dynamic assembly simplification approach in order to demonstrate and interact with virtual assembly process of complex product in real time. Design/methodology/approach – The proposed approach regards the virtual assembly process of complex product as an incremental growth process of dynamic assembly. During the growth process, the current-assembled-state assembly model is simplified with appearance preserved by detecting and removing its invisible features, and the to-be-assembled components are simplified with assembly features preserved using conjugated subgraphs matching method based on an improved subgraph isomorphism algorithm. Findings – The dynamic assembly simplification approach is applied successfully to reduce the complexity of computer aided design models during the virtual assembly process and it is proved by several cases. Originality/value – A new assembly features definition is proposed based on the notion of “conjugation” to assist the assembly features recognition, which is a main step of the dynamic assembly simplification and has been translated into conjugated subgraphs matching problem. And an improved subgraph isomorphism algorithm is presented to address this problem.

플랜지 형성 액압성형시 공정변수에 따른 성형 특성

Hydroforming is the technology that utilizes hydraulic pressure to form tube or sheet materials into desired shapes inside die cavities. Tube hydroforming provides a number of advantages over the conventional stamping process, including fewer secondary operations, weight reduction, assembly simplification, adaptability to forming of complex structural components and improved structural strength. In many case, hydroformed parts have to be structurally joined at some point. Therefore it is useful if the hydroformed automotive parts can be given a localized attachment flange. In this study for the numerical process design FE analysis was performed with DYNAFORM 5.5. Die parting angle and circumferential expansion ratio was optimized. With optimized condition, bulge and hydroforming experiments to form flange were performed. Forming characteristic at various pressure conditions was analyzed and optimized internal pressure condition was evaluated. The results show that flanged parts can be successfully produced by tube hydroforming process.

Compliant design for flapping mechanism: A minimum torque approach

Compliant mechanisms are suggested as alternates for simplification of assembly and for miniaturization. It is shown here that a significant reduction in running torque could be achieved through proper design. The dynamics of a four-bar crank-rocker mechanism, suitable as a flapping mechanism and consisting of two flexural hinges is analyzed. The peak driving torque is minimized by modifying the stiffness of the flexural hinges and the unstrained positions of the flexural hinges. A reduction of the order of 2.85 in the peak driving torque is achieved in a specific mechanism considered.

Effect of Heat Treatment Conditions on Tube Hydroformability

Tube hydroforming provides a number of advantages over conventional stamping process, including fewer secondary operations, weight reduction, assembly simplification, adaptability to forming of complex structural components and improved structural strength and stiffness. It can produce wide range of products such as sub-frame, engine cradle, and exhaust manifold. In this study, the effect of heat treatment conditions, such as post seam annealing(PSA) and bright annealing(BA), on the ovality and hydro-formability of steel tubes has been investigated. Hydroformability has been estimated as the bulging height obtained depending on the various process parameters such as an internal pressure, axial feeding, and heat treatment conditions. The ovality and forming height were found to strongly depend on material properties after heat treatments.

Soft Magnetic Composite Materials Applied to Electric Motors

SummaryThe advent of soft magnetic composites (SMC) opens the arena for innovative electrical machine designs with three dimensional flux paths for mass production. The key to commercial success lies in interactive multi-disciplinary co-operation with parallel development activities.The SMC materials are based on iron powder particles with surface insulation for low eddy current loss. Insulated particles, such as those used for dust cores have existed for many years, however these low density products with permeability values of 150 to 200 and low saturation induction are better suited to high frequency applications. The thin inorganic insulation of the SMC materials allows heat treatment at 500°C, which results in a partial stress relief and permeabilities of 500 and above. High flux density requires high component density, which is achieved with high compressibility powders. The compressibility of the powder is dependent on the surface coating, which must be minimized. The SMC materials are suitable for large scale mass production of complex components with good tolerances, smooth surfaces, no secondary operations and no material waste.Electrical machines with two dimensional flux paths benefit from the use of laminated electrical steel as the anisotropic properties are put to advantage. Machines such as claw pole motors, transverse flux machines etc. have not achieved widespread industrial use, as these require a material with isotropic properties suitable for mass production. However SMC material data alone is insufficient as the sole aspect for design focus. A new design should incorporate all aspects of the new motor including windings, permanent magnets, reduction in the number of parts and simplification of assembly. It is first when all the advantages of concurrent engineering are applied that full commercial success can be achieved.