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research-article  
Edoh Goka, Lazhar Homri, Pierre Beaurepaire and Jean-Yves Dantan
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4042018
Tolerance analysis aims towards the verification impact of the individual tolerances on the assembly and functional requirements of a mechanism. The manufactured products have several types of contact and are inherent in imperfections, which often causes the failure of the assembly and its functioning. Tolerances are therefore allocated to each part of the mechanism in purpose to obtain an optimal quality of the final product. Three main issues are generally defined to realize the tolerance analysis of a mechanical assembly: the geometrical deviations modeling, the geometrical behavior modeling and the tolerance analysis techniques. In this paper, a method is proposed to realize the tolerance analysis of an over-constrained mechanical assembly with form defects by considering the contacts nature (fixed, sliding, and floating contacts) in its geometrical behavior modeling. Different optimization methods are used to study the different contact types. The overall statistical tolerance analysis of the over-constrained mechanical assembly is carried out by determining the assembly and the functionality probabilities based on optimization techniques combined with a Monte Carlo Simulation (MCS). An application to an over-constrained mechanical assembly is given at the end.
research-article  
Mehdi Dehghani, Hamed Kharrati, Mirhadi Seyedarabi and Mahdi Baradarannia
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041969
The accumulated error as well as the noise sensitivity, are the two common problems of ordinary inertial sensors. An accurate gyroscope is too expensive which is not normally applicable in low-cost missions of mobile robots. Since the accelerometers are rather cheaper than similar types of gyroscopes, using redundant accelerometers could be considered as an alternative. This mechanism is called Gyroscope-free navigation. The article deals with Autonomous mobile robot navigation based on Gyroscope-free method. In this research, the navigation errors of the Gyroscope-free method in long-time missions are demonstrated. To compensate the position error, the aid information of low-cost stereo cameras and a topological map of the workspace are employed in the navigation system. After precise sensor calibration, an amendment algorithm is presented to fuse the measurement of GFIMU (Gyroscope-free inertial measurement unit) and stereo camera observations. The advantages and comparisons of vision aid navigation and Gyroscope-free navigation of mobile robots will be also discussed. The experimental results show increasing the accuracy in vision-aid navigation of mobile robot.
TOPICS: Navigation, Mobile robots, Errors, Sensors, Accelerometers, Noise (Sound), Algorithms, Calibration, Measurement units and standards
research-article  
Sif Edine Sadaoui, Charyar Mehdi-Souzani and C Lartigue
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041970
Computer-Aided Inspection Planning (CAIP) has gained significant research attention in the last years. So far, most CAIP systems have focused on the use of a touch probe mounted on a Coordinate Measuring Machine (CMM). This article investigates multi-sensor measurement aiming to perform automatic and efficient inspection plans. High level inspection planning, which deals with sequencing of measuring operations, is the main concern of inspection planning. This paper presents an automatic approach to generate inspection sequences by combining laser sensor and touch probe, and by giving preference to the measurement using the laser sensor if quality requirements are satisfied. The proposed approach consists of three steps. In the first step, recognition of inspection data from the CAD part model is carried out based on the concept of inspection feature, and the extracted information is stored in a database. In the second step, a list of privileged scanner orientations is proposed by analyzing the accessibility of both sensors. In the third step, a sequence of operations is generated iteratively. For a given scanner orientation, the ability of the laser sensor is assessed according to an original process based on fuzzy logic model. If the laser sensor does not meet the ability requirements, probe ability is assessed. The proposed approach is implemented and tested on a part defined by its CAD model and specifications
TOPICS: Sensors, Inspection, Computer-aided engineering, Lasers, Probes, Coordinate measuring machines, Computer-aided design, Databases, Preferences, Fuzzy logic
research-article  
Yuen-Shan Leung, Tsz Ho Kwok, Xiangjia Li, Yang Yang, Charlie C.L. Wang and Yong Chen
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041913
The revolution of additive manufacturing (AM) has led to many opportunities in fabricating complex and novel products. The increase of the printable materials and the emergence of the various fabricating processes continuously expand the capability of manufacturing. Our products are no longer limited to be single material, single scale or single function. In fact, a paradigm shift is taking place in the industries from geometry-centered usage to support functional demands, and hence it is expected to resolve wide range of complex and difficult problems. Although AM provides us higher design degree of freedom beyond the geometry to fabricate new objects with tailored properties and functions, there are only very few approaches for computational design in this new domain enabled by AM. The objectives of this study are to provide an overview on the current computer-aided design methodologies that are applied to multi-material, multi-scale, multi-form and multi-functional AM technologies. We summarize the difficulties encountered in the design approaches and emphasize the need for the future development. The study also introduces the related manufacturing processes, lists their present applications, and discusses their potential future trends.
TOPICS: Design, Computation, Additive manufacturing, Geometry, Manufacturing, Degrees of freedom, Computer-aided design
research-article  
Hau Dang-Trung, Dane Jong Yang and Yu-Cheng Liu
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041829
In this paper, the authors present a finite element method based on Chebyshev polynomials (CFE) for the analysis of Reissner-Mindlin plates and shells. Chebyshev polynomials are a sequence of orthogonal polynomials that are defined recursively. The values of the polynomials belong to the interval and vanish at the Gauss points. Therefore, high-order shape functions, which satisfy the interpolation condition at the points, can be performed with Chebyshev polynomials. Full gauss quadrature rule was used for stiffness matrix, mass matrix and load vector calculations. Static and free vibration analyses of thick and thin plates and shells with several different shapes subjected to different boundary conditions were carried out. Both regular and irregular meshes were considered. The obtained results showed that by increasing the order of the shape functions, CFE automatically overcomes shear locking without the formation of spurious zero energy modes. Moreover, the results of CFE are in close agreement with the exact solution even for coarse and irregular meshes.
TOPICS: Shear (Mechanics), Finite element methods, Polynomials, Shapes, Shells, Plates (structures), Boundary-value problems, Free vibrations, Interpolation, Stiffness, Stress
research-article  
Anthony P. Garland and Georges Fadel
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041744
The goal of this research is to optimize an object's macroscopic topology and localized gradient material properties subject to multiple loading conditions simultaneously. The gradient material of each macroscopic cell is modeled as an orthotropic material where the elastic moduli in two local orthogonal directions we call x and y can change. Furthermore, the direction of the local coordinate system can be rotated to align with the loading conditions on each cell. This orthotropic material is similar to a fiber-reinforced material where the number of fibers in the local x and y-directions can change for each cell, and the directions can as well be rotated. Repeating cellular unit cells which form a mesostructure can also achieve these customized orthotropic material properties. Homogenization theory allows calculating the macroscopic averaged bulk properties of these cellular materials. By combining topology optimization with gradient material optimization and fiber orientation optimization, the proposed algorithm significantly decreases the objective, which is to minimize the strain energy of the object subject to multiple loading conditions. Additive manufacturing techniques enable the fabrication of these designs by selectively placing reinforcing fibers or by printing different mesostructures in each region of the design. This work shows a comparison of simple topology optimization, topology optimization with isotropic gradient materials, and topology optimization with orthotropic gradient materials. Finally, a trade-off experiment shows how different optimization parameters, which affect the range of gradient materials used in the design, have an impact on the final objective value of the design.
TOPICS: Design, Topology, Optimization, Fibers, Materials properties, Algorithms, Manufacturing, Elastic moduli, Printing, Additive manufacturing, Tradeoffs
research-article  
Xiao-Jin Wan, Licheng Liu, Zengbing Xu and Zhigang Xu
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041776
In this work, a Soft Competitive Learning Fuzzy Adaptive Resonance Theory (SFART) diagnosis model based on multi-feature domain selection for the single symptom domain and the single-target model is proposed. In order to solve the problem that the performance of traditional Fuzzy ART(FART) is affected by the order of sample input, the similarity criterion of YU norm is introduced into the Fuzzy ART network. In the meanwhile, the lateral inhibition theory is introduced to solve the wasteful problem of fuzzy ART mode node. By combining YU norm and lateral inhibition theory with Fuzzy ART network, a soft competitive learning ART neural network diagnosis model that allows multiple mode nodes to learn simultaneously is designed. The feature parameters are extracted from the perspectives of time domain, frequency domain, time series model, wavelet analysis and wavelet packet energy spectrum analysis, respectively. To further improve the diagnostic accuracy, the selective weighted majority voting method is integrated into the diagnosis model. Finally, the selected feature parameters are inputted to the integrated model to complete the fault classification and diagnosis. Finally, the proposed method is verified with a gearbox fault diagnosis test.
TOPICS: Mechanical drives, Fault diagnosis, Wavelets, Resonance, Time series, Spectroscopy, Emission spectroscopy, Artificial neural networks
research-article  
Cong Hong Phong Nguyen and Young Choi
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041777
The lightweight representation of three-dimensional computer-aided design (3D CAD) models has drawn much attention from researchers as its usefulness in collaborative product development is vast. Existing approaches are mostly based on feature depression or mesh-based simplification. In this article, a new approach for 3D CAD lightweight representation based on combining triangular mesh representation and boundary representation (B-rep) is proposed. The corresponding data structure as well as the conversion method from original data given in B-rep was developed. Considered as an essential application in collaborative product development, a case study on the visualization process of large-scale assembly models represented in the proposed lightweight representation was also conducted. The validation of the approach was performed via experiments with 3D CAD models in SAT format and by benchmarking with the conventional all-faceted approach with the same level of mesh resolution.
TOPICS: Product development, Three-dimensional computer-aided design, Manufacturing, Resolution (Optics), Visualization
research-article  
Ashok V. Kumar
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041705
Optimal layouts for structural design have been generated using topology optimization approach with a wide variety of objectives and constraints. Minimization of compliance is the most common objective but the resultant structures often have stress concentrations. Two new objective functions, constructed using an upper bound of von Mises stress, are presented here for computing design concepts that avoid stress concentration. The first objective function can be used to minimize mass while ensuring that the design is conservative and avoids stress concentrations. The second objective can be used to trade off between maximizing stiffness versus minimizing the maximum stress to avoid stress concentration. The use of the upper bound of von Mises stress is shown to avoid singularity problems associated with stress based topology optimization. A penalty approach is used for eliminating stress concentration and stress limit violations which ensures conservative designs while avoiding the need for special algorithms for handling stress localization. In this work, shape and topology are represented using a density function with the density interpolated piece-wise over the elements to obtain a continuous density field. A few widely used examples are utilized to study these objective functions.
TOPICS: Stress, Conceptual design, Topology, Stress concentration, Density, Design, Optimization, Shapes, Stiffness, Structural design, Algorithms, Tradeoffs
research-article  
Samuel Lorin, Björn S. Lindau, Lars Lindkvist and Rikard Söderberg
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041706
During product development one important aspect is the geometric robustness of the design. This is due to the fact that all manufacturing processes lead to products with variation. Failing to properly account for the variability of the process in the design phase may lead to expensive redesign. One important tool during the design phase in many industries is variation simulation which makes it possible to predict and optimize the geometric quality of the design. However, despite the increase in computer power; calculation time is still an obstacle for the wider use of variation simulation. In this article we are proposing a new method for efficient compliant variation simulation of spot welded sheet metal assemblies. The method is exact and it is shown that the method leads to time savings in simulation of approximately 40%-50% compared to state-of-the-art in variation simulation.
TOPICS: Simulation, Design, Computers, Product development, Robustness, Manufacturing, Sheet metal
research-article  
Marco Mangiarotti, Francesco Ferrise, Serena Graziosi, Francesco Tamburrino and Monica Bordegoni
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041704
The paper describes the design of a wearable and wireless system that allows the real-time identification of some gestures performed by basketball players. This system is specifically designed as a support for coaches to track the activity of two, or more players simultaneously. Each wearable device is composed of two separate units, positioned on the wrists of the user, connected to a PC via Bluetooth. Each unit comprises a triaxial accelerometer and gyroscope, a micro-controller, installed on a TinyDuino platform, and a battery. The concept of activity recognition chain is investigated and used as a reference for the gesture recognition process. A sliding window allows the system to extract relevant features from the incoming data streams: mean values, standard deviations, maximum values, minimum values, energy and correlations between homologous axes are calculated to identify and differentiate the performed actions. Machine learning algorithms are implemented to handle the recognition phase
TOPICS: Design, Buses, Railroad passenger cars, Batteries, Machine learning, Control equipment, Accelerometers, Algorithms, Chain
research-article  
Qi Guo, Chengqi Xue, Mingjiu Yu and Zhangfan Shen
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041418
User requirements play an important role in product design activities, and the accurate and full acquisition of user requirements is directly related to customer satisfaction with product design. Implicit requirements are potential, fuzzy and subjective. In this paper, a new implicit user requirements process method based on the cloud service platform is proposed to solve the difficulty of implicit requirements acquisition. The method initially collects user requirements data by the metaphor extraction technique on the cloud service platform. Then, the requirements data are clustered and mapped with product attributes. The mapping result is then visualized to intuitively guide product design and optimization. This method is a user-centered innovation paradigm implemented on the cloud service platform, which can realize collaborative design and resource sharing. Finally, an application case is performed to illustrate the method, and the result indicates that the method is effective and can be used in product design.
TOPICS: Product design, Innovation, Design, Optimization

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