Shengfeng Qin

A conceptual design tool: a sketch and fuzzy logic based system

Abstract A real-time sketch and fuzzy logic based prototype system for conceptual design has been developed. This system comprises four phases. In the first one, the system accepts the input of online free-hand sketches, and segments them into meaningful parts by using fuzzy knowledge to detect corners and inflection points on the sketched curves. The fuzzy knowledge is applied to capture users drawing intention in terms of sketching position, direction, speed and acceleration. During the second phase, each segmented subpart (curve) can be classified and identified as one of the following two-dimensional primitives: straight lines, circles, circular arcs, ellipses, elliptical arcs or B-spline curves. Then, two-dimensional topology information (connectivity, unitary constraints and pairwise constraints) is extracted dynamically from the identified two-dimensional primitives. From the extracted information, more accurate two-dimensional geometry can be built up by a two-dimensional geometric constraint solver. The two-dimensional topology and geometry information is then employed to further interpretation of a three-dimensional geometry. The system can not only accept sketched input but also users’ interactive input of two- and three-dimensional primitives. This makes it friendly and easier to use, in comparison with ‘sketched input only’ or ‘interactive input only’ systems. Finally, examples are given to illustrate the system.

Instant 3D design concept generation and visualization by real-time hand gesture recognition

3D conceptual design is a creative process. While the designers are in the inspirational mode, they want to quickly express the design ideas in 3D and visualize it in real time without obstacle. In an exploration of a new, natural and more user friendly interface to assist rapid 3D conceptual generation and visualization, a prototype system of hand gesture and motion capture based user interface has been proposed and implemented. In this paper, we present the framework and components of this real time 3D conceptual generation and visualization system. Hand gestures were designed with the consideration of ease to use and the suitability for real time continuous recognition. Rule-based intelligent menu/icons were designed which changes the prompts according to the design process and expected operations. Real time hand gesture recognition was realized by skeleton model based template matching, and the use of hidden Markov models (HMMs). The recognized hand gestures become command script in OpenSCAD environment, and the 3D design concept was instantly generated and displayed on the screen. A case study was conducted for the initial evaluation of the system.

Exploring Barriers and Opportunities in Adopting Crowdsourcing Based New Product Development in Manufacturing SMEs

Crowdsourcing is an innovative business practice of obtaining needed services, ideas, or content or even funds by soliciting contributions from a large group of people (the ‘Crowd’). The potential benefits of utilizing crowdsourcing in product design are well-documented, but little research exists on what are the barriers and opportunities in adopting crowdsourcing in new product development (NPD) of manufacturing SMEs. In order to answer the above questions, a Proof of Market study is carried out on crowdsourcing-based product design under an Innovate UK funded Smart project, which aims at identifying the needs, challenges and future development opportunities associated with adopting crowdsourcing strategies for NPD. The research findings from this study are reported here and can be used to guide future development of crowdsourcing-based collaborative design methods and tools and provide some practical references for industry to adopt this new and emerging collaborative design method in their business.

Collaborative simulation method with spatiotemporal synchronization process control

When designing a complex mechatronics system, such as high speed trains, it is relatively difficult to effectively simulate the entire system’s dynamic behaviors because it involves multi-disciplinary subsystems. Currently, a most practical approach for multi-disciplinary simulation is interface based coupling simulation method, but it faces a twofold challenge: spatial and time unsynchronizations among multi-directional coupling simulation of subsystems. A new collaborative simulation method with spatiotemporal synchronization process control is proposed for coupling simulating a given complex mechatronics system across multiple subsystems on different platforms. The method consists of 1) a coupler-based coupling mechanisms to define the interfacing and interaction mechanisms among subsystems, and 2) a simulation process control algorithm to realize the coupling simulation in a spatiotemporal synchronized manner. The test results from a case study show that the proposed method 1) can certainly be used to simulate the sub-systems interactions under different simulation conditions in an engineering system, and 2) effectively supports multi-directional coupling simulation among multi-disciplinary subsystems. This method has been successfully applied in China high speed train design and development processes, demonstrating that it can be applied in a wide range of engineering systems design and simulation with improved efficiency and effectiveness.

A new design and grinding algorithm for ball-end milling cutter with tooth offset center

Ball-end milling cutter with tooth offset center is widely used in machining industry, because it has higher machining efficiency and better stability compared with the ball-end milling cutter without tooth offset center. In addition, the tooth offset center has lower wear rate of the tool tip so the life of the milling cutter is improved. However, up to present, there is no mature and effective theory for the design and manufacture of this kind of milling cutters. This article presents a new mathematical model for S-shaped edge curve of the ball end taking the tooth offset center into account, which can construct accurate S-shaped edge curve for the ball-end cutting tools with tooth offset center as well as without tooth offset center. This model overcomes the complex computation and bad adaptability of the traditional modeling method. At the same time, a five-axis grinding algorithm for rake face of the ball end is also presented in this article. Finally, based on the application programming interface of CATIA™, a three-dimensional computer-aided design and computer-aided manufacturing system is developed. The accuracy and effectiveness of the grinding algorithm are verified by simulation in VERICUT™ and machining experiment in tool grinding machine.

Feature-Based Human Model for Digital Apparel Design

Three-dimensional (3D) body scanning technology opens opportunities for virtual try-on and automatic made-to-measure apparel design. This paper proposes a new feature-based parametric method for modeling human body shape from scanned point clouds of a 3D body scanner [TC]2. The human body model consists of two layers: the skeleton and the cross sections of each body part. First, a simple skeleton model from the body scanner [TC]2 system has been improved by adding and adjusting the position of joints in order to better address some fit issues related to body shape changes such as spinal bending. Second, an automatic approach to extracting semantic features for cross sections has been developed based on the body hierarchy. For each cross section, it is described by a set of key points which can be fit with a closed cardinal spline. According to the point distribution in point clouds, an extraction method of key points on cross sections has been studied and developed. Third, this paper presents an interpolation approach to fitting the key points on a cross section to a cardinal spline, in which different tension parameters are tested and optimized to represent simple deformations of body shape. Finally, a connection approach of body parts is proposed by sharing a boundary curve. The proposed method has been tested with the developed virtual human model (VHM) system which is robust and easier to use. The model can also be imported in a CAD environment for other applications.

A holistic product design and analysis model and its application in railway vehicle systems design

For complex mechanical systems, to overcome design inconsistencies, it is becoming more and more necessary that product design system is effectively integrated with various analysis models and tools from multiple engineering domains at different design stages. In this article, a Holistic Product Design and Analysis Model, which is well supported by Top–Down design method, is conceptualized to define design and analysis integration at different levels, which will help enhance engineering design and analysis interoperability and integrate the design methods and analysis tools across multiple engineering domains. It is based on four design levels: system, subsystem, machine and component designs; at each level, design and analysis models are integrated under a Generalized Multirepresentation Architecture supporting design, analysis and optimization appropriately. For cross-level integration from top to bottom, the design models are transferred and mapped with more structural and geometric details, while analysis models obtain more detailed design constraints from the top levels. This new architecture has been developed and demonstrated with an application in a railway vehicle system design, although its optimization components have not been fully implemented. This model can be used for general mechanical product system design.

Cultural-based visual expression: emotional analysis of human face via Peking Opera Painted Faces (POPF)

Peking Opera as a branch of Chinese traditional cultures and arts has a very distinct colourful facial make-up for all actors in the stage performance. Such make-up is stylised in nonverbal symbolic semantics which all combined together to form the painted faces to describe and symbolise the background, the characteristic and the emotional status of specific roles. A study of Peking Opera Painted Faces (POPF) was taken as an example to see how information and meanings can be effectively expressed through the change of facial expressions based on the facial motion within natural and emotional aspects. The study found that POPF provides exaggerated features of facial motion through images, and the symbolic semantics of POPF provides a high-level expression of human facial information. The study has presented and proved a creative structure of information analysis and expression based on POPF to improve the understanding of human facial motion and emotion.

A new extracting algorithm of k nearest neighbors searching for point clouds

We propose an extracting algorithm for k nearest neighbors searching.Vector inner product instead of distance calculation for distance comparison.Extracting algorithm can integrate with any other algorithm as plug-in.Two prominent algorithms and seven models are employed to experiment.Open source of proposed algorithm using dynamic memory allocation. k Nearest neighbors (kNN) searching algorithm is widely used for finding k nearest neighbors for each point in a point cloud model for noise removal and surface curvature computation. When the number of points and their density in a point cloud model increase significantly, the efficiency of a kNN searching algorithm becomes critical to various applications, thus, a better kNN approach is needed. In order to improve the efficiency of a kNN searching algorithm, in this paper, a new strategy and the corresponding algorithm are developed for reducing the amount of target points in a given data set by extracting nearest neighbors before the search begins. The nearest neighbors of a reverse nearest neighborhood are proposed to use in extracting nearest points of a query point, avoiding repetitive Euclidean distance calculation in an extracting process for saving time and memories. For any point in the model, its initial nearest neighbors can be extracted from its reverse neighborhood using an inner product of two related vectors other than direct Euclidean distance calculations and comparisons. The initial neighbors can be its full or partial set of the all nearest neighbors. If it is a partial set, the rest can be obtained by using other fast searching algorithms, which can be integrated with the proposed approach. Experimental results show that integrating extracting algorithm proposed in this paper with other excellent algorithms provides a better performance by comparing to their performances alone.

Rapid 3D conceptual design based on hand gesture

The interaction method of current CAD systems has become one of the impediments of rapid 3D conceptual design. Because (1) the keyboard/mouse based interface limits the user to create 3D objects on a 2D plane; (2) current CAD systems are too complex for conceptual design and require users to be professionally trained. In this paper, we present an innovative rapid 3D conceptual design method based on hand gesture and motion capture system. A unique set of hand gestures for rapid 3D conceptual design based on CSG (Constructive Solid Geometry) was proposed, with the requirement of ease of use and the suitability for real time continuous recognition. Real time hand gesture recognition was realized by static gesture (posture) recognition which is accomplished by skeleton model based template matching, and the dynamic gesture recognition which involves the use of Hidden Markov Models (HMMs). The recognized hand gestures were transformed into OpenSCAD scripting language and then the designed 3D geometry was generated and displayed on the screen. An opinion test was conducted to evaluate the system.