Raymond Sung

Automated design process modelling and analysis using immersive virtual reality

The capture of engineering design processes and associated knowledge has traditionally been extremely difficult due to the high overhead associated with current intrusive and time-consuming manual methods used in industry, usually involving interruption of the designer during the design task and relying on them to remember how a design solution was developed after the event. This paper presents novel research which demonstrates how the detailed logging and analysis of an individual designers actions in a cable harness virtual reality (VR) design and manufacturing system permits automated design task analysis with process mapping. Based on prior research, which utilised user-logging to automatically analyse design activities and generate assembly plans, this work involves the automatic capture of extracted design knowledge embedded within the log files and subsequently represented using IDEF0 diagrams, DRed graphs, PSL, XML, annotated movie clips and storyboard representations. Using this design knowledge, an online help system has been demonstrated which helps users to carry out design tasks similar to those performed previously by expert users. This is triggered by monitoring the designers actions and functions in real time and pushes knowledge and advice to the user which was captured from experts and subsequently formalised during earlier design sessions.

Automated design knowledge capture and representation in single-user CAD environments

Current computer-aided design systems excel at recording the final design solution for an engineering problem; however, they are not as adept at capturing the individual designers rationale, knowledge or the process used during the design session. Being able to access this information will give insight into the reasons why key design decisions were made which, in turn, will support engineers who have to make revisions to the product in the future. Therefore, it would be beneficial if CAD systems were able to record design knowledge automatically. The research in this paper attempts to address this issue with a system that unobtrusively captures design processes and design knowledge by logging individual designer behaviour and system interactions while a CAD system is being used; user trials generated around 700 log files that were then analysed to extract these. In addition, various CAD system-independent representations were output to give a visual and formal representation of the processes that occurred. Overall, although carried out within a constrained design environment, this early knowledge capture work demonstrates the potential for automated knowledge capture and subsequent representations within CAD environments as well as the feasibility of design information push.

Cable harness design, assembly and installation planning using immersive virtual reality

Earlier research work using immersive virtual reality (VR) in the domain of cable harness design has shown conclusively that this technology had provided substantial productivity gains over traditional computer-aided design (CAD) systems. The follow-on work in this paper was aimed at understanding the degree to which various aspects of the immersive VR system were contributing to these benefits and how engineering design and planning processes could be analysed in detail as they are being carried out; the nature of this technology being such that the user’s activities can be non-intrusively monitored and logged without interrupting a creative design process or a manufacturing planning task. This current research involved the creation of a more robust CAD-equivalent VR system for cable harness routing design, harness assembly and installation planning which could be functionally evaluated using a set of creative design-task experiments to provide detail about the system and users’ performance. A design task categorisation scheme was developed which allowed both a general and detailed breakdown of the design engineer’s cable harness design process and associated activities. This showed that substantial amounts of time were spend by the designer in navigation (41%), sequence breaks (28%) and carrying out design-related activities (27%). The subsequent statistical analysis of the data also allowed cause and effect relationships between categories to be examined and showed statistically significant results in harness design, harness design modification and menu/model interaction. This insight demonstrated that poorly designed interfaces can have adverse affects on the productivity of the designer and that 3D direct manipulation interfaces have advantages. Indeed, the categorisation scheme provided a valuable tool for understanding design behaviour and could be used for comparing different design platforms as well as examining other aspects of the design function, such as the acquisition of design decision intent. The system also demonstrated the successful automatic generation of cable harness assembly and cable harness installation plans from non-intrusive user-system interaction logging, which further demonstrates the potential for concurrent design and manufacturing planning to be carried out.

Haptic virtual reality assembly – Moving towards Real Engineering Applications

The use of virtual reality (VR) in interactive design and manufacture has been researched extensively but its practical application in industry is still very much in its infancy. Indeed one would have expected that, after some 30 years of research, commercial applications of interactive design or manufacturing planning and analysis would be widespread throughout the product design domain. Similarly, investigations into virtual environments (VE) for assembly and disassembly tasks have been carried out for many years. Given the availability of moderately-priced high performance computing technology, many of these virtual manufacturing interfaces which only stimulate the visual senses – have made actual physical contact during product development an increasingly rare occurrence.

The application of ubiquitous multimodal synchronous data capture in CAD

Design is an interactive and iterative process where the designers skills and knowledge are fused with emotive rationales aided by design tools. A design solution is thus influenced by the designers creativity, experience and emotional perception. Consequently, there is a need within computer aided design (CAD) research for ubiquitous tools to capture the affective states of engineers during design activities to further understand the product design process.This paper proposes a generic framework for ubiquitous multimodal synchronous data capture, based around the capture of CAD system activities, to monitor and log a variety of inputs, interactions, biophysical data and design solutions with a view to providing meta and chronological performance data for post design task analysis. The framework has been employed in two use cases namely, a CAD station activity and a collaborative design review. The results of these trials validated the architecture and use of the ubiquitous data capture approach demonstrating the practical application of time-phased data capture, analysis and the subsequent output of metadata in CAD environments providing a new perspective on, and a new way of investigating CAD-based design activities.This research also extrapolates the frameworks usefulness into future CAD and PLM systems by arguing why and how they need to adopt such ubiquitous platforms. It also subjectively points to potential opportunities and issues that might arise when implementing the ubiquitous multimodal metadata architecture in a real-life environment. A generic ubiquitous data capture framework is demonstrated via two case studies.Variety of inputs, interactions, biophysical data and design solutions are captured.Tight temporal synchronisation with commodity data logging tools is achieved.Demonstrates engineering knowledge capture linking CAD and PLM via generated metadata.The frameworks use in future CAD and PLM systems is extrapolated.

The development of an integrated haptic VR machining environment for the automatic generation of process plans

In modern manufacturing it is crucial to be able to produce a product right first time, as efficiently as possible. Virtual prototyping can play a key part in fulfilling this requirement, allowing the simulation of production in advance without the need for unnecessary downtime, material waste or increased lead times. This makes virtual reality (VR) potentially an ideal planning tool since, with each simulation, a better understanding of requirements can be reached and a more effective solution found. This application of haptic virtual reality is particularly relevant in the field of machining where both material and resource costs are high. Planning for the machining of a product requires an intricate knowledge of materials, processes and machining methods. Intuitive virtual reality interfaces can provide new, engineer-friendly means of generating such manufacturing sequences. Current research in haptic virtual reality focuses on specific individual aspects of machining such as path planning or simulation for training; however, in order to simulate multi-operation machining with a view to generating practical and usable process plans, in which there are several processes involved in bringing a product to fruition; an approach is required which allows this type of functionality. This paper presents such a haptic virtual process planning system that allows an operator to load and set up a billet for machining, set up, sequence and tear down any combination of milling, drilling or turning operations then produce a time-estimated process plan. All of the human expertise captured during this process is logged and parsed to generate the final instructions including operation times, tool lists, operation lists and route sheets in easy-to-read format. Via three planning examples, the generation of process plans is demonstrated; with these subsequently validated through their use by a shop floor machinist who utilised them to produce the parts, and a comparison to previously existing plans for the same parts.

Automated generation of engineering rationale, knowledge and intent representations during the product life cycle

One of the biggest challenges in engineering design and manufacturing environments is the effective capture of and decoding of tacit knowledge. Fundamental to Life Cycle Engineering is the capture of engineering information and knowledge created at all stages of the product development process, from conceptual design through to product support and disposal. Consider this—the amount of vital information and knowledge lost when key design personnel retire—hence the need to capture meta-cognitive task-related strategies, particularly to support knowledge reuse and training. Many methods have been tried and tested with the successful few found to be very time consuming and expensive to implement and carry out; consequently, there is a need to investigate alternative paradigms for knowledge and information capture. This paper reports on a current industrial case study on knowledge capture methods employed by industrial partners in the design and manufacture of a variety of electro-mechanical products. The results suggest the need for new kinds and forms of knowledge capture methods and representation, particularly those associated with individual design engineering tasks. Following the findings, the paper presents a knowledge capture methodology for automatic real-time logging, capture and post-processing of design data from a virtual reality design system. Task-based design experiments were carried out with industrial partners to demonstrate the effective, unobtrusive and automatic capture and representation of various forms of design knowledge and information. Qualitative and quantitative evaluation of knowledge representations were also performed to determine which method was most effective at conveying design knowledge and information for other engineers.

Interpreting Three-Dimensional Shape Distributions

Abstract Effective content-based shape retrieval systems would allow engineers to search databases of three-dimensional computer-aided design (CAD) models for objects with specific geometries or features. Much of the academic work in this area has focused on the development of indexing schemes based on different types of three-dimensional to two-dimensional ‘shape functions’. Ideally, the shape function used to generate a distribution should be easy to compute and permit the discrimination of both large and small features. The work reported in this paper describes the properties of three new shape distributions based on computationally simple shape functions. The first shape function calculates the arithmetic difference between distributions derived (using the original D2 distance shape function) from both a three-dimensional model and its convex hull. The second shape function is obtained by sampling the angle between random pairs of facets on the object. The third shape function uses the surface orientation to filter the results of a distance distribution. The results reported in this paper suggest that these novel shape functions improve significantly the ability of shape distributions to discriminate between complex engineering parts.

3D Object Representation for Physics Simulation Engines and its Effect on Virtual Assembly Tasks

Physical based modelling (PBM) uses physics simulation engines (PSE) to provide the dynamic behaviour and collision detection of virtual objects in virtual environments emulating the real world. There exists a variety of PSEs, each one with pros and cons according to the application in which they are employed. Each physics engine uses its proprietary collision detection algorithm. Collision detection is a key aspect of assembly tasks and its performance is dependent on the way virtual objects are represented. In general, objects can be divided into two groups: convex and concave, the latter being the most common and challenging for collision detection algorithms. This study reports on three different methods to represent concave objects. GIMPACT, Hierarchical Approximate Convex Decomposition (HACD) and Approximate Convex Decomposition (ACD), which are evaluated and compared based on their collision detection performances. An exact convex decomposition algorithm, named as ConvexFT, is also proposed and analyzed in this paper. Finally the performance of the three existing methods and the ConvexFT proposed approach are compared in order to assess which model representation algorithm is best suited for haptic-virtual assembly tasks.Copyright

Assembly planning and motion study using virtual reality

Carrying out assembly process planning tasks manually is both time-consuming and requires a lot of effort. Due to this, a great deal of research has been carried out on computer-aided process planning (CAPP) and computer-aided assembly planning (CAAP) systems. This paper presents two virtual tools called COSTAR (Cable Organisation System Through Alternative Reality) and HAMMS (Haptic Assembly, Manufacturing and Machining System) that both have an assembly planning capability. To gain an insight into the processes that occur during a design and assembly task, two time and motion study methods called therbligs and chronocyclegraphs have been utilised in both virtual tools to carry out the investigation. In addition, a brief investigation has been carried out to examine the time savings of using the virtual tools in comparison with the traditional manual method.Copyright