Casper Wickman

Increased Concurrency between Industrial and Engineering Design Using CAT Technology Combined with Virtual Reality

These days, when an industrial design concept is evaluated in an aesthetic manner, all models used are nominal. If the design is evaluated with nominal models, variation aspects and design solutions that would greatly influence the overall quality appearance might not be discovered until the first test series are made. By using nonnominal models during the design process, important geometric aspects can be issued, and the need for physical test series can be reduced. In the automotive industry, especially in body design, the relationships between doors, hoods, fenders and other panels are critical for quality appearance. This article suggests how combining traditional Computer Aided Tolerance (CAT) tools with modern Virtual Reality (VR) tools has the potential to enhance concurrency between industrial and engineering design and provide support for the geometry process in early phases. Traditional nonnominal verification can then already be conducted in the concept phase using digital models instead of physical. A VR-CAT tool supported geometry design process is proposed from a holistic point of view. Results and indications from a case study, where prescribed VR-CAT tool has been tried out in an on going project at Volvo Cars is presented.

Perception of gap and flush in virtual environments

This paper presents results from an experiment with the aim to screen 10 parameters that could have an impact on how distance is judged in virtual environments when evaluating the visual quality appearance of industrial design concepts in the automotive industry. In order to reduce the number of experimental runs, a D-optimal design was used. The difference in the two responses in gap distance and the difference in flush distance (denoted DeltaFlush) was investigated. The results from the study show that the two most significant effects for DeltaGap are viewing mode and type of split line. The two most significant effects for DeltaFlush are gap and flush. In order to reduce the error in distance judgement, the gap should be evaluated in a stereographic view combined with texture, Clear Coat, similar colours, and a full model. Flush should be evaluated with a small distance of the gap on the same split line, similar colours of parts and with a full model. The next step is to validate the results by configuring the virtual environment in accordance with the result and perform a similar evaluation with the same group of participants.

Toward non-nominal virtual geometric verification by combining VR and CAT technologies

As the markets are becoming increasingly competitive and customer demands higher, virtual verification has become an important tool to cut cost and to shorten lead-time. So far, the main focus area for Virtual Reality (VR) tools has been to extend and support concurrent engineering between manufacturing and design in early stages of the design process. Today, when a styling concept of an artifact is evaluated in an esthetic manner, all models used are nominal. Variational aspects and design solutions, that greatly will influence the over-all quality appearance, will not be discovered until the first test series are made. By using non-nominal models during all stages of the design process, important geometric aspects can be issued and the needs for physical test series can be reduced. In the automotive industry, especially within body design, the relations between doors, hoods, fenders and other panels are critical. Today the quality appearance of vehicle is judged by these relations.

A Framework for Non-nominal Visualization and Perceived Quality Evaluation

Perceived Quality clusters different aspects that influence the customers perception of non-functional quality on a product that are perceive through senses. All together those aspects and the harmony between them reflect the producers ability to control product parameters and thereby also mirror the functional quality of the product. High Perceived Quality can not be added to the product at the end of the developing process. Project prerequisites, system solution, factory capability etc. are criterion to succeed. Therefore, it is important to be able to evaluate Perceived Quality early in the process when product system solutions and architecture are defined, although data maturity is low. This paper presents a comprehensive framework to manage and support evaluation of Perceived Quality aspects in a product development process. The framework is based on an industrial process in combination with recent research within the field. The framework focus on activities that can be performed at different stages in the developing process based on maturity of the CAD or styling data. For example, if the styling data is divided into different components by split-lines it has reached higher level of maturity then styling data that not has been divided. Consequently, the choice of applied method is based on data maturity, regardless phase in the developing process. The framework contain methods based on several different simulation and analysis techniques. Both design methods, Computer Aided Tolerancing and FEA based non-rigid variation simulation are represented in the framework.

Influence of rigid and non-rigid variation simulations when assessing perceived quality of split-lines

Non-nominal visualisation is used to evaluate how geometrical variation influences the appearance of split-lines between components on a car body. Depending on the simulation method, visualised variation can be represented in an unrealistic manner, which can affect the perception of the result. This paper presents a comparative study in which eye-tracking equipment has been used in order to explore whether the interpretation of variation differs between rigid- and non-rigid-based variation simulations during the evaluation of visualised models. Subjects from the automotive industry were asked to evaluate two virtual models where the same amount of variation was represented by rigid and non-rigid models. Eye tracking was used to record how the subjects performed the assessment. The result shows that there is a significant difference in how simulation results are interpreted using rigid versus non-rigid simulation.

Non-Rigid Behavior Prediction Based on Styling Data for Evaluation of Perceived Quality

In the automotive industry it is of great importance to manage the impact of part and assembly variation as it affects aesthetical aspects of the final Perceived Quality, such as the appearance of flush, parallelism and gaps in split-lines. By using a CAT (Computer Aided Tolerancing) software simulating tolerances, in combination with a high-end visualization tool, evaluations are made to judge a predicted outcome of the final Perceived Quality. When a new styling concept needs to be evaluated the data used for analysis and visualization will be less mature and the fact that several vehicle components are non-rigid will further complicate the realization of non-nominal visualization. The deformation behavior of non-rigid components is dependent on several parameters such as part shape, position of reference points, flanges, reinforcements etc. Such information is most likely not available when evaluating a new styling concept, represented only by a surface skin. This paper discusses the possibility to use this limited information, defined as styling data, as a basis when performing non-nominal visualization and evaluation of Perceived Quality based on deformable non-rigid components. The insufficient information is supplemented by collecting and comparing data from prior projects to enable non-rigid behavior prediction of components as such.© 2009 ASME

Towards Non-FEA-Based Deformation Methods for Evaluating Perceived Quality of Split-Lines

In the automotive industry, the evaluation of Perceived Quality of split-lines is strongly dependent on simulation and visualisation activities to analyse consequences of geometrical variation. A truthful representation of the part behaviour is therefore essential. Moreover, variation simulation of non-rigid parts is today performed by finite element analysis (FEA). FEA-based methods demand meshed models that correspond to the final engineering design to calculate the correct stiffness matrix. However, geometrical models in early phases have significantly lower level of detail. Approximate methods are therefore considered as options to better deal with this restriction. In this paper, an approximate non-FEA-based simulation method, based on a mesh morphing approach, has been the subject of a case study to evaluate its acceptance and applicability. It involved a focus group and individual interviews with engineers and project managers from two companies within the automotive industry. The study shows that providing the possibility to perform visualisation activities in the early phases is highly sought after, both on an engineering level and on a management level. Furthermore, a number of application scenarios for this type of approximate method were proposed. The study also identified strengths and risks of visualising the effects of geometrical variation in this way.

Comparison of Non-Nominal Geometry Models Represented in Physical Versus Virtual Environments

In the automotive industry today, virtual geometry verification activities are conducted with nominal models in the early design phases. Later in the design process when the first physical test series are made, are concepts verified in a non-nominal manner. Errors detected at this stage can result in expensive post-conceptual changes. By combining Computer Aided Tolerance (CAT) simulation tools with Virtual Reality (VR) tools, virtual environments for non-nominal geometry verification can be utilized. This paper presents the results from a study, conducted at Volvo Cars, that investigates the perceptional aspects that are related to verification of quality appearance, using non-nominal virtual models. Although a realistic non-nominal model is created, the interpretation, i.e. how the model is perceived, must be clarified. This would represent a validation of the model from a perceptional point of view. Since the effect of geometric variation is a specific application, with high demands on realistic and detailed representation, perceptional studies are needed to ensure that VR and other virtual representations can be used for this kind of application. The question is whether it is possible to evaluate aspects like flush, gap and see-through in virtual environments. In this paper, two environments are compared, one physical and one corresponding virtual environment. Three adjusted physical vehicles are mapped to the virtual environment and compared using non-immersive desktop VR in a visualization clinic with test subjects from the automotive industry. The study indicates that virtual objects are judged as less good looking compared with physical objects. There is also a higher degree of uncertainness when judging virtual objects.

Perceived quality and the core values in the automotive industry: A corporate view

This study explores how professionals from the Volvo Car Group and Volvo Group Truck Technology understands their company’s core values and transfers these into perceived quality attributes. Traditionally, both of the companies share the same core values: Quality, Safety, Environmental Care, but they transform these values in different ways due to different customer needs. In general, technical quality has been one of the key features in the automotive industry premium segment for many years, but in recent years, it has shifted from being the primary purchasing criterion into being a basic requirement. Today, maintaining a forefront position in the premium segment of the car industry can only be achieved by delivering products that are perceived by the customers as high-quality products. Perceived quality becomes a cutting edge in the competition between car manufacturers. The purpose of this study is to investigate emerging industry trends and make steps towards elicitation, objectification and distribution of issues regarding perceived quality.

Non-FEA-Based Method as Means for Knowledge Based Assessment of Perceived Quality

Fit and finish of vehicle split-lines is one important contributor to the final Perceived Quality (PQ) of the product. To achieve high PQ of split-lines, effects of geometrical variation has to be considered. In early phases of the development chain the geometry models used for simulation and visualization have low level of detail. This limits the possibility to perform certain simulations that rely on a more complete detailed design. Consequently, alternative methods have to be considered to predict and simulate possible outcome in early phases concerning PQ issues. This paper proposes how an existing non-FEA-based deformation method can support virtual assessment of the PQ of split-lines in early phases. The method is based on mesh morphing and has been implemented in a CAT-tool (Computer-Aided Tolerancing). Its strength lies in the simplicity of generating deformed shapes. The paper specifically focuses on how available knowledge regarding issues from previous projects can be used as input to the method, to predict part deviation and part behavior. The paper further presents industrial examples where the method has been applied. The results show that the proposed technique can be used as a complement to other simulation tools in early phases, where low level of detail on geometries limits the possibility to perform FEA (Finite Element Analysis) based simulations.