Basavaraj Tonshal

Geometric Surface Features Applied to Volumetric CAE Mesh Models

In this paper, we discuss a way to extend a geometric surface feature framework known as Direct Surface Manipulation (DSM) into a volumetric mesh modeling paradigm that can be directly adopted by large-scale CAE applications involving models made of volumetric elements, multiple layers of surface elements or both. By introducing a polynomial-based depth-blending function, we extend the classic DSM mathematics into a volumetric form. The depth-blending function possesses similar user-friendly features as DSM basis functions permitting ease-of-control of the continuity and magnitude of deformation along the depth of deformation. Practical issues concerning the implementation of this technique are discussed in details and implementation results are shown demonstrating the versatility of this volumetric paradigm for direct modeling of complex CAE mesh models. In addition, the notion of a model-independent, volumetric-geometric feature is introduced. Motivated by modeling clay with sweeps and templates, a model-independent, catalog-able volumetric feature can be created. Deformation created by such a feature can be relocated, reoriented, duplicated, mirrored, pasted, and stored independent of the model to which it was originally applied. It can serve as a design template, thereby saving the time and effort to recreate it for repeated uses on different models (frequently seen in CAE-based Design of Experiments study).Copyright

A Mesh Feature Paradigm for Rapid Generation of CAE-Based Design of Experiments Data

CAE-Based simulation and Design of Experiments (DoE) are becoming mature and increasingly effective in development of complex industrial products such as automobiles. We present in this paper a CAE mesh-modeling paradigm that ultimately led to fast, automatic generation of a family of meshes based on a base design. This paradigm is hinged on the so-called mesh features to achieve productivity for modeling CAE meshes. Mesh features are self-contained mesh deformation operations that are context-free, stored separately from the base model, and can be applied to the model in a proper mix at any time. Libraries of mesh features can also be established to archive useful features for future use. Furthermore, by assigning mesh features for DoE factors, one can specify for the system the proper way to assemble features and apply them automatically to the base model to generate input meshes for a DoE study. Automatic generation of a family of DoE input meshes results in maximum time savings and minimum chances for errors, especially for applications involving large-scale CAE models.Copyright

RAVEN: Improving Interactive Latency for the Connected Car

Increasingly, vehicles sold today are connected cars: they offer vehicle-to-infrastructure connectivity through built-in WiFi and cellular interfaces, and they act as mobile hotspots for devices in the vehicle. We study the connection quality available to connected cars today, focusing on user-facing, latency-sensitive applications. We find that network latency varies significantly and unpredictably at short time scales and that high tail latency substantially degrades user experience. We also find an increase in coverage options available due to commercial WiFi offerings and that variations in latency across network options are not well-correlated. Based on these findings, we develop RAVEN, an in-kernel MPTCP scheduler that mitigates tail latency and network unpredictability by using redundant transmission when confidence about network latency predictions is low. RAVEN has several novel design features. It operates transparently, without application modification or hints, to improve interactive latency. It seamlessly supports three or more wireless networks. Its in-kernel implementation allows proactive cancellation of transmissions made unnecessary through redundancy. Finally, it explicitly considers how the age of measurements affects confidence in predictions, allowing better handling of interactive applications that transmit infrequently and networks that exhibit periods of temporary poor performance. Results from speech, music, and recommender applications in both emulated and live vehicle experiments show substantial improvement in application response time.

A Novel Approach to the Design and Development of an Interactive Learning App for Automotive IVI Systems

Since its launch Ford SYNC™ with MyFord Touch™ in-vehicle infotainment (IVI) system has migrated to many vehicle programs and had multiple software updates, which presented Ford dealers with the ever-increasing challenge of training new owners effectively and efficiently. This paper presents the design, architecture and implementation of “MyFord Touch Guide”, a novel, cross-platform mobile app that delivers a unique MyFord Touch learning and familiarization experience for dealers and consumers alike. This app incorporates the production MyFord Touch graphical user interface for an interactive learning experience. Additionally, it integrates a host of video tutorials featuring a computer-animated character, which offers an insightful, personalized and self-guided tour experience of the essential features and functions of the system. MyFord Touch Guide is a cross-platform app and based on a “hybrid” app architecture that uses both native mobile and web technologies. Feedback gathered from multiple nation-wide surveys indicates that the proposed approach provides a highly effective and scalable solution towards developing a diverse range of cross-platform, interactive, mobile learning apps.Copyright

High Performance Dirichlet Parametrization Through Triangular Bézier Surface Interpolation for Deformation of CAE Meshes

We present a method that extends the physics-based Dirichlet parametrization for applications concerning deformation of CAE meshes. Developed for a geometric surface feature framework called Direct Surface Manipulation, Dirichlet parametrization offers a number of operational flexibilities, such as its ability to use a single polynomial blending function to control deformation of a surface region subject to multiple user-specified displacement conditions. Dirichlet parametrization considers the domain of deformation as 2D steady-state conductive heat flow and solves for unique temperature distribution over the deformation domain using the finite element analysis (FEA) method. The result is used for evaluation of the polynomial blending function during surface deformation. The original Dirichlet parametrization, however, suffers from two limitations. First, because the 2D FEA mesh required for solving the steady-state heat transfer problem is obtained by directly projecting the affected 3D mesh onto a plane (deformation domain), both parameterization quality and performance depend on the structural characteristics of the projected 2D mesh (type of elements, node density, etc.) rather than geometrical characteristics of the deformation domain. Second, projecting a 3D mesh to create a 2D FEA mesh can be problematic when multiple areas of a 3D mesh are projected on the plane and overlap each other. Improvement techniques are presented in this paper. Instead of projecting the 3D mesh onto the plane to form the 2D FEA mesh, an auxiliary mesh is created based on geometric characteristics of the deformation domain, such as its size and boundary shape. Delaunay triangulation with an area constraint is applied in meshing the deformation region. The result is used as the 2D FEA mesh for solving the steady-state heat flow problem using the finite element method. Temperature of an affected node of the 3D mesh is obtained by interpolation in two steps. First, the node is projected onto the 2D FEA mesh, and the intersecting triangle is found. Second, the temperature at the intersection is obtained by interpolating the temperatures at the three vertices of the triangle using the cubic, triangular Bezier interpolant. The result is equated to the temperature of the node. The use of an auxiliary mesh eliminated mesh-dependency for Dirichlet parametrization. The use of triangular cubic Bezier interpolant results in better continuity condition of the interpolating surface between adjacent elements than linear interpolation. This allows us to employ a moderate size FEA mesh for computational efficiency. Implementation of the method is discussed and results are demonstrated.Copyright

Determine Mesh Orientation by Voxel-Based Principal Component Analysis

In this paper we propose a new method to determine the part orientation of a 3D mesh based on Principal Component Analysis (PCA). Although the idea and practice of using PCA to determine part orientation is not new, it is not without practical issues. A major drawback of PCA, when it comes to dealing with meshes comprised of nodes and elements, is that the results are tessellation-dependent because of its sensitivity to variability. Two CAE meshes derived from the same CAD model but with different mesh node distribution characteristics, for instance, can yield different principal components. This is an undesirable outcome because the primary concern in model reorientation is shape, not the representational details of the shape. In order to reduce the influence of node characteristics, weight factors were proposed in the past, but the improvement is limited. To overcome this limitation, we must eliminate the influence of mesh node distribution. We achieve this by introducing an intermediate workspace, which is subsequently voxelized. We then find the intersection of the mesh model with the voxelized workspace. We collect the intersecting voxels to form an intermediate, tessellation-independent representation of the mesh. Applying PCA to this “neutralized” representation allows us to achieve mesh-property-independent results. The voxel representation also provides an opportunity of computational efficiency. We implemented an octree data structure to store the voxels and implemented a fast intersection (between a mesh element and a voxel) check procedure utilizing the interval overlap check derived from the separating axis theorem. Practical issues concerning determination of the voxel space resolution is addressed. A two-step trial and correction approach is proposed to enhance the consistency of results. Our voxel-based PCA is robust, fast, and straightforward to implement. Application examples are shown demonstrating the effectiveness and efficiency of this approach.Copyright

Develop Pleasurable Automotive Switch-Feel Through Perceptual Design

Automotive interior has become the next battleground for quality, customer satisfaction and emotional appeal. As an integral part of vehicle interior, operating quality of switches has a direct impact on the customer’s overall perception of quality. As of today, work in switch design and engineering has focused primarily on visual appeal, ergonomics and functionality while limited work has been done to understand and design switches that “feel” pleasurable to operate. As a result, specifications concerning the switch-feel are incomplete or ineffective and our automotive switches typically lack good and consistent operating feel. Switch-feel “quality” is affected by how sensory input is processed by the user, and as such, it falls into the category of perceptual quality. To effectively meet the challenge of engineering high quality switch-feel we present a novel approach based on perceptual design. With perceptual design the sensory pleasure of a product is considered as a forefront design objective rather than a bi-product of the traditional functionality and usability centered product design and development practice [1]. Our methodology employs several well-established science and engineering disciplines to gain knowledge of perceptual data, its relationship with physical stimuli, and the human sensitivity to such physical stimuli. Haptics simulators were developed to generate a wide range of switch-feel for use in our psychophysical studies. Multi-Dimensional Scaling (MDS) was used to identify the main components of human perception of switch-feel. Threshold analysis was carried out to determine how sensitive humans are in detecting changes of these parameters. A Design of Experiment (DOE) preference study was used to develop “Quality Functions” that map switch-feel physical parameters to subjective, perceived quality. New switch-feel specifications were created based on our perceptual design work. A switch-feel measurement system was also developed to verify whether the feel of a physical switch actually meets our specifications. We applied perceptual design to a production vehicle program to improve the operating feel of its climate control switches. The results demonstrated that it was effective in delivering good, pleasurable switch-feel, and at the same time, improved our engineering efficiency.Copyright

A Recursive, Line-Intersection Method for Finding the Area of a Mesh Projected Onto a Plane

In this paper, we describe a new approach for computing the area of a mesh projected onto a plane. This approach utilizes the graphics hardware’s line/object intersection capability and a recursive subdivision strategy to achieve performance and precision control. This approach starts from digitizing the projection plane into a grid of rectangular elements. For each element the graphics engine is utilized to check whether projection lines passing through the nodes of the element intersect the object in the model space. If all lines intersect the object, the element is considered “inside” and its area will be accounted towards the final projection area. If none of the lines has an intersection, the element is considered “outside” and discarded. For those elements that lay along the boundary of the projected area (which means some of their lines intersect the model while others don’t) we subdivide them until they are sufficiently small and the given area tolerance is met. Heuristics are derived for deciding the initial grid resolution and the level of subdivisions needed to meet/exceed a given area tolerance. Implementation results are demonstrated and compared with a classic polygon-clipping approach.Copyright