Showing papers by "Yonghua Chen published in 2004"

Towards a haptic virtual coordinate measuring machine

Abstract: In this paper, a novel coordinate measuring machine (CMM) inspection path planning environment, named haptic virtual coordinate measuring machine (HVCMM), is proposed, which makes use of haptic modeling technique for CMM off-line programming. HVCMM is an accurate model of real CMM, simulating a CMM’s operation and its measurement process in a virtual environment with haptic perception. It enables CMM off-line programming to take place exactly as if an operator were in front of a real CMM and moving a real CMM probe. To generate the inspection path of a part, teach pendant programming is made by pointing a probe at the 3D computer-aided design (CAD) model of a part using a haptic device. With the HVCMM system, it is much easier to generate collision-free probe path than using other off-line inspection planning methods. Furthermore, when a contact occurs between the CMM and the object, a force is generated based on a proposed mechanics model besides visually showing the contact in the HVCMM environment. Surface voxel is used for quick collision detection. The HVCMM not only facilitates the inspection path planning, but also speeds it up. The proposed HVCMM can also be used for the training of CMM operation.

Haptic rendering based on spatial run-length encoding

Abstract: In this paper, an extendable volumetric representation based on run-lengths called spatial run-length encoding (S-RLE) is presented. The S-RLE representation is developed for a haptic shape modeling system that is based on simulated machining processes. In the system, shape modeling is simulated as virtual material removal processes similar to machining processes with volume-based haptic rendering. The object and the tools are represented by S-RLE. The data structure of S-RLE consists of two cross-referenced databases: one is a stack of lists in geometrical domain, recording the runs describing the space occupation of the object; the other is a table in physical domain, describing the physical properties of each element. The latter is extendable to include more diverse physical properties such as parts composed of heterogeneous materials. Algorithms for geometric operations and haptic rendering based on S-RLE are developed. The proposed S-RLE data structure has the features of efficient memory usage, quick collision detection, inherent representation for heterogeneous objects, and fast visual rendering. Copyright 2003 Elsevier Ltd.

Haptic Modeling in Rapid Product Development

Abstract: This paper presents an integrated product development platform. Haptic modeling, due to its growing applications to different aspects of product development, is envisioned as the core technology for the proposed rapid product development platform. Since haptic modeling is developed based on physical laws, it is anticipated as the natural link between the virtual world and practical applications. In the proposed platform, haptic devices are used as the central mechanisms for reverse engineering, shape modeling, virtual prototyping, machining tool path planning and tolerance inspection path planning. The hardware system is constructed by attaching a digitizing probe to a haptic device Phantom®. This configuration enables the force guided digitization in reverse engineering. When a three dimensional computer model is constructed by either haptic shape modeling or reverse engineering, both tool path planning and coordinate measuring machine (CMM) tolerance inspection path planning can be carried out i...

Reverse engineering based on virtual volume sculpting

Abstract: This paper presents a novel reverse engineering methodology that is based on volume removing. Given a physical model, virtual clay in which the model can be embedded is generated in the computer with the help of a fixture. The virtual clay is represented by voxel arrays and the dimension of the virtual clay is defined based on the bounding box of the model. When digitizing, a three dimensional position tracker is moved around the physical model in a freehand manner by the user. The movements of the tracker are reflected by its counterpart in the computer: a virtual tracker. The swept volume of the virtual tracker will be removed from the virtual clay. When no more virtual clay can be removed, the remained part of the virtual clay is a volume representation of the physical model. The tracker used in this paper is a probe attached to a six degree of freedom (6DOF) haptic device. Physical constraints and virtual constraints are coupled in the system. The strength and weakness of the presented method are analyzed and the applicability is discussed.

Haptic aided ergonomic evaluation in mass customized product design

Abstract: Under the pressure of market competition, there is a tendency for product developers to change their strategy from mass production to mass customization. Ergonomics is an important concern in a successful product development. Ergonomic satisfaction should be one of the variants in mass customization. However, ergonomics factor is not emphasized as strongly as visual factors, such as shape, color, texture, etc. One of the reasons is that ergonomic characteristics are difficult to be presented to the end users in contrast to those visual properties. This paper highlights the role of ergonomics in the product design for mass customization and provides an approach to customer oriented ergonomic evaluation by introducing haptic rendering techniques. With a force feedback device, coupled with a visual feedback device - display, consumers can evaluate not only the form of the product, but also the physical properties, such as stiffness and tactile feel before they make a customized decision. Through cases studies, a prototype platform of haptic aided ergonomic evaluation for mass customized product design is demonstrated.