Uncovering the specificities of CAD tools for industrial design with design theory – style models for generic singularity

International audienceAccording to some casual observers, computer-aided design (CAD) tools are very similar. These tools are used to design new artifacts in a digital environment; hence, they share typical software components, such as a computing engine and human-machine interface. However, CAD software is dedicated to specific professionals—such as engineers, three-dimensional (3D) artists, and industrial designers (IDs)—who claim that, despite their apparent similarities, CAD tools are so different that they are not substitutable. Moreover, CAD tools do not fully meet the needs of IDs. This paper aims at better characterizing CAD tools by taking into account their underlying design logic, which involves relying on recent advances in design theory. We show that engineering CAD tools are actually modeling tools that design a generic variety of products; 3D artist CAD tools not only design but immediately produce single digital artefacts; and ID CAD tools are neither a mix nor an hybridization of engineering CAD and 3D artist CAD tools but have their own logic, namely to create new conceptual models for a large variety of products, that is, the creation of a unique original style that leads to a generic singularity. Such tools are useful for many creative designers beyond IDs

A hybrid method for haptic feedback to support manual virtual product assembly

The purpose of this research is to develop methods to support manual virtual assembly using haptic (force) feedback in a virtual environment. The results of this research will be used in an engineering framework for assembly simulation, training, and maintenance. The key research challenge is to advance the ability of users to assemble complex, low clearance CAD parts as they exist digitally without the need to create expensive physical prototypes. The proposed method consists of a Virtual Reality (VR) system that combines voxel collision detection and boundary representation methods into a hybrid algorithm containing the necessary information for both force feedback and constraint recognition. The key to this approach will be successfully developing the data structure and logic needed to switch between collision detection and constraint recognition while maintaining a haptic refresh rate of 1000 Hz. VR is a set of unique technologies that support human-centered computer interaction. Experience with current VR systems that simulate low clearance assembly operations with haptic feedback indicate that such systems are highly desirable tools in the evaluation of preliminary designs, as well as virtual training and maintenance processes. This work will result in a novel interface for assembly methods prototyping, and an interface that will allow intuitive interaction with parts based on a powerful combination of analytical, visual and haptic tools

An approach on 3D digital design: free hand form generation

To sketch is to translate a concept from mind to its first representation. Conventionally, sketching of a three dimensional idea is drawn on paper, or by building a physical model, and then adjusting it into digital translation. The thesis hypothesizes that architects employ tangible interactions to assist design-thinking tasks in early design phases. This thesis suggests another approach on 3D digital design, as a complementary resource for expressing a concept, hence enriching the creative process. A proposal for a new CAD paradigm, based on freehand form generation is detailed here, as well as the development and testing completed during the course of the research. This work describes the required characteristics of this kind of system and discusses the possibilities afforded by this new medium of expression, pointing its strengths and current limitations. The fundamental guidelines to this research were: (1) non-intrusiveness of the input and visualization devices, (2) wireless free hand drawing in 3D space, (3) instinctive interface and (4) exporting capabilities to other CAD systems. In conclusion this work argues that 3D design, based on free hand form generation, allows for an enhancement of the traditional creative process through spontaneous and immediate translation of a concept into 3D digital form

Multiple-view product representation and development using augmented reality technology

Ph.DDOCTOR OF PHILOSOPH

A Novel Haptic Simulator for Evaluating and Training Salient Force-Based Skills for Laparoscopic Surgery

Laparoscopic surgery has evolved from an \u27alternative\u27 surgical technique to currently being considered as a mainstream surgical technique. However, learning this complex technique holds unique challenges to novice surgeons due to their \u27distance\u27 from the surgical site. One of the main challenges in acquiring laparoscopic skills is the acquisition of force-based or haptic skills. The neglect of popular training methods (e.g., the Fundamentals of Laparoscopic Surgery, i.e. FLS, curriculum) in addressing this aspect of skills training has led many medical skills professionals to research new, efficient methods for haptic skills training. The overarching goal of this research was to demonstrate that a set of simple, simulator-based haptic exercises can be developed and used to train users for skilled application of forces with surgical tools. A set of salient or core haptic skills that underlie proficient laparoscopic surgery were identified, based on published time-motion studies. Low-cost, computer-based haptic training simulators were prototyped to simulate each of the identified salient haptic skills. All simulators were tested for construct validity by comparing surgeons\u27 performance on the simulators with the performance of novices with no previous laparoscopic experience. An integrated, \u27core haptic skills\u27 simulator capable of rendering the three validated haptic skills was built. To examine the efficacy of this novel salient haptic skills training simulator, novice participants were tested for training improvements in a detailed study. Results from the study demonstrated that simulator training enabled users to significantly improve force application for all three haptic tasks. Research outcomes from this project could greatly influence surgical skills simulator design, resulting in more efficient training

Human factors considerations for ultrasound induced mid-air haptic feedback

The engineering design process can be complex and often involves reiteration of design activities in order to improve outcomes. Traditionally, the design process consists of many physical elements, for example, clay/foam modelling and more recently Additive Manufacturing (AM), with an iterative cycle of user testing of these physical prototypes. The time associated with creating physical prototypes can lengthen the time it takes to develop one product, and thus, comes at a burdensome financial and labour cost. Due to the aforementioned constraints of the conventional design process, more research is being conducted into applications of Virtual Reality (VR) to complement stages of the design process that would otherwise take and cost a significant amount of time and money. VR enables users to create 3D virtual designs and prototypes for evaluation, thus facilitating the rapid correction of design and usability issues. However, VR is not without its pitfalls, for example, it often only facilitates an audio-visual simulation, thus hindering evaluation of the tactile element of design, which is critical to the success of many products. This issue already has a wide body of research associated with it, which explores applications of haptic (tactile) feedback to VR to create a more realistic and accurate virtual experience. However, current haptic technologies can be expensive, cumbersome, hard to integrate with existing design tools, and have limited sensorial output (for example, vibrotactile feedback). Ultrasound Haptic Feedback (UsHF) appears to be a promising technology that offers affordable, unencumbered, integrable and versatile use. The technology achieves this by using ultrasound to create mid-air haptic feedback which users can feel without being attached to a device. However, due to the novel nature of the technology, there is little to no literature dedicated to investigating how users perceive and interpret UsHF stimuli, and how their perception affects the user experience. The research presented in this thesis concerns the human factors of UsHF for engineering design applications. The PhD was borne out of interest from Ultraleap (previously Ultrahaptics), an SME technology developer, on how their mid-air haptic feedback device could be used within the field of engineering. Six studies (five experimental and one qualitative) were conducted in order to explore the human factors of UsHF, with a view of understanding its viability for use in engineering design. This was achieved by exploring the tactile ability of users in mid-air object size discrimination, absolute tactile thresholds, perception of intensity differences, and normalisation of UsHF intensity. These measures were also tested against individual differences in age, gender and fingertip/hand size during the early stages, with latter stages focussing on the same measures when UsHF was compared to 2D multimodal and physical environments. The findings demonstrated no evidence of individual differences in UsHF tactile acuity and perception of UsHF stimuli. However, the results did highlight clear limitations in object size discrimination and absolute tactile thresholds. Interestingly, the results also demonstrated psychophysical variation in the perception of UsHF intensity differences, with intensity differences having a significant effect on how object size is perceived. Comparisons between multimodal UsHF and physical size discrimination were also conducted and found size discrimination accuracy of physical objects to be better than visuo-haptic (UsHF) size discrimination. Qualitative studies revealed an optimistic attitude towards VR for engineering design applications, particularly within the design, review, and prototyping stages, with many suggesting the addition of haptic feedback could be beneficial to the process. This thesis offers a novel contribution to the field of human factors for mid-air haptics, and in particular for the use of this technology as part of the engineering design process. The results indicate that UsHF in its current state could not offer a replacement for all physical prototypes within the design process; however, UsHF may still have a place in the virtual design process where haptic feedback is required but is less reliant on the accurate portrayal of virtual objects, for example, during early stage evaluations supplemented by later physical prototypes, simply to indicate contact with virtual objects, or when sharing designs with stakeholders and multidisciplinary teams

Factors Affecting Human Force Perception and Performance in Haptic-Enabled Virtual Environments

Haptic technology enables computer users to touch and/or manipulate virtual objects in virtual environments (VEs). Similar to other human-in-the-loop applications, haptic applications require interactions between humans and computers. Thus, human-factors studies are required to recognize the limitations and capabilities of the user. This thesis establishes human-factors criteria to improve various haptic applications such as perception-based haptic compression techniques and haptic-enabled computer-aided design (CAD). Today, data compression plays a significant role in the transmission of haptic information since the efficient use of the available bandwidth is a concern. Most lossy haptic compression techniques rely on the limitations of human force perception, and this is used in the design of perception-based haptic compression techniques. Researchers have studied force perception when a user is in static interaction with a stationary object. This thesis focuses on cases where the human user and the object are in relative motion. The limitations of force perception are quantified using psychophysical methods, and the effects of several factors, including user hand velocity and sensory adaptation, are investigated. The results indicate that fewer haptic details need to be calculated or transmitted when the user's hand is in motion. In traditional CAD systems, users usually design virtual prototypes using a mouse via their vision system only, and it is difficult to design curved surfaces due to the number, shape, and position of the curves. Adding haptics to CAD systems enables users to explore and manipulate virtual objects using the sense of touch. In addition, human performance is important in CAD environments. To maintain the accuracy, active haptic manipulation of the user response can be incorporated in CAD applications. This thesis investigates the effect of forces on the accuracy of movement in VEs. The results indicate that factors such as the base force intensity and force increment/decrement can be incorporated in the control of users' movements in VEs. In other words, we can pull/push the users' hands by increasing/decreasing the force without the users being aware of it

Factors Affecting Human Force Perception and Performance in Haptic-Enabled Virtual Environments

Haptic technology enables computer users to touch and/or manipulate virtual objects in virtual environments (VEs). Similar to other human-in-the-loop applications, haptic applications require interactions between humans and computers. Thus, human-factors studies are required to recognize the limitations and capabilities of the user. This thesis establishes human-factors criteria to improve various haptic applications such as perception-based haptic compression techniques and haptic-enabled computer-aided design (CAD). Today, data compression plays a significant role in the transmission of haptic information since the efficient use of the available bandwidth is a concern. Most lossy haptic compression techniques rely on the limitations of human force perception, and this is used in the design of perception-based haptic compression techniques. Researchers have studied force perception when a user is in static interaction with a stationary object. This thesis focuses on cases where the human user and the object are in relative motion. The limitations of force perception are quantified using psychophysical methods, and the effects of several factors, including user hand velocity and sensory adaptation, are investigated. The results indicate that fewer haptic details need to be calculated or transmitted when the user's hand is in motion. In traditional CAD systems, users usually design virtual prototypes using a mouse via their vision system only, and it is difficult to design curved surfaces due to the number, shape, and position of the curves. Adding haptics to CAD systems enables users to explore and manipulate virtual objects using the sense of touch. In addition, human performance is important in CAD environments. To maintain the accuracy, active haptic manipulation of the user response can be incorporated in CAD applications. This thesis investigates the effect of forces on the accuracy of movement in VEs. The results indicate that factors such as the base force intensity and force increment/decrement can be incorporated in the control of users' movements in VEs. In other words, we can pull/push the users' hands by increasing/decreasing the force without the users being aware of it