Human factors and ergonomics

Clothing is the most intimate artefact that interacts with both body and society. Over the past quarter century, with the introduction of new technologies, people are experiencing unprevented changes in their behaviours and way of living. Technology is becoming a large part of daily life and its unchecked influence has many emotional consequences, many of which are overlooked. The aim of this research is integrating textiles with new technologies to create garments that provide new social interactions and avenues for emotional expression. The experimental project has been done to explore new possible interaction scenarios through wearable technologies by turning an intangible phenomenon, emotion, to a tangible artefact. The paper refers to the research question: 'How can an intangible fact, which is known as existing but doesn't have a physical matter, emotion, be embodied and transmitted through technology?' by means of a theoretical study on wearable technologies and its role in emotional communication, following with an experimental project carried out as both virtual and real prototypes. This paper not only focuses on the prototyping process, but also addresses the user experience during the interaction by various user perception tests. © 2011 ACM.

Keywords: emotion , intangible , mediation , social interaction , wearable technologies

Due to the huge impact of communication technologies, the meaning of social existence is changing towards the use of electronic devices as extensions of senses. While technology is becoming intimate, reaching farther into user's lives than ever before, wearable technology has emerged as a new research field where technology is worn to provide a sensory interface. Through the integration of technology and garments, the research aims to discover new ways of creating wearables that provide new avenues for emotional expression and social interaction. Emotional embodiment through Wearable Technology can strengthen social bonds through a paradigm of increased emotional expression, understanding, and trust. To verify this hypothesis, a set of dynamic garments has been built by developing both virtual and real prototypes and performing user tests. This paper addresses to new scenarios of sensing, interacting, and interpreting emotions through Wearable Technology and its' effects on the user's perception. © 2011 by ASME.

The paper describes a novel 3D interaction technique based on Eye Tracking (ET) for Mixed Reality (MR) environments. We have developed a system that integrates a commercial ET technology with a MR display technology. The system elaborates the data coming from the ET in order to obtain the 3D position of the user's gaze. A specific calibration procedure has been developed for correctly computing the gaze position according to the user. The accuracy and the precision of the system have been assessed by performing several tests with a group of users. Besides, we have compared the 3D gaze position in real, virtual and mixed environments in order to check if there are differences when the user sees real or virtual objects. The paper also proposes an application example by means of which we have assessed the global usability of the system. © 2011 by ASME.

Over the past decade, researchers have investigated AR as a promising candidate technology for building advanced interfaces for maintenance personnel. Nevertheless, the low usability of cumbersome hardware, the need to use markers, and the complexity of creating digital content seem to hinder AR's effective implementation in industry. This prototype system aims to demonstrate that you can implement AR to support aircraft maintenance personnel. To meet a daily inspection procedure's operational requirements, the system employs markerless pose estimation. © 2006 IEEE.

Keywords: aircraft maintenance , augmented reality , computer graphics , graphics and multimedia , human-computer interaction

We present a novel self-calibrating wearable device to improve running training by active vibro feedback. The system consists of a pair of spandex shorts embedding: a processor unit, 2 three-axial accelerometers, 2 vibro motors, a SD card reader\writer module and a real time clock. Two supplementary wireless accelerometers are located on the shoes. We present an algorithm to compute gait asymmetry from the four sensors data. The main novelty is the auto calibration algorithm which uses principal component analysis on each sensor based on kinematic assumptions. The system provides two important advantages: data logging and real time active correction. The active correction is performed sending signals to the user in real time via vibrations cells (rumble feedback). The vibration signals are sent to the specific leg and its intensity is proportional to the entity of required correction. This training system for running can be very useful to athletes and to sport medicine in order to improve speed, posture, fatigue and reduce joints osteoarthrotic problems.

Keywords: Active posture correction , Running training , Vibro feedback , Wearable wireless device

The main objective of this works is to develop a wearable device to improve sport training in lower limb. The system consists of a pair of spandex shorts which embed a processor unit, 2 accelerometers, 2 vibro motors, a SD card reader\writer module and a real time clock. The accelerometers are located in proximity to the knees and are used to measure in real time the tri-axial accelerations for each leg. We present a novel algorithm to compute asymmetry from the 3 axial sensor data. We propose two applications of the system: for real time active correction and for data logging. In the correction mode, adjustment signal are sent to the user during the training by vibrations. The vibration signal is sent to the specific leg and its intensity is related to the entity of required correction. The second application of the system is as datalogger. The device stores all the training data in a SD card. Those log files can be processed using a dedicated application on a PC. This information can be very useful for long term analysis. This novel approach to sport training is very useful to athletes and sport medicine doctor in order to improve posture, efficiency and performance, but it can be also useful in other medical appliances such as rehabilitation. © 2011 IEEE.

Keywords: posture correction , sport training , vibro feedback , wearable

Materials simulation in virtual prototyping is one of the most challenging issues as not completely fulfilled by current devices. It allows Virtual Reality-based interfaces to provide multisensory interaction and to enhance product experience by mainly stimulating user emotional response. In this context the paper presents a new tactile simulation approach based on material surface properties elaboration and processing to stimulate roughness and texture coarseness perception. The developed approach leads to the development of a tactile display and a software tool to manage the configuration of selective stimulating signals. The main problem the research aims at overcoming, regards with the nature of signals adopted by most electrotactile displays and the way to stimulate skin mechanoreceptors. The paper focuses on the description of the adopted approach and of the implemented software tool in order to control the tactile display. Copyright © 2011 by ASME.

Keywords: HumanComputer Interaction , Material simulation , Multisensory interaction , Selective stimulation , Tactile display

This work concerns the usability assessment of two control devices for a wheelchair-mounted robot manipulator aimed at assisting physical disabled people. The assessment of the usability is a crucial issue for the design of such products, since they communicate with their users not only through their shape, but especially through their control interfaces. In a first phase, the study focuses on defining a synthetic usability index on the basis of the methodologies currently in use. In a second phase, some experiments in Virtual Reality (VR) have been carried out. The use of VR technologies for the collection of the experimental data has been fundamental in terms of safety, costs and repeatability of the tests. Another important result has been the reduction of the sources of noise, thanks to preliminary simulations in VR and non-invasive questionnaires and interviews for capturing the subjective perceptions of users. Finally, it is worth noticing that the developed model may show its validity also in evaluating the usability of other products. Indeed, it provides a basis for a more extensive use of VR experiments for evaluating different design solutions in terms of global usability requirements. © Organizing Committee of TMCE 2010 Symposium.

Keywords: Analytic Hierarchy Process (AHP) , Assistive robotics , Participatory design , Usability index , Virtual reality experiments

This paper presents a methodological approach to evaluate ergonomic issues of refrigerated display units. It is based on the use and integration of virtual human models with virtual prototyping techniques in order to support and optimize the product development process. The methodology has been investigated simulating the behaviour of two users' categories (customers and operators), which have different roles, needs, and ways of interaction with the machinery. Regarding customers, aspects related to reach capability and visibility were analyzed and quantified. For the operators, two typical tasks were analyzed (loading a unit and serving a customer), evaluating postures and movements respect to requirements established by international standards to reduce health risks. Ergonomic simulations were carried out varying unit type and configuration (number and types of shelves, etc.), manikin size and packed food (sizes and weight). © 2010 Taylor & Francis.

Keywords: Ergonomic analysis , Reaching , Refrigerated display units , Virtual human , Visibility

The development of safe and dependable robots for physical human-robot interaction is actually changing the way robot are designed introducing several new technological issues. Outstanding examples are the adoption of soft covers and compliant transmissions or the definition of motion control laws that allow a compliant behavior in reaction to possible collisions, while preserving accuracy and performance during the motion in the free space. In this scenario, a growing interest is devoted to the study of variable stiffness joints. With the aim of improving the compactness and the flexibility of existing mechanical solutions, a variable stiffness joint based on the use of compliant flexures is investigated. The proposed concept allows the implementation of a desired stiffness profile and range along with the selection of the maximum joint deflection. In particular, this paper reports a systematic procedure for the synthesis of a fully-compliant mechanism used as a non-linear transmission, together with a preliminary design of the overall joint. © 2010 by ASME.

This paper addresses issues related to the assessment of product designs that today successfully uses virtual prototyping methods and techniques. Design assessment is usually performed by engineers and designers. Current trend is involving customers in the products design assessment in order to check the level of acceptability and satisfaction before proceeding with the production. In this view, methods for design review may be used in participatory design sessions where customers can intervene for customizing products. The paper presents a tool that has been originally developed for designers for the validation and modification of aesthetic properties of digital shapes, and that has also been used by customers, in participatory design sessions, for customizing their products. Copyright © 2010 by ASME.

Some Virtual Reality applications are based on the use of haptic interfaces for a more intuitive and realistic manipulation of the virtual objects. Typically, the haptic devices have a xed position in the real space, and their working space is rather limited. As a consequence, there are locations in the virtual space that are out of the working space of the haptic device, and thus cannot be reached by users during the virtual objects manipulation. The paper describes a multimodal navigation modality based on the integrated use of various and low cost interaction devices that can be operated by a user taking into account that one of his hands is engaged for the manipulation of the haptic device. Therefore, we have decided to implement the user interface by using the Nintendo® Wii Remote™ and the BalanceBoard™, which can be operated by the user using the other hand and his feet. The navigation modality has been integrated and tested in a Virtual Reality application for the virtual manual assembly of mechanical components. A preliminary validation of the application has been performed by an expert user with the aim of identifying major usability and performance issues by using the heuristic evaluation method. © 2010 by ASME.

Mixed Reality (MR) technologies allow us to create different environments, by merging real and virtual objects, and can be successfully used for the assessment of industrial products during the product development phases. This paper describes the integration of a MR environment including an industrial robotic arm for the ergonomics assessment of the driving seat in the automotive field. The robotic arm has been used to configure the MR environment automatically while guaranteeing the correct merging between real and virtual objects and the repeatability of the testing sessions. The user's presence, near an industrial robot, arises some issues on the safety and on the human-robot interaction that we have been addressed in order to improve the performing of the ergonomic test. Finally, the developed system has been validated through some testing sessions with end users to verify the effectiveness of our solution. © 2010 IEEE.

One of the open issues in Augmented Reality (AR) applications is certainly related to interaction techniques. In these years many different solutions have been proposed with the intent of providing user interfaces that allow users to interact with the AR environment in a natural and intuitive way. Most of them have addressed the issue of representing users' hands in the AR environment. We propose the use of a commercial and low-cost wireless device to use as input device for AR. This paper describes the integration of this device into an AR application, and some preliminary tests aiming at evaluating the tracking accuracy and precision. In addition, we demonstrate the usability of our system through a preliminary testing session with users. ©2010 IEEE.

Keywords: Multimedia Information Systems, Artificial, augmented, and virtual realities, User Interfaces, Ergonomics, Input devices and strategies, Computer-Aided Engineering, CAD

Part modelling in a CAD environment requires a bi-manual 3D input interface to fully exploit its potentialities. In this research we provide extensive user tests on bi-manual modelling using different devices to control 3D model's rotation. Our results suggest that a simple trackball device is effective when the user task is mostly limited to rotation control (i.e. when modelling parts in a CAD environment). In our tests, performances are even better than those achieved with a specifically designed device. Since the task of rotating a CAD part often shows the need of flipping the controlled object, we introduce a non linear transfer function which combines the precision of a zero order control mode with the ability to recognise fast movements. This new modality shows a significant improvement in the user's performances and candidates itself for integration in next generation CAD interfaces. © 2008 Elsevier Ltd. All rights reserved.

Keywords: 3D input , Bimanual interaction , Human computer interface , Part modelling , VR CAD

During product development, usability tests allow the investigation of product performance in terms of effectiveness and user satisfaction. Virtual Reality (VR) systems provide new modes of Human-Computer Interaction (HCI) that can support usability testing at the early design stages by adopting virtual prototypes to simulate product experience. The problem is that only posture and occlusion parameters can be easily measured while the emotional and affective dimension is difficult to be assessed. In this context, the present paper focuses on two objectives. Firstly, it aims at investigating which product attributes stimulate affective user response by defining a structured protocol to analyze how sample users experience product attributes determining affordance and synaesthesia qualities. Then, real and virtual environments are compared in order to address VR systems improvements. Consequently, the second goal is to define a new VR-based environment for usability testing by considering a proper set of existing technologies integrated with a proposed multi-sensorial system for materials texture and roughness perception. Protocol experimentations are carried out in household appliances. © 2010 Taylor & Francis Group.

One of the most significant challenge of Virtual Reality (VR) in industry is to support the interaction with product models while enhancing the collaborative product development (CPD) by improving team working in the extended enterprise. The process success highly depends on how information flows and which representational means and supporting environments are adopted. This paper explores the impact of VR applications on collaboration focusing on co-design requirements, participants behavior and exploited interaction modalities. A benchmarking method is defined to select the proper co-design virtual environment for specific forms of collaboration carried out in different time-space domains. It adopts protocol analysis techniques to objectify both practical and cognitive human factors and it applies Quality Functional Deployment (QFD) matrices to correlate collaboration requirements and tools functionalities. Experimental tests have been carried out on synchronous and remote co-design activities, where VR tools have been poorly exploited. Achieved results highlight main limitations and strengths of the analysed technologies, addressing future developments in collaborative virtual environments. © 2010 by ASME.

The importance of Human-Centered Design (HCD) drives research toward the development of new UIs (User Interfaces) in order to predict human interaction with products at the early design stages. Virtual Reality (VR) allows carrying out usability tests on virtual prototypes to investigate users' cognitive and affective response. Application problems regard with the reproduction of synaesthesia qualities in order to make the information processing similar to the one obtained by real sensory stimulation. While visualization technologies seem to be mature enough to overcome the above mentioned limitation, tactile devices are still far from properly simulating materials properties. In this context, the present work aims at structuring and applying a systematic approach to conceive, define and develop a novel VR-based technology, called IperTouch. The goal is to stimulate the skin mechanoreceptors to generate a meaningful tactile sensation about materials softness, friction and roughness. The system can be also integrated with imaging and sound technologies to create a multi-sensorial product experience. The preliminary architecture results from the analysis of human tactile perception and the benchmark of available simulation devices and techniques. This paper contributes to discuss current issues of existing VR-based technologies in supporting HCD applications and to address technical developments toward the creation of a reliable system for texture perception. Keywords: Human-Centered Design (HCD), Human-Computer Interaction (HCI), virtual touch, material simulation, product experience. Copyright © 2010 by ASME.

Product designers, in order to create value, need to enrich their understanding of users products experience and the whole set of activities involved in it. Human-Centered Design (HCD) regards with the development of design principles to support product features definition answering to physical, psychological, social and cultural needs of human beings. Usability tests generally allow the investigation of product performance in terms of efficiency, effectiveness and users satisfaction in order to reduce the gap between the perceived and the designed product quality. Main problems concern with the assessment of emotional usability, the identification of product features stimulating affective response and their translation into design requirements. Usability tests are generally carried out only at the end of the design cycle once a final physical prototype has been realized. As a consequence design modifications increase time to market. Instead of traditional CAD-based systems (Computer Aided Design), Virtual Reality (VR) represents new Human-Computer Interfaces that can support the multimodal interaction with virtual prototypes to perform usability tests at the early design stages. The present paper explores the potentialities of VR to support usability testing mainly focusing on emotional aspects. A protocol study is defined to analyze how sample users perceive product attributes determining affordances and synaesthesia qualities. The protocol adopts qualitative and quantitative metrics to objectify users emotional response while interacting with products. It allows correlating product attributes, in terms of materials, shape and aesthetic features combination, with user behavior and product performance. It has been applied in the field of household appliances. Two different experimental set-ups, physical and virtual, have been used to validate the protocol and highlight the main VR technologies drawbacks. Copyright © 2009 by ASME.

Keywords: Human computer interaction (HCI) , Tactile virtuality , Usability , User emotional response , Virtual prototyping (VP)

The usability of the user interface is a key aspect for the success of several industrial products. This assumption has led to the introduction of numerous design methodologies addressed to evaluate the user-friendliness of industrial products. Most of these methodologies follow the participatory design approach to involve the user in the design process. Virtual Reality is a valid tool to support Participatory Design, because it facilitates the collaboration among designers and users. The present study aims to evaluate the feasibility and the efficacy of an innovative Participatory Design approach where Virtual Reality plays a 'double role': a tool to evaluate the usability of the virtual product interface, and a communication channel that allows users to be directly involved in the design process as co-designers. In order to achieve these goals, we conducted three experiments: the purpose of the first experiment is to determine the influence of the virtual interface on the usability evaluation by comparing "user-real product" interaction and "user-virtual product" interaction. Subsequently, we tested the effectiveness of our approach with two experiments involving users (directly or through their participation in a focus group) in the redesign of a product user interface. The experiments were conducted with two typologies of consumer appliances: a microwave oven and a washing machine. © 2009 Elsevier Ltd. All rights reserved.

Keywords: Participatory design , Product interface design , Usability , Virtual reality