Human factors and ergonomics

An algorithm for both human-like motion generation and joint torques computation for digital humans is addressed in this paper. This goal has been achieved using techniques derived from robotics. In particular, the so-called augmented Jacobian has been used to solve the inverse kinematics problem with a single closed loop inverse kinematics algorithm. Furthermore, a position control for the center of mass of the kinematic chain, and for its projection on the support plane (center of pressure), has been implemented to achieve easy posture control. Thus, the inverse kinematics can be solved taking into account the static balance of the digital human. Moreover, the proposed algorithm allows simulating quite complex tasks, which involve the motion of the whole body, by means of only few task-related control points arbitrary located on the whole kinematic chain. The resulting movements are quite natural even for complex tasks as can be seen on the simulation experiments reported which show the effectiveness of the proposed approach. Finally, the joint torques can be computed thanks to the kinetostatics duality: the results are in accordance with biomechanical analyses. © 2011 Springer-Verlag.

Keywords: Digital humans , Human-like motion generation , Kinetostatic duality , Low-back biomechanical analysis , Multiple-point kinematic control , Posture control

With the aim of reproducing the grasping and manipulation capabilities of humans, many robotic devices have been developed all over the world in more than 50 years of research, starting from very simple grippers, normally used in industrial activities, to very complex anthropomorphic robotic hands. Unfortunately, the reduced functionality and/or reliability of the devices developed so far prevent, together with the cost, their usability in unstructured environments, and in particular in human everyday activities. The adoption of design solutions inherited from conventional mechanics and the lack of purposely developed sensors and actuators are among the main causes of the partial fail in achieving the final goal of reproducing human manipulation capabilities. Our research activity aims at developing innovative solutions concerning the mechanical design, the sensory equipment and the actuation system for the implementation of anthropomorphic robotic hands with improved reliability, functionality and reduced complexity and cost, considering also aspects related to safety during human-robot interaction, paving the way toward the next generation of robotic hands. © 2012 Springer-Verlag GmbH Berlin Heidelberg.

Background: A fundamental pre-requisite for the clinical success in dental implant surgery is the fast and stable implant osseointegration. The press-fit phenomenon occurring at implant insertion induces biomechanical effects in the bone tissues, which ensure implant primary stability. In the field of dental surgery, the understanding of the key factors governing the osseointegration process still remains of utmost importance. A thorough analysis of the biomechanics of dental implantology requires a detailed knowledge of bone mechanical properties as well as an accurate definition of the jaw bone geometry.Methods: In this work, a CT image-based approach, combined with the Finite Element Method (FEM), has been used to investigate the effect of the drill size on the biomechanics of the dental implant technique. A very accurate model of the human mandible bone segment has been created by processing high resolution micro-CT image data. The press-fit phenomenon has been simulated by FE analyses for different common drill diameters (D A = 2.8 mm, D B = 3.3 mm, and D C = 3.8 mm) with depth L = 12 mm. A virtual implant model has been assumed with a cylindrical geometry having height L = 11 mm and diameter D = 4 mm.Results: The maximum stresses calculated for drill diameters D A, D B and D C have been 12.31 GPa, 7.74 GPa and 4.52 GPa, respectively. High strain values have been measured in the cortical area for the models of diameters D A and D B, while a uniform distribution has been observed for the model of diameter D C . The maximum logarithmic strains, calculated in nonlinear analyses, have been ε{lunate} = 2.46, 0.51 and 0.49 for the three models, respectively.Conclusions: This study introduces a very powerful, accurate and non-destructive methodology for investigating the effect of the drill size on the biomechanics of the dental implant technique.Further studies could aim at understanding how different drill shapes can determine the optimal press-fit condition with an equally distributed preload on both the cortical and trabecular structure around the implant. © 2012 Frisardi et al.; licensee BioMed Central Ltd.

The H.U.S.H. LIFE+ project (Harmonization of Urban noise reduction Strategies for Homogeneous action plans), approved by European Commission into the LIFE+2008 financial program, moves from the evidence that harmonization of noise action planning methods is needed in all the European countries where a former Legislation about noise planning was in force when Environmental Noise Directive (END) 49/2002/EC, [1], was adopted. The general aim is harmonizing national noise management standards with END for obtaining homogeneous noise Action Plans, in order to provide a contribution to the more general need of transposing, implementing and enforcing a common or harmonized environmental legislation among EU countries. Specific aims of the project are: to point out unsolved conflicts among current standards at Regional, National and European level; to define common methods for designing strategic and specific solutions; to define a new development system for action planning; to design guidelines for action plans implementation. In a previous publication, [2], the results of data collection were described and some critical issues were pointed out about noise mapping and action planning procedures. Based on this outcome, during the HUSH project, an harmonized methodology has been developed for noise mapping and action planning and it is presented in this work. © European Acoustics Association.

The importance of participatory design (PD) is progressively increasing thanks to its capacity to explore a wide variety of concepts, thus increasing the opportunity to create a successful product. In fact the design process should not be a solo activity, as designers often need inputs and other points of view, especially from end-users. According to the ultimate idea of PD, end-users are actively involved in the various activities of the product development to ensure that their needs and desires are satisfied. This paper presents a novel approach to the participatory design of product interfaces in a user-centered design (UCD) process. The approach is based on an interactive tool that allows end-users to design custom user interfaces of household appliances taking advantage of their own needs and experiences. The tool incorporates the analytical and more abstract knowledge of the designers codified in the form of aesthetical, technological and manufacturing constraints (i.e., limitations in the number and geometry of interface components, a limited number of colors, a discretization of the area where interface widgets are placed). This solution allows the end-users to directly design their favorite interface without the interference of any other subject. Through an accurate analysis of the choices done by the users, the designers are able to access to the deepest level of the usersâTM expression in order to catch their latent needs and tacit knowledge. The tool has been designed in order to make possible to immediately perform usability tests on the designed interface by using a Mixed Reality prototype. The paper describes the development of the tool and proposes a methodology that has been specifically addressed to include this tool in a design process based on UCD principles. Both the tool and the methodology are presented through the description of a case-study related to the redesign of a washing machine dashboard. Experimental results show that the proposed tool can be an effective support to design product interfaces during PD sessions. Copyright © 2012 by ASME.

Keywords: Participatory design , Usability , User-centered design

This chapter presents a methodology that the authors developed for the evaluation of a novel device based on haptic guidance to support people with disabilities in sketching, hatching, and cutting shapes. The user's hand movement is assisted by a sort of magnet or spring effect attracting the hand towards an ideal shape. The haptic guidance device has been used as an input system for tracking the sketching movements made by the user according to the visual feedback received from a physical template without haptic assistance. Then the device has been used as an output system that provides force feedback capabilities. The drawn shape can also be physically produced as a piece of polystyrene foam. The evaluation methodology is based on a sequence of tests, aimed at assessing the usability of the device and at meeting the real needs of the unskilled people. In fact, the system has been evaluated by a group of healthy and unskilled people, by comparing the analysis of the tracking results. The authors have used the results of the tests to define guidelines about the device and its applications, switching from the concept of "test the device on unskilled people" to the concept of "testing the device with unskilled people." © 2013, IGI Global.

In face-To-face communication, touch can establish intimacy, and therefore the presence of tactile stimulation can enhance the interpersonal relationships. While human-human interaction has been shifting from face-To-face physical conversations to electronically mediated form of communication, current technologies are not able to provide a multimodal sensorial experience that can support haptic interaction besides visual and auditory. Within the haptic research fields, affective haptics explore emotional interaction and perception mediated via touch that is simulated by technology. Besides, wearable technology and tangible interfaces can be employed as a solution to bridge the gap between the digital and physical worlds by making the body fully engaged with the interaction. This paper presents findings of a design practice that explores the avenues of affective tactile interaction through wearable technology, which can artificially produce tactile stimulations as medium for instant communication between two people. The findings are presented by the light of theoretical background, observations and analysis of the design practice. Copyright © 2012 by ASME.

Emotion is an intangible fact that is woven into interpersonal relationships in order to sustain social bonds with more understanding, trust and intimacy. Today, people are in an era of digitally mediated HHI (Human-to-Human Interaction), which is transforming the traditional way of communication and social dynamics. In order to increase the affective level of communication, research areas, such as affective haptics and wearable technology have emerged to find more affective interaction avenues and convey human emotions through technology in a more physical way. This paper presents a survey and a design practice that aim to explore how wearable technology can enhance emotional intimacy by introducing new ways for expressing emotions. The analysis of this study is addressed on the privacy issue of emotional expression through wearable technology and intimacy of emphatic communication through these agents.

Keywords: Design practice , Emotion , Interaction , Intimacy , Wearable technology

The selection and customization of usability evaluation methods, given the peculiarities of their application domains, still remains a critical issue; this especially when dealing with complex products and/or nonexpert usability evaluators. Moreover, as time goes by, the quality of the evaluation results has a heavier impact on the product design process. Starting from classic usability evaluation methods, the research described in this article generates multimethods semiautomatically. It allows quantitative characterization of these multimethods before their application in the field and exploits the comparison between this prior assessment and a final estimate, made after adoption, to update the information used by the method selection process. The most critical issue related to usability, subjectivity, is considered and dealt with throughout the entire research. A case study, done at the end of the development phase, helps validate the proposed approach to usability evaluation. © 2012 Taylor and Francis Group, LLC.

Highly usable human-system interfaces can have a large benefit on the quality of life for the elderly and disabled. New emerging product design technologies, such as Virtual Reality (VR) and Augmented Reality (AR), give many opportunities to evaluate and improve system usability in the early design stages. In this way different design alternatives can be evaluated in terms of physical and cognitive performance. In this context the present paper describes a systematic approach for designing highly usable home environments and optimizing human-machine interaction. VR/AR technologies are adopted for user interface evaluation. The approach will be applied to the design of a new kitchen.

Keywords: Augmented Reality , Home environment usability , Inclusive design , User interfaces , Virtual Reality

The research goal is material texture simulation by means of electro-tactile stimuli. This paper presents a novel tactile display, the procedure adopted to generate the stimulating signals, and the experimental testing. The tactile system elaborates data from scans of real material samples and generates electrical stimuli to reproduce roughness and texture coarseness sensations. It also adds a coherent sound feedback to improve the realism of the simulation. The research defines an experimental protocol to carry out system calibration and tests with users in order to validate the proposed tactile system as a new tool for material simulation. Experimentations have been carried out to measure the users' response to different material classes (wood, paper, rubber, textile fabric). Experimental results concern how good the adopted simulation approach is and the tactile stimuli simulated by the system are. Main findings relate to the system performance and the users' response in terms of signal recognition and material class discrimination. © 2012 IEEE.

Keywords: Advanced tactile display , Material simulation , Multimodal and multisensory interaction , Perception & Psychophysics

The paper presents a novel tactile display to simulate material properties such as roughness and texturewhile exploringVirtual Prototypes surfaces inVirtual Reality environments.The final aim of the system is to immerse users into an involving and enhanced product experience stimulating emotional and affective reaction. The developed display adopts a selective stimulation technique to differently activate skin mechanoreceptors and hence to generate surface texture sensations. The stimulation is realized by both an electric component made of a pin matrix through which the current flows and by a mechanical one obtained by a shaker keeping the tactile pad vibrating. Main development stages are described and experimental results discussed. They show that almost 65% of users are able to discriminate different signals. When acoustic cues are added, this percentage increases. © 2012 Taylor & Francis Group, London.

No abstract available

This paper presents a novel study on the simulation of material texture by means of electro-tactile stimuli and details the effects on the users' ability to recognize and discriminate different material classes. The research exploits a novel tactile display to simulate material texture and validates the adopted simulation strategy by experimental testing. The tactile system elaborates data from real material samples and combines electrical stimuli and mechanical vibration to reproduce both roughness and texture coarseness sensations. Then, an experimental protocol based on the theory of Psychophysics is defined to carry out system calibration and tests with users. The research aims at validating the proposed simulation strategy and checking the user response on virtual tactile stimuli. Experimentations were carried out to reproduce virtual material texture and measure the users' ability to distinguish different virtual materials and to recognize the material class. Experimental results provide interesting details about tactile perception mechanisms and validate the adopted approach for tactile signals' recognition and material class discrimination. Copyright © 2012 by ASME.

The search for safe vehicles is increasing with both diffusion of high traffic density over the world and availability of new technologies providing sophisticated tools previously impossible to realize. Design and development of the necessary devices may be based on simulation tests that reduce cost allowing trials in many directions. A proper choice of the arrangement of the drive simulators, as much as of the parameters to be monitored, is of basic importance as they can address the design of devices somehow responsible for the drivers safety or, even their lives. This system setup, consisting of a free car simulator equipped with a monitoring system, collects in a nonintrusive way data of the car lateral position within the road lane and of its first derivative. Based on these measured parameters, the system is able to detect symptoms of drowsiness and sleepiness. The analysis is realized by a fuzzy inferential process that provides an immediate warning signal as soon as drowsiness is detected with a high level of certainty. Enhancement of reliability and minimisation of the false alarm rate are obtained by operating continuous comparison between learned driver typical modalities of operation on the control command of the vehicle the pattern recorded. © 2012 Pasquale Sena et al.

Variable stiffness actuators can be used in order to achieve a suitable trade-off between performance and safety in robotic devices for physical human-robot interaction. With the aim of improving the compactness and the flexibility of existing mechanical solutions, a variable stiffness actuator based on the use of flexures is investigated. The proposed concept allows the implementation of a desired stiffness profile and range. In particular, this paper reports a procedure for the synthesis of a fully compliant mechanism used as a nonlinear transmission element, together with its experimental characterization. Finally, a preliminary prototype of the overall joint is depicted. © 2011 American Society of Mechanical Engineers.

Interacting with computers by using the bodily motion is one of the challenging topics in the Virtual Reality field, especially as regards the interaction with large scale virtual environments. This paper presents a device for interacting with a Virtual Reality environment that is based on the detection of the muscular activity and movements of the user by the fusion of two different signals. The idea is that through muscular activities a user is capable of moving a cursor in the virtual space, and making some actions through gestures. The device is based on an accelerometer and on electromyography, a technique that derives from the medical field and that is able to recognize the electrical activity produced by skeletal muscles during their contraction. The device consists of cheap and easy to replicate components: seven electrodes pads and a small and wearable board for the acquisition of the sEMG signals from the user's forearm, a 3 DOF accelerometer that is positioned on the user's wrist (used for moving the cursor in the space) and a glove worn on the forearm in which these components are inserted. The device can be easily used without tedious settings and training. In order to test the functionality, performances and usability issues of the device we have implemented an application that has been tested by a group of users. Specifically, the device has been used as natural interaction technique in an application for drawing in a large scale virtual environment. The muscular activity is acquired by the device and used by the application for controlling the dimension and color of the brush. Copyright © 2011 by ASME.

The paper describes a collaborative Mixed-Reality (MR) environment to support the product design assessment. In particular, we have developed a collaborative platform that enables us to improve the design and the evaluation of cars interior. The platform consists of two different systems: the 3D Haptic Modeler (3DHM) and the Mixed Reality Seating Buck (MRSB). The 3DHM is a workbench that allows us to modify the 3D model of a car dashboard by using a haptic device, while the MRSB is a configurable structure that enables us to simulate different driving seats. The two systems allow the collaboration among designers, engineers and end users in order to get, as final result, a concept design of the product that satisfies both design constraints and end users' preferences. The usability of our collaborative MR environment has been evaluated by means of some testing sessions, based on two different case studies, with the involvement of users. Copyright © 2011 by ASME.