Human factors and ergonomics

In the field of Ambient Assisted Living, the present research proposes a combined User-Centred Design approach that exploits the strengths of systematic and participatory design methodologies with the final aim to design an assistive device to solve mobility problems of elderly people in crowded environments. The application of the approach allows research to investigate which information gathering technique is more effective for this context of use and to find out competitive AAL solutions for specific target users. The experimentation is carried out by students attending an industrial design course. An experimental protocol is arranged to compare the outcomes from the different stages of the approach application. The scientific contribution of the present work regards both the presented results, that confirm how much effective is ethnography in respect to role-playing and traditional desk research in case of products oriented to special target users, and the educational experiences in the field of AAL.

Keywords: Ambient assisted living , Design education , Evaluation , Requirement gathering , User centred design

Accessibility to graphical user interfaces by visually impaired persons is generally enabled through systems, which reproduce the lexical structure of the user interface to a nonvisual form, mainly employing 3D audio output techniques. Two main critical issues have been identified: (i) most interfaces address the needs and abilities of sighted users and consequently the reproduction is only a translation from one language to another; (ii) blind users are generally not involved in the development stage due to the cost of prototyping. The present work proposes an interactive user interface to control a multi-sensory shower accessible by both sighted and blind users and able to adapt its control knob to reproduce Braille texts. Such function is realized by the integration of an electrotactile feedback device and adopts soft touch finishing to better stimulate touch sensations. Haptic technologies have been exploited to create a virtual high-fidelity prototype to assess individual end-users' response during the user interface design process. The paper illustrates the designed interface to assist blind users in home environments and the adopted virtual prototyping technique to address the above-mentioned issues.

General comfort can be defined as the measure of the "level of wellbeing" perceived by humans when interacting with a working environment. The state of the art for comfort/discomfort evaluation shows the need for an objective method to evaluate both "effects on the internal body" and "perceived effects" when considering the perception of comfort. Medical studies show that each joint has its own natural resting posture. In this posture, our muscles are completely relaxed or at minimum levels of strain. The body's geometrical configuration corresponds to the natural resting position of arms/legs/neck etc. From this starting point, the authors experimented to develop and built postural-comfort curves for each degree of freedom (DOF) of upper-limb joints. These curves are regular, and do not show any kind of discontinuity. Software (CA-Man®) was developed to analyze different postures and calculate a postural comfort index for the entire upper body. This paper examines a postural comfort study that has been used to develop the MATLAB® Digital Human Model. Several routines for tracing trajectories while reaching for commands in a confined environment (e.g., a work table or a car-cockpit) were evaluated to obtain the maximum perceived postural comfort for each target point. Iso-comfort points were defined for each space, and iso-comfort surfaces were designed using an appropriate CAD system. An example of these routines is shown below. Iso-comfort surfaces can be also customized for different percentiles. This allows car-interior designers to have a virtual knowledge of the final perceived comfort when they decide, for example, on the positioning of a dashboard command.

The aim of this paper is to investigate an iterative statistical procedure, based on a small and censored sample of impact test experiments, useful for interval estimation of head impact safety parameter as critical fall height of protective devices. An adaptive testing routine was developed that was mainly constituted by a series of at least four impact test experiments, followed by the comparison of at least two parameter estimates based on incremental exponential regression fittings and a final confirmation experiment. A total number of 23 protective devices, mainly made of polyethylene foam, were investigated in order to validate the adaptive routine. The routine, applied to critical fall height of protective devices, was 19 times convergent within a maximum of 6 impact test experiments. 4 times the sample was censored because the iterative procedure has exceeded the available number of specimens. Confidence intervals at the 90 % level were always less than 0.18 m. The applicability of the adaptive routine was satisfactory demonstrated with reference to devices made of PE-foam and safety threshold of peak acceleration a-max equal to 200 g. The target of a confidence interval below the state-of-art was achieved. © 2014 Elsevier Ltd.

Keywords: ASTM F 1292 , Critical fall height , Impact attenuation , Sports safety

Motion capture of the human body has being performed for decades with a growing number of technologies, aims and application fields; but only recent optical markerless technologies based on silhouette recognition and depth sensors which have been developed for videogames control interface have brought motion capture to a broad diffusion. Actually, nowadays there are low cost hardware and software suitable for a wide range of applications that may vary from entertainment domain (e.g., videogames, virtual characters in movies) to the biomechanical and biomedical domain (e.g., gait analysis or orthopedic rehabilitation) and to a huge number of industrial sectors. In this quick evolving scenario it is hard to tell which technology is the most suitable for any desired goal. The aim of the paper is to answer to this issue by presenting a benchmark analysis that compares RGB and RGB-D technologies used to track performing people in a variety of conditions. In order to contrast the solutions, several different tasks have been selected, simultaneously captured and post-processed exactly in the same way. The test campaign has been designed to evaluate pros and cons according to the most important feature of a motion capture technology, such as volume of acquisition, accuracy of joint position and tracking of fast movements. Actors were asked to perform a number of tasks, among which free movements of arms, legs and full body, gait, and tasks performed interacting with a machine. The number of sensors around the scene and their disposition have been considered as well. We used Sony PS Eye cameras and Microsoft Kinect sensors as hardware solutions and iPisoft for data elaboration. The gathered results are organized, compared and discussed stressing performances and limitations of any combination and, at last, we proposed the best candidate technology for some key applications.

Keywords: Benchmark , Depth cameras , Digital Human Models , Motion capture , RGB , RGB-D

This paper refers to the design of prosthetic socket adopting a computer-aided approach. The main goal is to make available a modeling tool, named SMA-Socket Modeling Assistant, which permits to replicate/emulate manual operations usually performed by the prosthetist. Typically, s/he also relies on the sense of touch; therefore the underlying idea has been to develop and experiment haptic devices. The paper presents a haptic mouse at low-cost to make it affordable also by small orthopedic labs. It is essentially a traditional mouse device enhanced with a servomotor and a pressure sensor pad integrated with Arduino board and SMA. The application within SMA is described as well as the haptic interaction with physically-based model of the residual limb. Finally preliminary tests are illustrated. © 2014 Springer International Publishing Switzerland.

Keywords: Arduino , haptic devices , low cost haptic mouse , prosthesis socket modelling

This paper presents a research work on the augmented interaction applied to an innovative platform to design lower limb prosthesis, in particular the prosthetic socket. The underlining idea is to experiment low-cost hand-tracking devices, to manipulate the 3D virtual model of the socket using hands as traditional done by the prosthetist. The goal is to make available a modeling tool, named Socket Modeling Assistant-SMA that permits to replicate/emulate manual operations usually performed by the prosthetist during the traditional development process. Two devices have been considered and compared: the Leap Motion device and the Intel Gestures Camera. To this end a set of gestures has been identified to make more natural the interaction with SMA. Preliminary tests and results reached so are described and discussed.

This paper refers to the integration of simulations tools to assess the design of prosthetic devices. We address issues arising when the prosthesis needs to be virtually tested, i.e., the gait of the virtual patient wearing the prosthesis. Therefore, we integrate two different simulation tools: the first one to study the interaction between socket and residual limb during the gait and the second one to analyze the patient's gait deviations. Combining these numerical analyses, it is possible to investigate the causes of gait deviations and suggest remedies, both related to the prosthesis setup and the socket modeling. To prove the validity of the approach, we implemented a Finite Element Analysis model to analysis the stump-socket contact and we assembled a low cost Motion Capture system to acquire and elaborate patient gait. Preliminary results and remarks conclude the paper.

The contact pressure at the socket-residual limb interface is the most important parameter to evaluate comfort of leg prosthesis. Experimental works analyzed this parameter for typical postures and during walking of an amputee; but experimental tests require a real prototype of the socket equipped with transducers. To optimize socket design, this work presents a virtual approach based on a digital avatar of the patient wearing lower limb prosthesis. Our approach considers the integration of two different types of simulation: the first one concerns the multi-body gait analysis, the second one the pressure evaluation at the socket-residual limb interface with FE analyses. The paper describes the model used, the simulation tools adopted and their integration. Finally the case study related to patient walking on flat floor is described. © 2014 CAD Solutions, LLC.

Keywords: gait simulation , human modeling , prosthesis design , socket-residual limb contact

Current practices about selection, assessment and management of Quiet Areas in EU Countries, though regulated by the EU Directive 49/2002/EC on Environmental Noise, appear to be extremely fragmented and inhomogeneous. In fact, each country during past years adopted a set of strategies strictly related to specific contexts. Proposing a solution to overcome the lack of harmonized methodologies for Quiet Areas is the main aim of QUADMAP (QUiet Areas Definition and Management in Action Plans) project. The project has a high level of demonstrativeness guaranteed by the fact that the methodology proposed for identification, delimitation and prioritization of QUAs will be tested on a number of case study areas. In particular, it will be applied in a set of pilot cases in Italy, Spain, and in The Netherlands. The project started on 1st September 2011 and lasts three years. At the beginning of 2013 the harmonized methodology has been defined. The proposed procedure has been tested since February 2013 in all pilot cases and optimized according to data collected in the pilot cases. In this paper the optimization procedures are described, with particular attention to those developed in the period April-June 2014.

Current practices about selection, assessment and management of Quiet Areas in EU Countries, though regulated by the EU Directive 49/2002/EC on Environmental Noise, appear to be extremely fragmented and inhomogeneous. In fact, each country during past years adopted a set of strategies strictly related to their specific contexts. Proposing a solution to overcome the lack of harmonized methodologies for Quiet Areas is the main aim of QUADMAP (QUiet Areas Definition and Management in Action Plans) project. The results of the project will facilitate urban planners to apply standard procedures for identification, delimitation and prioritization of Quiet Urban Areas. The project has a high level of demonstrativeness guaranteed by the fact that proposed methodology will be tested on a number of case study areas. In particular, it will be tested in a set of pilot cases in Italy, Spain, and in The Netherlands. The project started on 1st September 2011 and lasts three years. At the end of 2012 the harmonized methodology has been defined. The proposed procedures have been tested since February 2013 in all pilot cases and, recently, the methodology has been optimized, in line with experiences gained during data collection within the pilot cases and analysis of the ante-operam scenarios. In this paper the optimization procedures are described with regards to these experiences gained in the pilot cases.

The Visuo-Haptic Mixed Reality (VHMR) is a branch of the Mixed Reality (MR) that is acquiring more and more interest in the recent years. Its success is due to the ability of merging visual and tactile perceptions of both virtual and real objects with a collocated approach. Like any emerging technology, the development of the VHMR systems is accompanied by challenges that, in this case, deals with the efforts to enhance the multi-modal human perception with the user-computer interface and interaction devices at the moment available. This paper deals with two of the typical problems related to VHMR systems, that are device obtrusion and tool-hand misalignment, and suggests solutions whose effectiveness has been tested by means of user studies. First, the paper analyzes the obtrusion problem and the benefits that users may gain performing task in a mixed environment with unobstructed haptic feedback, performed by means of a novel technique. Secondly, it investigates the effects of tool-hand misalignment on user perception and verifies the efficacy of a proposed misalignment correction technique by means of a comparative user test. Experimental results show that users would benefit from using the proposed unobstructed visuo-haptic approach and the misalignment compensation technique. These enhancements demonstrate the efficacy of the proposed solutions and at the same time get stronger the awareness that obtrusion and misalignment problems are fundamental issues to take into account for producing a realistic perception of a visuo-haptic mixed environment. © 2014 Elsevier Ltd.

Keywords: Haptic interaction , Occlusion handling , User evaluation , Visuo-Haptic Mixed Reality

Traffic calming devices on urban streets, such as elevated pedestrian crossings, speed bumps and roundabouts, are increasingly used, raising a real problem in relation to the on-board comfort that passengers perceive. To measure vibrational comfort related to traffic calming devices that passengers of the public transport perceive, an acquisition system called ASGCM (Autonomous System for Geo-referenced Comfort Measurements) has been developed, taking as a reference the European regulations on rail transports. ASGCM permits to link each measurement of vibration, ground velocity and acceleration with geographical information resulting from a GPS. In this way a map of a comfort index, statistical surveys and correlation between on-board comfort and traffic calming, can be directly obtained by any Geographic Information System (GIS), able to query a centralized remote database, which was developed ad-hoc. A large number of experimental tests has been performed to define a vibrational comfort index and to collect a large dataset that allows statistically significant comparisons between different infrastructures and their characterization. The proposed technique can also be useful for diagnostics purposes, such as vehicle comparison and road maintenance state monitoring.

Keywords: Geo-referenced comfort measurement , Thematic maps , Vibrational on-board comfort

The paper describes the design and preliminary virtual testing of OSHap, an open-source low cost 2DOF haptic interface. The aim the research is to create a mechatronic platform for haptic interaction based mainly on cheap and open source components. The results will be distributed freely in order to provide guidelines for expert users to develop their own haptic interface. Both the mechanical design philosophy and the control electronics are hereby discussed together with a preliminary testing made by using virtual prototyping tools. The kinematic layout is based on a serial double joint scheme. This choice is claimed to be the less expensive one, inasmuch as tolerances do not have to be narrow as for the parallel systems. The system also allows future users to tune dimensions (and relative workspace) easily. The interface is admittance controlled for maximizing the transparency with low cost drives. The device is based on the Intel Galileo open-source development board: this board embeds a powerful chip-sets that enables us to perform real-time 2DOF control tasks that are hardly reachable with the most common open source electronic platforms. All the choices listed above are discussed and evaluated, with focus on performance-to-cost ratio.

Understanding users points of view is rapidly becoming an urgent issue for companies and designers, as well as User Experience and Experience Design proving to be of wide interest for academic research. This paper presents an experimental-based methodology aimed at guiding designers during product optimisation. It is meant to support designers in choosing the right strategy to assess the users emotional reaction towards a product at an early stage of product development. The methodology consists of three different phases: 1) Design Challenge definition, to help in clarifying the research question; 2) Interaction Study, aimed at understanding the user experience; 3) Sensory Boost phase, to improve the products perceived pleasurableness. The methodology includes a review of the methods and tools used for catching users emotional reactions to products. Moreover, a computer-based version of the methodology will be introduced, together with two case studies to validate the developed methodology.

Keywords: Emotional design , Methodology , Sensory boost , User experience

The paper describes the issues related to the implementation and the control of a low cost 1DOF haptic device. Arduino, which has been widely adopted in the interaction design schools as a means to produce low cost, low-fi and rapid prototypes of interactive systems, has been used here as an alternative to more performing electronic control boards to control a DC motor and simulate a haptic knob. The idea is to explore the possibility of creating simple prototypes of haptic devices before building the final product. At this stage we have explored the implementation of a simple haptic knob, trying to identify the main issues. In particular, some control strategies have been used for the motor, and pros and cons are described in the paper. © 2014 IEEE.

Keywords: H.5.2 [Information Interfaces and Presentation]: User Interfaces?Haptic I/O

This study evaluated newly proposed Human-Machine Interface (HMI) design concepts for improving the ergonomics of hydraulic excavators. The design concepts were based on an augmented interaction technique which involved the use of heads-up display (HUD) and coordinated control as HMI elements. Two alternative HMI designs were elaborated in order to separately evaluate the ergonomic impacts of the head-up display and the coordinated control by comparing them to the standard HMI design. The effectiveness of these three HMI designs in terms of the reduction of the operators' mental and physical workload were assessed by conducting experiments utilizing human subjects, ages 23-35 years. The National Aeronautics and Space Administration's Task Load Index (NASA TLX) method was used for collecting subjective workload scores based on a weighted average of ratings of six factors: Mental Demand, Physical Demand, Temporal Demand, Own Performance, Effort, and Frustration Level. The results showed that the type of HMI design affects different aspects of the operator's workload. Indeed, it showed how the proposed augmented interaction is an effective solution for reducing the ergonomic gaps in terms of mental workload, and to a lesser extent the physical workload, subjected by the standard HMI design. Relevance to industry: This study proposes innovative HMI solutions featuring heads-up display and coordinated control to improve the ergonomics of the hydraulic excavator HMI, particularly in reducing the operators' mental and physical workload. The results of this study promises to be an innovative approach for developing new HMI designs by hydraulic excavator manufacturers. © 2014 Elsevier B.V.

Keywords: Coordinated control , Ergonomics , Heads-up display , Human-Machine Interface , Hydraulic excavator , NASA TLX

In this paper we introduce and describe a new concept in human-measurements operation that seems to be very useful for comfort evaluation: the Range of Rest Posture (RRP). Our study is focused on the identification of RRP -inside the comfort range of motion (CROM)-for the following human joints: neck, shoulder, elbow, wrist and ankle. Method used is based on a wide experimental work on 85 healthy individuals (43 males and 42 females) ranging in age from 20 to 30 year. The main target of this work is the experimental definition of CROM and identification of RRP; Experimental data has been processed by statistical methods for identifying the best statistical distribution in order to fit experimental data. Main result is the identification of RRP in CROM of main human joints involved in upper and lower limbs movements. In RRP weve found several maximum level of comfort positions in human postures: those position seems to be one of the most important information in comfort evaluation analysis. The state of the art about comfort/discomfort evaluation shows the need of an objective method to evaluate effect in the internal body and perceived effects in Moes (Contemporary ergonomics. Taylor & Francis, London, 2005) and Vink and Hallback (Appl Ergon 43:271-276, 2012) scheme of comfort perception; postural comfort is one of the aspect of comfort/discomfort perception and this paper helps to put a piece in the puzzle of posture evaluation. On the basis of papers results, a comfort evaluation method can be developed using RRP, CROM and building a composition rule that takes into account also lumbar comfort and H-point. Our work does not use ROM and CROM values coming from literature because each of these values has been experimentally identified. © 2013 Springer-Verlag France.

Keywords: Comfort evaluation , Human joints , Range of motion , Rest Posture

General comfort may be defined as the "level of well-being" perceived by humans in a working environment. The state-of-the-art about evaluation of comfort/discomfort shows the need for an objective method to evaluate the "effect in the internal body" and "perceived effects" in main systems of comfort perception. In the early phases of automotive design, the seating and dashboard command can be virtually prototyped, and, using Digital Human Modeling (DHM) software, several kinds of interactions can me modeled to evaluate the ergonomics and comfort of designed solutions. Several studies demonstrated that DHM approaches are favorable in virtual reachability and usability tests as well as in macro-ergonomics evaluations, but they appear insufficient in terms of evaluating comfort. Comfort level is extremely difficult to detect and measure; in fact, it is affected by individual perceptions and always depends on the biomechanical, physiological, and psychological state of the tester during task execution. These parameters cannot be modeled using software and instead have to be tested on physical models. A seating buck is often used to prototype a driver's seat, and virtual, mixed, and augmented reality devices help designers to improve ergonomics and comfort of a human-machine interface (HMI). In such environments, both postural and cognitive comfort can be evaluated, but often, testers' opinions are affected by devices, their interaction with designers, and especially, posture analysis systems. One solution to this kind of perception alteration can be found in non-invasive acquisition methods, such as acoustic, magnetic, or optical methods. Each has its own advantages and disadvantages, but all share the same characteristics: they are expensive and difficult to calibrate and use. This paper presents a new method for objectifying and evaluating postural and cognitive comfort levels based on human posture analysis and a questionnaire to evaluate cognitive performance. The posture acquisition method employs commercial low-cost cameras on tripods. The comfort evaluation methods, previously developed at the University of Salerno, are based on several experimental test campaigns, statistical processing, and biomedical studies. The method was tested in terms of reachability and usability for automotive drivers and was performed in a B-segment car (FIAT Grande Punto). A sensitivity analysis was performed to correlate the low resolution of the photographic acquisition with the consequent errors in the comfort evaluation. Posture acquisition errors were analyzed using DHM (DELMIA) software. Copyright © 2014 SAE International.

The traditional automotive design process that starts from the sketches and the 2D drawings has been superseded by the modern CAD modeling tools. The step through the clay model and the following digitalization problems can be superseded. It is now possible to construct the inside and to define the ergonomic boundaries of the vehicle in an inside out process. This approach greatly reduces the time to market of the final product by including all the parts and the components that comes from other projects or from outsourcing. However a 1:1 (true scale) physical mock up of the vehicle is, in most the cases, still necessary. In fact the evaluation of the real aesthetics of the new project should be made in a true 3D environment. The inside-out approach optimizes the standardization, the outsourcing, the multi powertrains and the unified "platform" concepts. © 2006-2014 Asian Research Publishing Network (ARPN).

Keywords: Automotive design , Methodology to design , Optimization