Human factors and ergonomics

Sitting still for extended periods of time can lead to physical discomfort and even serious health risks. Due to safety regulations, reducing passenger' sitting time in aircrafts is not feasible. This paper presents the results of a laboratory study, in where an interactive airplane seat was compared with a current economy class seat. Participants used both seats for 3.5 h, and performed significantly more in-seat movements when using the interactive seating system. Furthermore, this interactive seat predominantly lead to significantly better comfort experiences and reduced discomfort experiences, however no significant differences have been found in self-reported localized musculoskeletal discomfort. Passengers indicated that they would prefer this interactive seat over a standard aircraft seat.

Keywords: Aircraft interior , Airplane seat , In-seat exercise , Passenger comfort

Much research has been carried out in recent years to estimate perceived comfort levels for passengers in motor vehicles. This interest is in part due to the introduction of specific provisions (e.g. Law 81/08 in Italy). Another factor is the increased interest and attention of customers. These studies have concentrated in large part on driver position. However, this work describes an application of postural analysis of with results obtained via data acquired during the interaction between the passenger and the dashboard. Tests were carried out in the Virtual Reality Laboratory (VR Lab) at the University of Salerno using a physical mock-up of a passenger car seat involving a fully reconfigurable seating buck. The interior of a FIAT Grande Punto, MY 2013, was configured by setting the seating-buck parameters. Twenty participants were asked to sit in the car seat with their shoulders against the seatback. They were then asked to reach each of the dashboard buttons. To acquire the angles of the subject's joints, pictures were taken and processed using KINOVEA® software. Each subject was subsequently given a questionnaire to analyze subjective comfort perception for their neck, back, shoulders, arms, upper-arms and wrists. A virtual model of the front seat of a Fiat Grande Punto was developed in CATIA software environment, and each action involved in reaching a position and using a command was simulated using DELMIA® software. The anthropometric data for each subject was used to perform the virtual analyses. Reachability and visibility analyses - important factors in comfort perception - were carried out. CaMAN® software was used for the virtual assessment of upper-limb postural comfort. Statistical analyses were performed using SPSS® software to investigate potential correlations between:anthropometric data and comfort perceptions resulting from the questionnaires;anthropometric data and comfort indexes obtained by CaMAN® software;comfort indexes obtained by CaMAN® and from the questionnaires. The analyses showed a lack of strong correlations between anthropometric and comfort indexes calculated both by the questionnaires and by CaMAN®. Further analyses allowed us to understand the reasons for the weak correlation between the CaMAN and questionnaire results. Reachability was shown to strongly affect global comfort perception due to the perception of postural comfort. To understand the influence of reachability on global comfort perception, a new comfort perception function was developed, leading to some very interesting results.

The preventive evaluation of perceived (dis)comfort during the early stages of the design process is still an open issue. In Car development process, all tasks that involve human operations have to be taken into account while thinking and developing new solutions. Fortunately, modern technologies like CAE (Computer Aided Engineering) and DHM (Digital Human Modeling), and some new simulation software, like AnyBody™ or Jack© by Siemens PLM, allow to investigate, through simulation, some of the aspects related to comfort perception in humans. In addition, the software named CaMAN®, developed at University of Salerno, allows the postural comfort evaluations of upper limbs. The questions to which this paper tries to give answers are: (1) Is it possible to correlate the simulated muscular activation with perceived (dis)comfort during a manual task? (2) How different are the subjective perceived (dis)comfort, rated by the Borg Scale and the (dis)comfort index calculated by software?.

Keywords: (Dis)comfort perception , Car-Subsystems development , Comfort driven design , Human factors , Muscular fatigue evaluation , Task analysis

The analysis of workers' ergonomics and human factors is assuming a great importance in product and process design for modern industry. However, there is a lack of common references and structured protocols for the assessment of workers' experience in industrial practices in an effective and predictive way. As a result, designers are poorly supported in the application of digital technologies, which are demonstrating to have a great potential. This ascertainment suggested defining a reference model to analyse the so-called user experience (UX) of workers and a proper technological set-up based on virtual simulations in order to support human-centred product-process design. Indeed, the recent advances in ubiquitous computing, wearable technologies and low-cost connected devices offer a huge amount of new tools for human data monitoring. However, the open issue is selecting the most proper devices for industrial application area in respect with design goals, using virtual simulation and digital manufacturing tools. The research proposed a structured procedure to use existing digital technologies to support product-process design to analyse the workers behaviours and assess the perceived experience for industrial scopes. The paper defined a structured protocol analysis to objectify and measure the workers' experience with the final aim to support the requirements definition in product-process design by using digital technologies. In particular, the model has been defined for the automotive sector. The paper contribution is the definition of the protocol analysis and the development of a mixed reality (MR) set-up to involve real users' and to improve the digital models. Such a protocol has been applied to different industrial cases related to product and process design, developed in collaboration with CNH Industrial. The comparison with traditional design procedures highlighted the benefits of adopting virtual mock-up and digital simulation within a MR environment to shorten design time and improve the design overall quality.

Human factors are fundamental for manufacturing sustainability, which is determined by social, economic and environmental performance. However, there is a lack of engineering methods and tools that are able to integrate their analysis with product and process optimisation according to sustainability principles. The present study proposes an analytical approach to support sustainable manufacturing (SM) by analysing the so-called user experience (UX) of manufacturing and assembly processes starting from the early design stages. Considering both behavioural and cognitive aspects of manufacturing UX and defining a corresponding model, it is possible to estimate the UX impact on manufacturing sustainability for a certain product and its related processes. The proposed method is implemented in a computer-based framework, which can be easily integrated with environmental and cost assessment tools to integrate all three SM aspects. Finally, a case study focused on automated machines is presented; the proposed approach was used to redesign the machine to improve its economic, environmental and human-related impacts. The industrial case study provides concrete evidence of the achievable benefits of applying the proposed model in manufacturing practice. Indeed, the case study demonstrated how the manufacturing and assembly process of a specific machine was optimised by simplifying the product structure, changing the adopted materials and creating more human-centred activities. The new solution is more sustainable due to time savings (−30%), cost reduction (−20%), reduced environmental impact (−25%) and improved UX (+30%).

Keywords: computer-integrated approach , design for manufacturing & assembly (DFMA) , human factors , sustainability , user experience

Design for serviceability begins with understanding the customer needs related to availability, reliability, accessibility and visibility, and aims at designing optimized systems where maintenance operations are easy and intuitive in order to reduce the time to repair and service costs. However, service actions are difficult to predict in front of a traditional CAD model. In this context, digital manufacturing tools and virtual simulation technologies can be validly used to create mixed digital environments where service tasks can be simulated in advance to support product design and improve maintenance actions. Furthermore, the use of human monitoring sensors can be used to detect the stressful conditions and to optimize the human tasks. The paper proposes a mixed reality (MR) set-up where operators are digitalized and monitored to analyse both physical and cognitive ergonomics. It is useful to predict design criticalities and improve the global system design. An industrial case study has been developed in collaboration with CNH Industrial to demonstrate how the proposed set-up is used for design for serviceability, on the basis of experimental evidence.

Keywords: Design for serviceability , Digital Manufacturing (DM) , Ergonomics , Human-Centred Design (HCD) , Sustainability , Virtual Simulation

Human-centred design is based on the satisfaction of the user needs related to performances, aesthetics, reliability, usability, accessibility and visibility issues, costs, and many other aspects. The combination of all these aspects has been called as “perceived quality”, that is definitely a transdisciplinary topic. However, the “real” perceived quality is usually faithfully assessed only at the end of the design process, while it is very difficult to predict on 3D CAD model. In this context, digital manufacturing tools and virtual simulation technologies can be validly used according to a transdisciplinary approach to create interactive digital mock-ups where the human-system interaction can be simulated and the perceived quality assessed in advance. The paper proposes a mixed reality (MR) set-up where systems and humans interacting with them are digitalized and monitored to easily evaluate the human-machine interaction. It is useful to predict the design criticalities and to improve the global system design. An industrial case study has been developed in collaboration with CNH Industrial to demonstrate how the proposed set-up can be validly used to support human-centred design.

Keywords: Digital manufacturing , Human-centred design , Human-machine interaction , Virtual simulation

Driving is a high-demanding task, related to human capacity, required performance and events occurring in the external environment. In this context, the driver's health status monitoring is expected to support safety system and reduce the number of traffic accidents. Among the drivers' conditions, drowsiness and distraction are thought as crucial risk factors that may result in severe injuries. The paper defines a transdisciplinary roadmap to monitor the driver's health status and to map the perceived user experience, based on three layers: the human conditions to detect, the vital parameters to be monitored, and the adopted technologies. The paper proposes a technological set-up focusing on the driver's drowsiness detection, in the context of smart city framework and innovation 4.0. Indeed, such technologies could be embedded in the future “smart car” and communicate with external services to control the driver's performance and improve the safety inside and outside the car. A preliminary technological set-up has been realized embedded into a Maserati car.

Keywords: Digital identity , Human factors , Human-centred design , Innovation 4.0 , User experience

This study aims to develop an innovative approach based on a wearable inertial system, which enables objective evaluations on the of loss of ground contact in race-walking, in order to assist coaching and judging. The architecture of the system, its positioning on the human body and functional requirements were defined through a Kansei Engineering approach by using a significant sample of athletes, coaches and judges within the race-walking environment. The analysis of variance supports decisions concerning the optimal system architecture consisting of an inertial sensor positioned on the centre-of-mass of the subject and a control unit. The selected device was then validated in laboratory conditions by means of an integrated system, including dynamic (680 Hz) and kinematic (340 Hz) devices, which are more accurate than the inertial system (200 Hz). The experiment was carried out at the Fraunhofer JL IDEAS-MISEF at CESMA, Laboratory of Advanced Measures on Ergonomics and Shapes of the University of Naples Federico II where four elite race walkers performed 60 test-runs according to a well-defined experimental protocol. Results proved that the inertial system could improve the accuracy in detecting illegal steps. Through statistical classification, it was found that the proposed approach has achieved encouraging results in comparison with state of the art approaches and could be a good architecture to develop a valuable tool to assist experts.

Keywords: Experimental validation , Inertial sensor , Kansei engineering , Loss of ground contact , Race-walking , Statistical analysis

Ergonomic design of automotive seat is a very challenging task whose results may directly influence driver's comfort and safety. Seat comfort can be improved by identifying car-packaging solutions that allow an optimal driver's posture. In order to reduce the time and cost for testing, ergonomic analysis is carried out in virtual reality (VR) environment with digital human models (DHM) that can be used to simulate the anthropometric variability of a target population of users and thus verify the robustness of design solutions with respect to the anthropometrical noise factor. In this paper we illustrate a case study concerning the comfort improvement of a minicar packaging set up via robust ergonomic design (RED) with digital human models. The aim is the identification of the optimum levels for the seat control parameters that minimize the driver's comfort loss with respect to a preferred posture. The approach adopted for the analysis of data obtained from the virtual experiments is based on the joint generalized linear modeling of mean and dispersion of the driver's postural comfort loss (i.e. the ergonomic response of interest).

Keywords: Generalized Linear Models , Postural Comfort Loss , Robust Ergonomic Virtual Design , Seat Comfort Improvement

The way a person moves, either in a plain walk or performing a specific task, tells a huge quantity of information about his/her physical and, eventually, neurologic condition. A large part of a physiotherapist work of assessment is based on the qualitative evaluation, mainly visual, of a person's movements, in terms of balance, speed, control, force and other parameters. This research work aims at providing personnel involved in the rehab process with a quantitative method to assess the way movements are performed. A numerical measure of the performance, actually, allows easier and more precise assessment, eliminating bias due to subjectivity. To accomplish this goal two steps are required: 3D acquisition of the movement using a Motion Capture (Mocap) system, and analysis of collected data to extract or elaborate the final outcome in the form requested by the medical staff. The paper shows the way Mocap acquisition are performed and data are analyzed in the application with people having a complete spinal cord injury and using a wheelchair. The method has been tested with eight volunteers in the rehabilitation department of the Hospital Papa Giovanni XXIII in Bergamo, Italy.

Different sensor technologies are available for dimensional metrology and reverse engineering processes. Tactile systems, optical sensors, and computed tomography (CT) are being used to an increasing extent in various industrial contexts. However, each technique has its own peculiarities, which may limit its usability in demanding applications. The measurement of complex shapes, such as those including hidden and twisted geometries, could be better afforded by multisensor systems combining the advantages of two or more data acquisition technologies. In this paper, a fully automatic multisensor methodology has been developed with the aim at performing accurate and reliable measurements of both external and internal geometries of industrial components. The methodology is based on tracking a customized hand-held tactile probe by a passive stereo vision system. The imaging system automatically tracks the probe by means of photogrammetric measurements of markers distributed over a plate rigidly assembled to the tactile frame. Moreover, the passive stereo system is activated with a structured light projector in order to provide full-field scanning data, which integrate the point-by-point measurements. The use of the same stereo vision system for both tactile probe tracking and structured light scanning allows the two different sensors to express measurement data in the same reference system, thus preventing inaccuracies due to misalignment errors occurring in the registration phase. The tactile methodology has been validated by measuring primitive shapes. Moreover, the effectiveness of the integration between tactile probing and optical scanning has been experienced by reconstructing twisted and internal shapes of industrial impellers.

Keywords: industrial impeller , multisensor system , structured light scanning , tactile-optical measuring system

Orthodontic treatments based on removable thermoplastic aligners are becoming quite common in clinical practice. However, there is no technical literature explaining how the loads are transferred from the thermoformed aligner to the patient dentition. Moreover, the role of auxiliary elements used in combination with the aligner, such as attachments and divots, still needs to be thoroughly explained. This paper is focused on the development of a Finite Element (FE) model to be used in the design process of shape attributes of orthodontic aligners. Geometrical models of a maxillary dental arch, including crown and root shapes, were created by combining optical scanning and Cone Beam Computed Tomography (CBCT). Finite Element Analysis (FEA) was used to compare five different aligner's configurations for the same tooth orthodontic tipping movement (rotation around the tooth's center of resistance). The different scenarios were analyzed by comparing the moment along the mesio-distal direction of the tooth and the resulting moment-to-force ratio (M:F) delivered to the tooth on the plane of interest. Results evidenced the influence of the aligner's configuration on the effectiveness of the planned orthodontic movement.

Keywords: Anatomical modelling , Numerical analysis , Orthodontic aligner , Orthodontic tooth movement

Analysis of human-related aspects is fundamental to guarantee workers' wellbeing, which directly limits errors and risks during task execution, increases productivity, and reduces cost [1]. In this context, virtual prototypes and Digital Human Models (DHMs) can be used to simulate and optimize human performances in advance, before the creation of the real machine, plant or facility. The research defines a human-centred methodology and advanced Virtual Reality (VR) technologies to support the design of ergonomic workstations. The methodology considers both physical and cognitive ergonomics and defines a proper set of metrics to assess human factors. The advanced virtual immersive environment creates highly realistic and interactive simulations where human performance can be anticipated and assessed from the early design stages. Experimentation is carried out on an industrial case study in pipe industry.

Keywords: Digital Human Model , Ergonomics , Human-Centred Design , Sustainable Manufacturing , Virtual Reality

The paper describes the new smart noise monitoring system designed and implemented into the project named LIFE15 ENV/IT/000586 "Methodologies fOr Noise low emission Zones introduction And management" (LIFE MONZA). The prototype system has been designed keeping in mind the state of the art systems and the monitoring needs of the LIFE MONZA project. The designed system can be considered as a prototype according to the necessary customization in the designing of connections among the hardware components and in the definition of protocols to manage and post process of collected data. The prototype is expected to undergo quite a long testing phase (up to five years) during and after the LIFE MONZA project duration. In this paper, some details related to the designed network are reported. In particular, a detailed definition of the hardware components and specs, the transmitting data techniques, the specifications necessary to collect raw data are described. Furthermore some new procedures to periodically check the noise monitoring system performance are proposed.

Keywords: Environmental noise , Prototype , Smart monitoring system

Virtual museum (VM) systems are a very effective solution for the communication of cultural contents, thanks to their playful and educational approach. In fact, these appealing technological systems have demonstrated their usefulness and value in science centres and traditional museums all over the world, thanks to the fact that visitors can view digitized artworks and explore reconstructed historical places by means of VM-hosted installations. This paper presents a methodology, based on user studies, for the comparative evaluation of different design alternatives related to the user interaction with VM systems. The methodology has been validated by means of a testbed related to a VM system hosted at the “Museum of the Bruttians and the Sea” of Cetraro (Italy). The results of the user study demonstrate that this methodology can be effectively adopted in the development process of VM systems to optimize its outcomes in terms of usability and potential for entertainment and education.

Keywords: User study , User-centered design , Virtual museum systems , Virtual reality

The paper describes a user-centered design (UCD) approach that has been adopted in order to develop and build a virtual museum (VM) system for the “Museum of the Bruttians and the Sea” of Cetraro (Italy). The main goal of the system was to enrich the museum with a virtual exhibition able to make the visitors enjoy an immersive and attractive experience, allowing them to observe 3D archaeological finds, in their original context. The paper deals with several technical and technological issues commonly related to the design of virtual museum exhibits. The proposed solutions, based on an UCD approach, can be efficiently adopted as guidelines for the development of similar VM systems, especially when very low budget and little free space are unavoidable design requirements.

Keywords: Human-computer interaction , User interfaces design , User-centered design , Virtual museum systems

This paper describes a part of the contribution of the CoMAS project (“In situ conservation planning of Underwater Archaeological Artifacts”), funded by the Italian Ministry of Education, Universities and Research (MIUR), and run by a partnership of private companies and public research centers. The CoMAS project aims at the development of new materials, techniques and tools for the documentation, conservation and restoration of underwater archaeological sites in their natural environment. This paper details the results achieved during the project in the development of an innovative electric tool, which can efficiently support the restorers' work in their activities aimed to preserve the underwater cultural heritage in its original location on the seafloor. In particular, the paper describes the different steps to develop an underwater electric cleaning brush, which is able to perform a first rough cleaning of the submerged archaeological structures by removing the loose deposits and the various marine organisms that reside on their surface. The peculiarity of this work consists in a user centred design approach that tries to overcome the lack of detailed users' requirements and the lack of norms and guidelines for the ergonomic assessment of such kind of underwater tools. The proposed approach makes a wide use of additive manufacturing techniques for the realization and modification of prototypes to be employed for insitu experimentation conducted with the final users. The user tests have been addressed to collect data for supporting the iterative development of the prototype.

Keywords: Additive Manufacturing , Product Design , Underwater Applications , User centred design

This work concerns the growing interest in accessible tourism and describes the early stages of development of Gölem project. In particular, it takes into account accompanying activities of disabled people in mountain areas. Although literature and market analysis highlight the presence of different technical solutions used for the movement of disabled persons on rough terrains, there are only a couple of solutions based on the help of guides: Joëlette© and TrailRider©. Even if the use of these devices is generally satisfactory, our analysis has highlighted the presence of some limitations such as the difficulty of maintaining the lateral balance of the devices (which involves a considerable physical effort for the guides) and their reduced comfort for the passenger. This article describes the activities developed within the Gölem project. Its main goals are to design and to test an improved model of trekking/hiking wheelchair taking into account passengers comfort and better functionality of the device. At this moment, the design and modeling phases with the definition of dynamic parameters and of the suspension system of the device have been completed. The prototype implementation phase is in progress. Future activities will provide validation and field testing of the new solution with users.

Keywords: Accessible tourism , Comfort design , Disabled people , Mountain , Suspension system design , Trekking/hiking wheelchair