Human factors and ergonomics

Car design must very care comfort and driving pleasure. Nonetheless, the design choices are tested with subjective evaluations. In the present research, an objective measurement equipment for driving comfort assessment is proposed. The muscles activity of the driver in different maneuvers is considered the gauge of her/his feeling with the car. The activity of trapezius muscles of both shoulders is monitored by electromyography (EMG), through electrodes applied to her/his skin. The driver posture is monitored with a robust device for head tracking, using two 9-axis orientation sensors, including gyroscope. Real driving experiments are performed both with a luxury SUV and a high-end car. As expected, the first resulted more comfortable. The proposed equipment proved to be effective in assessing the driving comfort for different seat designs and car layouts.

Keywords: Comfort , Driveability , Electromyography , Head tracking

An airbag system is designed to reduce the accident outcome on the car occupants. The airbags deployment against manikins is severely tested according to international regulations. The accident scenarios with Out of Position (OP) occupants are critical since they can be hardly expected during design. The airbag deployment in these scenarios can be improved by developing adaptive strategies, provided that the Airbag Control Unit must be aware of the actual occupant position. The present research investigates a sensor system to monitor the occupants in an interactive Human-Car system. The driver position is monitored by pressure sensors, while an accelerometer enables to compensate for acceleration and noise. Real driving experiments in dynamic conditions are reported. The results prove that three OP conditions are effectively identified.

Keywords: Driver monitoring , Driving experiment , Intelligent vehicle , Out of position , Safety system

Future intelligent vehicles will be capable to monitor driver distraction while autonomous driving. However, in case of system fault, the intelligent vehicle must also manage an adaptive strategy for the Airbag Control Unit, since the airbag deployment against an Out of Position occupant can be additionally harmful. Thus, the present research work investigates a possibility to monitor the driver position as a robust information to an intelligent vehicle. A seat is sensorized with a map of pressure sensors. The system layout and setup are discussed in details. Signal processing strategy and real driving experiments are reported.

Keywords: Car seat , Driving experiment , Intelligent sensor , Intelligent vehicle , Pressure sensor , Safety system

This study proposes a novel quality function deployment (QFD) design methodology based on customers' emotions conveyed by facial expressions. The current advances in pattern recognition related to face recognition techniques have fostered the cross-fertilization and pollination between this context and other fields, such as product design and human-computer interaction. In particular, the current technologies for monitoring human emotions have supported the birth of advanced emotional design techniques, whose main focus is to convey users' emotional feedback into the design of novel products. As quality functional deployment aims at transforming the voice of customers into engineering features of a product, it appears to be an appropriate and promising nest in which to embed users' emotional feedback with new emotional design methodologies, such as facial expression recognition. This way, the present methodology consists in interviewing the user and acquiring his/her face with a depth camera (allowing three-dimensional (3D) data), clustering the face information into different emotions with a support vector machine classificator, and assigning customers' needs weights relying on the detected facial expressions. The proposed method has been applied to a case study in the context of agriculture and validated by a consortium. The approach appears sound and capable of collecting the unconscious feedback of the interviewee.

Keywords: 3D facial expression recognition , Emotional design , Quality function deployment (QFD) , User-centred design

An important area of risk management practice for manufacturing companies relates to the prevention of injuries and musculoskeletal disorders (MSDs). The greater benefits can be achieved where a preventive approach is used, based on ergonomic design of workplaces and attention to human requirements and limitations as well as human-machine interaction principles. The research aims at providing a pragmatic approach to support the application of ergonomic risk management in practice. It defines a multipath methodology to investigate human factors impacting on safety by considering the specific workspace, the adopted tools, the overall production environment and the workers' activity. An industrial case study is described to illustrate the methodology and demonstrate the benefits for companies. Results suggest that the proposed multipath methodology allow to effectively assist analysts in the definition of crucial risk factors and selection of proper ergonomics assessment and measurement tools according to the specific context of application.

Keywords: Design methods , Digital manufacturing , Ergonomics , HCD , Human-centred design , Risk management

This paper describes the conceptual model and the implementation of an emotion aware system able to manage multimedia contents (i.e., music tracks) and lightning scenarios, based on the user's emotion, detected from facial expressions. The system captures the emotions from the user's face expressions, mapping them into a 2D valence-arousal space where the multimedia content is mapped and matches them with lighting color. A preliminary experimentation involved a total of 26 subjects has been carried out with the purpose of assess the system emotion recognition effectiveness and its ability to manage the environment appropriately. Results evidenced several limits of emotion recognition through face expressions detection and opens to several research challenges.

Keywords: Affective computing , Ambient intelligence , Emotion detection , Emotion recognition , Emotion-aware system , Face expression recognition , Smart environment

The optimization of the aeronautical structures manufacturing is one of the most challenging tasks in development of a new aircraft. Nowadays, aeronautical industries are supporting researches deal with the development of new assembly approaches which aim at increasing efficiency and reducing cost of the processes. The work here presented focused on definition of a Jig-less assembly procedure of the 'Integrated Main Landing Gearbox' (ITEM B). The project aims to develop a new generation of Lower Center Fuselage with an innovative landing system integrated in the fuselage itself. The ambition of ITEMB is the creation of a single integrated structure in composite material of the gear bay that reduces assembly costs, optimizing and integrating the entire design, construction and maintenance of the aircraft. The approach here described is based on the integration of different engineering disciplines, as such as the tolerance statistical prediction, the ergonomics, digital human modeling, manufacturing and measurement technologies. In particular, through an appropriate ergonomic analysis, an innovative assembly process of the gear bay was developed and optimized in a virtual environment pointing out the advantages and disadvantages with respect to a traditional assembly cycle. The assembly process is based also on the implementation of the assembly tolerance prediction.

Keywords: CAD , Determinant Assembly , Ergonomics , Jig-less approach , Tolerance statistical prediction , Variational assemblies

The percentage of passengers that prefer travelling in groups is increasing. In most vehicles, passengers sit side by side and need to turn their body to be engaged in the conversation with their fellow travellers. However, rotating the body could lead to discomfort which influences conversation quality. The aim of this research is to study the effect of seat configuration on the (dis)comfort experience, conversation quality and posture. Experiments in which participants were asked to talk to each other while sitting at the same distance (1 m) were conducted in four seating arrangements (with seat-belts on), where the angle between the forward directions of two seats were positioned at 0° (side by side), 22.5°, 90° and 120° (almost opposite each other), respectively. Optical tracking has been deployed and the collected data were processed with MatLab® to acquire postural angles over time. Questionnaires were also used to evaluate the perceived (dis)comfort and the quality of the conversation. Experiment results indicate that the 120° configuration scored the best in the overall comfort and the quality of conversation, but only slightly better than the 90° configuration. Practitioner summary: Seating side by side is not optimal to have a comfortable conversation with your seatmate. To improve comfort and quality of conversation in future vehicles, we tested four seating arrangements analysing the effect of seat layout on (dis)comfort experience. Statistical analysis of objective and subjective data shows the optimal configuration for a comfortable conversation. Abbreviation: LPD: localized postural discomfort; PDF: probability density function; OCRA: occupational repetitive action.

Keywords: Comfort , conversation quality , seat layout , seating arrangement , vehicle design

This research aims to study the effect of seat and/or backrest rotation on comfort and quality of conversation. Different sitting arrangements were tested to study the effect of the seat layout on: 1) (dis)comfort experience; 2) conversation quality and 3) postures. Two seats were arranged in different angles (0° 45° 90° and 180°) at the same distance (1 m) and participants were asked to talk to each other. The participants' postures were acquired by using cameras and markers on the participants' body. Questionnaires were used to rate the perceived (dis)comfort and quality of conversation. Results show that 90° configuration scored the best both in overall comfort and quality of conversation; while the 0° configuration scored the lowest in both ratings. A strong correlation was established between high comfort and good quality of conversation.

Keywords: Comfort , Communication , Quality of conversation , Sitting arrangement

Manufacturing ergonomics refers to the application of ergonomic principles and human factors analysis to the design of manufacturing tasks with the final aim to optimize the workers' wellbeing and guarantee the expected process performance. Traditional design approaches are based on the observation of individual workers performing their jobs, the detection of unnatural postures (e.g., bending, twisting, overextending, rotating), and the definition of late corrective actions according to ergonomic guidelines. Recently, computer-integrated simulations based on virtual prototypes and digital human models (DHMs) can be used to assess manufacturing ergonomics on virtual manikins operating in digital workplaces. Such simulations allow validating different design alternatives and optimizing the workstation design before the creation, and pave the way to a new approach to manufacturing system design. The present paper aims at comparing different computer-integrated set-ups to support the design of human-centred manufacturing workstations. It defines a protocol analysis to support workstation design by analysing both physical and cognitive aspects, and applies the protocol within different digital set-ups. In particular, the study investigates a 2D desktop set-up using standardized DHMs and a 3D immersive mixed reality set-up based on motion capture of real workers' acting into a mixed environment, comparing them with the traditional approach. An industrial case study focusing on design optimization of a manufacturing workstation in the energy industry is used to test the effectiveness of the two digital set-ups for the definition of re-design actions.

Keywords: Digital human models , Human factors , Human-centred design , Manufacturing ergonomics , Mixed reality

Today manufacturing enterprises aim not only to deliver high-value, cost-effectively products in a sustainable way, but also to consider the quality of the working environments. The analysis of human factors, which strongly affect time and quality of manufacturing processes, are crucial for satisfying people involved in the manufacturing process and making them safe, preventing diseases, errors and excessive workload. The paper presents a structured procedure to automatically extract data from virtual analysis made by digital manufacturing tools and measure a set of indicators to validly assess manufacturing ergonomics. The research considers the state of the art in manufacturing ergonomics and defines a set of indicators suitable for manufacturing manual operations, focusing on assembly tasks. Furthermore, it defines a methodology to automatically extract data valorising the selected indicators and an application, based on Visual Basic, to generate the specific task list and related assessment. The result is a rapid and objective assessment, independent from the experience of the user, which can be executed during process design. The procedure has been applied to an industrial case study, where the manual assembly of cabin supports on the tractor chassis has been analysed in order to correct the most uncomfortable steps and obtain a more ergonomic process. A decrease of the EAWS score, calculated with the proposed method, allowed to validate the proposed solution, suggesting a redesign of the assembly cycle to improve the working conditions. Such a procedure anticipates the analysis of the workers' wellbeing during the design stage to support the definition of human-centric manufacturing processes, simplifying and accelerating the assessment activities. © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.

Keywords: Digital Manufacturing , Human Factors , Human-Centered Design (HCD) , Manufacturing Ergonomics , Virtual Engineering

Human-centred design is based on the satisfaction of the user needs mainly related to performances, interaction, comfort, usability, accessibility, and visibility issues. However, the “real” user experience (UX) is hidden and usually difficult to detect. The paper proposes a multimodal system based on the collection of physiological and anthropometrical performance data on field and within a mixed prototyping set-up. The mixed environment makes users interact with virtual and digital items and users' performance to be capture and digitalized, simulating human-machine interaction, while physiological and anthropometrical data collection allows to objectify the users' physical and mental workload during task execution. Such a system has been applied to an industrial case study focusing on agricultural machinery driving and control to support the definition of a new cabin and its control board, in terms of seat features, commands' positioning and grouping, and positioning of additional devices.

Keywords: Ergonomics , Human-centred design , Human-machine interaction , Mixed prototyping , User experience

Driving is a high-demanding task, related to human capacity, required performance and events occurring in the external environment. Mental workload depends on numerous factors: task difficulty, task complexity, level of traffic, additional activities required by the driving action or imposed by the driver, the contextual conditions, as well as the individual response to stress. The study of driver's workload is crucial in guiding future car design, in order to improve the user experience, comfort as well as driving performance and safety. Indeed, if task demands are too high in relation to the user's capabilities, errors may occur and may become critical for safety. The present paper defines a transdisciplinary approach based on monitoring the driver's workload during driving tasks in order to map the perceived user experience, and finally understand the interaction between the driver and the car systems. The approach is based on three layers: the human conditions to detect, the vital parameters to be monitored, and the adopted monitoring technologies. The paper proposes: a protocol to monitor the driver's workload during both real and simulated tasks, a technological set-up including physiological and performance data collection, and a proper data elaboration strategy. The key findings are: the selection of the most relevant subjective and objective parameters to measure the driver's mental workload, the definition of a preliminary technological set-up for monitoring the workload during simulated driving, and the evaluation of the effects of task complexity and of a secondary task on driver's performance. The research paved the way to further studies about how to miniaturize and embed sensors inside the car for a less intrusive application during real driving. Results can also be used to assess the interaction with car devices and to compare different design alternatives.

Keywords: Human Factors , Human-Centered Design , Mental workload , Transdisciplinary Engineering , User experience

Armrest in tractors is like a control dashboard for trains or airplanes; it is fundamental for managing and properly setting the machine. For this reason, there is the need to adjust it for each operator's size and application. Nowadays, armrests are usually very big and intrusive, because they are full of controls and sometimes they are not really comfortable for each user size and need. Furthermore, agricultural equipment is often used under difficult conditions: steep terrain and extreme weather conditions require products able to guarantee total safety and maximum comfort, minimizing the risk of human error caused by excessive fatigue. The aim of the project is to create an “ergonomic - compact armrest”, focused on the users' need, with the application of Ergonomics and Human Machine Interface (HMI) principles, shifting the focus from how a machine works to how a task is performed. For designing the “ergonomic - compact armrest” a new system based on the collection of “real” users biomechanical performance within a virtual lab was adopted. In this virtual environment, it was possible to test many different configurations of controls, checking which controls are mostly used, and measure the comfort index and mental work load for each configuration. On this basis, a “digital twin” of the user was created, consisting in a set of scalable virtual manikins that can interact with virtual items, and a comfort index was defined as an objective and reliable measure to evaluate workload during any task execution. Thanks to this new methodology, the “ergonomic - compact armrest” is 30% smaller than the previous one, but at the same time it accommodates in comfort the 95% of the population size, keeping on board only frequent controls positioned in ergonomic way. The results of this study could be used for other tractors controls layout design, so that human comfort can be improved and any task can be felt as natural as possible, encouraging good posture and safe behaviours, and reducing cost of prototypes and time to market.

This work proposes a human computer interface system using a motion capture device, for assisting in CAD modeling and designing. The leap motion controller input data serves as an interactive tool which is transformed to surface representation of NURBS surfaces. Acquiring the sensor data is done by analyzing the images using a feature recognition module which in this work was updated and enhanced. Joints of hands and fingers are sufficed, and define recognized 3D image of a human hand. To use relevant information from the Leap Motion device, it is mandatory to interpret and map the input sensor data into 3D software coordinate system. This is done by implementing various transformations and a normalization procedures. Methods corresponding between these representation are developed in this work, to reduce noise thus providing accuracy. The DOF provided by the definition of the NURBS parametric surfaces and the Leap Motion Controller provide flexible design characteristics.

Keywords: Human Computer Interaction , Leap Motion Controller , NURBS surfaces , Virtual CAD

Over the past few years, foam materials have been increasingly used in the passive safety of sport fields, to mitigate the risk of crash injury. Currently, the passive safety certification process of these materials represents an expensive and time-consuming task, since a considerable number of impact tests on material samples have to be carried out by an ad hoc testing apparatus. To overcome this difficulty and speed up the design process of new protective devices, a virtual model for the low-velocity impact behaviour of foam protective mats is needed. In this study a modelling approach based on the mesh-free Element Galerkin method was developed to investigate the impact behaviour of ethylene-vinyl acetate (EVA) foam protective mats. The main advantage of this novel technique is that the difficulties related to the computational mesh distortion and caused by the large deformation of the foam material are avoided and a good accuracy is achieved at a relatively low computational cost. The numerical model was validated statistically by comparing numerical and experimental acceleration data acquired during a series of impact events on EVA foam mats of various thicknesses. The findings of this study are useful for the design and improvement of foam protective devices and allow for optimizing sports fields' facilities by reducing head injury risk by a reliable computational method.

Keywords: EFG method , Foam protective mats , Impact testing , Sports safety

In the field of movement disorders, each disabled person is different for both motor performance for functional requirements and expectations. This paper describes the development of a personalized device for a student with spastic quadriplegia at Federico II. This device is an Alternative Augmentative Communication system and it consists of hardware and software, which have been adapted to the individual characteristics of the student. According to participatory design and using the task analysis, we proceed to the hardware prototyping and to the software interface improving. An approach based on Analytic Hierarchy Process and Multiple-Criteria Decision Analysis is used. Tests under laboratory conditions are performed for evaluating the usability index of the device. Considering the data analysis, some critical issues are identified. The knowledge acquired in the case study is a point of strength of the proposed paper because it can be re-used for other persons with severe motor disabilities to improve their inclusion, integration and participation and to carry out tasks in different areas of application with minimum stress and maximum efficiency and effectiveness.

Keywords: Alternative augmentative communication , Participatory design , Spastic quadriplegia , Usability assessment

In this paper we present the design, prototyping and validation of a novel adjustable foot stretcher for indoor rowing training. The overall process is user-centered, in the sense that the athletes are directly involved in all the phases of the product development, from conceptual design to evaluation and validation. The conceptual design starts from well-known rowers needs. Accordingly, two design factors are selected to parametrize the prototype, namely the inter-axle spacing feet and the foot angle. The experimental evaluation and validation involve two phases, one based on a quantitative analysis of the performance, one based on subjective questionnaires submitted to the athletes. The performance-based analysis comprises the derivation of three pressure indices and one power transmission index. Indeed, the subjective analysis regards the users comfort and power transmission feelings. The results of both evaluations testify that an improvement in performance and comfort of the indoor rowing training session can be achieved.

Keywords: Performance evaluation , Robust design , Sports engineering , Sports equipment and technology , User-centered design

The use of Augmented Reality (AR) technologies is the new challenge of management models born under the “Industry 4.0” paradigm. The aim of the work is to evaluate the usability of two types of AR devices (tablet and see-through) employed in the training and information activities of workers according to the ISO/IEC 9126 and ISO 9241 standards. Starting from the state of the art, evaluating market and competitors and developing different concepts of interfaces, a dedicated application was programmed and, then, the usability of such devices for the professional figures involved was evaluated through experimental tests. Two reference scenarios were defined, the Department of Industrial Engineering of University of Naples Federico II and INAIL (National Institute for Insurance against Accidents at Work) laboratories, an user interface was designed and developed, as an aid in the drafting of the document for risk evaluation and subsequent training of workers. The activity is part of the IDEE Project (Interactive Design for Ergonomics), born by the collaboration between Joint Lab IDEAS and Contarp-INAIL-Regional Management for Campania. The data analysis allowed to evaluate the goodness of the devices and the degree of satisfaction in their use on the basis of the sample of users who conducted the tests. The use of AR devices produces better results than paperwork in terms of efficiency and effectiveness, but not all devices produce appreciable results in terms of user satisfaction. Although AR technologies are mature, the tasks need to be carefully defined to avoid rejection phenomena. The strong expectation, that they generate in potential users, risks to remain disappointed today for some usability limits found in currently available devices. It is necessary to start testing in pilot applications in various industrial fields in order to capture in time and adequately support this opportunity of innovation in Italy.

Keywords: Augmented reality , Risk assessment , Usability