Human factors and ergonomics

This paper describes a mixed reality application for the assessment of manual assembly of mechanical systems. The application aims at using low cost technologies and at the same time at offering an effective environment for the assessment of a typical task consisting of assembling two components of a mechanical system. The application is based on the use of a 6-DOF interaction device that is used for positioning an object in space, and a haptic interface that is closer to reality and is used for simulating the insertion of a second component into the first one while feeling a force feedback. The application has been validated by an expert user in order to identify the main usability and performance problems and improve its design. © 2009 Springer Berlin Heidelberg.

Keywords: Haptic-based interaction , Virtual Manual Assembly , VR system evaluation

Recent analyses on the uninhabited aerial vehicle (UAV) accidents revealed that several kinds of human-system control problems occur in current UAV missions. Therefore, a design of the man-machine interface that allows for an efficient and effective interaction between the operator and the remote vehicle becomes one of the challenges in the development of more reliable UAVs. This paper presents a first implementation of an advanced interface for UAV ground control station based on a touch screen, a 3D virtual display, and an audio feedback message generator. The touch screen is used to send high level commands to the vehicle, the 3D virtual display provides a stereoscopic and augmented visualization of the complex scenario in which the vehicle operates, and the audio feedback message generator informs the operator about any change in operational scenario. The hardware/software architecture of the interface also includes a planning algorithm and a generic vehicle model. The interface has been tested by simulating several UAV missions. The results have shown that the interface requires an adequate level of workload to command the vehicle and allows the operator to build a good level of awareness of the state of the vehicle under his or her control, as well as of the environment in which it operates. © 2009 by the Massachusetts Institute of Technology.

The ability to perform autonomous mission planning is considered one of the key enabling technologies for uninhabited aerial systems. Subsequently, a big effort is made in the development of algorithms capable of computing safe and efficient routes in terms of distance, time, and fuel. In this paper an innovative 3-D planning algorithm is presented. The algorithm is based on considering the uninhabited aerial systems representation of real world systems as objects moving in a virtual environment (terrain, obstacles, and no fly zones), which replicates the airspace. Original obstacle avoidance strategies have been conceived to generate mission plans that are consistent with flight rules and with the vehicle performance constraints. Simulation test results show that efficient routes are computed in a few seconds.

We present a novel approach, called tangible digital master (TaDiMa), based on a flexible access to Product Lifecycle Management (PLM) database using a tangible/graphical user interface and augmented reality. We developed and tested a technical drawing template with automatically embedded markers for augmentation. We embedded the Mozilla FireFox engine into our annotation system for the integration of web 2.0 applications in the AR environment. We also extended the concept of web feed to PLM for notification of technical contents. We implemented a dynamic labelling management with view-driven filtering and placement. We also present a tangible management for layers visualization and users access by marked tokens. We validated the TaDiMa approach in a selection of possible scenarios for different PLM applications. The main benefit of the TaDiMa system is the easy and low-cost integration in the product lifecycle process. © 2009 Springer-Verlag.

Keywords: Industrial augmented reality , PLM , Tangible interfaces , Technical drawings and annotations

Visuo-haptic mixed reality consists of adding to a real scene the ability to see and touch virtual objects. It requires the use of see-through display technology for visually mixing real and virtual objects, and haptic devices for adding haptic interaction with the virtual objects. However, haptic devices tend to be bulky items that appear in the field of view of the user. In this work, we propose a novel mixed reality paradigm where it is possible to touch and see virtual objects in combination with a real scene, but without visual obtrusion produced by the haptic device. This mixed reality paradigm relies on the following three technical steps: tracking of the haptic device, visual deletion of the device from the real scene, and background completion using image-based models. We have developed a successful proof-of-concept implementation, where a user can touch virtual objects in the context of a real scene. ©2009 IEEE.

Keywords: H.5.1 [information interfaces and presentation]: multimedia information systems - artificial, augmented, and virtual realities

How can car designers evaluate device's position inside a car today? Today only subjective tests or "reach-ability" tests are made to assess if a generic user is able to reach devices, but it's no longer enough. The aim of this study is to identify an instrument (index) that is able to provide a numerical information about the discomfort level connected with a posture that is kept inside a car to reach a device, by this instrument it should be possible not only judge a posture, but also compare different solutions and get rapid and accurate evaluations. In the state of the art there are many indexes developed to evaluate postural comfort (like RULA, REBA and LUBA [3, 4, 5]) but none of them has been realized to evaluate postures' conditions that can be detected inside a car, so their evaluations cannot be acceptable. There are also many other studies (like Porter and Gyi, Krist, Grandjean, Rebiffe, Dreyfuss 2D and 3D) which deal with postural comfort inside car, but they have only assess neutral angles and ranges of comfort, so their evaluations are qualitative and discontinuous. For these reasons it has been realized a new instrument (implemented by our research group using Matlab™) to give the wanted numerical evaluation; it is based on an human scale manikin that can reproduce each user and each posture which can be introduced directly or imported from a digital human modeling (DHM) software (like JACK™ developed by U.G.S.), on discomfort functions (one for each degree of freedom of the manikin) and on a method (based on the distribution of the weights of the human body on the different joints) to aggregate them and return total discomfort values. © 2009 SAE International.

The purpose of this study was to establish whether players' perceptions in football competitions played on artificial turf can be influenced by the pitch under examination, the kind of infill material used, the weather conditions and by player's role in the team. A multifactorial statistical analysis was made of the results obtained from over 1600 U.E.F.A. questionnaires completed by amateur footballers. Pitch and weather factors were demonstrated to be relevant to the aspects investigated. Conversely, the players' role and the infill material were significant for only a few aspects; for each variable, the analysis indicated the most favourable conditions. Overall, the analysis provided insight into amateur players' favourable feelings about artificial turf, compared with its natural alternative (actually made of earth, without grass in the case of amateur players). © 2008 Elsevier Ltd. All rights reserved.

Keywords: Amateur football players , Artificial turf , Ergonomics , Survey

The present work deals with the re-designing of a locomotive, according to in force European standards, in the field of active and passive safety. The paper illustrates the use and the management of heterogeneous product information (2D drawings, technical documentation, photos), Virtual Reality tools and digital human models, for the re-designing of a locomotive, using a collaborative approach with a total absence of the reference digital models. The project development has been organised using a top-down approach in a collaborative environment. Finally, by means of the digital prototype of locomotive, a series of aesthetic, functional and ergonomic analyses, in virtual environment, has been performed. © Springer Verlag France 2007.

Keywords: Collaborative design , Ergonomics , Top-downapproach , Virtual reality

Virtual Reality (VR) systems provide new modes of human computer interaction that can support several industrial design applications improving time savings, reducing prototyping costs, and supporting the identification of design errors before production. Enhancing the interaction between humans and virtual prototypes by involving multiple sensorial modalities, VR can be adopted to perform ergonomic analysis. The main problems deal with the evaluation both of functional and cognitive sample users behavior as VR interfaces influence the perception of the ergonomic human factors. We state that ergonomic analysis performed in virtual environment can be successful only if supported with a structured protocol for the study both of functional and cognitive aspects and with the proper VR technologies combination that answers to the specific analysis tasks. An ergonomic analysis protocol is presented. It allows the assessment of the consumers/ response in term of behavioral and cognitive human factors, comprehending both operational and emotional agents. The protocol is also used to identify the best combination of visualization and haptic interfaces to perform the analysis. An experimental example, belonging to house appliances field is adopted to investigate the application of the protocol in the virtual set up. Copyright © 2008 by ASME.

In this study, a methodology based on co-simulation was developed for the multibody parametric modelling of a motorcycle with an anthropomorphic model of the rider. This co-simulation uses two different software programs, integrated to ensure a complete exchange of information between them in real time. The paper reports the effects induced by the movement of the rider's body on the dynamics and performance of a motorcycle. The legs of an anthropomorphic model were used as kinematics to control transverse movements of the motorcycle. The control system inputs are the geometric characteristics of the road (length, width and radius of curvature) and the speed of the vehicle along the track. For the dynamic behaviour of the motorcycle, the only channels currently operated by the control system are steering angle and engine torque, which are determined in accordance with the input parameters.

Keywords: Control , Dynamic , Motorcycle , Multibody , Rider

Considerable progress has been made in the development of Velocity Prediction Programs (VPPs) suitable for analysis of racing yacht performance. In addition, investigations on yacht dynamics (i.e. optimal tacking procedure) are now available. While these tools will no doubt be further refined and computations speeded up, there is also a need to assess the performance of the yacht's helmsman and crew. The scope of the present study is the prediction of the performances of a yacht-crew system as a whole, by deriving numerical models for human behaviour alongside with those referred to the physics of yacht motion. The latter issue, the mechanical side of the problem, is analysed by solving yacht equations of motions in the time domain; crew inputs in terms of yacht steering and sail trim are considered. The yacht-crew system can sail a racecourse in an arbitrary wind pattern, according to strategic rules and given decision making schemata. © 2008: Royal Institution of Naval Architects.

Large stereo displays and 3D input devices have proved significant productivity benefits in CAD, but they have also shown interaction weaknesses. We present a novel approach for pointing CAD entities with a 3D cursor on a wall-like stereoscopic display. We proved that the user error is affected by anisotropy, hence we present an enhanced snap tool called eSnap. This tool uses an elliptic metric for 3D cursor proximity. The provided results demonstrate a significant improvement in user performances and can be used as a guide for the development of user interfaces in emerging 3D displays. Copyright © 2008 Inderscience Enterprises Ltd.

Keywords: 3D input , CAD interaction , HCI , Large stereo displays , LSDs

In the current demanding global marketplace, ensuring that human fit, form and function are comprehensively addressed, is becoming an increasingly important aspect of design and, in particular, obliges the most important automotive industries to develop more flexible assembly lines and better methods for PLM solution. In the meantime, designers attempt to elaborate product development methodologies that conform health and safety standards while still maximizing the productivity. The aim of this work consists in developing a methodology based on preventive ergonomics and feasibility analyses of assembly tasks, simulating a work cell, in which acts a digital human model (manikin), in order to maximize human safety and performance and analyze manikin interaction in the virtual environment. In ergonomic analyses the OCRA protocol will be used, evaluating different involvement degrees of upper limb segments. The methodology is carried out by ergonomic tool of DELMIA software, using Digital Human Models technology. © 2008 International Federation for Information Processing.

Keywords: Digital human models , Ergonomic analysis , OCRA protocol , PLM solution

In the last years the most important automotive OEM have given more importance to job organization and optimization in the plants for productivity and legal reasons. The continuous request to produce different new models in few years oblige OEM to develop more flexible assembly lines and better methods for job planning on the same lines. In the meantime, safety norms and product quality reasons request to improve working condition also according to international standards. In this paper, the authors show a new method for process design with the final goal to optimize assembly tasks. The method is based on the possibility to apply preventive ergonomics and feasibility analysis of the assembly task through a virtual simulation investigating general feasibility of the task and risks of muscle-skeletal pathologies from incongruous postures and movements. Using Digital Human Models (DHM) and Virtual Reality (VR) tools, it is possible to simulate manual assembly tasks in a very preliminary moment of the process development where designers and engineers have only virtual models to check assembly feasibility and to design the final bill of process. Through the use of virtual manikins, designers can vary workers movements to solve complex problems related to human movements and posture recognition bringing more realistic and reliable simulations to systematically investigate workplaces for a wide variety of users and operative solutions. On the methodological point of view, a special attention has been given to ergonomics evaluation methods that, usually, have an experimental nature and therefore specific adaptations are required to use them on digital humans in virtual environments. In the paper, the authors show an application of the new method to an interesting case study. The simulations suggest new solutions which bring to a more ergonomic and efficient task. Copyright © 2008 SAE International.

This paper presents an approach to evaluate product ergonomics using virtual humans. This work has been carried out to demonstrate that virtual humans are an important tool to improve virtual prototyping functionalities and, above all, to increase ergonomics and safety of products. A test methodology has been defined and several simulations have been made, varying anthropometry and workplace conditions. Two case studies that can demonstrate the validity of the approach are described. The first concerns instruments of a car for which the geometric model of the interior and a commercial virtual human have been used. The second case study concerns the external visibility of a farm tractor that can be equipped with different tools to accomplish to various tasks (e.g. harvesting and fruit picking). The results obtained are images that represent what the virtual human sees and permit to compare and validate different design solutions.

Keywords: Ergonomics , Internal and external visibility , Virtual manikin

Recently, the problem to estimate the felt comfort associated with the vibrations on city buses has been put in evidence, with particular attention about the infrastructurevehicle interactions. The aim of this work is to evaluate the effects of the traffic calming devices on the passengers of the public transports by vibration measurements. A self-sufficient measurement system has been implemented. It links each measurement with a geographical information resulting from a Global Positioning System (GPS), and permits to obtain a map of a comfort index directly, using the Geographic Information System (GIS). The presented system is based on widely used hardware components, i.e. a laptop computer, a commercial GPS receiver and three mono-axial servo-accelerometers. A custom software has also been developed.

Keywords: Comfort index , GIS , Vibration measurements

Virtual Reality and related technologies are becoming a common practice in the design industry in general and more specifically in the automotive field. By the joined use of virtual prototyping methodologies it is possible to achieve the reduction of the time-to-market, as well as the costs deriving from the creation of physical prototypes. Ergonomics tests conducted in Virtual Reality environments can be successfully used to influence the design of products. We have set up a mixed reality environment that allows us to simulate and test postural aspects as well as various levels and modalities of users' interaction. In order to achieve a performing interaction, correct registration and visualization parameters must be carefully set for preventing possible interaction errors, such as pointing with precision to the assigned target. The paper presents a methodology for tuning stereoscopic properties of the mixed reality environments used for ergonomic tests of a car interior in order to achieve correct visualization and positioning parameters. The environment includes a virtual human controlled by an optical motion tracking system, physical objects onto which the graphic virtual environment is superimposed, and a rotatory haptic device for controlling the car on-board infotainment. interface. © The Eurographics Association 2007.

The field of computer graphics is greatly increasing its overall performance enabling consequently the implementation of most of the product design process phases into virtual environments. The deriving benefits of using virtual practices in product development have been proved intrinsically highly valuable, since they foster the reduction of time to market, process uncertainty, and the translation of most prototyping activities into the virtual environment. In this paper we present the developed platform in mixed environment for ergonomic validation. Specifically we defined a methodology for testing both aspects related to design and ergonomic validation by allowing the tester to interact visually and physically with the car dashboard control devices and related interface by the mean of a rotatory haptic device. By experimental session it has been highlighted that it is possible gathering qualitative data about the design, and finding typical occlusion problems, but also quantitative data can be collected by testing the infotainment interface and the consequent users' distraction during the device use. © Springer-Verlag Berlin Heidelberg 2007.

Keywords: Ergonomic analysis , Mixed environments , Tactons

The challenge of racing one-design yachts is to maximize the performance of the yacht within the scope allowed by the relevant regulations. Such tuning of the yacht, for a well-policed rale, should only make possible small gains. The main area of possible performance gain is in how best an individual sailor or crew can fine tune their racing strategy. The ability to model such strategic decisions requires an understanding of both the physical behaviour of the yacht and how an individual sailor makes such decisions. The present study seeks to predict the performances of a yacht-crew system as a whole by deriving numerical models for human behaviour alongside those referring to the physics of yacht motion. The former aspect, a transposition of athletes' psychology within the racing scene, is investigated by means of questionnaires submitted to skilled athletes and structured interviews with sailing coaches. The latter issue, the mechanical side of the problem, is analysed by solving yacht equations of motions in the time domain; crew inputs in terms of yacht steering and sail trim are considered. The paper presents results from simulations in which the yacht-crew system can sail a racecourse in an arbitrary wind pattern, according to strategic and tactical rules derived by common practice and following the decision making schemata obtained above.

A sailing simulator is described that takes into account human factors with respect to strategic decisions during a race. Models for yacht-crew interaction have been designed and implemented for the helmsman and the sail tailers, as well as a 'routing engine' that solves problems of a strategical and a tactical nature (e.g. navigation in windshifts, collision avoidance). One or more users can interact with the simulator, so that their behaviour and decision-making process can be recorded, analyzed and compared to that of the automatic crews. The software was implemented in MATLAB-Simulink and consists of two modules: 'Robo-Yacht', for solo and drag races, and 'Robo-Race' for fleet regattas. In the latter case, a real-time animation of the race is delivered to the user in real-time within a virtual reality environment. A series of case studies are presented that demonstrate realistic interactions between a yacht whose decisions are made by a sailor and a mini fleet of autonomous yachts.