Human factors and ergonomics

Advanced measurement systems and techniques from neuroscience are used in this work to extrapolate reduced- order muscle activation patterns corresponding to the execution of overhead tasks classic of automotive industry. The approach is based on the analysis of electromyographic (EMG) signals measured from muscles of the upper limb. The preliminary experiments show that, for the selected tasks, one muscle synergy could account for > 98% of the total muscle activation. This approach might pave the way towards the development of bionic, synergy-based upper limb wearable robots for augmenting human performances in industrial workplaces.

Keywords: EMG , muscle synergies , wearable robots

The musculoskeletal disorders represent one of the most common problems in industrial environment; they impact the health of workers and employees. In this work we present a preliminary study towards the use of biomechanical models for improving classic methods for ergonomic assessment in industry. To this end, we use OpenSim, a software for biomechanical simulation and analysis. With OpenSim, we reconstruct the human motion corresponding to the execution of industrial tasks, performed in laboratory settings. In particular, we compute the evolution over time of the joint angles that, according to a classic observation method for ergonomic assessment, are needed to evaluate the risks associated to the musculoskeletal disorders for the upper limb.

Keywords: biomechanics , digital human model , ergonomics , industry

The present paper deals with collaborative robotics and proposes to enable collaborative workstations by means of the critical study of the in-force standards on Human Robot Cooperation. The paper introduces the anthropocentric paradigm and presents a new basis for designing workstation composed by two key concepts: (i) human and robot spaces are elementary spaces able to generate all other spaces; (ii) dynamic variations of the elementary spaces in terms of shape, size and position occur. Moreover, dynamic positions of human and robot spaces enable collaborative operations in case of mobile robots.

Keywords: anthropocentric design , dynamic workspace , human-robot interaction , safety

In this work we present a study for the experimental reconstruction of the human shoulder torque in the sagittal plane, since this is usually overloaded in industrial overhead tasks. To this end, we measure the three-dimensional motion of the human upper limb while performing selected movements using an optical motion capture system. Then, using a skeleton model implemented in one of the most common software for industrial ergonomic assessment, we reconstruct the shoulder angle and torque in the sagittal plane. A possible exploitation of this reconstruction strategy is presented for active compensation of this torque. The implementation of this simple strategy in a custom developed assistive device could augment human workers in performing repetitive jobs.

Keywords: biomechanics , digital human models , human motion analysis , industrial assistive devices

We propose to use an industrial redundant manipulator (KUKA LBR iiwa robot) as a haptic device to provide high force feedback for an orthopedic surgeon while performing the reaming of the acetabula in a virtual environment. Real experiments have been performed to validate the virtual reality training framework. The results show that the system resulted to be intuitive and reliable from the users experience.

Keywords: medical robotics force feedback virtual reality training

This work focuses on an innovative training methodology based on the use of Virtual ergonomics and “serious games” in the field of occupational safety. Virtual Ergonomics was chosen as an effective and convincing tool for disseminating the culture of safety among the workers, while a “serious game” was developed to train operators on specific safety procedures and to verify their skills. The results of the experimentation in a real industrial case study showed that, compared to the traditional training methodology, multimedia contents and quantitative ergonomic analyses improve the level of attention and the awareness of the operators about their safety. On the other hand, Serious games turned out as promising tools to train the workers about safe operating procedures that are difficult to implement in a real working environment.

Keywords: Ergonomics , Occupational safety , Serious game , Virtual humans , Virtual reality

Nowadays, healthcare centers are not familiar with quantitative approaches for patients' gait evaluation. There is a clear need for methods to obtain objective figures characterizing patients' performance. Actually, there are no diffused methods for comparing the pre- and post-operative conditions of the same patient, integrating clinical information and representing a measure of the efficiency of functional recovery, especially in the short-term distance of the surgical intervention. To this aim, human motion tracking for medical analysis is creating new frontiers for potential clinical and home applications. Motion Capture (Mocap) systems are used to allow detecting and tracking human body movements, such as gait or any other gesture or posture in a specific context. In particular, low-cost portable systems can be adopted for the tracking of patients' movements. The pipeline going from tracking the scene to the creation of performance scores and indicators has its main challenge in the data elaboration, which depends on the specific context and to the detailed performance to be evaluated. The main objective of this research is to investigate whether the evaluation of the patient's gait through markerless optical motion capture technology can be added to clinical evaluations scores and if it is able to provide a quantitative measure of recovery in the short postoperative period. A system has been conceived, including commercial sensors and a way to elaborate data captured according to caregivers' requirements. This allows transforming the real gait of a patient right before and/or after the surgical procedure into a set of scores of medical relevance for his/her evaluation. The technical solution developed in this research will be the base for a large acquisition and data elaboration campaign performed in collaboration with an orthopedic team of surgeons specialized in hip arthroplasty. This will also allow assessing and comparing the short run results obtained by adopting different state-of-the-art surgical approach for the hip replacement.

In the last years, the advent of innovative technologies for tracking human motions is increasing the interest of physicians and physiotherapist, who would like to introduce new instruments for a more objective assessment of the rehabilitation processes. At present, many motion tracking systems have been developed and their ease of use and low-cost may represent the key aspects for which these systems could be really adopted both in rehabilitation centers and in rehabilitation programs at home. Several research studies confirmed the importance of continuing rehabilitation programs at home with the aim to maintain patients' health condition at a suitable level for daily life activities. Physicians and physiotherapists need methods and tools, which can be simply adaptable for each type of patients' category and type of rehabilitation according to the assessed pathology. For achieving this need, the technology has to be suitable for both the patient side and medical personnel side. The most suitable technology for the patients are motion tracking devices which can be used through traditional IT, such as laptops, smartphones and tablets. Also for medical personnel the ease of use is very important, physicians would like to check the patient's rehab exercises according to their medical knowledge by exploiting daily life technology. This research work investigates on which are the best user-friendly programming tools and low-cost technology for 3D hand and finger tracking for the development of a serious game for rehabilitation exercises. The tasks are designed according to physiotherapists' recommendations, in order to be customizable for any single user. The following sections will describe the method, the tools adopted, and the application developed.

Keywords: Hand tracking , Leap motion device , Low-cost technology , Post-stroke rehabilitation , Unity

Low cost marker-less motion capture (Mocap) systems can be considered an interesting technology for the objective assessment of rehabilitation processes. In particular, this paper presents a feasibility study to introduce a Mocap system as a tool to assess shoulder rehabilitation. The movements of a shoulder are complex and challenging to be captured with a marker-less system because the skeleton avatar usually oversimplifies shoulder articulation with a single virtual joint. The designed solution integrates a low-cost Mocap system with image processing techniques and convolutional neural networks to automatically detect and measure potential compensatory movements executed during an abduction, which is one of the first post-surgery exercises for shoulder rehabilitation. First, we introduce the main steps of a reference roadmap that guided the development of the Mocap solution for rehab assessment of injured shoulder. Then, the acquisition of medical knowledge is presented as well as the new Mocap solution based on the integration of convolutional neural networks and 2D motion tracking techniques. Finally, the application which automatically evaluates abductions and makes available the measurements of the scapular elevations is described. Preliminary study and future works are also presented and discussed.

Keywords: Blender , Marker-less Motion capture system , Open source SDK , OpenPose , Shoulder rehabilitation

The rehabilitation process of patients after spinal cord injury (SCI) is usually based on subjective visual assessment by medical staff of rehabilitation centers. During the process, the medical personnel train patients to manage wheelchair and they learn how to use their sensible body parts in order to have a satisfactory life-style. Furthermore, physiotherapists and physicians have to control patients to prevent wrong postures that could cause further disorders. This paper describes how a low-cost marker-less motion capture system can be exploited to create an objective assessment procedure. Three Microsoft Kinect v2 sensors have been used to track patients using their wheelchairs along a straight path. The three sensors are arranged to optimize the acquisition. Thanks to the collaboration with the medical staff, we identified the set of parameters necessary to monitor patients' performance. An ad hoc application has been developed to provide the physicians with the right set of data easy readable to assess the patients along the rehabilitation process. The application has been tested involving twenty volunteers. Finally, results reached so far and further developments are summarized and discussed.

Keywords: Assessment of rehabilitation processes , Low-cost marker-less motion capture system , Microsoft Kinect v2 , Spinal cord injury

Biomechanical overload is a critical issue for the health of workers employed in manufacturing production systems, and so far it has been analysed by applying conventional observational methods. This research aims to introduce a procedure for quantitative biomechanical overload risk assessment in which surface electromyography integrates with a motion capture system, enhancing the use of Internet of Things (IoT) devices directly in the factory. A case study concerning an experimental session in a Fiat Chrysler Automobiles (FCA) assembly line is described in order to demonstrate how these devices, worn in actual working conditions, can be integrated to provide reliable data, despite possible influences of electromagnetic noise in the measures.

Keywords: biomechanical overload , IMU , IoT , manufacturing , risk assessment , surface electromyography

A critical point for manufacturing companies has always been the optimization of their production processes to increase the productivity and minimize the related costs, chasing an efficiency principle. Thanks to advent of Industry 4.0 (I4.0) era, some technologies, perceived as far away few years ago, now can be reached by everyone. The use of these technologies allows factories to acquire and evaluate their production data (and much more) and carry out complex analyses in short time making possible the improvement of the production processes. Aim of this paper is to propose a methodological framework in which, starting from an existing process, where workers and machines have already been assigned to each station of a production line, the use of Industrial Internet of Things (IIoT) devices, such as wearable ones, allows to carry out analyses of the performance parameters of the production lines by means of an event-based simulation. In this way it is possible to evaluate if improvements are possible by re-balancing or re-scheduling the line. A case study, regarding a manual task of a real manufacturing production line, is presented to demonstrate the applicability and the effectiveness of the described framework.

Keywords: Internet of Things , Line balancing , Methodological framework , Wearable devices

Aim. To evaluate the biomechanical effects of four different auxiliary-aligner combinations for the extrusion of a maxillary central incisor and to define the most effective design through finite element analysis (FEA). Materials and Methods. A full maxillary arch (14 teeth) was modelled by combining two different imaging techniques: cone beam computed tomography and surface-structured light scan. The appliance and auxiliary element geometries were created by exploiting computer-aided design (CAD) procedures. The reconstructed digital models were imported within the finite element solver (Ansys® 17). For the extrusion movement, the authors compared the aligner without an attachment with three auxiliary-aligner designs: a rectangular palatal attachment, a rectangular buccal attachment, and an ellipsoid buccal attachment. The resulting force-moment (MF) system delivered by the aligner to the target tooth and the tooth displacement were calculated for each scenario. Results. The maximum tooth displacement along the z-axis (0.07 mm) was obtained with the rectangular palatal attachment, while the minimum (0.02 mm) was obtained without any attachments. With the ellipsoid attachment, the highest undesired moments Mx and My were found. The rectangular palatal attachment showed the highest Fz (2.0 N) with the lowest undesired forces (Fx = 0.4 N; Fy = -0.2 N). Conclusions. FEA demonstrated that the rectangular palatal attachment can improve the effectiveness of the appliance for the extrusion of an upper central incisor.

Although the so-called Industry 4.0 trend is promoting the increasing automation of processes in the factories of the future, manual activities still play an extremely important role within the factory and human factors greatly affect the process performance. However, the analysis of human-machine interaction and the prediction of human performance in industry are difficult but crucial to have an optimized design of workspaces and interfaces, reducing time and cost of implementation, and avoiding late design changes. This research adopts a multimodal human-centered approach for the analysis of human-machine interaction, and proposes a multimodal experimental set-up for the evaluation of the workers' experience to support the design of industrial workstations. The set-up combines virtual mockups, interaction with both physical and virtual objects, and monitoring sensors to track users and analyze their actions and reactions. It allows creating a multimodal environment able to deepen the interaction between humans and systems or interfaces, to support design activities. Indeed, it has been demonstrated that the analysis of the reactions of the users involved, allows to evaluate the quality of the interaction, identify the critical issues, define corrective actions, and propose guidelines for system design or redesign [1]. The paper describes the application of the proposed set-up on two industrial case studies and reports the main results. © 2019 Publicaciones Dyna Sl.

Keywords: Digital Manufacturing , Human Factors , Human-Centered Design , Industry 4.0 , Virtual Reality

Due to the recent advances in technologies for gesture recognition, midair gestures can be considered the interface of the future in a large number of applications. However, designing effective interfaces with midair gestures is not an easy task because the design is application dependent and it must fulfill many requirements at the same time. Despite the availability of general guidelines in the literature, clear and well-established procedures for the optimal design of midair gesture-based interfaces are, to date, not available and remain an open issue. The main contribution of this paper is a user-centered modular framework, which integrates existing and novel methods. It supports the designer considering multiple aspects including ergonomics, memorability, and specific user requirements tailored to the application scenario. The framework involves three design steps and a final validation step, also supported by dedicated software. We tested with success the proposed framework in an industrial case study, where technicians must easily access technical information by browsing digital manuals during maintenance operations.

Keywords: Consumed endurance (CE) , ergonomics , gesture vocabulary , midair gesture interface , user-centered elicitation approach

Technical information presentation is evolving from static contents presented on paper or via digital publishing to real-time context-aware contents displayed via virtual and augmented reality devices. We present a Context-Aware Technical Information Management system (CATIM), that dynamically manages (1) what information as well as (2) how information is presented in an augmented reality interface. CATIM acquires context data about activity, operator, and environment, and then based on these data, proposes a dynamic augmented reality output tailored to the current context. The system was successfully implemented and preliminarily evaluated in a case study regarding the maintenance of a hydraulic valve.

Keywords: Aware information , Context , Industrial augmented reality , Technical information manager

The paper describes the design of an innovative virtual reality (VR) system, based on a combination of an olfactory display and a visual display, to be used for investigating the directionality of the sense of olfaction. In particular, the design of an experimental setup to understand and determine to what extent the sense of olfaction is directional and whether there is prevalence of the sense of vision over the one of smell when determining the direction of an odor, is described. The experimental setup is based on low-cost VR technologies. In particular, the system is based on a custom directional olfactory display (OD), a head mounted display (HMD) to deliver both visual and olfactory cues, and an input device to register subjects' answers. The paper reports the design of the olfactory interface as well as its integration with the overall system.

Smart environment is a key challenge for current ICT research: it is one of the solutions that can enhance people's quality of life and enable users with impairment to live independently. Over the years, scientific research has proposed several solutions to help and improve the capabilities of its occupants, but they are often developed for a specific context (e.g. particular disease or impairment). These systems do not adapt to the real needs of users with different profiles, and neglect that the user's requirements may evolve over time. This research work aims to develop a new adaptive smart system able to support users (with and without disabilities) in performing daily tasks by recognizing their preferences and actions and adapting the system feedback consequently. With the aim to develop an easy, efficient and usable adaptive smart system, the final users have been involved in the whole design and development process. The system was validated through a virtual reality system allowing the user interaction evaluation and helping the usability improvement.

Keywords: Adaptive and adaptable user interface , Bayesian network , ICT , Smart environment , User-centered design , Virtual reality system

Magika is an interactive Multisensory Environment that enables new forms of playful interventions for children, especially those with Special Education Needs. Designed in cooperation with more than 30 specialists at local care centers and primary schools, Magika integrates digital worlds projected on the wall and the floor with a gamut of "smart" physical objects (toys, ambient lights, materials, and various connected appliances) to enable tactile, auditory, visual, and olfactory stimuli. The room is connected with an interface for educators that enables them to: control the level of stimuli and their progression; define and share a countless number of game-based learning activities; customize such activities to the evolving needs of each child. This paper describes Magika and discusses its potential benefits for play, education and inclusion.

Keywords: Children , Education , Inclusion , Multisensory Environments , Play , Special Education Needs

Littering is a highly diffused anti-environmental and anti-social behavior, especially among young people. Furthermore, cigarette butts are one of the most littered items and are responsible for both severe environmental damages and high clean up expenses. The aim of this project is to design an interactive ashtray for the campus environment to limit the cigarette butts littering behavior in an engaging and effective way. Qualitative and quantitative data are collected. Coded observations were implemented through the research process, including the 2 pre (without the prototype) and 2 pros (with the prototype) sessions. Also, user experience test and one to one interview were conducted for deepening the understanding of the littering phenomenon and the reasons behind in the behavior among young people. The prototype indeed reduced the number of cigarette butts littering among observed behaviors of 156 students, especially in male sample. Final results indicate the behavior change of disposers is moderated by other factors, as the environmental cleanliness. Future development is also discussed.

Keywords: Design for Behavior Change , Gamification , Multisensory product experience , Sustainability , User centred design