Abstract: This paper describes the design and preliminary testing of a soft exoskeleton for the shoulder which supports the adbuction/adduction movements. The soft exoskeleton is based on a single soft bellow actuator, a pneumatically actuated system which is composed by multiple consecutive chambers that expands when compressed air is inflated till providing a desired motion. In this work we present the design, analysis, prototyping and testing of the soft bellow actuator as well as its preliminary integration into a first version of bellow-based soft exoskeleton for the shoulder.

Keywords: Soft actuators | Soft exoskeletons | Soft robotics

Abstract: Nowadays, to counteract the sedentary behavior in children, playground parks with their pieces of playground equipment can have a significant impact. In this context, the paper proposes a methodology based on wearable surface electromyography and inertial sensors data to derive functional data sheets for each piece of playground equipment and two novel synthetic indices for the assessment of physical fitness and motor coordination. These indices are built from: (i) muscle activation of nine forearm and leg muscles; (ii) acceleration data from two inertial sensors located on the forearm and lower back. The synthetic indices are based on the assessment of the muscular force rate and motor control in terms of smoothness. The validation of the proposed methodology is carried out through field tests, on seven pieces of playground equipment. The results confirm that: (i) the functional data sheet offers the possibility to obtain quick and intuitive visualization of the pieces of playground equipment in terms of required muscle activation; (ii) the proposed methodology represents a reliable and valuable tool to estimate physical fitness and motor coordination. This approach can be implemented in different playground parks even to guide the choice of the equipment to ensure specific levels of physical fitness and motor coordination.

Keywords: motor coordination | physical fitness | playground equipment | wearable sensors

Abstract: Evaluations of injuries and the assessment of residual dexterity is carried out by clinicians by means of standardized tests. Several dexterity tests have been developed and all of them require the test administrator to sit in front of the subject and visually assess the motions performed. Automatic tools can reduce the time needed for the evaluation and can provide additional useful information. For many of the available dexterity tests, automated evaluation methods have been developed. However, for the Minnesota dexterity test, despite being widely used, just one automated solution based on multiple depth sensor cameras was developed. This study aims to provide a wearable and flexible method to automatically evaluate the outcomes of Minnesota dexterity tests. The proposed methodology consists of a parametric model that is capable of processing acceleration data collected with an IMU attached to the centre of mass of the subject’s dominant hand. The developed model was successfully validated against a subject study with ten participants.

Keywords: Automatic assessment | Biomechanics | Manual dexterity | Parametric model | Wearable devices

Abstract: In this paper a methodology for the optimization of design parameters of silicone–based pneumatic soft actuators is presented. The objective is to provide a useful tool in the early design phases of soft grippers made of silicone pneumatic actuators, which are particularly suitable for the manipulation of agrifood products. The methodology presented can be used for the optimal selection of geometric parameters and/or materials to be used for the realization of the actuators, by minimizing the material used while maximizing the tip force exerted by the actuators. This force should guarantee the stable grasp without causing damage on the objects.

Keywords: fiber–reinforced soft actuators | optimization design parameters | pneumatic soft actuators | Soft robotics gripper | sustainability

Abstract: This paper describes a design method based on muscle synergies to minimize the number of sensors on surface electromyography (sEMG) shorts for monitoring motor and fun activities with playground equipment. We started from data collected during an experimental campaign with four playground equipment in Kinder Joy of Moving parks. In details, five sEMG located on the leg and one IMU located on the back were employed. From this data, muscle synergies extraction using non-negative matrix factorization algorithm was carried out. Then, the minimum number of sEMG sensors that allows the reconstruction of all sEMG patterns with a VAF for each muscle and each playground over 0.90 was defined. The results underlined how with two sEMG sensors placed on the vastus lateralis and semitendinosus, is possible to reconstruct five sEMG patterns for all four-playground equipment guaranteeing an accuracy in terms of VAF cumulative over 0.97. This work might pave the way to simplify the design of sEMG shorts for motor and fun activities reducing invasiveness, costs and environmental impact.

Keywords: design methods | muscle synergies | playground activity | surface electromyography | wearable sensors

Abstract: In engineering design, the selection of the optimal design solution represents a critical phase for the development of successful products. In this paper, we present ELIGERE, an open source decision support system targeted at engineering design applications. It allows to rank multiple design solutions with respect to different evaluation criteria according to the evaluations provided by a group of experts. ELIGERE is composed by three main modules: (1) a distributed web application, for generation and participation to the decision making session; (2) a mathematical engine, based on the fuzzy analytical hierarchy process, to quantify the results of the decision making session according to the evaluation of the experts; (3) a relational database, to collect and store data. The most important contribution of this paper is introducing a practical and effective software tool that facilitates decision-making analysis based on the fuzzy analytical hierarchy process, thereby allowing better-informed choices on concept selection, as it has been designed with a specific focus on the engineering field. In this paper we describe the key concepts of ELIGERE and its modalities of use in several real use cases. Finally, we compare ELIGERE with the widely used general purpose decision support software based on the fuzzy analytical hierarchy process.

Keywords: Concept selection | Decision support systems | Engineering design | System evaluation

Abstract: In this work, the design and the experimental characterization of a soft gripper which takes inspiration from the octopus tentacle is presented. The system is a single silicone-based pneumatic soft actuator which is able to perform bending motion thanks to its particular geometry and, due to the presence of an embedded suction cup, it can provide enhanced adhesion to the object surface of the goods to be grasped. Firstly, the design aspects as well as the fabrication process of the single-tentacle soft gripper are described. Then, its performances in terms of bending behavior, static deflection, shape variation under applied load and detachment force of the suction cup are evaluated. The experiments include grasping tests of spherical payloads with different weights. This gripper might have impact in the grasping and manipulation of delicate products like mozzarella in the agrifood field.

Keywords: soft grippers | soft robotics | tentacle gripper

Abstract: In this paper, two concepts of silicone–based pneumatic soft bending actuators with stiffening capability are presented and compared in terms of performances and sustainability. The first concept is a PneuNet bending actuator with a vacuum chamber, while the second one is a Fiber–reinforced bending actuator, again with a vacuum chamber. Both soft actuators are able to perform a bending movement and are able to increase their stiffness through layer jamming. The two concepts are first compared in terms of overall performances, namely bending behavior, capability to exert tip forces and stiffening capability. After, they are compared in terms of sustainability, through the analysis of the energy that they require for movement execution.

Keywords: performances | pneumatic soft actuators | Soft robotics | stiffening | sustainability

Abstract: This paper describes a robust design approach to optimize the design of smart shorts for muscle activity analysis. A practical application related to electromyographic shorts for monitoring six main thigh muscles is shown. Starting from a 2D digital model of a pattern block related to the shorts, a robust design approach is applied to optimize the design of textile electrodes for surface electromyography analysis in terms of size (i.e., diameter), and location (i.e., inter-electrode distance). The aim is to reduce the sensitiveness to noise factors (i.e., skin lubrication condition, anthropometric variability and gesture type) guaranteeing the best performance in terms of Signal Noise Ratio. The experimental campaign related to football activities allows the practical application of the proposed approach for the design of smart shorts for football. The results allow to define the optimal configurations for the six muscles of interest. This work might pave the way for the development of tailored smart garments for electromyography analysis.

Keywords: electromyographic system | human body scanning | robust design | wearable sensors

Abstract: Soft robots are increasingly advancing into heterogeneous contexts, however they still suffer from different sustainability issues including limited lifetime, disposal and poor energy efficiency. These issues severely limit their spread usage thus leading to the need for new materials and efficient actuation systems. The main goal of this work is to find out in scientific literature the main indicators concerning environmental sustainability in pneumatically actuated soft robots. To reach this goal, we used the PRISMA methodology to explore, in a systematic manner, available indices related to environmental dimension of sustainability. The indicators found are reported with the absolute and relative metrics adapted from the references and two proposed categorizations: i) one related to the part of soft robotic system, ii) the other one related to the LCA-oriented Product Lifecycle (PL) phase. The study highlights the lack in the literature of indicators related to energy consumption regarding environmental dimension of the manufacturing process, thus opening the possibility of future studies in this direction.

Keywords: Pneumatic actuation | Soft Robotics | Sustainability

Abstract: Functional evaluation plays an important role in determining suitable training programs for elite athletes. For athletes with Intellectual Impairment, it may represent an even more powerful tool as it allows to obtain quantitative feedbacks (when qualitative ones are hard to collect). This study presents practical examples in the context of strength assessment tests carried out in the functional evaluation project of the Italian Sport Federation for athletes with Intellectual Impairment (FISDIR). In particular, a useful customized tool for the assessment of explosive strength in sprinters, based on biomechanical indices, is presented. The proposed approach starts with the definition of key biomechanical parameters in terms of spatiotemporal, kinematic, kinetics, energetic and joint angles related to each main phase of the test. According to the literature and technical recommendations, reference target values for each parameter are defined and normalized. In addition, a quick graphical visualization was designed. Finally, two synthetic indices related to the performance and execution are developed. Practical implications in squat jump test are presented. The proposed methodology represents a useful customized tool for improving training in athletes with Intellectual Impairment.

Keywords: biomechanics | Functional evaluation | intellectual impairment | strength assessment

Abstract: Artificial limbs can help people missing body parts to restore some of their daily-life activities. However, the user should spend up to a few months to intuitively control the new device. During this period, she/he may suffer pain due to wearing or using the prosthesis inappropriately. This research presents a virtual simulator that allows the user to carry out training sessions for controlling the prosthesis. A set of Surface Electromyographic (sEMG) sensors are used to acquire the signals from user's muscles and send them to a recognition algorithm that interprets the patient's intentions. Simultaneously, the patient observes the response of her/his device on the simulator. Two studies are presented: the first study evaluate the performance of three different recognition algorithms i.e., Linear Discriminant Analysis (LDA), Support Vector Machine (SVM), and Multi-Layer Perceptron (MLP), based on the successful recognition of the patient's intentions. The second study investigates the least number of sEMG sensors to be used, as having less components improves the patient's wearability and decreases the processing time. The developed simulator represents a real prosthetic device, PRISMA hand II. The results showed the superiority of the MLP with 80% of successful recognition when 6-sEMG sensors are used. If a reduced set of gestures is considered (frequently needed by the patient), 90% of successful recognition could be achieved. Less sEMG sensors significantly degraded the performance of the recognition algorithm as only 53.8% of successful recognition could be achieved. All experiments were conducted with the help of a patient with below-elbow amputation.

Keywords: Active prosthetic hand | Biomechatronic application | Multi-Layer Perceptron (MLP) | Pattern recognition | Rehabilitation robotics | sEMG signal processing

Abstract: This paper presents the use of surface electromyographic (sEMG) signals for the actuation of soft pneumatic artificial muscles. The idea behind this paper is finding a relationship between a natural muscle and an artificial muscle, do it through an analysis of the sEMG data. We start from the characterization of a specific soft pneumatic artificial muscle and we relate the root mean square value of the sEMG signal to the contraction of the actuator itself. This work might pave the way for the development of intuitive wearable interfaces for the actuation of soft robots.

Keywords: Human biosignal | Soft actuators | Surface electromyographic sensors | Wearable technologies

Abstract: This paper describes the design of a novel fabric–based antagonistic pneumatic actuator with multiple chambers that can be used for the development of soft continuum manipulators for collaborative tasks. The concept consists of three pneumatic chambers of fabric material capable of being actuated independently. By connecting multiple actuators of this kind, it is possible to obtain soft continuum manipulators capable of complex movements and able to change the stiffness of their elements. In this work we highlight the design and prototyping of the soft actuator and we present the preliminary experiments in terms of motion and stiffening capabilities.

Keywords: Fabric pneumatic artificial muscles | Soft actuators | Soft continuum manipulators | Soft robotics

Abstract: The paper focuses on a preliminary study of an easy-to-customize capacitive soft sensor to measure forces that can enable soft robot features like sensitive skins or permits dexterous object manipulation thanks to the perception of the grasping force. The prototype has been realized overlapping five different layers choose among commercial and easy to find materials. The sensor is completely composed by customized or self-produced parts. The stack definition involves compatibility test to define the correct combination of layers and adhesives. An evaluation of the behavior has been performed applying weights in the range [20–5800] g finding a mean sensitivity of 0.143 pF/kg over an initial value C0 of 3.151 pF. The sensor prototype showed good performance in term of sensitivity and hysteresis in the defined application range. Dielectric viscoelastic phenomena and decreasing repeatability have been observed in the upper part of the measuring range. The sensor proposed shows promising characteristics encouraging future developments.

Keywords: Capacitive force sensor | Conductive inks | Customizable force sensor

Abstract: In this paper we present the preliminary evaluation of an active soft bellow exoskeleton for assistance during overhead tasks. The evaluation was performed using objective (i.e., joint angles and muscle activations) and subjective (i.e., Borg Cr R-10 and System Usability Scale - SUS scales) measurements. The subject, involved in the experimental campaign, performed in laboratory conditions a drilling overhead task typical of the automotive industry, once using the exoskeleton and once without the exoskeleton. The preliminary results underlined the positive effect of the exoskeleton in terms of physical effort and usability.

Keywords: biomechanics | overhead tasks | soft exoskeletons | usability

Abstract: Design methods for sports engineering allow to improve the world around the athlete. In cycling, a sport device that can be useful to reduce and monitor the risk of injuries is a smart glove equipped with pressure sensors. The literature underlined how the current design methods lack the comprehensive consideration of sensors integration for force analysis at the handlebar. Furthermore, the majority of existing solutions is based on resistive pressure sensors. In this work, we present mainly two advancements with respect to the state-of-the-art: (1) user-centered design methodology for the glove development, which allows to take care about the main design parameters which involve the cyclist, namely her/his anthropometric characteristics and her/his sport gesture analysis (achieved by the pressure analysis on the handlebar) during classic grip position of cycling (i.e., top grip); (2) prototyping of custom-made capacitive pressure sensors instead of classic commercial resistive pressure sensors. The work involves the concept generation, the selection of the optimal concept through Kano and Quality of Function Development as well as the preliminary prototyping of one capacitive pressure sensor, realized using a fabrication process involving additive manufacturing techniques and silicon molding.

Keywords: capacitive sensors | human body scanning | injury risk | user-centered design

Abstract: This paper proposes a systematic approach for involving the clinicians in the design of medical devices, here used for the development of a soft robotic glove for rehabilitation. The approach considers the integration of different methodologies that take into account the emotional information of the clinicians considered as end–users (i.e. Kano–Kansei) and a deep analysis of the needs of both the patients and the clinicians (i.e. house of quality). Based on this user–centered approach, the paper develops different rehabilitation concepts realized through the technique referred to as design of experiments. Finally the optimal one is chosen re–involving the clinicians and using the ANOVA analysis.

Keywords: Hand rehabilitation | Product development | Soft robotics | User-centred design

Abstract: Objective and reliable assessment of motor functions, such as dexterity, is a key point for evaluating worker’s abilities. In this context, the proposed work presents a tool for objective automatic assessment of the Minnesota Dexterity Test using cameras with depth sensors. Typical performance measurements (i.e., total time and associated percentiles) were estimated using custom algorithms. In addition, the possibility to identify the qualifiers for the code d440 of the International Classification of Functioning, Disability and Health was implemented in the developed algorithms. The proposed tool can also identify the mistakes most frequently committed by the subjects. To prove the capabilities of the proposed method, a series of experimental trials was conducted with 10 healthy young volunteers. Results showed that the developed tool helps clinicians to obtain performance feedback and evaluate patients’ dexterity quickly without bias.

Keywords: Automatic assessment | Biomechanics | Depth cameras | Manual dexterity | Motion capture

Abstract: Helping workers return to work as soon as safe and functionally possible after a workplace injury is a subject of major interest in the context of occupational health. For this, we developed a serious game for construction industry aimed at training workers about the proper use of an electric pallet truck inside a simulated environment. The simulation platform is endowed with a physical control interface and three training missions were implemented. During the game experience, the player is also asked to answer to some questions about the possible risks and the related protection measures. The results of preliminary experiments about the usability of our training framework are here reported and discussed.

Keywords: learning | product interface design | serious games | usability assessment | virtual training

Abstract: In this paper, we present a biomechanical analysis of the upper body, which includes upper-limb, neck and trunk, during the execution of overhead industrial tasks. The analysis is based on multiple performance metrics obtained from a biomechanical analysis of the worker during the execution of a specific task, i.e. an overhead drilling task, performed at different working heights. The analysis enables a full description of human movement and internal load state during the execution of the task, thought the evaluation of joint angles, joint torques and muscle activations. A digital human model is used to simulate and replicate the worker’s task in a virtual environment. The experiments were conduced in laboratory setting, where four subjects, with different anthropometric characteristics, have performed 48 drilling tasks in two different working heights defined as low configuration and middle configuration. The results of analysis have impact on providing the best configuration of the worker within the industrial workplace and/or providing guidelines for developing assistance devices which can reduce the physical overloading acting on the worker’s body.

Keywords: Biomechanics | Digital human models | Electromyography | Ergonomics | Industry | Overhead tasks

Abstract: This work proposes a novel virtual reality system which makes use of wearable sensors for testing and validation of cooperative workplaces from the ergonomic point of view. The main objective is to show, in real time, the ergonomic evaluation based on a muscular activity analysis within the immersive virtual environment. The system comprises the following key elements: a robotic simulator for modeling the robot and the working environment; virtual reality devices for human immersion and interaction within the simulated environment; five surface electromyographic sensors; and one uniaxial accelerometer for measuring the human ergonomic status. The methodology comprises the following steps: firstly, the virtual environment is constructed with an associated immersive tutorial for the worker; secondly, an ergonomic toolbox is developed for muscular analysis. This analysis involves multiple ergonomic outputs: root mean square for each muscle, a global electromyographic score, and a synthetic index. They are all visualized in the immersive environment during the execution of the task. To test this methodology, experimental trials are conducted on a real use case in a human–robot cooperative workplace typical of the automotive industry. The results showed that the methodology can effectively be applied in the analysis of human–robot interaction, to endow the workers with self–awareness with respect to their physical conditions.

Keywords: Cooperative workplace | Ergonomic analysis | Human– robot physical interaction | Virtual reality | Wearable sensors

Abstract: Applications as robotic harvesting or pick and place in the agrifood domain require robotic grippers able to gently manipulate delicate products, while guaranteeing high gripping power and adhesion forces on smooth surfaces. Existing soft grippers are mainly based on pneumatic bending actuators which can guarantee a gentle manipulation, but they suffer from low gripping power and possibility of slip of the manipulated object. This paper describes a novel design concept of soft robotic pneumatic gripper with embedded suckers. The concept consists of four soft fingers, each one comprising an elastomeric structure with two separate air paths, one for pressurizing the finger for generating bending motion, one for vacuum–based adhesion to the object’s surface via suction pads distributed along the surface of the finger. In this work we highlight the concept design of the mechanical system and the pneumatic control unit.

Keywords: Bioinspired design | Concept design | Soft grippers | Soft robotics

Abstract: The presented work shows how a user centered approach might be used to generate and select the optimal design of smart garments for biosignal acquisition. Design is driven by human biosignal analysis, allowing the translation of subjective user’s feelings into technical specification and the definition of customized criteria for concepts evaluation. So, different concepts are generated and, involving users again, the optimal one is chosen using multi criteria decision making based on Fuzzy AHP theory. A case study on a wearable system (i.e., electromyographic shorts) for football performance and risk injury analysis is shown.

Keywords: Biological knowledge in engineering science | User centered design | Wearable technologies

Abstract: In this study we propose a brief analysis of recent soft wearable robots for upper–limb which could have a major impact on future developments and applications. The systems are analysed with respect to: design concepts, actuation systems, sensing systems, control strategies and applications. Finally, a discussion and open issues are presented.

Keywords: Exoskeletons | Soft robotics | Wearable robotics

Abstract: In this work we derive the requirements of a soft upper-limb exoskeletons starting from the biomechanical analysis of human workers while performing three different industrial overhead tasks in laboratory settings. The results of the work allow to define the degrees of freedom which need to be supported to reduce the biomechanical overloads, as well the dimensional characteristics, in terms of required lengths and forces, of the soft actuators of the wearable robot.

Keywords: Biomechanics | Design | Industrial tasks | Soft exoskeleton | Soft robotics | Wearable robotics

Abstract: The use of fast and accurate scanning systems for human worker digitization might pave the way towards the development of multiple best practices to be implemented in industry, for enhancing safety and wellness of workers. In this work, an advanced measurement system for human body 3D reconstruction is used for extracting anthropometric characteristics of a worker, which are then used for estimation of joint torques in a simulated lifting task.

Keywords: 3D body measurements | 3D body scanner | Digital human modeling | Industrial ergonomics

Abstract: In this paper, we propose a user-centered approach for the design of ergonomic workplaces. The method is based on the evaluation of subjective opinions and objective measures from the worker, while performing the industrial tasks. The ergonomic design of industrial workplaces will have impact in reducing the musculoskeletal disorders of workers.

Keywords: Adaptable workplace | Human-oriented design | Industry 4.0 | Worker ergonomics

Abstract: Nowadays, technology in sport plays an important role to help training and judgement processes. This study proposes the use of a wearable inertial system to derive novel biomechanical indices for the assessment of performance and infringements in race-walking. These indices are built from five inertial-based parameters: loss of ground contact time, loss of ground contact step classification, step length ratio, step cadence and smoothness. The biomechanical indices are customized for elite race-walkers, and represented on a radar chart for an intuitive analysis of performance and infringements. From the radar chart, a synthetic index regarding the athlete’s overall gesture is derived. The validation of the biomechanical indices is carried out in field tests, involving nine elite race-walkers wearing an inertial sensor located at the end of the column vertebra (L5–S1). A statistical analysis is used to determinate the quality and reliability of the proposed indices and of their representation. The results show that these biomechanical indices can be implemented on a wearable inertial system for assistance in training and judgement in race-walking.

Keywords: Biomechanics | Field tests | Graphical data analysis | Infringements | Performance | Race-walking | Wearable sensors

Abstract: After the global spread of a severe acute respiratory syndrome caused by a coronavirus (SARS-CoV-2), factors that influence viral diffusion have gained great attention. Human-to-human transmission mainly occurs through droplets, but viral RNA clearance in different biological fluids in coronavirus disease 2019 (COVID-19) remains unclear. We aimed to correlate the presence and the relevant temporal patterns of SARS-CoV-2 viral RNA in biological specimens (stool, urine, blood, and tears) of the transmission with clinical/epidemiological features in patients with COVID-19. We focused on the time window between the positivity of reverse transcriptase-polymerase chain reaction (RT-PCR) tests from different specimens. We used the Mantel–Cox log rank test to verify the differences in terms of viral shedding duration, while we employed the Mann–Whitney U-test for subgroup analysis. This review protocol was registered with PROSPERO number: CRD42020183629. We identified 147 studies; we included 55 (1,348 patients) for epidemiological analysis, of which we included 37 (364 patients) for statistical analysis. The most frequently used specimens other than respiratory tract swabs were stool samples (or anal/rectal swabs), with a positivity rate of 48.8%, followed by urine samples, with a positivity rate of 16.4%; blood samples showed a positivity rate of 17.5%. We found that fecal positivity duration (median 19 days) was significantly (p < 0.001) longer than respiratory tract positivity (median 14 days). Limited data are available about the other specimens. In conclusion, medical and social communities must pay close attention to negativization criteria for COVID-19, because patients could have longer alternative viral shedding.

Keywords: COVID-19 | post-acute phase | SARS-CoV-2 | stool | viral shedding

Abstract: In this paper we present novel biomechanical indices for site-specific assessment of injury risk in cycling. The indices are built from a multifactorial analysis based on the kinematics and kinetics of the cyclist from the biomechanical side, and muscle excitations and muscle synergies from the neurophysiological side. The indices are specifics for three body regions (back, knee, ankle) which are strongly affected by overuse injuries in cycling. We use these indices for injury risks analysis of a recreational cyclist, who offered to participate in the experiments. The preliminary results are promising towards the use of such indices for planning and/or evaluating training schedule with the final goal of reducing non-traumatic injuries in cycling.

Keywords: biomechanics | cycling | electromyography | injury risk | laboratory test

Abstract: A fast and objective evaluation of kinematic characteristics of an elite athlete's gesture is necessary for refining her/his performance. When the athlete has a reduced capacity and/or reliability of expression, as in the case of subjects with intellectual impairment, objective performance analyses are even more important. In this work, we present a preliminary study regarding performance analysis on sprint tests performed by elite athletes with intellectual impairment, wearing an inertial sensor at the bottom end of their vertebral column. In particular, we compare three different inertial-based algorithms for automatic detection of temporal events, in steady-state velocity phase, with respect to the benchmark values obtained through video analysis.

Keywords: functional sports assessment | inertial sensors | intellectual impairment | kinematic parameters | sprint test

Abstract: Excessive values of force on L5/S1 joint can cause work-related musculoskeletal disorders, such as low back pain. Currently, the reference solution for estimating such variables is the combination of optoelectronic system and force platform, used for calculating the bottom up inverse dynamics in laboratory settings. Here we propose and validate a novel, completely wearable solution, composed by twelve inertial measurement units and pressure insole sensors. We validate the wearable solution with respect to the output of the reference solution, with data collected simultaneously on a subject performing lifting and releasing tasks with two different loads. The results are encouraging towards the use of the wearable methodology, considering the great impact of such a solution in a real manufacturing scenario.

Keywords: biomechanical loads | ergonomics | motion analysis | occupational disease | wearable system

Abstract: People with intellectual impairment show low performances in motor control, especially in complex movements. Performance analysis methods, based on wearable inertial sensor, are often used in typical developed swimmers but have never been used in swimmers with intellectual impairment, for whom the use of quantitative systems would be even more important. This paper presents a case study conducted on freestyle swimmers from the functional evaluation project of the Italian Sport Federation for athletes with Intellectual Impairment (FISDIR). The tests were conducted by five Italian elite swimmers with intellectual impairment using a structured experimental protocol which foresees an inertial sensor located on the wrist. Key freestyle temporal and kinematic parameters were assessed. A high-speed camera was used as a benchmark to validate the inertial-based parameters. The preliminary results indicate that the proposed inertial-based approach correlates over 90% with the performance indices obtained with the camera-based approach, and therefore it could represent a useful tool for monitoring and improving the training.

Keywords: intellectual impairment | performance analysis | sports biomechanics | swimming | wearable inertial sensor

Abstract: This paper presents IART, a novel inertial wearable system for automatic detection of infringements and analysis of sports performance in race walking. IART algorithms are developed from raw inertial measurements collected by a single sensor located at the bottom of the vertebral column (L5–S1). Two novel parameters are developed to estimate infringements: loss of ground contact time and loss of ground contact step classification; three classic parameters are indeed used to estimate performance: step length ratio, step cadence, and smoothness. From these parameters, five biomechanical indices customized for elite athletes are derived. The experimental protocol consists of four repetitions of a straight path of 300 m on a long-paved road, performed by nine elite athletes. Over a total of 1620 steps (54 sequences of 30 steps each), the average accuracy of correct detection of loss of ground contact events is equal to 99%, whereas the correct classification of the infringement is equal to 87% for each step sequence, with a 92% of acceptable classifications. A great emphasis is dedicated on the user-centered development of IART: an intuitive radar chart representation is indeed developed to provide practical usability and interpretation of IART indices from the athletes, coaches, and referees perspectives. The results of IART, in terms of accuracy of its indices and usability from end-users, are encouraging for its usage as tool to support athletes and coaches in training and referees in real competitions.

Keywords: Biomechanics | Inertial sensor | Judgment | Race walking | Step classification | Training improvement | User-centered design

Abstract: This paper shows how studies on the biomechanics and neuroscience of human movements might be used for the design of wearable systems customized for humans. Such design is driven by key biomechanical and neuromuscular parameters extracted from accurate measurements made on the human body motion, as well as by subjective data collected from the end-users of the products through questionnaires. We present three case studies developed at ERGOS Lab: a wearable system for sports performance analysis; a synergy-based approach for industrial wearable robots; a soft wearable robotic glove for hand rehabilitation.

Keywords: Biomechanics | Design methods | Neuromuscular activity | Wearable technology

Abstract: 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

Abstract: 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

Abstract: 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

Abstract: In this work we will show some preliminary results on the use of a wearable inertial system for assessment of performances and infringements in race-walking. The proposed system is composed by two parts, one for measurement and one for management purposes. The management unit is based on biomechanical-based parameters for evaluating performances and infringements. The preliminary experimental results are promising towards the use of this system in real field training and competition scenarios, to respectively assist coaches and judges.

Keywords: race-walking | sports biomechanics | wearable inertial sensors

Abstract: The use of fast and accurate scanning systems for human body digitization might pave the way towards the development of less invasive processes for medical manufacturing. In this work, an advanced measurement system for human body 3D reconstruction is used to design tailored assistive devices. The system is a photogrammetric 3D body scanner developed by the authors.

Keywords: 3D body measurements | assistive devices | medical manufacturing

Abstract: Introduction and Objectives Fabrication processes for spinal orthoses require accurate three-dimensional (3D) models of the patients' trunk. Current methods for 3D reconstruction used in this field mainly include laser or structured light scanning; these methods are time expensive and invasive, especially for patients with partial disabilities. Therefore, a theoretically instant system for data acquisition of anatomical structure is highly desirable. The objective of this work is to show the feasibility of using digital photogrammetry for human body digitization to generate accurate 3D models of the patients' trunk for spinal orthoses fabrication. Materials and Methods Multiple synchronized two-dimensional images of the human torso are captured from different points of view using a photogrammetric scanner. A 3D model is generated using the state-of-the-art algorithms for point cloud and surface reconstruction. The digitized model is then used as input for the standard computer-aided design (CAD)/computer-aided manufacturing (CAM) process of fabrication. R4D from Rodin4D is used as prosthetics and orthotics CAD software. A robotic cell constituted by a six-axis KUKA KR 30-3 is used for milling a polyurethane foam. Vacuum forming is then adopted to generate the orthosis. Two spinal orthoses are fabricated using this approach and a classical one; then, they are evaluated using quantitative and qualitative metrics. Results The data acquisition using this approach lasts 50 milliseconds. The 3D reconstruction accuracy averages 0.21 ± 1.27 mm, which suits for the considered health care scenario. Results of the initial fitting of the orthoses fabricated with the presented method show better performances in terms of time (44%), product quality (35%), and patient experience (30%). Conclusions Digital photogrammetry can be used to enhance the data acquisition and data processing of anatomical surfaces for the CAD/CAM process of spinal orthoses. The data acquisition time, almost instant, allows an easy compliance of many patients. The data processing allows generating accurate models of the patient's body. The overall process generates orthoses with a better quality with respect to those manufactured using conventional procedures. ©

Keywords: CAD/CAM | fabrication techniques | photogrammetry | prosthetics and orthotics | spinal orthoses | three-dimensional reconstruction

Abstract: 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

Abstract: 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

Abstract: 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

Abstract: This work explores the use of an industry-oriented digital human modelling tool for the estimation of the musculoskeletal loads corresponding to a simulated human activity. The error in using a static analysis tool for measuring articulations loads under not-static conditions is assessed with reference to an accurate dynamic model and data from real experiments. Results show that, for slow movements, static analysis tools provide good approximation of the actual loads affecting human musculoskeletal system during walking.

Keywords: Biomechanics | Dynamics | Gait analysis | Kinematics | Virtual simulation

Abstract: Aim of this study was to validate an inertial system able to detect the loss of ground contact (LOGC) in race-walking through outdoor tests in real training conditions. An inertial sensor was placed at L5/S1 of the vertebral column of a Italian national team athlete to acquire timing measurements of the LOGC. Data were encoded by a well-defined protocol. After a preliminary laboratory study, the athlete performed outdoor-field-tests at different velocities. A specific e-bike with a high-speed camera allowed to acquire a video and to validate sensor measurements. Results indicate that the inertial system can improve the accuracy in detecting the visible LOGC.

Keywords: inertial sensor | loss of contact | outdoor test | Race walking | video analysis

Abstract: This paper describes a new motion analysis protocol for race-walking. The protocol has been tested under laboratory conditions on a real athlete of the Italian national race-walking team. The experimental setup included a motion capture system and a force platform to record both kinematic and dynamic aspects of the athletic action. Thus, any infringement of the rules can be detected, based on the measure of knee flexion-extension and the loss of ground contact. The biomechanical efficiency can be determined from the joint angles and the temporal components of gait. The results of experiments show that the protocol can be a valuable tool to assist athletes and trainers in improving race-walking technique.

Keywords: Biomechanics | Dynamics | Experimental protocol | Gait Analysis | Kinematics | Motion Capturing | Race-walking