Spatial Augmented Reality (sAR) as an assistive technology is a promising tool for experienced and novice industrial workers. Five industrial case studies in Dutch manufacturing companies are described to study the effects of sAR assistance on task completion time, learning speed, product quality, work load, technology acceptance and employability in manual assembly guidance and training. Although case study outcomes were rather positive and user acceptance was high, 2 out of 5 use case companies decided not to invest in this technology after the initial pilot project. The main barriers for implementation were concerns about the relatively high system costs, the initial instruction programming time and the required expertise to do so. Future system developments should improve the system's usability from a business process engineering perspective and thereby support zero programming of sAR systems and adaptive work instructions.

Augmented Reality (AR) as an assistive technology is a promising tool for novice operators to learn assembly processes. This experiment compared an AR instruction method to display based electronic working instructions (EWI) for product assembly, to assess learning during the first repetitions of the products. In addition, two types of work instructions were used, i.e., standard and chunk instructions. In this experiment a chunk instruction consists of six assembly steps. Effects of the instruction method and type on the learning phase were evaluated with 24 novice operators building two products i.e.. Operators were then asked to build the same products without instructions in order to assess learned skills and establish effects on the recall phase, also as a result of instruction method and type. Task completion time (TCT), product quality, operator workload and learning curve were measured. The learning curve, as indicated by the TCT, took place during the first three repetitions of product assembly. Instruction method and instruction type had no effect on the learning curve. Product quality was high and no differences were found between learning conditions. Operator workload revealed that chunking of the instruction increased workload during the learning phase. During the recall phase, the AR group's TCT increased 19.2%, but only for the first product's repetition without instruction. Product quality remained the same during the recall phase, however operator workload was reduced for chunk learned products. This study indicates that chunking of instructions should be avoided for novice workers. Both EWI and AR can be used for teaching new assembly procedures. While AR and EWI are useful during the learning phase, there are indications that these methods might hinder the operator once they required the necessary skills and knowledge to assemble the product. A possible solution is making instructions more adaptive to fit the skill proficiency of the operator.

The aim of this study was to evaluate the effect of an industrial exoskeleton on muscle activity, perceived musculoskeletal effort, measured and perceived contact pressure at the trunk, thighs and shoulders, and subjective usability for simple sagittal plane lifting and lowering conditions. Twelve male participants lifted and lowered a box of 7.5 kg and 15 kg, respectively, from mid-shin height to waist height, five times, both with and without the exoskeleton. The device significantly reduced muscle activity of the Erector Spinae (12%-15%) and Biceps Femoris (5%). Ratings of perceived musculoskeletal effort in the trunk region were significantly less with the device (9.5%-11.4%). The measured contact pressure was highest on the trunk (91.7 kPa-93.8 kPa) and least on shoulders (47.6 kPa-51.7 kPa), whereas pressure was perceived highest on the thighs (35-44% of Max LPP). Six of the users rated the device usability as acceptable. The exoskeleton reduced musculoskeletal loading on the lower back and assisted with hip extensor torque during lifting and lowering. Contact pressures fell below the Pain Pressure Threshold. Perceived pressure was not exceptionally high, but sufficiently high to cause discomfort if used for long durations.

The aim of this study was to evaluate the effect of a passive upper body exoskeleton on muscle activity, perceived musculoskeletal effort, local perceived pressure and subjective usability for a static overhead task. Eight participants (4 male, 4 female) held a load (0 kg and 2 kg) three times overhead for a duration of 30 s each, both with and without the exoskeleton. Muscle activity was significantly reduced for the Biceps Brachii (49%) and Medial Deltoid (62%) by the device for the 2 kg load. Perceived effort of the arms was significantly lower with the device for the 2 kg load (41%). The device did not have a significant effect on trunk or leg muscle activity (for the 2 kg load) or perceived effort. Local perceived pressure was rated below 2 (low pressure levels) for all contact areas assessed. Half of the participants rated the device usability as acceptable. The exoskeleton reduced muscle activity and perceived effort by the arms, and had no significant negative effect on the trunk and lower body with regards to muscle activity, perceived effort and localised discomfort.

Process models are schematic representations of business processes and support analysis for process redesign. A process model may be enhanced with additional information to further improve its analytical value (e.g. costs, throughput times, etc.). To support analysis of human factors in manufacturing processes, this paper introduces a new extension that visualizes human physical risks (such as heavy lifting or repetitive work). An existing human risk analysis method is integrated with the activity elements of BPMN. This integration facilitates a process wide risk analysis of occupational risk factors. Based on this graphical representation, users can see where in the process workers may encounter physical risks that should be mitigated through process redesign. This paper reports on the systematic design of a conceptual solution which is implemented in MS Visio and then applied and evaluated in practice.

OCCUPATIONAL APPLICATIONS In repetitive work, more physical variation is believed to reduce the risk of eventually developing musculoskeletal disorders. We investigated the extent to which workstation designs leading to more variation in upper arm postures during a pick-and-place task influenced outcomes of relevance to musculoskeletal disorder risk, including muscle activity, cardiovascular response, and perceived exertion, measured through the maximal acceptable work pace. Posture variation to the extent obtained in our experiment had only minor effects on these outcomes, and considerably less impact than a moderate change in working height. Apparently, substantial manipulations of the workstation or of the work task will be needed to accomplish variation to an extent that can significantly change outcomes of relevance to occupational musculoskeletal disorders and, thus, represent a potential for reduction in musculoskeletal disorder risk. TECHNICAL ABSTRACT Background: Repetitive light assembly work is associated with an increased risk for developing work-related musculoskeletal disorders. More exposure variation, for instance by redesigning the workstation, has been proposed as an effective intervention. Purpose: We investigated the effect of upper arm posture variation in a 1-hour repetitive pick-and-place task on shoulder muscle activity, heart rate, and perceived exertion, measured on the Borg CR-10 scale and in terms of maximal acceptable work pace (MAWP). Methods: Thirteen healthy participants performed the task in three workstation designs where the hand was moved either horizontally (H30/30), diagonally (D20/40), or vertically (V10/50), with a mean upper arm elevation of similar to 30 degrees. In a fourth design, the hand was moved horizontally at similar to 50 degrees mean arm elevation (H50/50). Results: As intended, upper arm posture variation, measured by the upper arm elevation standard deviation and range of motion, differed between H30/30, D20/40, and V10/50. However, MAWP (10.7 cycles.min(-1) on average across conditions; determined using a psychophysical approach), mean upper trapezius activity (54% reference voluntary exertion [RVE]), and heart rate (69 bpm) did not differ between these workstation designs. In H50/50, MAWP was lower (9.3 cycles.min(-1)), while trapezius activity (78% RVE) and perceived exertion (Borg CR- to the extent achieved in the current experiment leads to less effects on muscle activity and perceived exertion than a moderate change in working height.

Economically and environmentally it might be more responsible or even feasible to combine products and services to elongate product lifetime. Gispen, a major office furniture producer in the Netherlands, has embraced circular economic principles to create new business, extend product life time and improve the adaptability of their products. In the Use-it-Wisely (UIW) project two applications were developed. To estimate possible business impacts of adapting a circular economy concept for a company, a dynamic business model simulation has been created by using the system dynamics methodology. And second, Gispen has developed a new Circular Economy Design Framework to support circular product design development. A combination of basic principles to design, upgrade, and reuse products according to circular economy principles are included in the framework as well as a circular life cycle assessment methodology. The development process, non-confidential company results of the tool application and directions for future research are described in this chapter.

In this paper, we describe an experimental study that investigated the effects of electronic work instructions and AR based instructions (projected work instructions) on productivity, product quality and human operator workload. In a simulated assembly task, projected instructions on the work spot and operator guidance picking the correct component lead to significantly higher productivity and quality rates compared to instructions presented on a screen. Remarkably, at these higher levels of performance, the work load on the operator was not increased, but instead significantly decreased.

The manufacturing industry needs to adapt their product-services to meet customer requirements in today’s rapidly changing markets. This paper presents how technologies can support knowledge sharing and collaboration during product-service processes. This work was part of the European Union Use-it-Wisely project and summaries demonstration results from the project. Six cluster cases from different industry sectors (energy, machinery, space, office workplace, vehicles, and shipbuilding) were developing their tools and processes during the project. Based on the demonstration evaluations, it seems that the Use-it-Wisely project has enabled companies to improve their product-services by using interactive collaborative environments and new business models. Participants that took part in the demonstrations felt that the new approach makes users’ work easier, provides competitive advantage, facilitates knowledge sharing and decision making, extends the efficient lifecycle of existing machinery and supports sustainable development.

Objectives This study investigated the extent to which controlled changes in work pace in a cyclic pick-and-place task influence upper extremity kinematics and muscle activity, and whether an effect depends on working height. Methods Thirteen participants performed the task for 4 min at each of five work paces ranging from 8 to 12 cycles·min-1 in each of two experimental conditions where the hand was moved horizontally with an average upper arm elevation of 30° and 50°, respectively. For each work cycle, we calculated the average and standard deviation of the upper arm elevation angle and the activity of the trapezius and deltoid muscles, as well as the angular peak velocity. We summarized these seven variables by calculating averages across cycles and cycle-to-cycle variabilities. Results At 30° arm elevation, pace significantly influenced within-cycle angle variation, cycle-to-cycle variability of the average angle, angular peak velocity, and cycle-to-cycle variability of peak velocity. However, only angular peak velocity increased monotonically across all paces from 8 to 12 cycles·min-1). Average activity in the trapezius and the deltoid were the only muscle activity variables to increase consistently with pace. These effects of work pace did not change with working height. Conclusion The present study did not find any consistent work pace effect on upper extremity kinematics and muscle activity, in spite of a comprehensive empirical basis compared to previous literature. While our results suggest that work pace may not be of critical concern in an occupational health context, we encourage further studies verifying or disproving this notion.

Occupational postures are considered to be an important group of risk factors for musculoskeletal pain. However, the exposure-outcome association is not clear yet. Therefore, we aimed to determine the exposure-outcome association of working postures and musculoskeletal symptoms. Also, we aimed to establish exposure limits for working postures. In a prospective cohort study among 789 workers, intensity, frequency and duration of postures were assessed at baseline using observations. Musculoskeletal pain was assessed cross-sectionally and longitudinally and associations of postures and pain were addressed using logistic regression analyses. Cut-off points were estimated based on ROC-curve analyses. Associations were found for kneeling/crouching and low-back pain, neck flexion and rotation and neck pain, trunk flexion and low-back pain, and arm elevation and neck and shoulder pain. The results provide insight into exposure-outcome relations between working postures and musculoskeletal symptoms as well as evidence-based working posture exposure limits that can be used in future guidelines and risk assessment tools. Practitioner Summary: Our study gives insight into exposure-outcome associations of working postures and musculoskeletal symptoms (kneeling/crouching and low-back pain, neck flexion/rotation and neck pain, trunk flexion and low-back pain, and arm elevation and neck and shoulder pain). Results furthermore deliver evidence-based postural exposure limits that can be used in guidelines and risk assessments.

Aim. It is generally agreed that work postures can lead to musculoskeletal disorders in the neck and shoulders. We investigated the extent to which more variation of upper arm postures in a repetit ...

Background. It is generally agreed that constrained postures during assembly work can lead to musculoskeletal disorders in the neck and shoulders. In a controlled experiment, we investigated the extent to which more variation of upper arm postures in a one-hour repetitive task influences maximal acceptable work pace (MAWP), perceived exertion (RPE), kinematics and muscle activity.Methods. 13 participants (6 females, 7 males; age 26 (SD 3) years) performed a pick-and-place task for one hour, using their dominant hand to movie pins between two targets. We compared three conditions in which the hand was moved: (1) horizontally, at an intended upper arm elevation of 30°; (2) obliquely, at an upper arm elevation between 20° and 40°; and (3) vertically, at an upper arm elevation between 10° and 50°. Using a psychophysical approach — with imposed work paces changing every two minutes (7-13 cycles/min) — we arrived at the MAWP of each participant. Postures of the arm, trunk and shoulder were recorded throughout, as was the activity of selected muscles (not reported here). Participants reported their RPE (Borg CR-10) at baseline and at MAWP.Results. The kinematics data confirmed that the conditions had similar average upper arm elevations (32.3° (SD 1.0°) but differed in variation (arm elevation SD: 5.2°, 8.1°, 10.9°). Increased posture variation did not lead to changes in MAWP (10.7, 10.6, 10.8 cycles/min), though it did lead to slightly lower RPE values (average increase from baseline: 5.4, 4.8, 4.7).Discussion.Increased biomechanical variation has been suggested to reduce the risk of developing musculoskeletal disorders. Even though our data suggest that there may be a trend towards a positive effect of variation on work perception, the increase in posture variation imposed here was not sufficient to influence performance. Further analyses of arm, shoulder and trunk kinematics and muscle activity patterns may reveal biomechani-cal differences of interest between the protocols.

Shoulder disorders comprise a large part of work-related musculoskeletal disorders. Risk factors, such as repetitiveness and monotony, may cause muscle fatigue and be attenuated by task rotation. We investigated rotation between a dynamic box-lifting task and a relatively static pick-and-place task and aimed to determine whether (1) a high rotation frequency leads to less fatigue development than a low rotation frequency, and (2) a self-selected rotation frequency leads to less fatigue development than imposed rotation frequencies. Ten participants performed four one-hour rotation schedules: two low frequency rotation schedules rotating at 30min, one high frequency rotation schedule rotating every sixth minute, and a self-selected rotation schedule. Borg, SOFI and electromyography of Trapezius and Deltoid subparts served as fatigue indicators. We found significant signs of fatigue for most schedules regarding the Borg and SOFI ratings and the M. Trapezius pars Descendens. Task rotation frequency had no significant effect on any of the outcome parameters, whereas the self-selected rotation schedule clearly resulted in less development of perceived fatigue than imposed schedules. In conclusion, we think that freedom of rotation has the greatest potential to attenuate potential development of musculoskeletal disorders and we require due caution with the use and interpretation of EMG indicators of fatigue.

Exoskeletons may form a new strategy to reduce the risk of developing low back pain in stressful jobs. In the present study we examined the potential of a so-called passive exoskeleton on muscle activity, discomfort and endurance time in prolonged forward-bended working postures.Eighteen subjects performed two tasks: a simulated assembly task with the trunk in a forward-bended position and static holding of the same trunk position without further activity. We measured the electromyography for muscles in the back, abdomen and legs. We also measured the perceived local discomfort. In the static holding task we determined the endurance, defined as the time that people could continue without passing a specified discomfort threshold.In the assembly task we found lower muscle activity (by 35-38%) and lower discomfort in the low back when wearing the exoskeleton. Additionally, the hip extensor activity was reduced. The exoskeleton led to more discomfort in the chest region. In the task of static holding, we observed that exoskeleton use led to an increase in endurance time from 3.2 to 9.7 min, on average.The results illustrate the good potential of this passive exoskeleton to reduce the internal muscle forces and (reactive) spinal forces in the lumbar region. However, the adoption of an over-extended knee position might be, among others, one of the concerns when using the exoskeleton. (C) 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Een derde van de Nederlandse werknemers voert met regelmaat herhalende bewegingen uit in het werk. Wanneer zorgt dit voor een risico op gezondheidsklachten? Bedrijven konden dat al zelf nagaan met de Hand-Arm Risicobeoordelingsmethode (HARM). Deze methode is nu verbeterd: HARM 2.0. Vakmedia