Tarefas de manipulação manual de cargas : selecção de métodos de avaliação de risco

Dissertação de mestrado em Engenharia HumanaA Manipulação Manual de Cargas está presente num conjunto significativo de tarefas que uma extensa multiplicidade de operadores tem de realizar nos seus postos de trabalho, ocorrendo transversalmente, desde a indústria transformadora, à construção, passando pelos serviços. Contudo, esta manipulação manual constitui um determinante factor de risco para o desenvolvimento de Lesões Músculo-Esqueléticas relacionadas com o Trabalho. Este risco pode ser minimizado através de uma intervenção ergonómica baseada na identificação e na avaliação dos factores de risco associados a esse tipo de tarefas. Para tal, existem diversos métodos que permitem identificar e avaliar o risco de lesões músculo-esqueléticas na manipulação manual de cargas. Pretendeu-se com este estudo elaborar um Guião, que permita, de forma simples, apoiar a selecção e de aplicação do método mais apropriado para avaliar esse risco num posto de trabalho específico. Da análise bibliográfica realizada foram analisados vários métodos distintos, sendo que 10 deles foram incluídos no Guião. A fase seguinte envolveu a realização de um questionário de contextualização do presente estudo. Um dos principais resultados que foi possível inferir do questionário indica que grande parte dos técnicos conhece, por vezes com detalhe, alguns dos métodos mas, em simultâneo, desconhecem a forma de aplicação dos mesmos, ou sentem alguma dificuldade em seleccionar o método mais apropriado. Tendo em consideração este resultado, foi desenvolvida uma ferramenta informática cujo objectivo consiste em apresentar de forma intuitiva o Guião desenvolvido e permita que a selecção do método de avaliação do risco seja feita de forma apropriada. Depois, a partir de uma amostra de possíveis utilizadores finais deste produto, testou-se a sua usabilidade, com a administração de um inquérito por questionário, de modo a avaliar: (1) a eficácia, estimada pela taxa de sucesso dos utilizadores mediante uma tarefa pré-definida; (2) a eficiência, medindo o tempo dispendido para atingir os objectivos; e (3) o grau de satisfação dos utilizadores, relativamente à empatia, aprendizagem, controlo, ajuda e eficiência do Guião. Os dados obtidos, apontam para uma avaliação global positiva da aplicação informática. O facto de o Guião não permitir realizar os cálculos directamente relativos à aplicação dos métodos foi o aspecto negativo mais apontado pelos utilizadores. Relativamente aos aspectos positivos mais referenciados, estes estão relacionados com a facilidade de consulta do Guião, com o seu aspecto gráfico, bem como com o facto de este produto constituir um meio de informação sobre os métodos considerados. Espera-se que este trabalho permita uma maior difusão dos métodos seleccionados e que a sua escolha seja facilitada, permitindo também minimizar os riscos inerentes às tarefas de Manipulação Manual de Cargas.Manual Handling of Loads is present in a significantly group of tasks that a wide variety of workers has to realize in their workplaces, occurring transversally, from the transforming industry, to the construction industry, passing through services. However, this manual handling constitutes a determinant risk factor for development of work-related musculoskeletal disorders. This risk can be minimized through an ergonomic intervention based on the identification and evaluation of risk factors associated with this type of tasks. For that purpose, there are several methods for identifying and evaluating the risk for musculoskeletal disorders in the manual handling loads. With this study it was intended to develop a simple Guide, with a simple structure, in order to be used as a decision-making support for the selection and application of the most appropriate method to assess this risk at a particular workplace. The undertaken literature review has analyzed several different methods, being 10 of them included in the Guide. The next stage involved the realization of a questionnaire of contextualization of the present study. One of the main results that could be obtained from the questionnaire indicated that most of the practitioners know, sometimes in detail, some of the methods but, simultaneously, they do not know how to implement them or, at least, feel some difficulty in selecting the most appropriate method. Taking this result into account, it was developed a multimedia tool whose purpose was to provide an intuitive way to the developed Guide and to allow that the methods selection for risk assessment is done properly. Afterward, using a sample of possible final users of this product, its usability was tested, using the administration of a questionnaire, in order to evaluate: (1) the efficacy, estimated by the success rate of users by means of a pre-defined task; (2) the efficiency, measuring the needed time to achieve the goals; and (3) the degree of satisfaction of the users, relatively to empathy, learning, control, helpfulness and efficiency of the Guide. The obtained data, points to a global positive evaluation of the multimedia tool. The fact that the Guide does not allow to carry out the calculations directly relative to the application of the methods was the negative aspect more frequently pointed by the users. Concerning the more evidenced positive aspects, these are related with the facility in consulting the Guide, with its graphic appearance, as well as the fact that this product constitutes a mean of information about the considered methods. It is expected that this work will permit a wider dissemination of the selected methods and that its choice becomes easier, also allowing minimizing the risks inherent to the manual handling tasks

Obesity influence on perceived physical overload during vertical handling loads - A preliminary study

Obesity prevalence is increasing among the Portuguese workforce, similarly to other industrial countries. Obesity seems to negatively affect the individuals’ work capacity. Tasks with vertical handling loads, including lifting and lowering, are very common in occupational contexts. With the aim of studying the possible effect of obesity on workers’ physical overload during vertical handling loads, psychophysical data were collected from a total of 14 participants with different obesity levels (non-obese, high level of obesity and very high level). The participants were asked to go through 6 lifting trials with different occupational conditions and, for each task tested, they reported physical loading by using the Borg’ “Category Ratio-10” (CR-10) scale. The obtained results in this preliminary study are not conclusive about the obesity influence on perceived physical overload during vertical handling loads. Accordingly, this study should be continued, by considering a statistically valid sample and other psychophysical techniques that can complement the CR10 scale results

Estudio y análisis de un nuevo dispositivo para la rehabilitación de la articulación tibiotarsal

Introduction: Currently, there are several types of devices and techniques for the rehabilitation of the tibiotarsal joint. However, complete and effective rehabilitation still falls short of expectations, since the existing devices are not adaptable to the level of torque and the number of repetitions and sessions to be performed, as these depend on each patient and on the stage at which he is finds. Objetives: To improve a mechatronic device for the rehabilitation of the tibiotarsal joint, the Therapheet. Methods: This study presents a review of the tibiotarsal joint rehabilitation protocols, as well as the classification of devices used for this purpose. Thus, the purpose is to improve the Therapheet, developed at the Department of Mechanical Engineering of the University of Minho, obtaining a viable, functional and safe rehabilitation device, standing out from the rest on the market, since it allows the execution of the six rehabilitation exercises. Results: It was obtained a prototype of equipment for rehabilitation of the tibiotarsal joint was obtained, proposing changes for improvement according to the specificities and requirements for such a device, having been subjected to a series of preliminary tests to verify its functionality, performance and suitability. The equipment proved to be functional, in terms of executing the ankle rehabilitation movements, however, it still manifests some flaws in terms of the user's stability, sudden movements, and above all dysfunctions arising from excess mass that make up its structure and limitations pneumatic technology adopted. Conclusions: The control of the amplitude of the characteristic angles of the movements of the foot is still done manually, so it would be significant to implement an automated system that would allow the control of the range of amplitude, according to the patient's rehabilitation phase. One option would be the implementation of a new technology, such as the insertion of servomotors.Introdução: Atualmente existem vários tipos de dispositivos e técnicas para a reabilitação da articulação tibiotársica. No entanto, a reabilitação completa e eficaz ainda está aquém das expectativas, uma vez que os dispositivos existentes não são adaptáveis ao nível do binário e do número de repetições e sessões a executar, pois estas dependem de cada paciente e do estádio em que este se encontra. Objetivos: Melhorar um dispositivo mecatrónico, de reabilitação da articulação tibiotársica, o Therapheet. Métodos: Neste estudo é apresentada uma revisão dos protocolos de reabilitação da articulação tibiotársica, assim como a classificação dos dispositivos utilizados para este propósito. Assim, a finalidade é aperfeiçoar o Therapheet, desenvolvido no Departamento de Engenharia Mecânica da Universidade do Minho, obtendo-se um dispositivo de reabilitação viável, funcional e seguro, destacando-se dos restantes no mercado, uma vez que permite a executação dos seis exercícios de reabilitação. Resultados: Foi obtido um protótipo de equipamento para reabilitação da articulação tibiotársica, propondo alterações de melhoria de acordo com as especificidades e os requisitos necessários para um dispositivo deste tipo, tendo sido submetido a uma série de testes preliminares para verificar a sua funcionalidade, desempenho e adequabilidade. O equipamento demonstrou ser funcional, a nível de execução dos movimentos de reabilitação do tornozelo, no entanto, ainda manifesta algumas falhas ao nível da estabilidade do utilizador, movimentos bruscos, e sobretudo disfunções provenientes de excesso de massa que compõe a sua estrutura e de limitações da tecnologia pneumática adotada. Conclusões: O controlo da amplitude dos ângulos característicos dos movimentos do pé ainda é feito manualmente, pelo que seria significativa a implementação de um sistema automatizado que possibilitasse o controlo da graduação da amplitude, de acordo com a fase de reabilitação do paciente. Uma opção seria a implementação de uma nova tecnologia, como a inserção de servomotores.Introducción: Actualmente, existen varios tipos de dispositivos y técnicas para la rehabilitación de la articulación tibiotarsal. Sin embargo, la rehabilitación completa y efectiva aún no cumple con las expectativas, ya que los dispositivos existentes no son adaptables al nivel de torque y al número de repeticiones y sesiones a realizar, ya que dependen de cada paciente y la etapa en la que se encuentra. Objetivos: Mejorar un dispositivo mecatrónico para la rehabilitación de la articulación tibiotarsal, el Therapheet. Métodos: Este estudio presenta una revisión de los protocolos de rehabilitación de la articulación tibiotarsal, así como la clasificación de los dispositivos utilizados para este propósito. Por lo tanto, el propósito es mejorar un dispositivo mecatrónico desarrollado en el Departamento de Ingeniería Mecánica de la Universidad de Minho, el Therapheet, obteniendo un dispositivo de rehabilitación viable, funcional y seguro, que se destaque del resto en el mercado, ya que permite la ejecución de los seis ejercicios de rehabilitación. Resultados: Se obtuvo un prototipo de equipo para la rehabilitación de la articulación tibiotarsal, proponiendo cambios para mejorar de acuerdo con las especificidades y requisitos de dicho dispositivo, habiendo sido sometido a un serie de pruebas preliminares para verificar su funcionalidad, rendimiento e idoneidad. El equipo demostró ser funcional, en términos de ejecución de los movimientos de rehabilitación de tobillo, sin embargo, todavía presenta algunos defectos en términos de estabilidad del usuario, movimientos bruscos y, sobre todo, disfunciones derivadas del exceso de masa que conforman su estructura y limitaciones. Tecnología neumática adoptada. Conclusións: El control de la amplitud de los ángulos característicos de los movimientos del pie todavía se realiza manualmente, por lo que sería importante implementar un sistema automatizado que permita el control del rango de amplitud, de acuerdo con la fase de rehabilitación del paciente. Una opción sería la implementación de una nueva tecnología, como la inserción de servomotores.This work has been supported by FCT – Fundação para a Ciência e Tecnologia with-in the R&D Units Project Scope: UIDP/04077/2020. It has been also supported by FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

Ergonomics and human factors as a requirement to implement safer collaborative robotic workstations: a literature review

There is a worldwide interest in implementing collaborative robots (Cobots) to reduce work-related Musculoskeletal Disorders (WMSD) risk. While prior work in this field has recognized the importance of considering Ergonomics & Human Factors (E&HF) in the design phase, most works tend to highlight workstations’ improvements due to Human-Robot Collaboration (HRC). Based on a literature review, the current study summarises studies where E&HF was considered a requirement rather than an output. In this article, the authors are interested in understanding the existing studies focused on Cobots’ implementation with ergonomic requirements, and the methods applied to design safer collaborative workstations. This review was performed in four prominent publications databases: Scopus, Web of Science, Pubmed, and Google Scholar, searching for the keywords ‘Collaborative robots’ or ‘Cobots’ or ‘HRC’ and ‘Ergonomics’ or ‘Human factors’. Based on the inclusion criterion, 20 articles were reviewed, and the main conclusions of each are provided. Additionally, the focus was given to the segmentation between studies considering E&HF during the design phase of HRC systems and studies applying E&HF in real-time on HRC systems. The results demonstrate the novelty of this topic, especially of the real-time applications of ergonomics as a requirement. Globally, the results of the reviewed studies showed the potential of E&HF requirements integrated into HRC systems as a relevant input for reducing WMSD risk.This work has been supported by FCT–Fundação para a Ciência e Tecnologia and MIT Portugal Program under the doctoral Grant SFRH/BD/151365/2021. This work has been also supported by NORTE-06-3559-FSE-000018, integrated in the invitation NORTE-59-2018-41, aiming the Hiring of Highly Qualified Human Resources, co-financed by the Regional Operational Programme of the North 2020, thematic area of Competitiveness and Employment, through the European Social Fund. Additionally, has been also supported by FCT within the Project “I-CATER–Intelligent robotic Coworker Assistant for industrial Tasks with an Ergonomics Rationale”, Ref. PTDC/EEIROB/3488/2021, and within R&D Units Project Scope: UIDB/00319/2020

Safety requirements for the design of collaborative robotic workstations in europe – a review

Industrial manufacturing is moving towards flexible and intelligent processes. Human-Robot Collaboration (HRC) has a pivotal role in smart factories due to a more versatile resource allocation that ultimately drives higher productivity and efficiency. The physical barriers that separate robots’ and humans’ workspaces are removed to facilitate HRC, which raises new safety concerns. To cope with this new robotics paradigm, regulatory legislation and international safety standards have been issued and are enforced for any machinery placed in factories. In this paper, we aim to shorten the gap between research projects and industry-ready robotic systems, by providing the guidelines and general requirements for collaborative robotic applications. We review the current international safety standards, certification procedures under the scope of European jurisdiction, and elaborate a literature review of papers related to safety for collaborative workstations.This work was supported by NORTE-06-3559-FSE-000018, integrated into the invitation NORTE-59-2018-41, aiming to hire highly-qualified human resources, co-financed by the Regional Operational Programme of the North 2020, thematic area of Competitiveness and Employment, through the European Social Fund (ESF)

Ambiente térmico no setor dos transportes de mercadorias - o caso de um veículo sem ar condicionado

The thermal environment in the workplace is decisive in creating the optimal conditions and maximizing the productivity of the workers. The value of the different environmental variables such as temperature, radiant heat, relative humidity and individual variables (such as metabolism and clothing) are determinants to evaluate the thermal stress exposure of workers during their daily activity. The objective of the current study is to evaluate the occupational exposure to the thermal environment of a heavy goods vehicle driver, motivated by frequent complaints, such as the difficulty of sleeping in the vehicle with high temperatures during the day. To determine the conditions to which the driver is exposed, the globe temperature, dry and wet bulb temperatures, as well as the air velocity inside the vehicle were measured, considering both the work and the rest situation. In addition, the metabolism related to physical activity and the thermal insulation conferred by clothing were also determined. Once the parameters were obtained, Professor Malchaire's Excel (R) sheet was used for obtaining the values for the Wet Bulb Globe Temperature (WBGT) index, which were above the occupational exposure limit values (ISO 7243). Results point to a hot work environment where thermal stress is liable for the dissatisfaction of workers. The need to act on thermal stress is imperative, preferably through the implementation of engineering and organizational protection measures that can improve the workplace. The need to establishment of a legislation set to address this particular issue was also an outcome of this work

Decision-making framework for implementing safer human-robot collaboration workstations: system dynamics modeling

Human-Robot Collaboration (HRC) systems are often implemented seeking for reducing risk of Work-related Musculoskeletal Disorders (WMSD) development and increasing productivity. The challenge is to successfully implement an industrial HRC to manage those factors, considering that non-linear behaviors of complex systems can produce counterintuitive effects. Therefore, the aim of this study was to design a decision-making framework considering the key ergonomic methods and using a computational model for simulations. It considered the main systemic influences when implementing a collaborative robot (cobot) into a production system and simulated scenarios of productivity and WMSD risk. In order to verify whether the computational model for simulating scenarios would be useful in the framework, a case study in a manual assembly workstation was conducted. The results show that both cycle time and WMSD risk depend on the Level of Collaboration (LoC). The proposed framework helps deciding which cobot to implement in a context of industrial assembly process. System dynamics were used to understand the actual behavior of all factors and to predict scenarios. Finally, the framework presented a clear roadmap for the future development of an industrial HRC system, drastically reducing risk management in decision-making.This work was supported by European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project n◦ 39479; Funding Reference: POCI-01-0247-FEDER-39479] and by FCT - Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/202

Implications of obesity on occupational health

Obesity is an emerging public health problem. Therefore, obese subjects are a growing fraction of the workforce. Although different negative effects of obesity on work performance have been demonstrated before, additional studies are required to provide a more complete understanding of those effects on work performance. This study aimed to analyse the perceptions of occupational health practitioners about the obesi-ty implications on some work tasks, especially on manual materials handling tasks. With this purpose, qualita-tive data were collected from eight semi-structured interviews. The interviewees argued that obese workers present different limitations, such as lower physical resistance, locomotor difficulties and postural restrictions. These individual limitations have negative implications on work, namely on absenteeism and on the decrease of productivity. To prevent these consequences, companies should adopt educational programs, among other initiatives, in order to establish a culture of health promotion at the workplaces.Universidade do Minho. Escola de Engenhari

Revised Strain Index – RSI (Garg, Moore, & Kapellusch, 2017)

Texto de apoio.[Excerto] Introdução: Em postos de trabalho com um predomínio de trabalho manual e de esforços repetitivos, os trabalhadores estão continuamente expostos ao risco de desenvolvimento de Lesões Musculoesqueléticas Relacionadas com o Trabalho (LMERT) das Extremidades Distais dos membros Superiores (EDS). Estas lesões podem afetar os cotovelos, antebraços, punhos e mãos, sendo frequentemente reportadas em trabalhadores de escritório (com uso contínuo de computador), como noutros contextos ocupacionais onde se verifique uma contínua realização de tarefas manuais repetitivas (Garg & Kapellusch, 2011). A síndrome do túnel cárpico é a LMERT-EDS mais comum em contextos industriais de manufatura (Garg et al., 2012), sendo o Revised Strain Index (RSI) um método focado na previsão de ocorrência de lesões em músculos e tendões do punho (especialmente para a referida síndrome) (Roman-Liu, 2014). É de destacar que os autores do método salientam que este foi desenhado para determinar o risco de LMERT-EDS associado a um dado posto de trabalho, e não para avaliar pessoas (Garg et al., 2017). Para além de fatores organizacionais, ambientais e pessoais, os principais fatores de risco que levam ao desenvolvimento deste tipo de lesões são: força manual, frequência de movimentos, posturas incorretas, duração da tarefa com movimentos repetitivos. Na literatura científica existem vários métodos observacionais que permitem avaliar quantitativamente o risco de ocorrência destas lesões, incluindo o RSI que considera os fatores anteriormente mencionados. Este método, considerando a sua versão original, é recomendado pela ISO 11228-3:2007 para a uma avaliação analítica do risco de LMERT-EDS (Antonucci, 2019). Recentemente, Garg et al. (2017) apresentaram o RSI como uma versão revista do Strain Index (SI), inicialmente proposto por Moore & Garg (1995). [...

Manual materials handling: knowledge and practices among Portuguese health and safety practitioners

Manual Materials Handling (MMH) has been considered one of the major problems in occupational settings and, accordingly indicated as one of the main reasons for musculoskeletal diseases in a wide variety of workplaces. To ascertain the associated risk, several methodologies need to be identified and/or the risk involved in the MMH task evaluated. The aim of this work was to characterize the knowledge and use of risk assessment methods amongst Portuguese Health and Safety (H&S) practitioners. Methodologically, this study consisted in the application of an online survey whose completion was requested by e-mail to all Portuguese H&S practitioners, as well as to other related prevention professionals. The previously developed and validated questionnaire included three different sections. The first section regarded the company’s characterization. The second section, intended to characterize the situation of the company concerning the MMH tasks while the third section included the characterization of the respondent use and knowledge about risk assessment methods for MMH tasks. The answers obtained were collected amongst almost 350 companies. The characterization of the companies showed that there is a predominance of H&S external services for Small and Medium-sized Enterprises and that for large companies the adoption of internal services was the most adopted structure. In what regards the most used and recognized methods, the largest percentage of answers were given to the NIOSH equation, the Key Indicator Method (KIM) and Manual Assessment Chart (MAC) method. Questionnaire results show that a significant part of the H&S practitioners recognise some methods but have difficulty applying them correctly. Finally, some practitioners reported that they had never used any type of risk assessment methods.Autoridade para as Condições do Trabalho (ACT