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

Simulating human-robot collaboration for improving ergonomics and productivity in an assembly workstation: a case study

Objective: To simulate the interaction human-robot regarding productivity, physical and mental workload, involving the worker in the process of implementing a new Human-Robot Collaboration (HRC) system. Background: The guidelines for designing ergonomic and management of work systems are key to ensure worker safety, health, and wellbeing. It considers physical and mental workloads, including worker in the process of implementation. Method: Consists of comparing two workstations regarding physical demand, mental demand, and productivity with a sample size of 6 subjects. First workstation is a replica of a current situation, in which it is intended to implement an industrial HRC system. Second workstation is a human-robot simulated scenario, in which a human hand simulates the tasks being performed by a robot arm. Results: Robot-simulated scenario resulted in: 24.3% increase in productivity; posture exposure time reduced from 33.5% to 22.0%; overall workload felt by workers decreased from 44/100 to 38/100; and participatory ergonomics provided meaningful insights for better understanding the whole system. Conclusion: Robot-simulated improved ergonomic conditions and productivity compared to the replica-workstation and it is important to involve the worker in the implementation of a HRC system. Application: Assembly task workstations considering the inclusion of an industrial collaborative robot to perform tasks and lighten the burden on humans.This work is supported by: European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) Project n∘ 39479; and Funding Reference: POCI-01-0247-FEDER-39479; and by FCT - Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

Assessment of work-related musculoskeletal disorders by observational methods in repetitive tasks - a systematic review

Repetitive movements play an important role in the growing and aggravation of the discomforts related to the musculoskeletal system. There are many different observational methods for risk assessment for repeated movements in literature. The main objective of this review is to identify the observational methods that have been used to assess repetitive movements risk in previous studies. A systematic literature review was performed using the PRISMA protocol, in journal databases such as Taylor & Francis, Science Direct, and Scopus. We retrieved 322 articles and, after classification, 45 of them were selected for full analysis. Results showed that the most applied method was the OCRA method, especially by researchers from Italy and Brazil. Besides this, RULA (Rapid Upper Limb Assessment), QEC (Quick Exposure Check), and REBA (Rapid Entire Body Assessment) were also methods well-known and extensively applied to assess ergonomic repetitive working tasks.This work is supported by: European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project no 39479; Funding Reference: POCI-01-0247-FEDER-39479] and by FCT—Fundação para a Ciência e Tecnologia within the RR&D Units Project Scope: UIDB/00319/2020