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Mean value and standard deviation of relative error related to the case study at medium frequency for both side of all combinations of TB procedure. Blue, green and red bars represent the combination in which the threshold amplitude is set to 3°, 5° and 10°, respectively. Clusters on the x-axis represent the possible time threshold value. Each bar corresponds to a specific combination among the nine tested algorithms.
Source publication
OCRA (OCcupational Repetitive Action) is currently one of the most widespread procedures for assessing biomechanical risks related to upper limb repetitive movements. Frequency factor of the technical actions represents one of the OCRA elements. Actually, the frequency factor computation is based on workcycle video analysis, which is time-consuming...
Citations
... Previously, Occupational Repetitive Action (OCRA), an ergonomic method to determine the risk to workers due to repetitive movements in their work activities, and rapid upper limb assessment (RULA), which is an [21][22][23] ergonomic evaluation method for posture adopted by the operator in the workplace for the upper limbs [24,25]. Evaluations were performed to diagnose surgeries. ...
Background:
Musculoskeletal System Disorders (MSDs) are a group of injuries that represent common occupational diseases and should be evaluated for prevention purposes because an increase has been observed due to the repetitive movements performed in the industry. This research was carried out in a manufacturing industry where metal parts are manufactured, and workers experience back and wrist pain.
Objective:
To prediagnose Musculoskeletal System Disorders (MSDs) and examine the relationship between temperature, demographic, and physiological factors in workers through predictive models, contributing to MSD prevention.
Methods:
Information from 36 operators was used to obtain vital signs and somatometry data, and thermograms of their hands in the dorsal, palmar, and back areas were collected and analyzed to determine the relationship between temperature and demographic and physiological factors.
Results:
The ergonomic evaluations proved that the operators were at high risk owing to repetitive movements and postures adopted during work. Eighty-six percent of cases with injuries were identified using infrared thermograms, proving their high level of effectiveness. When studying the relationship between temperature behavior during recovery from repetitive activities and demographic and physiological factors, it was determined that age, dominant hand, respiratory frequency, and BMI were the most significant.
Conclusions:
Nine regression models were obtained, with coefficients of determination between 0.17 and 0.71. The significant factors for worker injuries were age, dominant hand, respiratory rate, and BMI. However, the sample size and variability in work activities should be extended to generalize the findings.
... In response, an innovative method was proposed to automatically calculate dynamic technical movements based on inertial data. Nine combinations of this algorithm were tested by varying the time and amplitude thresholds (Taborri et al., 2020). The possibility of automatically calculating the OCRA frequency factor is offered, thus avoiding the time-consuming and labor-intensive aspects of video analysis. ...
... To determine the expected values of the mathematical model, we identified the reference process k under different settings. Ergonomic risk values have been categorized according to different action frequencies (Taborri et al., 2020), and in these experiments we focused on medium-high risk scenarios. The settings for each parameter are shown in Tables 1 and 2. Importantly, to maximize production efficiency within an acceptable threshold of musculoskeletal disorder risk, the post-switch processing speed ( 2 ) was set higher than the pre-switch speed ( 1 ) in our experiments. ...
The rapid development of automation technology in recent years has led to extensive research on how machines can replace human labor. However, many manufacturing companies may find the costs of smart production prohibitively high, while flexible manual production can result in higher profits. According to reports on the burden of disease in different countries, upper limb musculoskeletal disorders (UL-WMSDs) are the most prevalent occupational disease in industrialized countries, and they account for a significant portion of compensation. These disorders are often linked to the working environment, intensity, and duration of work. In this paper, the OCRA (Occupational Repetitive Action) index method is employed to assess the biomechanical risks associated with repetitive movements of the upper limb, and mathematical models were developed to automatically estimate the force, posture, and repetitive elements in this method. This paper proposes the OCRA index model for ergonomics based on the optimal switching problem when the processing time follows either an exponential or a generally distributed pattern. Finally, based on the switching model, numerical experiments were conducted in a medium-high action frequency scenario in order to evaluate the effect of speed changes on the OCRA index before and after switching. The experimental results enable us to find the optimal combination of the processing speed and the reference process k to minimize the total processing time in a safe ergonomic risk range.
... Several studies in literature used these assessment methods in order to assess ergonomic risks in assembly lines, including ergonomic workload [18,30], material handling [25,31], and awkward postures [20,25]. However, the main limitation of these approaches stems from the time-consuming nature of assessing all the relevant variables needed for the computation due to reliance on manual pen and paper procedures [24,34]. Hence, increased research efforts have been focused on managing ergonomic hazards, which can be evaluated through wearable devices (noise and vibration exposure), thereby offering more dependable measurements for the assessment of ergonomic risks [20]. ...
Productivity and concerns regarding the well-being of workers exposed to vibrations stand as significant topics within labor-intensive sectors. In particular, this study contributes to the existing research by analysing the problem with linkages among worker skill level, production rates and vibration exposure. A bi-objective mixed integer linear programming model was employed to optimize both productivity and the exposure to hand-arm vibration in the manufacturing workplace. A sensitivity analysis was carried out to examine the impact of key parameters on the trade-off between productivity and vibration exposure. The results demonstrate the model's effectiveness in determining the best job rotation schedules by achieving optimal productivity and vibration exposure for low and medium problem sizes. Moreover, the numerical case study points out that strengthening the workforce by adding more proficient skilled workers can maintain a good level of productivity with a decreased likelihood of excessive vibration exposure.
... Metode OCRA merupakan suatu metode yang bisa digunakan untuk mengidentifikasi suatu kinerja yang lebih relatif dengan menggunakan model nonprametrik yang pertama kalinya dikembangkan pada tahun 1994 oleh Parkan. OCRA iyalah metode yang begitu sederhana yang mempunyai kemampuan untuk memantau serta membandingkan suatu kinerja dengan cara sifat berulang [2], [13]- [19]. ...
In this study, a study was conducted to determine the Best Chat Application, the more we enter the digital era, the more applications and communication media or sending messages that appear. So researchers want to do research to determine which chat application is the best that people can use and unfortunately it is suitable for use today, then a system is applied that can help to decide, namely a Decision Support System (DSS) which can simplify the process of selecting the Best Chat Application by implementing 5 criteria i.e. Security, Number of Downloads, Reviews, Features, Storage. So we need a system that can make decisions by using SPK that applies the ROC and Operational Comprtitiveness Rating Analysis(OCRA) methods in getting the weighting value for each criterion and preference value from the best alternative, namely alternative A¬1 with the name Whatsapp Application with a preference value of 128,3123
... According to Taborri et al. (2020), the main drawback of OCRA is the time required to measure all considered factors to perform its calculation due to being a pen and paper-based method. They proposed a threshold-based algorithm that counts the dynamical technical actions required to obtain the actual frequency to minimize such a disadvantage. ...
... OCRA is the most suitable to assess the risk of hand injuries. Anyway, even if it takes into account a series of measurements for the repetition of specific manual gestures (e.g., Palmar, Pinch, and Hook grip), the approach is still observational [3]. On one hand this limits the precision, on the other an ergonomist may require several days for analyzing videos of the tasks in order to manually identify these gestures, measure the frequency and assess the risk [4]. ...
In manufacturing, ergonomic and productivity benefits may result from combining the sensing and dexterity of the human workers with the strength of collaborative robots (cobots). Anyway, manual tasks requiring repetitive motion or working with robots can cause musculoskeletal disorders especially of the hands. In such a context, this paper proposes a novel solution that includes both a full body inertial system and a dedicated solution for hand tracking. This allows implementing the standard methods for assessing ergonomic indexes and to introduce new advanced task analyses based on gesture evaluation. The benefits reached by the integrated system for body and hand tracking can be exploited in the virtual prototyping of collaborative workstation in the manufacturing domain. Different software packages have been considered to model and simulate the collaboration between the operator and the cobot. In particular, Unity and ROS are used to develop the virtual scene and control the cobot behavior and the HTC Vive Head Mounted Display (HMD) to interact with the virtual environment. Physical ergonomics is evaluated by using both a full body suit (XSENS) and sensorized gloves (MANUS). The solution has been applied to the simulation of a virtual production line where the operator collaborates with a six-axis cobot (NIRYO ONE). Test tasks require the operator to move and manage different objects and tools by simulating different types of grasping. Real-time feedback about ergonomics, in terms of posture evaluation and alerts in case of critical condition, is shown to the operator as well as the automatic generation of reports for the post-process evaluation of the entire process. The results show how the use of these tools can be effective in the ergonomic evaluation of a collaborative robotic workstation which requires manual tasks.
... The method involves manual observation by experienced technical specialists. The main disadvantages of OCRA include the time required to compute all considered factors, especially the counting of the technical actions to estimate the frequency factor, and intra-and intersubject assessment variability [81]. ...
Repetitive labor-intensive tasks are common in civil construction projects. Construction workers are prone to getting into musculoskeletal disorders-related injuries while performing such activities. The paper proposes a novel approach to identify the theoretical maximum attainable level of safety, safety frontier, for a given construction task that can be achieved in perfect conditions under good management. The paper outlines the method and the framework components and demonstrates them through an actual construction-lab-based case study. The case study includes computation of safety frontier for lifting and setting down tasks. For this, the paper proposes to use a depth sensor camera (Kinect) for workers' postural data collection while performing the task. With the postural data as an input feature, all the unique actions are identified using a random forest classifier model for each movement frame. Also, the paper proposes to develop a moment prediction model to predict the lower back moment exerted in each movement frame. The lower back moment is computed using inverse kinematics and inverse dynamic in OpenSim for the training data set. Then, the paper implements a random forest regression algorithm to create a moment prediction model with postural data and velocity as input features. Finally, the safe work posture, safety frontier is computed, combining the unique actions exerting minimum lower back moment. The computed safety frontier can potentially help the safety managers to improve their safety strategies by providing a higher safety benchmark for monitoring their construction site.
... The OCRA method is also one of the useful methods used to analyze workers' exposure to the risk factors of upper limb musculoskeletal disorders resulting from repetitive tasks through calculating the OCRA index or determining the risk limit values using the OCRA checklist by taking into account frequency, force, posture, additional factors, duration of each repetitive task and lack of recovery time (16)(17)(18). Various studies have been conducted using this method as a standard method for assessment of the risk of upper limb musculoskeletal disorders, including the study carried out by Tosin (2019) (19)(20)(21)(22)(23). Several studies have been conducted on the relationship between the methods for assessment of musculoskeletal disorders. ...
Background and objective:
Repetitive tasks are among the causes of musculoskeletal disorders. Assessment of repetitivetasks is performed through various methods with different scores and significance given to risk factors considered in these methods. Knowing the strengths and weaknesses of each method can contribute to modifying the methods and improving the correlation between them. This study aimed to investigate the correlation between ART and OCRA methods in a career with repetitive movements.
Methods:
After hierarchical task analysis in a vegetable grower job with repetitive movements, the subtasks were assessed by an assessor who mastered both ART and OCRA methods. The final score of each method was checked using the Pearson correlation coefficient in SPSS 18, after testing the normality of data.
Results:
Moderate risk levels were reported for 16 out of the 14 sub-tasks analyzed using both methods. In the ART method, 3 sub-tasks and in the OCRA method, 2 sub-tasks had high-risk levels. The Pearson correlation coefficient was 0.842 indicating a moderate correlation between the two posture assessment methods.
Conclusion:
The findings of the study showed an acceptable correlation and compatibility between the two methods considering the risk levels.
... In order to incorporate this type of analysis to the systems under study, the Check List OCRA (occupational repetitive action) method has been selected. This method considers the complete work cycle, including periods of activity, recovery and breaks [41]. It also incorporates a postural analysis, focused mainly on the upper limbs, although in a less exhaustive way than the RULA and REBA methods. ...
The Renaissance treatise De Re Metallica (Georgius Agricola, 1556) is one of the first works that deals in detail with the state of the art of metal mining, compiling the main techniques and mechanical devices used in this industrial activity at that time. An advanced knowledge of the human–machine set is observed in this treatise, from a mechanical and ergonomics point of view. The main objective of this work is to carry out an ergonomics analysis of one of the mechanical devices collected in the sixth book of this treatise. It is intended to show that there was a certain concern for ergonomics in the Renaissance, long before the first appearance of this concept. Specifically, a mine water extraction pump, powered by three different systems, is analyzed. Current ergonomics assessment methods have been used to perform this comparative analysis. The postural load has been assessed by the rapid upper limb assessment (RULA) and the rapid entire body assessment (REBA). The Check List OCRA (occupational repetitive action) has been used to perform the analysis of repetitive movements. The results have shown an evolution of the machine, not only on a mechanical level, but also in movements, postures, and safety of the operator for the three methods applied. It is, therefore, an example of practical and real ergonomics applied to machine design dating from the 16th century. In addition, this work may be a very interesting tool for teaching, since it allows showing examples of ergonomics in productive areas related to historical context.
... Taborri et al. [40] proposed one novel IMU-based algorithm for counting technical actions toward determining the OCRA frequency factor for risk assessment. Their approach used a time and amplitude threshold, counting the first minimum/maximum pair in a signal which meets these thresholds as a technical action. ...
