Work Posture Simulation Using Catia VSR20 at Virgin Coconut Oil Production

. This study aims to measure the posture of a worker by analyzing the level of occupational health risk and the level of fatigue of the physical load in a posture with a high level of posture risk and proposes to improve posture to reduce the risk of musculoskeletal disorders. RULA is a method used to evaluate work posture, CATIA V5R20 software is used to simulate workers while doing work, and heart rate are the data used to identify the level of physical workload. The results of the work posture analysis show that the workers at station coconut husk stripping have the highest level of risk with a RULA score of 7 (red), which means that the work is very tiring and at risk of experiencing MSDs and needs to improve immediately. Based on the analysis of the classification of physical workloads, it shows that 76% of the coconut husk stripping work activity is a heavy and tiring workload category for the work. The proposed posture improvement shows a decrease in score.


Introduction
Ergonomic principles must be considered in designing a workstation to increase productivity and reduce health and safety risks.One focus of ergonomics is body posture.Work posture affects work results; postures that are not by ergonomic rules will cause fatigue and are at risk for MSDs.[1] [2] Many ergonomic methods and techniques can be used to evaluate the workplace, such as the Rapid Upper Limb Assessment (RULA) method.[3] The RULA is amongst the most applied, popular and easy to use ergonomic assessment method.Many researchers have applied it in various sectors and concluded the relative risk levels in various tasks observed.RULA is usually considered as more conservative and strict method for posture evaluation.Similar to many other observational methods, it uses categorizations with the relevant problem of borderline areas.
Some studies used ergonomic assessment in the coconut oil processing industry.The pure coconut oil production process consists of 4 stages: stripping coconut husks, cutting coconut shells, shredding coconut meat, and heating coconut milk using the thermal method.The worker's posture at each workstation experienced bending posture, too high shrugging, wrist rotated repeatedly, and the hand was constantly in a non-neutral position.The working posture can be seen in Figure 1.

Fig. 1. Four Working Posture Station of Coconut Oil Production
Therefore, it is necessary to do a posture analysis at each workstation to manufacture virgin coconut oil to find out which workstation has the riskiest work posture for MSDs and requires immediate changes or repairs.[4] stated that workers experience a medium level of risk; further investigation and improvement of the working system at the coconut dregs mixing station are needed after boiling.[5] Evaluates the work posture of coconut milling operators.The result is that the work has a high and medium risk level.Based on an analysis of the job strain index, the job is included in the dangerous category.
[6] Designed a human hand graphic model using CATIA on anthropometry of 32 subjects.Human modeling using CATIA can help designers visualize handheld products and controls used.[7] conducted an analysis of energy consumption for employees when exercising, based on the classification of the physical workload in terms of heart rate [8], it was found that 76% of tennis is a heavy category for workers.This study measures posture to determine the level of risk of work posture on the health of the worker's body, to determine the level of fatigue of the physical workload in a posture that has a high level of posture risk, and proposes to improve posture to reduce the risk of musculoskeletal disorders.

Research Methods
The number of workers observed was five people.Every day they work in each part of the workstation.They must finish 60 coconuts to produce 4 liters of virgin coconut oil daily.SOLIDWORKS and CATIA V5R20 software for designing workpieces that workers use to simulate modeling the human when doing work.The Rapid Upper Limb Assessment (RULA) was used to measure the risk of MSDs.The questionnaire Nordic Body Map to find out workers' complaints during work [9].The Oximeter is used to measure heart rate while working.The Stopwatch measures the processing time of each workstation to manufacture virgin coconut oil.Anthropometry was used to measure the dimensions of the worker's body.Forty-three subjects were used for the anthropometric measurement.Figure 2 shows the anthropometric data as an input in human modeling.The working posture was modeled based on the worker's actual working posture.Furthermore, it was analyzed using the RULA method to measure the risk of MSDs. Figure 2. shows several steps in evaluating posture.

Fig.2. Anthropometric measurement in human modelling
Figure 3 shows the research design, which is divided into two parts: the stage of data collection and data analysis.The data collection stage was carried out by observing work postures, distributing questionnaires, measuring body dimensions, working heart rate, and processing time.The data analysis phase is carried out by analyzing the validity of the data, and used to make a mannequin based on anthropometric measurements in fig 2, after that modeling humans according to the working conditions of workers for posture analysis, then analyzing the level of physical workload fatigue.The formation of human modelling postures in coconut oil manufacturing was simulated using the 50th percentile to accommodate the average body size of workers.The process of traditionally making virgin coconut oil takes place in one cycle of work posture activity: stripping coconut husks, cutting coconut shells, shredding coconut meat, and heating coconut milk to produce pure oil.These activities are assessed with the RULA classification based on human modelling that resembles a worker's posture.

Coir Stripping Work Station
Working Process   Based on the results of the RULA analysis, the upper arm gets a value of 3 (yellow), meaning that this part of the body does not receive excessive muscle tension but must be considered.The forearm scores 3 (red) because it is experiencing muscle fatigue in doing work, so it requires immediate corrective action.The wrist has a value of 3 (orange) which means that the wrist experiences muscle fatigue and has the potential to cause wrist injury due to pressure from repeated movements, so changes in action are needed shortly.The neck, body, and legs have a value of 7 (red) which means the work has muscle fatigue and has the potential to experience MSDs if the work posture lasts for a long time.The final analysis of the working posture of coconut husk stripping has a value of 7 (red).Overall, this posture is very tiring and risky for workers and must be repaired immediately.Based on the results of the RULA analysis, the upper arm received a value of 1 (green) and 3 (yellow),  The position of the body of the worker who is shaving the coconut meat with the position of the hand holding and directing the coconut on the shaved knife causes muscle fatigue in the left wrist.That is because the muscles of the left wrist are flexed, so they are attracted when the wrist position presses the coconut on the drawstring knife.The following is a description of the results based on the RULA analysis output.Based on the results of the RULA analysis, the upper arm gets a value of 3 (yellow), which means that this part of the body does not receive excessive muscle tension but must be considered.The forearm scores 2 (yellow) and 1 (green), meaning this body part does not receive excessive muscle tension.The wrist has a value of 1 (green) and 3 (orange), which means that the left wrist experiences muscle fatigue when holding the wrist in a retracted position to press the coconut shell on the grated knife so that the working position needs to be considered.Overall the posture of the upper arm, forearm, and wrist for the right side of the body does not have significant muscle fatigue.However, on the contrary, the wrist on the left side of the body has muscle fatigue.It has the potential for injury due to pressure from repetitive movements, so action is needed to change.The neck, body, and legs have a value of 2 (green), meaning that the body part does not have muscle fatigue.The final result of the analysis of the working posture of shaving coconut meat has a value of 3 (yellow) which means that overall, this posture is quite tiring and needs attention.The results of the analysis using CATIA software can be seen in Figure 16.

Fig.11. RULA Analysis Workstations for Cooking Coconut Milk into Coconut Oil
The body of the worker who is heating coconut milk to become coconut oil with the position of the hand holding the spatula, stirring the coconut milk, and standing for ± 1 hour causes muscle fatigue in the lower arm and right wrist.This is because the muscles of the forearm and right wrist experience repeated flexion and twists.The following describes the results based on the RULA analysis output.Based on the results of the RULA analysis, the upper arm received a value of 1 and 2 (green), which means that this part of the body does not receive muscle tension.The forearm scores 2 (yellow), meaning this body part does not receive excessive muscle tension.The wrist has a value of 1 (green) and 2 (yellow), meaning that the right wrist experiences muscle fatigue when stirring the coconut milk, so the working position must be considered.Overall, the posture of the upper arms, forearms, and wrists for the right and left sides of the body did not have significant muscle fatigue.The neck, body, and legs have a value of 3 (yellow), meaning that the body part has muscle fatigue needs to be considered.The final result of the work posture analysis for heating coconut milk into coconut oil has a value of 3 (yellow) which means that overall, this posture is quite tiring and needs attention.

Heart Rate Measurement While Working
From the ergonomics viewpoint, every workload a person receives must be appropriate or balanced in terms of physical, cognitive, and human limitations who receive the load.Assessment of workload levels is carried out at workstations that have the highest risk of work posture.The risk value is obtained from the final results of posture analysis at each workstation.From the analysis results, the workstation with the highest risk is the coconut husk stripping workstation, so it is necessary to measure heart rate to determine the level of physical workload fatigue experienced by workers at the workstation.Measurements were carried out using a stopwatch and an oximeter in each work cycle to complete the stripping of 30 coconuts.The following is the heart rate measurement data in Table 5.Based on the heart rate data from the table above, the frequency of data using SPSS using the easy category is coded (1) if the heart rate is 90 beats/minute, normal with code (2) if the heart rate is between 90 to 110 beats/minute, heavy with code (3) if the heart rate ranges from 110 to 130 beats/minute, very heavy with a score of (4) if the heart rate ranges from 130 to 150 beats/minute, and extreme severe with code (5) if the heart rate ranges from 150 up to 170 beats/minute.The workload classification analysis using SPSS in table 10 shows the results of the moderate and heavy categories of frequency.Medium category with a total of 7 and heavy with 23.So that 76% of the coconut husk stripping work activity is a category of heavy and tiring workload for the work.

Posture Improvement Recommendations
Recommendations for improving posture are carried out by human simulations and integrated into the tool by considering the angular limitations and the preferred angles.The recommended tool height is 90 cm so that the worker does not bend his body to extremes when using the tool.The position of the lever adjusts to the length of the reach of the worker's hand so that the worker's shoulder is not lower and the worker's hand does not experience excessive flexion and rotation.The following are recommendations for improving posture considering the angular limitations and the preferred.

Conclusions
The work posture analysis results show that workers carrying out coconut husk stripping activities have the highest risk level, with a RULA score of 7 (red).This means that the work has the highest risk of fatigue and MSDs, so repairs must be made immediately.Based on the analysis of the classification of physical workloads, it shows that 76% of the coconut husk stripping work activity is a heavy and tiring workload category for the work.The proposed improvement in posture shows a decrease in the score to 3 (yellow), which means the work is quite tiring.However, the workers do not accept excessive muscle tension hence the proposal can reduce the level of posture risk from high to low.

Fig. 4 .
Fig.4.Coconut Coir Stripping Work Posture Workstation Based on the body posture of stripping coconut husk above, several angles of flexion/extension are formed by the worker's body.The angle formed by lower back 37.40, thoracic 12.60, head 10.50, right thigh -180, left thigh 21.70, left leg 24.20, right arm 74.30, left arm 76.90, right forearm 39.30, left forearm 36.170,right hand -39.60, left hand -37,180.The results of the analysis using CATIA software can be seen in Figure 4.

Fig. 5 .
Fig. 5. RULA Analysis of Coconut Coir Stripping Work Posture The body position of workers stripping coconut husks in a bent position can cause thoracic muscle fatigue in the left and right body muscles.That is because the lower back muscles are pulled up when bending over.Tabel 1. is a description of the results based on the RULA analysis output.

Fig. 6 .
Fig. 6.Coconut Shell Cutting Workstation In cutting the coconut shell above, several flexion/extension angles are formed by the worker's body.The angle formed by the thoracic is 10.60, head 17.40, right thigh 1130, left thigh 1130, left leg 131.90, right leg 1350, left arm 53.70, right forearm 108.50, left forearm 28.30.The results of the analysis using CATIA software can be seen in Figure 6.

Fig. 7 .
Fig. 7. RULA Analysis of Coconut Shell Cutting Working Posture The position of the worker cutting coconut shells in a squatting sitting position can cause thoracic muscle fatigue and leg muscles on both the left and right sides of the body.That is because the lower back muscles are pulled up when a bent sitting position is squatting.The following describes the results based on the RULA analysis output.
this part of the body does not receive excessive muscle tension but must be considered.The forearm scores 2 (yellow) and 3 (red) because it is experiencing muscle fatigue at work, so it requires immediate corrective action.The wrist has a value of 1 (green) and 2 (yellow), which means that the wrist does not experience fatigue but must be considered.Overall the posture of the upper arm, forearm, and wrist for the right side of the body does not have significant muscle fatigue.However, the arms and wrists on the left side of the body have muscle fatigue potential to get injured due to pressure from repetitive movements and need to change in the future.The neck, body, and legs have a value of 3 (yellow), meaning that the body part does not have muscle fatigue.The final analysis of the working posture of cutting coconut shells has a value of 3 and 4 (yellow), which means that overall, this posture is quite tiring and needs attention.

3. 1 . 3 Fig. 8 .Fig. 9 .
Fig. 8. Coconut Meat Shredding Work Posture Simulation Based on the posture of shaving the coconut meat above, several angles of flexion/extension are formed by the worker's body.The angle formed by the lower back is 3.60, thoracic 14.80, head 13.090, right thigh 900, left thigh 900, left leg 900, right leg 900, right arm 53.70, left arm 58.80, right forearm 660, left forearm 550, right hand 0, left hand -16,40.The results of the analysis using CATIA software can be seen in Figure 14.

Fig. 10 .
Fig. 10.Working Posture Simulation of Heating Coconut Milk into Coconut Oil Based on the posture of shaving the coconut meat above, several angles of flexion/extension are formed by the worker's body.The angle formed by the lower back is 40, thoracic 90, head 18250, right thigh 0, left thigh 0,

Table 1 .
Description of RULA Analysis of Coir Stripping Work Station Posture

Table 2 .
Description of RULA Analysis of Coconut Shell Cutting Workstation Posture

Table 3 .
Description of RULA Analysis of Coconut Meat Shredding Workstation Posture

Table 4 .
Description of RULA Analysis of Workstation Posture Heating Coconut Oil into Coconut Oil

Table 5 .
Working Heart Rate Measurement Data (Pulse/Minute)

Table 6 .
Job Classification by Type of Workload Criteria

Table 7 .
Output Heart Rate of Coconut Coir Stripping Workers

Table 8 .
Description of RULA Analysis of Posture Improvement