## 3 Results and Discussion
### Simulating the Physical Ergonomic Conditions of Assembly Procedures in VR and DHM
#### 3.1.1 Creation of CAD Models and Scenarios  
For the virtual analysis to accurately reproduce the physical one, scenarios containing all the details linked to the assembly procedures must be created before running the simulation. The key point here is to ensure that all assembly procedure parts, particularly the worker, are correctly positioned [4]. All workplace tools and facilities, the sequence of assembly procedures, and all tasks involved in such a study should be mapped, photographed, and recorded [21], and these data should be examined to determine which elements will be exported to the CAD model. The simulation captured an image from physical assembly procedures that cover all relevant workplace information, such as the assembly sequence. Tools are essential in the execution of assembly procedures, such as those found in the automotive industry. Some tools used in this simulation include pliers, portable nutrunners, torque wrenches, spanners, and special tools (Figure 2). Figure 2: Workplace tools. The industrial facilities and resources are equally important for the execution of working tasks. Tool carts, shelves, roller racks, and skids are examples of those features shown in Figure 3.  
Continuing the photographic mapping of the physical assembly procedures, the sequence conducted by the worker in each of the four procedures was described. Only the most important steps of each procedure are shown in the pictures. In addition, the process videos were used to conduct the simulation. The first procedure assembly is the Front Driveshaft, in which the worker must pick up the fasteners and parts from the shelves, align the parts with the transfer case flange, and take a manual pre-torque (using hands), with a torque meter and device to rotate the set and apply torque in all screws; and, finally, the worker must mark the torqued nuts with sealing paint (Figure 4). The Rear Driveshaft assembly procedure is quite similar to the Front Driveshaft assembly, with the key difference being that workers must move heavy parts from storage to the workplace. The Rear Driveshaft must be aligned in differential and connected, with the pre-torque applied with a spanner (Figure 5). Figure 4: Front Driveshaft assembles. Figure 3: Workplace resources and facilities. The radiator hose-clamp procedure begins with picking up the hose bracket and tool. The upper half of the hose is fastened in the radiator, and the worker must squat to select the clamp at the radiator's back (Figure 6). The last procedure assembly is to adjust the parking brake; the worker uses portable screwdrivers and a support device to fix inside the vehicle, move the lever up and down ten times, and then align and add the required torque (Figure 7). After mapping and recording the actual workplaces, CATIA V5 was utilized to export three-dimensional (3D) models. As seen in the illustrations below, the first virtual illustration is about the tools needed to finish the assembly. Figure 8 shows the tools' 3D CAD models. Figure 9 shows the industrial facilities and resources that are available, as seen in the conventional method. Figure 10 illustrates the four assembly procedures simulated. The goal is to incorporate manikins and routines into the procedure's execution. Figure 5: Rear Driveshaft assembly. Figure 6: Radiator-hose clamp. Figure 8: CAD models tools. Figure 7: Parking-brake adjustment. Figure 9: CAD models facilities and resources. Once all the elements in the CAD model were created and reproduced in reality, they were imported into Jack and Tecnomatix and built four scenarios, positioning everything that affects worker routine, and then the worker started the simulations. Figure 11 shows scenarios that contain the entire set of information needed to effectively simulate the physical assembly procedures. With Jack, specific analysis tools were used to obtain quantifiable data on postures (joint angles), access (hand release), and force/torque (strength).