## 3 Model Establishment
### The Method of Modelling Process
### Initial Workstation Utilization

Using the established workshop simulation model, we evaluated the utilization rates of different workstations during the initial phase. As illustrated in Figure 5(a), the proportion of parts in the buffer remains consistently low when the quantity ranges from zero to nine, staying below 10%. A significant increase is observed only when the buffer quantity reaches 10, at which point the proportion rises to approximately 50%. Figure 6(a) shows that the working time proportions for the three assembly stations, the testing station, and the packaging station are all 6% or less, with the majority of time spent in idle states. This low utilization primarily results from insufficient initial planning and a lack of synchronization between workstations. In the aerospace workshop, substantial differences in processing times across workstations and the inability to consolidate stations with varying tasks contribute to low utilization rates. This inefficiency leads to increased assembly costs and resource waste. Therefore, optimizing the entire complex product assembly workshop is economically essential to

Figure 6: The proportion of the number of parts in the buffer before and after optimization. (**a**) The proportion of the number of parts in the buffer before optimization; (**b**) the proportion of the number of parts in the Buffer after optimization. Figure 7: The utilization rate of each station in the assembly workshop before and after optimization. (**a**) The utilization rate of each station in the assembly workshop before optimization; (**b**) the utilization rate of each station in the assembly workshop after optimization. improve assembly efficiency and reduce overall operational costs. The optimization strategy primarily involves adjusting key parameters, notably increasing the number of AGVs for transporting cabin sections from one to three, while keeping the number of material delivery AGVs unchanged. Additionally, buffer zones are introduced in front of each assembly workstation to alleviate mismatches in processing times. ### Optimized Workstation Utilization

During the optimization process, the number of AGVs was increased while the workload distribution and other related parameters were adjusted through multiple iterations. As a result, workstation utilization improved significantly, rising from less than 6% to more than 26%. Figure 6b shows that the number of parts in the buffer decreased from 11 to 3. When the buffer contained only one part, the proportion rose to approximately 46%, with similar increases observed when the buffer held zero or two parts. These changes helped avoid excessive accumulation in the buffer and contributed to improved production efficiency. As shown in Figure 7b, workstation utilization reaches a peak of over 42% and seldom falls below 26%. Compared to the initial rates, this represents an improvement of up to 36%. The optimized workshop demonstrates a substantial enhancement in production efficiency while contributing to cost reduction. After analyzing the data, we compared the operational metrics of each workstation before and after optimization, as shown in Table 2 and Figure 8. A noticeable increase in the working time percentage was observed across all stations following the optimization. Assembly Station 1 showed the most significant improvement, with a 36.54% increase in working time. This substantial reduction in idle time, particularly at Assembly Station 1, has significantly enhanced the overall production efficiency of the workstations. Several assembly stations were observed to have low workloads. This was primarily caused by discrepancies in task durations, insufficient coordination among workstations, and delays in material supply. Task complexity and processing time varied significantly between workstations. Some stations handled simpler tasks that were completed quickly, resulting in prolonged idle periods, while others faced more complex operations and heavier workloads.