# Research and Implementation of CPS for Transmission Front Middle Case Assembly Line
## 5 Application Results and Discussions
### Performance Analysis of the Proposed System  
To gain a more comprehensive and digitized analysis of the proposed system, system performance is verified and described from four different aspects of the completion rate of the process data, the production factor coverage rate, the physical control rate, and the line balance rate. (1) Completion rate of process data  
As a highly-automated assembly line, the workshop had already collected and mastered some data related to the transmission front and middle case assembly line and its operation. However, due to the existence of manual stations and the inability of the workshop MES system to directly and real-time manage the entire operation process of the assembly line, the current data control of the enterprise was still insufficient. The completion rate of the process data is a measure of the degree to which the system can master the process data related to assembly-line operation, such as production resources, logistics, and so on. It is the basis of whether the workshop can control the assembly schedule in real time and accurately. As shown in Equation (1). \[PDCR=\frac{\text{KPN}}{\text{KPNA}}\cdot 100\%, \tag{1}\]  
KPN represents the sum of process elements in a system, while KPNA represents the sum of process elements in an assembly line that needs to be managed systematically. KPNA is divided according to the principle of \"person-machine-material-method-quality inspection\". The specific contents are listed in Table 1. Then the calculations of KPN and KPNA by Equations (2) and (3). \[\text{KPN}=\left(\sum_{i=1}^{n}P_{i}+Mac_{i}+Mat_{i}+Met_{i}+Ql_{i}\right), \tag{2}\]  
\[\text{KPNA}=\sum_{\text{J}}KPN_{j}, \tag{3}\]  
\(n\) is the total number of work steps included in the line, that is, \(i=\{1,2,3\,\dots\,n\}\). \(J\) is the total number of processes included in the line, i.e., \(j=\{1,2,3,\,\dots\,J\}\). (2) Production factor coverage rate  
Production factor coverage rate mainly measures the degree to which the system can master a 3D visualization model of the factors of production, i.e., equipment and parts. It is \begin{table}
\begin{tabular}{c p{284.5 pt}} \hline \hline
**Process** & **Element Point** \\ \hline Person (P) & Each process requires designated person (type of work and quantity), each record counts as a “point”. Each process binding equipment at the station, each equipment counts as a “point”; each process requires a variety of cutting tools, measuring tools, fixtures, etc., and one record counts as a “point”. Each process requires a variety of materials, and one record counts as a “point”. Process drawings, Operating procedures, work steps, appendix, etc., each work step counts as a “point”, and appendix count as a “point”. Quality inspection records for each process, each record counts as a “point”. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Content of process elements. an important index to measure the digitization level of the system and can be calculated by Equation (4). \[PFCR=\frac{\text{TNPFs}}{\text{TNPFI}}\cdot 100\%, \tag{4}\]  
TNPFs represents the total number of 3D visualization models of equipment and parts contained in the proposed system, and TNPFI represents the total number of equipment and parts contained in the transmission front and middle case assembly line. TNPFs can be counted from the project files of material inventories and resource libraries of the system, as shown in Figure 9.  
3. Physical control ratio Physical control is basically similar to process but with slight differences. For example, what is described in the process is the configuration of workers, but the actual number of workers in the physical control, as shown in Table 2. physical control ratio can be calculated by Equation (5). \[PCR=\frac{\text{TNPEs}}{\text{TNPEI}}\cdot 100\%, \tag{5}\]  
TNPEs represents the total number of physical entities controlled by the system, and TNPEI represents the total number of physical entities involved in the transmission front and middle case assembly line.