## 4 Lift-and-Transverse Stereo Garge Based on the Digital Twin
### Digital Twin Modeling of Lift-and-Transverse Stereo Garage  
#### 4.2.1 Definition of Lift-and-Transverse Garage Model  
All the models are realized in the NX CAD module. According to the operation mode of the lift-and-transverse stereo garage, sketching is carried out in the NX CAD module to construct the geometrical 3D model of each part, and the assembly of the parts is completed by setting constraints. In order to build the virtual model, it needs to be imported into MCD first. Adding basic physical attributes to model components is a necessary foundation in MCD. Only after defining the basic object attributes have been defined can you continue to add mechanical, electrical and automation attributes to complete the definition of the electromechanical object. The electromechanical objects are defined as shown in Figure 6.  
Different types of stereo garages operate in different ways, and it is necessary to analyze the operation of lift-and-transverse stereo garages in order for the virtual model to operate as well as the physical entity. In a lift-and-transverse garage, due to the structural characteristics of the garage, the carrier plate on the top level can only move vertically, while the carrier plate on the bottom level can only move horizontally, but on other levels, the carrier plate can move both vertically and horizontally.  
The movement of the carrier plate in each direction needs a motor for control, as shown in Figure 7a-c. The design of the uppermost carrier plate is relatively simple, and only one motor is needed to complete the lifting and lowering operation. Through the motor-driven gear system, the control drum makes the wire rope carry on the retracting and releasing action so as to realize the vertical movement of the carrier plate. At the bottom level, the transverse movement of the carrier plate is also controlled by a single motor, which, through gearing, drives the active rod to rotate, thus pushing the carrier plate along the horizontal direction. In other intermediate layers, the design of each carrier plate is more complex, requiring two motors for complete motion control. One of the motors is responsible for vertical movement, which works in a similar way to the top carrier plate, with the lifting and lowering controlled by a motor-driven gear system. The other motor  
\begin{table}
\begin{tabular}{c c} \hline
**Parameter Name** & **Parameter Content** \\ \hline Equipment Name & Lift-and-Traverse Stereo Garage \\ Storey & Triple \\ Applicable Models & Small/Medium Sedan/SUV \\ Lifting Speed & 75 mm/s \\ Traversing Speed & 125 mm/s \\ Average Access Time & 45 s \\ Driving Method & Motor + Wire Rope \\ \hline \end{tabular}
\end{table}
Table 1: Technical parameters of the stereo garage.  
Figure 6: Definition of virtual model electromechanical objects.  
is used to control the horizontal movement, similar to the movement mechanism of the bottom carrier plate, which is accomplished by the horizontal displacement of the carrier plate through the cooperation of gears and active rods. On the ground level, vehicle access is more convenient and the same as traditional parking space access, but on the other floors, vehicle access needs are met by utilizing the transverse movement of each space to create a dedicated vertical pathway that allows the upper-level target load boards to pass through, thus landing them from the upper level to the ground level.