# Research on Space Maglev Vibration Isolation Control System Modeling and Simulation
## 2. Maglev Vibration Isolation System Design
### Coil Structure Design  
The coil is the key structure of the actuator, which determines the output characteristics of the actuator. There are mainly two types of coil structures for actuators, including PCB coils and wound coils. PCB coils are wound by copper deposition in the PCB. Based on mature PCB technology, the coil winding has strong compactness and good consistency.  
\begin{table}
\begin{tabular}{c c} \hline
**Item** & **Performance Indicators** \\ \hline \multirow{2}{*}{Current Range} & High precision: \(-0.1\) A \(<\) I \(\leq\) 0.1 A \\  & Large current: \(-3.5\) A \(\leq\) I \(\leq\) 3.5 A \\ \hline \multirow{2}{*}{Current Accuracy} & High precision: 0.15 mA (\(-0.1\) A \(<\) I \(\leq\) 0.1 A) \\  & Large current: 2 mA (\(-3.5\) A \(\leq\) I \(\leq\) 3.5 A) \\ \hline \multirow{2}{*}{Power} & \multirow{2}{*}{360 W} \\ \end{tabular}
\end{table}
Table 1: Controller current performance indicators.  
Figure 7: Magnetic simulation.  
However, the heat dissipation characteristics of the PCB board are relatively poor, which is not conducive to the actuator working in a peak output state for a long time. The wound coil has a large overcurrent capacity, and the gap between the windings ensures that the coil has good heat dissipation characteristics. However, each layer of coil requires a separate coil skeleton; thus, with the same number of output channels, the size of the wound coil is relatively larger.  
Due to the requirement for the actuator to have a bidirectional force output function and both high and low current output modes in one direction, PCB coils are chosen to have a bidirectional four-channel output function. For the convenience of coil heat dissipation, the high-force coil is arranged outside, while high-precision coils are arranged inside. According to the above coil design scheme, the output force of the actuator can be expressed as:  
\[F=F_{xL}+F_{xS}+F_{yL}+F_{yS} \tag{1}\]  
\(F\) is the resultant force output by the actuator; \(F_{xL}\) and \(F_{xS}\) are the high-force values and high-precision force outputs of the transverse coil, while \(F_{yL}\) and \(F_{yS}\) are the high-force values and high-precision force outputs of the vertical coil.  
According to the 50% derating design, the rated current and current densities corresponding to enameled wires with wire diameters of 0.2 mm, 0.3 mm, and 0.4 mm are shown in Table 2.  
According to the simulation results, the ampere turn is 280 A. The parameters such as coil cross-section, outer diameter of enameled wire, and number of coil turns are shown in Table 3.  
The rated current is 1.2 A, and the number of ampere-turns is 238 \(\times\) 1.2 = 285.6, which can achieve the ampere-turns in the simulation model.  
The coil is made by winding enameled wire around the coil skeleton. By selecting the diameter of the enameled wire, the coil can ensure a large overcurrent capacity. A high current will generate a large amount of heat. Considering the thermal effect, the gap between the windings can ensure that the coil has good heat dissipation characteristics.