## 3 Design of a Lightweight Drive Rod Based on Fully Symmetrical Structure
### Parameters Determination of Lightweight Drive Rod Based on Fully Symmetry Structure  
Parameterize the lightweight drive rod according to its structural characteristics (Figure 13). In consideration of the structural characteristics of the drive rod, assembly space and operating space constraints, the design range of size parameters can be listed (see Table 1). Figure 12: The lightweight drive rod based on fully symmetry structure. Figure 13: Structural parameters of lightweight drive rod. The lightweight drive rod is designed for the 1060 mm \(\times\) 760 mm die-cutting sheet, so it is limited by the transmission distance and mating components, and the two design parameters \"g\" and \"r\" are fixed values. Then, based on the range of the above design parameters, the specific values of each parameter are determined according to the mechanical design principles. First, determine the total width of the drive rod \"b\". Considering the reserved space for the operation of the drive rod and referring to the data of the traditional double-elbow bar, it is determined that b = 250 mm. Second, determine the thickness of the side reinforcement \"a\". There are three reinforcing ribs evenly distributed on the left and right sides of the lightweight drive rod. Based on the design principle of the reinforcing ribs and referring to the data of the traditional hollow double-elbow bar, it is determined that a = 25 mm. Third, determine the thickness of the rotating surface \"c\". According to the force magnitude of the drive rod, combined with the relationship between the force and strain of the material, and on the premise of ensuring the rigidity and strength requirements, it is determined that c = 25 mm. Fourth, determine the thickness \"d\" of the main support wall. The main support surface is mainly used to ensure the stability of the spatial structure during the movement of the drive rod, and its determined value is d = 40 mm. Fifth, determine the total width \"e\" of the stiffener. During operation, the stiffener mainly carries the torque of the drive rod. The greater the \"e\", the stronger the resistance to torque. Considering the reserved operating space, it is determined that e = 110 mm. Finally, determine the reserved slot width \"f\" of the drive rod. Without affecting the smoothness of operation, the smaller the value of \"f\", the better; so, it is determined that f = 51 mm. Summarize the final values of each design parameter based on the above parameter analysis (see Table 2). After completing the above parameter determination, the finite element analysis of the lightweight drive rod is shown in Figures 14 and 15. The results show that compared with traditional drive rod, the stress concentration and strain of lightweight drive rod has greatly improved under the same material and load. Summarize the deformation and weight results of two conventional and lightweight drive rod (Table 3). The results show that the overall performance of the lightweight drive rod is superior to that of the traditional drive rod. In addition, better performance results can be further explored by optimizing drive rod parameters. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Parameter Name** & **a (mm)** & **b (mm)** & **c (mm)** & **d (mm)** & **e (mm)** & **f (mm)** & **g (mm)** & **r (mm)** \\ \hline \multirow{2}{*}{Parameter range} & \(0<a<b-10\) & \(3a+10<b<260\) & \(0<c<\dfrac{g-2r}{2}\) & \(0<d<e\) & \(d<e\leq 2(r+c)\) & \(\dfrac{46<f<}{b-10-3a}\) & \multirow{2}{*}{178} & \multirow{2}{*}{35} \\  & \(\dfrac{b-10}{3}\) & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Design parameters range of the lightweight drive rod. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Parameter Name** & **a (mm)** & **b (mm)** & **c (mm)** & **d (mm)** & **e (mm)** & **f (mm)** & **g (mm)** & **r (mm)** \\ \hline Parameter value & 25 & 250 & 25 & 40 & 110 & 51 & 178 & 35 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Design parameters of the lightweight drive rod.