# Design of Man-Machine Synergic Lunar Coring Device and Its Coring Dynamic Analysis
## 4 Dynamic Analysis and Verification of the Coring Device
If the impact energy is fully released at time \(t_{2}\), the required length of the gentle section of the cam to ensure that the impact energy is fully released before loading is:  
\[l_{\alpha}=\pi R(1-\alpha)\geq\pi R\lambda(t_{1}+t_{2})+2r \tag{6}\]  
At present, the rated torque of the impact module motor is 10 Nm, and the speed is 0-1000 rpm, while the estimated mass is 0.9 kg based on the 3D model of the impact hammer and the cylindrical cam. If 5 ms is reserved for the impact hammer impact energy release process, the boundary conditions for the cam height, spring stiffness, and spring preload length can be obtained from Equations (1) and (4), as shown in Figure 10a,b. By limiting the size of the structural dimensions under the boundary conditions, the structural design parameters that can achieve the maximum impact energy under the boundary conditions can be found, as shown in Figure 10b. The optimized structural parameters of the impact mechanism are shown in Table 3. After optimization, the theoretical maximum single impact energy can reach 14.9 J, which can realize the impact coring effect well. Simulation of the impact process of the simulated lunar rock was carried out in ANSYS Workbench according to the optimized in-structure parameters. The coring and drilling tube materials are chosen as steel material, and the simulated lunar rock is taken as sandstone material. The lunar regolith will not be an entirely loose l \begin{table}
\begin{tabular}{c c c c c c} \hline
**Motor Torque \(M_{d}\)** & **Impact Frequency** & **Cam Height** & **Preload Height \(l_{0}\)** & **Spring Elastic Stiffness** & **Impact Mass** \\
**(Nm)** & **\(\lambda\) (Hz)** & \(h\) (mm) & **(mm)** & \(k\) (N/m) & \(m\) (kg) \\ \hline \(10\) & 20 & 25 & 10 & 30,000 & 0.9 \\ \hline \end{tabular}
\end{table} 
Table 3: Relevant parameters of the optimized impact structure. intermixed with fragmented lunar rocks. If coring tools cannot penetrate the lunar rocks, the coring mission will fail. Therefore, the coring device should perform experiments on the coring performance of simulated lunar rocks to ensure the feasibility of the schemes. According to the lunar rock samples obtained at present, the structure and genesis of lunar rocks can be divided into three categories, namely crystalline igneous rocks, breccias, and lunar soils or moon dust. The simulated lunar rocks have similar mineral composition and chemical composition, similar density, shear modulus, mechanical strength, and Poisson's ratio as the replica of the experimental properties of the lunar samples. The parameter settings of the simulated lunar rock part are shown in Table 4.  
According to the current international research on lunar coring devices, it is found that the coring process for lunar surface regolith is relatively simple, requiring only 2-4 J of impact energy, and both the coring tube and the drilling tube can achieve the coring work well. However, in the case of hard lunar rocks, the choice of the coring method is significant for the success of the coring process. Therefore, the focus was on coring simulation experiments for simulated lunar rocks. After setting the material parameters of the model, the coring/drilling tube and the simulated lunar rock have meshed, as shown in Figure 11. For the simulated lunar rocks with fixed constraints around the perimeter, the coring and drilling tubes are subjected to the pressure exerted by the coring device regardless of the coring method used (about 200 N, not considering the pressure exerted by the astronauts). When using the coring tube impact penetration method, a certain amount of impact energy (about 14.9 J) is applied to the coring tube. If the coring tube impact rotary penetration method is used, a certain additional rotational speed (300 rpm) is applied to