## 1 Introduction
[13] used ANSYS/LS-DYNA to conduct numerical calculations and simulations on a finite element model composed of different cutting angles and speeds in the sugarcane cutting process. [PERSON] et al. [14] used ANSYS/LS-DYNA to simulate a circular saw blade model under different conditions for the cutting of multipery branches and determined the optimal parameters for the circular saw blade. Based on a Box-Behnken design experiment, [PERSON] et al. [15] established models for the sugarcane cutting process which simulated the cutting resistance and stress distribution of blades and sugarcane under different factors. These models were used to determine the optimization parameters according to sugarcane cutting quality and the average maximum cutting power consumption. [PERSON] et al. [16] used LS-DYNA software to simulate the picking process of a carp-clip safflower picking device and revealed the relationship between the different structural and working parameters of the picking device and the safflower movement type. [PERSON] et al. [17] carried out finite element analysis of the interaction between harvester rods and coffee branches using ANSYS/LS-DYNA software and tested the samples with plagiotropic coffee branches. [PERSON] et al. [18] studied the dynamic impact of the apple using the finite element method and carried out the apple collision tests. The FEM method involves the encryption of the mesh of the contact part, focusing on material failure and damage in the cutting process. This simulation method is generally based on element deletion technology, which ignores conservation and, to a certain extent, affects the accuracy of the cutting force analysis. The SPH algorithm does not have the mesh distortion and element failure problems and, in comparison with other methods, has very significant advantages in terms of failure types [19; 20; 21]. However, because of the algorithm differences, the computational efficiency of the SPH method is low and boundary conditions are difficult to solve. For this reason, some scholars have proposed the SPH-FEM coupling method [22; 23; 24]. The FEM algorithm is used to solve the low-speed deformation region in the model analysis, and the SPH algorithm is used to solve the high deformation, high speed, and difficult FEM calculation region. The advantages of the two algorithms, such as a low speed, small deformation area, accurate Lagrange solution, fast solution speed and a large deformation area to avoid the increase in computational load caused by mesh distortion, are fully used to solve the coexisting coupling problems of large deformation, impact, small deformation, etc. Based on the above summary, the cutting system is the most important part of castor harvester picking devices and affects the performance and power consumption of castor harvesters. Focusing on wave-type disc cutters of the designed cutting system, the cutting process was analyzed and the parameters optimized. The objective of this paper was to perform a simulation of the castor stalk-cutting process using the coupled SPH-FEM numerical calculation method based on stalk physical characteristics [25; 26; 27; 28] and then to optimize the structural and operating parameters of the disc cutter using the orthogonal rotation combination test. Finally, the numerical computer simulation results were verified via experimental tests.