**4. Conclusions**

(1) The collision material influences the deformation and recovery capacity of wheat during collisions, serving as the primary factor affecting the recovery coefficient in wheat collision experiments. Given constant drop height, material thickness, and moisture content, the elastic recovery coefficient of wheat and rubber in this test is lower than that of wheat and Q235 steel. Therefore, during the mechanical design process for wheat, material selection should be tailored to the specific context.

(2) The falling height dictates the energy changes as the wheat grain collides with the test board material, particularly affecting the size of the wheat shape variable and the movement resistance. When the falling height increases, the grain shape variable expands, and the movement resistance rises correspondingly, leading to a reduced elastic recovery coefficient. The stiffness of the material is determined by its thickness, with an increase in material thickness enhancing the stiffness. When wheat grains come into contact with the

collision material, their energy loss decreases, the initial rebound velocity grows, and, in turn, the elastic recovery coefficient is elevated.

(3) Wheat grains interact with different materials during the collision process, undergoing force deformation and rebound recovery in two separate movement phases. Following the collision, wheat grains may also exhibit rotation and other factors. Consequently, the recovery coefficient of wheat for the same material with varying parameters in the collision material yields a wide range of recovery coefficient changes. The test process revealed that the same wheat grain produced varying test results in multiple tests.

**Author Contributions:** Conceptualization, J.W. and F.W.; methodology, Y.L.; software, W.Z.; validation, B.Z., X.F. and J.W.; formal analysis, W.Z.; investigation, Y.L.; resources, B.Z.; data curation, J.W.; writing—original draft preparation, J.W.; writing—review and editing, F.W.; visualization, Y.L.; supervision, W.Z.; project administration, J.W.; funding acquisition, W.Z. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Key Research and Development Program Project of China (2021YFD2000601).

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.
