## 2 Materials and Methods
### Contact Parameters  
#### 2.3.1 The Coefficient of Friction  
The coefficient of static friction refers to the ratio of the maximum static friction force to the normal force between two surfaces, providing a reliable indication of the frictional properties between a material and the contacting solid surface. Since slicing and other preprocessing equipment used for FTB after harvest are primarily made of stainless steel plates and industrial rubber, this study employed the inclined plane method to evaluate the coefficient of static friction [28] between FTB and these two contact surfaces. A friction testing apparatus [19; 29] equipped with a high-speed camera (The manufacturer of the Phantom high-speed camera is Vision Research, Inc., which is located in Wayne, NJ, USA. )and a protractor(The manufacturer of the protractor is Ming Sen Company, which is located in Ningbo, Zhejiang, China.) was used to measure the critical angle, as shown in Figure 3. Ten randomly selected FTB samples were used in the test. At the initial stage of the experiment, the stainless steel plate and industrial rubber were placed on the apparatus, and the FTB sample was placed in a stationary position on the contact surface. The angle of the device was then gradually increased at a uniform speed until the sample showed  
Figure 2: Uniaxial compression test. 1. Flat probe. 2. FTB sample. 3. Base platform. signs of sliding. The critical angle at the onset of slipping was recorded using a high-speed camera. \[f=\frac{mg\sin\alpha}{mg\cos\alpha}=\tan\alpha \tag{3}\]  
Each FTB sample was tested three times, during which the angle formed between the plate surface and the horizontal surface was recorded. Based on Equation (3), the static friction coefficients between FTB and the stainless steel plate (\(f_{1}\)), as well as between FTB and industrial rubber (\(f_{2}\)), were determined through a total of 30 tests, yielding values of 0.63 and 0.66, respectively. To evaluate the coefficient of rolling friction between FTB and the stainless steel plate, a combined approach involving the inclined plane rolling method and the law of conservation of energy was used. The friction apparatus was fixed at an angle of 25\({}^{\circ}\) (\(\theta\)), allowing the FTB sample to roll down the inclined surface of the stainless steel plate with an initial velocity of zero. As illustrated in Figure 4, the sample eventually came to rest at a certain point along the plate due to the effect of friction. The coefficient of rolling friction (\(\mu\)) can be calculated through the law of conservation of energy, with the distance \(M\) traveled by the sample on the inclined stainless steel plate being 150 mm, and the final position \(P\) representing the point where the sample remains stationary on the plate. Given the irregular shape of FTB, which cannot be simplified to a simple spherical model, the rolling trajectory on the horizontal plane tends to deviate from a straight line, making it challenging to measure the accurate path. Consequently, a large number of experiments were conducted, and 10 sets of data with reasonably straight rolling paths were selected for analysis [30]. The calculation is based on Equation (4):  
\[mgM\sin\theta=\mu_{f}mg(M\cos\theta+P_{0}) \tag{4}\]  
Figure 4: Rolling friction test of FTB. 1. Stainless steel plate. 2. Friction apparatus. 3. Initial position of the FTB sample. 4. Final resting position of the FTB sample after rolling. Figure 3: Static friction test of FTB. (**a**) Friction test between FTB and the stainless steel plate; (**b**) friction test of FTB with industrial rubber. 1. Friction testing apparatus. 2. High-speed camera. 3. FTB sample. 4. Protractor. 5. Stainless steel plate. 6. Industrial rubber.