*3.2. Principles of Test Platform*

The operation process of the low-loss harvesting test platform for cabbage is shown in Figure 4. The test platform has preliminarily designed a "vertical clamping + flexible conveying" mechanism suitable for cabbage harvesting, which is mainly composed of a reel, a pulling roller, a flexible clamping belt, a cutterhead, a rack, and a transmission shaft. When the test platform is working, the pulling roller is placed under the outer leaf of the cabbages. The external rotation forces the root of the cabbages to be removed from the fixture to complete the pulling. The flexible conveyor belt clamps the cabbages and transports them backward. The cutter head cuts off the root of the cabbages and completes one test. By changing the material and structural parameters and motion parameters of the key components of the conveying mechanism, the damage to the cabbage after the conveying operation was recorded and saved, and the operation performance indexes such as epidermal damage and cracking ball were measured to find out the mechanism of harvesting damage to cabbage.

**Figure 3.** Structure diagram of low loss harvest test platform for cabbage: (**a**) Harvest cutting table. (**b**) Conveying test bench. (**c**) Harvest header structure diagram: 1: pulling device; 2: flexible clamping device; 3: pulling device; 4: disc cutter; 5: tensioning wheel; 6: track; 7: active shaft; 8: stand; 9: conveyor gear box; 10: pulling device motor. (**d**) Structure diagram of test platform: 1: harvest cutting table; 2: conveying test bench.

**Figure 4.** Test platform operation process.

When the low-loss harvesting test platform for cabbage works, firstly, the servo motor frequency conversion control box controls the working parts of the conveying test bench: the pulling device and the reeling device to run at a lower speed while keeping the clamping conveying device and the cutting device in a static state. At this time, the low-loss harvesting test platform for cabbage can only complete the pulling operation. Observe whether the conveying, pulling, and reeling links of the cabbage are smooth. Combined with the damage to the cabbages in the collection box and the data collection results of the harvesting process, the working parameters of the pulling device or the material of the working parts are adjusted according to the test results until the conveying and pulling links are carried out smoothly and the cabbages are not damaged. Recording the working parameters (motion parameters and structural parameters) of the pulling device at this time is a critical condition for preventing damage to the cabbage in the pulling process. Similarly, according to this method, the servo motor frequency conversion control box controls the speed of the clamping and conveying device and the cutting device in turn, makes the low-loss harvesting test platform of the cabbage, completes the pulling + reeling + clamping and conveying, pulling + reeling + clamping and conveying + cutting links in turn, and records the critical conditions for damage in the clamping and conveying and cutting links, respectively.
