# Design and Test of Seeding-Picking Mechanism of Fully Automatic Transplanting Machine
## 1 Introduction  
The agricultural practice of vegetable transplanting involves transferring seedlings from nurseries, where they have continued to develop, to the field. A crucial tool in this process is the transplanter, which is essential for timely cultivation and saving labor [1]. Machine transplanting is more efficient than direct souring, because it requires less labor, resulting in more consistent vegetable yields. Numerous devices and tools have been specifically developed for this task [2]. Additionally, using transplanting instead of direct souring mitigates the risks associated with natural disasters, such as low temperatures and cold spells in spring, yet also enhancing seedling survival and crop quality [3]. The seedling transfer device serves as a transportation bridge between the nursery unit and the planting unit [4]. Within this device, the component most prone to issues is the seedling-picking mechanism. A well-designed and efficiently operating seedling-picking device is essential for achieving full automation of the transplanter and enhancing operational efficiency [5]. Currently, transplanting machinery in China is predominantly characterized by semi-automatic transplanting technology, with seedling planting largely relying on manual processes [6]. Consequently, there is an urgent need to design an automatic seedling-picking device to replace manual seedling feeding [7]. The transplanters currently under study exhibit distinctive features and advantages tailored to the specific circumstances of each country. In Europe, the United States, and other nations, where land is more concentrated and comprises larger fields, research on automatic transplanters predominantly focuses on wide, high-speed, large-scale, and integrated mechanical-electrical-hydraulic-automation technologies [8; 9]. For instance, FERRARI in Italy has developed the FUTRA fully automatic translpanter [10], which boasts a high degree of automation and employs an ejecting-clamping seedling-picking and dropping mechanism. This transplanter can achieve an impressive operational efficiency of up to 4500 crops per row per hour. However, its large size renders it unsuitable for smaller fields in China. In contrast, a two-degree-of-freedom five-bar seedling extraction device was developed in [11], which, yet simple, is not designed for high-speed seedling extraction. Additionally, a two-finger gripper for a wide range of vegetable seedlings was tested primarily on leeks and fennel [12]. In Japan, due to local constraints, transplanters tend to be compact, purely mechanical, and lack intelligent features [13], resulting in lower seedling extraction efficiency. It is important to note that foreign-designed seedling extraction mechanisms are typically developed for the specific conditions of their respective countries and may not be suitable for crop applications in China. Currently, domestic seedling extraction mechanisms for transplanting machines primarily include two types [13; 14; 15]: pneumatic and mechanical types. The pneumatic seedling extraction mechanism exhibits relatively low efficiency due to the limitations of its actuators and other components. In contrast, mechanical seedling pickup mechanisms can compromise extraction accuracy due to wear and tear on their components. This study presents a whole-row automatic seedling extraction device characterized by a simple structure, enhanced efficiency, effective seedling extraction, and minimized damage to potted seedlings. Through simulation and platform construction, we conducted a performance test of the entire machine, confirming the device's rationality [16]. However, the combined design of the seedling extraction device introduces a greater number of moving parts, necessitating higher machining and installation precision. Furthermore, the components must exhibit a high level of cooperation, which leads to slight jittering and jamming issues during the debugging process.