# Design and Control Simulation Analysis of Tender Tea Bud Picking Manipulator
## 1 Introduction  
Tender tea buds have always been popular as a pure and high-end beverage and continue to maintain a high market demand. However, in the production of tender tea buds, the picking of tender tea buds has been a pain point for the industry. At present, tender tea bud picking is primarily manual. The picking quality is high, but taking into account that tea is a seasonal product, it is challenging to accommodate the large-scale and labor-intensive recruiting necessary during the tea-picking period. Machine-picked tea mostly compounds the cutting efficiency but at low quality, as the blade cutting will lead to the destruction of the cell structure of the tea leaves, prompting the tea to undergo oxidation faster so that it loses the fresh green appearance and pure taste, and often machine picking is only suitable for bulk tea. Selection, therefore, requires a picking robot to meet the requirements of tender tea bud picking. As the vital actuator of the robot, the manipulator needs to face the complex picking environment and picking demand. Therefore, the accuracy, stability, and rapidity of the controller have stringent requirements [1; 2; 3]. The current control methods of the robotic arm have fractional-order PID control, particle swarm optimization fuzzy PID control,adaptive neural PD control, and other practices [4; 5; 6; 7; 8; 9]. Due to the complexity of their algorithmic parameter design, computational costs, and other issues, they are mostly not applicable to the application of tea-picking machinery. At present, domestic and foreign research on tender tea buds-choosing robotd is scarce. Considering the inherent characteristics of tea shoots, the existing picking robot volume is large, it is complicated to reach into dense tea bushes, and clamping quickly damages the tea stalks, posing a greater challenge to complete the picking of tender tea buds [10; 11; 12; 13]. Therefore, there is a need to design a picking robot. In the paper [14; 15; 16], the picking robot was redesigned to increase the flexibility and applicability of picking by combining the characteristics of the picking targets, but the use of blade-cutting picking did not meet the needs of tender tea bud picking. [PERSON] et al. [17] designed a soft grasping bionic robot that demonstrated soft contact mechanical behavior during gentle grasping but with large errors in terms of small target grasping. [PERSON] [18] designed a bionic four-finger picking manipulator, imitating the artificial \"hand-picking\" method, but due to mechanical errors, it is more difficult to hold the rootstock of the shoots accurately, and the damage to the rootstock of the nodes is more significant, which cannot meet the standard of picking tender tea buds. [PERSON] et al. [19] designed a bionic three-finger selecting actuator by reproducing the three-finger picking actuator; the control method is simple, but the disadvantage is that the fingertip holding force control is not precise, and the tea shoots still easily fall off in the process. In summary, the above manipulator in picking tender tea buds, due to the improper picking method and control method, will cause damage, affecting the quality of tender tea buds and increasing the cost of picking. Therefore, this paper designs a new type of tender tea bud-picking robot and proposes a new picking method. The main innovative work of this paper is as follows:  
(1) We designed a tender tea bud-picking manipulator with the use of SolidWorks 2021 software 3D modeling to verify the reasonableness of the mechanical structure. Also in this paper, in the study of the natural growth characteristics of tea and the analysis of the traditional manual picking practices based on the proposed 'rotary pull-up' clamping and ripping picking method, PVDF piezoelectric thin film sensors are applied to determine the picking clamping force to simulate the human finger in the selection of the tender tea buds.