Authors

Abstract

At present, the oblique seedling picking-and-release device of vegetable transplanters has low positioning accuracy and poor stability, which easily leads to issues such as failing to pick, damaging seedlings, and breaking seedling grippers during operation. Conventional PID control is difficult to meet the positioning control requirements. A step positioning control system based on fuzzy PID was designed, the transfer function of the control system was determined, and a fuzzy PID controller was established. Simulation analysis shows that with the displacement of the seedling picking-and-release frame as the system input, under optimal parameters, the times to reach steady state taken for conventional PID control and for fuzzy PID control are 1.2 s and 0.5 s, respectively. Field test results show that under fuzzy PID control, the maximum displacement error is reduced to 2.6 mm, with a relative error of 1.24%, which is less than the maximum relative error allowed for the displacement of the seedling picking-and-release frame. Fuzzy PID control has a shorter adjustment time, enabling rapid and precise positioning of grippers, and improving the success rate of seedling picking. The research results can provide reference and basis for the development of the control system for seedling picking-and-release device.

Abstract in Chinese

目前，蔬菜移栽机斜置式取投苗装置定位精度差、稳定性低，容易出现漏苗、伤苗、取苗爪损伤等问题。常规PID控制难以满足定位控制要求。本文设计了一种基于模糊PID的步进定位控制系统，确定了系统的传递函数，建立了模糊控制器。仿真分析表明，以取投苗臂位移为系统输入量，在最优参数条件下，常规PID控制和模糊PID控制系统到达稳态的时间分别为1.2s和2.5s。田间试验结果表明，采用模糊PID控制，取投苗臂最大位移误差为2.6mm，最大相对位移误差为1.24%，小于取投苗臂允许的最大相对位移误差。模糊PID控制缩短了调节时间，实现了取苗爪的快速精准定位，提高了取苗成功率。研究结果可为蔬菜移栽机取投苗装置控制系统的开发提供参考和依据。