Control Method for Seedling Tray Positioning in Top-clamping Seedling-taking Device Based on Fuzzy PID
In response to the demand for precise conveying and positioning for seedling trays in top-clamping seedling-taking devices,an accurate positioning control method based on fuzzy PID and dual sensors was proposed,which obtained the position information of seedling trays by a laser sensor and got corresponding angle information by an angle sensor.Moreover,a fuzzy PID control model based on a two-phase hybrid stepper motor was established to convey the seedling trays accurately.Taking the standard 128-cell seedling tray as the conveying object,the positioning accuracy of the seedling tray was analyzed,which showed that the positioning error of the seedling tray should be less than 2.13 mm,corresponding to the angle control error of less than 2.03°.Subsequently,the control system for seedling tray positioning was analyzed and established based on the working principle of the top-clamping seedling-taking device.The simulation results showed that under the optimal PID parameters,KP=40,K,=76,KD=3.2,the adjustment time of fuzzy PID control was 0.18 s,the recovery time after disturbance was 0.31 s,and the maximum response variation was 0.94°,which was less than 2.03°.The fuzzy PID had a better dynamic and steady-state performance than the classical PID,meeting the control requirements.The positioning control results showed that the fuzzy PID achieved an average positioning error of 0.32 mm,an average relative positioning error of 0.92%,and a maximum positioning error of 0.53 mm,which was less than 2.13 mm.This method can meet the requirements for precise positioning of seedling tray conveying,enhancing the system's anti-interference capability and providing a reference for the key technology upgrade of automatic vegetable transplanters.
transplanterseedling taking by ejecting and clampingseedling tray positioningdual sensorsfuzzy PID
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