Development Of Automatic Machine For Placing Seed Trays Using Suction Cups

Transplant production is an important part of agriculture The work of placing seed trays is tedious and time-consuming,and it is simple and repetitive.It is necessary to realize mechanization and automation.Low-cost plastic seed trays are widely used in China.Machines which could realize the place seed trays automatically have advantages and disadvantages,and they are not widely used in china.Therefore,it is necessary to carry out the related research.This research aims to achieve placing seed trays with 50 holes automatically.The following four aspects were carried out in this research:(1)To determine the overall scheme of the automatic machine for placing seed trays using suction cups.The requirement analysis was carried out,and the design requirements were determined.According the order of picking scheme,trays supply scheme,control requirement,determined the overall program?The scheme of picking the first seed tray from the top was selected;a normal box was selected to order seed trays for the machine;a conveyor was selected to convey a single seed tray for the seeder;a mini hoist and a rope wheel mechanism were selected to realize vertical and horizontal movement institutions respectively,both with the slide block;a single-chip microcomputer was selected as the controller chip.The selection of the overall scheme of the automatic machine for placing seed trays using suction cups was completed.(2)The main parts of the automatic machine for placing seed trays using suction cups were designed.The pneumatic system of the machine was designed.The ZQ370-02 PM vacuum pump was selected as the vacuum element,and the characteristic of the pump's output vacuum and no-load flow with the input voltage is tested.And the adjustable suction cups holder was designed,which could worked in four different adsorption positions.The motion device was designed,the ANSYS Workbench software was applied to analysis the key components and the key parameters of components were determined.Two 304# stainless steel tube with the 16 mm outside diameter and 14 mm inner diameter were applied as the vertical guide rod,two straight rolling bearing with flange coordinated.The rope wheel mechanism was designed and two straight rolling bearing were applied in horizontal.The motion device with two degrees of freedom was made.(3)The control system of the automatic machine for placing seed trays using suction cups was designed.According to the overall scheme and the design requirements,the control scheme was determined.The control system hardware circuit was designed,using STC89C52 RC microcontroller as control chip;two phase 42 stepper motors were applied as the actuator,working with the ZD-6209-V2 C drivers.And according to the requirements of sensors,selected the limit switches,the reflection type infrared sensor switches,and the opposite type infrared sensor switch were selected as sensors.The control system hardware circuit was designed and the circuit board was welded.The software of the control system is debugged,and the software debugging and the software-hardware debugging were completed.The automatic control requirements of the machine was realized.(4)The prototype of the automatic machine for placing seed trays using suction cups was produced and the test research was carried out.The tests presented that four and three suction cups is better than the double suction cups.The change of position during four suction cups could not affect the success rate of placement,and small distance is the best solution.When using the three floor organ type vacuum suction cups,the springs do not affect the success rate.When using four 9mm three floor organ type vacuum suction cups,the voltage does not affect the success rate.18.0±0.05 V is the best voltage according to the characteristic of the pump.When using four 9mm three floor organ type vacuum suction cups,with the voltage of 18.0±0.05 V,placing 500 times,the successful rate is 99.6%.Placing machine's working efficiency is 400/h,the success rate under the conditions of four the suction cups can reach more than 99%.