Design And Experimental Research Of Self-propelled Cabbage Harvesting Test Platform

Cabbage is a vegetable that is extensively cultivated in China,and in 2019,China ranked first in terms of cabbage cultivation area in the world.However,compared to the cultivation scale,the mechanization level of cabbage production in China is seriously lagging behind.The harvesting process of cabbage requires the greatest labor intensity,and traditional manual harvesting is time-consuming and labor-intensive.However,the development of cabbage harvesting machinery is still in the research and development stage in China,and there are issues such as uncontrollable external factors in field trials,poor universality of harvesting machinery,and high harvesting damage in harvesting experimental research.Therefore,there is an urgent need to develop a cabbage harvesting test bench with workpieces and adjustable and controllable parameters,which can be used for integrated experimental research on the structure and motion parameters of pulling,clamping,conveying,and cutting roots.To address these issues,this article takes the cabbage variety widely cultivated in the eastern region of China as the research object and designs a self-propelled cabbage harvesting test bench from the perspective of practical experimental needs,undertaking all the work of test bench design and trial production.The main research contents are as follows:(1)This study conducted a summary analysis of the physical and mechanical characteristics of common cabbage planting varieties and planting patterns in the eastern region of China.Based on this,by referring to mature foreign models and related prototype literature at home and abroad,the working principles and work plans of key components of the cabbage harvesting test bench were determined,and the overall scheme of the harvesting test bench was designed.The cabbage harvesting test bench designed in this study is purely electrically driven,with a maximum operating speed of 0.35 m/s and a rated power of 4.24 k W.The harvesting section adopts a singlerow operation mode,using a roller-type pulling device in combination with a weed removal wheel to complete the cabbage pulling process.Subsequently,the cabbage is clamped and conveyed by a double horizontal conveyor belt type clamping and conveying device,and finally,the cabbage roots are cut off by a double disc cutting knife to complete the harvesting operation of the test bench.(2)Based on the overall plan of the cabbage harvesting test platform and with reference to the physical and mechanical properties of common cabbage varieties and planting patterns in East China,a variable adjustable picking mechanism suitable for various planting environments and cabbage sizes was designed through parameter analysis and structural development.A variable adjustable clamping conveyor mechanism was designed for flexible and floating clamping of cabbage stems according to the cabbage size.A variable adjustable root-cutting mechanism with adjustable cutting height and overlapping distance of the cutting blades was also designed.The whole machine of the test platform was manufactured and tested.The adjustable picking device designed in this article can adjust the angle of the picking roller,the opening angle of the picking roller,the horizontal opening angle of the guide rod,and the vertical opening angle of the guide rod.The adjustable clamping conveyor device can adjust the clamping and conveying distance、 the angle with the ground.The adjustable root-cutting device can adjust the overlapping distance of the cutting blades and the distance between the cutting blades and the conveyor belt.With these adjustable structures,the cabbage harvesting test platform developed in this article can have a certain degree of versatility for cabbage harvesting tests of different varieties and planting patterns.In addition,a self-propelled cabbage harvesting test platform control system was built according to the test requirements of the cabbage harvesting test platform,which enables real-time adjustment and monitoring of the motion state of the key harvesting components of the test platform.(3)The control system performance,and harvesting effect of the cabbage harvesting test platform were tested,and the results showed that the maximum speed of the harvesting test platform was 0.34 m/s,and the maximum actual error of the driving motor speed of the key harvesting mechanism of the harvesting test bench is within 5%.The acceleration time was 11.38 s,and the acceleration distance was 3.35 m.The braking distance of the harvesting test platform was 0.55 m,and the braking time was 1.44 s.The maximum actual error of the driving motor of the key harvesting mechanism of the harvesting test platform was within 5%,and the maximum error rate of the left and right motor speeds of the picking roller driving motor,the active drum driving motor,and the cutting knife driving motor was within 3%.The cutting knife speed and the pre-tightening force of the tension arm significantly affected the cabbage harvesting effect.The qualified cutting rate increased first and then decreased with the increase of the cutting knife speed.When the cutting knife speed was 320 r/min,the qualified cutting rate was the highest at 95.24%.The damage rate decreased first and then increased with the increase of the pre-tightening force of the tension arm.When the pre-tightening force of the tension arm was 100 N,the damage rate was the lowest at 3.70%.Through the study of the self-propelled cabbage harvesting test platform,an indoor cabbage harvesting test platform that can perform adjustable and controllable structural and motion parameters for multiple varieties and agronomy of cabbage harvesting tests was designed in this paper.This provides technical support for the development of cabbage harvesting machinery in China.