Design Of Adjustable Test Platform And Test Research For Cabbage Root Cutting

Cabbage is one of the main vegetable species in China,and it is widely planted in most parts of our country.At present,the mechanization level of cabbage harvesting in China is relatively low.Cabbage harvesting mainly depends on manual works with low harvesting efficiency,high labor intensity and high operating costs.The cabbage mechanized harvesting generally includes the operations of guiding and straightening,root cutting,lifting and conveying,leaf stripping,etc.,a very important process of which is the root cutting operation.In this paper,an adjustable test platform for cabbage root cutting was designed and built,mechanical simulation of root cutting operation was performed,and the root cutting test research was carried out.This study can provide theoretical basis and reference for the design and improvement of cabbage combine harvester,and is conducive to improving the mechanized harvest level of cabbage in China.The main research contents and conclusions are as follows:(1)Design and build of the adjustable test platform.The adjustable test platform was composed of the mechanical body,the control system,and the signal acquisition and post-processing system.The cutting speed,cutting position,walking speed,cutter overlap amount and pitch angle can all be adjusted,and types of cutters can be changed.This paper mainly designed the adjustable root cutting device,walking device,body chassis,cutter motor control system control module,walking motor control module,electric pushing rod control module and sensor module,and explained the adjustment principle and implementation process of each cutting element.(2)Mechanical simulation of root cutting operation.Based on the explicit nonlinear dynamic analysis theory,the numerical model of root cutting operation was established to simulate the process of root cutting by double disc cutter,and then its mechanical mechanism was revealed.The forces of the disc cutter on the X-axis,Y-axis and Z-axis were analyzed,and the root cutting reaction force F_y?of the disc cutter on the Y-axis was determined as the test data acquisition object.The distribution of effective stress in root cutting process was studied,and it was found that the stress in the contact part between the root and the disc cutter was greater.The numerical results were verified,and the results showed that the numerical calculation results were reliable.(3)Test research for root cutting.Taking“ZaoHong”cabbages as the test research objects,single-factor and multi-factor tests were designed.Choosing the cutting speed,cutting position,walking speed,cutter overlap amount,pitch angle and cutter type as independent variables,a single-factor test was performed to obtain the influence law of single factor on the maximum root cutting reaction force.The second-order orthogonal rotating combination multi-factor tests were carried out to study the influence of cutter speed,cutting position,walking speed,cutter overlap amount and pitch angle on the maximum root cutting reaction force.The mathematical model of the relationship between the maximum root cutting reaction force and all factors was established,and the response surface method was used to optimize the parameters.The results of the multi-factor tests showed that the optimal combination of cutting elements was the cutter speed of 200 r/min,cutting position of 17 mm,walking speed of 0.26 m/s,cutter overlap amount of 22 mm and pitch angle of 11°,and the maximum root cutting reaction force was-22.5 N at this time.Following the optimal combination of cutting elements,six validation tests were carried out with the qualified rate of root cutting as the performance index.The test results showed that the average value of the maximum root cutting reaction force was-21.8 N,and the average value of the qualified rate of root cutting was 96%.The adjustable test platform designed in this paper was reasonable and feasible,and could meet the basic requirements of root cutting operations.