Design And Test Of Automatic Parallel Measurement And Control System For Leaf Vegetable Orderly Harvester

In recent years,with the maturity and application of facility vegetable technology,the planting area and yield of vegetables in China have increased year by year,but the automation level of harvesting links is seriously lagging behind food.Confrontation operation is a very important link in the orderly harvesting of leafy vegetables.Only relying on manual implementation,the driver ’ s driving technology requirements are high and easy to fatigue,and the quality of the line is low.The non-automatic row-torow harvest will affect the harvest quality of leaf vegetables,reduce the harvest efficiency,and cause leakage cutting.Therefore,it is necessary to develop the parallel detection mechanism and automatic parallel control system for the orderly harvesting of leafy vegetables.Based on the demand of automatic alignment of leafy vegetables orderly harvester,this paper designs an automatic alignment measurement and control system for leafy vegetables orderly harvester.The main research contents are as follows :(1)Taking Suzhouqing as the research object,the plant height,leaf expansion and stem diameter of Suzhouqing during harvest were tested and statistically analyzed.The force offset characteristics of Suzhouqing at different heights were measured by digital push-pull meter,and the offset distance of Suzhouqing relative to the baseline under growth condition was statistically analyzed.The maximum offset distance can reach 6 cm.The fitting analysis of height from root and stem diameter of Suzhouqing showed that the slope of 60-day growth curve was 0.495,the fitting degree R2 was0.981,the slope of 40-day growth curve was 0.368,and the fitting degree R2 was 0.916.The above data can provide reference for the design of key components of automatic alignment detection device and the optimization of line program.(2)Aiming at the shortcomings of traditional mechanical sensing device,a new mechanical parallel detection device is designed.The key components of the detection device are designed and calculated,and the angle sensor is selected.A ground wheel speed detection device is designed to detect the working speed of the harvester.Through the design and selection,the alignment,forward speed,heading angle and front wheel angle detection system are formed.(3)In order to realize the accurate control of the operation direction in the harvesting operation,the automatic alignment control model of leafy vegetable harvester was studied,and the pure tracking model based on the two-wheel vehicle model of leafy vegetable orderly harvester was established.The fuzzy control algorithm was used to dynamically control the forward-looking distance of the harvester.The PID control system based on electric power steering is designed.The three control parameters of PID are KP = 2.05,KI = 0.025,KD = 0.Single chip microcomputer is selected as the control module of the system.(4)The automatic line-to-line measurement and control system was built and related experiments were carried out.The test results show that when there is no ridge fluctuation,the velocity increases and the measured offset increases,but the maximum increase is ≤ 0.155 cm,which has little effect and can be ignored.When the fluctuation is 0,1,2 and 3 cm,the corresponding average migration distances are 0.12,0.16,0.16 and 0.18 cm,respectively,within the allowable range.Three-factor tests of velocity,offset distance and leaf-vegetable spacing were conducted.The detection accuracy at 0.08,0.12 and 0.16 m / s was 98.58 %,96.32 % and 93.34 %,respectively.When the offset distance is 30 mm,the detection accuracy of 50 mm is 88.2 % and 94.36 %respectively.The detection accuracy is 87.77 %,91 % and 91.43 % respectively at 50,80 and 100 mm spacing.When the operating speed was 0.08 m / s,0.12 m / s and 0.16 m / s,the average errors were 10.7 mm,12.8 mm and 17.3 mm,respectively.The test results show that the alignment error increases with the increase of speed,but it can generally meet the alignment requirements of leaf vegetables ordered harvester.Aiming at the problem of automatic alignment of leafy vegetables orderly harvester,this paper designs the relevant automatic alignment detection device and control system,realizes the automatic alignment of leafy vegetables orderly harvester,and provides technical support for low loss and efficient orderly harvesting of leafy vegetables.