Accurate measurement of the downwash flow field of plant protection unmanned aerial vehicles (UAVs) is essential for analyzing the spatial distribution of droplets. To realize on-line rapid detection of the downwash flow field of a multi-rotor UAV, a flexible polypropylene detection device based on the principle of full bridge strain effect was proposed. Its performance principle was based on the physical deformation caused by wind pressure. The Fluid Flow and Static Structural modules of ANSYS 16.0 finite element software were used to simulate one-way fluid-solid coupling interaction. The surface of the resistive strain gauge embedded in the flexible detecting structure responded well to wind speed variation, hence it was suitable for downwash airflow wind field detection. By solving the strain force on the surface of the flexible detection structure, the length and layout of the grating wire of the strain gauge on the surface of the flexible detection structure were optimized. Meanwhile at 4 m·s-1 wind speed, the output voltage at varied bridge flexible acquisition systems in the acquisition card was measured. Results indicated coefficient of variation of 3.67%, 1.63% and 1.5%, respectively, which proved the good data acquisition consistency of the system. Through calibration test, the regression equation for the relationship between output voltage and wind speed for three unique sensor signal measuring circuits was established. The determination coefficients R2 for single bridge, half bridge and full bridge circuits were 0.9885, 0.9866 and 0.9959, respectively. In conclusion, by applying the multi-rotor plant protection UAV test platform, the results indicated the maximum relative error of the wind speed at each sampling point of the system at 1.0 m altitude was below 5.61%. Simulated and measured value had an RMSE maximum error of 0.1246 m·s-1. Moreover, downwash airflow detection not only has high accuracy but also has high sensitivity. Thus, there is convenience and practicability in the plant protection offered by this approach. The rapid measurement of UAV wind field and the established two-dimensional wind field model can provide a basis for precise application of agricultural aviation.

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Design of UAV Downwash Airflow Field Detection System Based on Strain Effect Principle

Uniform seed distribution within the row is the prime objective of precision planters for better crop growth and yield. Inclined plate planters are generally used for sowing bold seeds like maize, groundnut, chickpea, and their operating parameters like the forward speed of operation, the seed metering plate inclination, and the seed level in the hopper affect the cell fill and subsequently the uniform seed distribution. Therefore, to achieve precise seed distribution, these parameters need to be optimized. In the present study, out of the different optimization techniques, a new intelligent optimization technique based on the integrated ANN-PSO approach has been used to achieve the set goal. A 3–5-1 artificial neural network (ANN) model was developed for predicting the cell fill of inclined plate seed metering device, and the particle swarm optimization (PSO) algorithm was applied to obtain the optimum values of the operating parameters corresponding to 100% cell fill. The most appropriate optimal values of the forward speed of operation, the seed metering plate inclination, and the seed level in the hopper for achieving 100% cell fill were found to be 3 km/h, 50-degree, and 75% of total height, respectively. The proposed integrated ANN-PSO approach was capable of predicting the optimal values of operating parameters with a maximum deviation of 2% compared to the experimental results, thus confirmed the reliability of the proposed optimization technique.

Optimizing the seed-cell filling performance of an inclined plate seed metering device using integrated ANN-PSO approach

Research on the constitutive model of low-damage corn threshing based on DEM

A wedge-shaped no-tillage opener consisting of sharp front knife edge and pedestal with lateral wings has been designed. The front knife is connected with the pedestal by means of inner bolts and can be conveniently changed when it is abraded.Tests of resistance and power consumption are carried out in the field covered with maize straw.Test results show that the wedged-shaped no-tillage opener can reduce the surface soil disturbance to between 15% and 25%,and reduce the straw coverage rate by 10%～20%, so it can satisfy the requirement of no-tillage sowing.In comparison to the tine opener,it has the advantages that the soil bulk density is decreased significantly,the resistance and the fuel consumption are reduced by 13.2% and 15% separately when the depth of furrow opening is 10 cm,thus reducing the power consumption of tractor.So the wedged-shaped no-tillage opener solves the problem of high resistance and power consumption when the depth of furrow opening is 10 cm,and creates the loose seedbed,and which has important significance to the popularization and application of no-tillage seeders in China.

Design and Experiment on a Wedge Shaped No-tillage Opener

Полезная модель относится к сельскому хозяйству. Комбинированный почвообрабатывающий агрегат включает раму, на которой смонтированы вертикальные стойки с осями и установленные на осях с возможностью вращения сферические диски, имеющие регулируемый угол атаки, глубокорыхлители, сзади агрегата установлены транспортно-технологические колеса. По периферии каждого сферического диска выполнены выемки в виде полукруга, а режущая кромка сферических дисков заточена. С задней частью рамы агрегата закреплена катковая приставка, содержащая последовательно установленные катки рыхлительного и выравнивающего типа, Н-образную раму, кронштейны и штанги. На каждой штанге установлены гайки и пружина. Каток рыхлительного типа содержит ось и дисковые рыхлители, установленные на оси катка рыхлительного типа через равные интервалы в горизонтальной плоскости. По периферии дисковых рыхлителей выполнены треугольные выемки. Вершины, расположенные между треугольными выемками, также выполнены треугольными и двусторонне заточенными и направленными в разные стороны от геометрической оси вращения дисковых рыхлителей. Каток выравнивающего типа содержит ось, боковые и промежуточные диски, установленные на оси через равные интервалы в горизонтальной плоскости. По периферии боковых и промежуточных дисков выполнены треугольные выемки. В треугольных выемках боковых и промежуточных дисков и установлены рыхлители таким образом, что они образуют винтовую линию. Направление винтовой линии выравнивающего катка начинается от его продольной оси симметрии и направлено в сторону боковых дисков. Рыхлители в поперечном сечении выполнены квадратными и скрученными по всей длине на угол α относительно своей продольной оси симметрии таким образом, что острые кромки каждого рыхлителя образуют винтовые линии. Острые грани рыхлителей направлены в разные стороны от геометрической оси вращения выравнивающего катка. Обеспечивается повышение качества обработки почвы. 4 ил.

Комбинированный почвообрабатывающий агрегат

Spraying strategy optimization with genetic algorithm for autonomous air-assisted sprayer in Chinese heliogreenhouses

Design and experiment of adjustment device based on machine vision for garlic clove direction

The utility model relates to a small -size chinese cabbage harvester, including the beam rack, horizontal beam arm, hand device, clamping device, guider, cutting device, transmission system. The beam rack is used for fixed power device and horizontal beam arm, the interval that horizontal beam arm is used for fixed clamping device frame, land wheel and adjusts two centre gripping belts to the different chinese cabbage variety of adaptation, guider is used for direction and leaf dish to draw in in, cutting device is used for cutting the root of chinese cabbage, transmission system is used for the power transmission of complete machine. The utility model discloses nimble to the adjustment of the chinese cabbage of different cultivars results, adaptability is good, gather in the crops efficient, better to the protection of chinese cabbage at the results in -process, very big reduction the breakage rate, machine construction is simple, and is easy and simple to handle, is fit for the chinese cabbage results operation use that the small size was planted.

Small -size chinese cabbage harvester

Burgers viscoelastic model-based variable stiffness design of compliant clamping mechanism for leafy greens harvesting

Variable transmission ratio racks show great potential in rice transplanters as a key component of variable transmission ratio steering to balance steering portability and sensitivity. The objective of this study was to develop a novel geometrical design method to achieve quick, high-quality modeling of the free curvilinear tooth profile of a variable transmission ratio rack. First, a discrete envelope motion 3D model was established between the pinion-sector and the variable transmission ratio rack blank based on the mapping relationship between the rotation angle of the pinion-sector and the displacement of the rack, according to the variable transmission ratio function. Based on the loop Boolean subtraction operation, which removed the pinion-sector from the rack blank during all moments of the discrete motion process, the final complex changing tooth shape of the variable transmission ratio rack was enveloped. Then, since Boolean cutting residues made the variable ratio tooth surface fluctuant and eventually affected the precision of the model, this study proposed a modification method for establishing a smooth and continuous tooth profile. First, a novel fitting algorithm used approximate variable ratio tooth profile points extracted from the Boolean cutting marks and generated a series of variable ratio tooth profiles by utilizing B-spline with different orders. Next, based on a transmission stability simulation, the variable ratio tooth profile with optimal dynamic performance was selected as the final design. Finally, tests contrasting the transmission stability of the machining samples of the initial variable ratio tooth profile and the final variable ratio tooth profile were conducted. The results indicated that the final variable ratio tooth profile is more effective than the initial variable ratio tooth profile. Therefore, the proposed variable ratio tooth profile modeling and modification method for eliminating Boolean cutting residues and improving surface accuracy is proved to be feasible.
Keywords: rice transplanter, steering, variable ratio tooth profile, variable ratio curve, Boolean subtraction operation, transmission stability
DOI: 10.25165/j.ijabe.20201305.4884

Citation: Niu Z R, Li J L, Xin S, Zou L L, Li Y H, Hou J L, et al. Geometrical design of variable ratio tooth profile based on Boolean subtraction operation and a novel modification method. Int J Agric & Biol Eng, 2020; 13(5): 125–133.

Niu Ziru

Papers

Spraying strategy optimization with genetic algorithm for autonomous air-assisted sprayer in Chinese heliogreenhouses

Design and experiment of adjustment device based on machine vision for garlic clove direction

Small -size chinese cabbage harvester

Burgers viscoelastic model-based variable stiffness design of compliant clamping mechanism for leafy greens harvesting

Geometrical design of variable ratio tooth profile based on Boolean subtraction operation and a novel modification method