Time filter

Source Type

Yuan J.,Shandong Agricultural University | Yuan J.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment | Liu X.,Shandong Agricultural University | Liu X.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment | And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

Air-assisted boom spraying has proven to have a positive effect on drift reduction. However, its effects with certain operational parameters of air-assisted boom sprayers are varied depending on natural wind speeds, outlet velocities of air curtain, spraying flow, spraying angle and etc, thus the spray drift rate and deposition rate are not stable in the field working. For example, if wind speed is low, and airflow and outlet speed of wind duct are high, which not only increases the power consumption of the fan, but also directly blew the droplets to ground and formed serious spray loss. On the contrary, when the wind speed is high, the speed of air-assisted flow is not enough to overcome the influence of wind, the spray droplets is drifted. To provide the control parameters to achieve precise control model with pesticide effect, this paper, leveraged by a three-dimensional multiphase flow computational fluid dynamics (CFD) model with the consideration of wind speeds, inlet speed of air curtain, spraying flow and spraying angle, simulates the coupling interaction of natural wind (continuous phase), the air curtain (continuous phase) and the droplets (discrete phase) of the air-assisted boom sprayer to study the droplet drift characteristics. The uniform experimental design took into the four factors with five levels of L2- deviation of the uniform design table U25 being applied to arrange the simulation scheme. Two criteria, the drift rate and the downward velocity under the duct 0.5m, were used to evaluate the spraying performance under the computing utilizing CFD simulation results. The simulation results were collected as training samples, and the multivariate relevance vector machine (MRVM) regression method was utilized to establish the 4-inputs-2-outputs spraying drift model accounting for the varying natural wind. The CFD simulation and the MRVM model only considered the four factors which influenced the spraying effect, however the vertical distance when the dense degree, crop of nozzle and the crop canopy were not at the same time, influence of spray effect was also affected by these parameters. Therefore, a fuzzy inference system model considersing crop canopy dense degree and vertical distance between nozzles and canopy was established to correct the 3 control parameters. According to the experiment, spray system analysis and expert experience, 11 fuzzy rules with Gauss membership function were set up. By using the fuzzy logic toolbox, fuzzy inference system was defined to obtain the mapping between input and output. In order to quantitative analysis the modeling quality of the droplet drift characteristics, the 3MQ-600 type air-assisted boom sprayer was used in the droplet drift test. Model tests showed that the mean absolute percentage error of the drift rate was 2.56%, and the spraying drift test of air-assisted boom sprayer prototype with natural wind disturbance had validated that the measured and predicted drift loss rate average error of 8.92%, which still showed the same interaction rule with the built spraying drift predictive model. This study provided the active control system with spraying ant-drift and droplet deposition effects-oriented control and decision-making model.


Yuan J.,Shandong University | Yuan J.,Shanghai JiaoTong University | Liu X.,Shandong University | Liu X.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment
Mechanical Systems and Signal Processing | Year: 2013

Supervised learning has been developed to collect condition monitoring (CM) data for fault diagnosis and prognosis. However, labeling the condition monitoring data is expensive due to the use of field knowledge while unlabeled CM data contain significant information of normal conditions or faults, which cannot be explored by supervised learning. Manifold regularization (MR) based semi-supervised learning (SSL) is first introduced to fault detection by utilizing both labeled and unlabeled CM data, and then a new single-conditions labeled mode based on MR is proposed for SSL learning. This approach, leveraged by effectively exploiting the embedded intrinsic geometric manifolds, outperforms supervised learning in both single-conditions labeled and all-conditions labeled modes within the application of two real-life fault detection datasets. The experimental results also suggest that most effective classifier in practical application could be trained by the SSL approach and fault type representation with medium load condition. The improved predictive performance implies that the manifold assumption of MR has its inherent fundamentals. Finally, the manifold fundamental of single-conditions labeled mode is analyzed with dimensionality reduction. © 2013 Elsevier Ltd.


Zhang W.,Shandong Agricultural University | Zhang W.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment | Lv Z.,Shandong Agricultural University | Lv Z.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment
International Agricultural Engineering Journal | Year: 2016

To improve vision guided lateral control of agricultural vehicle, a method based on adaptive neural fuzzy control system is proposed. Firstly vehicle lateral control model based on vision is established. Lateral deviation error and course error of preview point are set as the inputs of adaptive neural fuzzy control system respectively and front wheel angle is set as the output. Secondly after samples are collected in the actual driving experiment, adaptive neural fuzzy control system is established by training samples with "hybid" method. Finally simulation experiments are done using Matlab/Simulink and Carsim. Results showed that compared with the conventional fuzzy control system, the adaptive neural fuzzy control system can track reference path with different curvatures accurately; tracking performance and response time are greatly influenced by vehicle speed; in the snake path tracking experiment, the average error of path tracking is less than 0.1 m.


Fu G.-H.,Shandong Agricultural University | Liu X.-M.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment | Chen Y.-F.,Shandong Agricultural University | Yuan J.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment
Advances in Manufacturing | Year: 2015

According to the requirement of fast-growing forest pruning operation, the pruning robotwas developed.The structure and control system of pruning robot were described, the work flow of pruning robot was expounded. The type and structure of the drivingmotor and the compression springwere decided with force-balance analysis. The tilt problem of pruning robot was resolved by ADAMS and Matlab co-simulation, and the control scheme of climbing mechanism was determined. The experiment results of the prototype indicate that pruning robot can climb tree trunk smoothly at a speed of 20 mm/s and cross the raised trunk. The pruning saw which is driven by the adjustable speed motor can cut the branches of 30 mm. And the residual amount of branches is less than 5 mm. Pruning robot can meet the practical requirements of the fast-growing forest pruning work. © 2015, Shanghai University and Springer-Verlag Berlin Heidelberg.


Zuo W.L.,Shandong Agricultural University | Liu X.M.,Shandong Agricultural University | Yuan J.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment
Advanced Materials Research | Year: 2014

Natural wind, relative position between the nozzle and the outlet of the ram in the air-assistant spray have a great influence on performance. Air-assisted boom sprayer model is developed based on CFD. According to the data of the related parameters of the spray machine, variables of 3-D model were defined. With velocity of natural wind and inlet of the ram, the spraying flow keeping constant, the relative position between the nozzle and the outlet being a research variable, this article calculates the drift rate of the droplets respectively, then analyzes the results scientifically and gets the corresponding conclusion. At the same time, in order to confirm the reliability of the simulation results, this paper makes an experiment, which is done in Shandong agricultural university spray performance laboratory. Studies have shown that drift rate is significantly lower when the nozzles located under outlet position than on the downwind or the upwind. © (2014) Trans Tech Publications, Switzerland.


Fu G.H.,Shandong Agricultural University | Liu X.M.,Shandong Agricultural University | Yuan J.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment
Advanced Materials Research | Year: 2014

Tree-pruning robot can appear tilt problem in the climbing process because of the trunk shape and mechanical mechanism of its climbing legs. According to the robot's tilt problem, this paper guarantees the level of tree-pruning robot using the method of controlling the motor speed at different locations. This paper establishes a three-dimensional virtual prototype model about tree-pruning robot in ADAMS software, design controller in Matlab software, and conduct ADAMS-Matlab co-simulation. The simulation results and experimental prototypes show that the designed control method can effectively overcome the tilt problem in the crawling process. © (2014) Trans Tech Publications, Switzerland.


Li Y.,Shandong Agricultural University | Yuan J.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment
Advanced Materials Research | Year: 2014

In this paper, we discuss consensus problems for a network of dynamic agents with fixed topologies. A consensus algorithm for multi-agent systems with time-varying delay is presented. With the consideration of the effects of network conditions, such as network-induced delays, packet dropouts, mis-sequence, etc., a communication buffer is introduced for avoiding agents’ communication error, and a method for choosing buffer length is proposed. Using this buffer design, received data is rearranged and transferred in the original order. With the presented consensus algorithm, agents’ consensus is well-performance, and all the agents match the average speed finally. Simulation oriented results verify the effectiveness of the proposed algorithm. © (2014) Trans Tech Publications, Switzerland.


Yuan J.,Shandong Agricultural University | Yuan J.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment | Liu Q.,Shandong Agricultural University | Liu X.,Shandong Agricultural University | And 3 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2014

The blending process of granular multi-fertilizer flows in the nutrient proportion of variable rate technology (NPVRT) lacks mechanism research at present, and the blending cavity structure is the most important factor influencing blending uniformity of a variety of fertilizer. In this paper, using discrete element method, a variety of granular fertilizer, blending and seeding process based on three different blending cavity designs are simulated, and then the multi-fertilizers blending process and its uniformity characteristics are analyzed under three different structures. The computing results and mechanism analysis show that the collision wall shape of blending cavity affects rebound angle and horizontal velocity after particle collision, and both of factors affect the dispersed area of post-collision particles in the blending cavity. B type of blending cavity structure ensures optimum blending uniformity. When fertilizing flow increases, the fertilizer blending uniformity also increases accordingly.


Liu X.,Shandong Agricultural University | Liu X.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment | Yuan J.,Shandong Agricultural University | Yuan J.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

To reduce droplets drifting and improve the droplets penetration and utilization, 3MQ-600 type air-assisted boom sprayer with air-deflector was designed. Hydraulic motor, axial fan, diaphragm pump and other components were driven by tractor and hydraulic pumps. The new grid-like deflector was installed in the air duct, and the flow structure inside the duct was optimized. Experimental results showed that, compared with no wind screen spraying, the average number of droplets increased by 29.5% and the coefficient of variation decreased by 78.5% along the boom in the uniformity of spraying volume, and droplets drift decreased by 45%, and droplet deposition in the middle and bottom parts of crops reaches 50.8% in the crop canopy droplet penetrability. The machine has high performance and reduces drift droplet deposition performance, better utilization of pesticides.


Li C.,Shandong Agricultural University | Li C.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment | Zhang X.,Shandong Agricultural University | Zhang X.,Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

For avoiding pesticide waste due to uneven spraying volume distribution of the traditional axial mist sprayer, riser air-blowing vineyard sprayer was developed which took small four-wheel tractors as power. Through the variable power takeoff installed in the left of the speed change box in tractor, the riser air-blowing vineyard sprayer transferred the power from tractor to rear plunger pump and centrifugal blower. When the airflow blown by the centrifugal blower was blown through air outlet of wind-cone installed both sides of the vertical spray rack, it can not only prevent the droplet drifting, but also atomize the droplet and increase the penetration of the droplet in the grapes. Because of different vineyard row distances, adjustable spray frame structure was designed. It is connected by three segments of square steel tubes which was adjustable and had a series of holes. Through the adjustable spray frame structure, the spray distance of sprayer was from 800 mm to 1600 mm. The indoor and field experiments of prototype were done to test the anti-floating performance, secondary atomization performance of vertical wind-cane structure and adhesive rate of droplet in crown. The experimental results indicated that when the natural wind speed was 3.5 to 4.5 m/s and the air speed of duct outlet was 30 and 35 m/s, the pesticide drift was reduced, the deposition were increased, the volume median diameter(VMD)of the droplets were less than 150μm, the diffusion ratio(DR)of the droplets was more than 0.74, and the secondary atomization performance was better. The droplet adhesion rate in leaves on positive and negative sides inside the trees reached 70.22% and 30.21% respectively, and that on leaves of positive and negative sides outside the trees reached 85.69% and 49.36% respectively when the distance between the nozzle and the tree was 30 cm, the speed of the tractor was 1.5 m/s, the pressure of plunger pump for sprayer was 0.25 MPa, the speed of the fan was 2 500 r/min. These parameters meet the requirement.

Loading Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment collaborators
Loading Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment collaborators