Jiangsu Key Laboratory for Intelligent Agricultural Equipment

Nanjing, China

Jiangsu Key Laboratory for Intelligent Agricultural Equipment

Nanjing, China

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Zhao J.-K.,Nanjing Agricultural University | Zhao J.-K.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment | Wang D.,Nanjing Agricultural University | Huang S.-J.,Nanjing Agricultural University
Dongbei Daxue Xuebao/Journal of Northeastern University | Year: 2015

The constitutive model of particles connected damage was derived on the basis of the discrete element method (DEM), and the three dimensional steep rock model was established to simulate the rock progressive failure evolution process. Related mechanical and motion parameters at 9 test points in the model were tracked in real time to analyze the evolution of the parameters with the model from the stable to the slide, and even gravel movement. The results showed that the difference of nonlinear motion characteristics is obvious from the adhesive to the damage fracture and then to movement of the meso-particles. Under horizontal earthquake, the progressive failure of rock mass is serious on the left side, which presents a fracture-separation-contact collision-and then separate motion evolution. Under different seismic intensity, there is obvious difference in damage of rock mass, and rock mass is severely damaged under the seismic amplitude of above 15.0. Under the seismic p-wave alone, the rock mass remains integrated though horizontal cracks and large deformation in the middle occur. Seismic shear wave is the main factor of rock mass damage, under the action of the longitudinal wave and transverse wave superposition, the rock mass damage is serious on both sides. ©, 2015, Northeastern University. All right reserved.


Wang Y.,Nanjing Agricultural University | Kang M.,Nanjing Agricultural University | Kang M.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2014

In order to shorten the preparation period of anode nozzle, a mathematical model of the liquid field in machining area was built according to liquid turbulent flow, and a mathematical model of secondary electrodeposition was built according to electrodeposition with moving geometry. The boundary conditions were chosen according to the parameters of the jet-electrodeposition experiments. Software, COMSOL Multiphysics was used to simulate the machining area. The influences of liquid field and electric field distribution on machining precision were analyzed, and the profile curves of cathode growth at different times were simulated. And then the nice solution of anode nozzle was determined. It is demonstrated that the bottom of an arc-shaped anode nozzle will be the better to machining. The simulation results are in agreement with that of the experiments.


Wang X.,Nanjing Agricultural University | Kang M.,Nanjing Agricultural University | Kang M.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment | Fu X.,Nanjing Agricultural University | Li C.,Nanjing Agricultural University
International Journal of Advanced Manufacturing Technology | Year: 2013

Slow tool servo (STS) turning is superior in machining precision and in complicated surface. However, STS turning is a complex process in which many variables can affect the desired results. This paper focuses on surface roughness prediction in lenses STS turning. An exponential model, based on the five main cutting parameters including tool nose radius, feed rate, depth of cut, C-axis speed, and discretization angle, for surface roughness prediction of lenses is developed by means of orthogonal experiment regression analysis. Meanwhile, a prediction model of surface roughness based on least squares support vector machines (LS-SVM) with radial basis function is constructed. Orthogonal experiment swatches are studied, and chaotic particle swarm optimization and leave-one-out cross-validation are applied to determine the model parameters. The comparison of LS-SVM model and exponential model is also carried out. Predictive LS-SVM model is found to be capable of better predictions for surface roughness and has absolute fraction of variance R2 of 0.99887, the mean absolute percent error eM of 8.96 %, and the root mean square error eR of 10.68 %. The experimental results and prediction of LS-SVM model show that effects of tool nose radius and feed rate are more significant than that of depth of cut on surface roughness of lenses turning. © 2013 Springer-Verlag London.


Yu M.,Nanjing Agricultural University | Yu M.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment | He C.,Nanjing Agricultural University | He C.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment | And 6 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

In order to improve the interfacial bonding strength of wheat straw fibers and polypropylene (PP), the wheat straw fibers were treated by combined treatment. The surfaces of fibers were pretreated by 5 methods, such as NaOH, acetic acid, hot water, steam explosion and microwave, and then compounded by coupling agent treatment. The wheat straw/PP wood-plastic composites were prepared by blending with PP and wheat straw through melt blending and molding. The mechanical properties, water absorption and moisture absorption performance of the PP wood-plastic composites filled with different surface treated wheat straw fibers were investigated. The tensile sections of the composites were observed by the stereo microscope. The results showed that the mechanical properties, water absorption and moisture absorption performance of PP composites filled with combined treated fibers were excellent that the composites filled with coupling agent treated fibers. It was found that the composites with wheat straw treated by NaOH and acetic acid had good mechanical properties and anti-water absorption and anti-moisture absorption performance, followed by the composites with wheat straw fibers treated by hydrothermal and steam explosion. After combined treatment, the surface of wheat straw became rough, so that the interfacial adhesion of straw fibers and PP matrix was improved. The results of this paper had great practical significance on improving the properties of wheat straw/waste PP wood-plastic composite by straw fiber surface treatment.


Liu W.,Nanjing Agricultural University | Liu W.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment | Wang X.,Nanjing Agricultural University | Wang X.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

In order to realize variable-rate spraying of knapsack sprayer, frequency of 8 kHz square wave and adjustable duty ratio were evaluated to control micro electric diaphragm pump. By changing the on and off time of DC Motor, the application rates of knapsack sprayer based on the PWM could be controlled, and the spray characteristics were analyzed also. Results showed that the volume of spraying increased with increasing of the duty ratio, but the rate of volume decreased gradually, and the maximum and minimum volumes of spraying were 1.13 and 0.66 L/min respectively. With the increase of duty ratio and spraying volume, spraying area spread to both sides and the spray angle increased gently, and the lowest and the highest value were 41.53° and 61.78° respectively. The diameter of spray droplets were between 100 and 135 μm, and decreased with increasing of duty ratio. The droplets velocity increased with increasing of the duty ratio, and the velocity in the middle was higher than that in both sides obviously. The variable-rate spraying control system is stable which can be effectively applied to agricultural production.


Sun G.,Nanjing Agricultural University | Sun G.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment | Wang X.,Nanjing Agricultural University | Wang X.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

In order to analyze the effect on the droplet drifting made by the airflow, the discrete phase particle tracking technology was used to get the characteristics of the droplet deposition in different spraying conditions, based on the CFD theory. The virtual cube was in the dimension of 3 m×2 m×2 m with a sprayer nozzle at the top( the geometrical center of abaxial surface for cube). The characteristics of droplet deposition were simulated with the optimized boundary conditions at the different height of deposition, ranging from 0.25 to 2 m, and at the different speed of the wind, from 0 to 3 m/s. The results showed that the distribution of the droplets were different at the different speed of the wind. The droplet deposition decreased when both the height of the droplet section and the speed of the wind increased, of which the maximum was 100%(at the height of 0.25 m and the speed of 0), and the minimum was 7.2%(at the height of 2 m and the speed of 3 m/s). The maximum and minimum of droplet deposition ratio was 79.07%, 3.98%, respectively, and prediction models of the droplet deposition and the droplet ratio were established based on technology mentioned in this paper, which provides a reference for precise pesticide application.


Wang Y.,Nanjing Agricultural University | Kang M.,Nanjing Agricultural University | Kang M.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment | Chen C.,Nanjing Agricultural University | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

The cylinder is an extremely important easily wearing part of a tractor engine, whose service life and production cost are directly affected by the wear resistance of the component. With excellent wear resistance, corrosion resistance, and greater hardness, a Ni-P alloy deposited layer can significantly enhance the service life and reliability of the cylinder, and the capability and quality of the tractor engine can be improved. The lower limiting current density of the traditional electrodeposited Ni-P alloy method leads to a lower depositing rate and lower production efficiency. Jet electrodeposition has been developed in recent years, which can significant increase the depositing rate because the jet electrolyte can accelerate the transfer process of the electrodeposition material and augment limiting current density. So jet electrodeposition is a type of high-velocity, selective electrodeposition technique with high deposition current density and high velocity. Furthermore, optimization of the process parameters of jet electrodeposition is the way to further increase the depositing rate. In this paper, technological experimentation is investigated by using a custom design of JMP to optimize process parameters of jet electrodeposition. The JMP software is Six Sigma statistical software developed by SAS, which is a professional statistical analysis tool. The JMP software can be used for processing data and designing of experiments. To the best of our knowledge, there is currently no report about applications of JMP in electrochemical use domestically. Voltage, electrolyte temperature, dipolar space, flow velocity of electrolyte, and dipolar relative velocity are the influence factors, and the depositing rate of deposited layers is the experimental index, and the relationships between the experimental index and the influence factors are analyzed through the response surface analysis method and sub-stepping method. The quadratic regression mathematical models that described the relations between the experimental index and the influence factors were established. The optimal technological parameters for depositing rate of a deposited layer were obtained through conducting a multivariable function optimization by the method of a quadric spindle gradient. The results suggest that JMP software can obtain more accurate optimal values by calculating than by orthogonal test. Voltage, electrolyte temperature, dipolar space, and dipolar relative velocity affect the depositing rate of a deposited layer markedly. The quadratic term of dipolar space have a high-impact on the surface effect of the depositing rate. And furthermore, voltage and flow velocity of the electrolyte, electrolyte temperature and flow velocity of electrolyte, flow velocity of electrolyte, and dipolar relative velocity have interactive effects on the changes of the depositing rate. The quadratic regression mathematical models reach a significant level and the equation has good fitting effects. So the models can be applied to predict the depositing rate of a deposited layer. The response surface methodology obtained the influences of voltage, electrolyte temperature, dipolar space, flow velocity of the electrolyte, and dipolar relative velocity on depositing rate of a deposited layer. And the optimal parameters are as follow: voltage of 15V, electrolyte temperature of 72°C, dipolar space of 1mm, flow velocity of electrolyte of 1.2 m/s, and dipolar relative velocity of 170 mm/min. Under these conditions, the depositing rate of a deposited layer is 79.13 μm/min and the quality of the deposited layer is better. The depositing rate of jet electrodeposition is about 130 times that of a traditional electrodeposition, and use of jet electrodeposition improves production efficiency. It can help to promote the development of high-speed plating.


Wang G.,Nanjing Agricultural University | Wang G.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment | Zhu S.,Nanjing Agricultural University | Shi L.,Nanjing Agricultural University | And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

In order to improve the power shift quality of agricultural tractors with continuously variable transmission, the power shift process of a new kind of tractor hydraulic mechanical CVT was studied. Based on bench tests of the power-shift of the CVT and a homemade control system, we conducted a suite of experiments on the oil charge of the clutches, transmission load with single and multiple factors, and shift timing optimization. During the experiments on the oil charge of the clutches, the engine was turned off, and the relationships between the shift time and the oil pressure of the hydraulic system and the flow rate of the clutch were revealed. During the load experiments with single and multiple factors, the relationship between the shift quality and the rotation speed of the engine, the oil pressure of the hydraulic system, the flow rate of the clutch, and the load torque were revealed. During the experiments on shift timing optimization, the optimized connection time of the clutch was studied. The results show that the shift quality is influenced by the oil pressure of the hydraulic system and the flow rate of the clutch, which would change the shift time. The pressure changing rule of the clutches during the shift process was revealed and proved the overlapping shift to be safe and feasible. The shift experiments with a single factor show that the shift quality is positively related to the flow rate of the clutch and the oil pressure of the hydraulic system, but inversely related to the load torque. There is no significant relation between the shift quality and the engine speed. The shift experiments with multiple factors show that the significance of the factors affecting speed drop and speed impact are the flow rate of the clutch, the load torque, the oil pressure of the hydraulic system, and the engine speed. The significance of the factors affecting the dynamic load are the load torque, the flow rate of the clutch (which is in parallel with the oil pressure of the hydraulic system), and the engine speed. In addition, the overlapping shift would evidently improve the shift quality. According to the experiment results, the optimal flow rate of the clutch is 5 L per minute, the optimal oil pressure of the hydraulic system is 4 Mpa, and the optimal shift timing is 120 ms, i.e. one clutch should be energized 120 ms ahead of the other. The conclusion provides an important reference for the design of transmission control units.


Wang G.,Nanjing Agricultural University | Wang G.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment | Zhu S.,Nanjing Agricultural University | Wang S.,Nanjing Agricultural University | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

This paper studied the speed ratio control problem of the hydraulic mechanical continuously variable transmission. First, based on the speed ratio characteristics of the transmission and the experiment on the identification of the hydraulic system, the steady-state and dynamic mathematical model among the excitation current of the variable displacement pump, the speed ratio of the pump-motor system and the speed ratio of the transmission were built. It showed that the speed ratio of the transmission is a segmented function of the speed ratio of pump-motor system. The relationship between the excitation current of the variable displacement pump and the speed ratio of pump-motor can be considered as a third-order system. According to this model, a neural PID controller based on single neuron network was developed. A set of feasible parameters, i.e. the inertia coeffecient k and the learning coeffecient ηP, ηI, ηD of the PID controller can be determined according to the tuning law which have been studied based on the simulation and experiment. From that, it showed that an appropriate k, ηP, a larger ηI and a smaller ηD can meet a satisfactory internal-stage control quality. Secondly, the open-loop and closed-loop control mode defined by a relay logic was proposed in this paper, so as to make the neural PID controller work at specific intervals and conditions and effectively avoid the frequently power-shift and direction-changed of motor rotation. The controller calculates the target stage and direction of motor rotation according to the target speed ratio of transmission. Once the current stage and direction of motor rotation are different from the target, the power-shift logic and the displacement adjustment logic of the pump can be actived by the open-loop controller to reach the target states following the stepless speed changing rule, otherwise, the closed-loop controller would adjust the speed ratio of the transmission to the target without power-shift and direction-changed of motor rotation based on the neural PID technology. Finally, an experiment of speed ratio control was conducted. During the experiment, it took 5-6 s to hold one direction of motor rotation when the open-loop controller worked, the process under the speed ratio control was smooth and steady and no steady-state error was there at the end of the experiment, the results proved the algorithm to be correct and feasible.


Wang X.,Nanjing Agricultural University | Fu X.,Nanjing Agricultural University | Li C.,Nanjing Agricultural University | Kang M.,Nanjing Agricultural University | Kang M.,Jiangsu Key Laboratory for Intelligent Agricultural Equipment
International Journal of Advanced Manufacturing Technology | Year: 2015

Slow tool servo (STS) turning is a superior process for machining precision and complicated surfaces that has already gained a wide application especially in optics industry. However, it is lack of systematically study of tool path generation for STS turning of complex surfaces, especially of interpolation among discrete cutting location points. This paper presents a comprehensive tool path generation strategy for STS turning of complex surfaces, including cutting location point optimized planning, trajectory interpolation, and machining simulation. First, cutting contact point discretization and tool geometry compensation were analyzed during cutting location point planning procedure. Second, Hermite segment interpolation used by trajectory interpolation was analyzed, and three position-velocity-time (PVT) entrance parameters algorithms were put forward, i.e., the constant speed method, area method, and the three points method. Third, the machining simulation was carried out to evaluate the performance of the generated tool path. The analysis of Z-axis motion characteristics indicated that both the area method (c = 2/3) and three points method can meet the requirements of smooth velocity of Z-axis when the Z-axis reciprocating frequency is similar to the C-axis rotating frequency. From the viewpoint of acceleration, the three points method is much better than the area method when the Z-axis reciprocating frequency is significantly greater than the C-axis rotary frequency. Finally, a progressive addition lens surface was fabricated to prove the feasibility of the proposed tool path generation method. © 2015, Springer-Verlag London.

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