Abstract:Two types of suspension with inerters were designed. The mathematical model of suspension with inerters was built. The suspension with inerters ofⅠandⅡtypes were set up. With the multi-objective optimization methods, the performance parameters of the two types were obtained. Based on the simulation, the bench test was done and the simulation was consistent with the test results. It shows that the suspension with inerters exerts the feature that spring was phase leg, damper was neutral and inerters was phase advance. The vehicle vibration isolation performance was increased and the comprehensive performance of vehicle was coordinated.

Abstract:Considered the front alignment, a 4-DOF vehicle shimmy model with independent suspension was established by Lagrange equation. The numerical analysis for the speed range of multiple limit cycles and numerical characteristics was performed with respect to the change of the caster angle. It showed that the speed range of multiple limit cycles was advanced. The amplitude of unstable limit cycles was reduced. The amplitude of stable limit cycles was enlarged and the frequency didn’t change with increasing caster angle. The paper result was helpful to provide theoretical reference for reducing vehicle shimmy and controlling of multiple limit cycles.

Abstract:A half-car model of semi-active suspension systems with 4-DOF was established. An innovative fuzzy hybrid control strategy considering both ride quality and road-friendliness was developed. For deeply verifying the application of the proposed control strategy in real vehicles, a platform of hardware-in-the-loop was built for evaluating the proposed control strategy of semi-active suspension systems using a self-designed electronic control unit based on Freescale MC9S12XDP512 microcontroller and Matlab/Real-time Windows Target toolbox. A series of hardware-in-the-loop simulation were conducted by using the platform. It showed that compared with skyhook control strategy and groundhook control strategy, HIL-based fuzzy hybrid control strategy can make a balance between vehicle ride and road-friendly and had the application feasibility.

Abstract:A mathematical model of 3-D random road surface was established based on the basic principles of harmonic superposition and triangulated irregular network. A rigid flexible coupling multi-body dynamic model of a heavy truck was established by using SIMPACK software, which included front suspension, rear balance suspension, steering system, tire system, etc. The tires and leaf springs were treated as deformable body, and rubber pads and limit block were reduced to force elements with non-linear stiffness and damping characteristics. Then a ride dynamic model of heavy vehicle was established，which combined virtual prototype vehicle with 3-D random road surface model by using SIMPACK software. The dynamic load coefficient and 95 percentage fourth power aggregate forces were used as the road-friendliness criterions for analyzing the road friendliness of heavy vehicles with different speed. Simulation results indicated that, when the vehicle drove on the B- and C-grade 3-D random road at the speed of 60~90km/h, the road friendliness of mid-axle and rear-axle reduced as the vehicle speed increased. The road friendliness of front-axle didn’t increase as the vehicle speed increased. When the vehicle speed surpassed 80km/h, the road friendliness of front-axle began to decrease. The road friendliness of the vehicle reduced as the vehicle speed increased. The road friendliness of B-grade road reduced by a big margin, while the road friendliness of C-grade road reduced by a small margin.

Abstract:A state estimation method for 4WD vehicle was demonstrated by measuring lateral tire forces and longitudinal tire forces. Based on 3-DOF vehicle model, a state observer was realized using extended Kalman filter technique. The observer provided several advantages that the vehicle velocity and sideslip angle estimates could be robust with variance of wheel slip ratio and road friction under extreme adherence condition, such as split friction road. The paper demonstrated the appropriateness of this observer by slalom simulation test using veDYNA software. Simulation results were compared with traditional nonlinear state observer. The comparisons indicated that the longitudinal velocity and sideslip angle estimates of proposed observer both approached the true value very well. The maximum errors were no more 0.6km/h and 0.2°, comparing to 25km/h and 3° of the maximum errors of traditional nonlinear state observer. The proposed estimation method was an effective self-adaptation approach to wheel slip ratio and road friction condition. 

Abstract:The matching analysis was carried out between automatic transmission (AT) and the friction characteristics of automatic transmission fluid (ATF). The evaluation indexes of shifting elements in AT and the key characteristics of ATF which influenced the evaluation indexes of shifting elements in AT were confirmed. The dynamical model and the dynamic simulation model were built. The calculation and simulation analysis were done for torque capacity, power density, and friction work. The matching requirements between the shifting elements in AT and the friction characteristics of ATF could be obtained. The feasibility, correctness and effectiveness of the method could be proved. 

Abstract:To improve damping force and reduce response time of magnetorheological (MR) damper, an optimal structure designing method was presented. The structure optimal methods, including reverse series of excitation coils and composed permanent magnets piston structure, was based on the calculation of resultant magnetic field for different excitation coil winding approachs. According to the provided structure optimal method, a MR damper was manufactured and its mechanical performances were tested on type DS-100 fatigue-testing machine with different forcing vibration frequency, vibration amplitude and control current. The experiments showed that the damping force of the proposed MR increased by 65%, and the response time reduces to more than a half at the most. This result provided an important reference to further mechanical property improvement of MR damper.

Abstract:In order to control excavator automatically, an excavator was retrofitted with electro-hydraulic proportional control systems. Kinematic models for excavator’s mechanism and nonlinear model for its electro-hydraulic system was established respectively. The dead-band and asymmetry nonlinearities of the electro-hydraulic system which was deduced in the theory models was demonstrated by experiments. To satisfy ground-leveling task, a 5-order polynomial was used for path generation in Cartesian space, and the joint-space path was calculated by kinematic models. According to the dead-band and asymmetry nonlinearities of control system, a segment PID controller with dead-band compensation was designed. Comparison experiments demonstrated that segment PID overcame the majority nonlinearities effectively. It had better tracking performance than conventional PID. In conclusion, complex path tracking was achieved by coordinated control of the three working arms. 

Abstract:The differences of corn planting-harvesting process and harvesting equipment between China and developed countries, corn harvester developing process and major model were introduced. The general technology and equipment of snapping, husking and straw treatment of corn harvesting machine, and the research and exploration of corn harvesting technology regardless of row in China were expatiated. The major factor for restricting development of corn harvest mechanization in China, the development trend of foreign corn harvester, and planting and harvesting characteristics of Chinese corn producing areas were analyzed. Finally, it pointed out that the corn harvester should be designed with combination of agricultural machinery and technology to suit local condition in China.

Abstract:2BMQ-180/3 type no-tillage maize planter with stalk mulch smashing and fertilizing was developed. The anti-blockage measures when using the smashing straw endings machine-driven by vertical shaft rotary to smash the straw and weeds and throw them on the surface of the fields before the opener to plough the ditch was put forward. Then, the machine’s work performance was tested. The results showed that the planter performed very well. Its variation coefficients of sowing fertilizer cover depth were 23.7% and 20.8%. The smashed stalk length was less than 10 cm which was up to more than 90%. The germination rate was more than 90%. This improved the germinative rate of the seeds and achieved the joint practices model of smashing the straw and no-tillage sowing. The model also meets the requirements of conservation tillage technology in the area. 

Abstract:In order to obtain the best working parameters combination of spiral bar tooth thresher for maize seed production, parameters such as feed rates, threshing rotation speed of roller, spiral angle of bar tooth and exhaust core mouth clamp pressure were selected as independent variables, which would influence kernel broken rate of maize seed. Subsequently, the Box-Behnken experimental design with four factors and three levels was performed, and the mathematical model was established by using Design-Expert software. Then the effects of various parameters and their interactions were analyzed as well. The results showed that effects order of four parameters on kernel broken rate of maize seed were as follows: spiral angle of bar tooth, threshing rotation speed of roller, feed rates and exhaust core mouth clamp pressure. The optimal working parameters were feed rates of 2.8kg/s, threshing rotation speed of roller of 241r/min, spiral angle of bar tooth of 9°and exhaust core mouth clamp pressure of 40N, then the kernel broken rate of seed production of 0.366% was obtained, which was reduced by 0.084%~0.274% after the parameters optimization.

Abstract:A seeding accuracy test experiment based on soil substrate was investigated. The moving trolley carried the sowing seeders. Meanwhile, the machine vision system sequential images dynamically were collected. Using encoder and PLC etc., it realized to control camera to collect sequential images through detecting the motion distance of trolley, which realized hardware splicing of the sequential images. In addition of splicing algorithm of image processing, the identification of seeds and the total splicing of the sequential images were completed. Experimental results showed that the matching rate of seed spacing was above 85%, and the accuracy rate of seed spacing was more than 70%. The experiment was repeated many times. The absolute error of the seeding accuracy data was within 4%.

Abstract:Based on the problem of high seed damaging, a precision metering was proposed based on the pelleted corn seeds.The two times orthogonal rotational regressive tests were designed in the experiments. The rotary speed, diameter of the cell, cone angle of the metering seeding plate were defined as input parameters and seed damaging index was defined as output parameters. The regression mathematics models between output parameters and input parameters were established and then parameters were optimized through Design-Expert 7.1. The optimal combination was that the rotary speed of 13.2 r/min, diameter of the cell of 16 mm, cone angle of the metering seeding plate of 26.5°, at that time the seed damaging index of 0.65%. Confirmatory tests showed that the inaccuracy was little.

Abstract:Mechanism of inner mechanical cracks of corn seed kernel was researched by means of Cottrell piling up of dislocation theory. The formula of expanding speed and propagation route dimension of inner mechanical cracks were inferred based on theory of Griffith energy balance and fractal geometry. Crack growth rate was analyzed through fractal method. The results showed that inner mechanical cracks of corn seeds formed when part stress increased to a certain level. According to phoronomics formula of inner cracks propagation, the macro speed propagation was less than fractal propagation speed. Fractal dimension of 1.1395 was calculated by path formula of mechanical cracks propagation. The speed of cracks propagation along starch particles extending was faster than same size of starch particles.

Abstract:A droplet deposition and drift distribution model was established for super-high clearance boom sprayer with air-assisted system in accordance with the actual structure of sprayer. The CFD software ANSYS Fluent was used. The standard k-ε turbulence model, discrete phase model and couple algorithm were adopted. The simulation test was designed to study the relationship of drift rate with its influencing factors. The functional relation of droplet drift rate with its influencing factors at different rotation speed of axial-flow fan was established and the accuracy of the simulation result was validated. The results showed that, the model was well fitted, and the parameters of air-assisted system can affect the drift significantly. These conditions include angle of air-assisted flow, nozzle horizontal position, natural wind velocity, rotation speed of axial-flow fan, interaction between angle of air-assisted flow and natural wind velocity, interaction between angle of air-assisted flow and rotation speed of axial-flow fan, interaction between nozzle horizontal position and natural wind velocity, interaction between rotation speed of axial-flow fan and natural wind velocity. 

Abstract:In order to implement variable rate application control of intermittent spray based on pulse width modulation (PWM) technology, a blended pulse variable rate application controller was designed with its core part DSP56F805. The controller has two working modes. Operational parameters were set artificially in single mode, and received from upper computer through CAN bus in online mode. The controller can output 12 channels of PWM signal which can be adjusted individually. It also can monitor traveling speed of sprayer, rotational speed of diaphragm pump’s input shaft, spray pressure and application flow rates of each boom partition. In addition, the spray pressure can be regulated on line by predictive control algorithm with proportional relief valve. A variable rate application system was constructed by integration of a modified commercial boom sprayer and the controller, and its performance tests were carried out. Test results showed that the maximal effective frequency of the PWM signal was within 5 Hz, the ratio of flow regulation was more than 10, measuring error was within ±0.1 km/h for the traveling speed, within ±1.5 r/min for the rotational speed, within ±0.01 MPa for the spray pressure and within ±0.05 L/min for the flow rate, and regulating error of the spray pressure was within ±0.01 MPa in a 2 s regulating period.

Abstract:The influence of application parameters of unmanned aircraft on droplets deposition was researched. Temperature change rate was tested by thermal infrared imager to reflect the droplets deposit on rice canopy. The results showed that there was no difference with the droplets deposition and canopy temperature change rate as evaluation index. Thermal infrared imager could reflect the droplets deposit law exactly. The optimum application parameters of WPH642 unmanned aircraft were that flight altitude of 2m and flight velocity of 1.5 m/s. 

Abstract:The trailing edge of wind turbine airfoil S822 was modified by adding a Gurney flap and smoothing the lower cambered surface. The aerodynamic characteristics of S822 airfoil and its improved Gurney flap airfoils were studied with k-ω SST turbulence model. The effects of the flap height and starting modification position on the lift and drag coefficients, lift drag ratio, airfoil surface pressure distribution and flow field characteristics were analyzed. The results showed that if the starting modification position was the same, the lift coefficient in certain range of attack angle and the drag coefficient increased with the increasing of the flap height. The lift-drag ratio was the maximum when the flap height was 2% chord length. If the flap height was the same, the lift coefficient and lift-drag ratio increased, and the drag coefficient changed little when the starting modification position was gradually close to the trailing edge. The research can provide references for designing airfoils of wind turbine blade.

Abstract:Combined with Savonius rotor is an important way to improve starting performance of straight-bladed vertical axis wind turbine (SB-VAWT). The starting performance of the combined type VAWT was largely affected by the combining angle of the two type turbines. Firstly, an SB-VAWT with NACA0018 and FX63-145 airfoils and a Savonius rotor were made and their starting performances were respectively tested. Then, optimal starting performance area of Savonius rotor was respectively combined with optimal starting performance area and the worse starting performance of SB-VAWT, starting performances of combined type VAWT with four different combining ways were tested by using a wind tunnel. For SB-VAWT with symmetrical airfoils, better starting performance of combined type VAWT can be obtained when its optimal starting performance area was combined with Savonius rotor. For SB-VAWT with asymmetric airfoils, both of the two ways have advantages and disadvantages. 

Abstract:Change regularity of physicochemical properties of corn straw, peanut shell and sawdust which are supplied from different seasons was studied based on a case study of biomass solid fuel plant in Daxing district of Beijing. The results showed that total moisture of sawdust was higher, more than 40%. Total moisture of corn straw and peanut shell was about 10%. The bulk density, flow characteristics, calorific value, ash, volatile matter of three types of raw materials were varies. Sawdust had relatively high bulk density and volatile matter but lower ash. Peanut shell and sawdust dry basis calorific value was higher than corn straw high. However, as received basis calorific value has lower. Physicochemical properties of the same materials of different season were different; especially total moisture varied with the local climatic conditions. After June, dry basis calorific value of corn straw, peanut shell and sawdust were reduced about 7%, 3.5% and 5%. Therefore, difference of physicochemical properties of several of raw materials such as bulk density, flow characteristics should be fully considered during related equipments design process of storage, transport, and compression forming of raw materials. Furthermore for the combustible characteristics of raw materials, not only difference of physicochemical properties should be considered, but also different seasons.

Abstract:Taking the physical model of cylindrical biogas digester as the research project to design automatic flushing basin of biogas digester, the flow of the digester was rotated by designing feed pipe to be tangential. Fluent was used to analyze the process. It was found that the grit deposition area that was on lower left bottom. Based on the theory of hydraulic similarity, the design digester and the conventional digester were established. The angle between grit discharge pipe and feed pipe was designed for 150° according to the sedimentation law. Water was used as experiment fluid, whose sand contents were 10%. The results showed that sand would be collected at the 3rd discharging at design digester, the grit removal rate was up to 86.13% at the 5th, the average grit removal rate for 19 times was 3.81 times of the conventional, and the average of the 5th to 22nd was 82.17%. The grit removal result of conventional was exceeded by the design.

Abstract:For the problems of production record information of agricultural products traceability system being unitary and less information, the video record of agricultural products traceability system was designed and developed, which achieved the purpose of the production process quality traced. The ARM9-based embedded technology with H.264 compression technology was combined, which collected and compressed the video record of agricultural products. And 3G wireless transmission technology was used for transmission of the video record. The video record production server was for storing the video record. Finally, the users can trace the video record by the software of the video record of agricultural products traceability system which was developed by the platform of .NET. The system collected the video record of the different stages of agricultural products, thus provided a more intuitive, abundant and persuasive information for agricultural products. The results of the system showed that the system had the versatility, high reliability, good stability, portable features, easy application for greenhouses and farms, thus other agricultural products to meet the different needs of users.

Abstract:According to the characteristics of farm products quality safety incidents, ten samples were processed by the reduction and analysis of attributes using the rough set method, and five indexes were determined. The indexes was toxicity of pollution source, scope of pollution influence, number of death, number of injuries and population density, whose weights were 0.2, 0.2, 0.1, 0.3 and 0.2, respectively, according to the importance analysis of the indexes. Based on these, a grade evaluation model of farm products quality safety accidents was established. An emergency management system of farm products quality safety was designed and implemented by programming the grade evaluation model using WebGIS. Through simulating a particular farm products quality safety accident, the result showed that the system could improve the handling ability of the accident, and realized the visualization of the disposal process. The system can provide consultation for farm products quality safety management. 

Abstract:The intelligent olfactory spectrograms of Xihu Longjing tea were collected by electronic nose. The spectrograms scores matrix that obtained by principal component analysis was applied. The influence of the information from grading, tree varieties and producing areas on quality of tea was analyzed. The soft independent modeling of class analogy was used to establish three kinds of models for grading, tree varieties and producing areas, respectively. Results showed that the intelligent olfactory spectrograms from different grading tea had the most difference than the other two elements. The grading discrimination model had well performance with about 100% correct rate to predict top grade teas. Meanwhile, the influences of tree varieties and location on the tea quality were seemed to be similar. Under the same grade and same producing area, the tree varieties discrimination model of tea was built. Also, the producing area discrimination model of tea was built. The correct rates of the two models were all over 92%. On the basis of above study, the quick detection strategy of Xihu Longjing tea by intelligent olfactory technology was presented, that is, grading demarcation, tree varieties identification and producing area distinguishing under the same grading were carried out in turn.

Abstract:In order to achieve the rapid prediction of aureomycin contents in duck meat, quantitative analysis models of aureomycin contents in duck meat were established by using synchronous fluorescence spectroscopy and LSSVR method. Firstly, synchronous fluorescence spectroscopies between 250 nm and 450 nm were analyzed by using 3-D synchronous fluorescence spectroscopy, and 70 nm was selected as the optimum wavelength difference. Secondly, the sym8 wavelet with two levels decomposition was used to complete the pretreatment of the original synchronous fluorescence spectroscopy, and 16 characteristic wavelengths were selected as the inputs of detection model combining with genetic algorithm and the root mean square error of cross validation. Lastly, the performances of three models of LSSVR, BP and SVM_SteveGunn were compared. LSSVR model was optimal among them, and the determination coefficient R2 and the root mean squared error of prediction samples were 0.9491 and 2.5660，respectively. The experimental results showed that it was feasible to predict the aureomycin contents in duck meat combining with synchronous fluorescence spectroscopy and LSSVR. 

Abstract:In order to investigate the feasibility of sample-sample 2-D correlation near infrared diffuse reflectance spectroscopy method for different protein feeds rapid identification，52 fish meal samples and 60 soybean meal samples were collected，including 74 calibration samples and 38 independent validation samples. Samples were measured by spectrometer. Calibration model was established by sample-sample 2-D correlation spectroscopy method with the pretreatment of 3-point first derivative. This method performed 100% of correctly classified samples. Compared with partial least squares discriminant analysis method, both of them can correctly identify the fish meal and soybean meal. But the sample-sample 2-D correlation spectroscopy method is fast for calculation.

Abstract:The indicators about ageing mechanism including pH value, content of glycogen, myofibril fragmentation index (MFI), the activities of calpains and cathepsin L and meat quality including pressing loss, cooking loss, shear force and chromaticity during ageing of eight days were determinated from ten Qinghai yaks. The correlation between shear force and MFI, activities of calpains and cathepsins L were also analyzed. The results showed that the all above mentioned indicators changed during the ageing period, and the direct reflect was improving the yak meat tenderness. MFI had a very significantly（P＜0.01）correlated with the activities of calpains, and had a significantly correlated with the activity of cathepsin L（P＜0.05）, while there was a significant negative correlated with the activity of cathepsin L（P＜0.05）.

Abstract:In order to study the impact of microwave radiation on wheat germ (WG) quality, a continuous microwave radiation system was constructed. Scanning electron microscopy and micro viscometer were used to detect the influence of microwave radiation on microstructure and starch pasting characteristics of WG. The results showed that the continuous microwave radiation system had a good stabilization effect on WG. The majority starch granules in microwave-treated WG were still intact observed by SEM, accompanied by a clear outline. However, with the microwave radiation intensity increased, the original spatial structure changed among starch granule, oil and protein. The gelatinization temperature of microwave treated WG rose to a range of 59.3～65.4℃. Depending on their extent of pre-gelatinization, different WG samples gave significantly different peak viscosity (349～466 BU) and break down values (69～87 BU). Compared with that of raw WG samples, the fatty acids composition and tocopherol content of WG treated by microwave did not change significantly. The above results showed that microwave radiation did have some effect on WG quality, but less than traditional heating methods. Microwave stabilization should have a good prospect for industrial application.

Abstract:The combined effects of CO2 and cold seawater on the quality of Pacific white shrimp (Penaeus vanmamei) during the storage were investigated. The results showed that the total bacterial count (TBC), Escherichia coli count, H2S producing bacteria count and psychrophilic bacteria count of shrimp preserved in CO2-cold seawater (4℃) were lower than that of control group (samples were not in CO2-cold seawater but cold stroge). As a result, total volatile basic nitrogen (TVB-N), pH value and K value increased more slowly than that of control during storage. Shrimp in CO2-cold seawater was second-grade freshness (TVB-N value of 19.5mg/(100g), K value of 20.3%) after storage eight days comparing to serious spoilage of control. The shear force of shrimp flesh decreased slowly during storage, but there was no obvious difference. Activity of polyphenol-oxidase (PPO) was significantly inhibited by CO2-cold seawater. Meanwhile, melanosis of shrimp and deterioration of sense quality was delayed.

Abstract:In order to improve orchard automation, an identification and location system of apple picking robot was developed. In order to overcome dependence of existing system on the working distance, human picking process using a web camera and a Kinect sensor was imitated. Compared with manual measurements after calibration, the standard deviation of binocular vision in three directions were 3.4 cm, 1.2 cm and 1.2 cm, respectively. An apple detection and location method was developed based on color, shape and position. The results showed that when the working distance was about 240 cm, the mature apples can still be accurately identified and located, the standard deviation of binocular vision in depth direction was 4.9 cm. When the working distance was about 150 cm, the standard deviation of binocular vision in depth direction was 2.4 cm. When the working distance was less than 100 cm, the standard deviation in depth direction was less than 1.0 cm with web camera. 

Abstract:It is chosen as research object that joint robot arm avoids erect stem or strut to pick tomatoes, and a kind of obstacle-avoidance path planning method based on configuration space of joint robot arm was presented. Space mapping principle was used to transform obstacle-avoidance problem of joint robot arm in 3-D workspace into avoiding obstacle circle problem of planar R-R robot arm. Critical collision joint angle was used to build up mapping computation models of configuration obstacle space of planar R-R robot arm, and obstacle-avoidance position computation of joint robot arm in 3-D workspace was transformed into joint angles computation of linkages in configuration space. After terminal joint angles of obstacle-avoidance path planning were optimized according to optimal energy function, the obstacle-avoidance joint angle path of planar R-R robot arm based on A* arithmetic was computed. A series of intersectant erect planes described space link position were obtained and the planning of other joint was carried out in the intersectant erect planes. The test of avoiding erect obstacle to pick tomatoes showed that joint robot arm carried with the gripper can move round linear obstacle and guide the gripper to reach object position. The test proved that mapping computation models of configuration obstacle space of planar R-R robot arm were correct. It validated that the obstacle-avoidance path planning method was feasible and may be applied into automatic harvesting of tomato. 

Abstract:In the research of segmentation of the target image for tomato harvesting robot, the accuracy was affected by illumination and calculation complication. Firstly, the characteristics of RGB, HIS and YUV color spaces were compared. It was theoretically analyzed that the YUV color space applying to tomato harvesting robot vision system was feasible. Then, the threshold value of the ripe tomato in their color spaces was given according to the results of experiments and experience. The double-threshold algorithm based on YUV color space was put forward to apply to the tomato harvesting robot vision system. And the experiments under different illumination were designed to segment ripe tomato respectively in RGB, HIS and YUV color space in order to test the effect of those algorithms. The experiments also showed that the algorithm based on YUV color space had the better robust and the better real-time than the others. 

Abstract:The position accuracy is mainly decided by the accuracy of landmark directional angle for the localization system of agricultural machinery based on omnidirectional vision sensor. The algorithms about low pass filter eliminating noise and artificial landmark features detection was studied. After eliminating noise, the red pixels intensity was calculated and the red landmark pixels beyond the threshold were extracted. Based on the Euclid geometrical distance of neighbor pixels, the small area of pixels was divided and the center of gravity was calculated for the extracted small area representing the candidate of one landmark. The algorithm provided the blue patch as compensation to further distinguish the landmark from other objects in a complex environment. The landmark detection test proved that the low pass filter eliminating noise was effective. Pointing, straightaway driving and tilt tests were conducted on the level ground in a 30 m×30 m area outside. Results showed that the average values of MAE and RMSE of landmark direction angles were 1.12° and 2.10°, and the influence of vehicle vibration and tilt angle less than 5° were not obvious. The positioning accuracy was about 10 cm. The proposed algorithm is feasible, the error of landmark direction angle is less and the program is fast running speed and robustness. 

Abstract:The non-uniform intensity distribution on the fruit’s images is the main reason resulting in the difficulty and low accuracy of surface defects detection by using a machine vision system. A detection system based on Vis NIR double CCDs was built for detecting surface defects on ‘Akesu’ apples. A spherical intensity transformation method (SITM) was proposed to transform the R channel image of an apple, which enhanced the intensity uniformity of the normal regions and kept the low intensity of the defected regions in an apple. The intensity contrast between the defect regions and those of normal tissue was also improved, which increased the defect detection accuracy. A defect detection algorithm was developed based on the SITM and 100 apples consisting of 45 defected apples and 55 intact apples were used to evaluate the performance of the algorithm. Results showed that 93.3% of defected apples were correctly classified and 100% of the intact apples were correctly recognized. The overall detection accuracy was 97%. It is feasible to extract the surface defects on apples using the proposed SITM combining with a single threshold segmentation method.

Abstract:In order to solve the problem that the infrared light sensor and the visible light sensor can’t get clear images simultaneously, a nonsubsampled Contourlet coefficient compressive sensing based on infrared and visible image fusion method was proposed. Firstly, the nonsubsampled Contourlet transformation method was used to do multiscale multi directional image decomposition for the infrared and visible image. Each nonsubsampled Contourlet coefficient of them was got. Then, the low-frequency coefficients of the infrared and visible image were fused by the weighted average fusion method. The band pass sub band coefficients by the pseudo random Fourier matrix observations weights fusion method were used. After that, fused band pass sub band coefficients were reconstructed. Finally, image by the inverse nonsubsampled Contourlet transformation were reconstructed. The experiment results showed that this fusion algorithm can get image with clear object and background, and it has the low computational complexity and good fusion effect. 

Abstract:This research focused on the detection of trashes at the depth of 1～6mm in the cotton using hyper-spectral imaging and pixels classification. In the wavelength range of 460～900nm, the detection algorithms were developed based on pixel’s spectra of hyper-spectral image, pixel classification by quadratic discriminate analysis, and binary images post processing by combining area filter with morphologic process. The results indicated that hyper-spectral imaging was able to detect some trashes at certain depths in the cotton, such as natural trashes, color polypropylene fibers, color yarn and fragments of cloth. And it also can detect some black hair and gray polypropylene fibers. In particular, the detection effect for natural trashes was the best. The detection rates for natural trashes were over 80%.

Abstract:In order to provide techniques for digital design of the 3-D shape and visual simulating of tomato, on the foundation of observation, measurement and analysis of long term on tomato, the classification modeling of configuration of leaves and lateral branches was put forward based on measured data. Leaves and lateral branches were classified, and template libraries were constituted, which contains 2～4 temples respectively. Several principal control parameters with explicit biological background for these geometric models of organs were extracted based on the morphological features of tomato. Interactive designing the 3-D shape and organs of tomato were implemented by using template techniques. The models designed by this method, which presented polymorphism and have high realistic, could be integrated with agricultural knowledge easily. An interactive design software based on geometric model of tomato organs was exploited, by which users can design tomato plant model interactively. The digital model appears polymorphism, and ratios of model and real plant that the vertical projection leaf area and total leaf area were compared, they were 0.4788 and 0.4832, respectively, the error between them was 0.91%, so it has a high sense of reality.

Abstract:In view of the incubation process which is highly nonlinear, large delay and time-varying and strong coupling, a combination forecasting method based on gray prediction and associative memory neural networks was proposed. Firstly, the gray prediction model and associative memory neural networks were respectively used on prediction for incubator. Then the two sub-models with weighted integration by using the variance covariance combination forecasting method was combined. The value of the temperature and humidity of incubator could be more accurate and effective. Finally, the results showed the mean square deviation of combination forecasting model was 0.9%.

Abstract:In order to correctly identify common stress types of plants, because the wavelet packet has superior ability in feature extraction, the way to optimize the wavelet packet decomposition by use of the fuzzy criterion was proposed. Then BP neural network classifier should be employed to distinguish different stress factors according to physical characteristics of electrical signals performed by plants under diverse stress factors. Because plant electrical signals are very weak, de-noising method based on wavelet packet was used. Afterwards, after wavelet packet was optimized by fuzzy criterion to acquire the feature sets composed of optimal wavelet packet base energy values which can be differentiated easily, electrical signals from plants exposed to a variety of stress types were decomposed by using wavelet packet. In the end, the feature sets were input to a certain BP neural network which is more suited for processing fuzzy and nonlinear signals to finally identify stress types. The results of the study showed that average rate reached to 95.95%. This proposal was proved to be relatively precise and practical after the analysis of four plants including aloe, Jasper, Sansevieria and Schlumbergera, all of which were exposed to seven kinds of detrimental factors. 

Abstract:To explore the temperature distribution in the simple plastic greenhouse of south China, a model was established including component of inner and outer space, inside plant and soil layer, etc. Based on analysis of solar radiation and heat exchange between different components, 3-D steady simulation of temperature distribution was carried out in greenhouse. The Monte Carlo model was adopted in thermal radiation and transfer process, shear stress transport (SST) model was used in air turbulence analysis, and the crop was simplified as continuum. The result showed that the value of simulation was a bit higher than that of the measurement. The absolute error was below 2.2℃ and relative error was 6.7%. The airflow had an obvious effect on temperature distribution and fluctuation, and the temperature of inlet side was lower than that of outlet side. It seems feasible to consider the crop as continuum in simulation model in this case, while the simulation value showed a bit higher. 

Abstract:Aimed at meeting the requirements of facility agriculture precision control，a kind of high efficient remote precise measurement and control system of facility agricultural based on ZigBee and 3G is proposed. Through the ZigBee wireless sensor network, the system realize the collection of local environmental information and upload the data to the embedded server. The system connect internet through 3G network, which could construct a big range and low cost wireless network. B/S (Browser/Server) structure was used in the system, which could realize remote real-time monitoring environmental data information and video information. The embedded expert system model make this system automatic and intelligent. The experimental results showed that the performance of the system was quite stable and the system satisfied the design requirements in real-time data acquisition wirelessly, environmental automatic control and environmental visualization control remotely. And this system has a very well real-time nature and expansibility. The system has a good application prospect in automatic and intelligent facility agriculture.

Abstract:Based on force screw equilibrium equation of a kind of 6_PUS parallel mechanism and decomposed force of its branches, force Jaccobian was derived and then kinematic Jaccobian was got. By kinematic Jaccobian, singurality conditions of 6_PUS parallel mechanism were achieved and the geometry characteristics in two kinds singularities of this parallel mechanism were drawn. In order to study conveniently on singularities of the mechanism in its’ full work space, a concept that called singularity field was put forward to express the mechanism actually running. As the base to research singularity and to avoid singularity, the expression equations of singularity field were built. The distribution of two kinds of singularities in full work space of this 6_PUS mechanism was obtained and methods for avoid singularities or forbid mechanism running at singularities point were brought out for reference to design of this kind mechanism. 

Abstract:A rotary electromagnet with high pressure resistance based on axial stator division structure was proposed. Combined with the approaches of magnetic circuit analysis, numerical simulation and experimental study, the static and dynamic characteristics of electromagnet including torque-angle relationship, frequency response and step response were studied. The simulated frequency width was 115 Hz/-3 dB,80 Hz/-90° approximately and the simulated rise time for step response was about 15 ms. In order to validate the accuracy of theoretical results, a special test rig was built and experimental study was performed. The electromagnet has sinusoidal-like torque-angle characteristics whose maximum static torque reached about 0.19 N·m. And its experimental frequency width was 113 Hz/-3 dB, 65 Hz/-90° approximately and experimental rise time was about 18ms. The experimental results were in a close agreement with the simulated results. The electromagnet was appropriate to be used as the electro-mechanical converter of 2-D direct-drive digital proportional valve.

Abstract:A kind of piezoelectric resonant diaphragm air pump was proposed, which is based on the system resonant principle. Firstly, the working principle of the piezoelectric resonant diaphragm air pump was analyzed and a dynamic model of the pump resonance was established. The main factors of the output flow rate can be obtained. Then a prototype was designed. The testing facility was developed to measure the volume of the resonance pump. Finally, the variation of output flow rate on different vibrating spring rate, adjusting spring rate and diaphragm rate were obtained by experiment test. Experimental results indicated that the maximum flow rate was 1650 mL/min when he sinusoidal AC driving voltage was 150 V, the vibrating spring thickness was 0.6 mm, the adjusting spring thickness was 1.4 mm, and the radius ratio of the rigidity transfer vibration piston and the diaphragm was 0.5. And the amplification factor of the piezoelectric vibrator was 5.3 by using the proposed photovoltaic displacement sensor. 

Abstract:The system deviation according to disruption management were measured from the following three aspects: the customer dissatisfaction, operational cost and processing sequence of jobs. Then, the multi-objective model of disruption management based on the lexicographic multiple goal programming was constructed and an improved ant colony optimization was demonstrated. Finally, the effectiveness of model was validated by a case. The computational result proved that, due to the tradeoff between all parties involved in the single machine scheduling, the proposed model was more practical than existed global rescheduling model.

Abstract:Four different test samples (no deflector, deflector with one hole, deflector with five holes, and deflector with twelve holes in the manifold) of micro-channel evaporator with parallel flow were processed. Flow distribution characteristics of deflectors were experimentally studied with water as the working fluid. The results showed that when the entrance Reynolds number was less than 3000, the influence of which on the flow distribution characteristics of both the samples without deflector and with the deflector with one hole was apparent, and the flow distribution uniformity and stability of the two test samples were poor, but the sample without deflector was better than the deflector with one hole. After the entrance Reynolds number was more than 3000, the uniformity and stability of the deflector with one hole was becoming better, but the uniformity of the sample without deflector was the worst in four of the test samples. The deflector with five holes had the good and stable flow distribution uniformity when the Reynolds number was less than 4000. As the Reynolds number was more than 4000, the flow distribution uniformity was worse. In comparison, the flow distribution uniformity and stability of the deflector with twelve holes were always the best in all the test samples, and as the entrance Reynolds number increased, the uniformity of flow distribution was improved slightly. 

Abstract:Static stiffness of a vertical machining center was researched based on fine experiment and finite element method. Static stiffness of three directions and deformation of the main parts were measured. Deformation of the spindle box was measured and detailed analysis was taken. Deformation of the joint between spindle box and column was measured. The results showed that weak leak of the joint is y direction. Finite element model of the machining center was established in Workbench and accuracy of the model was verified compared with experiments.

Abstract:Based on the geometrical theory of the form milling the spiral taper gear, the computational formula of the cutting thickness and cutting width in every time was deduced. The milling force model for form milling the spiral taper gear was presented. The milling force factors were calibrated via single factor experimentations and the form milling force simulation programs were prepared. Experimental installations were designed to validate the availability of the milling force model. Comparison between the computational results and experimental observations confirmed the validity deviation of the proposed model was within ±15%.

Abstract:The quasi-static and dynamic mechanical properties experiment of Al6061-T6 in high temperature (20~500℃) and high strain rate (up to 104/s) was carried out on the quasi-static press and split Hopkinson press bar (SHPB) equipment. Then the effect curves of strain hardening, strain rate strengthening and thermal softening were obtained. According to these curves, the classic JC (Johnson-Cook) equation was modified. Furthermore, the modified JC equation was validated in the high speed cutting physical simulation model. The results showed that the Al6061-T6 flow stress increased with the increasing of strain and strain rate, and obviously decreased with the increasing of deformation temperature. The description accuracy of the modified JC equation was higher than the JC equation. The obtained Al6061-T6 constitutive equation can provide important material parameters for physical simulation models of its high speed machining process.

Abstract:A 2-D sliding model of micro-scale was established between two rough surfaces exhibiting fractal behavior, and the stress and strain was discussed by using the finite element analysis. A pair of asperities was analyzed take into account elastic-plastic material properties with material failure. The transient stress/strain distribution of the rough solid was presented. The numerical results showed that the equivalent plastic strain versus different depth which at different locations showed different laws. Failure began beneath the surface at the region of highest plastic strain. A shear stress zone exited at a certain depth from the contact surface in the rear of the contact asperity. This shear stress zone on the one hand prevented the crack from extending along the depth direction, on the other hand, prompted the crack along an extension of the parallel to the direction of the friction surface crack growth and leads to final fracture.