Abstract:The purpose of this article is to explore the objectives, tasks and policies of smart agricultural development in the future of China. Based on the perspective of system engineering, the concept and connotation of smart agriculture were expounded. The strategic layouts and action plans of smart agriculture abroad were introduced. The development status and characteristics of domestic smart agriculture and the gap between China and the world were analyzed systematically, and the development objectives, key tasks and policy suggestions for smart agriculture in the future of China were put forward. Agricultural developed countries, like United States, Germany, Britain, Japan, etc., occupy the international forefront in the fields of intelligent agricultural science and technology, such as agricultural sensors, agricultural big data intelligence and agricultural intelligent equipment. In China, the R & D and application of smart agricultural technologies, including common environmental agricultural sensor, agricultural remote sensing technology, agricultural UAV, agricultural machinery Beidou navigation, agricultural big data and intelligent algorithm, have made great progress under the trend of policy guidance and large-scale operation, and some imported technical products have been replaced by domestic products. Developing smart agriculture is an important part of China’s high-quality agricultural development strategy during the 14^th Five Year Plan period and even to 2035. In view of the problems, such as the fragmentation of farmland plot, the low level of agricultural mechanization, the weak rural infrastructure, the insufficient effective supply of smart agricultural technology, and the imperfect policy system and market mechanism, the development of future smart agriculture urgently needs to focus on technology research, application demonstration, policy experiment and social experiment together.

Abstract:Smart agriculture is an advanced form of modern agriculture. Unmanned farm is an important way to realize smart agriculture, and intelligent agricultural machinery is the material support for unmanned farm. Took plant production of intelligent agricultural machinery in smart agriculture as an example, this paper introduced the research progress of status and key technology of four functions of intelligent agricultural machinery, including intelligent information sensing, automatic navigation, precision operation and smart management. South China Agricultural University integrated the intelligent agricultural machinery of rice production and built the unmanned rice farm. The five characteristics of unmanned rice farm are summarized as follows: 1) All production processes, including cultivation, planting, management and harvesting are unmanned; 2) Transfer between hangar and field, and operation are full-automation; 3) Avoiding obstacle and parking automatically at abnormal condition ensure the safety; 4) Real-time monitoring of all production process; 5) Unmanned intelligent decision-making and precision operation. In the production of medium rice in 2020 and early rice in 2021, the yield of rice in unmanned farm was higher than the average yield in traditional farm, which indicated that unmanned farm had great development potential. The construction of unmanned rice farm provides an important way to solve the problems of “who will farm” and “how to farm” in the future of China.

Abstract:The modern livestock and poultry breeding industry in China has been rapidly developing towards scalization, facility, standardization and informatization. The research, development and application of intelligent farming equipment and information technology have become the key to promote healthy and sustainable development of livestock and poultry breeding industry. It is of great significance for improving the output efficiency, reducing the dependence on labor in the production process, and achieving green and high-quality transformational development of livestock and poultry breeding industry in China. To meet the needs of quality and safety of products, healthy management, and quality-efficiency improvement of large-scale livestock and poultry production, this paper mainly summarized the latest research and application progress of intelligent equipments and information technologies, including modularized assembled animal buildings and building-thermal environment coupling regulation technology, precise monitoring and intelligent controlling technology of farming environmental parameters, intelligent feeding, drinking and dosing equipment, automatic manure removal technology and equipment, real-time information collection and intelligent management technology etc. The weak links and bottlenecks for the development of intelligent equipment and information technology of livestock and poultry breeding industry were pointed out. The development direction of mechanization and intelligent equipment of livestock farm in China was prospected. This review provides a reference for the green and high-quality transformation and upgrading, healthy and sustainable development of livestock and poultry breeding industry in China.

Abstract:In recent years, the development and innovation of no-tillage seeding machines have promoted the rapid progress of conservation tillage technology in China. With the development of precision agriculture and control technology, the research and application of row stubble avoidance, seeding rate and seeding depth monitoring and control technology have improved the intelligence of no-tillage seeding machines. Taking no-tillage seeding as an example, this paper introduces the research status of mechanical tactile technology, machine vision technology and modern control methods in no-tillage seeding row-follow stubble avoidance technology, expounds the application status of infrared detection technology, capacitance detection technology and image detection technology in no-tillage seeding rate monitoring, and introduces the research status of active and passive adjustment methods in no-tillage seeding depth monitoring. The future development direction of no-tillage seeding intelligence is prospected from the aspects of navigation fusion, algorithm and sensor research.

Abstract:Objective In order to explore the effect of reduced pesticide application on the control effect of rice planthopper by multi-rotor plant protection UAV and promote the development of reduced pesticide application technique for rice.Method Field experiment was carried out using an M45 multi-rotor plant protection UAV for rice pesticides application. We used two spray volumes of 15.0 and 22.5 L/hm², and three pesticide dosages of 100%, 90%, and 80% of the conventional artificial control dosage. The effect of different spray volume and reduced dosage on the droplet deposition and the control of rice planthopper were analyzed.Result The droplet deposition in the upper part of the rice canopy was significantly higher than that in the lower part of the canopy. The differences of two spray volumes and three dosages on the droplet deposition were not significant. At the same time, the number of rice planthopper decreased significantly after one week of treatment. Under the condition of the same spray volume, the effect of reduced dosage on the control effect of rice planthopper was not significant. Rice spray dosage of 80% of manual application met the requirement of rice planthopper control.Conclusion The spray dosage of 80% can be considered as feasible dosage in the UAV application for rice. The results provide useful reference for promoting the reductions of pesticide application for rice and the operating cost of rice plant protection.

Abstract:Objective To obtain rapeseed sowing quality information and realize information display, remote transmission and cloud storage, a rape sowing quality monitoring system was proposed.Method This system consisted of rapeseed sensor detection device, seeding monitoring terminal and seeding quality information cloud storage platform. Various forms of small particle size seed sensor detection devices were used to achieve real-time acquisition of sowing quality information, and a radio frequency communication module was used to achieve data interaction with the sowing monitoring terminal. The monitoring terminal completed the information display and realized the accurate positioning of the sowing quality information position through the Beidou positioning unit. This system realized the remote transmission and cloud storage of rape sowing quality information through wireless transmission module. A bench test of the rape sowing quality information collection system was built and field performance tests were conducted to verify the stability and reliability of this system.Result The designed seed quality information acquisition system could obtain seeder longitude and latitude information through the embedded Beidou positioning unit, and transmitted the seed quality information and positioning information to the cloud storage platform by 4G wireless transmission module. The bench test results showed that the detection accuracy rate was not lower than 97.1% when the seed dropping frequency of seed platter was 16.5?26.2 Hz. The collected seed quality information of rapeseed could be transmitted to the seed monitoring terminal and displayed. The seed quality information was accurately uploaded to the database of cloud storage platform, the transmission time did not exceed 2 s, and the information was consistent with the terminal display data. The field test results showed that the detection accuracy was no less than 96.6% at the seed dropping frequency of 17.4?25.5 Hz, and the system operated normally.Conclusion This system provides the support for the intelligent improvement of seeding process, the generation of seeding state diagram, and yield prediction.

Abstract:Objective The small-grain seed has the characteristics of small size, light weight and irregular shape. The problems of blockage of seed suction hole, seed damage and poor seeding uniformity often occur in the operation of traditional seed metering device. Therefore, on the basis of seed pelleting technology, an air-suction precision hole sowing seed metering device for small seeds was designed.Method The seeding process was simulated by Rocky discrete element simulation software by measuring relevant parameters such as seed size and friction angle. In order to obtain the best performance factor combination of the seed metering device, the quadratic regression rotation orthogonal experiment was carried out, and a multi-objective optimization method was used to optimize the factors affecting the performance of seed metering device.Result Through the test of regression coefficients, the primary and secondary order of the factors affecting single grain rate and leak seeding rate of the seed metering device was air pressure and rotation speed of seed metering device. When the rotation speed was constant, with the increase of the negative pressure, the single grain rate increased, and the leak seeding rate decreased; When the negative pressure was constant, with the increase of the rotation speed, the single grain rate decreased, and the leak seeding rate increased. When the negative pressure was greater than ?2 800 Pa, the rotation speed of 5?30 r/min had less obvious influence on single grain rate and leak seeding rate of the seed metering device, and the single grain rate was all above 90%, the leak seeding rate was all below 10%.Conclusion Through optimization, the optimal working parameter combination is the rotation speed of 15 r/min, the negative pressure of ?2 300 Pa, and the positive pressure of 500 Pa. The performance indicators of the seed metering device under these conditions are as following: The average single grain rate qualified index is 96%, the average leak seeding index is 3.37%, and the average replay seeding index is 0.267%, which conforms to the national standard requirements.

Abstract:Objective This study was aimed to design a air-assisted sprayer for the wind requirement of fruit tree with Y-typed trellis, explore the spraying regularity of applying the machine to such type of tree, and provide references for designing plant protection equipment for the orchard with new planting technology.Method According to wind demanding characteristic of the Y-typed canopy of pear trees, a special-shaped duct was designed. The duct could be adjusted according to different conditions, and the range of spray could cover tree canopy completely. The whole machine was configured, and the fan speed was adjusted using a stepless speed regulation pulley. The operating speed, outlet wind speed and height difference between the outlet and the middle of canopy were taken as test parameters, and the droplet coverage rate on target, the droplet deposition of target and the droplet deposition on ground were taken as evaluation indexes. The Design-Expert software was used to establish response surface, analyze the influence of parameters on the indexes, and optimize the operating parameters of the machine.Result The optimization results showed that when the operating speed was 0.8 m/s, the outlet wind speed was 22 m/s and the height difference between the middle part of the air outlet and the middle part of the pear canopy was 5.1 cm, the droplet coverage rate on target was 39.79%, the droplet deposition was 9.89 μL/cm², the droplet deposition on ground was 5.41 μL/cm², and the ratio of effectively attached liquid was 60.1%.Conclusion This machine can satisfy the requirements of orchard operation with good spraying effect. It provides a reference for the design of sprayer for rack type orchard and the optimization of machine parameters.

Abstract:Objective To analyze the noise in the air outlet of wind driven sprayer, explore the appropriate noise reduction methods and improve the noise reduction effect.Method This paper analyzed the noise frequency spectrum in the air outlet of the wind driven sprayer, adopted the narrow-band active noise reduction method to reduce the noise of fan outlet, analyzed three common noise reduction algorithms, comparatively considered the convergence speed and noise reduction performance of three algorithms, and selected the NLMS algorithm as the core algorithm. In order to improve the frequency disturbance caused by non acoustic sensors in the narrow-band active noise reduction system, genetic algorithm was introduced to optimize the initial frequency calculated by the acquisition parameters of the rotator. The fan noise was taken as the input signal, and five frequency channels (197, 394, 591, 788 and 985 Hz) were used for narrow-band active noise reduction simulation.Result The noise of the wind driven sprayer was mainly rotating noise caused by fan blade rotation. The simulation results showed that the system performance was improved after 33 iterations of the genetic algorithm. When the NLMS algorithm was iterated 10 000 times, the system converged, and the amplitudes of the five frequency channels were reduced by 0.192, 0.041, 0.024, 0.018 and 0.210 mm respectively, and the overall noise reduction effect was about 14 dB.Conclusion The NLMS algorithm has better reduction effect on the noise of wind driven sprayer. Genetic algorithm can effectively improve the frequency disturbance caused by non acoustic sensors. This study provides a reference for active noise reduction methods of wind driven sprayers.

Abstract:Objective In order to improve the mechanization level of organic fertilizer application in the greenhouse and solve the problem of low fertilizer discharge stability of the existing organic fertilizer discharging device, an organic fertilizer discharging device with scraper conveyor for greenhouse was designed.Method Taking the strawberry planting greenhouse in southern Jiangsu area as an example, the main requirements for the design of the fertilizer discharging device were determined according to the basic size parameters of the greenhouse and the agronomic requirements of strawberry planting. The key structure and parameters of the designed fertilizer discharging device were analyzed and determined by combining the bulk mechanics theory, and the main factors affecting the stability of the fertilizer discharging volume were determined to be the rotational speed of the fertilizer discharging shaft and the opening degree of the fertilizer discharging device. An indoor organic fertilizer discharging test platform was built, and single-factor test and two-factor five-level response surface test of rotational speed and fertilizer discharging volume were conducted.Result The results of the correlation test between rotational speed and fertilizer discharging volume showed that within the range of rotational speed and opening degree set in the test, the rotational speed and fertilizer discharging volume had a good linear relationship under the conditions with different opening degree. The overall coefficient of determination was above 0.9857, and the fertilizer discharging volume could be adjusted by adjusting the opening degree and rotational speed in real time. The results of the response surface test showed that the stability of fertilizer discharging volume within the set range was good, and the rotational speed of the fertilizer discharging shaft had a greater influence on the coefficient of variation of the fertilizer stability compared with the opening of the fertilizer discharging device. The coefficient of variation of fertilization stability was optimal (1.84%) when the opening degree of fertilizer discharging device was 30.42 mm and the rotational speed of fertilizer discharging shaft was 51.5 r/min. The comparison test showed that the average value of the coefficients of variations of the commonly used spiral organic fertilizer discharger was 6.12%, and the organic fertilizer discharger with scraper conveyor designed in this paper effectively improved the stability of organic fertilizer discharging.Conclusion The designed fertilizer discharging device with scraper conveyor has good fertilizer discharging performance and meets the requirements of organic fertilizer application in greenhouse.

Abstract:Objective In order to solve the problems that the fertilization mode of banana orchard in South China does not meet the agronomic requirements, the fertilization efficiency and the automation level of fertilization machinery are low, a precision fertilization device with automatic target for banana stalk was designed.Method According to the fertilization process and agronomic requirement of banana orchard, the control principle of the device and the installation location of key components were determined, and the time lag model related to fertilization was established. Through the innovative design of the fluted fertilizer distributer, the mathematical models of single cycle and periodic fertilization amount were established, and the motion characteristics of fertilizer were verified by EDEM simulation. In order to meet the fertilizer requirements of banana at different growth stages, the response surface methodology was used to optimize the parameters of fertilizer discharging mechanism. The variation coefficient of fertilization amount, variation coefficient of fertilization length and offset distance from the center of banana stalk were used as the evaluation indexes. Field test was performed using the combination of optimization parameters to further verify the performance of the precision fertilization device.Result The optimal parameters were determined as follows: The rotational speed of fertilizer-distributer shaft was 85 r/min, and the initial length of inner core of fluted roller was 6 mm. The field test showed that the variation coefficients of fertilization amount and fertilization length were both below 4%, and the highest average offset distance from the center of banana stalk was 7.4 cm, meeting the agronomic requirements.Conclusion The working performance of the device can meet the requirements of banana fertilization. This study can provide references for the design of the precision fertilization device for banana orchard.

Abstract:Objective This study was aimed to evaluate the effect of nodes within a green banana bunch harvested in suitable period, inner and outer row layers nested in nodes, fruit finger surface area and impact level on fruit impact bruise susceptibility, providing references for targeted protection to ensure fruit finger quality in subsequent production and handling processes.Method Nested, one-way and orthogonal experimental designs were combined with one-way and multi-way ANOVAs to determine the factors and primary-secondary relationship that significantly affect the bruise susceptibility of fruits. A pendulum impact bench was designed and constructed to carry out the impact damage test on fruits. The bruise susceptibility (bruise volume per unit absorbed energy) of fruits was calculated based on measuring bruise volume and corresponding absorbed energy.Result The results of the nested test showed that the nodes within a banana bunch had no significant effect on the bruise susceptibility while the row layer nested in nodes had an extremely significant effect. The 14 levels of the row layers nested in nodes could be divided into four groups according to the results of multiple comparisons analysis. The results of the one-way test showed that fruit finger surface area had highly significant effect on the bruise susceptibility which was in order of near fruit apex >fruit middle >near fruit pedicel. The bruise susceptibility increased with the increase of impact level. The results of the orthogonal test showed that the order of the factors affecting fruit bruise susceptibility was impact level > growth location> fruit finger surface area.Conclusion The impact bruise susceptibilities were significantly different between inner and outer row layers nested in nodes within a banana bunch, and among different fruit finger surface areas.

Abstract:Objective To develop an automatic navigation system for agricultural machinery based on satellite-based precision single-point precision.Method With the domestic Lovol TX1204 tractor as the platform, the output data of the domestic satellite-based precision single-point positioning board were used as the position feedback of the agricultural machinery, the position-velocity Kalman filter was designed to filter the positioning data, and the preview following PID path tracking control algorithm was developed. The model control parameters under different driving speed conditions were tuned, and the output data of the ground-based RTK high-precision positioning receiver were used as the references, the automatic navigation test system of agricultural machinery was built and the system performance test was carried out.Result In terms of linear tracking error, the average error was ?0.0009436 m, the standard deviation was 0.02452 m, and the absolute maximum error was 0.08472 m. In terms of adjacent line error, the average error was 0.0007128 m, the standard deviation was 0.02986 m, and the absolute maximum error was 0.15444 m, which could meet the needs of most agricultural machinery automatic driving operations.Conclusion Domestic satellite-based precision single-point positioning technology can be used for agricultural machinery automatic navigation. The preview-following PID path tracking control model designed in this paper is valid and the proposed method for tuning PID parameters and foresight distance under different speed conditions provides a basis for improving the adaptive ability of this system to different speed conditions.

Abstract:Objective Virtual assembly can save production cost and improve the production efficiency of mechanical parts in industry. Due to the lack of the function of automatically creating collision body, the existing virtual reality engine can not completely restore the physical properties in the actual assembly process. Universaly building mechanical part grid entity is the important approach for improving practicability, accuracy and universality of virtual assembly.Method The batch preprocessing algorithm and the improved sampling algorithm were designed for the batch agricultural machinery parts sampling. The image data set of three-dimensional model sample was constructed to train the artificial intelligence classification detection network, which can classify and detect the relevant parameters from the image samples, and realize the function of automatic construction of collision body.Result The accuracy of the classification network trained by the optimized algorithm was more than 98% for the classification of parts from pictures, and more than 98% for the construction parameters of collision bodies from pictures. However, the network without optimized training did not converge.Conclusion This method can effectively improve the recognition accuracy and training efficiency of the artificial intelligence classification detection network, and improve the modeling accuracy of the collision body by combining with the collision body parameterization construction program.

Abstract:Objective To propose a whole area coverage strategy of agricultural robot in complex farmland environment, and reasonably plan the working traversal path of agricultural robot.Method The complex farmland working environment model was defined according to the actual production environment of agricultural robot, and the concepts of first-level partition and second-level partition were established. The idea of genetic algorithm mutation operation was introduced to establish a high-quality feasible solution generation method of simulated annealing algorithm based on greedy mechanism. Based on the establishment of the concept of solution set diversity, an improved method of simulated annealing algorithm based on adaptive heating was designed to solve the problem of the optimal traversal sequence between partitions. The A* algorithm was combined with the eight-neighbor search method to plan the cross-regional connection path of agricultural robot. By this way, the scheme designed in this paper could achieve that the robot covered the whole working area.Result The simulation results showed that, compared with the traditional genetic algorithm and simulated annealing algorithm, the path length planned by the improved simulated annealing algorithm was reduced by 14.7% and 10.1% respectively, and the number of iterations during convergence was reduced by 9.8% and 59.1% respectively. The repeating rate of the traversal path of the agricultural robot in the simulation test of whole area coverage was 14.86%. The path repetition rate in the field traversal test of the high ground-clearance spraying robot was 15.83%.Conclusion The research results can provide a research idea for the full traversal coverage of agricultural robot in complex farmland environment.