Fractional Gradient Descent RBFNN for Active Fault-Tolerant Control of Plant Protection UAVs

With the increasing prevalence of high-order systems in engineering applications, these systems often exhibitsignificant disturbances and can be challenging to model accurately. As a result, the active disturbance rejectioncontroller (ADRC) has been widely applied in various fields. However, in controlling plant protection unmannedaerial vehicles (UAVs), which are typically large and subject to significant disturbances, load disturbances andthe possibility of multiple actuator faults during pesticide spraying pose significant challenges. To address theseissues, this paper proposes a novel fault-tolerant control method that combines a radial basis function neuralnetwork (RBFNN) with a second-order ADRC and leverages a fractional gradient descent (FGD) algorithm.We integrate the plant protection UAV model’s uncertain parameters, load disturbance parameters, and actuatorfault parameters and utilize the RBFNN for system parameter identification. The resulting ADRC exhibits loaddisturbance suppression and fault tolerance capabilities, and our proposed active fault-tolerant control law hasLyapunov stability implications. Experimental results obtained using a multi-rotor fault-tolerant test platformdemonstrate that the proposed method outperforms other control strategies regarding load disturbance suppressionand fault-tolerant performance.

Urban Garden Planning and Design and Ornamental Plant Protection

Due to the rapid economic and social development, the quality of life of people has been significantly improved, and peopled demand for living environment has become increasingjy high, which has increased peopled awareness of landscaping. Because of the development of urbankation, however, most cities have lost their balance in the ecological enviionment although they seem to have the modem flavor of life. Integrating garden design with plant protection is an important measure to protect the ecological environment and maintain ecological balance. How to protect the plants in urban garden planning and design has become a problem to be solved by garden designers. In this paper, the relationship between garden design and plant protection was ekbofated, the status quo and problems of ornamental plant protection were analyzed, and measures to protect ornamental plants were proposed.

Particle Kinematics Analysis of Droplet Drift in Spraying Operation of Plant Protection UAV

[Objectives]The paper was to study the effect of droplet drift on spray quality of plant protection UAV.[Methods]Based on the theory of multiphase flow and the method of particle kinematics,the force and motion trajectory of droplet sprayed by plant protection UAV were theoretically analyzed and mathematically modeled.On the basis of the assumption of wind speed in the ground layer and the laminar sublayer,that is,it is assumed that the wind speed in the area of wind measurement was approximately a linear distribution,the coupling iterative solution of the equations was carried out.The influence of droplet diameter,flight height,flight speed of plant protection UAV,course angle,wind speed,wind direction,initial droplet velocity and direction of initial velocity on droplet drift were analyzed.The influence of the coupling effect of each factor on droplet drift was further discussed and the distribution of droplet drift concentration was obtained.[Results]The wind speed and direction had much influence on the drift distance of droplets,and the drift distance and the initial velocity angle show a quadratic function distribution.Under the given conditions,the drift distance was the closest when the initial velocity angle was about 20°.The droplet drift was mainly distributed scatteredly around the nozzle.[Conclusions]The study provides a reference for improving the spraying quality of plant protection UAV.

Plant Protection： The Risk Mitigation of Endocrine Disrupting Pesticides Use Demands the Shared Responsibility of All within the Agricultural System

The widespread use of agrochemicals and its possible negative impacts on humans and the environment remains a highly topical and controversial issue. Of particular concern here are chemicals that can disturb an organism＇s endocrine system. Referring to the precautionary principle, the objective of the research project start2 is to develop management strategies that help reduce possible risks for httmans and the environment of endocrine active agrochemicals. As an empirical basis we combined qualitative and quantitative methods and initiated two expert dialogues. Our findings underpin the well known fact that the use of agrochemicals is complex and dependent on more than the individual attitudes of farmers. Agricultural plant protection management is the collective product of a complex agricultural system, which encompasses treatment, marketing, industry and agricultural consultation as well as agricultural teaching institutions and relevant scientific disciplines. Successful management strategies for risk reduction in the context of hormonally active agrochemicals thus need to involve all actors within this system. The paper proposes a strategy that promotes participation by enabling learning processes among these actors.

Design and Research of Efficient Adaptive Spray Plant Protection UAV

When the plant protection UAV is spraying on plants, the operator usually performs visual inspection on the vertical distance between the UAV and the plant to adjust the spray height to complete the application. Visual inspection by human eyes is easy to cause the error of spray deposition and deposition density. In order to improve the full utilization of drugs and the spraying efficiency of plant protection UAV, an efficient adaptive spray plant protection UAV was designed, and the vertical distance from the UAV to the plant was collected by ultrasonic wave. Meantime, the plant density was detected in real time, and the flight attitude of plant protection UAV and application rate of spray nozzle were automatically adjusted. The experimental results showed that the designed highly efficient adaptive spray plant protection UAV had fast response speed, precise spray location and less drug loss.

Application of MR Technology in Teaching:A Case Study of UAV Agriculture&Forestry Plant Protection Curriculum

In order to solve the problems of insufficient training equipment,relatively lack of curriculum resources and single teaching means in the teaching of UAV(unmanned aerial vehicle)applied technology major,this paper studies the application of MR(Mixed Reality)in UAV applied technology major teaching,with the teaching of UAV agriculture&forestry plant protection curriculum as the carrier.The study will solve the pain points in teaching,improve the teaching ability and teaching information level,and increase the talent training quality of UAV,agriculture&forestry plant protection and related majors.Furthermore,it will create a protective,interactive,remote and scalable teaching experience for stu-dents,which can improve the teaching effect and reduce the teaching cost.

Thoughts on Science and Technology Service in Agricultural Research Institutes:Taking Institute of Plant Protection of Hebei Academy of Agricultural and Forestry Sciences as an Example

Scientific and technological services are necessary for strengthening agriculture.Under the new situation,agricultural research institutes should give full play to their advantages,strive to innovate scientific and technological services methods,and improve scientific and technological service levels.Combined with the practice of science and technology work of Institute of Plant Protection of Hebei Academy of Agricultural and Forestry Sciences,this paper made an in-depth analysis on the present situations and existing problems in the scientific and technological services of agricultural research institutes.Based on the analysis,it came up with recommendations including change ideological concepts,strengthening service awareness,adhering to people-oriented principle,enhancing the team building,improving mechanism construction,stimulating innovative vitality,exploring service methods,and enriching service connotation,so as to improve scientific and technological service works.

The Resistance of Crops in Plant Protection

World crop production requires highly-productive varieties of agricultural crops,which are resistant to pest organisms.Such varieties are also of great importance for the Uzbekistan.Their

A New Exploration of Practical Teaching Reform in the Department of Plant Protection of Hebei North University

In view of the existing problems in the practical teaching of Plant Protection majors,such as more teaching contents,less comprehensive and innovative contents,disorganized practical teaching system,lenient assessment,insufficient experimental teaching facilities,insufficient practical teaching sites,and lack of continuity of practical teaching contents.The practical teaching of plant protection majors should adopt“open”practice teaching methods in terms of laboratory construction,innovative ability cultivation,practical teaching content highlighting comprehensive and innovative,and practical teaching time.The results of the survey on college graduates and enterprises show that under the“open”practice mode,Plant Protection students will have better overall performance.

Reform and Research on the Combination of Production and Education in Plant Protection under the Background of Transformation and Development

Plant Protection is an agricultural discipline with strong theoretical and practical significance.In order to adapt to the development direction of the society during the transition period and the need for professional talents,the researchers have discussed the teaching mode of the plant protection major from various perspectives of the teaching practice.Through the integration of teaching content and knowledge the overall structure of the course is being made clearer and reasonable;The use of different teaching methods has stimulated the initiative of students and achieved remarkable teaching results;The creativity and practical ability of students have been significantly improved;And the examination and evaluation system has been improved,thereby students’performance can be truly reflected.Through the reform and research of plant protection industry-academia and practical teaching,a feasible way is proposed for the combination of industry-academia and the cultivation of practical talents.

Mode switching torque distribution strategy of timely four-wheel driven high-gap plant protection machine

The high-gap plant protection machine is taken in this paper as the research object to ensure the good driving power and safety of the high-gap plant protection machine,and the control strategy of inter-shaft torque distribution is established under different working conditions to improve vehicle power and lateral stability.The anticipated demand torque is initially determined based on the structural characteristics and operational principles of the plant protection machine.Subsequently,a hierarchical control framework is devised by incorporating a formulated switching control strategy.Finally,a simulation model for torque distribution control strategy between shafts is developed on the Matlab/Simulink platform,followed by simulation and experimental verification.The results are presented as follows:the inter-shaft torque distribution strategy established in this paper increases the average longitudinal acceleration by 0.13 m/s^(2) and 0.14 m/s^(2) under the control of low and high to low adhesion road surfaces,respectively.Under the control of the single-line shifting condition,the yaw velocity can successfully follow the expected value with a maximum value of 0.61 rad/s.The side deflection angle of the center of mass does not exceed 2.8°,which can follow the ideal trajectory and improve power and safety.

Downwash airflow field distribution characteristics and their effect on the spray field distribution of the DJI T30 six-rotor plant protection UAV

Spray characteristics are the fundamental factors that affect droplet transportation downward,deposition,and drift.The downwash airflow field of the Unmanned Aviation Vehicle(UAV)primarily influences droplet deposition and drift by changing the spray characteristics.This study focused mainly on the effect of the downwash airflow field of the UAV and nozzle position on the droplet spatial distribution and velocity distribution,which are two factors of spray characteristics.To study the abovementioned characteristics,computational fluid dynamics based on the lattice Boltzmann method(LBM)was used to simulate the downwash airflow field of the DJI T30 six-rotor plant protection UAV at different rotor rotational speeds(1000-1800 r/min).A particle image velocimetry system(PIV)was utilized to record the spray field with the downwash airflow field at different rotational speeds of rotors(0-1800 r/min)or different nozzle positions(0,0.20 m,0.35 m,and 0.50 m from the motor).The simulation and experimental results showed that the rotor downwash airflow field exhibited the‘dispersion-shrinkage-redispersion’development rule.In the initial dispersion stage of rotor airflow,there were obvious high-vorticity and low-vorticity regions in the rotor downwash airflow field.Moreover,the low-vorticity region was primarily concentrated below the motor,and the high-vorticity region was mainly focused in the middle area of the rotors.Additionally,the Y-direction airflow velocity fluctuated at 0.4-1.2 m under the rotor.When the rotor airflow developed to 3.2 m below the rotor,the Y-direction airflow velocity showed a slight decrease.Above 3.2 m from the rotor,the Y-direction airflow velocity started to drastically decrease.Therefore,it is recommended that the DJI T30 plant protection UAV should not exceed 3.2 m in flight height during field spraying operations.The rotor downwash airflow field caused the nozzle atomization angle,droplet concentration,and spray field width to decrease while increasing the vortex scale in the spray field when the rotor system was activated.Moreover,the increase in rotor rotational speed promoted the abovementioned trend.When the nozzle was installed in various radial locations below the rotor,the droplet spatial distribution and velocity distribution were completely different.When the nozzle was installed directly below the motor,the droplet spatial distribution and velocity distribution were relatively symmetrical.When the nozzle was installed at 0.20 m and 0.35 m from the motor,the droplets clearly moved toward the right under the induction of stronger rotor vortices.This resulted in a higher droplet concentration in the right-half spray field.However,the droplet moved toward the left when the nozzle was installed in the rotor tip.For four nozzle positions,when the nozzle was installed at 0 or 0.20 m from the motor,the droplet average velocity was much higher.However,the droplet average velocity was slower when the nozzle was installed in the other two positions.Therefore,it is recommended that the nozzle is installed at 0 or 0.20 m from the motor.The research results could increase the understanding of the downwash airflow field distribution characteristics of the UAV and its influence on the droplet spatial distribution and velocity distribution characteristics.Meanwhile,the research results could provide some theoretical guidance for the choice of nozzle position below the rotor.

Review of Plant Essential Oils for Plant Pests Management

This paper reviews the origins and classification of plant essential oil resources,along with prevalent extraction techniques for their active constituents.By integrating insights on the utilization of plant essential oils for plant pest management,the comprehensive analysis reveals multiple functionalities exhibited by plant essential oils,including fumigation,contact toxicity,repellent action,antifeedant activity,and growth inhibition.Furthermore,the paper highlights the challenges associated with plant essential oils in plant protection and outlines future research directions,aiming to offer valuable insights for the advancement of botanical insecticides.

Recent development of unmanned aerial vehicle for plant protection in East Asia

Recently,the growing use of unmanned aerial vehicles(UAV)for pesticide application has been reported against a wide range of crops with promising results in East Asian countries such as Japan,South Korea and China.This UAV-based application technology for agrochemicals is considered as a high efficiency alternative to the conventional manual spray operations and a low-cost choice as compared to the classical manned aerial application.However,the technology adoption rate and the designed optimal sprayer suitable for drone application for small scale farm remains at the development stage in China and also in Japan.This paper reports the current status of drone pesticide application in China and makes comparisons with its neighbor countries Japan and South Korea in terms of different UAV platforms and their implementation in plant protection for different crops.Challenges and opportunities for future development of UAV-based pesticide application technology are also discussed.

Review of agricultural spraying technologies for plant protection using unmanned aerial vehicle(UAV)

With changing climate and farmland ecological conditions,pest outbreaks in agricultural landscapes are becoming more frequent,increasing the need for improved crop production tools and methods.UAV-based agricultural spraying is anticipated to be an important new technology for providing efficient and effective applications of crop protection products.This paper reviews and summarizes the status of the current research and progress on UAV application technologies for plant protection,and it discusses the characteristics of atomization by unmanned aircraft application systems with a focus on spray applications of agrichemicals.Additionally,the factors influencing the spraying performance including downwash airflow field and operating parameters are analyzed,and a number of key technologies for reducing drift and enhancing the application efficiency such as remote sensing,variable-rate technologies,and spray drift models are considered.Based on the reviewed literature,future developments and the impacts of these UAV technologies are projected.This review may inspire the innovation of the combined use of big data analytics and UAV technology,precision agricultural spraying technology,drift reduction technology,swarm UAV cooperative technology,and other supporting technologies for UAV-based aerial spraying for scientific research in the world.

Effects of plant protection UAV-based spraying on the vertical distribution of droplet deposition on Japonica rice plants in Northeast China

In order to study the regularity of the vertical distribution of droplet deposition on rice plants during pesticide spraying operated by a low-flying multi-rotor plant protection unmanned aviation vehicle(UAV),water-sensitive spray cards were placed on the leaves at the top,in the middle,and at the bottom of rice plants to acquire data on droplet deposition.In this study,a suspension containing tricylazole and hexaconazole was used in the spraying.The water-sensitive spray cards were analyzed by the droplet deposition processing software iDAS to obtain the vertical distribution of the droplets sprayed by the plant protection UAV.The results showed that (1)significant variation was found in the coverage of the droplets in different vertical positions of the rice plants.Within the effective spray width,the best coverage of the droplets was found in the area just below the rotors,whereas the coverage of areas farther away from the rotors was poor.For the different vertical positions of the rice plants,the overall droplet coverage was 58.38%at the top,33.55%in the middle,and 11.34%at the bottom of the plants;(2)for all vertical positions,the average size of the droplets ranged between 110μm and 140μm,which was suitable for the control of plant diseases and insect pests.The highest droplet density was found at the top of the plants,and the distribution of the droplet density was similar in the middle and at the bottom of the rice plants;(3)the diffusion ratio at the top of the rice plants(0.84)was better than that in the middle(0.57)and at the bottom(0.37).The overall relative span could meet the requirements for the actual application.Except for the position in the middle of the plants,the relative span for the other positions of the plants was over 0.67,which is the standard value.This study demonstrated the distribution regularity of droplet deposition along with the vertical direction of rice plants during UAV-based spraying,which is of guiding significance for the use of UAVs in plant protection,the improvement of chemical utilization efficiency,and the reduction of pesticide and fertilizer pollution.

Intelligent automated system based on a fuzzy logic system for plant protection product control in orchards

The spraying of plant protection product(PPP)in orchards is a very hazardous working procedure,owing to the spray drift caused by the uneven operation of conventional axial boom sprayers.This research describes an intelligent automated system for precise(PPP)distribution in real-time.It is based on an intelligent decision-making model using ultrasonic measurements of leaf area density under laboratory conditions,which serve to trigger electromagnetic valves(EMV)on the axial boom sprayer.A fuzzy logic algorithm was an integrated part of the intelligent system for controlling the PPP by generating the pulse width modulation signal and applying it through the EMV of the prototype boom sprayer.The results showed that by using an intelligent decision-making model,the same efficiency as with conventional methods could be achieved,but with reduced usage of plant protection products.Thus,the intelligent automated system used 4.8 times less spray mixture than the conventional one.

Distribution regularity of downwash airflow under rotors of agricultural UAV for plant protection

In the plant protection spray operation of UAVs,the process of droplet from formation to sedimentation target is affected by airflow,easy to form uneven deposition.Accurately description of rotor downwash flow field,clarification of velocity vector distribution at different heights of the UAV rotor flow field,simulation of the flow field with high precision,which are the prerequisites for accurately analyzing the droplet deposition distribution in rotor downwash flow field.Based on CFD method,the detail of rotor flow field was numerically calculated.Taking LTH-100 single-rotor agricultural UAV as the research object,the three-dimensional solid model of UAV was established,the Reynolds average N-S equation was used as the control equation and the RNGκ-εas the turbulence model to simulate the flow field of UAV in hover and lateral wind conditions,the wind velocity distribution at different altitudes of rotor downwash flow field was studied.The simulation results of the hover state showed that:In the flow field,the peak velocity appears in a circular distribution below the distal axis of the rotor.With the decrease of height,the peak velocity distribution area showed a tendency to expand gradually after small shrinkage;When the distance from the rotor was not more than 1.5 m,the downwash flow field presented an axisymmetric distribution based on the rotor axis,and the variation rate of velocity in the peak velocity was basically the same,turbulence in downwash flow field made the flow field more complex when the distance from rotor was larger than 2.0 m.On this basis,the optimal flight altitude of UAV is 1.5 m.Wind velocity test of the flow field was carried out on a rotor test bench,wind velocities at four altitudes of 0.5 m,1.0 m,1.5 m and 2.0 m were measured to verify the coincidence between the simulated and measured values.The test results showed that:the relative error between the measured and simulated values at four measurement heights were between 0.382-0.524,and the overall average relative errors was 0.430,which verified the confidence level of simulated values for measured values.When the lateral wind velocity was 3 m/s,4 m/s and 5 m/s,the simulation results showed that:The distribution trend of airflow velocity at the same altitude in lateral-wind flow field with different wind speeds was similar;When the lateral wind speed was 5 m/s,the coupling field formed by the lateral wind and rotor airflow cannot reach the height of 2 m below the rotor.The results of this study can provide more accurate environmental conditions for theoretical analysis of droplet deposition regularity in the flow field,and also provide methodological guidance for the related research on rotor flow field of multi-rotor UAV.

Plant Variety Protection and DUS Testing Technique

DUS testing technique used for plant variety protection was reviewed in the paper, and some suggestions were made on how to establish the appropriate technology system in China. Meanwhile, the potential exploitation of the technique was discussed.