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.

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.

Root structure of slope protection plants in a high-grade highway

Root length and root length density of Lespedeza bicolor,Amorpha fruticosa,and Sea buckthorn were investigated in a country highway-TongSan highway（Tongjiang to Sanya） in Heilongjiang Province,China.The root lengths were divided into five root orders according to Pregizter sequence classification method.Results show that sea buckthorn roots are dominated by coarse roots in the horizontal growth,while L.bicolor has a large proportion of fine roots in vertical conical growth and A.fruticosa is in depth growth.Root length density of L.bicolor in all the root sequences is higher than that of sea buckthorn and A.fruticosa.On the basis of the root structure,it is inferred that L.bicolor roots mainly absorb the surface soil moisture for its normal growth;in contrast,A.fruticosa has good uptake ability to deep soil water.The root structure of sea buckthorn implies that it has a strong drought resistance.

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.

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.

Impact of Implementing 1991 Act of the International Convention for the Protection of New Varieties of Plants in China

The Union for the Protection of New Varieties of Plants is abbreviated as UPOV. The Convention for the Protection of New Varieties of Plants has 1961/1972 Act ,1978 Act and 1991 Act. China is member of UPOV and its regulations of protection of new varieties of plants conform to 1978 Act. At present, there is big debate whether China accedes to 1991 Act. This paper mainly discussed advantages and possibilities that China accedes to 1991 Act, and concluded that it is highly desirable that China should consider acceding to 1991 Act in order to contribute to development of system on protection of new varieties of plants.

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.

Review of Studies on Rare Earth against Plant Disease

Agricultural application of rare earth (RE) has been generalized for several decades, and it is involved in crops, vegetables and stock raising in China. However, all the researches on RE mainly focus on the fields such as plant physiological activity, physiological and biochemical mechanism, sanitation toxicology and environmental security. Plant protection by using RE and the induced resistance of plant against diseases were summarized. The mechanism of rare earth against plant disease is highlighted, which includes following two aspects. First, RE elements can control some phytopathogen directly and reduce its virulence to host plant. Another possibility is that RE elements can affect host plant and induce the plant to produce some resistance to disease.

Preparation of the UPOV Guidelines for the Conduct of Tests for Distinctness, Uniformity and Stability–Tea Plant [Camellia sinensis (L.) O. Kuntze]

Distinctness, Uniformity and Stability （DUS） testing is the technical base of Plant Variety Protection （PVP） and the scientific basis for the approval of Plant Breeder＇s Rights （PBR）. DUS Test Guidelines are not only the technical manuals for the DUS testing authorities to conduct the testing, but also the technical standards for the competent authorities to examine the DUS of new varieties of plants. Tea plant, originated from Yunnan Province, China, is a very important woody cash species in the world. The International Union for the Protection of New Varieties of Plants （UPOV） DUS Test Guidelines for tea plant is the first Test Guidelines prepared by China for the UPOV. In this article, the subject, selection, and determination of characteristics, states of expression of characteristics and the selection of example varieties, assessment of the UPOV DUS Test Guidelines for tea plant were elucidated in detail. Finally, the proposal of PVP for tea plant in China was also proposed. The preparation of UPOV DUS Test Guidelines for tea plant will have important significance both for promoting the development of PVP and increasing the status of international PVP fields for China.

Research progress of plant antimicrobial peptides

Plant antimicrobial peptides are a very large family of antimicrobial peptides,which have strong resistance to various pathogenic microorganisms,especially fungi.With the increasing use of antibiotics,the problems caused by antibiotics,including antibiotic residues and pathogen resistance,are becoming more and more prominent.The research on antimicrobial peptides as new antibiotic substitutes is also a hot spot.This article introduces the action sites and antibacterial mechanisms of several plant antimicrobial peptides,as well as the application of plant antimicrobial peptides in the fields of medicine,agriculture,and food preservation.

Influence of seven levels of chemical/biostimulator protection on amino acid profile and yield traits in wheat

Biostimulators combined with pesticides can reduce the need for chemical crop protection to yield healthy wheat with high grain quality and nutritional value.The goal of this four-year field study was an assessment of the effects of seven levels of sulfonylurea herbicide,morpholine and triazole fungicides,and humic biostimulator protection on concentrations of 20 amino acids(AAs)and on yield parameters under diverse climatic conditions.Application of pesticides and biostimulators reduced amino acid concentrations.Sulfonylurea applied alone reduced AAs least.Chemical(herbicide+fungicide)protection or its combination with humic biostimulator were the most effective strategies for increasing yield,thousand-kernel weight,spike number,grain surface area,and wet gluten.Reduced dosages of fungicides showed effects on AA content and crop parameter values similar to those of the recommended dosages of fungicides and are in line with the European Commission’s “From Farm to Fork”strategy.Humic biostimulators as agents supporting pesticide protection should be optimized for wheat growth stage to achieve the most desirable wheat parameters and implemented in agricultural practice.

The Register and Characteristics of Chinese Key Protected Wild Plants in Dabie Mountains National Nature Preserve, Hubei Province

A study was conducted on the newly promulgated key protected wild plants distributed in the Dabie Mountains National Nature Reserve in Hubei in 2021.According to statistics,Dabie Mountains National Nature Reserve of Hubei Province has a total of 41 species of wild plants under national key protection,including 7 species in the first class and 34 species in the second class.Among them,6 are cultivated species,4 in the first class,and 2 species in the second class.The characteristics of Chinese key protected wild plants in the Dabie Mountains National Nature Reserve in Hubei Province were analyzed.

Development and Evaluation of an Optical Sensing System for Detection of Herbicide Spray Droplets

Real time monitoring of herbicide spray droplet drift is important for crop production management and environmental protection. Existing spray droplet drift detection methods, such as water-sensitive paper and tracers of fluorescence and Rubidium chloride, are time-consuming and laborious, and the accuracies are not high in general. Also, the tracer methods indirectly quantify the spray deposition from the concentration of the tracer and may change the drift characteristics of the sprayed herbicides. In this study, a new optical sensor system was developed to directly detect the spray droplets without the need to add any tracer in the spray liquid. The system was prototyped using a single broadband programmable LED light source and a near infrared sensor containing 6 broadband spectral detectors at 610, 680, 730, 760, 810, and 860 nm to build a detection system for monitoring and analysis of herbicide spray droplet drift. A rotatory structure driven by a stepper motor in the system was created to shift the droplet capture line going under the optical sensor to measure and collect the spectral signals that reflect spray drift droplets along the line. The system prototype was tested for detection of small (Very Fine and Fine), medium (Medium), and large (Coarse) droplets within the droplet classifications of the American Society of Agricultural and Biological Engineers. Laboratory testing results indicated that the system could detect the droplets of different sizes and determine the droplet positions on the droplet capture line with 100% accuracy at the wavelength of 610 nm selected from the 6 bands to detect the droplets.

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.