Implantable bioelectronics for analyzing physiological biomarkers has recently been recognized as a promising technique in medical treatment or diagnostics. In this study, we developed a self-powered implantable skinl...Implantable bioelectronics for analyzing physiological biomarkers has recently been recognized as a promising technique in medical treatment or diagnostics. In this study, we developed a self-powered implantable skinlike glucometer for real-time detection of blood glucose level in vivo. Based on the piezo-enzymatic-reaction coupling effect of GOx@ZnO nanowire, the device under an applied deformation can actively output piezoelectric signal containing the glucose-detecting information. No external electricity power source or battery is needed for this device, and the outputting piezoelectric voltage acts as both the biosensing signal and electricity power. A practical application of the skin-like glucometer implanted in mouse body for detecting blood glucose level has been simply demonstrated. These results provide a new technique path for diabetes prophylaxis and treatment.展开更多
The increasing morbidity of internal diseases poses serious threats to human health and quality of life.Exhaled breath analysis is a noninvasive and convenient diagnostic method to improve the cure rate of patients. I...The increasing morbidity of internal diseases poses serious threats to human health and quality of life.Exhaled breath analysis is a noninvasive and convenient diagnostic method to improve the cure rate of patients. In this study, a self-powered breath analyzer based on polyaniline/polyvinylidene fluoride(PANI/PVDF) piezogas-sensing arrays has been developed for potential detection of several internal diseases. The device works by converting exhaled breath energy into piezoelectric gassensing signals without any external power sources. The five sensing units in the device have different sensitivities to various gas markers with concentrations ranging from 0 to 600 ppm. The working principle can be attributed to the coupling of the in-pipe gas-flow-induced piezoelectric effect of PVDF and gas-sensing properties of PANI electrodes. In addition, the device demonstrates its use as an ethanol analyzer to roughly mimic fatty liver diagnosis.This new approach can be applied to fabricating new exhaled breath analyzers and promoting the development of self-powered systems.展开更多
We fabricated wearable perspiration analyzing sites for actively monitoring physiological status during exercises without any batteries or other power supply.The device mainly consists of ZnO nanowire(NW)arrays and fl...We fabricated wearable perspiration analyzing sites for actively monitoring physiological status during exercises without any batteries or other power supply.The device mainly consists of ZnO nanowire(NW)arrays and flexible polydimethylsiloxane substrate.Sweat on the skin can flow into the flow channels of the device through capillary action and flow along the channels to ZnO NWs.The sweat flowing on the NWs(with lactate oxidase modification)can output a DC electrical signal,and the outputting voltage is dependent on the lactate concentration in the sweat as the biosensing signal.ZnO NWs generate electric double layer(EDL)in sweat,which causes a potential difference between the upper and lower ends(hydrovoltaic effect).The product of the enzymatic reaction can adjust the EDL and influence the output.This device can be integrated with wireless transmitter and may have potential application in constructing sports big data.This work promotes the development of next generation of biosensors and expands the scope of self-powered physiological monitoring system.展开更多
Combining multiple crop protection Unmanned Aerial Vehicles(UAVs)as a team for a scheduled spraying mission over farmland now is a common way to significantly increase efficiency.However,given some issues such as diff...Combining multiple crop protection Unmanned Aerial Vehicles(UAVs)as a team for a scheduled spraying mission over farmland now is a common way to significantly increase efficiency.However,given some issues such as different configurations,irregular borders,and especially varying pesticide requirements,it is more important and more complex than other multi-Agent Systems(MASs)in common use.In this work,we focus on the mission arrangement of UAVs,which is the foundation of other high-level cooperations,systematically propose Efficiency-first Spraying Mission Arrangement Problem(ESMAP),and try to construct a united problem framework for the mission arrangement of crop protection UAVs.Besides,to characterise the differences in sub-areas,the varying pesticide requirement per unit is well considered based on Normalized Difference Vegetation Index(NDVI).Firstly,the mathematical model of multiple crop-protection UAVs is established and ESMAP is defined.Furthermore,an acquisition method of a farmland’s NDVI map is proposed,and the calculation method of pesticide volume based on NDVI is discussed.Secondly,an improved Genetic Algorithm(GA)is proposed to solve ESMAP,and a comparable combination algorithm is introduced.Numerical simulations for algorithm analysis are carried out within MATLAB,and it is determined that the proposed GA is more efficient and accurate than the latter.Finally,a mission arrangement tested with three UAVs was carried out to validate the effectiveness of the proposed GA in spraying operation.Test results illustrated that it performed well,which took only 90.6%of the operation time taken by the combination algorithm.展开更多
Spray boom vibrations are one of the main causes of the uneven distribution of agrochemicals.Using active suspension to maintain the correct height of nozzles is critical for obtaining a uniform spray pattern and mini...Spray boom vibrations are one of the main causes of the uneven distribution of agrochemicals.Using active suspension to maintain the correct height of nozzles is critical for obtaining a uniform spray pattern and minimizing the possibility of spray drift.However,the electro-hydraulic active pendulum boom suspension has nonlinear uncertain factors such as parameter uncertainties,external disturbances,model error,etc.,which complicate the design of the controller.Therefore,this paper proposes a nonlinear robust feedback control method with disturbances compensation,which integrates a robust controller and disturbance observers through the backstepping method.Initially,to verify the performance of the controller,the Lyapunov stability theory is used to prove that the proposed controller can guarantee the given transient performance and the final tracking accuracy.Furthermore,taking the active suspension of a 28 m wide boom driven by a single-rod hydraulic actuator as an implementation case,the proposed NRCDC controller was compared with a variety of control schemes through a rapid control prototype of a pendulum active suspension.Finally,the proposed control scheme is implemented on a self-propelled sprayer with a boom of 12 m in length.The field test results show that all the performance indicators of the NRCDC controller are better than the other three conventional controllers.Both laboratory and field tests have verified the effectiveness and high performance of the proposed controller.展开更多
Pesticide dose model based on canopy characteristics is the guidance basis for spray parameters adjustment.In this study,the calculation formula and canopy deposition characteristics of leaf wall area(LWA)model,tree r...Pesticide dose model based on canopy characteristics is the guidance basis for spray parameters adjustment.In this study,the calculation formula and canopy deposition characteristics of leaf wall area(LWA)model,tree row volume(TRV)model,and optimal coverage method(OCM)model were described and compared.A tower air-assisted spray test bench was applied to provide fine quality droplets,suitable wind speed and demand spray flow rate for corresponding models,an electric flat board vehicle was applied to drive tree in a straight line to simulate the sprayer movement speed,and droplet deposition distribution were tested in different leaf area density canopy.The results showed that the spray flow rates of three pesticide dose models decreased gradually.LWA model was only related to canopy height,TRV model was related to canopy height and canopy diameter,while OCM model was related to canopy height,canopy diameter and leaf area density.Whether dense or sparse canopy,TRV model basically satisfied the requirement of coverage rate greater than 33%in the entire canopy,OCM model met the requirement of coverage density greater than 70 droplets/cm^(2).However,LWA model,for dense canopy,unit area deposition of outermost leaves near sprayer was 3.6 times of the apple leaf maximum retention,which had a high loss risk;for sparse canopy,penetration rates of outermost leaves far away sprayer,that is,the drift rate was 21.4%.The discussion leads to the conclusion that for conventional spraying,TRV model represented a substantial improvement compared to LWA model,and OCM model was a reasonable low volume spraying model.This study provides a reference to different growth seasons spray amount adjustments in orchard.展开更多
Small unmanned aerial vehicle(UAV),a timely and effective pesticide sprayer,can be used to spray pesticide in a high efficiency without harming the crop,and is especially suitable for spraying for small farms and hill...Small unmanned aerial vehicle(UAV),a timely and effective pesticide sprayer,can be used to spray pesticide in a high efficiency without harming the crop,and is especially suitable for spraying for small farms and hills in Asian countries.In recent years,it has been chosen as a key and new technique for pesticide application.This paper studied the impact of UAV(UAV N-3)spraying parameters(different working height and different spraying concentrations)on the deposition of droplets on the wheat canopy and the prevention of powdery mildew.Water sensitive paper was used as the sampler to collect the pesticide droplets and image processing software Deposit Scan was used to compute the coverage rate of droplets on the wheat top layer to acquire the proportional distribution of droplets on the wheat lower layer.The experimental results showed the impact of spraying height on the distribution of droplets on the wheat upper layer was quite significant,when the spraying height was 5.0 m and the spraying speed was 4 m/s,the coverage rate of droplets on the wheat lower layer was the largest,as it was 45.6%of that on the upper layer,the droplets distribution was the most uniform,and the coefficient of variation was 33.13%.450 g/hm^(2)(dosage registered)of triadimefon SC(44%)was sprayed by the UAV,the control efficiency reached 55.1%after applying which was better than 20%and 40%of dosage decreased for each hectare,and the applying effect(35.6%)of 20%dosage decreased for each hectare had no significant difference from the applying effect(34.6%)applied by a knapsack-type electric sprayer.At 10 d after applying,the prevention effect realized by UAV was lower than that realized by a knapsack-type electric sprayer,and it may be correlated to the meteorological condition and water amount in the pesticide sprayed.Thus,when UAV spraying was chosen to prevent wheat powdery mildew under a serious disease situation,an auxiliary agent for spraying could be added to prolong the retention of pesticide on the plant surface to extend the pesticide effect.This study can provide a reference for the optimized design,performance upgrade and reasonable application of small UAV sprayers.展开更多
Spray deposit distribution from a field sprayer is mainly affected by the boom movements when the tractor is driven over a rough soil surface,the pendulum suspension that used to reduce and control the movement of spr...Spray deposit distribution from a field sprayer is mainly affected by the boom movements when the tractor is driven over a rough soil surface,the pendulum suspension that used to reduce and control the movement of spray boom by isolating the boom from vibrations of the tractor will directly enhance uniform deposition of chemicals.However,how to match the parameters of the suspension with the properties of the boom is the key problem.The dynamic rigid-flexible coupling model of the virtual prototype of the spray boom suspension system was established by using ADAMS and ABAQUS software.An optimization of the suspension parameters for a large spay boom was carried out based on the optimal Latin hypercube design,radial basis function neural network,and multi-objective genetic algorithm NSGA-II.After modified parameters of the suspension,the travel of the sprayer on a typical field motion track was simulated based on a six DOF motion simulator,and the dynamic behavior of the boom suspension was measured.The results show that RMS of the measured boom roll angle and the boom center displacement for optimized solution were reduced by 14.76%and 12.43%compared with the original suspension.Finally,the inertial measurement unit(IMU)was used to measure the movements of the sprayer vehicle during the pesticide application on the Hongze Lake Farm,the experiment of field condition reproduced by using the six DOF motion simulator,the standard deviation of the roll angle and vibration displacement for the optimized sprayer boom are only 0.6382°and 62.279 mm respectively.The research provides theoretical basis and experimental method for parameter optimization of large scale boom suspension.展开更多
A self-charging hybrid power unit has been developed by integrating a water-evaporation-induced nano- generator with a flexible nano-patterned supercapacitor. The nanogenerator can harvest environmental thermal energy...A self-charging hybrid power unit has been developed by integrating a water-evaporation-induced nano- generator with a flexible nano-patterned supercapacitor. The nanogenerator can harvest environmental thermal energy and mechanical energy through the water evaporation process, and the supercapacitor can be charged simultaneously. The former offers stable electrical power as output, whereas the Ppy- based supercapacitor shows a capacitance of 12.497 m F/cm^2 with 96.42% retention after 4,000 cycles. After filling the power unit with water as the fuel, it can be fully charged in about 20 min. The power unit can be flexibly integrated with electronic devices such as sensor nodes and wireless transmitters employ- ing the Internet of Things. This new approach can offer new possibilities in continuous future operation of randomly distributed electronic devices incorporated in the Internet of Things.展开更多
A new self-powered active gas sensor for realtime monitoring of automotive exhaust gas was devised.The pipe-shaped device was fabricated from polydimethylsiloxane/polypyrrole(PDMS/Ppy)triboelectric gas-sensing unit ar...A new self-powered active gas sensor for realtime monitoring of automotive exhaust gas was devised.The pipe-shaped device was fabricated from polydimethylsiloxane/polypyrrole(PDMS/Ppy)triboelectric gas-sensing unit arrays.The gas-sensing units can actively convert the mechanical energy of gas flow into a triboelectric current.The output current signal depends on the species and concentrations of the target chemical gases(CO,NH3,NO)in the gas flow,and thus can be used as a sensing signal.The device consists of seven gas-sensing units with different Ppy derivatives.As the different sensing units respond to the gases in different ways,the device can differentiate between gas species.The working mechanism is attributed to the coupling effect between the triboelectric effect of PDMS/Ppy and the gas-sensing properties of Ppy.The device can be installed in the tailpipe of an automobile,and can thus analyze the exhaust gas in real time without the need for any external electrical power.The results of the present study spur a new research direction for the development of automotive exhaust gas monitoring systems,thus playing an important role in the detection of air pollution.展开更多
Unmanned aerial vehicle(UAV)has the advantages of good repeatability and high remote sensing(RS)information acquisition efficiency,as an important supplement bridging the gap of high-altitude and ground RS platforms.A...Unmanned aerial vehicle(UAV)has the advantages of good repeatability and high remote sensing(RS)information acquisition efficiency,as an important supplement bridging the gap of high-altitude and ground RS platforms.A quadrotor UAV was developed for the agricultural RS application in this study.The control system consists of a main processor and a coprocessor,integrating a three-axis gyroscope,a three-axis accelerometer,an air pressure sensor and a global positioning system(GPS)module.Engineering trial method(ETM)was used to tune the parameters based on the active disturbance rejection control(ADRC)method.Also a ground control station(GCS)adapted to the quadrotor was developed realizing autonomously take-off and landing,flight route planning,data recording.To investigate the performances of the UAV,several flight tests were carried out.The test results showed that the pitch angle control accuracy error was less than 4°,the flight height control accuracy error was less than 0.86 m,the flight path control accuracy error was less than 1.5 m overall.Aerial multispectral images were acquired and processed.The reflected digital number(DN)values obtained from a height of 10-100 m with 10 m interval could be referenced to classify objects.The normalized-difference-vegetation index(NDVI)values obtained from the aerial multispectral images acquired at 15 m were compared with those obtained by the GreenSeeker(GS)and PSR-1100F.The maximum error was 20.37%while the minimum error was 1.99%,which demonstrated the developed quadrotor UAV’s satisfactions for low altitude remote sensing practice.This study provided a low-cost platform for agricultural remote sensing.展开更多
Boom sprayer is one of the most commonly used plant protection machinery for spraying pesticide.Studies have shown that the efficiency of chemicals is highly correlated with the uniformity of spray distribution patter...Boom sprayer is one of the most commonly used plant protection machinery for spraying pesticide.Studies have shown that the efficiency of chemicals is highly correlated with the uniformity of spray distribution patterns.As the boom is a large and flexible structure,boom rolling leads to overlapping and leakage of the pesticides.In order to improve spray uniformity,the boom attitude should be kept parallel to the ground slope or to the crop canopy beneath the boom.Passive suspension can attenuate frequencies above its resonance frequency,but nothing can be done to align the boom to the sloping ground.Therefore,an active suspension system is designed,which includes DSP-based controller,a servo valve,a hydraulic cylinder,two ultrasonic sensors,one inertial attitude sensor,and the developed control procedures.In order to prevent the wrong response of the control system caused by the high frequency component due to uneven crop canopy or rough ground.A special signal processing algorithm was proposed,including the limiting filter,smoothing algorithm and data fusion algorithm based on optimal weight.The transient and steady-state performances of the boom control system using velocity feedforward PID algorithm were tested on a six DOF motion simulator.It can be seen that the low-frequency tracking performance of the boom was greatly improved after the electro-hydraulic active suspension was added.At the resonance frequency,the peak angle of active suspension and passive suspensions are 0.72°and 1.29°respectively,and the resonance peak is greatly reduced.The controller was implemented on a self-propelled boom sprayer and validated under field conditions,the standard deviation of the roll angle of the boom with active suspension is 0.40°,compared with 1.04°of the sprayer chassis.Experimental results show that the active suspension control system can effectively reduce the effect of ground excitation disturbance on the application process,and has good tracking performance for low frequency terrain change.展开更多
A new self-powered temperature-sensitive electronic-skin(e-skin) for real-time monitoring body temperature without external electricity power was fabricated from patterned polydimethylsiloxane/polyaniline(PDMS/PANI) n...A new self-powered temperature-sensitive electronic-skin(e-skin) for real-time monitoring body temperature without external electricity power was fabricated from patterned polydimethylsiloxane/polyaniline(PDMS/PANI) nanostructures. The e-skin can be feasibly attached on the human body and driven by the mechanical motion energy through triboelectric effect. The outputting triboelectric impulse of the PDMS/PANI units is significantly dependent on the local surface temperature of the eskin, serving as both the power source and temperature sensing signal. The outputting current of the e-skin increases with increasing surface temperature of the device. Under applied bending deformation,the response of the e-skin is up to 63.6 for 38.6℃. The e-skin can detect minimum temperature change of 0.4℃. The working mechanism can be ascribed to the coupling effect of triboelectric and semiconductor properties(tribotronic effect). A practical application of the e-skin attaching on the human body for detecting the body temperature range of 36.5–42.0℃ has been simply demonstrated. This work provides a viable method for real-time monitoring body temperature, and can promote the development of wearable temperature sensors and self-powered multifunctional nanosystems.展开更多
A new self-powered/self-cleaned atmosphere monitoring system has been fabricated from TiO_(2)nanoparticles through combining hydrovoltaic,gas sensing and photocatalytic effects.The TiO_(2)nanoparticle film can convert...A new self-powered/self-cleaned atmosphere monitoring system has been fabricated from TiO_(2)nanoparticles through combining hydrovoltaic,gas sensing and photocatalytic effects.The TiO_(2)nanoparticle film can convert natural thermal energy into electricity(hydrovoltaic effect)by the spontaneous water evaporation.The hydrovoltaic/gas-sensing coupling effect of TiO_(2)nanoparticle offers the waterevaporation-powered gas detection performance,and the outputting voltage/current has a good response to the surrounding gas atmosphere,directly acting as the gas sensing signal.The zeta potential of TiO_(2)is changed by the surface adsorption of gas molecules,and thus affects the electricity output of the system.The outputting electricity can directly power a wireless transmitter for transmitting the sensing information to external platform,and the whole system can work independently without electricity power supply.The rainwater can be used as the fuel of the system,and thus the system can be used outdoors without scheduled maintenance.Moreover,the photocatalytic activity of TiO_(2)can effectively degrade the organic pollutants on the film under photo illumination,leading to a self-clean behavior of the system.The system can probably promote the development of green sensing techniques with evaporation-induced ability.展开更多
Proper nozzles arrangement is significant to improve spray deposition of crop protection unmanned aerial system(UAS).Besides fuselage structure,the control strategy is another nozzle location changing method when ther...Proper nozzles arrangement is significant to improve spray deposition of crop protection unmanned aerial system(UAS).Besides fuselage structure,the control strategy is another nozzle location changing method when there are multiple sets of nozzles.A four-rotor crop protection UAS equipped with four centrifugal nozzles was used to conduct a field experiment in the rupturing stage of rice.Two sets of nozzles in the front and rear of the fuselage were enabled independently to investigate spray deposition,including spray coverage and droplet density on the sampling cards.Various nozzle rotating speeds and flight speeds were employed in the experiment to study the influence of nozzle location on the deposition.With different nozzle rotating speeds,the droplet spectrum could be controlled.The results show that the average coverage and average cumulative droplet density are negatively correlated with flight speed.Average droplet density is also negatively correlated with the droplet size.Spray deposition of front nozzles is significantly reduced compared with that of the rear nozzles under the same spray parameters,especially when the droplet size is too large or the flight speed is too fast.The reduction is mainly concentrated in the center area of the spray swath.As a result,the average cumulative droplet density of the front nozzles decreases by 25.96%in total.The average droplet density decreases by 18.54%when the droplet size is smaller than 100μm,decreases by 25.02%when between 100μm and 200μm,and decreases by more than half when larger than 200μm.This research can provide guidance for the installation of UAS nozzles and spray control strategy design.展开更多
The effective swath width(ESW)and the droplet penetration rate(DPR)directly affect the spraying quality,the spraying efficiency and the control effect of pests and diseases during the crop protection unmanned aircraft...The effective swath width(ESW)and the droplet penetration rate(DPR)directly affect the spraying quality,the spraying efficiency and the control effect of pests and diseases during the crop protection unmanned aircraft system(CPUAS)application.However,the ESW and DPR are not constant with the changes of the flight speed(FS)and the flight height(FH).In order to investigate the ESW and DPR of the CPUAS P20,four levels of FS(3 m/s,4 m/s,5 m/s and 6 m/s)and three levels of FH(1.5 m,2.0 m and 2.5 m)experiments were carried out according to the first industry standard of China for the CPUAS in the wheat field.The results demonstrated that the ESWs were negatively correlated with the FS and the FH.Most of the ESWs were over 2 m in the 12 treatments,in which the maximum one was 3.25 m(3 m/s,1.5 m).The DPRs were negatively correlated with the FH under the same FS,the average value of the DPRs was 48.37%,in which the maximum one was 78.34%(4 m/s,1.5 m)and the minimum one was 25.5%(6.0 m/s,2.5 m).The statistical analyses showed that the FS had significant impacts on the ESWs(0.01<p-value<0.05)while there were no significant differences among different FH treatments(p-value>0.05).The impacts of both FS and FH on the DPRs were extremely significant(p-value<0.01),and the interactive impacts were significant(0.01<p-value<0.05).Therefore,it is concluded that reducing the FS could increase the ESWs,and reducing the FH could increase the DRPs at the same FS.In conclusion,the maximum spraying efficiency of P20 was 4.342 hm2/h with 6 m/s FS and 1.5 m FH in case of satisfying the requirement of DPRs.This study provided scientific references for guiding the CPUAS spraying.展开更多
As a new type of crop protection machine,the crop protection unmanned aerial system(CPUAS)is developing rapidly in China.The wind field generated by the rotor has a great influence on the deposition and penetration of...As a new type of crop protection machine,the crop protection unmanned aerial system(CPUAS)is developing rapidly in China.The wind field generated by the rotor has a great influence on the deposition and penetration of spraying droplets.The purpose of this study was to develop a reliable and stable test platform that could be used for wind field test of CPUAS,and to carry out the downwash experiments on the platform to obtain the downwash distribution law of a CPUAS Z-3N(100 kg level,Nanjing Research Institute on Simulation Technique,Nanjing,China).The tests showed that the performances of the developed platform could meet the expected design requirements.The platform operated stably and reliably during the downwash experiments of Z-3N,which indicated it could be applied for CPUASs of 100 kg level and below.The vibration characteristics of the platform with different heights(2.0 m,3.0 m,5.0 m,7.0 m,10.0 m)were obtained through modal analysis,which could effectively guide avoiding the resonance for stable and reliable operation during the experiments with the tested CPUAS Z-3N.A ring-radial method was designed combined with the platform for the downwash measurement.The experimental results showed that the downwash distribution of Z-3N was not symmetrical;the downwash wind speed decreased with the increase of the radial distance while the changing trend was not consistent as the height increased.Moreover,the area with high wind speed was mainly within 3.0 m of the radial distance,and the maximum value was 11.37 m/s.The study provided a new way for wind field test of CPUASs and would provide some references for better utilization of wind field during the CPUAS spraying.展开更多
Application of Unmanned Aircraft Systems(UAS)for plant protection is becoming a common tool in agricultural field management.To avoid shortcomings of intrusive flowrate sensors including poor measurement accuracy and ...Application of Unmanned Aircraft Systems(UAS)for plant protection is becoming a common tool in agricultural field management.To avoid shortcomings of intrusive flowrate sensors including poor measurement accuracy and poor anti-vibration ability,a non-intrusive flowrate measurement and monitoring system of plant-protection UAS was developed based on pump voice signal analysis.It is mainly composed of STM32 processor,microphone and signal-conditioning circuit.By collecting and analyzing the voice signal of the pump in the UAS,the monitoring system will output the real-time values of spraying flowrate and amount.An extraction model was developed to determine operation status and primary frequency of the pump based on voice signal analysis.Real-time spray flowrate can be determined from the real-time extracted primary frequency and the fitted correlation formulas of spraying flowrate under outlet area and pump primary frequency.The flowrate correlation equation of one certain pump from 4-rotor UAS 3WQFTX-1011S was obtained,the max deviation rate of fitted spray flowrate was only 2.8%.In primary frequency extraction test,the error rate of primary frequency extraction was less than 1%.In the 4-rotor UAS flight tests:the max deviation of operating starting/end point was only 0.7 s and the max deviation of extracted total operating time was only 0.8 s;the deviation of extracted spray flowrate was less than 2%,and the max deviation rate of total spray amount was 3.2%.This research could be used as a guidance for plant-protection UAS non-intrusive flowrate measurement and monitoring.展开更多
基金supported by the National Natural Science Foundation of China (11674048)the Fundamental Research Funds for the Central Universities (N160502002)Liaoning BaiQianWan Talents Program (2014921017)
文摘Implantable bioelectronics for analyzing physiological biomarkers has recently been recognized as a promising technique in medical treatment or diagnostics. In this study, we developed a self-powered implantable skinlike glucometer for real-time detection of blood glucose level in vivo. Based on the piezo-enzymatic-reaction coupling effect of GOx@ZnO nanowire, the device under an applied deformation can actively output piezoelectric signal containing the glucose-detecting information. No external electricity power source or battery is needed for this device, and the outputting piezoelectric voltage acts as both the biosensing signal and electricity power. A practical application of the skin-like glucometer implanted in mouse body for detecting blood glucose level has been simply demonstrated. These results provide a new technique path for diabetes prophylaxis and treatment.
基金supported by the National Natural Science Foundation of China (11674048)the Fundamental Research Funds for the Central Universities (N170505001 and N160502002)Program for Shenyang Youth Science and Technology Innovation Talents (RC170269)
文摘The increasing morbidity of internal diseases poses serious threats to human health and quality of life.Exhaled breath analysis is a noninvasive and convenient diagnostic method to improve the cure rate of patients. In this study, a self-powered breath analyzer based on polyaniline/polyvinylidene fluoride(PANI/PVDF) piezogas-sensing arrays has been developed for potential detection of several internal diseases. The device works by converting exhaled breath energy into piezoelectric gassensing signals without any external power sources. The five sensing units in the device have different sensitivities to various gas markers with concentrations ranging from 0 to 600 ppm. The working principle can be attributed to the coupling of the in-pipe gas-flow-induced piezoelectric effect of PVDF and gas-sensing properties of PANI electrodes. In addition, the device demonstrates its use as an ethanol analyzer to roughly mimic fatty liver diagnosis.This new approach can be applied to fabricating new exhaled breath analyzers and promoting the development of self-powered systems.
基金supported by the National Natural Science Foundation of China(11674048)Sichuan Science and Technology Program(20JCQN0201).
文摘We fabricated wearable perspiration analyzing sites for actively monitoring physiological status during exercises without any batteries or other power supply.The device mainly consists of ZnO nanowire(NW)arrays and flexible polydimethylsiloxane substrate.Sweat on the skin can flow into the flow channels of the device through capillary action and flow along the channels to ZnO NWs.The sweat flowing on the NWs(with lactate oxidase modification)can output a DC electrical signal,and the outputting voltage is dependent on the lactate concentration in the sweat as the biosensing signal.ZnO NWs generate electric double layer(EDL)in sweat,which causes a potential difference between the upper and lower ends(hydrovoltaic effect).The product of the enzymatic reaction can adjust the EDL and influence the output.This device can be integrated with wireless transmitter and may have potential application in constructing sports big data.This work promotes the development of next generation of biosensors and expands the scope of self-powered physiological monitoring system.
基金the China Postdoctoral Science Foundation Grant(2019M661912)Major Scientific and Technological Innovation Projects in Shandong Province(2019JZZY020616)+1 种基金Opening Foundation of Key Laboratory of Modern Agricultural Equipment(Ministry of Agriculture and Rural Affairs),the Project of Scientific Research and Development of the University in Shandong Province(J18KA128)Cotton innovation team of Shandong modern agricultural industry technology system(SDAIT-03-09).
文摘Combining multiple crop protection Unmanned Aerial Vehicles(UAVs)as a team for a scheduled spraying mission over farmland now is a common way to significantly increase efficiency.However,given some issues such as different configurations,irregular borders,and especially varying pesticide requirements,it is more important and more complex than other multi-Agent Systems(MASs)in common use.In this work,we focus on the mission arrangement of UAVs,which is the foundation of other high-level cooperations,systematically propose Efficiency-first Spraying Mission Arrangement Problem(ESMAP),and try to construct a united problem framework for the mission arrangement of crop protection UAVs.Besides,to characterise the differences in sub-areas,the varying pesticide requirement per unit is well considered based on Normalized Difference Vegetation Index(NDVI).Firstly,the mathematical model of multiple crop-protection UAVs is established and ESMAP is defined.Furthermore,an acquisition method of a farmland’s NDVI map is proposed,and the calculation method of pesticide volume based on NDVI is discussed.Secondly,an improved Genetic Algorithm(GA)is proposed to solve ESMAP,and a comparable combination algorithm is introduced.Numerical simulations for algorithm analysis are carried out within MATLAB,and it is determined that the proposed GA is more efficient and accurate than the latter.Finally,a mission arrangement tested with three UAVs was carried out to validate the effectiveness of the proposed GA in spraying operation.Test results illustrated that it performed well,which took only 90.6%of the operation time taken by the combination algorithm.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFD2000700)Fundamental Research Funds for Central Research Institutes of China(Grant No.Y2022XK31)+1 种基金R&D projects in key areas of Guangdong Province(Grant No.2019B0202221001)Jiangsu Modern Agricultural Machinery Equipment and Technology Demonstration and Promotion Project(Grant No.NJ2022-01).
文摘Spray boom vibrations are one of the main causes of the uneven distribution of agrochemicals.Using active suspension to maintain the correct height of nozzles is critical for obtaining a uniform spray pattern and minimizing the possibility of spray drift.However,the electro-hydraulic active pendulum boom suspension has nonlinear uncertain factors such as parameter uncertainties,external disturbances,model error,etc.,which complicate the design of the controller.Therefore,this paper proposes a nonlinear robust feedback control method with disturbances compensation,which integrates a robust controller and disturbance observers through the backstepping method.Initially,to verify the performance of the controller,the Lyapunov stability theory is used to prove that the proposed controller can guarantee the given transient performance and the final tracking accuracy.Furthermore,taking the active suspension of a 28 m wide boom driven by a single-rod hydraulic actuator as an implementation case,the proposed NRCDC controller was compared with a variety of control schemes through a rapid control prototype of a pendulum active suspension.Finally,the proposed control scheme is implemented on a self-propelled sprayer with a boom of 12 m in length.The field test results show that all the performance indicators of the NRCDC controller are better than the other three conventional controllers.Both laboratory and field tests have verified the effectiveness and high performance of the proposed controller.
基金This research was funded by Special Fund for Basic Scientific Research Business of Chinese Academy of Agricultural Sciences(Grant No.S202112-02)Crop Protection Machinery Team(Grant No.CAAS-ASTIP-CPMT)+1 种基金China Modern Agricultural Industrial Technology System(Grant No.CARS-12)Collaborative Innovation Project of Scientific and Technological Innovation Projec to fChines eAcadem yo fAgricultura lScience s(Gran tNo.CAAS-XTCX 201823).
文摘Pesticide dose model based on canopy characteristics is the guidance basis for spray parameters adjustment.In this study,the calculation formula and canopy deposition characteristics of leaf wall area(LWA)model,tree row volume(TRV)model,and optimal coverage method(OCM)model were described and compared.A tower air-assisted spray test bench was applied to provide fine quality droplets,suitable wind speed and demand spray flow rate for corresponding models,an electric flat board vehicle was applied to drive tree in a straight line to simulate the sprayer movement speed,and droplet deposition distribution were tested in different leaf area density canopy.The results showed that the spray flow rates of three pesticide dose models decreased gradually.LWA model was only related to canopy height,TRV model was related to canopy height and canopy diameter,while OCM model was related to canopy height,canopy diameter and leaf area density.Whether dense or sparse canopy,TRV model basically satisfied the requirement of coverage rate greater than 33%in the entire canopy,OCM model met the requirement of coverage density greater than 70 droplets/cm^(2).However,LWA model,for dense canopy,unit area deposition of outermost leaves near sprayer was 3.6 times of the apple leaf maximum retention,which had a high loss risk;for sparse canopy,penetration rates of outermost leaves far away sprayer,that is,the drift rate was 21.4%.The discussion leads to the conclusion that for conventional spraying,TRV model represented a substantial improvement compared to LWA model,and OCM model was a reasonable low volume spraying model.This study provides a reference to different growth seasons spray amount adjustments in orchard.
基金supported by the National Key Research and Development Plan(2016YFD0200700)Natural Science Foundation of Jiangsu Province,China(BK20151074)+1 种基金the Pesticide Applying Intelligent Operating System based on Beidou Automatic Navigation by UAV(1610372016008)the Chinese Academy of Agricultural Sciences Special Basic Scientific Research Business Expenses(Y2017PT32).
文摘Small unmanned aerial vehicle(UAV),a timely and effective pesticide sprayer,can be used to spray pesticide in a high efficiency without harming the crop,and is especially suitable for spraying for small farms and hills in Asian countries.In recent years,it has been chosen as a key and new technique for pesticide application.This paper studied the impact of UAV(UAV N-3)spraying parameters(different working height and different spraying concentrations)on the deposition of droplets on the wheat canopy and the prevention of powdery mildew.Water sensitive paper was used as the sampler to collect the pesticide droplets and image processing software Deposit Scan was used to compute the coverage rate of droplets on the wheat top layer to acquire the proportional distribution of droplets on the wheat lower layer.The experimental results showed the impact of spraying height on the distribution of droplets on the wheat upper layer was quite significant,when the spraying height was 5.0 m and the spraying speed was 4 m/s,the coverage rate of droplets on the wheat lower layer was the largest,as it was 45.6%of that on the upper layer,the droplets distribution was the most uniform,and the coefficient of variation was 33.13%.450 g/hm^(2)(dosage registered)of triadimefon SC(44%)was sprayed by the UAV,the control efficiency reached 55.1%after applying which was better than 20%and 40%of dosage decreased for each hectare,and the applying effect(35.6%)of 20%dosage decreased for each hectare had no significant difference from the applying effect(34.6%)applied by a knapsack-type electric sprayer.At 10 d after applying,the prevention effect realized by UAV was lower than that realized by a knapsack-type electric sprayer,and it may be correlated to the meteorological condition and water amount in the pesticide sprayed.Thus,when UAV spraying was chosen to prevent wheat powdery mildew under a serious disease situation,an auxiliary agent for spraying could be added to prolong the retention of pesticide on the plant surface to extend the pesticide effect.This study can provide a reference for the optimized design,performance upgrade and reasonable application of small UAV sprayers.
基金This study was financially supported by the National Key Research and Development Program of China(2016YFD0200705)the National Natural Science Foundation of China(Grant No.51605236)the Independent Innovation Fund of Agricultural Science and Technology of Jiangsu Province(CX(16)1043).
文摘Spray deposit distribution from a field sprayer is mainly affected by the boom movements when the tractor is driven over a rough soil surface,the pendulum suspension that used to reduce and control the movement of spray boom by isolating the boom from vibrations of the tractor will directly enhance uniform deposition of chemicals.However,how to match the parameters of the suspension with the properties of the boom is the key problem.The dynamic rigid-flexible coupling model of the virtual prototype of the spray boom suspension system was established by using ADAMS and ABAQUS software.An optimization of the suspension parameters for a large spay boom was carried out based on the optimal Latin hypercube design,radial basis function neural network,and multi-objective genetic algorithm NSGA-II.After modified parameters of the suspension,the travel of the sprayer on a typical field motion track was simulated based on a six DOF motion simulator,and the dynamic behavior of the boom suspension was measured.The results show that RMS of the measured boom roll angle and the boom center displacement for optimized solution were reduced by 14.76%and 12.43%compared with the original suspension.Finally,the inertial measurement unit(IMU)was used to measure the movements of the sprayer vehicle during the pesticide application on the Hongze Lake Farm,the experiment of field condition reproduced by using the six DOF motion simulator,the standard deviation of the roll angle and vibration displacement for the optimized sprayer boom are only 0.6382°and 62.279 mm respectively.The research provides theoretical basis and experimental method for parameter optimization of large scale boom suspension.
基金supported by the National Natural Science Foundation of China(11674048)the Fundamental Research Funds for the Central Universities(N170505001,and N160502002)Program for Shenyang Youth Science and Technology Innovation Talents(RC170269)
文摘A self-charging hybrid power unit has been developed by integrating a water-evaporation-induced nano- generator with a flexible nano-patterned supercapacitor. The nanogenerator can harvest environmental thermal energy and mechanical energy through the water evaporation process, and the supercapacitor can be charged simultaneously. The former offers stable electrical power as output, whereas the Ppy- based supercapacitor shows a capacitance of 12.497 m F/cm^2 with 96.42% retention after 4,000 cycles. After filling the power unit with water as the fuel, it can be fully charged in about 20 min. The power unit can be flexibly integrated with electronic devices such as sensor nodes and wireless transmitters employ- ing the Internet of Things. This new approach can offer new possibilities in continuous future operation of randomly distributed electronic devices incorporated in the Internet of Things.
基金supported by the National Natural Science Foundation of China (11674048)the Fundamental Research Funds for the Central Universities (N170505001 and N160502002)the Program for Shenyang Youth Science and Technology Innovation Talents (RC170269)
文摘A new self-powered active gas sensor for realtime monitoring of automotive exhaust gas was devised.The pipe-shaped device was fabricated from polydimethylsiloxane/polypyrrole(PDMS/Ppy)triboelectric gas-sensing unit arrays.The gas-sensing units can actively convert the mechanical energy of gas flow into a triboelectric current.The output current signal depends on the species and concentrations of the target chemical gases(CO,NH3,NO)in the gas flow,and thus can be used as a sensing signal.The device consists of seven gas-sensing units with different Ppy derivatives.As the different sensing units respond to the gases in different ways,the device can differentiate between gas species.The working mechanism is attributed to the coupling effect between the triboelectric effect of PDMS/Ppy and the gas-sensing properties of Ppy.The device can be installed in the tailpipe of an automobile,and can thus analyze the exhaust gas in real time without the need for any external electrical power.The results of the present study spur a new research direction for the development of automotive exhaust gas monitoring systems,thus playing an important role in the detection of air pollution.
基金This research was financially supported by the National Natural Science Foundation of China(No.31701327)the National Key Research and Development Program of China(Grant NO.2017YFD0701000)Collaborative Innovation Plan of Scientific and Technological Innovation Project(Grant No.CAAS-XTCX2016006).
文摘Unmanned aerial vehicle(UAV)has the advantages of good repeatability and high remote sensing(RS)information acquisition efficiency,as an important supplement bridging the gap of high-altitude and ground RS platforms.A quadrotor UAV was developed for the agricultural RS application in this study.The control system consists of a main processor and a coprocessor,integrating a three-axis gyroscope,a three-axis accelerometer,an air pressure sensor and a global positioning system(GPS)module.Engineering trial method(ETM)was used to tune the parameters based on the active disturbance rejection control(ADRC)method.Also a ground control station(GCS)adapted to the quadrotor was developed realizing autonomously take-off and landing,flight route planning,data recording.To investigate the performances of the UAV,several flight tests were carried out.The test results showed that the pitch angle control accuracy error was less than 4°,the flight height control accuracy error was less than 0.86 m,the flight path control accuracy error was less than 1.5 m overall.Aerial multispectral images were acquired and processed.The reflected digital number(DN)values obtained from a height of 10-100 m with 10 m interval could be referenced to classify objects.The normalized-difference-vegetation index(NDVI)values obtained from the aerial multispectral images acquired at 15 m were compared with those obtained by the GreenSeeker(GS)and PSR-1100F.The maximum error was 20.37%while the minimum error was 1.99%,which demonstrated the developed quadrotor UAV’s satisfactions for low altitude remote sensing practice.This study provided a low-cost platform for agricultural remote sensing.
基金We acknowledge that this study was financially supported by the National Key Research and Development Program of China(2017YFD0700905)the National Natural Science Foundation of China(Grant No.51605236)the Synergistic Innovation Center of Jiangsu Modern Agricultural Equipment and Technology(4091600002).
文摘Boom sprayer is one of the most commonly used plant protection machinery for spraying pesticide.Studies have shown that the efficiency of chemicals is highly correlated with the uniformity of spray distribution patterns.As the boom is a large and flexible structure,boom rolling leads to overlapping and leakage of the pesticides.In order to improve spray uniformity,the boom attitude should be kept parallel to the ground slope or to the crop canopy beneath the boom.Passive suspension can attenuate frequencies above its resonance frequency,but nothing can be done to align the boom to the sloping ground.Therefore,an active suspension system is designed,which includes DSP-based controller,a servo valve,a hydraulic cylinder,two ultrasonic sensors,one inertial attitude sensor,and the developed control procedures.In order to prevent the wrong response of the control system caused by the high frequency component due to uneven crop canopy or rough ground.A special signal processing algorithm was proposed,including the limiting filter,smoothing algorithm and data fusion algorithm based on optimal weight.The transient and steady-state performances of the boom control system using velocity feedforward PID algorithm were tested on a six DOF motion simulator.It can be seen that the low-frequency tracking performance of the boom was greatly improved after the electro-hydraulic active suspension was added.At the resonance frequency,the peak angle of active suspension and passive suspensions are 0.72°and 1.29°respectively,and the resonance peak is greatly reduced.The controller was implemented on a self-propelled boom sprayer and validated under field conditions,the standard deviation of the roll angle of the boom with active suspension is 0.40°,compared with 1.04°of the sprayer chassis.Experimental results show that the active suspension control system can effectively reduce the effect of ground excitation disturbance on the application process,and has good tracking performance for low frequency terrain change.
基金supported by the National Natural Science Foundation of China (No. 11674048)
文摘A new self-powered temperature-sensitive electronic-skin(e-skin) for real-time monitoring body temperature without external electricity power was fabricated from patterned polydimethylsiloxane/polyaniline(PDMS/PANI) nanostructures. The e-skin can be feasibly attached on the human body and driven by the mechanical motion energy through triboelectric effect. The outputting triboelectric impulse of the PDMS/PANI units is significantly dependent on the local surface temperature of the eskin, serving as both the power source and temperature sensing signal. The outputting current of the e-skin increases with increasing surface temperature of the device. Under applied bending deformation,the response of the e-skin is up to 63.6 for 38.6℃. The e-skin can detect minimum temperature change of 0.4℃. The working mechanism can be ascribed to the coupling effect of triboelectric and semiconductor properties(tribotronic effect). A practical application of the e-skin attaching on the human body for detecting the body temperature range of 36.5–42.0℃ has been simply demonstrated. This work provides a viable method for real-time monitoring body temperature, and can promote the development of wearable temperature sensors and self-powered multifunctional nanosystems.
基金the National Natural Science Foundation of China(No.11674048)Sichuan Science and Technology Program(2020JDJQ0026)。
文摘A new self-powered/self-cleaned atmosphere monitoring system has been fabricated from TiO_(2)nanoparticles through combining hydrovoltaic,gas sensing and photocatalytic effects.The TiO_(2)nanoparticle film can convert natural thermal energy into electricity(hydrovoltaic effect)by the spontaneous water evaporation.The hydrovoltaic/gas-sensing coupling effect of TiO_(2)nanoparticle offers the waterevaporation-powered gas detection performance,and the outputting voltage/current has a good response to the surrounding gas atmosphere,directly acting as the gas sensing signal.The zeta potential of TiO_(2)is changed by the surface adsorption of gas molecules,and thus affects the electricity output of the system.The outputting electricity can directly power a wireless transmitter for transmitting the sensing information to external platform,and the whole system can work independently without electricity power supply.The rainwater can be used as the fuel of the system,and thus the system can be used outdoors without scheduled maintenance.Moreover,the photocatalytic activity of TiO_(2)can effectively degrade the organic pollutants on the film under photo illumination,leading to a self-clean behavior of the system.The system can probably promote the development of green sensing techniques with evaporation-induced ability.
基金This research was supported by the National Key Research and Development Program of China(Grant No.2017YFD0701000)the Science and Technology Development Plan of Suzhou(Grant No.SNG2020042)+1 种基金China Agriculture Research System of MOF and MARA(Grant No.CARS-12)and the Special Expenses for Basic Scientific Research of Chinese Academy of Agricultural Sciences(Grant No.SR201903).
文摘Proper nozzles arrangement is significant to improve spray deposition of crop protection unmanned aerial system(UAS).Besides fuselage structure,the control strategy is another nozzle location changing method when there are multiple sets of nozzles.A four-rotor crop protection UAS equipped with four centrifugal nozzles was used to conduct a field experiment in the rupturing stage of rice.Two sets of nozzles in the front and rear of the fuselage were enabled independently to investigate spray deposition,including spray coverage and droplet density on the sampling cards.Various nozzle rotating speeds and flight speeds were employed in the experiment to study the influence of nozzle location on the deposition.With different nozzle rotating speeds,the droplet spectrum could be controlled.The results show that the average coverage and average cumulative droplet density are negatively correlated with flight speed.Average droplet density is also negatively correlated with the droplet size.Spray deposition of front nozzles is significantly reduced compared with that of the rear nozzles under the same spray parameters,especially when the droplet size is too large or the flight speed is too fast.The reduction is mainly concentrated in the center area of the spray swath.As a result,the average cumulative droplet density of the front nozzles decreases by 25.96%in total.The average droplet density decreases by 18.54%when the droplet size is smaller than 100μm,decreases by 25.02%when between 100μm and 200μm,and decreases by more than half when larger than 200μm.This research can provide guidance for the installation of UAS nozzles and spray control strategy design.
基金This research was supported by the National Key Research and Development Program of China(Grant No.2017YFD0701000)the National Natural Science Foundation of China(No.31701327)+1 种基金Jiangsu Agriculture Science and Technology Innovation Fund(CX(17)1002)Collaborative Innovation Plan of Scientific and Technological Innovation Project(Grant No.CAAS-XTCX2016006).
文摘The effective swath width(ESW)and the droplet penetration rate(DPR)directly affect the spraying quality,the spraying efficiency and the control effect of pests and diseases during the crop protection unmanned aircraft system(CPUAS)application.However,the ESW and DPR are not constant with the changes of the flight speed(FS)and the flight height(FH).In order to investigate the ESW and DPR of the CPUAS P20,four levels of FS(3 m/s,4 m/s,5 m/s and 6 m/s)and three levels of FH(1.5 m,2.0 m and 2.5 m)experiments were carried out according to the first industry standard of China for the CPUAS in the wheat field.The results demonstrated that the ESWs were negatively correlated with the FS and the FH.Most of the ESWs were over 2 m in the 12 treatments,in which the maximum one was 3.25 m(3 m/s,1.5 m).The DPRs were negatively correlated with the FH under the same FS,the average value of the DPRs was 48.37%,in which the maximum one was 78.34%(4 m/s,1.5 m)and the minimum one was 25.5%(6.0 m/s,2.5 m).The statistical analyses showed that the FS had significant impacts on the ESWs(0.01<p-value<0.05)while there were no significant differences among different FH treatments(p-value>0.05).The impacts of both FS and FH on the DPRs were extremely significant(p-value<0.01),and the interactive impacts were significant(0.01<p-value<0.05).Therefore,it is concluded that reducing the FS could increase the ESWs,and reducing the FH could increase the DRPs at the same FS.In conclusion,the maximum spraying efficiency of P20 was 4.342 hm2/h with 6 m/s FS and 1.5 m FH in case of satisfying the requirement of DPRs.This study provided scientific references for guiding the CPUAS spraying.
基金This research was financially supported by the National Key Research and Development Program of China(Grant No.2017YFD0701000)the National Natural Science Foundation of China(Grant No.31701327)+3 种基金the China Agriculture Research System of MOF and MARA(Grant No.CARS-12)the Agricultural Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences,Crop Protection Machinery Team(Grant No.CAAS-ASTIP-CPMT)the Jiangsu Science and Technology Development Plan(Grant No.BE2019305)the Science and Technology Development Plan of Suzhou,Jiangsu Province(Grant No.SNG2020042).
文摘As a new type of crop protection machine,the crop protection unmanned aerial system(CPUAS)is developing rapidly in China.The wind field generated by the rotor has a great influence on the deposition and penetration of spraying droplets.The purpose of this study was to develop a reliable and stable test platform that could be used for wind field test of CPUAS,and to carry out the downwash experiments on the platform to obtain the downwash distribution law of a CPUAS Z-3N(100 kg level,Nanjing Research Institute on Simulation Technique,Nanjing,China).The tests showed that the performances of the developed platform could meet the expected design requirements.The platform operated stably and reliably during the downwash experiments of Z-3N,which indicated it could be applied for CPUASs of 100 kg level and below.The vibration characteristics of the platform with different heights(2.0 m,3.0 m,5.0 m,7.0 m,10.0 m)were obtained through modal analysis,which could effectively guide avoiding the resonance for stable and reliable operation during the experiments with the tested CPUAS Z-3N.A ring-radial method was designed combined with the platform for the downwash measurement.The experimental results showed that the downwash distribution of Z-3N was not symmetrical;the downwash wind speed decreased with the increase of the radial distance while the changing trend was not consistent as the height increased.Moreover,the area with high wind speed was mainly within 3.0 m of the radial distance,and the maximum value was 11.37 m/s.The study provided a new way for wind field test of CPUASs and would provide some references for better utilization of wind field during the CPUAS spraying.
基金The research was supported by National Key R&D Program of China(Grant No.2017YFD0701000,2018YFD0200900)China Agriculture Research System of MOF and MARA(Grant No.CARS-12)Chinese Academy of Agricultural Sciences Fundamental Research Funds(Grant No.SR201903).
文摘Application of Unmanned Aircraft Systems(UAS)for plant protection is becoming a common tool in agricultural field management.To avoid shortcomings of intrusive flowrate sensors including poor measurement accuracy and poor anti-vibration ability,a non-intrusive flowrate measurement and monitoring system of plant-protection UAS was developed based on pump voice signal analysis.It is mainly composed of STM32 processor,microphone and signal-conditioning circuit.By collecting and analyzing the voice signal of the pump in the UAS,the monitoring system will output the real-time values of spraying flowrate and amount.An extraction model was developed to determine operation status and primary frequency of the pump based on voice signal analysis.Real-time spray flowrate can be determined from the real-time extracted primary frequency and the fitted correlation formulas of spraying flowrate under outlet area and pump primary frequency.The flowrate correlation equation of one certain pump from 4-rotor UAS 3WQFTX-1011S was obtained,the max deviation rate of fitted spray flowrate was only 2.8%.In primary frequency extraction test,the error rate of primary frequency extraction was less than 1%.In the 4-rotor UAS flight tests:the max deviation of operating starting/end point was only 0.7 s and the max deviation of extracted total operating time was only 0.8 s;the deviation of extracted spray flowrate was less than 2%,and the max deviation rate of total spray amount was 3.2%.This research could be used as a guidance for plant-protection UAS non-intrusive flowrate measurement and monitoring.