Recently, multi-rotor unmanned aerial vehicle (UAV) becomes more and significantly irreplaceable in the field of plant protection against diseases, pests weeds crops. The easy takeoff landing performance, hover function high spraying efficiency UAV are urgently required to spray pesticide for crop timely effectively, especially dispersed plots hilly mountains. In such situations, current researches about application mainly focus on studying influence parameters droplet deposition, as...

In recent years, multirotor unmanned aerial vehicles (UAVs) have become more and important in the field of plant protection China. Multirotor UAVs been widely used vast plains, hills, mountains, other regions, an integral part China’s agricultural mechanization modernization. The easy takeoff landing performances are urgently required for timely effective spraying, especially dispersed plots hilly mountains. However, unclearness wind distribution leads to serious droplet drift problems....

Abstract In this article, committed to extending the robust integral of sign error (RISE) feedback control working condition output feedback, a novel controller with continuously bounded input which combines adaptive and will be proposed for trajectory tracking family nonlinear systems subject modeling uncertainties. A state observer (ASO) disturbance rejection performance is creatively constructed derive real‐time estimation unmeasured signals. Moreover, projection‐type adaption law...

The four-rotor plant protection Unmanned Aerial Vehicle (UAV) is an important piece of equipment for the efficient field. However, flight-coupled wind field unclear, which has become bottleneck factor limiting improvement spray quality. When multi-rotor UAV flew and sprayed, liquid droplets were accelerated, stems branches shaken, leaves turned over in disturbance area spiral backward field, crop canopy closely related. Only when was analyzed could interaction mechanism among droplets, be...

Analysing the penetration and droplet deposition characteristics in canopy of fruit trees is critical for optimising operational parameters air-assisted spraying equipment, achieving precise application chemicals, improving effectiveness tree pest disease control. We used a mobile LIDAR system to detect optical porosity conduct wind tunnel experiments investigate interaction between canopy, airflow field, ratio trees. The results show that relative velocity decreases rapidly during...

Recently, multi-rotor unmanned aerial vehicle (UAV) becomes more and significantly irreplaceable in the field of plant protection against diseases, pests weeds crops. The easy takeoff landing performance, hover function high spraying efficiency UAV are urgently required to spray pesticide for crop timely effectively, especially dispersed plots hilly mountains. In such situations, current researches about application mainly focus on studying influence parameters droplet deposition, as...

Committed to further enhancing the achievable tracking performance, a novel disturbance-compensation-based composite multilayer neural network adaptive control algorithm is developed for class of multiple input output nonlinear systems with modeling uncertainties. Specially, an extended state observer utilized estimate exogenous disturbance and meanwhile predict system state. Moreover, function uncertainties are approximated by networks. Furthermore, can be compensated in feedforward manner....

摘要: 在高压气动热力学过程中,压力远大于临界压力、温度远偏离对应的玻义耳温度,基于理想气体的热力学参数失去真实性,气动性能的品质就无法保证。针对高压空气弹射发射系统,基于对应态方程和改进的维里方程,建立气动方程组,进行真实的动态热力学研究。推导高压空气的余函数的解析表达式,获得温度、压力大幅度变化条件下的真实热物性质参数。利用余函数对动态过程中热物参数的不确定性进行反馈补偿,数值求解气动方程组。对比的数值结果表明,弹射过程余比焓的值偏高,工质状态远远偏离理想气体;弹射过程工质压缩性强,最大压缩因子达1.101 3;真实气体效应增加高压室中压力、温度下降的速率,降低低压室压力、温度上升的速率;高压空气真实的做功能力偏低,但过载平稳。

In this article, the motion control problem of hydraulic lifting systems subject to parametric uncertainties, unmodeled disturbances, and a valve dead-zone is studied. To surmount problem, an active disturbance rejection adaptive controller was developed for systems. Firstly, dynamics, including both mechanical dynamics actuator with system, were modeled. Then, by adopting system model backstepping technique, composite parameter adaptation law extended state observer successfully combined,...

Multi-rotor plant protection Unmanned Aerial Vehicles (UAVs) have suitable terrain adaptability and efficient ultra-low altitude spraying capacity, which is a significant development direction in equipment. The interaction mechanisms of the wind field, droplet, crop are unclear, become bottleneck factor restricting improvement deposition quality. This paper suggests method to study influence pesticide load on detailed distribution law downwash for six-rotor UAV. Based hexahedral structured...

Abstract It is still an open and challenging issue to the typical position control problems of three‐axis electrical‐optical gyro‐stabilized platform systems (TEOGSP), due inherent characteristics, for example, measurement noise, input saturation, parametric uncertainties, largely unknown load disturbance. To solve this problem, a saturated adaptive robust feedback controller using cascaded extended state observer (SAFCESO) proposed compromising between noise effect sensitivity disturbances....

Abstract In this article, a desired compensation version of the output feedback controller (DOFCESO) without using velocity measurement signal is proposed for precise tracking control three‐axis electrical‐optical gyro‐stabilized platform in presence largely unknown matched and mismatched modeling uncertainties. The takes into account not only system parametric deviations as well unmeasurable external disturbances. To further handle disturbances, composite extended state observer nonlinear...

This brief focuses on the motion control issue for uncertain robotic manipulators with unknown nonlinear dynamics and exogenous disturbances simultaneously via output position measurement only. In detail, extended state observer is employed to obtain estimations of immeasurable system information lumped simultaneously. Meanwhile, multilayer neural network good approximation performance incorporated into observer-controller scheme identify dynamics. As a result, both large strong can be...

In this work, by adopting dynamic mesh technology along with the spring based smoothing method and laying zone moving method, we have numerically solved axisymmetric N-S equations, analyzed flow field mechanism thermal shock characteristics, identified environment evaluating influencing factors that are essential for dealing problems in decision making of new land-based concentric canister launcher (CCL) under high-speed load condition, determined evaluation index environment. The mathematic...

A novel transient heat flux sensor (THFS) was developed to measure the of an explosive driven shock tube. The working principle THFS is based on transverse Seebeck effect (TSE) a single crystal Bi 2 Te 3 . has rise time 51 μs and sensitivity up 69.8 μV/(kW/m ), with no signal amplifier required for huge test. This allows highly time-resolved measurements in explosion field, thereby supporting study thermal damage explosion.

Abstract In view of the poor thermodynamic environment problem self-powered launch land-based concentric canister launcher (CCL), launching scheme injecting water at bottom tube is adopted to improve system fundamentally. The solution program for liquid vaporization compiled and embedded into homogeneous gas–liquid two-phase flow model, source phase corrections momentum equation energy are also performed, then three-dimensional fluid dynamics model established CCL; analysis shows that...

Means of predicting aerothermodynamic characteristics turbines and expanders with gas-wet steam working medium having condensation release latent heat vaporization during expansion process are studied. After discussing the basic relations fundamental equations such process, a simple method is suggested on basis introducing concept replacing condensing thermodynamically by an equivalent polytropic index.n. By replacement usual gas calculation program could be used performance prediction...