Chemical Control of Ceratovacuna lanigera Zehntner with Multi-rotor Unmanned Aerial Vehicle

[Objective] The paper was to explore chemical control of Ceratovacuna lanigera Zehntner with multi-rotor unmanned aerial vehicle. [Method] According to the outbreak characteristics of C. lanigera,multi-rotor unmanned aerial vehicle was applied for flying control test. Referred to the spraying characteristics of multi-rotor unmanned aerial vehicle,two kinds of microcapsule pesticides,ALV-1501 and ALV-1502,and two kinds of spraying additives,SPA-01 and SPA-02,were designed to control C. lanigera. [Result] The control effect of ALV-1501 at the dose of 2. 25 L/hm;was 60. 02% at 1 d post administration and 54. 14%at 5 d post administration; the control effects of ALV-1502 at the dose of 2. 1 L/hm2 were 76. 35% and 81. 35% at 1 and 5 d post administration,respectively.Compared to individual pesticide,the control effects of ALV-1501 were improved 1. 42-1. 47 times and 1. 16-1. 14 times by adding 0. 6 L/hm;SPA-01 and SPA-02 in pesticide liquid,respectively. The control effects of ALV-1502 were improved 1. 23-1. 25 times and 1. 15-1. 16 times by adding 0. 6 L/hm2 SPA-01 and SPA-02,respectively. The control effects against C. lanigera at three flying speeds of 3,5 and 8 m/s were 99. 72%-99. 97%,81. 6%-99. 81% and63. 52%-68. 77%,respectively. [Conclusion]The results will provide a reference for application of multi-rotor unmanned aerial vehicle in prevention and control of C. lanigera in sugarcane field.

Control techniques of tilt rotor unmanned aerial vehicle systems： A review

The tilt rotor unmanned aerial vehicle（TRUAV） exhibits special application value due to its unique rotor structure. However, varying dynamics and aerodynamic interference caused by tiltable rotors are great technical challenges and key issues for TRUAV＇s high-powered flight controls, which have attracted the attention of many researchers. This paper outlines the concept of TRUAV and some typical TRUAV platforms while focusing on control techniques. TRUAV structural features, dynamics modeling, and flight control methods are discussed, and major challenges and corresponding developmental tendencies associated with TRUAV flight control are summarized.

Modeling and robust adaptive control for a coaxial twelve-rotor UAV

Compared with the quad-rotor unmanned aerial vehicle (UAV), the coaxial twelve-rotor UAV has stronger load carrying capacity, higher driving ability and stronger damage resistance. This paper focuses on its robust adaptive control. First, a mathematical model of a coaxial twelve-rotor is established. Aiming at the problem of model uncertainty and external disturbance of the coaxial twelve-rotor UAV, the attitude controller is innovatively adopted with the combination of a backstepping sliding mode controller (BSMC) and an adaptive radial basis function neural network (RBFNN). The BSMC combines the advantages of backstepping control and sliding mode control, which has a simple design process and strong robustness. The RBFNN as an uncertain observer, can effectively estimate the total uncertainty. Then the stability of the twelve-rotor UAV control system is proved by Lyapunov stability theorem. Finally, it is proved that the robust adaptive control strategy presented in this paper can overcome model uncertainty and external disturbance effectively through numerical simulation and prototype of twelve-rotor UAV tests.

Analysis of reflected signal of quad rotor UAV based on model fitting in mobile communication system

In view of the many scenes of unmanned aerial vehicle(UAV)detection,a third-party signal source is used to design a receiver to monitor the UAV.It is of great significance to understand the reflection of the signal illuminating the UAV.Taking the communication base station(BS)signal as the third-party signal source,and considering the complete transmission link,reflection changes and loss fading of the communication signal,this study conducts model fitting for irregular UAV targets,simplifying complex targets into a combination of simple targets.Furthermore,the influence of the dielectric constant of the target surface and the signal irradiation angle on the signal reflection is analyzed.The analysis shows that the simulation results of this model fitting method are consistent with the results of other literature,which provides theoretical support for the detection of low and slow small targets such as UAVs.

单旋翼无人机植保作业系统的研制与实验研究

为了提高植保无人机的工作效率,降低无人机的操作难度,研制了单旋翼无人机植保作业系统。根据植保作业流程,单旋翼无人机植保作业系统实现启动、预热、起飞、飞行、喷洒作业、加药和返航等全过程无人工干预的自动飞行作业。单旋翼无人机植保控制系统包括作业平台、飞行控制、数据链路、地面站系统、系统应用、飞行器管理、用户信息管理、专业知识管理、大数据业务,实现了喷洒区域的精准控制,地面站系统与飞行系统的控制与交互,植保信息的存贮与分析等。通过实验研究表明:单旋翼无人机植保作业系统有效提高了植保工作效率,降低了飞行操作人员的操作难度。

具有波浪形桨尖构造的无人机旋翼降噪研究

旋翼作为无人机噪声的重要来源,降低其气动噪声对于提高公众对无人机的接受度具有重要意义。鉴此,提出一种具有波浪形桨尖构造的旋翼设计方案,该方案仅在旋翼桨尖处以特定波浪线型为导线进行放样设计,同时耦合波浪形前缘、波浪形尾缘和波浪表面结构三种特征,该方案可在降低噪声的同时,最大程度保留旋翼气动性能。随后通过计算流体动力学仿真以及试验研究分析波浪形桨尖构造对旋翼气动性能以及气动噪声的影响,揭示其降噪机理,并开展波浪形桨尖参数优化设计。仿真和试验结果表明:具有波浪形桨尖构造的旋翼仍然具有较好的气动性能;在声学性能方面,波浪形桨尖构造降低了旋翼中高频范围内的宽带噪声,其中波形参数N=8的旋翼降噪效果最好,并在旋翼下洗流附近降噪显著,总声压级较Base旋翼下降1.5~4.0 dB。

基于低空视觉的直升机旋翼轴心轨迹测量法

为满足直升机飞行状态旋翼轴心轨迹测量需求,提出了一种基于低空双目视觉的轴心轨迹测量方法。首先,针对高速旋转体的小量测量,基于立体视觉测量原理设计构建了以无人机为低空移动平台的旋翼轴心轨迹视觉测量系统。其次,针对动-动测量环境条件,提出了地面标定与空中动态实时标定联合的测量系统标定方法。然后,基于空间几何关系,论述了旋翼轴心静态估计与动态轨迹测量方法;最后,进行了测量系统地面精度验证试验与直升机地面开车状态的旋翼轴心轨迹测量试验。试验结果表明,该方法准确可靠,点间距离精度优于1‰,可实现轴心轨迹的非接触精确测量,还可推广应用于其他动态小量测量任务。

用于边境巡逻的定点式多旋翼无人机无线充电系统设计

为了解决目前边境巡逻多旋翼无人机续航能力不足、巡航范围受限的问题,研究了一种应用于沿边境巡逻,具有辅助对准功能的无人机无线充电方案,为无人机执行远距离边境巡逻任务提供保障。设计了中继电能补给站供电和辅助降偏矫正系统,无人机降落后自动对准,开启供电系统实施充电;设计了无人机机载电能接收及充电系统,对发射电能实施有效接收,并转换为可控的恒流及恒压能量流输送至机载电池;搭建了微缩化实验样机,测试结果表明辅助对准系统可实现无人机精确对准,无线充电系统实现了71.3 W能量传输,对应整机充电效率84.6%,机载的电能接收机构仅重28 g。

无人机17kW电机振动噪声分析与巡航转速下尖端噪声优化

随着无人机的迅速发展,噪声问题影响消费者体验及AI交互、语音识别等技术,限制了无人机应用潜力。该文针对一台17 kW无人机用外转子永磁同步电机进行研究。为降低电机尖端振动噪声,且保留原电机电磁性能,重点提出优化磁极和定子开槽的方法。具体以平均转矩、转矩脉动等作为约束条件,构建多目标优化数学模型,并利用混合粒子群优化算法求解。该文深入探讨磁极参数、定子开槽对低阶次径向气隙磁通密度空间谐波特征的影响。并对电机转子模态仿真,以研究径向电磁力与空间模态的作用机理。在多转速情况下,以巡航转速为重点,分析整体电机电磁振动噪声特征。最后,仿真和实验结果表明,电机在巡航转速下的尖端噪声显著减小。验证了优化结构对无人机电机尖端振动噪声有明显抑制作用,对解决无人机噪声问题具有重要意义。

基于改进遗传算法的倾转旋翼无人机区域覆盖路径规划

基于改进遗传算法研究倾转旋翼无人机(TRUAV)在多障碍物约束下的区域覆盖路径规划问题.运用最小跨度算法和往返路径生成算法进行任务区域内的覆盖路径初规划,将区域覆盖问题转化为旅行商问题以优化覆盖路径顺序.为了避开区域内的障碍物,提出鱼尾形避障策略.引入最近邻算法,生成比传统遗传算法质量更高的初始种群,设计三点式交叉算子和动态区间变异算子进行遗传操作以提高所提算法的全局搜索能力,避免算法陷入局部最优.在含多个障碍物的多边形区域算例内仿真验证所提算法的性能.结果表明,相比于逐行路径覆盖算法和传统遗传算法,所提算法的覆盖路径长度减少了7.80%,TRUAV的任务区域覆盖效率显著提升.

纵列双桨无人机的气动仿真分析

为解决纵列双桨无人机的桨叶重叠部分的气动干扰导致的旋翼效率减少问题,基于计算流体力学(CFD)方法对纵列双桨无人机的气动特性进行了仿真分析,包括不同攻角、两桨叶相对位置变化以及整流罩气动外型优化。结果表明:在不同攻角下,无人机的攻角对升力系数的影响大于阻力系数;无人机两桨叶在纵向距离3420 mm、轴向距离540 mm时旋翼的干扰最小,效率最高。之后进行了无人机整流罩优化,得到了更加理想的气动外型。为纵列双桨无人机的气动设计提供了重要的参考和指导,同时也为无人机的发展和应用提供了有益的实践经验。

系留多旋翼无人机通信系统天线布局及仿真分析

设计了一种适用于系留多旋翼无人机通信系统的天线布局,采用FEKO仿真软件进行了电磁兼容仿真分析,并进行了实装试飞。仿真及实测表明,该天线布局方式可适用于多旋翼无人机通信系统。

共轴双旋翼无人机升力测试实验与分析

根据共轴双旋翼无人机结构特点及动力性能分析结果,设计了可调整力臂的杠杆平台,通过杠杆原理将不同大小的力施加到力传感器上,并用数据采集卡采集对应电压,使用MATLAB曲线拟合工具箱拟合出升力与电压间的曲线关系,对力传感器进行标定,从而可以测出共轴双旋翼无人机升力。测试结果表明:电压与升力之间拟合效果良好,可以测量出无人机的升力;该方法对于研究共轴双旋翼无人机升力测试具有一定参考价值。

一种可倾斜六旋翼无人机容错控制方法

常规六旋翼无人机在单个旋翼完全失效后,存在姿态与高度不完全可控的情况,此时采取降级控制策略会使无人机失去静态悬停能力.针对此问题,本文提出了一种可倾斜旋翼的容错控制方法,在经典旋翼结构布局的基础之上,将其中一个旋翼设计成可倾斜结构,通过倾斜角度的改变与控制分配重构,无人机在任意单个旋翼完全失效后均能保持力与力矩的平衡.利用线性规划方法得到无人机的可达力矩集,同时对电机饱和度进行分析,确定了不同旋翼失效后的最优倾斜角.搭建飞行测试平台进行对比验证,实验结果表明,本文提出的方法具有良好的容错效果与鲁棒性,能够保证六旋翼无人机在故障后的稳定飞行与平稳降落.

微小无人机旋翼动力系统性能测试实验教学平台开发

为了满足高等院校交通运输类专业无人机系统教学需求,设计并开发了微小无人机旋翼动力系统性能测试实验教学平台,主要由主体台架系统、控制和数据采集系统、数据显示和分析系统组成。依托该实验教学平台,进行了悬停和前飞状态的旋翼性能测试实验。实验结果表明:配合风洞系统,利用该实验教学平台能够实时获取旋翼动力系统主要性能参数;气动拉力和扭矩直接测量误差均低于0.5%,电流电压直接测量误差为0.2%,桨力效和系统力效间接测量误差均低于5%。该实验教学平台可应用于小型无人机旋翼动力系统性能分析的实验教学。

四旋翼巡检无人机固定时间滑模姿态控制

为了提高突发状况下电力巡检四旋翼无人机快速姿态机动性能,基于积分滑模、齐次理论及固定时间稳定理论,提出了一种四旋翼无人机的固定时间滑模姿态控制方法。首先,基于积分滑模与齐次理论,设计了可固定时间收敛且非奇异的滑模面。随后,提出了保证滑模面固定时间收敛的控制器。基于李雅普诺夫稳定性理论与齐次理论,证明了所提闭环系统的固定时间稳定性。相比传统有限时间滑模控制方法,所提出的固定时间滑模控制方法可以保证控制误差的收敛时间受限于固定常数,因此无论在小角度与大角度机动情况下,所提的方法都能够保证控制误差的快速收敛。其次,基于积分滑模的设计,所提出的固定时间滑模控制方法解决了传统终端滑模的奇异问题。最后,通过仿真对比,验证了所提方法的优势。

多通道双荷载六旋翼无人机动力输出优化控制

六旋翼无人机(unmanned aerial vehicle,UAV)动力系统受到电池功能以及应用环境动态变化等因素的影响,导致动力输出的稳定性不好,为了克服这一问题,提出基于多通道双荷载动态输出调整的六旋翼无人机动力系统设计和控制方法。首先分析六旋翼无人机动力输入参数,以无人机电机电磁转矩、电机转速参数、输出功率损耗和效率等为优化变量,采用多线程动态相匹配和兼容性调制方法,建立无人机动力输出的多通道双荷载动态匹配和任务调度模型,并根据无人机组的任务覆盖半径实现动力的自适应寻优控制,降低额外输出开销,提高无人机生存时间周期。测试结果表明,所设计的无人机动力系统提高了搭载能力,能耗开销较小,动力输出的均衡性较好,提高了无人机的动力输出稳定性和飞行寿命。

多旋翼无人机在特种设备检验中的应用探讨

本文简述了多旋翼无人机系统的组成及基本原理,总结了无人机在大型特种设备检验检测领域中的应用现状,指出了无人机应用于特种设备检验检测所需的缺陷智能识别、路径自动规划和环境感知与自主避障三大关键技术,为无人机在特种设备检验检测领域应用提供研究方向。

Performance characterization on downwash flow and spray drift of multirotor unmanned agricultural aircraft system based on CFD

In recent years,multi-rotor Unmanned Aerial Vehicles(UAVs)have been employed in the field of plant protection in China.Spray drift has been considered a major impact in agriculture aerial spraying,and spray quality in the application of plant protection products.The downwash including wake vortices and downward wind field plays a major role in the dispersal and deposition of pesticide spray released by nozzle(s)equipped in aircraft.Differ from the fixed-wing UAV,the downwash flow of multi-rotor UAV was result from the rotation of rotor.Therefore,a study on off-target drift and ground deposit concerning the rotor rotation was simulated through a series of Computational Fluid Dynamics(CFD)simulations to obtain the influence of downwash.The discrete Phase Model(DPM)was taken to simulate the motion of droplet particles since it is an appropriate way to simulate discrete phases in flow field and can track particle trajectory.In this study,the parameters of CFD simulations were acquired by three kinds of actual replicated experiment.The simulation analysis mainly obtains the droplet drift and deposition rule,the influence of eddy current,and downwash flow caused by the rotor rotation.The results showed that the downwash distribution below different rotors was different owing to the flight angle of inclination,“behind”is the greatest,“middle”is secondly,and“forward”is smallest in value(behind,middle,and forward represent three regions below rotors along flight direction).According to the simulation results,two methods of reducing droplet drift were put forward and specific simulations were carried out to prove their feasibility.The results of this study can provide theoretical support for improving the spray quality of UAV and reducing the drift of droplets.

旋翼式无人机授粉作业冠层风场分布规律

为提高杂交水稻机械化种植效率,扩大父母本种植行宽比,采用旋翼式无人机进行辅助授粉作业。旋翼风场是由无人机旋翼旋转推动空气进行流动作用在作物冠层而形成。风场的覆盖宽度、风场内各方向风速的大小以及风场的分布规律将会直接影响到农用无人机田间作业的效果。该文结合无人机的飞行参数使用风速参数采集系统获取18旋翼无人机的授粉作业风速,其中对于矩阵数据（100×60）的行数据和列数据的意义进行了充分的讨论,总结了行、列数据的特点并结合试验实际情况对数据进行处理。发现3向风速数据的时序变化规律保持有一致性,X向风速在最大值时刻之前其平均值要大于Y向与Z向风速;X向、Y向风速值时序曲线之间的形状特征差异小于X向与Z向或者Y向与Z向之间的形状特征差异。而从3向风速值的空间变化分布情况也可看出无人机飞行轨迹与传感器行阵列交汇点处（9#-11#）所采集风速平均值最大,考虑到测量误差值,随着采样点距离飞行轨迹越远,采样点对应风速值衰减越多。综合二维风场数据可知3向风场宽度对比结果为Y向〉X向〉Z向。在此基础上,采用高斯法拟合等方式对行数据及列数据进行计算,通过对比各统计项的参数,拟合列数据建立风速数据与时间关系的5阶指数函数模型;拟合行数据作为风速数据与采样点分布距离关系的6阶指数函数模型。利用矩阵变换基于行、列数据模型最终建立水稻冠层处无人机旋翼X向二维风场理想模型,且由模型图中可发现无人机沿冠层飞行时旋翼X向风场的分布形状存在＂陡壁＂效应,即无人机旋翼下风速达到最大值,前向风速增大率要明显高于后向减小率,整个风场＂陡壁＂沿无人机飞行方向左右对称。研究将为无人机辅助授粉通过改变风场实现新的作业方法提供参考。