植保无人机飞控系统与航线规划研究进展分析

应用无人机开展植保作业是有效防治病虫害的重要途径。本文对植保无人机行业发展和相关应用研究进行了综述,分别从植保无人机飞控系统、单机作业航线规划、多机作业调度场景及优化方法 3个角度进行了阐述,以增强植保无人机作业效果与提高作业效率为目标,分析了植保无人机飞行控制系统及航线规划与调度的研究现状。针对植保无人机因作业精度要求高而导致其飞控系统制造成本高的问题,提出应研发低成本、高精度、可适应植保无人机作业需求的测姿器件,开发相应的姿态估计算法;针对植保无人机航线规划、优化调度模型与实际作业需求不匹配的情况,总结了单机作业航线规划与多机调度优化场景、约束条件与优化方法。最后,提出应研发植保无人机自动补给平台,构建基于多机协同的作业管理与调度优化模型,以增强植保无人机在复杂作业环境中的作业效果,提高作业效率。     

电力市场中日有功调度的最大熵技术法寻优

鉴于中国电力工业的发展状况和电力市场过渡时期的特点,利用最大熵技术提出了以总发电容量成本最小和总发电电量成本最小的双目标决策模型。     

Effect of irrigation schedule on growth and seed yield of camelina (Camelina sativa L.) in Tarai region of central Himalaya

Camelina(Camelina sativa)has emerged as a potential biofuel crop globally with its suitability even as a jet fuel source with 75–80%less greenhouse gas emissions compared to common petroleum fuels.The crop has originated from Mediterranean region and belongs to Brassicaceae family.DIBER,DRDO has made initial and pioneer efforts in successful introduction of this crop to India and its agro-technology standardization.Being a short duration crop with lesser input requirement,it fits well in the cropping pattern of hilly states of Indian Himalaya.These areas experience fallow land due to shortage of irrigation water for growing other crops.The present study revealed that irrigation at flowering stage is more beneficial.Irrigation at this stage(if only one irrigation is available)exhibited grain yield of 1.004 kg·m^-2which was 21 and 80%higher over pod setting and rosette stage irrigation,respectively.The maximum seed yield was observed under treatment where irrigation was provided at all three crop growth stages(2.044 kg·m^-2).It was 50%higher over T6 treatment(where two irrigations were given at rosette and flowering stage)and 104%higher over T3(where only one irrigation was given at flowering stage).     

Agronomic and economic response to furrow diking tillage in irrigated and non-irrigated cotton (Gossypium hirsutum L.)

The Southeast U.S. receives an average of 1300 mm annual rainfall, however poor seasonal distribution of rainfall often limits production. Irrigation is used during the growing season to supplement rainfall to sustain profitable crop production. Increased water capture would improve water use efficiency and reduce irrigation requirements. Furrow diking has been proposed as a cost effective management practice that is designed to create a series of storage basins in the furrow between crop rows to catch and retain rainfall and irrigation water. Furrow diking has received much attention in arid and semi-arid regions with mixed results, yet has not been adapted for cotton production in the Southeast U.S. Our objectives were to evaluate the agronomic response and economic feasibility of producing cotton with and without furrow diking in conventional tillage over a range of irrigation rates including no irrigation. Studies were conducted at two research sites each year from 2005 to 2007. Irrigation scheduling was based on Irrigator Pro for Cotton software. The use of furrow diking in these studies periodically reduced water consumption and improved yield and net returns. In 2006 and 2007, when irrigation scheduling was based on soil water status, an average of 76 mm ha⁻¹ of irrigation water was saved by furrow diking, producing similar cotton yield and net returns. Furrow diking improved cotton yield an average of 171 kg ha⁻¹ and net return by $245 ha⁻¹ over multiple irrigation rates, in 1 of 3 years. We conclude that furrow diking has the capability to reduce irrigation requirements and the costs associated with irrigation when rainfall is periodic and drought is not severe.     

The effects of irrigation methods with effluent and irrigation scheduling on water use efficiency and corn yields in an arid region

A great challenge for the agricultural sector is to produce more food from less water, particularly in arid and semi-arid regions which suffer from water scarcity. A study was conducted to evaluate the effect of three irrigation methods, using effluent versus fresh water, on water savings, yields and irrigation water use efficiency (IWUE). The irrigation scheduling was based on soil moisture and rooting depth monitoring. The experimental design was a split plot with three main treatments, namely subsurface drip (SSD), surface drip (SD) and furrow irrigation (FI) and two sub-treatments effluent and fresh water, which were applied with three replications. The experiment was conducted at the Marvdasht city (Southern Iran) wastewater treatment plant during 2005 and 2006. The experimental results indicated that the average water applied in the irrigation treatments with monitoring was much less than that using the conventional irrigation method (using furrows but based on a constant irrigation interval, without moisture monitoring). The maximum water saving was obtained using SSD with 5907 m³ ha⁻¹ water applied, and the minimum water saving was obtained using FI with 6822 m³ ha⁻¹. The predicted irrigation water requirements using the Penman-Monteith equation (considering 85% irrigation efficiency for the FI method) was 10,743 m³ ha⁻¹. The pressure irrigation systems (SSD and SD) led to a greater yield compared to the surface method (FI). The highest yield (12.11 × 10³ kg ha⁻¹) was obtained with SSD and the lowest was obtained with the FI method (9.75 × 10³ kg ha⁻¹). The irrigation methods indicated a highly significant difference in irrigation water use efficiency. The maximum IWUE was obtained with the SSD (2.12 kg m⁻³) and the minimum was obtained with the FI method (1.43 kg m⁻³). Irrigation with effluent led to a greater IWUE compared to fresh water, but the difference was not statistically significant.     

考虑生态径流过程的运行模式对文峪河梯级水库综合效益的影响

生态流量控制与水库其他效益之间的矛盾是河流生态流量保障实践运行的最大障碍,协调生态保障与水库既得利益间的平衡关系是开展面向河流健康的水库调度的重要前提。本研究以河流生态需水过程为生态控制目标,结合文峪河梯级水库的运行需求,划定不同阶段的多目标寻优秩序,并据此建立梯级水库多目标调度模型。依据不同水平年来水状况及远景年的相应措施,设置不同调度情景进行梯级水库模拟调度,得到不同情景下的梯级水库调度方案。最后,对方案中梯级水库的供水保证率、发电量、生态保证率等指标进行统计对比,分析无、低限、适宜三个生态流量控制下的文峪河梯级水库综合效益统计指标的变化规律。研究结果显示：(1) 三个生态流量约束限制,对下游的城镇与工业用水影响不大,其保证率高达99.39%。(2) 对灌溉用水而言,由于将生态流量优先权设置在灌溉用水前,对农田灌溉用水的影响是客观存在的,农田灌溉用水的保证率随生态流量的增加,有所降低,适宜生态流量控制方案较不考虑生态约束方案,保证率下降了10%,且很多枯水年份,破坏的月份达到了8个月,即一年中大部分月份不能满足灌溉需求,可见其破坏程度以及其潜在的经济社会影响不容小视。(3) 三个方案下泄的生态水量都较多,且水量过程差别不大,但生态水量下泄多发生在灌溉用水满足的时段。(4) 由于城镇工业用水、农业用水以及生态用水都是从下游取水,其变化对发电量的影响较小。且实施最小生态控制情况下,梯级水库的强制下泄水量有所减少,为柏叶口和文峪河水库间的补偿调节,提供了更多的空间。通过联合运用,在保障下泄水量要求的情况下,柏叶口相对增发,使梯级总发电量增大,并略高于其他两种方案。     

DPSA和大系统分解协调在梯级水电站短期优化调度中的应用研究

建立了梯级水电站短期优化调度的数学模型,在此基础上探讨了逐次逼近(DPSA)和大系统分解协调2种降“维”算法的主要思想和实现方法,并对其进行了较深入的对比分析,认为2种算法的核心思想是相同的,都将收敛于满意优化解。决策者可根据计算精度和时间等的需要从不同优化方法中选择,以寻求满意解。最后给出了2种优化算法在工程中的算例,其结果可供实际应用参考。     

黄淮海平原典型区冬小麦水分胁迫规律与灌溉策略

黄淮海平原区是中国主要的水分亏缺区,进行合理的灌溉,充分提高水分利用效率是近些年该地区农业研究的重要课题。该文利用环境政策综合气候模型（environmental policy integrated climate,EPIC）,通过模拟黄淮海平原典型区河北沧州地区冬小麦在3种灌溉情景下的生长过程探索合理的灌溉策略。首先通过雨养（无灌溉）情景模拟,分析在当地气候条件下冬小麦生长期内水分胁迫的变化规律,然后通过自动灌溉,调整单次灌溉最大量来分析产量、水分利用效率的变化规律,并根据灌溉实施过程探索合理的人工灌溉方式进行手动灌溉模拟。研究发现：该地区冬小麦在生长期内缺水严重,存在4个主要的水分胁迫期,分别位于分蘖期、返青期、拔节期和灌浆期;通过分析自动灌溉结果,冬小麦在播种期需灌溉10 mm,分蘖期40 mm,返青期35 mm,拔节期35 mm,灌浆期10 mm,能在提高产量的同时保证水分利用效率在一个较高的水平;试验证明,利用EPIC模型可较好地进行作物的水分胁迫与灌溉策略研究。     

基于LPV增益调度的风电机组控制验证与仿真分析

随着风力发电机组装机容量的持续增加,风力发电机组出力特性及其优化运行成为行业关注的热点。针对湍流风下风电机组的动态响应特性,提出抑制风湍流的LPV增益调度控制方法。基于2 MW风电机组模型进行控制器设计,分别采用PI控制算法与LPV控制算法进行仿真计算。机组载荷的波动主要集中在风轮旋转频率1 P的倍频上。仿真计算结果表明在不同风速下,机组显示出不同的运行特性。在低风速时,塔影效应的作用较为显著,在高风速时,湍流对载荷的影响较为明显。相比于PI控制,LPV控制能够跟随机组运行状态调整控制参数,能更好的抑制湍流对机组的影响。在16 m/s湍流风下,功率和齿轮箱低速轴转矩在3P分量上分别降低了35.1%和41.8%。因此,在LPV控制下,齿轮箱的疲劳损伤降低了,发电机的功率波动减缓了。能够增加风电机组的预期寿命,对电网也更加友好。     

基于AquaCrop模型的南疆无膜滴灌棉花灌溉制度优化

为探究AquaCrop模型对南疆地区无膜滴灌棉花种植的适用性、寻求最优灌溉制度,以2018—2019年田间实测数据对模型进行校验,并利用校准模型分别模拟2种不同灌水情景下的棉花冠层覆盖度、生物量及产量的变化规律。结果表明：采用AquaCrop模型模拟2019年冠层覆盖度的均方根误差（RMSE）、拟合指数（d）、标准均方根误差（NRMSE）及决定系数（R2）分别为6.03%、0.12、13.08%和0.97,生物量模拟的各参数分别为810kg/hm2、0.93、6.41%和0.80,产量模拟的各参数分别为751kg/hm2、0.84、14.02%和0.87,说明AquaCrop模型可以较好地模拟南疆地区无膜滴灌棉花的生长与产量。基于1960—2019年的气象数据,利用AquaCrop模型对无膜滴灌棉花进行情景模拟：灌水周期相同时,无膜滴灌棉花产量随灌溉定额的增加呈先增加、后减小的变化趋势,总灌水量为7200m3/hm2时产量达到最大值（5398kg/hm2）,水分利用效率（WUE）为0.75kg/m3;灌溉定额相同时,无膜滴灌棉花产量随灌水周期的增加而增加,总灌水量为5400m3/hm2、灌水周期为5d时,产量达到最大值（5315kg/hm2）、WUE为0.98kg/m3。研究表明,灌水周期5d、灌溉定额540mm的灌溉制度可保证无膜滴灌棉花具有较高的产量和水分利用率,可作为无膜滴灌棉花的参考灌溉制度在南疆地区推广应用。