直线型植保无人机航姿UKF两级估计算法

针对直线型植保无人机航姿测量受磁场干扰严重、磁力计校准动态性能差、航姿估计精度低等问题,提出了一种基于磁力计实时校准的无人机航姿两级解算方法。依据地磁场矢量变化小的特点,利用列文伯格-马夸特（Levenberg-Marquardt,LM）算法和磁力计误差模型,建立磁力计实时校准模型,实时计算磁力计误差参数。考虑运动加速度、电机磁场以及环境磁场干扰,采用无迹卡尔曼滤波器（Unscented Kalman filter,UKF）融合陀螺仪和加速度计实现一级航姿估计,通过四元数精准解析出横滚角和俯仰角姿态信息;然后融合磁力计实时校准数据和陀螺仪修正航向角完成二级航姿估计,最终实现无人机姿态和航向的精准估计。试验结果表明,在外部磁场干扰高达30.97μT时,实时校准算法仍可快速计算出磁力计校准参数,模长均方根误差为0.59μT,减小了航向观测信息噪声。本文的航姿测量系统姿态角均方根误差不大于0.75°,航向角均方根误差为1.40°,较互补滤波算法,姿态角精度提高约0.6%,航向角估计精度提高1.38°;动态飞行试验中,姿态估计算法大幅减弱了磁干扰影响,航姿跟踪准确,航向角快速收敛,稳态精度更高。     

田间作业车辆外部加速度辨识与姿态测量系统研制

复杂田间作业环境与精细作业效果要求农机装备具备实时精准感知农机具姿态的能力,田间作业时普遍存在的车辆外部加速度对此带来挑战。为进一步提高农机装备作业质量,该文以6轴微惯性传感器为硬件传感器,以方向余弦矩阵法进行姿态解算,基于一阶外部加速度模型设计卡尔曼滤波融合算法,实现动态情况下田间作业车辆外部加速度辨识与姿态精准估计。分别采用Innova 2100型摇床与装配有MTi300航向姿态参考模块的高地隙喷雾机对系统进行试验验证。摇床试验结果表明:在外部加速度小于10g情况下,系统对外部加速度辨识误差小于0.214 m/s2;田间作业高地隙喷雾机试验结果表明,相比于MTi300,横滚角最大误差为0.23?,俯仰角最大误差为0.39?。说明该文研制姿态测量系统可准确辨识外部加速度与测量姿态,研究结果可为满足精细农业作业要求的姿态测量系统研发提供依据。     

基于姿态实时监测的多路精准排肥播种控制系统研究

针对现有精准排肥播种控制系统缺少对机具姿态进行监测判别的现状,在现有精准排肥播种控制系统架构基础上,增加了机具作业姿态实时监测模块,使系统可以根据机具的实时前进速度和作业姿态自动控制排肥量和播种量,减少人员对系统的操作。该系统主要由车载控制终端、PID控制器、多路集成比例阀、光电转速测试码盘、机具姿态解析模块、机具位置与速度解析模块、液压马达等组成,其中机具姿态解析模块采用MPU6050芯片实时测量下拉杆与机架的俯仰角,应用STM32F103MCU芯片实时获取MPU6050芯片的输出数据,并反馈到车载控制终端,封装后的机具姿态解析模块安装在拖拉机三点悬挂的下拉杆中部,对下拉杆与水平面的夹角数据进行实时记录和反馈,判别机具的作业姿态是否处于工作状态。将该控制系统安装在小麦基肥精准分层施肥播种机上,在北京市昌平区小汤山国家精准农业研究示范基地,对该控制系统进行静态标定和动态试验,以检测可靠性和稳定性。静态标定试验结果显示,马达转速与系统的排肥排种量存在一元线性关系,此时浅层肥料、深层肥料和种子的单圈排量分别为16.97、29.31、11.2g;姿态标定结果表明,设置临界角为5.3°时,系统的机具姿态提示信息正确,能够满足姿态监测的要求;动态试验表明,机具工作状态下,浅层肥料、深层肥料和种子排量变异系数分别为3.5%、3.8%和3%,3路的排量偏差都控制在5%以内,机具抬升状态下,排肥排种轴处于静止状态,说明该系统的运行过程总体比较稳定,能够满足小麦基肥分层施肥播种机具的精量排肥排种的作业要求,同时能够减少人为操作流程。     

济南市消费者对转基因食品的认知态度的调查与分析

为了了解济南市消费者对转基因食品的认知度和态度，分析影响当地消费者对转基因食品态度的主要因素及对转基因食品发展前景的看法，对当地不同人群随机发放问卷进行了调查。调查结果表明，当地消费者对转基因食品认知度总体较低，大多数消费者对转基因食品采取中立态度。被调查者的心理因素、认知度及其所接触的媒体等与对转基因因食品态度有不同相关性，以媒体相关性最为显著；大多数消费者对转基因食品继续发展持支持态度。媒体极端的负面报道可能会对消费者的态度产生消极影响。当前转基因食品发展相对忽视了消费者的消费需求，但转基因食品发展前景乐观。     

盾构掘进姿态控制技术研究

盾构机在城市地铁施工中已经成为主流,盾构在掘进中的姿态控制是确保隧道施工质量的关键技术.由于影响盾构掘进姿态的因素较多,情况复杂,掘进姿态控制难度大.本文结合南京地铁三号线某标段隧道盾构施工,分析隧道设计轴线、盾构轴线和管片中线三者在施工中存在的5种位置关系：一是三条线基本重合,二是盾构轴线与隧道轴线重合,三是管片中线与隧道设计轴线重合,四是管片中心与盾构轴线有偏差,五是三条轴线不重合而且轴线水平移动;从土压的设定值、地质变化、注浆位置与时间、转弯管片的使用、管片的姿态和施工的连续性等6个方面对影响盾构掘进姿态的因素进行总结;从偏移量、油缸行程差和最小盾尾间隙三个方面对盾构掘进姿态控制的参数进行分析与计算;从掘进方向的控制,掘进姿态调整与纠偏两个方面阐述盾构掘进过程中姿态控制的技术方法.     

城市农民工子女融合困境与建议——基于农民工子女的城市融合与城市居民接纳态度之间的偏差

基于对江苏省苏州市、无锡市、南京市处于义务教育阶段的农民工子女及其家庭、城市居民的问卷调查,从农民工子女的城市就读情况、日常生活的市民化程度和身份认同等层面展开调查分析,重点考察农民工子女的城市融合与城市居民接纳度之间的偏差和不对等问题,分析问题产生的原因,提出相关建议,以期有效促进城市农民工子女的顺利融合。     

Assessment of motivation and attitudes of forest industry companies toward forest certification in northwestern Russia

This study explores for the first time the attitudes and motivation associated with forest certification among forest industry companies in northwestern Russia. Interviews were carried out in the form of a structured questionnaire including 35 forest industry companies operating in northwestern Russia. Although development of certification in individual companies was initiated by general market demand, representatives of certified companies also emphasized the importance of internal corporate policy. Certified and noncertified groups of respondents identified market demand as a main driving force influencing development of forest certification. Ensuring the legality of wood origin, company's image and competitiveness of wood products were recognized as the most important benefits associated with forest certification. Absence of mandatory requirements from authorities and customers appeared to be the largest obstacle among both groups of respondents. Representatives of noncertified companies pointed out economic inaccessibility and low level of preparedness of management as of high importance, which is mainly associated with absence of quality management system. The results of the study indicated a general positive attitude on forest certification; it was noticed that respondents have gaps in understanding the principles and limited awareness with regards to forest certification, especially among noncertified forest industry companies.     

桔小实蝇在云南蒙自地区的发生规律研究

桔小实蝇寄主范围广、繁殖量大、危害重,是世界性的重要检疫害虫。本文通过调查分析,研究了云南蒙自市的海拔、防治措施、果树种类三因素对桔小实蝇种群动态的影响。结果表明,桔小实蝇在1412 m低海拔地区的种群数量大于1608 m和1700 m高海拔地区的,这说明海拔越高,桔小实蝇种群数量越小,危害也越小。根据在相似海拔地区相同果园桔小实蝇种群数量的比较,发现严格按照本课题组探索的防治措施做好桔小实蝇防治能收到良好的效果。蒙自市的水果成熟期不同,随着各种水果的成熟,桔小实蝇种群动态会出现多个峰值,3~5月桔小实蝇种群高峰期主要出现在枇杷园,7~10月主要出现在石榴园、小红枣园和水蜜桃园。对桔小实蝇在蒙自种群动态的调查,能够为下一步防治措施的制定做好准备。     

Assessing the perceived utility of wood resources in a protected area of Western Tanzania

To identify factors associated with interest in gaining access to protected wood resources in western Tanzania, I collected demographic, socio-economic and wood-use data for 240 households in three villages bordering Katavi National Park. Interest in accessing the protected wood resources was not associated with fuelwood needs, and did not fall along ethnic or demographic lines. Instead, logistic regression analysis identified material and land wealth as variables that increase households' interest in accessing wood resources in the Park, whereas intent to move in the near future and the interaction of material and land wealth were negative influences. These results suggest that resource-use interests are largely dependent upon expected individual gains, which vary according to household needs and ability to process resources for potential local sale or trade. This study considers the importance of distinguishing between people's conservation attitudes and their interest(s) in using specific resources, emphasizing the need to recognize intra-community variation in use interests.     

努力提高大学生的科学素质

本探讨了科学素质的构成因素是：科学知识；科学态度；科学方法；科学与技术；科学与社会；科学与人，提出提高大学生科学素质的几个途径。