运用多视图几何原理重建鱼类游泳三维轨迹

鱼类行为学数据是水质污染监测的主要依据,也是鱼类自身健康状况的反应,提取鱼类行为学数据对水质监测研究至关重要。为了获取鱼类行为学数据,实验提出了一种运用多视图几何原理研究鱼类轨迹跟踪重建的方法,实验中用3个摄像头分别从正面、侧面、俯视面3个方向监控水箱中鱼的游动,通过前景跟踪法在3个摄像头中分别得到一条二维轨迹,再利用多视图几何融合,计算出鱼类在水箱中游动的三维轨迹,从而可以重建鱼类的游动轨迹。实验重建了单条鱼在水箱中游动的三维轨迹,计算出了鱼类的位置信息和实时速度。研究表明,重建轨迹与鱼的真实轨迹虽然存在0.88~2.88 s的延迟,但结果吻合度较高。     

汽车电子节气门位置最优预见控制

基于线性二次型最优控制理论和线性矩阵不等式处理方法,提出一种适用于汽车电子节气门的位置离散最优预见控制算法,该算法仅通过一组滑动电位计来测量节气门阀片角度位置实现闭环控制。针对节气门的实际使用环境,建立了离散化的节气门状态空间模型,利用状态转移法构建了包含目标信号的扩大误差系统;考虑实际系统中节气门物理参数难以辨识的特点和外部扰动力矩等不确定因素的影响进行了仿真,并基于快速控制原型技术进行了试验验证。仿真和试验结果均表明,所设计的位置最优预见控制算法能够快速准确地跟踪目标开度信号,增强了电子节气门控制系统的稳定性和鲁棒性。     

基于磁通叠加原理的变刚度关节设计与特性研究

基于磁通叠加原理，提出了一种机器人变刚度关节，在减少了关节质量的同时增加了关节刚度的调整速度和运动范围。阐述了通过电信号直接调整永磁-电磁混合式变刚度装置中磁通量，实现刚度改变的工作原理，并以此原理设计关节整体机构。根据磁通连续性原理和虚位移法建立了关节刚度模型，并给出关节刚度随电流和关节位置的变化关系。以变刚度关节刚度模型为基础，设计了变刚度关节位置与刚度协调控制器，搭建了变刚度关节的原理样机。实验结果表明，基于磁通叠加原理的变刚度机器人关节可以实现关节刚度的快速调节，关节的位置和轨迹跟踪精度随着刚度的增加而增加，随着频率的增加而降低。     

迷宫流道内沙粒壁面碰撞模拟与PTV实验

以单个沙粒为对象,研究了沙粒与灌水器流道壁面的碰撞过程.采用计算流体力学CFD数值模拟方法,分析了沙粒与壁面碰撞反弹系数Rc对灌水器抗堵性能的影响.结果表明,反弹系数对灌水器抗堵性能影响较大.利用粒子跟踪测速技术PTV,观测了复杂迷宫流道内沙粒与壁面碰撞过程,测定了不同压力点下矩形流道的碰撞反弹系数,为灌水器数值模拟时反弹系数的设定提供了实验依据,从而可以更加准确评估灌水器抗堵性能.     

IMM-Based Ship-Borne Radar Target Tracking Algorithm

The Kalman filtering algorithm and commonly used maneuvering target tracking models in the target tracking are firstly studied in this paper, tracking performances of all models based on the Kalman filtering algorithm are simulated and analyzed. Then, multiple model target tracking algorithm is analyzed and studied, which uses multiple motion models to match different target motion models and exists interacting between all models. In this paper,the target tracking of shipboard radar is simulated with MATLAB. It shows the feasibility of the interacting multiple model algorithm composed of a CV model and a CA model. The simulation results indicate,this algorithm obtains a better performance in tracking high speed and high maneuvering targets and a better balance between the performance and computational complexity,as well as very practicability, which is suitable for the tracking target of shipboard radar tracking target.     

梳草船导航控制系统设计与试验

摘要：梳草船已逐步成为河蟹养殖池塘水草管理的重要装备，为实现梳草船运行的自动化，设计开发了一款以风机作为驱动装置的梳草船导航控制系统。针对梳草船设计了一套软硬件控制系统，建立了梳草船运动模型并进行了试验验证，采用航向预估PID控制方法和LOS视圆法实现了梳草船的运动控制与路径跟踪，在实际养殖场进行了航速测试，路径跟踪和水草收割试验。结果表明，在所设计的导航系统控制下，梳草船的最大运行速度可达1.14m/s，PID航向控制方法和LOS视圆法可以准确实现梳草船的路径点跟踪，在天气条件良好的情况下，路径跟踪的平均误差小于0.96m，与人工方式相比，单位时间内水草清理重量提高94.3%，有效降低了水草收割的劳动强度，提高蟹塘水草管理自动化水平。     

不同微纳米曝气滴灌入口压力下迷宫流道沿程微气泡行为特征

微纳米曝气滴灌时,微气泡在迷宫流道内的行为特征不明确导致系统的运行缺少科学依据.针对该问题,采用粒子跟踪测速技术(Particle Tracking Velocimetry,PTV),对0.02、0.06、0.10 MPa入口压力下迷宫流道内沿程连续5个位置处的气泡液体进行视频拍摄,分析微气泡在流道内的行为特征和入口压...     

Visual processing of green zones in shared courtyards during renting decisions: An eye-tracking study

We used an eye-tracking technique to investigate the effect of green zones and car ownership on the attractiveness of the courtyards of multistorey apartment buildings. Two interest groups—20 people who owned a car and 20 people who did not a car—observed 36 images of courtyards. Images were digitally modified to manipulate the spatial arrangement of key courtyard elements: green zones, parking lots, and children’s playgrounds. The participants were asked to rate the attractiveness of courtyards during hypothetical renting decisions. Overall, we investigated whether visual exploration and appraisal of courtyards differed between people who owned a car and those who did not.The participants in both interest groups gazed longer at perceptually salient playgrounds and parking lots than at greenery. We also observed that participants gazed significantly longer at the greenery in courtyards rated as most attractive than those rated as least attractive. They gazed significantly longer at parking lots in courtyards rated as least attractive than those rated as most attractive. Using regression analysis, we further investigated the relationship between gaze fixations on courtyard elements and the attractiveness ratings of courtyards. The model confirmed a significant positive relationship between the number and duration of fixations on greenery and the attractiveness estimates of courtyards, while the model showed an opposite relationship for the duration of fixations on parking lots. Interestingly, the positive association between fixations on greenery and the attractiveness of courtyards was significantly stronger for participants who owned cars than for those who did not. These findings confirmed that the more people pay attention to green areas, the more positively they evaluate urban areas. The results also indicate that urban greenery may differentially affect the preferences of interest groups.     

基于PSO的直线电机滑模控制参数优化策略

非线性滑模控制的直线电机伺服系统,由于滑模控制算法涉及的参数较多,会给参数调优带来困难,从而影响控制效果。结合理论分析与仿真方法,以实验采集的样本为基础,通过反向传播神经网络对直线电机伺服系统进行建模;采用非奇异快速终端滑模控制作为控制算法,搭建直线电机运动控制仿真实验平台;利用粒子群算法,在给定范围内优化滑模控制参数;在仿真平台验证所提出参数优化策略的有效性。当指令正弦位移信号为d=40 sin(πt),参数优化前后直线电机的仿真跟随误差的最大值差分别为0.3770,0.1409 mm,且后者的波动范围明显小于前者。     

眼动分析技术在国内景观领域的应用研究进展

为了解眼动分析技术在国内景观领域的应用研究情况，对中国知网（CNKI）数据库收录的相关文献进行分析，并借助CiteSpace软件绘制图谱，梳理眼动分析技术在国内景观领域的应用现状和特点。结果表明：1）2009年眼动分析技术首次应用于国内景观研究中且主要为景观视觉质量分析、道路景观安全性等研究；2）研究作者、研究机构之间缺乏合作与交流；3）在相关论文中硕博论文和核心期刊占比较大，研究主体以高校为主。最后提出展望，未来应广泛探索眼动分析技术在景观研究中应用的可行性。