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。     

棒料高速变节距柔性交接装置设计与优化

针对目前棒料高速柔性交接装置工作可靠性不高,上下游机节距不能根据需要调整,从而限制了下游机速度提高等问题,提出了一种棒料变节距柔性交接装置的工作原理,对棒料交接过程及运动干涉情况进行了分析.为提高棒料柔性交接的可靠性,对装置结构参数进行了多目标优化,改善了棒料轴向制动过程,减小了交接相对速度差和凸轮最大压力角,并通过仿真分析验证了优化设计的合理性.该装置交接定位准确、稳定,轴向制动平缓,变节距技术和装置为设计速度更高的下游机创造了有利条件,具有较高的实用价值.     

基于高速摄像技术的振动落果惯性力研究

【目的】研究果实在激振力作用下脱离枝干的运动规律、果实振动脱落时的加速度和脱落惯性力,为振动式果品收获机的研制提供理论依据。【方法】运用果树振动装置进行了杏果侧枝振动落果试验,采用高速摄像仪对分离过程进行了跟踪拍摄,通过Phantom控制软件对图像进行跟踪、捕捉、分析和计算,探寻杏果实在脱离枝干过程中瞬时速度的变化规律。【结果】杏果实脱离枝干过程中瞬时速度的变化表现为增大-减小-匀速运动-杏果实与枝干完全分离,杏果实与所在枝干的相对瞬时速度最大达到1.723m/s,杏果实的脱落加速度最大为4.270×102 m/s2,脱落惯性力最大为5.124N。【结论】脱落惯性力是杏果实脱离枝干所需的最小作用力,其是确定振动式果品收获机在收获果实的过程中作用于枝干激振力大小的理论依据,也是振动式果品收获机其他性能指标的理论参考。确定适当的激振力,可以保证振动式果品收获机在采收过程中果实的采净率高,同时对果树的损伤最小。     

部分负载测功法的试验研究

汽车维修使用部门测试功率,常使用底盘测功机或无负载加速测功法。前者造价高、后者存在未知转动惯量及测量精度问题,未能普及。该文提出一种部分负载测功法,较好地解决了加速测功法的固有缺陷,又保持了造价低的优点,便于维修部门使用。     

Seismic response of site conditions to Xigeda formation of Xichangthree-dimensional subgrade

In order to find out the effect of site structure and distribution of cut-fill area on the seismic responses rules of Xigeda formation three-dimensional subgrade in Xichang, finite element method software is used to simulate the acceleration distribution on the surface of three-dimensional calculation models under seismic load. This paper discusses differences of subgrade seismic response from three aspects, including platform structure of the site, elevation mutation, and excavation and filling area. And there are four conclusions can be drawn. Firstly, the higher the elevation sites platform is,the greater the acceleration amplification factors are,especially in the changes of vertical acceleration amplification factors. Secondly, a sudden increase of elevation causes a sudden increase of vertical acceleration magnification factors, and acceleration amplification factors is getting smaller while extending to the platform inside. Thirdly, the acceleration amplification factors of filled area are greater than those of the excavation area. Fourthly, because terrain amplification of the seismic response is directional, three-dimensional calculation models should be used to numerical analysis. The results provide an important basis for the Xigeda subgrade base plan selection in Xichang and seismic design.     

基于拟静力法的加筋边坡地震稳定性分析

根据假定的边坡破坏面的几何形状,以拟静力法的理论框架分析了土工合成材料加筋边坡对数螺旋线破坏模式下的地震稳定性,整个计算过程采用极限分析的动力学理论。推导出的表达式能够容易地计算出地震荷载作用下为阻止边坡破坏所必需的加筋力和屈服加速度系数,可方便地用于Newmark滑块法计算地震导致的永久性位移的参数确定和稳定性分析。     

显齿蛇葡萄组培育苗试验

为增加显齿蛇葡萄的繁殖速度,通过组培试验培养显齿蛇葡萄无病毒苗,结果表明:显齿蛇葡萄外植体脱分化以MS+6-BA1.5mg.L-1的浓度的愈伤组织生长最快;在显齿蛇葡萄分化芽的过程中,不同处理组合中以MS+6-BA1.5mg·L-1+NAA0.05mg·L-1表现最好;在显齿蛇葡萄生根培养中,不同处理以1/2N6+6-BA1.5mg·L-1+NAA0.15mg·L-1表现最好。     

结合载荷相关性分析下摆臂快速模拟试验研究

以某轻卡麦弗逊前悬架左下摆臂为分析对象,通过在通县试验场进行摆臂结构及轮心载荷的采集,通过ncode软件对已测载荷谱进行分析提取处理,进而进行六分力载荷与摆臂应变载荷的相关性分析,确定造成摆臂损伤的轮心主导失效载荷,进一步确定摆臂载荷与轮心载荷的回归方程。通过载荷回归前后的损伤对比以及功率谱密度分析,进一步验证了方程的准确性,实现载荷降维。最终,通过摆臂实测载荷实现摆臂加速谱的编制。     

Semi-analytical study on regular sea wave interaction with circular elastic floaters of aquaculture fish cages

In this paper, a semi-analytical model was developed to find the vertical motions and wavefield around elastic circular floaters of aquaculture fish cages in regular waves. The fluid is assumed inviscid, incompressible, and irrotational flow. A regular train of deep water waves was incident to a floater, which consist of two tori of high-density polyethylene (HDPE) pipes. The problem was analyzed with the assumption of the relatively large incident wavelength in comparison to the cross-section of tori. Slender body theory and matched asymptotic expansions were used with the inner solution close to the body section composed of suitable radiation solution at large distance of floater by distributing source and doublet along centerlines of floater constituent tori. In this approach, the fundamental solutions were developed for symmetric and anti-symmetric motions. Then, the governing equations on diffraction and incident waves were decomposed to Fourier modes of these solutions. The main influence parameters on vertical accelerations such as floater dimensions, wave number, the distances between tori, and bending stiffness of floater were studied. The model results demonstrate good agreement with those of the BEM. Furthermore, the Energy Transmission Index (ETI) was introduced for describing the effect of the floater on the downstream environment.     

智能手机实现虚拟角规的原理与设计

分析了利用智能手机摄像头实现虚拟角规测树功能的原理,讨论了实像尺寸偏差和虚拟角规缺口的关系,给出了计算虚拟角规缺口在摄像头中的实像公式,并结合智能手机中的加速度传感器设计了虚拟角规自动改平功能,为开发智能手机在林业行业中的应用进行了有意尝试。