基于速度选择切换型视线法的无人帆船循迹航行

[目的]风帆的力矩以及海浪作用会造成帆船相比其他形式的动力船舶更容易偏离期望轨迹,这便要求无人帆船的循迹航行算法具有较强的抗干扰能力。[方法]对实船进行等比例建模并通过VPP速度预测程序获得帆船在不同航向下的较大速度,提出一种无人帆船速度选择切换型视线法,在保证无人帆船依靠风力获取速度的同时,再利用切换型视线法使无人帆船的航向角收敛于期望航向角,从而使无人帆船可以快速不断地驶向期望航向点。[结果]Matlab对比仿真研究表明,速度选择型视线法具有偏航误差小、抗干扰能力强且收敛速度较快的优点。[结论]无人帆船在不同风向下的湖上试验验证了速度选择型视线法的可行性,结果具有一定的工程应用价值。

基于模糊PID的无人帆船航向控制方法

[目的]无人帆船在复杂海况下会出现航向状态不稳定的现象,为提高帆船在多变和未知环境下的抗干扰能力与航行的稳定性,实现对帆船航向的准确控制,提出一种结合传统PID技术的模糊自适应控制方法。[方法]建立响应型三自由度的Nomoto运动数学模型,借助Matlab的Simulink建模工具搭建模糊规则和仿真控制器,对PID控制参数进行实时在线优化调整。分别在不同航速和加入随机扰动下,与传统PID控制进行对比研究,分析不同的控制方法对航向的影响情况,并通过试验进行对比验证。[结果]结果表明,应用模糊PID方法控制小型无人帆船的航向,具有较好的自适应能力和较强的鲁棒性。[结论]研究成果可为无人帆船的航向控制设计提供参考。

Quality Control on Crimping of Large Diameter Welding Pipe

Crimping is used in production of large diameter submerged-arc welding pipes. Many researches are focused on crimping in certain manufacturing mode of welding pipe. The application scopes of research achievements become limited due to lack of uniformity in theoretical analysis. In order to propose a crimping prediction method in order to control forming quality, the theory model of crimping based on elastic-plastic mechanics is established. The main technical parameters are determined by theoretical analysis, including length of crimping, base radius of punch, terminal angle of punch, base radius of die, terminal angle of die and horizontal distance between punch and die. In addition, a method used to evaluate the forming quality is presented, which investigates the bending angle after springback, forming force, straight edge length and equivalent radius of curvature. In order to investigate the effects of technical parameters on forming quality, a two-dimensional finite element model is established by finite element software ABAQUS. The finite element model is verified in that its shapes error is less than 5% by comparable experiments, which shows that their geometric precision meets demand. The crimping characteristics is obtained, such as the distribution of stress and strain and the changes of forming force, and the relation curves of technical parameters on forming quality are given by simulation analysis. The sensitivity analysis indicates that the effects of length of crimping, technical parameters of punch on forming quality are significant. In particular, the data from simulation analysis are regressed by response surface method （RSM） to establish prediction model. The feasible technical parameters are obtained from the prediction model. This method presented provides a new thought used to design technical parameters of crimping forming and makes a basis for improving crimping forming quality.

藜麦生长素结合蛋白基因ABP1的鉴定与表达分析

生长素结合蛋白ABP1已被证实具有生长素受体功能。以拟南芥(Arabidopsis thaliana)的ABP1为基础,通过BLAST筛选藜麦的ABP1基因、蛋白质序列,并结合生物信息学方法对其理化性质以及亚细胞定位、二级和三级结构、蛋白序列的motif及domain、系统进化树、启动子顺式作用元件进行了分析。结果显示:藜麦基因组有2个编码ABP1基因CqABP1.7g和CqABP1.17g,位于Chr07和Chr17,等电点为6.03到6.35,蛋白质中脂肪族侧链氨基酸含量的相对值为90.88%到96.22%,且亚细胞定位在细胞质、内质网上;二级结构以延伸链、无规则卷曲和α-螺旋为主。藜麦的ABP1与甜菜的同源关系更近,在进化上出现了单双子叶的分化。CqABP1.17g在藜麦花中高水平表达,而CqABP1.7g在籽粒发育过程高水平表达;在CqABP1.17g中发现多个插入缺失(INDEL)变异,CqABP1.7g中只发现1个INDEl变异,未检测到移码突变;预测的互作蛋白有生长素外排载体、鸟嘌呤核苷酸交换因子SPIKE1、含CRIB结构域的蛋白等。该研究结果为进一步探讨CqABP1s基因功能,调控藜麦生长发育提供一定的理论基础与试验依据。