Synchronized path following control of multiple homogenous underactuated AUVs

This paper addresses the problem of synchronized path following of multiple homogenous underactuated autonomous underwater vehicles(AUVs).The dedicated control laws are categorized into two envelopes:One is steering individual underwater vehicle to track along predefined path,and the other is ensuring tracked paths of multiple vehicles to be synchronized,by means of decentralized speed adaption under the constraints of multi-vehicle communication topology.With these two tasks formulation,geometric path following is built on Lyapunov theory and backstepping techniques,while injecting helmsman behavior into classic individual path following control.Synchronization of path parameters are reached by using a mixture of tools from linear algebra,graph theory and nonlinear control theory.A simple but effective control design on direct inter-vehicle speed adaption with min- imized communication variables,enables the multi-AUV systems to be synchronized and stabilized into an invariant manifold,and all speeds converge to desired assignments as a byproduct.Simulation results illustrate the performance of the synchronized path following control laws proposed.     

关于思想道德修养课教学方法改革的思考

为适应日益发展的新形势需要 ,提高思想道德修养课的实效性和针对性 ,在教法改革方面提出了几点思考 ,对该课程功能的发挥将会起到积极的作用     

不同Al含量的310S耐热钢热轧加工后的组织和力学性能

通过压力机和热轧机对WS-4非自耗真空电弧炉熔炼制备的Al质量分数为0、2％、4％、6％的310S耐热钢进行开坯轧制,用光学金相显微镜观察金相组织,用EPMA-1600电子探针分析组织中各元素分布,结合EPMA能谱分析确定合金中的相组成,并测定室温拉伸性能.结果表明:随着Al含量的增加,钢中碳化物的数量明显减少,且形态逐渐由团聚状向颗粒状转变;部分Al元素以Al4 C3相的形式出现富集,且Al元素含量越高富集现象越严重;合金的屈服强度略有降低,Al质量分数为2％的合金具有最高的抗拉强度及延伸率.各成分合金的综合力学性能明显高于国家标准对热轧310S板材的要求.     

藏药大三果的抗超氧阴离子自由基作用研究

研究藏药大三果对超氧阴离子自由基的清除作用．方法：利用邻苯三酚自氧化体系生产超氧自由基,用单扫描示波极谱法进行检测．结果：大三果牛甘果、毛诃子、诃子的抑制率为50％时的相应浓度（IC50）为,0.163,0.172,1.326mg／mL,结论：发现分析的藏药大三果在一定程度上能清除超氧自由基,且牛甘果的效果最好.