Robust leader-follower formation tracking control of multiple underactuated surface vessels     

彭周华  王丹  兰维瑶  孙刚 《中国海洋工程》2012,26(3):521-534

This paper is concerned with the formation control problem of multiple underactuated surface vessels moving in a leader-follower formation.The formation is achieved by the follower to track a virtual target defined relative to the leader.A robust adaptive target tracking law is proposed by using neural network and backstepping techniques.The advantage of the proposed control scheme is that the uncertain nonlinear dynamics caused by Coriolis/centripetal forces,nonlinear damping,unmodeled hydrodynamics and disturbances from the environment can be compensated by on line learning.Based on Lyapunov analysis,the proposed controller guarantees the tracking errors converge to a small neighborhood of the origin.Simulation results demonstrate the effectiveness of the control strategy.  相似文献   

西安地铁隧道穿越饱和软黄土地段的地表沉降监测   总被引：1，自引：0，他引：1  

贺农农  李攀  邵生俊  李佳坤  焦阳阳 《地球科学与环境学报》2012,(1):96-103

以西安地铁一号线朝阳门站—康复路站区段饱和软黄土地铁隧道为研究对象,通过施工期现场地表沉降变形监测,分析了在饱和软黄土特殊地层条件下隧道浅埋暗挖法施工引起的该区段地表沉降变形规律以及地表沉降槽分布特征。结果表明:在饱和软黄土隧道开挖时,随着掌子面的推进,隧道顶地表沉降可分为沉降微小阶段、沉降显著发展阶段、沉降缓慢阶段和沉降稳定阶段;单线隧道开挖后的最大地表沉降量为18.89mm,双线隧道开挖后的最大地表沉降量为36.4mm;已开挖隧道对围岩土体的扰动作用使得后开挖隧道的地表沉降发展较大;双线隧道的地表沉降槽宽度接近单线隧道沉降槽宽度的2倍,因此可以将其近似为单线隧道地表沉降槽宽度与双线隧道轴线中点距离之和;单线隧道开挖后地表沉降槽宽度为8.4～9.3m,双线隧道开挖后地表沉降槽宽度为16.2～17.5m;隧道开挖施工的沉降槽宽度参数为0.435～0.467,单线隧道开挖后的地层损失率为0.765%～1.324%,双线隧道开挖后的地层损失率为1.231%～2.200%。  相似文献   

Comprehensive Marine Observing Experiment Based on High-Altitude Large Unmanned Aerial Vehicle(South China Sea Experiment2020 of the “Petrel Project”)     

Xuefen ZHANG  Liangxu LI  Rongkang YANG  Ran GUO  Xia SUN  Jianping LUO  Hongbin CHEN  Daxin LIU  Kebing TANG  Wenwu PENG  Xiaodong HAN  Qiyun GUO  Xiaoxia LI  Xikun FEI 《大气科学进展》2021,38(4):531-537

In collaboration with 12 other institutions, the Meteorological Observation Center of the China Meteorological Administration undertook a comprehensive marine observation experiment in the South China Sea using the Yilong-10 high-altitude large unmanned aerial vehicle(UAV). The Yilong-10 UAV carried a self-developed dropsonde system and a millimeter-wave cloud radar system. In addition, a solar-powered unmanned surface vessel and two drifting buoys were used. The experiment was further supported by an intelligent, reciprocating horizontal drifting radiosonde system that was deployed from the Sansha Meteorological Observing Station, with the intent of producing a stereoscopic observation over the South China Sea. Comprehensive three-dimensional observations were collected using the system from 31 July to2 August, 2020. This information was used to investigate the formation and development processes of Typhoon Sinlaku(2020). The data contain measurements of 21 oceanic and meteorological parameters acquired by the five devices, along with video footage from the UAV. The data proved very helpful in determining the actual location and intensity of Typhoon Sinlaku(2020). The experiment demonstrates the feasibility of using a high-altitude, large UAV to fill in the gaps between operational meteorological observations of marine areas and typhoons near China, and marks a milestone for the use of such data for analyzing the structure and impact of a typhoon in the South China Sea. It also demonstrates the potential for establishing operational UAV meteorological observing systems in the future, and the assimilation of such data into numerical weather prediction models.  相似文献   

西安地铁隧道穿越饱和软黄土地段的地表沉降监测     

贺农农  李攀  邵生俊  李佳坤  焦阳阳 《西安地质学院学报》2012,(1):96-103

以西安地铁一号线朝阳门站一康复路站区段饱和软黄土地铁隧道为研究对象,通过施工期现场地表沉降变形监测,分析了在饱和软黄土特殊地层条件下隧道浅埋暗挖法施工引起的该区段地表沉降变形规律以及地表沉降槽分布特征。结果表明：在饱和软黄土隧道开挖时,随着掌子面的推进,隧道顶地表沉降可分为沉降微小阶段、沉降显著发展阶段、沉降缓慢阶段和沉降稳定阶段;单线隧道开挖后的最大地表沉降量为18．89mm,双线隧道开挖后的最大地表沉降量为36．4mm;已开挖隧道对围岩土体的扰动作用使得后开挖隧道的地表沉降发展较大;双线隧道的地表沉降槽宽度接近单线隧道沉降槽宽度的2倍,因此可以将其近似为单线隧道地表沉降槽宽度与双线隧道轴线中点距离之和;单线隧道开挖后地表沉降槽宽度为8．4～9．3m,双线隧道开挖后地表沉降槽宽度为16．2～17．5m;隧道开挖施工的沉降槽宽度参数为0．435～0．467,单线隧道开挖后的地层损失率为0．765％～1．324％,双线隧道开挖后的地层损失率为1．231％～2．200％。  相似文献   

海洋测深中的船移效应研究     

肖付民  刘雁春  夏伟  孙新轩  王美娜 《测绘学院学报》2011,(1)

海洋测深大多是在移动的测量船上进行的,测量船的移动则不可避免地产生船移效应,因而船移效应是影响海洋测深精度的因素之一。在系统推证海洋测深中的船移效应模型基础上,对几种典型船速、水深、海底坡度和波束角情形下的船移效应进行了数值计算,研究了船移效应的影响规律和量级,揭示了船移效应的非对称性影响。根据海洋测深的IHO最低标准要求,提出了采用窄波束和限制船速的降低测深船移效应影响的有效方法。  相似文献   

海底入射角对多波束反向散射强度的影响及其改正   总被引：3，自引：0，他引：3  

金绍华  翟京生  刘雁春  崔高嵩 《武汉大学学报(信息科学版)》2011,36(9):1081-1084

综合考虑测船姿态、声线弯曲和海底地形对入射角的影响,推导了计算多波束海底入射角的实用模型。根据Lambert法则,改正海底入射角对反向散射强度的影响。实例计算结果表明,所述模型能精确地计算波束在海底的入射角,有效地改正其对反向散射强度的影响。  相似文献   

Optimization of fishing vessels using a Multi-Objective Genetic Algorithm     

Mark A. Gammon 《Ocean Engineering》2011,38(10):1054-1064

A fishing boat hull is used as an example of how hull form optimization can be accomplished using a Multi-Objective Genetic Algorithm (MOGA). The particular MOGA developed during this study allows automatic selection of a few Pareto Optimal results for examination by the designers while searching the complete Pareto Front. The optimization uses three performance indices for resistance, seakeeping and stability to modify the hull shape to obtain optimal hull offsets as well as optimal values for the principal parameters of length, beam and draft. The modification of the 148/1-B fishing boat hull, the parent hull form of the ?stanbul Technical University (?TÜ) series of fishing boats, is presented by first fixing the principal parameters and allowing the hull offsets to change, and secondly by simultaneously allowing variation of both the principal parameters and the hull offsets. Improvements in all three objectives were found. For further research the methodology can be modified to allow for the addition of other performance objectives, such as cost or specific mission objectives, as well as the use of enhanced performance prediction solvers. In addition, one or more hulls could be evaluated by experiment to validate the results of using this particular optimization approach.  相似文献   

AIS专题统计分析应用系统研究     

赵忠东  夏启兵 《海洋测绘》2011,31(3):54-57

AIS专题统计分析应用系统以AIS岸基网络系统提供的信息为基础,采用分级、分类、定制等多种技术手段,实现AIS船舶运行信息的有效管理和共享,为航海及其他海洋活动提供更加全面、及时、可靠和集成的综合信息服务,进一步发挥AIS系统信息的社会服务效能.文章描述了系统的实现目标、系统组成、功能模块设计及关键技术,并对系统应用前...  相似文献   

The effects of fin rot disease and sampling method on blood chemistry and hematocrit measurements of winter flounder, Pseudopleuronectes americanus from New Haven Harbor (1987--1990)     

Ziskowski J  Mercaldo-Allen R  Pereira JJ  Kuropat C  Goldberg R 《Marine pollution bulletin》2008,56(4):740-750

Winter flounder from New Haven, Connecticut were evaluated for fin rot disease. Blood samples collected from healthy and diseased fish were used to measure bilirubin, calcium, hematocrit, inorganic phosphorus, osmolality, and total protein. Blood measurements were significantly affected by the presence of fin rot disease and by sampling mode (bled immediately or after 18 h). A reduction in blood chemistry values was associated with fin rot disease. Logistic regression modeling was used to identify explanatory variables contributing to the fin rot outcome in winter flounder. Blood constituent levels were higher in fish bled immediately versus 18 h post-capture, especially among fish without fin rot, suggesting that a waiting period is necessary for blood values to stabilize following initial sampling stress. This study presents evidence that winter flounder blood chemistry and hematocrit measurements are affected by fin rot disease.  相似文献   

High blood lead level among the Mahayana Buddhist monk: a note for environmental implication     

Viroj Wiwanitkit  Jamsai Suwansaksri  Suphan Soogarun 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(6):805-807

Lead has no biological function and is one of the most toxic metals. Of several heavy metals, monitoring of lead is an important focus in occupational medicine. In exposure and risk evaluation, monitoring lead biologically has several advantages over technical exposure assessment. In this article, the authors report a very high blood lead level among the Mahayana Buddhist monks. This is a forgotten high-risk population. The environmental implication in the monitoring and controlling of this population is raised.  相似文献