Dynamic control of a remotely operated vehicle using a neural network

The control of a remotely-operated underwater vehicle to maintain a prescribed depth in shallow water under irregular surface waves is realized through the application of the Robust Adaptive Neuro Controller, a composite control system incorporating—together with the conventional control algorithm—a neural network controller. This network bestows a learning capability on the system, allowing it to deal with unanticipated disturbances that would otherwise cause erroneous behavior of the vehicle. The effectiveness of this application is verified through mathematical simulation of a model vehicle's behavior, through experiment in a model basin, and through simulation of the behavior of an actual remotely operated vehicle in shallow water under irregular surface waves. Graphic data representing the learning process undergone by the neural network distinctly indicate the rising output from the network with the progression of learning, and the vehicle's depth variation traced in terms of the mean square error vividly show the diminution of deviation from the prescribed depth obtained with application of the neural network. Thus controlled to maintain constant depth, under-water vehicles with power supplied externally through a tether for propulsion and for heavy-duty operations should consolidate their advantage for such activities as maintenance of submarine structures and surveys in deep or hazardous water.     

市区软土地层地下工程施工新技术

为了使现代城市更有效率,具有更多功能,全球各大城市愈发关注地下空间的利用问题。然而,由于在大城市很多地下建筑物(如重要市政管线)已经开发,要开发新的地下空间,就要求更好更有效地利用浅层和深层的地下空间。因此,在尽量不影响地下水自然环境及邻近的地下或地上建筑物的前提下,开发适用于深埋和/或大断面建筑物的施工技术显得尤为重要。此外,由于多数亚洲国家大城市的地层由软弱沉积物构成,如黏土、淤泥、砂、砾石层等,且地下水位高;所以,有关现场勘察、设计、安全管理和环境保护监控、地下水处理、土体改良等的新技术都是必需的。根据这些需求,总结了在日本开发的新技术,包括现场勘察与监控技术、隧道及地下工程施工技术、土体改良技术、地下水处理技术与地下径流保持技术等。希望这些技术能够满足各大城市经济高效、环保地开发地下空间的需求。这些新技术不仅对发达国家大城市的地下空开发有用,而且对发展中城市的地下空间开发同样有用。     

Study on the design of propeller blade sections using the optimization algorithm

A new method for designing propeller blade sections is presented. A vortex lattice method is used to evaluate the performance and the time-dependent pressure distribution on the blade surface in a non-uniform flow, while efficient optimization algorithms are used to modify the blade sections. Two different designs were carried out in this study. The first was a design to realize a target pressure distribution in a rotating three-dimensional flow. A two-dimensional wing theory was used to obtain the target pressure distribution. The predicted increase in efficiency and the reduction in the cavity volume were confirmed by model experiments. The second was a design to maximize the propeller efficiency. By this method, the propeller efficiency was improved by 1.2% under the constrains of constant thrust and a prescribed margin for face cavitation.     

超大断面盾构隧道管片施工荷载现场监测研究

盾构隧道施工荷载对隧道结构有不容忽视的影响.文章以上海长江隧道为依托工程,进行了施工荷载的现场监测研究.国内首次在管片外弧面荷载测最中采用日本研发的具有较大受力面的柔性土压力计,实施实时监测,获得了第一手实测数据.数据分析表明,在外弧面上主要受到来自各种荷载当中,盾尾注浆引起的附加荷载最大;将荷载分布与惯用设计法所得设计值相比较发现,施工荷载的最大值大于或接近设计水土压力,但其分布比设计值均匀.