基于等效动稳定性系数的潜艇运动控制方法

对由线性运动方程和Routh-Hurwitz判别法导得的操舵比例函数求解,获得潜艇运动控制新方法,将控制增稳所需的修正舵角与原舵角组合成新指令舵角,可改善潜艇的航行品质。以具有十字舵的某型潜艇为对象求解6自由度运动方程,其中典型的潜艇水下定深回转工况仿真模拟表明:操舵比例系数与水动力导数和等效动稳定系数有关,控制增稳效果受到运动特征量和潜艇操舵角度等因素的影响。潜艇运动控制新方法改善了潜艇航行过程中的运动响应,提高了那些由于自动稳定性不足而难以操控的潜艇的控制稳定性。潜艇运动控制新方法为未来潜艇通过减小操纵面来优化自身综合水动力性能提供了新的技术途径。

Global stability coefficient of large underground caverns under static loading and earthquake wave condition

Underground energy and resource development,deep underground energy storage and other projects involve the global stability of multiple interconnected cavern groups under internal and external dynamic disturbances.An evaluation method of the global stability coefficient of underground caverns based on static overload and dynamic overload was proposed.Firstly,the global failure criterion for caverns was defined based on its band connection of plastic-strain between multi-caverns.Then,overloading calculation of the boundary geostress and seismic intensity on the caverns model was carried out,and the critical unstable state of multi-caverns can be identified,if the plastic-strain band appeared between caverns during these overloading processes.Thus,the global stability coefficient for the multi-caverns under static loading and earthquake was obtained based on the corresponding overloading coefficient.Practical analysis for the Yingliangbao(YLB)hydraulic caverns indicated that this method can not only effectively obtain the global stability coefficient of caverns under static and dynamic earthquake conditions,but also identify the caverns’high-risk zone of local instability through localized plastic strain of surrounding rock.This study can provide some reference for the layout design and seismic optimization of underground cavern group.

Hydrodynamic characteristics of the double-winged otter board in the deep waters of the Mauritanian Sea

In this paper, we tested the hydrodynamic characteristics of a new, double-winged otter board that consists of a forewing, a leading edge slat and a trailing edge flap. Flume experiments were conducted in a circulating flume tank by using a model with an aspect ratio(AR) of 0.85 and a horizontal planform area( S) of 0.09 m^2. The results indicated that the critical angle( α_(cr)) of the model was 44°, whereas the maximum lift coefficient( C_(Lmax)) was up to 1.715, and the door efficiency( K) was 1.122. The attack angle( α) ranged from 30° to 48° and from 10° to 46° when the lift coefficient( C_L) and door efficiency( K) were greater than 1.2 and 1.0, respectively. To compare the difference between double-winged otter board and traditional Morgere Polyvalent Ovale, same model of Morgere Polyvalent Ovale was also tested under the same experimental conditions. The critical angle( α_(cr)) and maximum of lift coefficient( C_(Lmax)) of the doublewinged otter board were 37.5% and 14.6% larger than those of the Morgere Polyvalent Ovale. Therefore, we concluded that the novel, double-winged otter board was more suitable for bottom trawling fisheries in the deep water of the Mauretania Sea due to its better hydrodynamic characteristics and stability.

Implementation of the Concept of Buildings Stability Monitoring in the Project STATIMON： Theoretical and Practical Results

In the framework of the STATIMON project, the complex research was done in which mathematical models of buildings＇ construction were created, defects identification method developed and also monitoring concept was composed according which automated monitoring system and software prototypes and structures were implemented. The strategic aim of the development of buildings＇ monitoring system was realized by mathematical and physical modelling of the faults （defects）; analysis of characteristics sensitive to defects; selection of stability parameters and measurements; creation of automated system prototype; investigation of the methods applied for the monitoring system and diagnostics; development of software and separate elements of the system and approbation of the whole complex. Thorough evaluation of the technical state of the buildings numerical is executed using physical models and natural objects which support reliable state identification of the building and also helps to track changes.

NONLINEAR BOUNDARY STABILIZATION OF WAVE EQUATIONS WITH VARIABLE COEFFICIENTS

The wave equation with variable coefficients with a nonlinear dissipative boundary feedbackis studied. By the Riemannian geometry method and the multiplier technique, it is shown thatthe closed loop system decays exponentially or asymptotically, and hence the relation betweenthe decay rate of the system energy and the nonlinearity behavior of the feedback function isestablished.

The Exponential Stabilization of Uncertain Chained Form Systems of Mobile Robots Based on Visual Servoing

A system for a type of nonholonomic wheeled mobile robots equipped with an uncalibrated camera fixed to the ceiling is investigated.Based on the visual feedback and the state-input transformation,models of uncertain chained form systems are presented for the robot-camera systems.Then,new smooth time-varying feedback controllers are proposed to exponentially stabilize the uncertain chained system by using state-scaling and control theories for two cases.The exponential stabilities of the closed-loop uncertain systems are rigorously proved.Simulation results demonstrate the effectiveness of the proposed strategies.