【作者】 王帆；

【导师】 金鸿章；

【作者基本信息】 哈尔滨工程大学 ， 控制理论与控制工程， 2010， 博士

【摘要】 受风、浪、流等自然环境干扰影响,海上航行的船舶不可避免地会产生六自由度摇荡运动,即横摇、纵摇、艏摇、横荡、纵荡、垂荡,其中尤以横摇最为显著。剧烈的横摇运动严重影响船舶适航性、设备安全性及船员舒适度,因此,提高横摇稳定性至关重要。减摇鳍是迄今应用最广泛且成功的主动式减摇装置,减摇效果可达90%以上,然而因生力机理制约,其零航速下性能极差。尽管减摇水舱具备全航速减摇能力,但体积大、占(船内)空间等缺点使之并非理想选择。论文首先根据牛顿定律、海浪理论分析船舶三自由度非线性耦合模型及广义海浪干扰模型,建立水平面3-DOF运动仿真平台,简述横摇稳定原理与普通减摇鳍缺陷,围绕兼容性、模式切换、造价成本等问题,对单/双翼零航速减摇鳍进行详细讨论,评价各自优缺品质。从自然界水生或半水生动物附体的生力机制研究入手,探讨零航速减摇鳍仿生机理与工作模式。剖析动态水动力成分,针对原模型及建模方法存在的诸多弊端,运用高等流体力学理论,采用数值、解析结合法,建立水动力/力矩、驱动力矩/功率模型,力求足够准确且不失工程实用性。利用CFD软件FLUENT计算流体作用力,分析流场压力与速度分布规律,以FLUENT数据为基准,评定建模精度并讨论误差主要因素。采用权威机构公布的试验方法,测试零航速减摇鳍负载特性,二者结论基本一致。以往研究对鳍型尺寸选择较为随意,缺乏理论依据,且未考虑小展弦比鳍型对常规模式(升力特性)造成的不利影响。论文通过分析减摇鳍流体动力性能,依照常规/零航速模式对鳍型参数的具体要求,应用线性系统理论,提出零航速减摇鳍尺寸参数估算与综合评价方法,获得最佳展弦比范围(不可收放式鳍)。根据仿生机理、水动力建模等结论,兼顾双模式彼此协调,制定前/后缘鳍型优化原则,以课题组在仿生鳍领域的相关成果为基础,从定性或定量角度论证国内外若干仿生变形设计方案。详细阐述零航速减摇鳍系统特征及非线性输入特性,包括记忆性、单调性、饱和约束等,分析被控系统结构形式、对抗式PID设计思想/适用前提,说明其与整体设计法的本质缺陷。应用随机信号分析、谱估计理论建立横摇扰动力矩成形滤波器与增广状态空间模型。依据动态非线性子系统串联动态线性子系统的特殊结构,借助非线性分离策略,提出基于变约束模型预测控制与数值迭代反演的两步主从控制律,运用无源性理论证明该设计的收敛性。仿真结果表明,控制器性能良好,但受物理性硬约束影响,零航速减摇效率随海情增加而呈非线性递减。零航速减摇鳍仍将充当普通减摇鳍而频繁用于中/高航速状态,但此类问题未被重视。论文针对零航速小展弦比鳍型引起的非线性升力特性,研究适用于常规减摇模式的鲁棒自适应神经元控制律,分析其Lyapunov稳定性。仿真结果显示,该设计不仅自适应性较强,而且在各种海情下均可获得满意效果。建立航行阻力模型(指标)对姿控系统综合评定,数据表明,横摇控制有利于降低航行阻力,节省推进能量。更多还原

【Abstract】 The unavoidable motion in six degrees of freedom of ships in underway can be induced by the action of environmental disturbances such as winds, waves and currents. Among all motions disturbed including the rolling-pitching-yawing-swaying-surging-heaving, the roll motion is the most serious so as to influence the ship navigability, security of equipments and comfort of the crew, therefore it is of crucial importance to improve the roll stabilization. Common active fin stabilizers have been considered as the most widely used and effective anti-roll equipments with ninety percent of roll reduction, however they have the poor performance at anchored due to their force generation mechanism. Although anti-roll tanks have the capacity of damping the rolling under any speed, they are not perfect options with several drawbacks such as large volumes and much space occupied in the cabin.As a first step nonlinear models coupled describing the ship motion in three degrees of freedom and generalized wave disturbance models are analyzed according to the Newton law and wave theory, then a platform simulating horizontal motions in three degrees of freedom is established. The principle of roll stabilization and drawbacks existing in common fin stabilizers are presented, and zero speed fins with single and double wings are discussed in detail around problems such as the compatibility, mode switch, cost etc. Their advantage and disadvantage are evaluated impersonally.After a detailed investigation on the force generation mechanism employed by appendages of aquatic and semi-aquatic animals in the nature, the bionic mechanism and working mode for zero speed fin stabilizers are proposed. With analysis of hydrodynamic components and defects from existing models and their modeling methods, models describing hydrodynamics and driving are established with the use of advanced hydrodynamics theory and a composite method of the analytical approach and numerical simulations for the purpose of enough accuracy without loss of engineering practicability. The fluid dynamics is simulated with the computational fluid dynamics (CFD) software FLUENT, then the pressure and velocity distribution is analyzed. The modeling precision is evaluated in comparison with the data from FLUENT and main reasons inducing errors are discussed. The experiment published by the academic authority to test the load characteristic for zero speed fin stabilizers is performed, and their results show good agreement with each other.In previous researches the selection of fin sizes is more optional due to the lack of theoretical basis, and the adverse influence of the low aspect ratio on the conventional working mode such as lift characteristic has been not taken into consideration. With analysis of the hydrodynamic performance, a method on fin size estimation and integrated evaluation for zero speed fin stabilizers is proposed using the linear systems theory according to the detail requirements for the common and the zero speed modes, and then the optimal range of aspect ratio for non-retractable fins is obtained. Based on conclusions of bionic mechanism and hydrodynamic modeling, the principle for optimizing the leading and trailing edges is established to make a compromise between the two working modes. From the viewpoint of quality or quantity, several morphing design proposal both here and abroad are demonstrated on the basis of research findings in the bionics field obtained by the team.The characteristics of the zero speed fin stabilizer system and nonlinear input are explained in detail including the memory, monotonicity and saturation constraints. The structural configuration of the controlled system and design philosophy as well as applicable premise of the opposed PID controller are analyzed, and the essential drawbacks of opposed PID and integrated design is shown. Then the shape filters for roll disturbance moments and augmented state space model are established using the random signal analysis and the spectrum estimation theories. According to the special structure (i.e. dynamic nonlinear subsystem in series with dynamic linear subsystem), a two-step master slave control law consisting of a variable constrained model predictive controller and a numerical iterative inverse controller is proposed by means of the nonlinear removal strategy, and its convergence is proved with the use of the passivity theory. The results from simulations are given to show the good performance of the controller designed, but due to hard constraints induced by physical reasons the anti-roll efficiency under zero speed presents the nonlinear degression with increased sea conditions.As a matter of fact that zero speed fin stabilizers are also used as common fins to reduce the roll motion at the moderate or the high sailing speed, however this problem has been not paid any attention to. For solution of the nonlinear lift characteristic induced by the low aspect ratio, a robust adaptive neuron control law adequate for the conventional anti-roll mode is developed, and its Lyapunov stability is proved. The results from simulations performed show that this design with the better adaptability can obtain the satisfying effect for roll stabilization under any sea conditions. The whole attitude control system is evaluated using the sailing resistance model established, and the fact is testified that damping the rolling is of great advantage to reduce the sailing resistance and save the energy for ship propulsion.更多还原