【作者】 张晓飞；

【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， 2009， 博士

【摘要】 船舶在风浪中不可避免地会产生各种摇荡,其中以横摇最为显著,影响也最大。减摇鳍是目前最常用且应用最成功的船舶主动式减横摇装置,减摇效果可达90%以上。但是只有船舶的航速较高时,减摇鳍才可以有效地减摇,在低航速或零航速情况下,减摇鳍几乎不能进行减摇。在现有的减摇设备中,只有减摇水舱的减摇效果不受航速影响,但是减摇水舱体积较大,而且只是在谐摇频率的附近才能取得最好的减摇效果,在某些情况下甚至会出现增摇的现象。为了解决这些问题,人们提出了零航速减摇鳍的概念。论文来源于国家自然科学基金项目“零速下船舶仿生减摇鳍升力机理的研究(50575048)”,主要研究内容是零航速减摇鳍升力模型的建立及其控制方法的研究。论文首先总结了零航速减摇装置的发展现状,明确了研制零航速减摇鳍需要解决的关键技术。分析了减摇鳍在零航速下的工作原理,并且对单翼与双翼零航速减摇鳍的结构与工作方式进行对比。升力模型的建立是研究零航速减摇鳍的基础,论文应用流体力学理论对零航速减摇鳍的升力模型问题进行了初步研究,采用解析的方法对单翼零航速减摇鳍上各种流体作用力的产生机理和影响因素进行分析,建立了单翼零航速减摇鳍的升力模型,并根据升力模型对单翼零航速减摇鳍的升力特性进行分析。仿真结果表明,单翼零航速减摇鳍属于大惯性负载,对伺服系统有较高的要求。在分析Weis-Fogh机构势流理论的基础上建立了双翼零航速减摇鳍的升力和力矩模型,由于现有的理论只能对Weis-Fogh机构张开阶段进行分析,为了解决这个问题,结合数值计算的结果建立了具有较高实用性的Weis-Fogh机构闭合阶段升力模型,并对双翼零航速减摇鳍以不同的速度张开和闭合时的升力和力矩特性进行了研究。针对现有单翼零航速减摇鳍存在的某些缺点,提出了回转运动型单翼零航速减摇鳍的设计方案,仿真结果表明采用该方案可以提高现有零航速减摇鳍的性能。零航速减摇鳍处于非定常流中,只能在理论分析的基础上建立一些初步的升力模型,因此必须根据实验数据对这些模型进行修正。由于零航速减摇鳍周围的流场与传统减摇鳍有很大差别,所以需要对其水动力实验方法进行深入研究。为此对零航速减摇鳍的流场特性进行分析,提出了零航速减摇鳍的水动力实验方案,利用相似理论确定了部分实验参数,为保证实验数据的准确性提供了理论依据。现有的减摇鳍全部采用电液伺服系统,缺点是维护比较困难。为了提高系统的可靠性和可维护性,讨论了电动伺服系统在零航速减摇鳍上的应用,建立了永磁同步电机传动系统的CARIMA模型,在此基础上采用广义预测控制算法对传统电动伺服系统进行改进。为了改善零航速减摇鳍在满负荷状态时的动态性能,在基本广义预测控制中引入了对输入和输出的约束。仿真结果表明,广义预测控制器能够改善伺服系统的动态性能,提高零航速减摇鳍的减摇效果。在有航速减摇时,减摇鳍随船体一起运动,伺服系统只是把鳍转到某一特定角度,鳍上的升力是由船舶航行时鳍和水流的相互作用产生的,它间接利用了船舶主机的能量。在零航速减摇时,对抗横摇所消耗的能量完全由减摇鳍的伺服系统提供,但是伺服系统的功率一般比主机小得多,导致在浪级较高的情况下减摇效果不理想。为了在保证减摇效果的前提下,尽可能减少系统能量消耗,对内环的减摇鳍伺服系统和外环的船舶横摇控制器两个方面进行优化。在伺服系统方面,应用极小值理论对基于能量指标的最优运动规律进行研究,以确定采用何种驱动方式才能提高升力与能量消耗的比值。理论分析的结果表明,采用合适的驱动方式能够以较小的能量产生最大的升力,并且可以避免反向升力带来的不利影响。在船舶横摇控制器方面,根据海浪的频谱特性对系统进行扩展,在此基础上采用随机最优控制理论得到了基于二次型性能指标的最优控制规律。为了找到能量消耗和减摇效果的最佳匹配点,提出了性能指标加权阵的参数自调整准则,并采用遗传算法对不同情况下加权阵的对角线参数进行了优化。结果表明,正确选择加权矩阵参数可以使性能指标取得极小值,实现能量指标最优。更多还原

【Abstract】 Ship swaying motions are inevitable for a storm-tossed ship.Among these motions,roll motion is the most prominent and affecting.Fin stabilizers are the most successful and most widely used active equipments for roll reduction.90 percent of roll motion can be eliminated by using fin stabilizers.Traditional fin stabilizer can reduce roll motion remarkably when the ship is sailing at high speed. If the ship is sailing at low or zero speed,traditional fin stabilizer cannot work. Among existing equipments,only the effectiveness of U-type tanks is not affected by the speed of ship.But the volume of tanks is usually too large.U-type tanks can work well when its resonance frequency is close to that of ship.If the resonance frequency doesn’t match,the roll motion of ship might be strengthened. In order to solve these problems,the concept of zero speed fin stabilizer is brought forward.The dissertation is based on project supported by national science foundation of China:research on lift theory of ship bionic roll stabilization at zero speed(50 575048).The development of fin stabilizer at zero speed is summarized at first,then the key technology to develop fin stabilizer at zero speed is confirmed.The principle of fin stabilizer at zero speed is analyzed,and the structure and work mode of fin stabilizer with single wing and double wings are compared.Lift model is the foundation to study fin stabilizer at zero speed.A primary lift model is set up based on hydrodynamics.The principle to produce and change the forces on fin stabilizer is studied analytically,and the lift characteristic of fin stabilizer with single wing is analyzed based on this model.The simulation results indicate that fin stabilizer at zero speed is a load with large inertia,so its servo system must have excellent performance.The lift and torque model of Weis-Fogh mechanism are acquired based on potential theory,but only the open process of Weis-Fogh mechanism is analyzed in this model.In order to solve this problem,a practical lift model of close process is set up based on numerical analysis.The open and close character of lift and torque at different speed is simulated in Matlab.The concept of rotary fin stabilizer at zero speed is brought forward to overcome the disadvantage of existing single wing fin stabilizer at zero speed.The simulation results indicate that the performance of fin stabilizer at zero speed can be enhanced remarkably by this design.Fin stabilizer at zero speed works in non-steady flow.Only some primary lift models can be gained based on academic analysis.So these lift models must be corrected by the data of experiments. Because the flow field of fin stabilizer at zero speed is much different from that of traditional fin stabilizer,the scheme of hydrodynamic experiment must be studied deeply.A scheme is brought forward based on the analysis of flow field around fin stabilizer at zero speed.Some parameters of experiment is confirmed by similarity theory.The accuracy of data is guaranteed by these analysis.Traditional fin stabilizer is driven by electro-hydraulic servo system which is hard to maintain.Application of electro-servo system on fin stabilizer at zero speed is discussed to enhance the reliability of control system.Driving motor is selected based on load characteristic of fin stabilizer at zero speed.Due to the complicated working environment and load characteristic of fin stabilizer at zero speed,the CARIMA(Controlled Auto Regressive Integrated Moving Average) model of permanent magnet synchronous motor is established to realize generalized predictive control.The input and output constrains of electro-servo system are analyzed to improve the full load performance.The simulation results indicate that generalized predictive controller can improve the dynamic performance of servo system and enhance roll reduction ability of fin stabilizer at zero speed.When the ship is sailing,fin stabilizers move at the same speed.The task of servo system is to turn fin stabilizers to a certain angle.The lift is produced by interaction between fin stabilizer and water,and the energy comes from the engine of ship.When the ship is anchored,the energy for roll reduction is completely provided by servo system.The power of servo system is usually much lower than that of engine,so existing fin stabilizer at zero speed cannot work well when the intensity of ocean wave is very high.In order to reduce the power consumption when the effectiveness of roll reduction is ensured,both servo system and roll controller are optimized.For servo system,the optimal movement rule based on energy performance index is discussed with minimum principle.The method to drive is ensured to increase the value between lift and energy consumption.The theoretic analysis indicate that maximum lift can be gained by proper drive method with minimum energy.The disadvantage of opposite lift for roll reduction can also eliminated.For roll controller,frequency spectrum of random ocean wave is analyzed and random optimal controller with quadratic performance index is designed based on the extended state equations.Performance index weight matrices are optimized with genetic algorithm to find the best matching point between energy consumption and effect of roll reduction.To enhance the robustness of controller,random optimal control in different sea levels is realized by introducing parameter online adjusting rules for weight matrices.The simulation results indicate that expected effect of roll reduction can be acquired with least energy when weight matrices are fixed with external disturbance.更多还原