【作者】 马磊；

【导师】 张显库；

【作者基本信息】 大连海事大学 ， 交通信息工程及控制， 2013， 博士

【摘要】 船舶作为一种重要的交通工具,在实施设计中虽然考虑了国际公约和国内法规有关稳性标准的规定,但波浪造成船舶失稳从而引发船舶倾覆的现象时有发生。目前船舶静态稳性纳入了稳性标准而动态稳性却未予以考虑,也就是说对于船舶在波浪中的稳性损失、运动瞬时状态及船舶与波浪遭遇状况缺少相关的考虑和研究。因此研究船舶在波浪激励下的复杂运动特性及鲁棒控制工程意义极为显著。船舶参数激励横摇可能导致船舶的大幅度横摇运动,威胁船舶、货物和海上人命安全。为了减小参数激励带来的不利因素,通过李亚普诺夫指数和功率谱对船舶在规则纵浪中运动的稳定性进行分析。从而分析船舶参数激励横摇运动的产生机理,不仅分析了船舶参数激励横摇产生混沌现象的条件,而且确定出船舶参数激励横摇运动的安全与危险区域。然后基于Backstepping算法、闭环增益成形算法及Lyapunov稳定性设计出减摇鳍控制器,并且在考虑一定的干扰后进行了仿真试验。仿真结果表明该控制策略对于消除船舶参数激励横摇系统的混沌现象是十分有效的,并且鲁棒性能令人满意。船舶参—强激励横摇比纯参数横摇可能导致船舶更大幅度的横摇运动,在主参数共振区内,较小的参数激励和强迫激励仍可能引起船舶大幅横摇,甚至倾覆,威胁船舶、货物和海上人命安全。为了减小参—强激励带来的不利因素,通过李亚普诺夫指数和功率谱对船舶在规则纵浪中运动的稳定性进行分析,找到参—强激励横摇运动的稳定和危险区域,以及对于船舶初始运动参数的变化关系。然后基于Backstepping算法、闭环增益成形算法及Lyapunov稳定性设计出非线性鲁棒控制器,并且在考虑一定的干扰后进行了仿真试验。仿真结果表明该控制策略对于消除船舶参—强横摇系统的混沌现象是十分有效的,并且鲁棒性能令人满意。在船舶初稳性高的时变性的影响下,随机纵浪也会对船舶的横摇稳定性造成较大的影响,特别在特征波长接近船长,且参数激励频率与船舶横摇固有频率之比为2时,船舶会发生大幅横摇不稳定运动,即为随机波条件下的参数激励横摇或参—强激励横摇。通过求解船舶在随机纵浪中主参数共振时的Lyapunov (?)旨数,分析船舶在随机纵浪条件下的主参数共振稳定性,并由此计算了船舶运动的稳定域与不稳定域,讨论了船舶横摇阻尼、随机波浪的中心频率,带宽等对船舶参数激励横摇运动稳定性的影响。同时,针对随机波条件下参数激励与参—强激励非线性运动设计出鲁棒控制器,从而减小船舶横摇危险,提高航行稳定性。更多还原

【Abstract】 As an important means of transport, the ship can satisfy the stability criteria required by the provisions of international conventions and domestic regulations in the design process, but often may capsize in the wave due to instability. At present, the stability criterion only considers the static stability without considering the dynamic stability and the research for stability loss, the instantaneous movement state and the wave encounter situation during navigating in the sea is lacked. Therefore the research for complex motion characteristics and robust control under the wave excitations has important engineering significance.Parametric excitation rolling can lead to dangerously large rolling motions, endangering the ship, cargo and crew. To decrease the influence caused by parametric resonance, stability of ships in longitudinal waves was then analyzed using Lyapunov characteristic exponents and power spectrum.The mechanism of parametric excitation rolling was explained by chaos theory. Not only the condition of chaos in parametric rolling was discussed, but also the safe and unsafe regions of target ships were then identified. Then the fin stabilizer controller was designed by using backstepping algorithm, closed-loop gain shaping algorithm,Lyapunov stability and simulation tests were carried out under certain disturbances. The simulation results show that the control effects are very effective for the elimination of chaos in the ship parametric rolling system and have satisfactory robust stability.Parametric-forced excitation rolling is more likely to cause dangerously large rolling motions, comparing with parametric excitation rolling, posing a danger to the ship, cargo and crew. In the principal parametric resonance zone, small parametric excitation and forced excitation can still generate large-amplitude roll, or even cause overturning. To decrease the influence caused by parametric and forced resonance, stability of ships in longitudinal waves was then analyzed using Lyapunov characteristic exponents and power spectrum. At the same time, stability and dangerous areas and the relationship between initial motion parameters and rolling movement can be discovered. Then the nonlinear robust controller was designed by using backstepping algorithm,closed-loop gain shaping algorithm,Lyapunov stability and simulation tests were carried out under certain disturbances. The simulation results show that the control effects are very effective for the elimination of chaos in the ship parametric and forced rolling system and have satisfactory robust stability.Under the effects of time-varying metacentric height of the ship, the random longitudinal wave can also a great impact on the ship’s rolling stability. Especially under the condition that the characteristic wavelength is close to the length of ship and the parameters excitation frequency double the rolling natural frequency, the ship will occur large and unstable rolling motion. That is parametric rolling and parametric-forced rolling under the random waves. By obtaining Lyapunov index during principal parametric resonance and analyzing principal parametric resonance stability, the stability domain and unstable domain were found.The influence of ship rolling damping, center frequency of random wave and bandwidth to parametric and parametric-forced excitation was discussed. Then the nonlinear robust controller was designed to reduce ship rolling risk and improve the stability of navigation.更多还原