【作者】 李小波；

【导师】 徐克宝；

【作者基本信息】 山东科技大学 ， 机械电子工程， 2008， 博士

【摘要】 提高海浪观测和预报能力,最大限度地降低海浪所带来的灾难性损失,是我国海洋监测高新技术发展的重要目标之一,对海浪的更精确的把握是一个具有普遍意义的问题。本文以已有的不规则海浪特征研究为基础,结合随机过程分析、非线性系统分析和小波理论的最新成果,为解决这一难题提供新的技术思路。本文提出了利用子母式浮标阵列进行海浪测量的方法。子母式浮标阵列由母浮标和四个对称分布的子浮标按照星型分布,母浮标由锚链固定于海底,子浮标与海底没有链接,仅通过连接杆铰接到母浮标上。在海浪作用过程中,子浮标绕母浮标中心轴上下运动,子母浮标之间不存在周向运动,它们的相对位置是固定的。并且,子浮标不受海底锚缆的牵制,从而具有很好的漂浮性能,能够测到海浪的高频部分波形。正是由于采用子母式结构,才大大减小了锚系对子浮标的约束作用,使子浮标能很好地随波浪运动。加上子浮标自身体积、质量都比较小,随波性得到了进一步改善,系统的测量精度可大幅度地得到提高。结合目前国内外的常规算法,通过浮标以及锚泊系统的受力分析,在实测数据的基础上,提出了一种新型的海浪信号反演谱,将该谱对海浪的谱估计与真实谱进行比较,发现该谱能够很好地逼近实测谱,曲线平滑,误差很小,并且参数确定简单,运算量小。进一步的仿真分析表明,在同一海况下,将该谱与PM谱、文氏谱进行相互印证,发现结果非常接近,更加证明了该谱的有效性。利用该反演谱作为靶谱,基于长峰波海浪理论,充分考虑了海浪随机性的前提下,构造海浪函数发生器进行海浪模拟,这对于缺少实测数据或者实测数据难以获得的现实情况具有重要意义。利用谱分析法对海浪的统计特性进行了分析。海浪谱是描述海浪的基本方法。在海洋学中,利用谱以随机过程来描述海浪是进行海浪研究的主要途径之一。它基于内部组成波的概念描述了海浪平均能量在内部频率或波数空间中的分布,它不仅能揭示海浪的内部结构,而且还可以提供海浪外观统计特征的信息,故海浪频谱的研究仍然是海浪研究的中心问题。基于小波理论,提出了能量自适应阈值算法,利用该算法对海浪信号进行时频分析,并充分利用Fourier变换在频域上的高分辨率,将小波变换与傅立叶变换结合起来,深入分析了海浪内在的非线性、非稳态特性。作为海浪实测系统的具体实现形式,本文建立了基于MEMS加速度传感器的高随波性子母式浮标系统,该系统具有体积小、重量轻,测量精度高的特点,从系统的稳定、安全、可靠工作,到超低功耗、高随波性等方面都进行了较为详细地论述。更多还原

【Abstract】 Improve the capability of waves’ observation and forecasting, and minimize the devastating loss caused by the ocean wave, is one of the important goals of high-tech development of marine monitoring in our country. The more accurate grasp of ocean wave is a universal problem. Based on the known characteristic study of irregular ocean waves, this paper put new technical ideas to solve the technical problems by combining random process analysis, nonlinear system analysis and the latest results of wavelet theory.This paper proposed wave-measuring method by using mother-son buoy arrays. The buoy array is made of the mother and four buoys which are symmetric distribution. The mother buoy is fixed in the seabed by chain, and son buoys do not link to the seabed, and only through the hinge connecting rod to the mother buoy. In the role of the waves, the son buoys move along the center axis around the mother buoy, and there is no motion between the mother buoy and the son ones. And their relative position is fixed. In addition, the son buoys are not linked to the seabed, which has a very good floating performance, and can be able to test some of the high-frequency wave form. It is due to the use of mother-son structure, it greatly reduces the mooring force to the son buoys, so the son buoys can move with waves better. In addition, the son buoys have small size, the quality being relatively small, the flowability and the measurement accuracy of the system can be enhanced.With given algorithm, it has analyzed the force on the buoy and mooring system. Based on real data, put forward a sort of new sea wave inversion spectra, and compare it with the true one, it is found that the spectrum can be a good approximation of the measured spectra, and it. has smooth curves and the error is very small, parameter-confirmation is simple and the computing amount of is small. And further, under the same condition, comparing the new inversion spectra with PM spectra and WEN spectra, then found it was close to them. Simulate ocean wave by the new spectra, construct ocean wave function generator, and found it’s fast Fourier results are accord with our ocean, and again this proved the new spectra is valid.Using spectral analysis, it analyzed the statistical properties of the waves. Wave spectrum is the basic method to describe the waves. In oceanography, using spectral analysis as a random process to describe the waves is one of the main study. It is based on the internal composition- wave concept to describe the distribution of the waves average energy in the internal wave number space or frequency, it can not only reveal the internal structure of the waves, but also to provide the appearance of the demographic characteristics of the waves, therefore, the and the wave spectrum research remains the central issue.Based on wavelet theory, the paper put forward the energy-adaptive threshold algorithms, and used it to do time-frequency analysis on the waves, and made full use of the Fourier transform high-resolution in the frequency domain. Combined the wavelet transform with Fourier Transform, it analyzed the inherent non-linear, non-steady-state properties of the ocean wave deep.As the specific realization form of the waves measuring system, the paper designed the mother-son waves measuring system with high flowability, based on MEMS accelerometer. It has the following characteristic: a small size, light weight, high accuracy. The detailed design was carried out from the stabilization, safety, reliableness to ultra-low power, high flowability.更多还原