Metcalfe, AndrewGreen, DavidAbu Bakar, Mohd Aftar2019-06-182019-06-182016http://hdl.handle.net/2440/119564I begin with a brief introduction to dynamic systems, the identification of system parameters from records of input and output, and also wave energy converters which provide case studies to motivate the research. The dynamic systems discussed are categorized as linear or nonlinear dynamic systems. I present brief reviews of strategies for identification of dynamic systems which cover the history and also the areas of applications. The discretization of differential equations for dynamic systems is a recurrent theme and I consider forward, backward and central differences in detail for linear systems. The estimation techniques discussed are the principle of least squares, the Kalman filter and spectral analysis. Several system identification techniques for nonlinear dynamic systems in the time domain and in the frequency domain are presented and compared. The main focus of the thesis is estimation methods based on wavelets. I present some introduction to the wavelet transforms, which cover both continuous and discrete wavelet transforms. Wavelet methods for system identification of linear and nonlinear dynamic systems are discussed. Throughout this research, I have published four research articles guided by my supervisors. The first article discusses the wavelet based technique for linear system, and the technique was compared to the spectral analysis technique. The second article compare two types of wave energy converters, where the heaving buoy wave energy converter (HBWEC) is modelled as a linear system and the oscillating flap wave energy converter (OFWEC) as a nonlinear system. The frequency domain technique for system identification of nonlinear dynamic systems have been applied on the OFWEC model. Unscented Kalman filter have been discussed in the third article where the nonlinear OFWEC system have been used as the case study. A wavelet approach for nonlinear system identification has been discussed in the fourth article together with the probing technique. The probing technique was used to find the generalized frequency response functions of the nonlinear dynamic systems based on the nonlinear autoregressive with exogenous input (ARX) model. Both technique were compared for two weakly nonlinear oscillators, the Duffing and the Van der Pol. Once again, we selected the OFWEC system as a case study.waveletsystem identificationwave energydynamic systemoscillatorTheses