The Symbolic Space Method For Natural Character Of Dynamic System

The analysis of system intrinsic characteristic is foundation of vibration problem and fault diagnose. It is difficult to accurately modeling for the complex dynamic structure, since then, the new analysis of system intrinsic characteristic without accurate modeling is in dire need of.The response of the system is a reflection of dynamic characteristics for structure. From the response sequences which inspired in transient forces, we bring in the complexity algorithm proposed by Lempel and Ziv of complexity theory .Based on symbol group of Lempel-Ziv complexity, the symbol sequence and symbol group are been got from graining the dynamic response of vibration system. The symbolic space can reflect the dynamic system. The coefficient matrix of symbolic space contain frequency information of the structure, the frequency are singular value of the matrix.The major processes mentioned in this paper are as follows:Firstly, it introduces the response analysis theory of vibration system, symbolization of response sequences.Secondly, based on symbol group of Lempel-Ziv complexity, the symbol sequence and symbol group are been got from graining the dynamic response of vibration system. The symbol space will be making up by plus all symbol groups. Then we curtail the coefficient matrix of vector in symbol space.Lastly, calculate the dynamic response of a T board, obtain the coefficient matrix and it's eigenvalue of the symbol vector, the eigenvalue approach to that by modal analysis.This method could obtain character of vibration system. The analysis merely uses dynamic response without knowing math model. It also provides a new way for parameter identification of vibration system and vibration control as well as fault diagnosis.