Study On Vibration Control Techniques For Platform Mounted Sonar In Flank Array

In this dissertation, vibration control for platform mounted sonar in flank array was studied. Combined with the project of National Defence Pre-study Foundation, some vibration control techniques for the platform were studied systematically and deeply.(1) Vibration isolation system for the platform was designed and produced by using two-stage isolation in which springs and rubbers were adopted as passive elements and one actuator were developed as active isolation actuator. Vibration acceleration transmissibility from hull board side to plate of the platform was formulated. Passive parameters are important to vibration control performance of the vibration isolation system. In order to optimize passive parameters of the system, minimization of the transmissibility was adopted as optimal objective, maximal entropy method was introduced to convert a non-differentiable objective programming to a differentiable one, the converted objective programming was solved with genetic algorithm because of high nonlinearity of its objective functions and restraints, parameters optimization for the vibration isolstion system was done.(2) Characteristics of giant magnetostrictive material were analyzed, giant magnetostrictive actuator was designed and prodeced, characteristics of the actuator was measured and analyzed, and corresponding Preisach mode to the actuator was developed. On the basis of combination between genetic algorithm and back propagation neural network, a new method to optimize neural network structure with genetic algorithm was developed, and the optimized neural network was used to identify the Preisach mode. A novel and useful control strategy based on iterative learning control was presented to realize linear input/output behavior of the actuator. This method can do online nonlinear compensation to the control current rapidly and dynamically.(3) Characteristics of fluid field and fluid-solid coupling between the vibration isolation system of the platform and the fluid field were analyzed, and dynamic equation of the vibration isolation system was formulated by using finite element method (FEM). The dynamic characteristics of the vibration isolation system under disturbance from ship hull board side were studied, and the vibration transmissibility was proposed. Influence of acceleration, velocity and displacement feedback to vibration isolation was studied to find the optimal feedback method.(4) Design methods of robust controller based on linear matrix inequation (LMI) were studied and H_∞ controller to the vibration isolation system was designed. A number of simulations of passive and active vibration control to the vibration isolation platform were made in MATLAB...