Dynamic Modeling And Self-converging Control Of Electromagnetic Suspension Vibration Isolator

Vibration control is a very important issue in the field of the ship. Because once the installation of the traditional passive vibration isolation is completed, it is difficult to change parameters. So it does not have strong adaptability for the changes of vibration objects and seismic focus. Furthermore, passive vibration isolation can not guarantee the performance of vibration isolation in low frequency. Compared with this, active vibration isolation is self-adaptive and has good control effect in low frequency. So it becomes a research hotspot gradually. This paper conducts the research on the theory and experiment related to active vibration isolation, based on self-designed version 2 of Electromagnetic Suspension Vibration Isolator (2nd ESVI).Three expressions of evaluation indices of vibration isolation (Vibration Level Difference, Insertion Loss and Force Transmissibility) are derived in detail. A constant difference between the three indices is obtained under certain conditions. An accurately and full method that reflects the combined effect of active and passive vibration isolation is proposed. Then the designs of 2nd ESVI and flexible base are introduced. The relationship between the evaluation indices is verified through the experimental results, and the relationship between the three indices and damping, stiffness, quality of the system is researched through simulations.The actuator in 2nd ESVI is an electromagnetic actuator. The electromagnetic force is controlled by controlling the input current of the electromagnet. In order to carry out effective active vibration control, the relationship between the electromagnetic force and current, gap is needed to establish. The experimental modeling method of electromagnetic force is improved. The relationship between the dynamic electromagnetic force and current, gap is established through experiments. The more accurate dynamic electromagnetic force model considering the frequency factor is obtained. A self-optimizing feed-forward control scheme is proposed and good experimental results are achieved in the electromagnetic suspension vibration isolation system.In order to resolve the problem of modeling the secondary path in the active vibration control algorithm, an self-converging feed-forward control algorithm without the secondary path model is presented based on the geometric analysis of filtered x Least Mean Square (filtered x-LMS) algorithm. Through the experiments on the electromagnetic suspension vibration isolation experimental platform, good experimental results are achieved in the 5.0 Hz - 15.0Hz band. Finally the impact on convergence speed of the block-normalized adaptive filtering algorithms is studied.