An Investigation of the Feasibility of Microscale Adaptive Passive Vibration Neutralizers

Abstract

This thesis concerns the control of an adaptive passive vibration neutralizer and the feasibility of miniaturizing this type of tunable vibration neutralizer for small-scale applications. <p> An analytical model for the adaptive passive vibration neutralizer is derived and compared to experimental results. A tuning algorithm is derived from a curve-fit of experimental tests on the specific neutralizer. A more generic tuning algorithm is also developed, which does not require testing of the neutralizer for optimal control. Both tuning algorithms are tested using a chirp forcing function to simulate drift in the excitation frequency of a host structure. Computer simulation and experimental results are given for these tests. <p> A novel low-cost, small-scale vibration neutralizer is constructed from packing bubble-wrap. Analytical models for the stiffness are calculated, and experimental data is used to derive a damped mass-spring model. <p> Miniaturization of vibration neutralizers is described, and many of the pitfalls in design are discussed. Theoretical tuning frequencies of possible adaptive passive vibration neutralizers at different scales are included. The goal for these miniaturized vibration neutralizers is vibration control in computer hard drives. <p> A hard drive is analyzed for vibration problems. Included are plots of the velocities of the read-write head and spindle. Limitations of the measurement equipment are discussed, and directions for future work on small-scale tunable vibration neutralizers are outlined.