Optimization of Sensing and Feedback Control for Vibration/Flutter of Rotating Disk by PZT Actuators via Air Coupled Pressure

Tianhong Yan,Bingfeng Ju,Jianqiang Han,Qing Li,Xinsheng Xu,Rongming Lin

doi:10.3390/s110303094

Abstract

In this paper, a feedback control mechanism and its optimization for rotating disk vibration/flutter via changes of air-coupled pressure generated using piezoelectric patch actuators are studied. A thin disk rotates in an enclosure, which is equipped with a feedback control loop consisting of a micro-sensor, a signal processor, a power amplifier, and several piezoelectric (PZT) actuator patches distributed on the cover of the enclosure. The actuator patches are mounted on the inner or the outer surfaces of the enclosure to produce necessary control force required through the airflow around the disk. The control mechanism for rotating disk flutter using enclosure surfaces bonded with sensors and piezoelectric actuators is thoroughly studied through analytical simulations. The sensor output is used to determine the amount of input to the actuator for controlling the response of the disk in a closed loop configuration. The dynamic stability of the disk-enclosure system, together with the feedback control loop, is analyzed as a complex eigenvalue problem, which is solved using Galerkin’s discretization procedure. The results show that the disk flutter can be reduced effectively with proper configurations of the control gain and the phase shift through the actuations of PZT patches. The effectiveness of different feedback control methods in altering system characteristics and system response has been investigated. The control capability, in terms of control gain, phase shift, and especially the physical configuration of actuator patches, are also evaluated by calculating the complex eigenvalues and the maximum displacement produced by the actuators. To achieve a optimal control performance, sizes, positions and shapes of PZT patches used need to be optimized and such optimization has been achieved through numerical simulations.

Highlights

Rotating disks are widely used in various engineering applications, such as computer data storage systems, turbines, gyroscopes, and annular saw blades, etc
Δθ = 75°, Zsum = 0.140 μm Feedback control mechanism using PZT patches via air-coupled pressure to suppress flutter of rotating disks in an air-filled enclosure has been studied in this paper
The control forces are related to the velocity induced by the PZT actuator, which is proportional to the vibration displacement of the enclosure cover

Summary

Introduction

Rotating disks are widely used in various engineering applications, such as computer data storage systems, turbines, gyroscopes, and annular saw blades, etc. With the rapid growth of data-storage density and increase of spindle motor speed in hard disk drivers (HDD), stability of rotating disks is becoming an important issue because of its significant contribution to track mis-registration and disk drive failure. A disk rotating at high speed can lose its stability due to the coupling of the disk structure with its surrounding airflow in such a way that it keeps absorbing mechanical energy from the airflow to quickly build its vibration amplitude until failure sets in. This is called aeroelastic instability, or flutter. A number of scientists have studied the aeroelastic stability (stability to self-excited vibrations) of spinning disks and obtained interesting results [2,3,4,5]

Methods

Results

Conclusion