Vibration protection of laptop hard disk drives in harsh environmental conditions

Abstract

Ultra-portability and compact design of laptop computers have made them more vulnerable to harsh environments. Hard disk drives (HDDs) in particular, are critical components in laptop computers whose read/write performance is severely affected by excessive vibrations. Here we take a system-level approach to design an optimal vibration isolator so as to minimize the transmitted vibration to the HDD while the laptop chassis is confined within an allowable vibration travel. The laptop is modeled as a 3-dof lumped-parameter system and the base excitation is assumed Gaussian random vibration with zero mean and uniform power spectral density over the frequency range [0 2000] Hz. The problem is cast as a constrained optimization problem with two decision variables, namely isolation frequency and damping. A combination of analytical and numerical approaches is utilized to solve the constrained optimization problem. It is shown that the optimized isolation system could reduce the transmitted root-mean-square acceleration to the HDD by a factor of over four compared to a rigidly-mounted laptop. Furthermore, the methodology presented here is not case-specific and could be applied to the isolation system design of a wide range of systems.