Rotational Accelerometer Research Articles

MEMS-based accelerometers use in Hard Disk Drives

We describe the use of micro electro-mechanical systems (MEMS)-based accelerometers for the compensation of vibrations in commercial hard disk drives (HDDs). Using formal analysis of the HDD mechanics, effects of generic roto-translation on the head position are evaluated. It is shown that such effects can be compensated using feed forward compensation from a weighted sum of the signal provided by two linear and one rotational accelerometer, mounted on the HDD. Rotational acceleration has been obtained using a recently developed MEMS-based, low cost rotational accelerometer. Experimental results presented here show 20 dB disturbance reduction, achieved with a simple, variable gain feed-forward compensator.

Rejecting rotational disturbances on small disk drives using rotational accelerometers

Small disk drives are inherently designed for portable applications and thus must be able to reject external shock and vibration. This paper expands on previous efforts at using the signal from a rotational accelerometer to minimize the effects of these disturbances by dealing with several issues that come up: accelerometer beam resonances, low sample rate of the embedded servo on the disk drive, and widely varying accelerometer gains. The resulting algorithm is both simple and effective, making it practical for in-drive use. Experimental data is provided.

Thick film rotational accelerometer having two structurally integrated linear acceleration sensors

A rotational accelerometer has a pair of coplanar, operationally independent linear acceleration sensors. Coplanarity is provided by a unitary substrate which forms the base structure of the operationally independent linear acceleration sensors.

Ground tilt seismic spectrum measured with a new high sensitivity rotational accelerometer

We describe a new rotational accelerometer exhibiting excellent rotational acceleration sensitivity of 2–3×10−9 rad s−2/√Hz for frequencies below 2 Hz and increasing as the square of frequency for frequencies higher than 2 Hz. The sensitivity to horizontal linear accelerations and static tilts is 60 dB less than its rotational sensitivity. The accelerometer has been used to characterize the seismic ground tilt spectrum. Measurements of the performance of the device and of the seismic rotational spectrum are presented.

Rejecting Rotational Disturbances on Small Disk Drives Using Rotational Accelerometers

Small disk drives are inherently designed for portable applications and thus must be able to reject external shock and vibration. This paper expands on previous efforts at using the signal from a rotational accelerometer to minimize the the effects of these disturbances by dealing with several issues that come up; accelerometer beam resonances, low sample rate of the embedded servo on the disk drive, and widely varying accelerometer gains. The resulting algorithm is both simple and effective, making it practical for in drive use. Experimental data is provided.

Design of a prototype braking simulator

This paper describes the fundamental design aspets and subsequent development of an elaborate laboratory rig for the accurate measurement of braking system performance. It consists of a fully-instrumented moving stainless steel belt assembly with superimposed texture passing over end pulleys and driven by a variable speed motor. The test wheel forms part of a test axle having torisional strain gauges, a partial drum brake, a slip-ring assembly, a rotational accelerometer unit, a speed sensor and a variable-inertia disc mounted in line. The stimulator permits as many as ten variables to be preset independently prior to or during any test run. The rig can be used to simulate hydroplaning behaviour and to test tread pattern design, and also to evaluate the effectiveness of locked-wheel, constant slip and anti-skid pulsed braking systems. The entire wheel support system can be removed if desired, and a second super-structure substituted to evaluate the high-speed friction and wear behaviour of tread rubber and plastic block samples