X
Y
Z
Oscilloscope
Determining the Axis of Vibration
4
Determining the Axis of Vibration
The orientation of the accelerometer can be determined by the 3-axis label on the small accelerometer
board. The direction of the arrows corresponds to the axis which the acceleration is measured. The Z-
direction is measured normal to, or coming out of, the board.
Figure 7. Acceleration Axis
For haptic applications, the axis of vibration is determined by the motion of the actuator. Take for example
a DC motor that spins around the X axis and creates force in the Y and Z axes. In this case, measure
vibration by connecting to the Y and Z test points of the accelerometer.
The axis of vibration can often be found in the actuator datasheet; if not, the axis is usually easily
determined by measuring all axes and finding the axis with the highest acceleration. Below are example
diagrams of ERM, LRA, and Piezo actuators and their axes of vibration.
NOTE:
Not all actuators will have these same axes of vibration.
4.1
Eccentric Rotating Mass
The ERM motor in
spins around the X axis and produces rotational vibration in the YZ plane.
Acceleration can be observed on the Y and Z accelerometer channels.
Figure 8. ERM Axes of Vibration
Figure 9. Y and Z Axes Acceleration Measurement
7
SLOU402 – June 2015
DRV-ACC16-EVM Accelerometer User’s Guide
Copyright © 2015, Texas Instruments Incorporated