Using an ARS to Measure RPM or Wheel Speed

Purpose:

The relationship between angular rate and rotation rate in RPM is a simple one, allowing for easy conversion from one unit of measurement to the other.  This conversion can be applied in SLICEWare or DataPRO to display ARS measurement values as RPM (revolutions per minute) rather than the standard degrees per second (deg/sec) or radians per second (rad/sec).  With a bit more effort and some other information about the system, you can convert the angular rate values to velocity in KPH or MPH, and even distance traveled by a rolling wheel.

When making these adjustments, you will configure the sensor settings as seen here:

RPM Specifications for DTS ARS Models:

The following table provides the rotational range of ARS PRO/HG, ARS3 PRO, 6DX PRO, and 6DX G2 sensors.

Angular Rate to RPM Conversion:

To display RPM values in SLICEWare when using an ARS, you will adjust the Sensitivity value in the sensor profile setting to account for the conversion.  The adjusted Sensitivity value is:

For Desired Range, you will change to the Rotational Range value listed in the above table for your ARS model.  The new Units (EU) will be RPM.

Angular Rate to Wheel Speed (MPH) Sensitivity Conversion:

To convert angular rate data to velocity based on wheel speed, you will need another piece of information about the system under test:

• Rolling Circumference of the Wheel (ft)
  • This is the circumference of the wheel in-use, accounting for compression of materials during rotation

To get the SLICEWare sensor profile Sensitivity in MPH:

For Desired Range, the following calculation can be used for conversion:

The new Units (EU) will be in MPH.