View Full Version : Yaw rate estimation formulas and other things

02-15-2016, 08:39 PM

Here ya go. Fairly easy to solve if you start with vehicle speed instead of wheel speed. Wheel speed can be calculated from teh estimated yaw rate. Ran across this looking into physics models that would be used for electronic suspension control.

02-16-2016, 05:34 AM
Easy for you maybe, lol.

02-16-2016, 01:01 PM
the formula for yaw rate based on front wheels:

Vehicle speed in meters per second (Radius of wheel and tire in meters)
------------------------------------------------------------------------------------- = yaw rate in rads per second
width of front axle (Cosine(steering angle in rads))

So.. an example:
a car traveling 55mph or 25 m/s. that car has a steering input of 20 degrees or .349 rads with 26 inch diameter tires (radius ends up being .31 meters) and a front end width of 1.3 meters.

25(.31)/1.3(cos(.349)= 7.75/1.222

6.342 rads/s or a yaw rate of 363 degrees per second

from there, the yaw rate can be plugged into another equation to calculate wheel speed:

Front inside wheel speed in meters per second = vehicle speed m/s (front axle width in meters/2) cos(steering angle rads) * yaw rate rads/s

Example using yaw rate and such from above:
25-(1.3/2) cos(.349) * 6.342 = 25-.65(.9397)*6.342 = 25-.6108*6.342 = 25-3.8737 = 21.126 m/s inside wheel speed.

Outside wheel speed is calculated by adding the vehicle speed to the rest of teh equation.

Etc, etc.

try it out J-C-C