A Automotive project to determine road gradient during braking

[Tim Steer]

Hello Forum,

Does anybody have suggestions as to how we can use IMU's (accelerometers and gyros) to determine the gradient of a road during a braking event. We have wheel speed inputs so can calculate decelerations independently from the IMU.

Thank You

Tim

 

[billy_joule]

If wheel speed is constant but acceleration is being measured what are the possible causes and how could you distinguish them?

 

[A.T.]

We have wheel speed inputs so can calculate decelerations independently from the IMU.

Are you assuming the wheels don't slip during the acceleration? If yes then you should have enough information. Draw the vector diagram for the accelerations.

 

[billy_joule]

Are you assuming the wheels don't slip during the acceleration?

Yes, like most car speedos do. Though if it's a heavy braking test then skidding is likely so it maybe a problem.
I'm not sure how race cars get around this? GPS?

 

[Tim Steer]

Yes the assumption is no wheel slip. Can anybody add anything more practical like, we need a gyro and accelerometer ?