Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Dynamic index / Yaw axis

Dynamic index / Yaw axis

Dynamic index / Yaw axis

I'm getting a bit confused with the the yaw axis of the vehicle, which I always assumed to be at the CG. I've recently come across a topic on the inertia match theory which (I think) suggests that there is a different point about which the car yaws, and subsequently the ratio of that to the rear axle distance determines the initial turn in response of the car.

Is this correct or am I missing something here?

Many thanks!

RE: Dynamic index / Yaw axis

The vehicle does not, in general, rotate around the cg, or any fixed axis at all. There may be a way of establishing that point of rotation by hand.The actual centre of rotation is at the centre of the curve, nowhere near the car at all. So you need to define what you mean.


Greg Locock

New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Dynamic index / Yaw axis

I understand that the 'turning' centre is far from the car, defined by slip angles and steering angle.

But the theory of 'inertia matching' is referring to the rotation of the car itself around some (yaw?) axis that's well within the car dimensions, so I am not sure what this axis is?

RE: Dynamic index / Yaw axis

What you are looking for is basically the zero lateral velocity point along the vehicle longitudinal axis.

For initial turn-in, it is the point along vehicle longitudinal axis where lateral acceleration is zero.
The dynamic index can be derived from this condition.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close