[ODE] FDir1 and Slip for car wheels

[Jon Watte]

Yes, I use Ackerman-style steering (that's another good tip I 
got off this list and forgot to include in the list of tips). 
The actual proportion between inner/outer wheel is tuneable, 
rather than being measured/calculated, to allow for various 
degrees of toe-in during steering. Applying the same degree of 
twist to both wheels would result in negative toe-in while 
steering.

However, my point was that the wheel will rotate around its 
axis, and thus what's "front" of the wheel body when you set 
up your system will very quickly be "down" of the wheel body; 
after traveling just 1/4 revolution. Beacuse the wheel has a 
contact with the ground, "down" cross "up" would not generate 
a useable fdir2, so the fdir1 you supply needs to be something 
that's as orthogonal to your contact as possible.

Cheers,

		/ h+




-----Original Message-----
From: root at garbled.net [mailto:root at garbled.net]
Sent: Tuesday, December 07, 2004 9:34 PM
To: Jon Watte
Cc: Mailing List) <ode at q12.org>
Subject: RE: [ODE] FDir1 and Slip for car wheels



On 08-Dec-2004 Jon Watte wrote:
> 2) The "front" of the wheel isn't necessarily the "front" of the car, 
> as the wheel both turns and rotates. I extract "front" and "up" of the 
> wheel, and then, to calculate fdir1, I do this:

Curious, do you use an ackerman steering system on your cars, or is that mostly
irrelevant for the purposes of an ODE simulation?

---
Tim Rightnour <root at garbled.net>
NetBSD: Free multi-architecture OS http://www.netbsd.org/
Genecys: Open Source 3D MMORPG: http://www.genecys.org/