[ODE] Brakes and rotational damping

[Matthew Harmon]

>but doesn't the AMotor allow you to set a maximum torque<
It brings a wheel to a given velocity using (up to) a given max torque.  But
since I need to do my own gearbox simulation, etc. that method is a little
unsuitable.  I'm in more control simply applying torques myself.

> How are you calculating the new velocity of the wheel?<

For the "velocity based" brakes, we simply grab the current angular
velocity, reduce it by (brakeConstant * time * brakePressure) and set it
back to the body.  It works great, but doesn't seem like the "right" way to
go about it.  Still, it prevents us from worrying about "backlash".  I guess
my question is: Why is this "wrong" (if it is "wrong").

For the "counter-torque" based brakes, we apply a counter-torque to the body
and check to see if the body reversed direction.  If it did, we "lock" the
brakes.  Not that elegant, but it works as well.  Plus, this doesn't really
model how brakes work in real-life.

-----Original Message-----
From: J. Perkins [mailto:starkos at gmail.com]
Sent: Thursday, February 09, 2006 12:54 PM
To: Matthew Harmon
Cc: ode at q12.org
Subject: Re: [ODE] Brakes and rotational damping


On 2/9/06, Matthew Harmon <matt at ev-interactive.com> wrote:
> We need to control the wheel via "real" variable torque inputs.  The
> velocity-controlled system of the AMotor doesn't jive with reality in that
> sense.

It's been a while since I last looked at it, but doesn't the AMotor
allow you to set a maximum torque? I don't know about fiddling with
the velocity directly, that doesn't sound like the right answer. How
are you calculating the new velocity of the wheel? It seems like you
would have to get back to a torque at some point.

Jason