[ODE] Look at my Humanoid Example

Gene Ruebsamen gene at erachampion.com
Fri Feb 15 15:46:01 2002


Sure, if my code can help you in your game, feel free to use it!
I'm still trying to work out the stability issues, can anyone comment on my
previous post?  (Russ? =)

Thanks,

Gene

> -----Original Message-----
> From: McEvoy, Nick [mailto:nick.mcevoy@dsto.defence.gov.au]
> Sent: Thursday, February 14, 2002 1:12 PM
> To: 'gene@erachampion.com'
> Subject: RE:[ODE] Look at my Humanoid Example
>
>
> Ouch ... bit of a tumble .... cool stuff but !!!  Now you got to
> get him to
> stand up and walk.  :-)
>
> Sorry I haven't got any stability notes for you ... I just wanted to say
> keep up the good work.
>
> Your example code might come useful in my game one day (if that is ok with
> you of course) !  :-)
>
> Nick
> http://members.ozemail.com.au/~ndmcevoy/
> _________________________________________
>
> Message: 5
> From: Gene Ruebsamen <gene@erachampion.com>
> To: ode@q12.org
> Date: 13 Feb 2002 19:03:51 -0800
> Subject: [ODE] Look at my Humanoid Example
>
> Hello Everybody,
>
> I've created a humanoid figure in ODE. I used ball & socket joints for
> the arm and leg sockets, and hinges for the elbows, knees, and ankles.
>
> You can view a demo at: www.realtyroad.com/gene/
>
> My problem is... stability.  I am using ODE 0.3 and am having a horrible
> time with stability. I am dropping my humanoid from an altitude onto a
> staircase.  Depending upon the initial starting conditions (altitude,
> gravity, etc), either he will tumble down the staircase (as expected) or
> he will start to gyrate and oscillate (usually in the legs) and even
> explode.  The instability usually occurs when a joint hits its stop (as
> far as I can tell).
>
> At one time, I had the simulation fairly stable, using a global ERP of
> 0.1 and a global CFM of 0.01; however, looking through the docs, I think
> Russ recommended an ERP of between 0.2 and 0.9.  So I decided to set the
> ERP and CFM in each joint individually. I currently have it set at 0.5
> and 0.01 respectively.  Can I only achieve stability with such a low ERP
> of 0.1?  And if so, won't that introduce alot of joint error?
>
> Another question I have is with regards to motors.  When a powered joint
> reaches it's stop, must I shut off the motor (ie, set FMax to 0)?  Or is
> there a way to have the stop override the motor?  Right now, I have all
> my joints Fmax at 0; however, at one time I was running with FMax at
> 0.01 and velocity at 0 to simulate friction.
>
> The source is posted on the page above, in case anyone is curious, and
> wants to critique it for me... =) and hopefully help me solve the
> instability problems.
>
> Thanks!!
>
> Gene Ruebsamen
>