Re: [simspark-devel] new problem of new server

[Yuan X. <xuy...@gm...>]

Hi Joschka,

Also about the joint angle restriction,
it seems that when the joint angle is out of range, ODE will apply a
force to restrict it,
but the motor is still working, then resulting the joint angle
concussion, at last the whole robot disjointed.
After restricting the desired joint angle in our agent (i.e. the robot
should not try to turn an angle out of the range),
the simulation became stable.
However, if a robot missing the restriction itself, the simulation may
interrupted by it...
I think we can set the motor velocity to zero while the joint is out of range.

2007/6/19, Yuan Xu <xuy...@gm...>:
> Hi Joschka,
>
> After some testing, I think it is hard to got a good balance by
> turning global parameters,
> and the results depends on many factors: such as the robot mass, robot
> control ( high or low gain ).
>
> The ODE parameters effects the robot performance greatly, maybe teams
> do not like change at this time...
>
>
> [...]
> >
> > Increasing the global CFM is recommended for numerical stability, but it
> > may also result in softer joints in general, including the contact
> > joints. So if the parameter is increased too much, the ball and the
> > robots might sink into the ground! It's difficult, but it might be worth
> > playing around with the global CFM and ERP parameters, and maybe also
> > try to set local CFM and ERP values for the individual joints (or joint
> > stops). As a start, one could try sth. like
> >
> > world.setCFM(0.01)
> > world.setERP(0.9)
> >
> > in spark.rb, and see if it changes the stability of the simulation in a
> > positive way.
> >
>
>
>
> --
> Best wishes!
>
> Xu Yuan
> School of Automation
> Southeast University, Nanjing, China
>
> mail:   xuy...@gm...
>           xy...@ya...
> web:   http://xuyuan.cn.googlepages.com
> --------------------------------------------------
>


-- 
Best wishes!

Xu Yuan
School of Automation
Southeast University, Nanjing, China

mail:   xuy...@gm...
          xy...@ya...
web:   http://xuyuan.cn.googlepages.com
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