Re: [PlayerStage-Gazebo] Pioneer 2AT heading

[Jordi <mu...@gm...>]

Actually It is done this way:
D1=  distace travelled by left wheel  (time * radius * angular velocity of 
left wheel)
D2=  distance  travelled by right wheel

how much we rotated= (D2 - D1) / separation betwen wheels

how much we go on X axis =(d1 + d2) / 2) * cosine of how much we rotated
how much we go on Y axis =(d1 + d2) / 2) * sine of how much we rotated


All those things are positions
For velocity just divide distances by time since last call.


--
Jordi Polo


> The best way to simulate the AT's odometers would be to look at the
> rotations (or integrate rotational velocities) of the individual wheel
> objects, if you can do that in the current system. (And each pair of
> wheels, left and right, ought to be synchronized, so you could just look at
> the two front wheels, or whichever one moved the most (front or back), or
> something.)
>
> Reed
>
> Jordi wrote:
> > I guess that the authors wanted to simulate a typical odometric system.
> > Using the body methods is just too perfect and it's information that
> > can't be accessed in a real model (well, may be available if you have a
> > gyroscope on board).
> > As Pioneer (the real robot) uses odometry for getting information of
> > position (I guess, I don't have one), the model also use simulated
> > odometry.
> >
> > Anyway 470- 360 =110 degrees of difference between ideal data and
> > simulated data is far too much. Are you just using wxgazebo?
> >
> > --
> > Jordi Polo
> >
> >> After looking closer at the model created I noticed that the authors
> >> didn't take advantage of such functions like GetPose or GetLinearVel and
> >> GetAngularVel for this->chassis but instead calculated the values using
> >> methods that assume the base has two wheels...
> >>
> >> Was there a reason for this?
> >>
> >> It seems that if I use these functions of the Body Class I get the
> >> heading and linear/angular velocities desired.
> >>
> >> Thanks
> >> Sean
> >>
> >> Sean Verret wrote:
> >>> Hi there,
> >>>
> >>> I've been running a simple Pioneer2AT model in a world with no
> >>> obstacles.  I noticed that if you rotate the robot 360 degrees, using
> >>> the position widget it in fact states that the robot has rotated closer
> >>> to 470 degrees.
> >>>
> >>> Does anyone else have this problem?  Could I be missing something in my
> >>> world file?
> >>>
> >>> Thanks
> >>> Sean
> >>>
> >>> Using Tomcat but need to do more? Need to support web services,
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> Using Tomcat but need to do more? Need to support web services, security?
> Get stuff done quickly with pre-integrated technology to make your job
> easier Download IBM WebSphere Application Server v.1.0.1 based on Apache
> Geronimo
> http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
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