Re: Re: Problem with Euler Angles

Frans wrote:
> Great! This routine works perfectly on my test walk.
> (I will have to check a few values formatted as "?")
>
The DecimalFormat.format(double arg) function creates a string equal to "?"
when the argument is equal to Double.NaN.
The Double.NaN value occurs when the argument of the asin( ) function is
outside of the range from {-1, 1}, such as 1.0000000001.
I have added a check in the routine to force the argument of asin( ) be in
the valid range so the Double.NaN does not occur.

> Do you care to publish the routine on the Wiki pages? I can make the
> page if you don't have time.
>
There is a new Wiki page showing the Inclinometer Angle Calculations.

Olivier wrote:
>Thanks Frans for this feedback. I will add the routines of Mike into the
>Controller class and document them, so that anyone can use them easily.
>This will be part of Webots 4.0.19, which I hope to release next tuesday.
>
The noise error added during the contest should probably be added to the
resultant X,Y, and Z angles and not to the OpenGL matrix elements.  If the
noise is added to the matrix elements the actual error in the computed
angles will vary with the angle and be a maximum of (2*NoiseOfElement) at
angle=PI/4, and a minimum close to 0 at angle=0 and PI/2.
angle=PI/4,    atan2(1+noise / 1+noise)
angle=0, PI/2,    atan2(largevalue+noise / 0+noise ),  atan2(0+noise /
largevalue+noise)

Also, the argument of asin( ) should be forced into the valid range of {-1,
1} to prevent returning an angle of Double.NaN.

Mike Jost



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