Phidgets spatial 3/3/3

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viccos
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Phidgets spatial 3/3/3

Postby viccos » Tue Apr 09, 2013 9:51 am

I am trying to use the phidget spatial 3/3/3 as a position sensor for a mobile robot.

The way I am doing is by integrating twice the acceleration. THe formulas I have for calculating position are (1 means the axis):

a= (9,81*a1)
v = vo + a1t
x = x0 + v + (a*t*t/2)

But the error grows unbounded really fast. I am working with a rate of 0.032 s. Also, sometimes I get some negative velocities (which is not suppose to happen). I know that the error is cummulative, but how can I get the best of this sensor in a sample of, let´s say, 10 seconds? How precise am I going to be?

I need to get the best position I can from the sensor. I am working in c#

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Patrick
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Re: Phidgets spatial 3/3/3

Postby Patrick » Tue Apr 09, 2013 10:10 am

Have a look at the wireframe c# example for some examples. The errors will accumulate very quickly. The only way to fight this is by using a Kalman or like filter and fusing in data from other sensors like the compass and a GPS. The implementation of this is beyond the scope of this forum, but have a look at quadcopter algorithms - these are becoming very common on the web, and these use kalman filters.

-Patrick


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