Navigation / location problems

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Navigation / location problems

Postby rapsac » Fri Mar 21, 2008 10:48 am

Hi,

I am trying to make a robot that can move around with bluetooth. The bluetooth part works fine, but the main problem is how to callibrated the robot for good movement.

The robot rotates almost perfect (maybe a half degree every 360 degrees off), but the distance that he travels is not the same everytime. So the 2 main questions are :

1. How to callulate the _wheeldiameter? (56mm on the tires seems abit off)
2. If the robot stops, it makes a little click (not like the clicking sound) and moves a bit forward. Is there away to make it stop smooth?

Extra information:
- Using the TachoNavigator
- Played around with differnt values
- Slow motor speed (210)

Cheers,

rap
rapsac
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Postby roger » Fri Mar 21, 2008 9:02 pm

Hi rap,
I am trying to make a robot that can move around with bluetooth. The bluetooth part works fine, but the main problem is how to callibrated the robot for good movement.
I am curious - are you using ICommand? if not, how are you using bluetooth?
The robot rotates almost perfect (maybe a half degree every 360 degrees off), but the distance that he travels is not the same everytime.
Strange. The Pilot class, which TachoNavigator uses, is usually very consistent traveling a fixed distance. Since the robot rotation angle depends on both the wheel diameter and the track width, it is best to first experiment with the wheel diameter till the travel distance is correct, then adjust the track width to get the rotation angle right. You will get different results depending on the surface: hard wood or deep carpet.
If the robot stops, it makes a little click (not like the clicking sound) and moves a bit forward. Is there away to make it stop smooth?
That last move is the motor trying to get its rotation accurate. The latest version of Motor makes a smoother stop.
Roger
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Postby rapsac » Sat Mar 22, 2008 3:52 pm

Hi,

thanks for the reply.

I am not using Icommand, but the bluecove if i am correct. I cant confirm that right now, you have to wait till wensday i think.

But i think you right about the the wheel diameter and trackwidth. I did that the otherway around, so first get the correct trackwidth till i got a nice angle. I think that is where it went wrong.

I am going to test it out, and i will share the results

rap
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