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 Robotics / RCX / Java / 317
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Subject: 
Re: RotationNavigator accuracy
Newsgroups: 
lugnet.robotics.rcx.java
Date: 
Wed, 14 Jan 2004 15:34:59 GMT
Viewed: 
5523 times
  
How can this be, if it calculates with rotation sensor values,
wich do not depend on motor power?

rotation sensor counts tread rotation, but, because of skidding, the tank
doesn't turn exactly the same way as treads do

RotationNavigator nav=new RotationNavigator(2.64f, 9.5f, 1.0f);

The drive length is the length from one middle of the tread to the
middle of another.

rotation point position/drive length depends on tread width, center of weight
position, speed and geometry of treads and on friction coefficient, so your
value aproximates it very roughly. try to estimate it better by experimenting -
just let your tank perform series of turns and watch it.. then you should be
able to pinpoint and measure position of center of it's rotation.

Especially I do not understand, why the turning accuracy depends on
motor power and why the resulting turning angle is so different
depending on motor power.

i gues that's because of different slipping, but i am not sure

hope this helps

robert
Regards
Michael



Message has 1 Reply:
  Re: RotationNavigator accuracy
 
Hi Robert, thanks for your response. Indeed, the main problem seems to be slippage. The more speed the motors produce, the bigger the slippage is and the less is the resulting angle. Probably a tank is bad for odometric navigation. It is a pitty, (...) (21 years ago, 15-Jan-04, to lugnet.robotics.rcx.java)

Message is in Reply To:
  RotationNavigator accuracy
 
Hi, I just try the rotation navigator class and have some problems with turning accuracy. My robot is a tank with treads and moving without turning works well, travel() moves the correct distance. Turning with rotate() or gotoAngle() is problematic. (...) (21 years ago, 13-Jan-04, to lugnet.robotics.rcx.java)

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