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You made some really large (and some even absurd) changes to some of the gmapping parameters, which may lead to the observed behaviour...

<param name="linearUpdate" value="0.01"/>
<param name="angularUpdate" value="0.01"/>
<param name="temporalUpdate" value="0.1"/>

These settings will force an update with almost every new scan and benefit the accumulation of even small errors in scan matching. This may be the main culprit and what makes your odometry mostly meaningless.

Try setting these parameters closer to the default like linear 0.2, angular 0.3 and especially temporal to something like 5-10 (or even -1 to turn it off completely).

<param name="particles" value="1"/>

Now regarding the "even absurd" part of your config. GMapping is a particle filter based SLAM approach. So it needs some particles with each representing one "guess" of the current position and traveled path. When setting particles to 1 you are in fact doing dead reckoning based on scan matching, odometry and even some (intentionally!) added noise. You should set particles to at least the default value of 30 or even better higher! (Whatever your CPU can support. We typically use between 50 and 80 particles.)

In general i would advise you to start of with the default GMapping config and change only those parameters you really need and even than not by a factor of over 30 to begin with...

You made some really large (and some even absurd) changes to some of the gmapping parameters, which may lead to the observed behaviour...

<param name="linearUpdate" value="0.01"/>
<param name="angularUpdate" value="0.01"/>
<param name="temporalUpdate" value="0.1"/>

These settings will force an update with almost every new scan and benefit the accumulation of even small errors in scan matching. This may be the main culprit and what makes your odometry mostly meaningless.

Try setting these parameters closer to the default like linear 0.2, angular 0.3 and especially temporal to something like 5-10 (or even -1 to turn it off completely).

<param name="particles" value="1"/>

Now regarding the "even absurd" part of your config. GMapping is a particle filter based SLAM approach. So it needs some particles with each representing one "guess" of the current position and traveled path. When setting particles to 1 you are in fact doing dead reckoning based on scan matching, odometry and even some (intentionally!) added noise. You should set particles to at least the default value of 30 or even better higher! (Whatever your CPU can support. We typically use between 50 and 80 particles.)

In general i would advise you to start of with the default GMapping config and change only those parameters you really need and even than then not by a factor of over 30 to begin with...