ROS transform/synchronization issues

asked 2018-07-30 10:14:00 -0600

sparkas gravatar image

Hello everyone,

I have a robot equipped with a stereo camera for perception and an gyroscope/odometer setup for localization. We have different machines in our robot (one running the perception and the other the localization). For a correct transform of the detected objects using the localization we tried synchronizing our machines using chrony via ntp. In our code we then 'waitForTransform()' and 'lookupTransform()' in order to get the correct transform using the camera picture's time stamp. For some reason the objects seem to 'wander' when visualizing them meaning that they get transformed using a different orientation than at the time of the image, but 'ntpdate -q machine1' returns:

server 10.1.1.102, stratum 9, offset -0.000060, delay 0.02617
11 Feb 17:13:38 ntpdate[22516]: adjust time server 10.1.1.102 offset -0.000060 sec

which should be sufficient. Unfortunately I do not really know where to look or how to start debugging tf. Any ideas would be much appreciated!

Greetings, sparkas

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