map problems with gmapping

asked 2017-12-01 03:07:21 -0500

marawy_alsakaf gravatar image

updated 2017-12-01 05:34:22 -0500

Hello all

i have a lidar lite v3 i rotate it with stepper motor to get planner lidar. i wrote a driver node, use it with gmapping node and odometry node. i get bad maps. they differ in each rotation. map image is attached.

any suggestions would be appreciated

edit retag flag offensive close merge delete


seems you have set your decay time to something :-)

What is the output of one single message of the laser? The way it looks, there seems something very wrong with your driver. But this could also be due to the decay time in the image...

mgruhler gravatar image mgruhler  ( 2017-12-01 09:30:54 -0500 )edit

@mig the output of laser is a point. i do not know what is wrong with it! the decay time lets points to stay visual more time (as i understand it)

marawy_alsakaf gravatar image marawy_alsakaf  ( 2017-12-01 10:06:27 -0500 )edit

How fast are you turning? Fast turns can result in bad maps.

jayess gravatar image jayess  ( 2017-12-01 15:02:40 -0500 )edit

@jayess how to calculate it ?

marawy_alsakaf gravatar image marawy_alsakaf  ( 2017-12-02 02:27:41 -0500 )edit

Well, you are driving it right? So you know how fast you're telling it to go? You don't need to calculate the speed. Just keep in mind that if you're getting bad results during a turn then you need to turn slower.

jayess gravatar image jayess  ( 2017-12-02 13:51:35 -0500 )edit

@jayess i don't drive the robot yet. the lidar rotates in its place. my stepper motor type is slow in its nature. it is 28BYJ-48.

marawy_alsakaf gravatar image marawy_alsakaf  ( 2017-12-03 00:44:50 -0500 )edit

How are you syncing the rotation of the laser to the scan message? The scan message format assumes that the first measurement in the message is at whatever angle the header indicates is the start. It looks like you do not sync measurements with rotation, or that the sync is not working correctly.

billy gravatar image billy  ( 2017-12-03 03:24:44 -0500 )edit

@billy i am using ros driver from here driver i edited it to be familiar with my lidar and stepper

marawy_alsakaf gravatar image marawy_alsakaf  ( 2017-12-03 06:06:06 -0500 )edit