Problem writing yaml parameters file

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1

Hi, I am trying to write the gmapping parameters file. I get this error, when I launch
user:~$ roslaunch my_mapping_launcher my_gmapping_launch.launch

Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

RLException: error loading tag:
file /home/user/catkin_ws/src/my_mapping_launcher/params/gmapping_params.yaml contains invalid YAML:
while parsing a block mapping
in “”, line 2, column 6:
$(arg_name_topic) : “scan_topic” …
^
expected , but found ‘’
in “”, line 2, column 40:
… arg_name_topic) : “scan_topic” $(default) : “kobuki/laser/scan”
^
XML is
The traceback for the exception was written to the log file

Please, I need suggestions how to manage:

 $(arg_name_topic) : "scan_topic"  $(default) : "kobuki/laser/scan" 
 $(arg_name_base) : "base_frame"  $(default) : "base_footprint"
 $(arg_name_odom) : "odom_frame"  $(default) : "odom"
 base_frame : $(arg_name_base)
 odom_frame : $(arg_name_odom)

and

remap :
 from : "scan" to : "$(arg_name_topic)

below the entire file:

 $(arg_name_topic) : "scan_topic"  $(default) : "kobuki/laser/scan" 
 $(arg_name_base) : "base_frame"  $(default) : "base_footprint"
 $(arg_name_odom) : "odom_frame"  $(default) : "odom"
 base_frame : $(arg_name_base)
 odom_frame : $(arg_name_odom)
 map_update_interval : 15.0
 maxRange : 8.0 
 sigma : 0.05 
 kernelSize : 1 
 lstep : 0.05 
 astep : 0.05 
 iterations : 5 
 lsigma : 0.075 
 ogain : 3.0 
 lskip : 0 
 minimumScore : 200 
 srr : 0.01 
 srt : 0.02 
 str : 0.01 
 stt : 0.02 
 linearUpdate : 0.5 
 angularUpdate : 0.436 
 temporalUpdate : -1.0 
 resampleThreshold : 0.5 
 particles : 80 

 xmin : -10.0
 ymin : -10.0
 xmax : 10.0
 ymax : 10.0

 delta : 0.05 
 llsamplerange : 0.01 
 llsamplestep : 0.01 
 lasamplerange : 0.005 
 lasamplestepvalue : 0.005 
remap :
 from : "scan" to : "$(arg_name_topic)

Thanks a lot
Salvatore

2

Hi Salvatore, the issue is that yaml files are used to setup the values and the way you wrote this one, it expects to have arguments filled.

Instead of

$(arg_name_topic) : "scan_topic"  $(default) : "kobuki/laser/scan" 
$(arg_name_base) : "base_frame"  $(default) : "base_footprint"
$(arg_name_odom) : "odom_frame"  $(default) : "odom"

You should write like:

scan_topic: "kobuki/laser/scan" 
base_frame: "base_footprint"
odom_frame: "odom"