Calling a rosservice with args from a launch file

asked 2022-02-16 10:22:59 -0500

40 ●3 ●6 ●10

updated 2022-02-23 03:26:09 -0500

Hello there ! Hope u are doing well,

I'm trying to call a rosservice directly from a launch file, i used this questions to write my own node and it turned out like that:

<node pkg="rosservice" type="rosservice" name="chg_ctrl" args="call --wait /controller_manager/switch_controller 
    start_controllers:[joint_group_vel_controller]
    stop_controllers:[scaled_pos_joint_traj_controller]
    strictness:1
    start_asap:false
    timeout:0.0" />

It is almost working because i get this message:

ERROR: Incompatible arguments to call service:
Field [start_controllers] must be a list or tuple instead of: str
Provided arguments are:
 * start_controllers:[joint_group_vel_controller] (type str)
 * stop_controllers:[scaled_pos_joint_traj_controller] (type str)
 * strictness:1 (type str)
 * start_asap:false (type str)
 * timeout:0.0 (type str)

Service arguments are: [start_controllers stop_controllers strictness start_asap timeout]

I tried a couple of things and I can't get rid of this error, did anyone already tried someting like that ?

answered 2022-02-19 02:31:43 -0500

miura

1908 ●1 ●171 ●24 https://twitter.com/miura

updated 2022-02-23 16:46:11 -0500

I think the following method of using " to represent double quotation marks will work well.

<node pkg="rosservice" type="rosservice" name="chg_ctrl" args="call --wait /controller_manager/switch_controller 
    &quot;{ start_controllers: [joint_group_vel_controller],
    stop_controllers: [scaled_pos_joint_traj_controller],
    strictness: 1,
    start_asap: false,
    timeout: 0.0 }&quot;" />

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Comments

HI Miura, thank you for your suggestion ! Using your code it definitely improved the result but not quite enough:

ERROR: Incompatible arguments to call service:
No field name [strictnes:1]
Provided arguments are:
 * {'start_controllers': ['joint_group_vel_controller'], 'stop_controllers': ['scaled_pos_joint_traj_controller'], 'strictnes:1': None, 'start_asap:false': None, 'timeout:0.0': None} (type dict)