'rosApplyTransfrom' gives error even on passing the correct arguments type

Question

Dhruv Thakkar 2022-6-1

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1731470-rosapplytransfrom-gives-error-even-on-passing-the-correct-arguments-type

回答： Cam Salzberger 2022-6-16

I am trying to tranfrom messages from one frame to another, from a rosbag, in the following fashion.

tranF = getTransform(bagfile,'targetFrame','world');
worldPose  = readMessages(select(bagfile,'Topic','/vrpn_client_node/targetFrame/pose' ),'DataFormat','struct');
rosApplyTransform(tranF,worldPose)

But upon doing so I get the following error. Can anyone point me in the right direction?

Error using rosApplyTransform
Expected tfmsg to be one of these types:
struct
Instead its type was ros.msg.geometry_msgs.TransformStamped.
Error in rosApplyTransform (line 40)
    validateattributes(tfmsg, {'struct'},{'scalar'},'rosApplyTransform','tfmsg');

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Cam Salzberger 2022-6-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1731470-rosapplytransfrom-gives-error-even-on-passing-the-correct-arguments-type#answer_986960

Hello Dhruv,

The issue is that the output of "getTransform" is a message object, while the output of "readMessages" is a message struct, and "rosApplyTransform" expects both to be message structs.

Unfortunately, I'm not able to find a way to get a message struct out of "getTransform", which would be the idea situation. So the best workaround for now is probably to get an object out of "readMessages" as well (remove the DataFormat=struct name-value pair), and then use the "apply" function rather than "rosApplyTransform".

-Cam