How can I handle the array type of ROS messages ?

Question

Jaehyeon Im 2019-5-13

1
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/461711-how-can-i-handle-the-array-type-of-ros-messages

编辑： Jaehyeon Im 2019-5-14

采纳的回答： Cam Salzberger

Hi MathWorks team,

I wonder that how can I handle the array type of ROS messages for subscribing or publishing.

For example, I want to publish [ 350 x 2 ] type of ROS message.

To publish ROS msg, I have to assign my data to ROS-supported-type using "Blank Message Block" like std_msgs/Float64 or customized message type.

It seems like that I have to use "std_msgs/Float64MultiArray" type to publish [ 350 x 2 ] ROS msg.

I want to know that this is right. And if it is right or not, please let me know the way.

Thanks !

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Answer 1

Cam Salzberger 2019-5-13

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https://ww2.mathworks.cn/matlabcentral/answers/461711-how-can-i-handle-the-array-type-of-ros-messages#answer_374748

编辑：Cam Salzberger 2019-5-13

Hello Jaehyeon,

It looks like the std_msgs/Float64MultiArray should be able to handle the array of data you are looking to provide it. Note, however, that none of the data shaping is done automatically. You will need to convert it to a 1-D array to provide to the "Data" field of the Float64MultiArray message, and then provide any metadata you want to the Layout field about how to transform it back into its expected shape. The transformation back from 1x700 to 350x2 will need to be done on the other end (where you subscribe to the message), preferably using the metadata provided (since that will be most modular if you change the array size later).

Also, since the Float64MultiArray contains a variable size array, you will need to Manage Array Sizes in Simulink to allow it to handle all 700 elements.

-Cam