Gazebo subscribe block error in Simulink (bus edit)

Hi, all. I have created Gazebo plugin including several message types, such as contacts, pose, link, joint, and etc. using gazebogenmsg to communicate Simulink and Gazebo.

The plugin works appropriately, and I can read forces and torques using the Gazebo subscribe block in Simulink.

However, when I try to read contacts, then there is an error as shown below.

[Error in Simulink]

An error occurred while running the simulation and the simulation was terminated

Caused by:

• For 'Output Port 2' of 'gazeboCosimControl_ys_v3/Gazebo Robot/Gazebo Subscribe con_info_redbox/SourceBlock', the method 'outputImpl' of the System object 'robotics.slgazebo.internal.GazeboSubscribeBlk' returns a bus type whose field Gazebo_SL_Bus_gazebo_msgs_custom_gazebo_msgs_Contacts.contact.wrench.body_1_wrench.force.x size does not match the field Gazebo_SL_Bus_gazebo_msgs_custom_gazebo_msgs_Contacts.contact.wrench.body_1_wrench.force.x size defined in the method 'getOutputDataTypeImpl'.

or,

• For 'Output Port 2' of 'gazeboCosimControl_ys_v3/Gazebo Robot/Gazebo Subscribe con_info_redbox/SourceBlock', the method 'outputImpl' of the System object 'robotics.slgazebo.internal.GazeboSubscribeBlk' returns a bus type whose field Gazebo_SL_Bus_gazebo_msgs_custom_gazebo_msgs_Contacts.contact.position.x size does not match the field Gazebo_SL_Bus_gazebo_msgs_custom_gazebo_msgs_Contacts.contact.position.x size defined in the method 'getOutputDataTypeImpl'.

In this case, the Gazebo_SL_Bus_gazebo_msgs_custom_gazebo_msgs_Contacts.contact.wrench.body_1_wrench.force.x is of variable length. The received message data is excceding dimension limit ( default is 128), so I need to increase dimension limit from Bus Editor.

When I get these errors, I know that I need to customize Bus objects for sumulation using the Bus Editor from https://www.mathworks.com/help/robotics/ug/control-manipulator-robot-with-co-simulation.html.

My question is, how to determine the mode, data type, dimension and dimension mode?

For instance, I would like to read the following topics from Gazebo.

1) collision1: "redBox::link::collision_redbox"

2) collision2: "ground_plane::link::collision"

3) wrench {

body_1_name: "redBox::link::collision_redbox"

body_1_id: 87

body_2_name: "ground_plane::link::collision"

body_2_id: 6

body_1_wrench {

force {

x: -0.0040215821663263434

y: -0.0035342300169850984

z: 0.00612709962277502

}

torque {

x: 8.4268671424788638e-05

y: -6.842890014103444e-05

z: 1.5792249417875155e-05

}

}

Current setting of the bus editor for them,

collision1, 2: Model=built in, Data type=unit8, Dimensions=128, DimensionModel=Variable

Wrench: Model=bus object, Dimensions=1, DimensionsMode=Fixed

Could you let me know how to modify them?

Thank you very much!

Yunsik

[Jagadeesh Konakalla]

Hi Yunsik,

We have a detailed example on how to set variable size arrays in ROS toolbox. Here are the useful links. Can you please follow these examples and topic section.

https://www.mathworks.com/help/ros/ug/work-with-ros-messages-in-simulink.html

https://www.mathworks.com/help/ros/ug/manage-array-sizes-in-simulink-ros.html

Let me know if it does not address your issue.

Thanks,

Jagadeesh K.

Answer 1

[Gaurav Bhosale]

Hi Yunsik,

The solution is provided in the following susequent post.

variable size elemets

read body names

Please refer above posts.

Thanks