Mimic joints result in "The complete state of the robot is not yet known" errors from environment monitor

[mpowelson]

[Levi-Armstrong]

Ah, the mimic joints have not been implemented.

[mpowelson]

@Levi-Armstrong Would you mind commenting on what you think would be involved to fix this? Would this be a good first issue (e.g. for World ROS-I day 2021)?

[Levi-Armstrong]

I was thinking about leveraging this library to create a simple joint which wraps this. I think we would just copy in the .h and .c into tesseract_urdf.

[Levi-Armstrong]

Another option is ExprTx and we could just copy the .hpp file.

[dave992]

Currently also running into this issue. Would be willing to contribute here if I can help.

I did find a lot of references to mimic joints in the code already, but I am not completely sure what changes are still needed. From what I observed:

• isPassiveOrMimicDOF() will need to be completed in order to prevent the warning
• The mimic joint needs to be changed to not be returned as a "active" joint, e.g. via tesseract_environment::Environment::getActiveJointNames()
• I assume the value for the mimic joint needs to be calculated and written to the environement somewhere in the environment monitor.

[Levi-Armstrong]

I will need to spend some time looking into how best to support mimic joints

[rjoomen]

See #267 for tesseract_ros.