Allow specifying joint limits in degrees

[gavanderhoorn]

The current implementation only supports specifying joint position and velocity limits in radians.

It should also support degrees.

[gavanderhoorn]

Either the whole UI would need to be switchable between degrees/radians, or a special (spinner) widget would need to be added that provides UI to do this on a per-property basis.

[gavanderhoorn]

@pitschm1: just making sure: from pitschm1/CAD-to-ROS@72e385e7 it seems like you are adding support for USCS units. Is that work meant for the enhancement described in this issue?

[msymmank]

@gavanderhoorn: Yes, I have added a "Units" property to both position and orientation for the user to specify either metric [m, rad], or USCS [in, deg]. It does the conversion between them. I am working on an issue where it sometimes fails to save the conversion when the file is closed and reopened.

[gavanderhoorn]

Ok, thanks for the clarification.

Note that ROS doesn't support anything but SI units, and that this ticket only asked for the ability to specify things like joint angles and limits in degrees (while still saving radians in the resulting urdf), not switch the entire application to USCS.

I'm not saying that is something that we couldn't consider a useful functionality, but it would have the include a mode where supporting just the degree->radian conversion (and leaving everything else SI in the UI) is possible.

Note that I may have been ambiguous when describing the desired functionality, switching the whole application to USCS didn't occur to me (I'm from 'SI country').

[msymmank]

@gavanderhoorn: It's implemented as a GUI front-end feature. All inputs are converted into meters and radians before it gets to ROS. When the data loads, it is then converted from meters and radians to what the user has specified.

It is also possible to leave everything SI except degrees. The user specifies the unit type separately for position and orientation allowing them to use meters and degrees or inches and radians as they deem appropriate. It seemed that degrees were requested as an option was to make it more intuitive to users, I also added the option to specify inches rather than meters because to some users in the US it would also be more intuitive. It can be removed without any trouble if it's not useful.

[gavanderhoorn]

It can be removed without any trouble if it's not useful.

It sounds like supporting USCS might be nice to have. As long as the primary requirement (being able to specify joint limits and angles in degrees instead of radians) is covered, we can probably merge in the rest as well.

It would be nice to split the addition of the extra functionality from the changes that add the support for degrees though. If I understand you correctly, the USCS work is essentially an extension of that, so it sounds like that would be possible, and it would make reviewing the eventual PR much easier.