HoloLens and Android compatibility about unity-robotics-hub

[ANG0-0GNA]

Hi!

I tried to apply the tutorial on an Android smartphone and a HoloLens 2.. both builds show the same strange behavior, that the robot arm is randomly jumping. Any solution for that? HoloLens 2 seems to connect to the ROS node (I get the request in the ROS terminal), but with Android this does not work.

Thank you!

Hi, Dietmar @siegeledietmar , could you please show more details about how to apply this tutorial on hololens 2? I plan to build this tutorial ROS–Unity Integration: Publisher . But after click the build button on unity, there are many error shown below:
Assets\RosMessages\RoboticsDemo\msg\PosRot.cs(6,7): error CS0246: The type or namespace name 'RosMessageGeneration' could not be found (are you missing a using directive or an assembly reference?) Assets\RosMessages\RoboticsDemo\msg\UnityColor.cs(6,7): error CS0246: The type or namespace name 'RosMessageGeneration' could not be found (are you missing a using directive or an assembly reference?) Assets\RosMessages\RoboticsDemo\msg\UnityColor.cs(10,31): error CS0246: The type or namespace name 'Message' could not be found (are you missing a using directive or an assembly reference?) Assets\Scripts\RosPublisherExample.cs(10,5): error CS0246: The type or namespace name 'ROSConnection' could not be found (are you missing a using directive or an assembly reference?) Assets\RosMessages\RoboticsDemo\msg\PosRot.cs(43,38): error CS0115: 'PosRot.SerializationStatements()': no suitable method found to override .... .... ....
In Ros Sharp UWP version, I find these are integrated in some plugins, such as RosBridgeClientUWP.dll, etc. I don't know how it works in this project on hololens 2. So could you show the details about how to apply this tutorial on hololens 2? Thank you very much!

[sarah-gibson]

Hi @siegeledietmar,

Are you running the Unity build on Android and HoloLens? Or the ROS side? Or both?

Thanks,
Sarah

[siegeledietmar]

I am running the Unity build on Android and HoloLens 2. The ROS side is running as in the tutorial. When I run it in the Unity Editor it works perfect, when I compile the same Scene, it shows this strange behaviour. I use the XRSDK.

[siegeledietmar]

To be more specific, it happens to me for the Pick and Place tutorial.

[peifeng-unity]

Hi @siegeledietmar,

Thank you for the feedback. We are looking into the issue. In the meantime, may I confirm a couple of things with you:

• Does the "random jumping" issue happen in Part 1 of the Pick and Place tutorial or the Part 3?
• You've mentioned an issue that the Unity build cannot communicate with the ROS nodes properly when running on Android. Does it happen in Pick and Place tutorial too?

Thanks,
Peifeng

[siegeledietmar]

• The issue (for me it seems that the damping and stiffness effects this) can be obtained in Part 1 and 3. It does not appear when running in the Play mode.
• The communication to ROS under Android is not working in the Pick and Place tutorial. In the ROS–Unity Integration tutorial it works fine.

[siegeledietmar]

The communication problem with Android was my fault, that is working fine now, sorry about that..
The misbehavior of the robot arm exists still one HoloLens 2 and Android.

[peifeng-unity]

Get you. We are trying to reproduce the issue. Would you mind to share a gif or a short video about what the "random jumping" looks like? It will be very helpful for us to identify the root cause. Thanks!

[siegeledietmar]

I found in the meantime a simple fix:
Stiffness and Damping values are only set in the Controller script. If I add these values to the X Drive in all Articulation Body it works also as intended on HoloLens and Android.

[peifeng-unity]

Thank you, @siegeledietmar for the feedback. It is great that you have found a workaround.

The stiffness and damping values set in the Controller were supposed to be set to each of the articulation bodies in Start() of the Play, and there was a bug in the URDF-Importer before that didn't configure the damping values. The bug has been fixed now in this PR and the Controller.cs.

[peifeng-unity]

I am going to close this issue since the bug is fixed. Please feel free to reopen it if there are more questions or comments. Thank you!