Adapt reflexxes to KUKA LBR iiwa R820

[ahundt]

As a step in learning V-Rep I'm trying to adapt the reflexxes demo to run with the KUKA LBR iiwa R820. I've put the model in and copied some of the scripts and configuration from the ABB arm renamed the component strings to match the new kuka strings, added dummy targets, plus added some IK configuration. However, there are several problems.

- The kuka arm model doesn't move, even though it shows a red line of where it should go.
- The ABB arm is still there and I expected it to plan around the kuka so it wouldn't collide
- The planning doesn't seem to plan around the presence of the new kuka arm and the kuka just gets knocked over.

What am I most likely to be missing in the configuration?

The file can be accessed here if you need more details:
https://drive.google.com/file/d/0B9Zw0G ... sp=sharing

Thanks!

[coppelia]

Hello,

can you upload the file again, it seems that it is corrupt (I cannot open it).

Cheers

[ahundt]

I fixed the link and tested it. It should work now.

[coppelia]

You have several problems with your scene:

• since you want to control the robot via IK, you need to set all its joints in IK mode, and enable their hybrid operation.
• because non of your joints were in IK mode, the IK element was automatically disabled (since not valid). Enable it again.
• The initial position and orientation of the dummy tip and dummy target (of the IK task) are not the same: the robot will jump and will not be able to follow the target. Make sure the tip dummy has the exact same position and orientation as its linked target.
• What can also be a cause of instability: the initial configuration of the robot is singular (in that stretched configuration). You could change the initial configuration of the robot.
• The base of your robot is not static: the robot might fall.

Cheers

[ahundt]

Thank you for the feedback, I was able to figure out all of those steps and the simulation looks closer to working, but for some reason the suction cup appears to explode off of the arm, causing the simulation to break completely. I think it may be the way I have it attached, but I'm not sure how to set it in the right location with the correct configuration.

Could you possibly explain the issue here?

Thank you very much for your help! It is greatly appreciated.

Here is the new link to the updated simulation:
https://github.com/ahundt/robone/raw/e2 ... e4Demo.ttt

[ahundt]

I've made some more progress, I believe the orientation wasn't lined up properly. It appears to almost work now but the suction cup does not successfully grab the cuboid. All the strings appear to match up in the scripts so I'm not sure what is preventing this last step from working correctly.

Updated simulation file:
https://github.com/ahundt/robone/raw/bb ... e4Demo.ttt

[coppelia]

Ok, you still have several problems in your scene:

• The blocks sometimes collide with the robot body. In that case it is normal that something breaks.
• The object LBR_iiwa_14_R820_link8 should not be part the the dynamic hierarchy. Simply make object suctionPad#0 child of object LBR_iiwa_14_R820_link8_resp.
• Finally, your blocks have a large mass (i.e. 8 Kg) compared to the suctionPadBodyRespondable#0 (i.e. 0.4 Kg). This could also lead to some wobbling. Make sure you have read this page, mainly Design considerations 7.

Cheers

[ahundt]

How do I tell that the block is colliding with the robot body? Since the blocks don't get picked up at the moment I'm not sure what you mean. Also, how to I make the suction cup actually pick up the blocks?

I also don't understand why the change between LBR_iiwa_14_R820_link8 and LBR_iiwa_14_R820_link8_resp should not be part of the dynamic hierarchy. I made the change and the suction cup no longer flies off, I'm just hoping to understand why.

Finally, I didn't change the mass from the original demo, the suction pad in the original demo is 0.4kg so I'm not sure why that is an issue.

Thank you for all your help I'm learning a lot about how to use the software.

[coppelia]

Make sure you upgrade to V-REP 3.2.0. Then it should work.
In V-REP versions before that, if you disable a child script, its children will automatically also be disabled (in your case the child script that handles the vacuum cup). If you stay with the old V-REP version, simply make sure to enable the child scipt attached to object LBR_iiwa_14_R820, and remove its content.

Cheers

[ahundt]

Thanks, updating to 3.2.0 did work.