Dual Arm control

[mcaniot]

Hi,
I'm using curobo with a dual arm configuration but i wonder how to manage to give goal on a specific end effector. For now, I m using the plan_single function. The only solution I found for controlling the other end effector is to provide the current position as goal to the end effector and place inside the link_poses the goal I want for the other end effector. It kinda work but i see some differences between controlling the left or the right gripper. Like it is not the same position error on the same, mirror, goal. Do you know if there are another solution ?

[balakumar-s]

If you want to move only one arm at a time, it's better to lock joints of the other arm when planning and switch locks to plan for the second arm.

[mcaniot]

meaning I need to have multiple configs files and cant have one for all my motion ? I cant change the end effector goal on the fly ?

[mcaniot]

Is it in the pipeline to be able to send dual goal instead of one ?

[peter-mitrano-bg]

This is also something I'm interested in. Specifically, I'd like to be able to define pose goals for both arms, and plan for all the joints simultaneously. It doesn't seem like one could do this without modifying core curobo functionality at the moment.

[balakumar-s]

You can send targets for multiple end-effectors. See this for an example: https://curobo.org/get_started/2b_isaacsim_examples.html#multi-arm-reacher

[peter-mitrano-bg]

Ah yes I should have been able to find that. That said, this API is a bit confusing. It seems to take the two goals in with different arguments in different formats (Pose, dict of Pose). I would have expected there to be a different goal type/function, rather than an additional optional argument where one has to be sure to only specify the goals for links that are not the "default" ee_link. Even having a "default" does not make sense for some robots, which the left/right sides are equally valid and you should always need to specify at planning time which should be used. Just my thoughts. Thanks for the quick response!

[peter-mitrano-bg]

One follow question I have is -- how do I specify constraints in this case? I modified my constrained planning example to add link_poses={'other_arm': otherPose} and it only worked if I disabled my constraints (e.g. plan_config.pose_cost_metric = None). Thanks!

[balakumar-s]

Constraints have currently been integrated only for the main ee_link. While constraints would work for additional links, we haven't setup the API.

Regarding API choice on default ee_link and link_poses, link_poses was added much later in the project. I do agree it can be confusing. Ideally, we want to have a separate MultiLinkMotionGen class which should handle pose reaching for multiple links instead of overriding standard MotionGen. Currently, Multi-arm/Multi-link is an experimental feature and we will definitely revisit API choice once sufficient users find it useful.

[yunfanjiang]

Constraints have currently been integrated only for the main ee_link. While constraints would work for additional links, we haven't setup the API.

Would like to follow up on this since I want my second arm to just reach partial poses. Do you have any estimation when this feature will be added? Or could you please suggest how to modify by myself? Thanks.

[DJT777]

I would also like to express my interest in more functionality for multi arm planning

[Alice-ly]

Hi, I want to follow this feature's progress as well, and I have figured out controlling two arms in one xrdf, but have not got valid solution on controlling two arms respectively due to different groups.