Add the option for the external force orientation to be reperesented in the link frame #463

HosameldinMohamed · 2020-01-28T13:30:48Z

Proposed feature to add:

To have an option to specify the wrenches orientations in the link frame.
The user interface can be similar to what had been done in Update external wrench plugin with mutiple wrenches and improve rpc responses #418

Where the user can write a command:

orient_local

And the mode will change to "orient_local" where the applied forces will have the orientation of the link frame. Moreover, the user will specify the force components w.r.t the link frame.

Writing the command:

orient_global

Will switch to the already implemented settings.

The default setting is orient_global.

Related issue: #462

Other modification:

Before: If the user writes any 1-word command other than single, the mode is switched to multiple wrenches mode (see #418).

After: If the user commands any 1-word command other than single, multiple, orient_global, orient_local, they will receive an error and a message:

ERROR: Incorrect command format. Insert [help] to know the correct command format

…entationWrench()`

plugins/externalwrench/src/ApplyExternalWrench.cc

traversaro

Preliminary comments, I did not reviewed all of the PR.

Can you update the CHANGELOG.md file? Thanks!

HosameldinMohamed · 2020-01-28T15:24:56Z

Can you update the CHANGELOG.md file? Thanks!

Done in 6a7134d and a conflict in CHANGELOG.md was resolved.

traversaro · 2020-01-28T18:31:34Z

Thanks @HosameldinMohamed ! I will probably need a bit of help with the math, either @prashanthr05 or @Yeshasvitvs can help me on that? Thanks!

CHANGELOG.md

prashanthr05 · 2020-01-29T15:31:15Z

plugins/externalwrench/src/ApplyExternalWrench.cc

            this->m_reply.addString ( "Insert [single] or [multiple] to change the operation mode" );
+            this->m_reply.addString ( "The default frame orientation is the one of the base/root frame ([orient_global])" );


Is it one of the base/root frame or the world frame? The words base/root and global seem to not to go along well.

you're right it's confusing. However the phrase "The default frame orientation is the one of the base/root frame" was written before and I didn't want to change it even though the applied force's frame seems to have the orientation of the global one.

Check out this little demo where I apply forces in X,Y and Z directions in global_orient mode:

prashanthr05 · 2020-02-03T12:18:19Z

plugins/externalwrench/src/ExternalWrench.cc

@@ -147,7 +147,7 @@ void ExternalWrench::applyWrench()
        ignition::math::Vector3d newY = newZ.Cross (newX);
        ignition::math::Matrix4d rotation = ignition::math::Matrix4d (newX[0],newY[0],newZ[0],0,newX[1],newY[1],newZ[1],0,newX[2],newY[2],newZ[2],0, 0, 0, 0, 1);
        ignition::math::Quaterniond forceOrientation = rotation.Rotation();
-        ignition::math::Pose3d linkCoGPose (linkCoGPos - rotation*ignition::math::Vector3d ( 0,0,.15 ), forceOrientation);
+        ignition::math::Pose3d W_p_F (linkCoGPos - rotation*ignition::math::Vector3d ( 0,0,.15 ), forceOrientation);


A pose can be identified with H or T. Here W_p_F is confusing as to a position and not a Pose.

And why the variable naming W_p_F ? Anyways the force are applied to the CoG of the link right? Only the visual is offset by these magic numbers?

A pose can be identified with H or T. Here W_p_F is confusing as to a position and not a Pose.

Right, in the next commit I have changed the abbreviations to be more clear. Considering only Transformation T, Rotation R, or Position P.

And why the variable naming W_p_F ? Anyways the force are applied to the CoG of the link right? Only the visual is offset by these magic numbers?

I have changed the name of the variable to more clear and explicit name.

plugins/externalwrench/src/ExternalWrench.cc

plugins/externalwrench/src/ApplyExternalWrench.cc

plugins/externalwrench/src/ExternalWrench.cc

prashanthr05 · 2020-02-08T17:28:54Z

plugins/externalwrench/src/ExternalWrench.cc

+
+        math::Vector3d linkCoGPos = link->WorldCoGPose().Pos(); // Get link's COG position where wrench will be applied
+        math::Vector3d newZ = force.Normalized(); // normalized force. I want the z axis of the cylinder's reference frame to coincide with my force vector
+        math::Vector3d newX = newZ.Cross (math::Vector3d::UnitZ);


Should we consider here the UnitZ of the Gazebo world ? or the UnitZ of the link?

I think the current setting is OK (in Gazebo world). Since UnitZ is used to construct the transformation from the applied force frame to the Link CoG frame (Lg_T_F), which then is multiplied to the transformation between the world frame and the Link CoG frame:

ignition::math::Matrix4d W_T_F = W_T_Lg*Lg_T_F;

In this line for example.

CLAassistant · 2020-04-20T15:51:01Z

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

traversaro · 2020-04-20T16:00:47Z

Hi @HosameldinMohamed , what is the status of this PR?

HosameldinMohamed · 2020-04-20T17:10:47Z

Hi @HosameldinMohamed , what is the status of this PR?

Hi @traversaro , it's pending me addressing to some of @prashanthr05 comments and a discussion we had. I'll do it very soon.

traversaro · 2021-06-26T09:49:02Z

@HosameldinMohamed @prashanthr05 if we do not have plans to continue on this PR in the short term, we can always close it and re-open it again once we want to work on it again.

HosameldinMohamed · 2021-06-28T08:22:51Z

@HosameldinMohamed @prashanthr05 if we do not have plans to continue on this PR in the short term, we can always close it and re-open it again once we want to work on it again.

Hi @traversaro Right. I don't think I will be able to work on this PR in the short term. So I close it for now.

HosameldinMohamed added 3 commits January 27, 2020 12:14

Add the option of the frame to represent the applied wrench

b2fad6c

Add the functions applyGlobalOrientationWrench() and `applyLocalOri…

b674a93

…entationWrench()`

Make some modifications in the comments

742b2a5

HosameldinMohamed requested review from yeshasvitirupachuri, traversaro and prashanthr05 January 28, 2020 13:31

HosameldinMohamed mentioned this pull request Jan 28, 2020

Add in the externalwrench plugin the option to specify the orientation frame "local" #462

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Address comments: modify the "help" response + CHANGELOG.md file

6a7134d

Merge branch 'devel' into feature/addOrientOption

bedcdf5

Some minor changes

0709086

traversaro reviewed Jan 29, 2020

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prashanthr05 requested changes Feb 8, 2020

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HosameldinMohamed added 2 commits February 16, 2020 23:25

Address comments - organize the source code

c60fd0c

some minor modifications

c00ff7e

HosameldinMohamed closed this Jun 28, 2021

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Add the option for the external force orientation to be reperesented in the link frame #463

Add the option for the external force orientation to be reperesented in the link frame #463

HosameldinMohamed commented Jan 28, 2020 •

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prashanthr05 Jan 29, 2020

HosameldinMohamed Feb 16, 2020

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prashanthr05 Feb 8, 2020

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prashanthr05 Feb 8, 2020

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CLAassistant commented Apr 20, 2020

traversaro commented Apr 20, 2020

HosameldinMohamed commented Apr 20, 2020

traversaro commented Jun 26, 2021

HosameldinMohamed commented Jun 28, 2021

		this->m_reply.addString ( "Insert [single] or [multiple] to change the operation mode" );
		this->m_reply.addString ( "The default frame orientation is the one of the base/root frame ([orient_global])" );

Add the option for the external force orientation to be reperesented in the link frame #463

Add the option for the external force orientation to be reperesented in the link frame #463

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HosameldinMohamed commented Jan 28, 2020 • edited Loading

Proposed feature to add:

Other modification:

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HosameldinMohamed commented Jan 28, 2020 •

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