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Official URDF and SDF models of the iCub humanoid robot.
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[iCubGazeboV3] Change feet collision meshes to simplified geometry #66

Closed prashanthr05 closed 3 years ago

prashanthr05 commented 3 years ago

I am trying to change the feet meshes to replace it with simplified geometry.

I got the bounding box for the feet from MeshLab as, l_foot_front l_foot_rear r_foot_front r_foot_rear
l_foot_front l_foot_rear r_foot_front_bb r_foot_rear

They all have the same dimensions and are in mm (I believe!).

However, in the URDF there seems to be a scale option for the mesh that scales the mesh's axis-aligned-bounding-box, according to http://wiki.ros.org/urdf/XML/link. There's no further explanation. 

      <geometry>
        <mesh filename="package://iCub/meshes/simmechanics/sim_icub3_l_foot_rear_prt.stl" scale="0.001 0.001 0.001"/>
      </geometry>

I believe the scale is simply a unit conversion from millimeters to meters.

So I made the changes only to the collision part of the feet as

    <collision>
      <origin xyz="0.010700000000000012 -0.06475000000001183 0.9464469999999995" rpy="0 0 -1.5707963267948966"/>
<!--      
      <geometry>
        <mesh filename="package://iCub/meshes/simmechanics/sim_icub3_l_foot_rear_prt.stl" scale="0.001 0.001 0.001"/>
      </geometry>
-->
      <geometry>
        <box size="0.1 0.117 0.010299988"/>
      </geometry>
    </collision>

But looks like, there's something I am missing here, which can be seen as soon as we load the model,

ezgif com-gif-maker

Anyone's got advice/prior experience on this? cc @nunoguedelha @traversaro @S-Dafarra @GiulioRomualdi

S-Dafarra commented 3 years ago

I guess this is what is done on iCub2.5 https://github.com/robotology/icub-models/blob/05e4e60ed08937fd292e34dd81119a0e7d78c7f6/iCub/robots/iCubGazeboV2_5/model.urdf#L527-L532

Can you provide a link to your modifications?

prashanthr05 commented 3 years ago

Can you provide a link to your modifications?

I have it here for the time being.

prashanthr05 commented 3 years ago

Looks like the origin for the collision geometry was modified in https://github.com/robotology/icub-models/blob/05e4e60ed08937fd292e34dd81119a0e7d78c7f6/iCub/robots/iCubGazeboV2_5/model.urdf#L527-L532

I hope this was not done by trial-and-error?

S-Dafarra commented 3 years ago

Can you try to put the robot fixed in the air and visualize the collisions?

traversaro commented 3 years ago

I hope this was not done by trial-and-error?

This is specified in https://github.com/robotology/icub-model-generator/blob/master/simmechanics/CMakeLists.txt#L97 that was added in https://github.com/robotology/icub-model-generator/pull/85 .

traversaro commented 3 years ago

To simplify the debug, I strong suggest to temporary disabled the visual meshes, so you would see just simplified mesh that you add. For the dimension of the box and the placement, I suggest to use as a reference the location of the l_sole frames, as I imagine was done for iCub 2.5 .

prashanthr05 commented 3 years ago

I hope this was not done by trial-and-error?

This is specified in https://github.com/robotology/icub-model-generator/blob/master/simmechanics/CMakeLists.txt#L97 that was added in robotology/icub-model-generator#85 .

I was wondering about the choice and source of the values in

https://github.com/robotology/icub-models/blob/05e4e60ed08937fd292e34dd81119a0e7d78c7f6/iCub/robots/iCubGazeboV2_5/model.urdf#L528

which is different from,

https://github.com/robotology/icub-models/blob/05e4e60ed08937fd292e34dd81119a0e7d78c7f6/iCub/robots/iCubGazeboV2_5/model.urdf#L519

but seems to be the same as,

https://github.com/robotology/icub-model-generator/blob/5f1ccfe8031fa2bbcd341c83fd85a10a93b381bf/simmechanics/CMakeLists.txt#L116

traversaro commented 3 years ago

https://github.com/robotology/icub-models/blob/05e4e60ed08937fd292e34dd81119a0e7d78c7f6/iCub/robots/iCubGazeboV2_5/model.urdf#L528

which is different from,

https://github.com/robotology/icub-models/blob/05e4e60ed08937fd292e34dd81119a0e7d78c7f6/iCub/robots/iCubGazeboV2_5/model.urdf#L519

Why they should be similar? The origin of the box is placed in the center of the box (see http://wiki.ros.org/urdf/XML/link) while the origin of the visual mesh is arbitrary.

prashanthr05 commented 3 years ago

To simplify the debug, I strong suggest to temporary disabled the visual meshes, so you would see just simplified mesh that you add. For the dimension of the box and the placement, I suggest to use as a reference the location of the l_sole frames, as I imagine was done for iCub 2.5 .

I read this only now. Understood.

prashanthr05 commented 3 years ago

With @FabioBergonti, we modified the visual and collision geometries for all the feet links using data from the CAD,

  <link name="r_foot_front">
   ...
    <visual>
      <origin xyz="0.0 0.0 0.003" rpy="0 0 0"/>
      <geometry>
        <box size="0.117 0.100 0.006"/>
      </geometry>
      ...
    </visual>
    <collision>
      <origin xyz="0.0 0.0 0.003" rpy="0 0 0"/>
      <geometry>
        <box size="0.117 0.100 0.006"/>
      </geometry>
    </collision>
  </link>
On loading the model, we see View 1 View 2
Screenshot from 2020-11-06 11-41-11 Screenshot from 2020-11-06 11-52-06

Peek 2020-11-06 11-56

S-Dafarra commented 3 years ago

Great @prashanthr05! From the gif it seems a little tilted. Is it only my impression? You can also try to use the fixed version to look at the feet from below

prashanthr05 commented 3 years ago

Great @prashanthr05! From the gif it seems a little tilted. Is it only my impression? You can also try to use the fixed version to look at the feet from below

It is indeed tilted because of my poor camera skills ;D.

I tried loading the fixed version in vain. It keeps falling to the ground. The SDF format seems to be the same as fixed models in icub-gazebo, while those in icub-gazebo remain fixed, instead those in icub-models don't. Is it just me who is facing this?

traversaro commented 3 years ago

This seems to be related to the base_link / root_link change .

prashanthr05 commented 3 years ago

This seems to be related to the base_link / root_link change .

Wow, such a memory! I am going to check this. Thanks, @traversaro !

prashanthr05 commented 3 years ago

I tried loading the fixed version in vain. It keeps falling to the ground. The SDF format seems to be the same as fixed models in icub-gazebo, while those in icub-gazebo remain fixed, instead those in icub-models don't. Is it just me who is facing this?

This seems to be related to the base_link / root_link change .

I confirm. Changing the fixed joint child from base_link to root_link, makes it work.

    <joint name="fixed_base" type="fixed">
      <parent>world</parent>
      <child>iCub::root_link</child>
    </joint>
prashanthr05 commented 3 years ago
With the fixed model, View 1 View 2 View 3
Screenshot from 2020-11-06 12-59-49 Screenshot from 2020-11-06 12-59-19 Screenshot from 2020-11-06 12-58-27
prashanthr05 commented 3 years ago

I will open relevant PRs in the icub-model-generator.

prashanthr05 commented 3 years ago

I tried loading the fixed version in vain. It keeps falling to the ground. The SDF format seems to be the same as fixed models in icub-gazebo, while those in icub-gazebo remain fixed, instead those in icub-models don't. Is it just me who is facing this?

This seems to be related to the base_link / root_link change .

I confirm. Changing the fixed joint child from base_link to root_link, makes it work.

    <joint name="fixed_base" type="fixed">
      <parent>world</parent>
      <child>iCub::root_link</child>
    </joint>

This has already been done in https://github.com/robotology/icub-models/pull/59.

S-Dafarra commented 3 years ago

Indeed, also to me the old fixed iCubV3 falls down, but the iCubGazeboV3 does not.

prashanthr05 commented 3 years ago

To introduce the changes of assigned collision geometries from here to the URDF model through icub-model-generator, I will list the steps I will follow, please correct me wherever applicable

S-Dafarra commented 3 years ago

To introduce the changes of assigned collision geometries from here to the URDF model through icub-model-generator, I will list the steps I will follow, please correct me wherever applicable

@pattacini @Nicogene what do you think?

prashanthr05 commented 3 years ago

Tested locally with changes made in https://github.com/prashanthr05/icub-model-generator/commit/d151943dad14ea87a9e644184a86d2dcce1828fa and https://github.com/prashanthr05/icub-model-generator/commit/8d08a83445af8216f912d49bdebb404e8aa32b9a

The diff between the files with the introduced option and without (changes for all the foot_rear/front links),

<       <origin xyz="0.0 0.0 0.003" rpy="0.0 0.0 0.0"/>
---
>       <origin xyz="0.010700000000000012 -0.06475000000001183 0.9464469999999995" rpy="0 0 -1.57079632679"/>
250c250
<         <box size="0.117 0.1 0.006"/>
---
>         <mesh filename="package://iCub/meshes/simmechanics/sim_icub3_l_foot_rear_prt.stl" scale="0.001 0.001 0.001"/>
283c283
<       <origin xyz="0.0 0.0 0.003" rpy="0.0 0.0 0.0"/>
---
>       <origin xyz="-0.10854999999999998 -0.06475000000001183 0.9464469999999995" rpy="0 0 -1.57079632679"/>
285c285
<         <box size="0.117 0.1 0.006"/>
---
>         <mesh filename="package://iCub/meshes/simmechanics/sim_icub3_l_foot_front_prt.stl" scale="0.001 0.001 0.001"/>
1202c1202
<       <origin xyz="0.0 0.0 0.003" rpy="0.0 0.0 0.0"/>
---
>       <origin xyz="-0.10850000000000011 0.06484999999993908 0.9464470000000105" rpy="0 0 -1.57079632679"/>
1204c1204
<         <box size="0.117 0.1 0.006"/>
---
>         <mesh filename="package://iCub/meshes/simmechanics/sim_icub3_r_foot_front_prt.stl" scale="0.001 0.001 0.001"/>
1230c1230
<       <origin xyz="0.0 0.0 0.003" rpy="0.0 0.0 0.0"/>
---
>       <origin xyz="0.010749999999999881 0.0648499999999391 0.9464470000000105" rpy="0 0 -1.57079632679"/>
1232c1232
<         <box size="0.117 0.1 0.006"/>
---
>         <mesh filename="package://iCub/meshes/simmechanics/sim_icub3_r_foot_rear_prt.stl" scale="0.001 0.001 0.001"/>

P.S. I had to test by disabling GENERATE_DH_MODELS and tests. See https://github.com/robotology/icub-model-generator/issues/161 and https://github.com/robotology/icub-model-generator/pull/159

cc @traversaro

traversaro commented 3 years ago

P.S. I had to test by disabling GENERATE_DH_MODELS and tests. See robotology/icub-model-generator#161 and robotology/icub-model-generator#159

Yes, that is expected.

prashanthr05 commented 3 years ago

Given the merge of https://github.com/robotology/icub-model-generator/pull/165, shall we close this issue?

traversaro commented 3 years ago

Ok!