Gripper not responding correctly

[nzlz]

Bug report

Required Info:

Ubuntu 18, ROS2 Crystal

Bug
The gripper is not working correctly anymore, not sure if the new URDF is causing it or the mara joint plugin. If i spawn the gripper alone the fingers move as expected, but attached to the mara if needs a much higher goal_linearposition than the maximum 0.8 limit.

You can reproduce it using:

ros2 service call /hrim_actuation_gripper_000000000004/goal hrim_actuator_gripper_srvs/ControlFinger "{goal_linearposition: 0.8}"

[nzlz]

Confirmed that is is a MARA URDF issue. The previous URDF (updating the plugins to the new), of which we have a backup in the ai branch, works fine.

[YueErro]

Yep, there is an issue with the gripper in the current orientation. If you unflip it, it works fine (end_effector_adapter_to_robotiq joint).

If you also flip it in robotiq_modularripper to spaw it alone, it also stops working properly.

Not sure if it is urdf issue, i do not see anything weird. Maybe the inertia values?

hros_robotiq_adapter is also 1.57 flipped in yaw if we compare it with the real robot, anyhow, this does not affect the open/close action of the gripper

[nzlz]

Can confirm what @YueErro said, the following change fixes the issue:

  <joint name="end_effector_adapter_to_robotiq" type="fixed">
-    <origin rpy="0 0 1.57" xyz=" 0 0 0.0"/>
+    <origin rpy="0 0 0" xyz=" 0 0 0.0"/>

[YueErro]

I can not understand the logic behind this which make the gripper stop closing.

The gripper should work fine in any orientation. In our particular case, to match with the real robot, we need to flip it as it is right now, 1.57 in yaw.

[ahcorde]

try to rotate only the visual and the collision

[YueErro]

Already tried it. Did not work.

[nzlz]

Will discuss internally.