Fix gripper mimic joint control (#8)

* Fix gripper mimic joint control * Add dummy joint to prevent Joint not found error [move_group-3] [ERROR] [1692102600.709104192] [moveit_robot_model.robot_model]: Joint 'crane_x7_gripper_finger_b_joint_mimic' not found in model 'crane_x7' See ros-controls/gazebo_ros2_control#173
rt-net · Aug 24, 2023 · e810a76 · e810a76
1 parent 73cd53f
commit e810a76
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Showing 4 changed files with 21 additions and 2 deletions.
diff --git a/urdf/crane_x7.gazebo_ros2_control.xacro b/urdf/crane_x7.gazebo_ros2_control.xacro
@@ -11,6 +11,7 @@
             name_joint_6
             name_joint_7
             name_joint_gripper_finger_a
+            name_joint_gripper_finger_b
             joint_1_lower_limit
             joint_1_upper_limit
             joint_2_lower_limit
@@ -113,7 +114,15 @@
         <state_interface name="velocity"/>
         <state_interface name="effort"/>
       </joint>
+    <joint name="${name_joint_gripper_finger_b}">
+      <param name="mimic">${name_joint_gripper_finger_a}</param>
+      <param name="multiplier">1</param>
+      <command_interface name="position"/>
+      <state_interface name="position"/>
+      <state_interface name="velocity"/>
+      <state_interface name="effort"/>
+    </joint>
 
     </ros2_control>
   </xacro:macro>
-</robot>
+</robot>
diff --git a/urdf/crane_x7.ros2_control.xacro b/urdf/crane_x7.ros2_control.xacro
@@ -134,4 +134,4 @@
 
     </ros2_control>
   </xacro:macro>
-</robot>
+</robot>
diff --git a/urdf/crane_x7.urdf.xacro b/urdf/crane_x7.urdf.xacro
@@ -256,6 +256,7 @@
       name_joint_6="${NAME_JOINT_6}"
       name_joint_7="${NAME_JOINT_7}"
       name_joint_gripper_finger_a="${NAME_JOINT_GRIPPER_FINGER_A}"
+      name_joint_gripper_finger_b="${NAME_JOINT_GRIPPER_FINGER_B}"
       joint_1_lower_limit="${JOINT_1_LOWER_LIMIT}"
       joint_1_upper_limit="${JOINT_1_UPPER_LIMIT}"
       joint_2_lower_limit="${JOINT_2_LOWER_LIMIT}"

diff --git a/urdf/crane_x7_wide_two_finger_gripper.xacro b/urdf/crane_x7_wide_two_finger_gripper.xacro
@@ -78,6 +78,15 @@
       </inertial>
     </link>
 
+    <!--Dummy joint/link to prevent error with mimic joint
+    See https://github.com/ros-controls/gazebo_ros2_control/issues/173
+    -->
+    <joint name="${name_joint_gripper_finger_b}_mimic" type="fixed">
+      <parent link="world" />
+      <child link="dummy_mimic_fix" />
+    </joint>
+    <link name="dummy_mimic_fix"/>
+
     <joint name="${name_joint_gripper_finger_b}" type="revolute">
       <origin xyz="0.012 0.0 0.024" rpy="0 0 0"/>
       <axis xyz="0 1 0"/>