message: CHANGE: Move panda_link8_sc -> panda_link7_sc
  The capsule at link8 covers the Pilot which is attached to link7. Though rigidly
  connected to link7, link8 is more a "virtual" link without geometry indicating
  the flange of the robot. That's why it makes more sense to also have the
  collision capsule attached to link7_sc.
diff: <xacro:link_detailed_coarse name="link7" rpy="0 0 ${pi/4}">
  <self_collision_geometries>
  <xacro:collision_capsule xyz="0 0 0.01" direction="z" radius="${0.04+safety_distance}" length="0.14" />
  + <xacro:collision_capsule xyz="0.06 0 0.082" direction="x" radius="${0.03+safety_distance}" length="0.01" />
  </self_collision_geometries>
  </xacro:link_detailed_coarse>
  </joint>
  <link name="${arm_id}_link8"/>
  - <link name="${arm_id}_link8_sc">
  - <collision>
  - <origin xyz="0.0424 0.0424 -0.0250" rpy="${pi} ${pi/2} ${pi/2}"/>
  - <geometry>
  - <cylinder radius="${0.03+safety_distance}" length="0.01" />
  - </geometry>
  - </collision>
  - <collision>
  - <origin xyz="0.0424 0.0424 -0.02" rpy="0 0 0"/>
  - <geometry>
  - <sphere radius="${0.03+safety_distance}" />
  - </geometry>
  - </collision>
  - <collision>
  - <origin xyz="0.0424 0.0424 -0.03" rpy="0 0 0"/>
  - <geometry>
  - <sphere radius="${0.03+safety_distance}" />
  - </geometry>
  - </collision>
  - </link>
  + <link name="${arm_id}_link8_sc"/>
  +
  <joint name="${arm_id}_link8_sc_joint" type="fixed">
  <parent link="${arm_id}_link8" />
  <child link="${arm_id}_link8_sc" />
  