fix: align MKMini lidar and world obstacles

src/nav2_turtlebot_simulator/launch/simulator.launch.py

@@ -220,6 +220,24 @@ def create_mkmini_world(gazebo_dir):
         except ValueError:
             continue
 
+    # The MKMini lidar is centered at 0.52 m. Raise the original 0.5 m white
+    # pillars so they remain observable obstacles instead of falling below the
+    # scan plane.
+    for element in (*model.findall('.//collision'), *model.findall('.//visual')):
+        cylinder = element.find('./geometry/cylinder')
+        if cylinder is None:
+            continue
+        if cylinder.findtext('radius') != '0.15' or cylinder.findtext('length') != '0.5':
+            continue
+        cylinder.find('length').text = '0.8'
+        pose = element.find('pose')
+        if pose is None:
+            continue
+        values = pose.text.split()
+        if len(values) == 6:
+            values[2] = '0.4'
+            pose.text = ' '.join(values)
+
     model_tree.write(
         os.path.join(model_dir, 'model.sdf'),
         encoding='utf-8',