diff --git a/chapt7/chapt7_ws/README.md b/chapt7/chapt7_ws/README.md
index ec1ddee..d220f6e 100644
--- a/chapt7/chapt7_ws/README.md
+++ b/chapt7/chapt7_ws/README.md
@@ -61,7 +61,7 @@ colcon build
 
 ```
 source install/setup.bash
-ros2 launch fishbot_description gazebo.launch.py
+ros2 launch fishbot_description gazebo_sim.launch.py
 ```
 
 运行导航
diff --git a/chapt7/chapt7_ws/src/fishbot_description/config/fishbot_ros2_controller.yaml b/chapt7/chapt7_ws/src/fishbot_description/config/fishbot_ros2_controller.yaml
index 8a60aeb..5bcf6cc 100644
--- a/chapt7/chapt7_ws/src/fishbot_description/config/fishbot_ros2_controller.yaml
+++ b/chapt7/chapt7_ws/src/fishbot_description/config/fishbot_ros2_controller.yaml
@@ -29,7 +29,7 @@ fishbot_diff_drive_controller:
     left_wheel_names: ["left_wheel_joint"]
     right_wheel_names: ["right_wheel_joint"]
 
-    wheel_separation: 0.17
+    wheel_separation: 0.20
     #wheels_per_side: 1  # actually 2, but both are controlled by 1 signal
     wheel_radius: 0.032
 
@@ -40,8 +40,8 @@ fishbot_diff_drive_controller:
     publish_rate: 50.0
     odom_frame_id: odom
     base_frame_id: base_footprint
-    pose_covariance_diagonal : [0.001, 0.001, 0.0, 0.0, 0.0, 0.01]
-    twist_covariance_diagonal: [0.001, 0.0, 0.0, 0.0, 0.0, 0.01]
+    pose_covariance_diagonal : [0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
+    twist_covariance_diagonal: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
 
     open_loop: true
     enable_odom_tf: true
diff --git a/chapt7/chapt7_ws/src/fishbot_description/urdf/fishbot/plugins/gazebo_sensor_plugin.xacro b/chapt7/chapt7_ws/src/fishbot_description/urdf/fishbot/plugins/gazebo_sensor_plugin.xacro
index c69cbb4..c45ad66 100644
--- a/chapt7/chapt7_ws/src/fishbot_description/urdf/fishbot/plugins/gazebo_sensor_plugin.xacro
+++ b/chapt7/chapt7_ws/src/fishbot_description/urdf/fishbot/plugins/gazebo_sensor_plugin.xacro
@@ -6,14 +6,14 @@
                 <plugin name="laserscan" filename="libgazebo_ros_ray_sensor.so">
                     <ros>
                         <namespace>/</namespace>
-                        <remapping>~/out:=scan</remapping>
+                        <remapping>~/out:=scan1</remapping>
                     </ros>
                     <output_type>sensor_msgs/LaserScan</output_type>
                     <frame_name>laser_link</frame_name>
                 </plugin>
                 <always_on>true</always_on>
-                <visualize>true</visualize>
-                <update_rate>5</update_rate>
+                <visualize>false</visualize>
+                <update_rate>10</update_rate>
                 <pose>0 0 0 0 0 0</pose>
 								<!-- 激光传感器配置 -->
                 <ray>
diff --git a/chapt7/chapt7_ws/src/navigation2 b/chapt7/chapt7_ws/src/navigation2
new file mode 160000
index 0000000..150dd6b
--- /dev/null
+++ b/chapt7/chapt7_ws/src/navigation2
@@ -0,0 +1 @@
+Subproject commit 150dd6beb50aee502ada8935cee23d7160a40f57