Practice 2：UOA Robotics Lab Map Building + Navigation

1. 啟動地圖

ros2 launch stage_ros2 stage.launch.py \
world:=/usr/local/share/stage/worlds/uoa_robotics_lab \
enforce_prefixes:=false

2. 檢查 topic

ros2 topic list | grep scan
ros2 topic list | grep cmd_vel
ros2 topic list | grep odom

通常可能會看到：

/robot_0/base_scan
/robot_0/cmd_vel
/robot_0/odom

3. throttle scan

ros2 run topic_tools throttle messages /robot_0/base_scan 10.0 /robot_0/base_scan_throttle

4. SLAM Toolbox 參數

把 mapper_params_stage.yaml 改成：

slam_toolbox:
  ros__parameters:
    use_sim_time: true
    scan_topic: /robot_0/base_scan_throttle
    map_frame: map
    odom_frame: robot_0/odom
    base_frame: robot_0/base_link
    tf_buffer_duration: 30.0

5. 啟動 SLAM

ros2 launch slam_toolbox online_async_launch.py \
  slam_params_file:=/home/lee/nav_class_ws/config/mapper_params_stage.yaml

6. teleop 開車建圖

ros2 run teleop_twist_keyboard teleop_twist_keyboard \
  --ros-args -r cmd_vel:=/robot_0/cmd_vel

建議路線：

1. 起點原地旋轉 360 度
2. 沿著走道慢慢前進
3. 每個房間或轉角都停下來旋轉
4. 回到起點附近做 loop closure
5. 再儲存地圖

7. 儲存地圖

mkdir -p ~/nav_class_assets/maps
ros2 run nav2_map_server map_saver_cli \
  -f ~/nav_class_assets/maps/uoa_lab_map

產生：

uoa_lab_map.yaml
uoa_lab_map.pgm

8. Navigation 使用新地圖

ros2 launch nav2_bringup bringup_launch.py \
  use_sim_time:=true \
  map:=/home/lee/nav_class_assets/maps/uoa_lab_map.yaml \
  params_file:=/home/lee/nav_class_assets/nav2/nav2_stage_robot0.yaml

然後 RViz：

1. Fixed Frame = map
2. 2D Pose Estimate 設定初始位置
3. Nav2 Goal 點選目標