slam

Build a Map

Once your robot is started you can enable SLAM mapping as follows:
```
ros2 launch turtlebot3_cartographer cartographer.launch.py
```
Use teleop to drive your robot around the room to create a map. Once you are satisfied with your map, you can save it user the map_saver_cli node:
```
ros2 run nav2_map_server map_saver_cli -f ~/engeo1203
```
You’ll need to edit the resulting engeo1203.yaml file to change the occupied_thresh and free_thresh values to .6 and .18 respectively.
Upload a copy of your finished map to Canvas. Make sure to upload both the .yaml and the .pgm file. Only upload one copy per group.

Clone the following repository into your workspace. This is the starter code for PA2:

https://github.com/JMU-ROBOTICS-VIVA/particle_filter

Build and source this package.
Once this package is installed, you should be able to test the starter code by executing:
```
ros2 launch particle_filter amcl.launch.py use_sim_time:=false map:=$HOME/engeo1203.yaml
```
You should be able to set the initial pose, but the particle filter won’t update, since that code isn’t written yet.
You can test the standard Nav2 particle filter implementation as follows:
```
ros2 launch particle_filter nav2_amcl.launch.py  use_sim_time:=false map:=$HOME/engeo1203.yaml
```
Once this is running, you should be able to set your initial pose and then the robot should be localized correctly as you drive it using teleop.
Try modifying some of the settings in particle_filter/config/default_tb.yaml to see how they impact the behavior of the particle filter. The parameters are documented here:

https://navigation.ros.org/configuration/packages/configuring-amcl.html

You’ll need to rebuild the package to test your changes.

You can launch the full navigation stack, including localization and path planning, as follows. Make sure to shut down any localization nodes you may already have running.
```
ros2 launch turtlebot3_navigation2 navigation2.launch.py map:=$HOME/engeo1203.yaml use_sim_time:=false
```
At this point you should be able to control your robot by selecting navigation goals.