Mapping and Navigation for Simulation

Mapping

Run simulation related nodes

Run roscore
```
roscore
```
Launch the robot (In another terminal)
```
roslaunch mir_bringup_sim robot.launch
```
Run gazebo simulator (In another terminal)
```
rosrun gazebo_ros gzclient
```
Run rviz (In another terminal)
```
rosrun rviz rviz
```
Note

To setup the RViz, please go to the bottom of this page.

Generate map

Run 2D SLAM (In another terminal)
```
roslaunch mir_2dslam 2dslam.launch
```
Now there should be robot in an empty map in RViz.
Move the robot around the map. (In another terminal)
```
roslaunch mir_teleop teleop_keyboard.launch
```
WSAD keys set the robot in motion and “Space bar” stops that motion.

As you move the robot around, you should be able to see walls appearing in the map in RViz and all the other area will be free. After you have mapped the whole environment, you can save the map in config map directory.
Move to map config directory (In another terminal)
```
roscd mcr_default_env_config
```
Then make a directory and move inside that newly created directory
```
mkdir test_map
cd test_map
```
Now you can save the map that you just created
```
rosrun map_server map_saver
```
This will ideally create 2 files namely map.pgm and map.yml. Now you can exit out of mir_2dslam execution. You can also exit from mir_teleop, gazebo, mir_bringup_sim

Making the map usable

In order to use this map in future to navigate, follow the following steps:

Add files where the goals will be saved (in the same directory where the map files have been saved)
```
touch navigation_goals.yaml
touch orientation_goals.yaml
```
Make a copy of the existing launch file.
```
cd ~/catkin_ws/src/mas_common_robotics/mcr_environments/mcr_gazebo_worlds/ros/launch
cp brsu-c025-sim.launch test_map.launch
```
Note

Inside test_map.launch, edit the argument of robot_env (line 10). Replace brsu-c025-sim with test_map. Save this file.

Make a copy of xacro file.

cd ~/catkin_ws/src/mas_common_robotics/mcr_environments/mcr_gazebo_worlds/common/worlds/
cp brsu-c025-sim.urdf.xacro test_map.urdf.xacro

Note

Now your newly created map should be ready for use.

Navigation

Run the commands from “Run simulation related nodes” as mentioned above to bring the robot up.
Launch the navigation node
```
roslaunch mir_2dnav 2dnav.launch
```
Open RViz

Add PoseArray in RViz and change its topic to /particlecloud. Now you will be able to see red arrows around the robot. These arrow show the pose of the robot.
You now need to localize the robot to get its correct pose. Move the robot around the map. (In another terminal)
```
roslaunch mir_teleop teleop_keyboard.launch
```
Rotate the robot in its place using QE keys. You will notice the red arrows converging around the robot. Once the the robot is reasonably localised, you can navigate the robot around in 2 ways:
1. GUI (RViz)
Click on the 2D Nav Goal and select a goal on the map.
1. Terminal based (ROS Action Server Client)
For Action server client, the robot first needs name of position for source and destination places (It cannot use x, y, theta values)

To name the poses, you have to execute save_base_map_poses_to_file
roscd mcr_default_env_config cd test_map rosrun mcr_navigation_tools save_base_map_poses_to_file
This program is terminal based interactive program. The program will ask you to name the position.
You can now navigate the robot to your desired position (using GUI of RViz or mir_teleop).

Once your robot is at the desired position, you can enter a name and press enter.

Note

Note : The name of the location should be ALL CAPS. For example, CORNER_1, MAIN_DOOR, etc. If the name contains any lower case character, the server will not work) You will see pose of the robot inside square brackets in the next line and prompted for another name.

Repeat step 1 and 2 to add multiple names to different locations inside the map.

To close this interactive program, press Ctrl + z. (Note : Ctrl + c won’t work.) Then kill this process.

ps

take a note of the pid of python process.

kill -9 <pid_number>

Now stop mir_2dnav and start it again.

Launch move base launch file (In another terminal)

roslaunch mir_move_base_safe move_base.launch

Run the server file. (In another terminal)

rosrun mir_move_base_safe move_base_safe_server.py

You can test everything by running client test file. (In another terminal)

rosrun mir_move_base_safe move_base_safe_client_test.py SOURCE_NAME DESTINATION_NAME

For example, if you want to move the robot from MAIN_DOOR to CORNER_1, then

rosrun mir_move_base_safe move_base_safe_client_test.py MAIN_DOOR CORNER_1

Note

The source location is irrelevant for the client test file. Your robot can be anywhere and the program will still work correctly. Just give some valid location name as a place holder.) The client will print success : True, if it was able to successfully navigate to the destination position.

RViz setup

Add Map, RobotModel, LaserScan using the “Add” button in bottom left corner of “Display” section of RViz.
In Map, change the topic to /map
In LaserScan, change the topic to /scan_front. Add another LaserScan and change its topic to /scan_rear.
In global option, change the Fixed Frame to map.

Note

You can also add another PoseArray and change its topic to /move_base/GlobalPlannerWithOrientation to visualise the plan created by the mir_2Dnav node.