# TiCare Navigation Architecture

## `ticare_interfaces`

- **Description:** Custom service and message definitions for the TiCare ecosystem.
    
- **Service:** `SavePose.srv`: 
    - Request: `string label` 
    - Response: `bool success`, `string message`
    
- **Dependencies:** `rosidl_default_generators` (buildtool_depend), `rosidl_default_runtime` 
(exec_depend), `rosidl_interface_packages` (member_of_group)
    

## `ticare_navigation`

- **Description:** Implementation of the navigation stack, pose recording, and state management.

- **Launch:** 
    - `ticare_navigation.launch.py`:  Main launch file. Launch rviz and `ticare_nodes.launch.py` for 
    real-world operation.
    - `ticare_nodes.launch.py`: Launches the `nav_manager` and `pose_recorder` nodes.
    - `ticare_sim.launch.py`: Launches PAL Robotics packages simulation  with specific arguments.
    - `navigation_public_sim_ticare.launch.py`: Configures Tiago simulation with custom map.

- **Maps:**
    Each map is defined by a `.pgm` and a `.yaml` file:
    - `final_map`: Map used for navigation in the simulation, merge of `map` and `map_juan`.
    - `map`: Map of the entire CAR with some errors.
    - `map_juan`: Map of the Lab in the CAR.
    - `lab`: Map of the Lab, first iteration.

- **Rviz:**
    - `rviz_ticare_config.rviz`: Custom RViz configuration for `ticare_sim.launch.py`.

- **Scripts:**
    - `modify_poses.py`: Shifts the original `car.world` by modifying the poses of each block.

- **Worlds:**

    - `car`: Original world.
    - `car_shifted_final_block`: Shifted world to match the spawning point with the real world 
    location of TIAGo, using tables as blocks to ensure robust navigation.

    There are other iterations of the maps that have been obtained by hand editing or implementing 
    python scripts.



- **Node:** `nav_manager`

    - **Description:** High-level orchestrator that monitors localization quality (AMCL) and manages
    state transitions (Search, Navigation, Emergency).
        
    - **Interfaces:**
        - **Publishers:**
            
            - `/nav2vis` (`std_msgs/msg/String`): Sends commands (_"start_vis", "stop_vis"_) to the 
            `ticare_vision` package to activate or deactivate the camera during the search phase.
            - `/nav2com` (`std_msgs/msg/String`): Communicates mission status (_"home"_, 
            _"object_point"_) to the `ticare_communication` package.
            - `/cmd_vel` (`geometry_msgs/msg/Twist`): Sends velocity commands to rotate if the 
            initial localization accuracy is insufficient. 
        
        - **Subscribers:**
            
            - `/vis2nav` (`std_msgs/msg/String`): Receives object detection status 
            (_"object_detected"_) from `ticare_vision` package.
            - `/com2nav` (`std_msgs/msg/String`): Receives mission start commands (_"start_nav"_, 
            _"return"_) from `ticare_communication` package.
                
        - **Service Clients:**
            
            - `/save_pose` (`ticare_interfaces/srv/SavePose`): Request to record start or target 
            points.
                
        - **Action Clients:**
            
            - `/navigate_to_pose` (`nav2_msgs/action/NavigateToPose`): Sends the robot to the target using A* algorithm.
            - `/follow_waypoints` (`nav2_msgs/action/FollowWaypoints`): Executes coverage path 
            planning.
                
    - **Entry Point:** `ticare_navigation.nav_manager:main`
        
    - **Dependencies:** `rclpy`, `ticare_interfaces`, `geometry_msgs`.
        

- **Node:** `pose_recorder`

    - **Description:** Persistence node responsible for receiving poses and storing them in YAML
    format.
        
    - **Interfaces:**
        - **Subscribers:**
        
            - `/amcl_pose` (`geometry_msgs/msg/PoseWithCovarianceStamped`): Catches the current pose
            for immediate saving.
        
        - **Service Servers:**
            
            - `/save_pose` (`ticare_interfaces/srv/SavePose`): Receives a label and saves the 
            current pose.
                
    - **Entry Point:** `ticare_navigation.pose_recorder:main`
        
    - **Dependencies:** `rclpy`, `ticare_interfaces`, `geometry_msgs`, `rosidl_runtime_py`.