UAL interfaces

There are two ways of interfacing with UAL: directly via a C++ object of class UAL, and via ROS services/topics.

C++ class interface

The UAL class is defined in ual.h. You can directly create one UAL object in your app and access its public methods:

• takeOff(double _height, bool _blocking = true) Perform a take off maneuver
• goToWaypoint(const Waypoint& _wp, bool _blocking = true) Go to the specified waypoint smoothly, following a straight line
• goToWaypointGeo(const WaypoinGeot& _wp, bool _blocking = true) Same as goToWaypoint but in geographic coordinates
• land(bool _blocking = true) Land on the current position
• recoverFromManual() Recover from manual flight mode
• setHome(bool set_z = false) Set current pose as home. Set x, y and optionally z to zero.
• setPose(const PoseStamped& _pose) Set the specified pose as a reference to position control
• setVelocity(const Velocity& _vel) Set the specified velocity as a reference to velocity control
• pose() Get the latest pose estimation of the robot
• velocity() Get the latest velocity estimation of the robot
• odometry() Get the latest odometry estimation of the robot
• transform() Get the latest transform estimation of the robot
• state() Get current system state: UNINITIALIZED, LANDED_DISARMED, LANDED_ARMED, TAKING_OFF, FLYING_AUTO, FLYING_MANUAL, LANDING.

ROS interface

The UAL class offers a ROS interface based on topics and services. It can be disabled if the parameter ual_server is set to off.

Services

Each service provides access to each corresponding method:

• ual/take_off
• ual/go_to_waypoint
• ual/go_to_waypoint_geo
• ual/land
• ual/recover_from_manual
• ual/set_home

Topics

The system subscribes to topics that then uses to set pose and velocity to low level control:

• ual/set_pose
• ual/set_velocity

At the same time and at a frequency defined by parameter ~pub_rate (30Hz by default), it publishes the information got from the corresponding info methods:

• ual/pose
• ual/velocity
• ual/odom
• /tf, /tf_static
• ual/state