Robot controller that performs some basic safety task on top of the Husqvarna driver node (am_driver_safe).

This node:

• Puts the Husqvarna driver into a known good state (loop detection off, manual control, ...)
• Performs keep alive handling on cmd_vel for safety.
• Handles collisions.
• Translates idiosyncratic battery & system status messages to more useful information for other components.
• Implements functionality to exit the charging station, as that is non-obvious.

Subscribed from front end:

• cmd_vel (geometry_msgs/Twist) - Commanded driving speed. Keep-alive by repeated messages required or the robot will automatically stop.

Published to front end:

• battery/a (sensor_msgs/BatteryState) - Battery state for battery A
• battery/b (sensor_msgs/BatteryState) - Battery state for battery B
• battery/status (oru_ipw_controller/SimpleBatteryStatus) - Simplified battery status for web GUI.

Subscribed from Husqvarna driver:

• hrp/battery_status (am_driver/BatteryStatus) - Low level battery status
• hrp/current_status (am_driver/CurrentStatus) - Low level system status
• hrp/sensor_status (am_driver/SensorStatus) - Low level system status

Published to Husqvarna driver:

• hrp/cmd_mode (std_msgs/UInt16) - Mode control
• hrp/cmd_vel (geometry_msgs/Twist) - Velocity command

For usage from front end:

• exit_charging_station (std_srvs/Trigger) - Trigger an attempt to exit the charging station.

Called on the Husqvarna driver:

• hrp/tif_command (am_driver_safe/TifCmd) - Used to control headlights.

• ~drive_timeout (double, default: 0.5) - Stop if no velocity command received within this time period [s]
• ~low_battery_level (double, default: 18.0) - Voltage below which batteries are considered low.