Naming Conventions

An overview of the nodes and topics is in our repository: Node Overview (open with inkscape)

Topics

• sailing_state
• wind_direction_apparent
• wind_direction_real
• wind_direction_average
• wind_speed_apparent
• wind_speed_real
• heading
• pitch
• roll
• goal_heading
• imu
• current_wp
• gps
• gps_satellites
• position
• position_error
• PoS_control
• tack_sail
• rudder_control
• tack_rudder
• distance_to_waypoint
• heading_to_waypoint
• camera_detection
• remote_control
• temporary_wp

Debug topics

• debug_sailsheet_normalized
• debug_sailsheet_pwm
• led_blink
• debugging_2D_plot
• debugging_2D_plot_origin
• debugging_2D_plot_wp
• gps_fix
• gpd_satellites
• mag_x_comp
• mag_y_comp
• mag_x
• mag_y
• mag_z

coordinate system

The coordinate system of the boat is z-axis down, y-axis point to star port. See the picture below:

sailing_state

Data type: [String]

• 'normal' sail towards goal heading
• 'tack_to_port_tack' and 'tack_to_stbd_tack'overwrites goal heading

wind_direction_apparent

Data type: [Float64]

• angle 0 to 360 degrees, giving the direction the wind is coming from, relative to the boat; 0 degrees means boat is heading directly upwind (see figure below)

wind_direction_real

Data type: [Float32]

• angle 0 to 360 degrees, giving an estimate of the actual direction the wind is coming from, 0 degrees is North (see figure below)

wind_direction_average

Data type: [Float32]

• angle 0 to 360 degrees, giving the average direction the wind is coming from, 0 degrees is North (see figure below)

wind_speed_apparent

Data type: [Float64]

• Speed in m/s

wind_speed_real

Data type: [Float32]

• Speed in m/s

heading

Data type: [Float32]

• angle 0 to 360 degrees, giving the current heading of the boat; 0 degrees is North (see figure below)

pitch

Data type: [Float32]

• pitch angle in radian between -pi and pi based on the accelerometer

roll

Data type: [Float32]

• roll angle in radian between -pi and pi based on the accelerometer

goal_heading

Data type: [Float32]

• angle 0 to 360 degrees, heading that the boat is currently trying to achieve; 0 degrees is North (see figure below)

imu

Data type: self defined msg

• accx [Float32]
• accy [Float32]
• accz [Float32]
• gyrox [Float32]
• gyroy [Float32]
• gyroz [Float32]
• magx [Float32]
• magy [Float32]
• magz [Float32]

current_wp

Data type: nmea NavSatFix: sensor_msgs/NavSatFix

• next point the path planning wants the boat to head to

gps

Data type: nmea NavSatFix: sensor_msgs/NavSatFix

• rough position from the gps

gps_satellites

Data type: [Int16]

• Number of satellites detected by the GPS

position

Data type: nmea NavSatFix: sensor_msgs/NavSatFix

• estimate of the position based on imu and gps

position_error

Data type: [Float32]

• In meters, giving the absolute error in global position.

PoS_control

Data type: [Float32]

• In degrees, giving the angle at which the sail should be, based on current heading and wind speed (see figure above)

sail_servo

Data type: [UInt16]

• In degrees, giving maximum winch servo the control angle (0 to 90)

tack_sail (OVERWRITES: PoS_control)

Data type: [Float32]

• In degrees, giving the angle at which the sail should be for completing a tack

rudder_control

Data type: [Int16]

• In degrees, giving the angle at which the rudder should be for achieving the current goal heading (see figure above)

tack_rudder (OVERWRITES: rudder_control)

Data type: [Float32]

• In degrees, giving the rudder angle for completing a tack manoeuvre

distance_to_waypoint

Data type: [Float32]

• In metres, the cartesian distance between the boat's GPS location and the active waypoint. Only published while the current task is sailing to a waypoint.

heading_to_waypoint

Data type: [Float32]

• The heading from the boat's GPS location to the active waypoint. Only published while the current task is sailing to a waypoint.

camera_detection

Data type: [String]

• publish nothing when nothing is detected, and detected when something is detected

Debug topics

debug_sailsheet_normalized

Data type: [Float32]

• The servo setting for the sail normalized between 0 and 1, 0 representing the sheet being fully in, 1 the sheet being fully out

debug_sailsheet_pwm

Data type: [Float32]

• raw PWM value given to the sail pin

led_blink

Data type: [Int32]

• rgb values given as an int with a shift of 300:

• red= 255*300*300 + 0*300 + 0
• green= 0*300*300 + 255*300 + 0
• lilac= 200*300*300 + 162*300 + 200

debugging_2D_plot

Data type: [MarkerArray]

• Pulish the history of the boat position for RViz

debugging_2D_plot_origin

Data type: [NavSatFix]

• Pulish map origin position for RViz

debugging_2D_plot_wp

Data type: [MarkerArray]

• Pulish the waypoints for RViz

gps_fix

Data type: [gpswtime]

• Publish the gps time as well as the boat position

gps_satellites

Data tyoe: [Int16]

• Publish the amount of satellites visible by the gps

mag_x_comp

Data type: [Float32]

• magnetometer X compensated

mag_y_comp

Data type: [Float32]

• magnetometer Y compensated

mag_x

Data type: [Float32]

• raw magnetometer X

mag_y

Data type: [Float32]

• raw magnetometer Y

mag_z

Data type: [Float32]

• raw magnetometer Z

Messages

velocity

Data type: self defined msg

• velx [Float32]
• vely [Float32]
• velz [Float32]

gpswtime

Data type: self defined msg

• fix [NavSatFix]
• time_h [uint16]
• time_m [uint16]
• time_s [uint16]

Parameters

The parameters are defined in yaml files in the sailing_robot/launch/parameters folder. A few notes on parameters:

• make sure you add a comment above each parameter, explaining it and specifying what units it is in
• getting parameters from the parameter server takes noticeably time (tens of ms), so don't use it in loops
• parameters are values that may change from experiment to experiment, but not during the experiment
• think python dictionary! Parameters can be interpreted as python dictionaries containing python dictionaries...
• more information: ROS wiki

Internal variables

goal_$$$

the output to be published