Python API

start_joystick
link_joy_button
take_off
stop
emergency
land
set_mode
set_formation
next_formation
prev_formation
inc_scale
dec_scale
toggle_ctrl_mode
go_to
get_positions
rotate_formation

Python API to control the swarm.

This module maked it possible to easily send command to the swarm through a Python script.

Example

# Formation exemple
swarm = SwarmAPI()

# Link joystick buttons to commands
swarm.start_joystick("ds4")
swarm.link_joy_button("S", swarm.take_off)
swarm.link_joy_button("X", swarm.land)
swarm.link_joy_button("O", swarm.emergency)
swarm.link_joy_button("T", swarm.toggle_ctrl_mode)

# Start swarm
swarm.set_mode("formation")
swarm.set_formation("v")

swarm.take_off()
rospy.sleep(10)

# Change formation
swarm.set_formation("pyramid")

SwarmAPI class

class swarm_api.api.SwarmAPI

Python API class

start_joystick(joy_type, joy_dev='js0')

Initialize joystick node. See here for a tutorial on how to add new joystick types.

Possible types:

• ds4

Parameters:

• joy_type (str) – Controller type.
• joy_dev (str, Optional) – Specify joystick port. Defaults to js0

set_joy_control(to_control)

To enable/disable control of formation position with joystick axes.

Parameters:to_control (bool) – If True, formation will be moved by joystick axes

link_joy_button(button_name, func, args=None, kwargs=None)

Link a button to a function call

Parameters:

• button_name (str) – Name of button, as written in joy_conf.yaml.
• func (Callable) – Function to call
• args (optional) – Function args. Defaults to None. Can be a single arg or a list of args
• kwargs (dict, optional) – Function kwargs. Defaults to None.

Raises:

KeyError – Invalid button name

Example:

swarm.start_joystick("ds4")
swarm.link_joy_button("S", swarm.take_off)
swarm.link_joy_button("X", swarm.land)

take_off()

Take off all landed CFs.

Modify take_off_height in swarm_conf.yaml to change take off height

Note

Will only take off landed CFs

stop()

Stop all CFs

emergency()

Call emergency srv of all CFs

land()

Land all CFs at their starting position.

set_mode(new_mode)

Set SwarmController control mode.

Possible modes are:

• Automatic: CF will plot trajectory to new goals. Send go_to commands from python script
• Formation: Swarm moves in formation. Formation position can be moved /w joystick.

Not implemented:

• Pilot: Like CF client. No formation
• Assisted: Control change of position /w joystick. No formation.

Note

Modes are not case sensitive

Parameters:new_mode (str) – New control mode

set_formation(formation_name)

Set swarn formation

Parameters:formation_name (str) – New formation name

next_formation()

Go to next swarm formation

prev_formation()

Go to prev swarm formation

inc_scale()

Increase formation scale by 0.5

dec_scale()

Decrease formation scale by 0.5

toggle_ctrl_mode()

Toggle control mode between absolute and relative.

In absolute: x, y, z are world axis

In relative: x, y, z depends on swarm orientation

go_to(goals)

Move formation and/or cf to a position using the trajectory planner.

Dict format: "goal_name": [x, y, z, yaw] where "goal_name" is either "formation" or "cf_x"

X, Y, Z in meters, Yaw in rad.

Example::

# To move formation to [2, 2, 0.5, 1.57] swarm.go_to({‘formation’: [2, 2, 0.5, 1.57]})

# To move cf_0 to [0, 0, 0.5] and cf_1 to [1, 1, 1] goals = {} goals[“cf_0”] = [0, 0, 0.5, 0] goals[“cf_1”] = [1, 1, 1, 0] swarm.go_to(goals)

Parameters:goals (dict) – New goals

get_positions(cf_list=None)

Get current position of crazyflies

If cf_list is None, will return position of all Cfs.

Parameters:cf_list (list, optional) – List of cf to read positions. Defaults to None. Returns:Positions of CFs read. "{cf_id": [x, y, z, yaw], ...} Return type:dict

rotate_formation(angle, duration)

Rotate formation around it’s center

Note

Formation control with joystick must be False to use this function swarm.set_joy_control(False)

Parameters:

• angle (float) – Angle to turn [deg]
• duration (float) – Rotation duration [sec]