motion_commander – Simple controls built on Commander

The MotionCommander is used to make it easy to write scripts that move the Crazyflie around. Some sort of positioning support is required, for instance the Flow deck.

The motion commander uses velocity setpoints and does not have a notion of absolute position, the error in position will accumulate over time.

The API contains a set of primitives that are easy to understand and use, such as “go forward” or “turn around”.

There are two flavors of primitives, one that is blocking and returns when a motion is completed, while the other starts a motion and returns immediately. In the second variation the user has to stop or change the motion when appropriate by issuing new commands.

The MotionCommander can be used as context manager using the with keyword. In this mode of operation takeoff and landing is executed when the context is created/closed.

class motion_commander.MotionCommander(commander, func_set_param, default_height=0.3)[source]

The motion commander

Construct an instance of a MotionCommander

Parameters

  • commander – Instance of Commander class

  • func_set_param – Function object ‘set_param(name, value)’

  • crazyflie – A Crazyflie or SyncCrazyflie instance

  • default_height – The default height to fly at

back(distance_m, velocity=0.2)[source]

Go backwards

Parameters

  • distance_m – The distance to travel (meters)

  • velocity – The velocity of the motion (meters/second)

Returns

circle_left(radius_m, velocity=0.2, angle_degrees=360.0)[source]

Go in circle, counter clock wise

Parameters

  • radius_m – The radius of the circle (meters)

  • velocity – The velocity along the circle (meters/second)

  • angle_degrees – How far to go in the circle (degrees)

Returns

circle_right(radius_m, velocity=0.2, angle_degrees=360.0)[source]

Go in circle, clock wise

Parameters

  • radius_m – The radius of the circle (meters)

  • velocity – The velocity along the circle (meters/second)

  • angle_degrees – How far to go in the circle (degrees)

Returns

down(distance_m, velocity=0.2)[source]

Go down

Parameters

  • distance_m – The distance to travel (meters)

  • velocity – The velocity of the motion (meters/second)

Returns

forward(distance_m, velocity=0.2)[source]

Go forward

Parameters

  • distance_m – The distance to travel (meters)

  • velocity – The velocity of the motion (meters/second)

Returns

land(velocity=0.2)[source]

Go straight down and turn off the motors.

Do not call this function if you use the with keyword. Landing is done automatically when the context goes out of scope.

Parameters

velocity – The velocity (meters/second) when going down

Returns

left(distance_m, velocity=0.2)[source]

Go left

Parameters

  • distance_m – The distance to travel (meters)

  • velocity – The velocity of the motion (meters/second)

Returns

move_distance(distance_x_m, distance_y_m, distance_z_m, velocity=0.2)[source]

Move in a straight line. positive X is forward positive Y is left positive Z is up

Parameters

  • distance_x_m – The distance to travel along the X-axis (meters)

  • distance_y_m – The distance to travel along the Y-axis (meters)

  • distance_z_m – The distance to travel along the Z-axis (meters)

  • velocity – The velocity of the motion (meters/second)

Returns

right(distance_m, velocity=0.2)[source]

Go right

Parameters

  • distance_m – The distance to travel (meters)

  • velocity – The velocity of the motion (meters/second)

Returns

start_back(velocity=0.2)[source]

Start moving backwards. This function returns immediately.

Parameters

velocity – The velocity of the motion (meters/second)

Returns

start_circle_left(radius_m, velocity=0.2)[source]

Start a circular motion to the left. This function returns immediately.

Parameters

  • radius_m – The radius of the circle (meters)

  • velocity – The velocity of the motion (meters/second)

Returns

start_circle_right(radius_m, velocity=0.2)[source]

Start a circular motion to the right. This function returns immediately

Parameters

  • radius_m – The radius of the circle (meters)

  • velocity – The velocity of the motion (meters/second)

Returns

start_down(velocity=0.2)[source]

Start moving down. This function returns immediately.

Parameters

velocity – The velocity of the motion (meters/second)

Returns

start_forward(velocity=0.2)[source]

Start moving forward. This function returns immediately.

Parameters

velocity – The velocity of the motion (meters/second)

Returns

start_left(velocity=0.2)[source]

Start moving left. This function returns immediately.

Parameters

velocity – The velocity of the motion (meters/second)

Returns

start_linear_motion(velocity_x_m, velocity_y_m, velocity_z_m, rate_yaw=0.0)[source]

Start a linear motion with an optional yaw rate input. This function returns immediately.

positive X is forward positive Y is left positive Z is up

Parameters

  • velocity_x_m – The velocity along the X-axis (meters/second)

  • velocity_y_m – The velocity along the Y-axis (meters/second)

  • velocity_z_m – The velocity along the Z-axis (meters/second)

  • rate – The angular rate (degrees/second)

Returns

start_right(velocity=0.2)[source]

Start moving right. This function returns immediately.

Parameters

velocity – The velocity of the motion (meters/second)

Returns

start_turn_left(rate=72.0)[source]

Start turning left. This function returns immediately.

Parameters

rate – The angular rate (degrees/second)

Returns

start_turn_right(rate=72.0)[source]

Start turning right. This function returns immediately.

Parameters

rate – The angular rate (degrees/second)

Returns

start_up(velocity=0.2)[source]

Start moving up. This function returns immediately.

Parameters

velocity – The velocity of the motion (meters/second)

Returns

steady(seconds)[source]

Hold steady on set course for specified duration.

stop()[source]

Stop any motion and hover.

Returns

take_off(height=None, velocity=0.2)[source]

Takes off, that is starts the motors, goes straight up and hovers. Do not call this function if you use the with keyword. Take off is done automatically when the context is created.

Parameters

  • height – The height (meters) to hover at. None uses the default height set when constructed.

  • velocity – The velocity (meters/second) when taking off

Returns

turn_left(angle_degrees, rate=72.0)[source]

Turn to the left, staying on the spot

Parameters

  • angle_degrees – How far to turn (degrees)

  • rate – The turning speed (degrees/second)

Returns

turn_right(angle_degrees, rate=72.0)[source]

Turn to the right, staying on the spot

Parameters

  • angle_degrees – How far to turn (degrees)

  • rate – The turning speed (degrees/second)

Returns

up(distance_m, velocity=0.2)[source]

Go up

Parameters

  • distance_m – The distance to travel (meters)

  • velocity – The velocity of the motion (meters/second)

Returns

class motion_commander.SetpointTracker(commander)[source]

Replaces cflib SetPointThread. Track current setpoint and poll/update the commander. * Use self.poll_for(seconds) rather than time.sleep() to keep feeding setpoints. * To do async tasks, you’ll need to call self.update() periodically.

get_height()[source]

Get current height

new_vel(velocity_x, velocity_y, velocity_z, rate_yaw)[source]

New velocity setpoint

poll_for(seconds)[source]

Let it fly!

update()[source]

Poll at 100-200ms rate

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