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High-Level Commander

The high-level commander provides autonomous flight capabilities for the Crazyflie. It handles takeoff, landing, position control, and trajectory execution. All commands require the Crazyflie to have a valid position estimate (from a positioning system like Lighthouse or Loco).

Usage: cfcli hlc <COMMAND>

Commands:
  arm         Arm the Crazyflie (enable motors)
  disarm      Disarm the Crazyflie (disable motors)
  takeoff     Take off to a specified height
  land        Land at the current position
  goto        Go to a specified position
  stop        Stop all high-level commands and disable motors
  trajectory  Trajectory operations
  help        Print this message or the help of the given subcommand(s)

Arm and Disarm

Before flying, the Crazyflie must be armed. This enables the motors and allows the high-level commander to control the drone.

cfcli hlc arm
cfcli hlc disarm

Takeoff

Take off to a specified height. The duration specifies how long it should take to reach the target height.

cfcli hlc takeoff <HEIGHT> [DURATION] [--yaw <YAW>]

Takeoff Examples

# Take off to 0.5 meters over 2 seconds (default)
cfcli hlc takeoff 0.5

# Take off to 1 meter over 3 seconds
cfcli hlc takeoff 1.0 3.0

# Take off to 0.5 meters while rotating to 90 degrees yaw
cfcli hlc takeoff 0.5 --yaw 90

Land

Land at the current position. The height parameter specifies the target landing height (typically 0.0).

cfcli hlc land [HEIGHT] [DURATION] [--yaw <YAW>]

Land Examples

# Land over 2 seconds (default)
cfcli hlc land

# Land over 3 seconds
cfcli hlc land 0.0 3.0

# Land while rotating to 0 degrees yaw
cfcli hlc land --yaw 0

Go To Position

Move to a specified position. The position is given as comma-separated x,y,z coordinates.

cfcli hlc goto <POSITION> [-d <DURATION>] [--yaw <YAW>] [-r]

The position format is x,y,z where x, y, z are coordinates in meters.

Options:

  • -d, --duration: Time in seconds to reach the position (default: 2.0)
  • --yaw: Target yaw in degrees (default: 0)
  • -r, --relative: Move relative to current position

Go To Examples

# Go to position (1, 0, 0.5) over 2 seconds
cfcli hlc goto 1.0,0.0,0.5

# Go to position (1, 2, 1) with 90 degree yaw over 5 seconds
cfcli hlc goto 1.0,2.0,1.0 --yaw 90 -d 5.0

# Move 0.5 meters forward relative to current position
cfcli hlc goto 0.5,0,0 -r

# Negative coordinates are supported
cfcli hlc goto -1.0,-0.5,0.5

# Rotate to 180 degrees yaw while moving
cfcli hlc goto 0.0,0.0,0.5 --yaw 180

Stop

Immediately stop all high-level commander operations and disable the motors.

cfcli hlc stop

Trajectory Operations

Trajectories allow complex pre-defined flight paths to be executed. Trajectories are defined as polynomial segments in a YAML file, uploaded to the Crazyflie's memory, and then executed.

Usage: cfcli hlc trajectory <COMMAND>

Commands:
  upload   Upload a trajectory from a YAML file
  run      Run a previously uploaded trajectory
  display  Display trajectory information (memory info or file contents)

Trajectory File Format

Trajectory files are YAML files containing a list of polynomial segments. Each segment defines a 7th-degree polynomial for x, y, z, and yaw over a specified duration. This format is compatible with the output from the uav_trajectories tool.

segments:
  - duration: 1.5
    x: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
    y: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
    z: [0.0, 0.5, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
    yaw: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
  - duration: 2.0
    x: [0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
    y: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
    z: [0.5, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
    yaw: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

Each segment contains:

  • duration: Time in seconds for this segment
  • x, y, z: 8 polynomial coefficients (constant through 7th degree) for position in meters
  • yaw: 8 polynomial coefficients for yaw angle in radians

The polynomial is evaluated as: p(t) = c[0] + c[1]*t + c[2]*t^2 + ... + c[7]*t^7

Each segment uses 132 bytes of memory on the Crazyflie.

Upload Trajectory

Upload a trajectory from a YAML file to the Crazyflie's trajectory memory.

cfcli hlc trajectory upload <FILE> [-i <ID>] [-o <OFFSET>]

Options:

  • -i, --trajectory-id: Trajectory ID to assign (default: 1)
  • -o, --offset: Memory offset in bytes (default: 0)

Upload Examples

# Upload trajectory with default ID (1)
cfcli hlc trajectory upload my_trajectory.yaml

# Upload trajectory with ID 2
cfcli hlc trajectory upload figure8.yaml -i 2

# Upload multiple trajectories at different offsets
cfcli hlc trajectory upload traj1.yaml -i 1 -o 0
cfcli hlc trajectory upload traj2.yaml -i 2 -o 1000

Run Trajectory

Execute a previously uploaded trajectory.

cfcli hlc trajectory run <ID> [-s <SCALE>] [-r] [-y] [--reversed]

Options:

  • -s, --time-scale: Time scale factor (1.0 = normal, >1.0 = slower, <1.0 = faster)
  • -r, --relative-position: Shift trajectory to start at current position
  • -y, --relative-yaw: Align trajectory yaw to current heading
  • --reversed: Run the trajectory backwards

Run Examples

# Run trajectory ID 1 at normal speed
cfcli hlc trajectory run 1

# Run trajectory at half speed
cfcli hlc trajectory run 1 -s 2.0

# Run trajectory at double speed
cfcli hlc trajectory run 1 -s 0.5

# Run trajectory relative to current position and yaw
cfcli hlc trajectory run 1 -r -y

# Run trajectory in reverse
cfcli hlc trajectory run 1 --reversed

Display Trajectory Info

Display information about a trajectory file or the Crazyflie's trajectory memory.

# Display trajectory file contents
cfcli hlc trajectory display my_trajectory.yaml

# Display trajectory memory info from Crazyflie
cfcli hlc trajectory display

Complete Flight Example

Here's a complete example of a simple flight sequence:

# Select your Crazyflie
cfcli select

# Arm the motors
cfcli hlc arm

# Take off to 0.5 meters
cfcli hlc takeoff 0.5

# Wait a moment (the command returns immediately)
sleep 3

# Move to a position
cfcli hlc goto 1.0,0.0,0.5 -d 2.0
sleep 3

# Move to another position
cfcli hlc goto 0.0,1.0,0.5 -d 2.0
sleep 3

# Return to origin
cfcli hlc goto 0.0,0.0,0.5 -d 2.0
sleep 3

# Land
cfcli hlc land
sleep 3

# Disarm (optional, landing auto-disarms after a delay)
cfcli hlc disarm

Trajectory Flight Example

Example of uploading and running a trajectory:

# Select your Crazyflie
cfcli select

# Check trajectory file contents
cfcli hlc trajectory display figure8.yaml

# Arm and take off
cfcli hlc arm
cfcli hlc takeoff 0.5
sleep 3

# Upload the trajectory
cfcli hlc trajectory upload figure8.yaml -i 1

# Run the trajectory (relative to current position)
cfcli hlc trajectory run 1 -r

# Wait for trajectory to complete, then land
sleep 10
cfcli hlc land