reachy-mini-daemon or by using the Python module reachy_mini.daemon.app.main.
Reachy Mini's API is designed to be simple and intuitive. You will mostly interact with the ReachyMini class, which provides methods to control the robot's joints such as the head and antennas and interact with its sensors.
The first step is to instantiate the ReachyMini class. This can be done as follows:
from reachy_mini import ReachyMini
mini = ReachyMini()This will connect to the Reachy Mini daemon, which is responsible for managing the hardware communication with the robot's motors and sensors. As soon as the ReachyMini instance is created, it will automatically connect to the daemon and initialize the robot's components.
To ensure that the connection is properly established and cleaned up, it is recommended to use the with statement when working with the ReachyMini class. This will automatically handle the connection and disconnection of the daemon:
from reachy_mini import ReachyMini
with ReachyMini() as mini:
# Your code hereThen, the next step is to show how to move the robot. The ReachyMini class provides methods called set_target and goto_target that allows you to move the robot's head to a specific target position. You can control:
- the head's position and orientation
- the body's rotation angle
- the antennas' position
The head_frame is positioned at the base of the head, as you can see in the image below. This is the frame you are controling when using set_target and goto_target.
For instance, to move the head of the robot slightly to the left then go back, you can use the following code:
from reachy_mini import ReachyMini
from reachy_mini.utils import create_head_pose
with ReachyMini() as reachy:
# Move the head to a specific position
reachy.goto_target(head=create_head_pose(y=-10, mm=True))
# Goes back to the initial position
reachy.goto_target(head=create_head_pose(y=0, mm=True))Let's break down the code:
- First,
create_head_pose(y=-10, mm=True)creates a pose for the head where the y-axis is set to -10 mm. Themm=Trueargument indicates that the value is in millimeters. The pose is a 4x4 transformation matrix that defines the position and orientation of the head. You can print the pose to see its values.
print(create_head_pose(y=-10, mm=True))
>>>
[[ 1. 0. 0. 0. ]
[ 0. 1. 0. -0.01]
[ 0. 0. 1. 0. ]
[ 0. 0. 0. 1. ]]- Then, this matrix is passed to the
goto_targetmethod, as the head target.
The goto_target method accept more arguments, such as duration to specify how long the movement should take. By default, its duration is set to 0.5 seconds, but you can change it to any value you want:
reachy.goto_target(head=create_head_pose(y=-10, mm=True), duration=2.0)You can also orient the head by passing additional arguments to the create_head_pose function. For example, to roll the head 15 degrees while moving it up 10 mm, you can do:
from reachy_mini import ReachyMini
from reachy_mini.utils import create_head_pose
with ReachyMini() as reachy:
# Move the head up (10mm on z-axis) and roll it 15 degrees
pose = create_head_pose(z=10, roll=15, degrees=True, mm=True)
reachy.goto_target(head=pose, duration=2.0)
# Reset to default pose
pose = create_head_pose()
reachy.goto_target(head=pose, duration=2.0)You can also make the antennas move by passing the antennas argument to the goto_target method. For example, to move the antennas to a specific position:
import numpy as np
from reachy_mini import ReachyMini
with ReachyMini() as reachy:
# Move the antennas to a specific position
reachy.goto_target(antennas=np.deg2rad([45, 45]), duration=1.0)
# Reset the antennas to their initial position
reachy.goto_target(antennas=[0, 0], duration=1.0)You need to pass the angles in radians, so you can use numpy.deg2rad to convert degrees to radians. The first value in the list corresponds to the right antenna, and the second value corresponds to the left antenna.
You can also move the head, the body and the antennas at the same time by passing all three arguments to the goto_target method:
import numpy as np
from reachy_mini import ReachyMini
from reachy_mini.utils import create_head_pose
with ReachyMini() as reachy:
# Move the head and antennas to a specific position
reachy.goto_target(
head=create_head_pose(y=-10, mm=True),
antennas=np.deg2rad([45, 45]),
duration=2.0,
body_yaw=np.deg2rad(30)
)Finally, you can also select the interpolation method used. By default, the interpolation method is set to "minjerk", but you can change it to "linear", "cartoon" or "ease".
import numpy as np
from reachy_mini import ReachyMini
from reachy_mini.utils import create_head_pose
with ReachyMini() as reachy:
# Move the head and antennas to a specific position
reachy.goto_target(
head=create_head_pose(y=10, mm=True),
antennas=np.deg2rad([-45, -45]),
duration=2.0,
method="cartoon", # can be "linear", "minjerk", "ease" or "cartoon"
)If you want to test the different interpolation methods, you can run the goto_interpolation_playground.py example, which will illustrate the differences between the interpolation methods when running the goto_target method.
You can also use the set_target method to set the target position of the head and antennas. It will use the same head pose and antennas arguments. This method is useful if you want the robot to move immediately to a specific position without any interpolation. It can be useful to control the movement at a high frequency. For example, to make the head follows a sinusoidal trajectory:
import time
import numpy as np
from reachy_mini import ReachyMini
from reachy_mini.utils import create_head_pose
with ReachyMini() as reachy:
# Set the initial target position
reachy.set_target(head=create_head_pose(y=0, mm=True))
start = time.time()
while True:
# Calculate the elapsed time
t = time.time() - start
if t > 10:
break # Stop after 10 seconds
# Calculate the new target position
y = 10 * np.sin(2 * np.pi * 0.5 * t) # Sinusoidal trajectory
# Set the new target position
reachy.set_target(head=create_head_pose(y=y, mm=True))
time.sleep(0.01)When it comes to the reachy mini's head, it is important to note that it has several physical limitations of its head and body position and orientation capabilities. Such as:
- The robots motors have a limited range of motion
- The robot's head can collide with the body
- The robot's body rotation (body yaw) is limited to [-180, 180] degrees.
In addition to the physical limitations, the robot has several software safety features that limit the head's position and orientation. These safety features are designed to prevent the robot from moving to unsafe positions or orientations that could cause damage to the robot or its surroundings.
- The head's pitch and roll angles are limited to [-40, 40] degrees.
- The head's yaw angle is limited to [-180, 180] degrees
- The difference between the body yaw and head yaw angles is limited to [-65, 65] degrees.
If any of these limits are exceeded, the robot will move to the closest valid position within the limits.
For example, if you try to move the head to an orientation that exceeds the limits, such as:
reachy.goto_target(head=create_head_pose(roll=-50, degrees=True))The robot will not be able to follow due to the safety limit 4.
Or another example, if you try to move the body yaw to an angle that exceeds the limits, such as:
reachy.goto_target(
head=create_head_pose(yaw=10, degrees=True), body_yaw=np.deg2rad(100)
)The robot will not be able to follow the command exactly due to the safety limit 6.
Reachy mini will not throw an error if you exceed these limits, but it will move to the closest valid position within the limits. You can check the current position of the head using the get_current_head_pose method of the ReachyMini instance. For example:
import time
from reachy_mini import ReachyMini
from reachy_mini.utils import create_head_pose
reachy = ReachyMini()
# construct a head pose with roll -20 degrees
pose = create_head_pose(roll=-20, degrees=True)
reachy.goto_target(head=pose)
time.sleep(1) # wait for the movement to complete
# get the current head pose
head_pose = reachy.get_current_head_pose()
print("current head pose", head_pose)
print("target head pose", pose)To make the robot look at a specific point, we provide look_at methods.
The look_at_image method allows the robot to look at a point in the image coordinates. The image coordinates are defined as a 2D point in the camera's image plane, where (0, 0) is the top-left corner of the image and (width, height) is the bottom-right corner. Similarly to the goto_target method, you can specify the duration of the movement.
You can see the example in look_at_image.py.
There is also a look_at_world method that allows the robot to look at a point in the world coordinates. The world coordinates are defined as a 3D point in the robot's coordinate system.
You can control the robot's motors with three main methods:
-
enable_motors: Powers on the motors, making the robot ready to move and respond to commands. In this mode, the robot holds its position and you cannot move it by hand. -
disable_motors: Powers off the motors. The robot will not respond to commands, but you can move it freely by hand (no resistance). -
make_motors_compliant: Makes the motors compliant (requires motors to be enabled first). In this mode, the motors are powered on, but they do not resist external forces, so you can move the robot by hand, and it will feel "soft". This is useful for safe manual manipulation or teaching by demonstration. For an example, see the gravity compensation example: in this demo, you can move the robot's head and antennas freely, but the robot will use its motors to compensate for gravity and maintain its position/orientation in space.
Let's assume that you have a script that uses the set_target fonction to move the robot and you want to record the commands to be able to replay them.
For example, this could be a teleoperation script, and you could be recording cute emotions (OK this is how we did it).
You can create another ReachyMini client (or use the same) and simply use start_recording() and stop_recording().
Below is the snippet of code that show how to start a recording, stop the recording and unpack the data:
import time
from reachy_mini import ReachyMini
with ReachyMini() as mini:
data = {
"description": "TODO: describe what you captured.",
"time": [],
"set_target_data": [],
}
try:
# The daemon will start recording the set_target() calls
mini.start_recording()
print("\nRecording started. Press Ctrl+C here to stop recording.")
while True:
# Keep the script alive to listen for Ctrl+C
time.sleep(0.01)
except KeyboardInterrupt:
# Stop recording and retrieve the logged data
recorded_motion = mini.stop_recording()
for frame in recorded_motion:
data["time"].append(frame.get("time"))
pose_info = {
"head": frame.get("head"),
"antennas": frame.get("antennas"),
"body_yaw": frame.get("body_yaw"),
}
data["set_target_data"].append(pose_info)We also provide tools to record and upload a dataset to the hub, that can be easily replayed later. See This section
Reachy Mini comes with several sensors (camera, microphone, speaker) that are connected to your computer via USB through the robot. These devices are accessible via the reachy_mini.media object.
A camera frame can be easily retrieved as follows:
from reachy_mini import ReachyMini
with ReachyMini() as reachy_mini:
while True:
frame = reachy_mini.media.get_frame()
# frame is a numpy array as output by opencvPlease refer to the example: look_at_image.
Audio samples from the microphone can be obtained as follows:
from reachy_mini import ReachyMini
with ReachyMini() as mini:
while True:
sample = mini.media.get_audio_sample()
# sample is a numpy array as output by sounddevicePlease refer to the example sound_record.
Audio samples can be pushed to the speaker as follows:
from reachy_mini import ReachyMini
with ReachyMini() as mini:
while True:
# get audio chunk from mic / live source / file
mini.media.push_audio_sample(chunk)Please refer to the example: sound_play.
By default, OpenCV manages the camera, and sounddevice manages the audio. Advanced users can use the GStreamer backend, which enables the creation of more complex media pipelines and provides better control over audio/video latency. The above examples can be started with the --backend gstreamer argument.
To enable the use of the GStreamer backend, the package should be installed as follows:
pip install -e ".[gstreamer]"It is assumed that the gstreamer binaires are properly installed on your system. You will likely want to configure your own pipeline. See gstreamer camera for an example.
You can also play predefined moves simply. You can find an example on how to do this in the recorded moves example examples.
Basically, you just need to load the move from the dataset you want. And run the play_move method on a ReachyMini instance.
from reachy_mini import ReachyMini
from reachy_mini.motion.recorded_move import RecordedMoves
with ReachyMini() as mini:
recorded_moves = RecordedMoves("pollen-robotics/reachy-mini-dances-library")
print(recorded_moves.list_moves())
for move_name in recorded_moves.list_moves():
print(f"Playing move: {move_name}")
mini.play_move(recorded_moves.get(move_name), initial_goto_duration=1.0)The initial_goto_duration argument for play_move() allows you to smoothly go to the starting position of the move before starting to execute it.
The datasets are hosted on the Hugging Face Hub (for example)
We provide tools to record and upload a dataset here.
We provide a simple way to wrap your behavior in an application that can be run as a standalone script. This is useful to properly manage the start/stop of the app and to add discovery/install mechanisms to allow users to easily run your app. We are also working on a dashboard to manage the apps and their installation.
It is also a good way to share your app with the community and make it easily discoverable and installable! See the HF Spaces Reachy Mini Apps for examples of apps shared by the community.
To write your app, you simply need to define a class that inherits from ReachyMiniApp and implements the run method. This method will be called when the app is started, and you can use it to interact with the robot.
import threading
from reachy_mini.apps.app import ReachyMiniApp
from reachy_mini import ReachyMini
class MyApp(ReachyMiniApp):
def run(self, reachy_mini: ReachyMini, stop_event: threading.Event):
# Write your code here
...The stop_event is a threading event that you should check periodically to know if the app should stop. You can use it to gracefully stop the app when the user wants to stop it.
Directly go to HF Spaces Reachy Mini App Example and follow the instruction!
We also provide a script to make all the basic boilerplate for you. You can run the following command to create a new app:
reachy-mini-make-app my_app_nameThis will create a new directory called my_app_name with the following structure:
my_app_name/
├── pyproject.toml
├── README.md
├── my_app_name/
│ ├── __init__.py
│ └── main.py
You can run your app directly as a script:
python my_app_name/main.pyor install it as a package:
pip install -e my_app_name/