Reachy Mini Motion Philosophy

from reachy_mini import ReachyMini
from reachy_mini.utils import create_head_pose

with ReachyMini() as mini:
    pose = create_head_pose(yaw=30, pitch=10, degrees=True)
    mini.goto_target(head=pose, duration=1.0, method="minjerk")

Interpolation Methods

Key Insight

During goto_target() interpolation, you cannot react to external stimuli. The robot commits to completing the movement. This is fine for:

• Playing emotions
• Choreographed sequences
• Transitioning between states

set_target(): For Real-Time Control

Use this when you need to react every frame (face tracking, games, joystick).

Requirements:

• Must run in a control loop at 50-100 Hz
• Single place in code calling set_target()
• Keep sending targets even when "idle"

See reachy-mini-control-loops.md for implementation details.

Decision Flowchart

Does your app need to react to input/sensors in real-time?
├── NO → Use goto_target()
│        - Simpler code
│        - Guaranteed smooth motion
│        - Good for: emotions, dances, scripted sequences
│
└── YES → Use set_target() in a control loop
          - More complex but fully reactive
          - You control smoothing
          - Good for: tracking, games, recording

Common Mistake

Don't do this:

# BAD: Multiple set_target calls scattered in code
def on_face_detected(face):
    mini.set_target(head=look_at_face(face))

def on_button_press():
    mini.set_target(head=neutral_pose)

def idle_behavior():
    mini.set_target(head=breathing_pose)

Do this instead:

# GOOD: Single control loop, update target variables
def control_loop():
    while running:
        pose = compute_final_pose()  # Combines all inputs
        mini.set_target(head=pose)
        time.sleep(0.01)

def on_face_detected(face):
    controller.face_target = look_at_face(face)

def on_button_press():
    controller.override = neutral_pose