skydio_x2_description

URDF description of Skydio X2 quadrotor

It is derived from publicly available MJCF description and transformed to URDF manually.

Usage

Model can be easily loaded to various libraries such as pinocchio.

For proper simulation one should use specific selector matrix pre-multiplying the input vector of the actuators. Input from actuators should be only positive.

import pinocchio as pin
import numpy as np

model = pin.buildModelFromUrdf("urdf/skydio_x2.urdf")
data = model.createData()

# Selector matrix for actuators
selector = np.array(
    [
        [0.0, 0.0, 0.0, 0.0],
        [0.0, 0.0, 0.0, 0.0],
        [1.0, 1.0, 1.0, 1.0],
        [-0.18, 0.18, 0.18, -0.18],
        [0.14, 0.14, -0.14, -0.14],
        [-0.0201, 0.0201, 0.0201, -0.0201],
    ]
)

# joint-space force
qfrc_u = selector @ np.array([tau1, tau2, tau3, tau4])

Derivation of the selector matrix is described in this notebook.

Notice, that much attention is put towards dynymics matching the MuJoCo model, collisions are not considered and will be welcomed as a contribution.