|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
"""Randomization functions.""" |
|
|
|
|
|
from __future__ import absolute_import |
|
|
from __future__ import division |
|
|
from __future__ import print_function |
|
|
|
|
|
from dm_control.mujoco.wrapper import mjbindings |
|
|
import numpy as np |
|
|
from six.moves import range |
|
|
|
|
|
|
|
|
def random_limited_quaternion(random, limit): |
|
|
"""Generates a random quaternion limited to the specified rotations.""" |
|
|
axis = random.randn(3) |
|
|
axis /= np.linalg.norm(axis) |
|
|
angle = random.rand() * limit |
|
|
|
|
|
quaternion = np.zeros(4) |
|
|
mjbindings.mjlib.mju_axisAngle2Quat(quaternion, axis, angle) |
|
|
|
|
|
return quaternion |
|
|
|
|
|
|
|
|
def randomize_limited_and_rotational_joints(physics, random=None): |
|
|
"""Randomizes the positions of joints defined in the physics body. |
|
|
|
|
|
The following randomization rules apply: |
|
|
- Bounded joints (hinges or sliders) are sampled uniformly in the bounds. |
|
|
- Unbounded hinges are samples uniformly in [-pi, pi] |
|
|
- Quaternions for unlimited free joints and ball joints are sampled |
|
|
uniformly on the unit 3-sphere. |
|
|
- Quaternions for limited ball joints are sampled uniformly on a sector |
|
|
of the unit 3-sphere. |
|
|
- The linear degrees of freedom of free joints are not randomized. |
|
|
|
|
|
Args: |
|
|
physics: Instance of 'Physics' class that holds a loaded model. |
|
|
random: Optional instance of 'np.random.RandomState'. Defaults to the global |
|
|
NumPy random state. |
|
|
""" |
|
|
random = random or np.random |
|
|
|
|
|
hinge = mjbindings.enums.mjtJoint.mjJNT_HINGE |
|
|
slide = mjbindings.enums.mjtJoint.mjJNT_SLIDE |
|
|
ball = mjbindings.enums.mjtJoint.mjJNT_BALL |
|
|
free = mjbindings.enums.mjtJoint.mjJNT_FREE |
|
|
|
|
|
qpos = physics.named.data.qpos |
|
|
|
|
|
for joint_id in range(physics.model.njnt): |
|
|
joint_name = physics.model.id2name(joint_id, "joint") |
|
|
joint_type = physics.model.jnt_type[joint_id] |
|
|
is_limited = physics.model.jnt_limited[joint_id] |
|
|
range_min, range_max = physics.model.jnt_range[joint_id] |
|
|
|
|
|
if is_limited: |
|
|
if joint_type == hinge or joint_type == slide: |
|
|
qpos[joint_name] = random.uniform(range_min, range_max) |
|
|
|
|
|
elif joint_type == ball: |
|
|
qpos[joint_name] = random_limited_quaternion(random, range_max) |
|
|
|
|
|
else: |
|
|
if joint_type == hinge: |
|
|
qpos[joint_name] = random.uniform(-np.pi, np.pi) |
|
|
|
|
|
elif joint_type == ball: |
|
|
quat = random.randn(4) |
|
|
quat /= np.linalg.norm(quat) |
|
|
qpos[joint_name] = quat |
|
|
|
|
|
elif joint_type == free: |
|
|
quat = random.rand(4) |
|
|
quat /= np.linalg.norm(quat) |
|
|
qpos[joint_name][3:] = quat |
|
|
|
