69 lines
2.9 KiB
Python
69 lines
2.9 KiB
Python
"""Randomize the minitaur_gym_env when reset() is called."""
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import random
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import numpy as np
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from . import env_randomizer_base
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# Relative range.
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MINITAUR_BASE_MASS_ERROR_RANGE = (-0.2, 0.2) # 0.2 means 20%
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MINITAUR_LEG_MASS_ERROR_RANGE = (-0.2, 0.2) # 0.2 means 20%
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# Absolute range.
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BATTERY_VOLTAGE_RANGE = (14.8, 16.8) # Unit: Volt
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MOTOR_VISCOUS_DAMPING_RANGE = (0, 0.01) # Unit: N*m*s/rad (torque/angular vel)
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MINITAUR_LEG_FRICTION = (0.8, 1.5) # Unit: dimensionless
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class MinitaurEnvRandomizer(env_randomizer_base.EnvRandomizerBase):
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"""A randomizer that change the minitaur_gym_env during every reset."""
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def __init__(self,
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minitaur_base_mass_err_range=MINITAUR_BASE_MASS_ERROR_RANGE,
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minitaur_leg_mass_err_range=MINITAUR_LEG_MASS_ERROR_RANGE,
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battery_voltage_range=BATTERY_VOLTAGE_RANGE,
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motor_viscous_damping_range=MOTOR_VISCOUS_DAMPING_RANGE):
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self._minitaur_base_mass_err_range = minitaur_base_mass_err_range
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self._minitaur_leg_mass_err_range = minitaur_leg_mass_err_range
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self._battery_voltage_range = battery_voltage_range
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self._motor_viscous_damping_range = motor_viscous_damping_range
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def randomize_env(self, env):
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self._randomize_minitaur(env.minitaur)
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def _randomize_minitaur(self, minitaur):
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"""Randomize various physical properties of minitaur.
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It randomizes the mass/inertia of the base, mass/inertia of the legs,
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friction coefficient of the feet, the battery voltage and the motor damping
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at each reset() of the environment.
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Args:
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minitaur: the Minitaur instance in minitaur_gym_env environment.
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"""
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base_mass = minitaur.GetBaseMassFromURDF()
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randomized_base_mass = random.uniform(
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base_mass * (1.0 + self._minitaur_base_mass_err_range[0]),
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base_mass * (1.0 + self._minitaur_base_mass_err_range[1]))
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minitaur.SetBaseMass(randomized_base_mass)
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leg_masses = minitaur.GetLegMassesFromURDF()
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leg_masses_lower_bound = np.array(leg_masses) * (
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1.0 + self._minitaur_leg_mass_err_range[0])
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leg_masses_upper_bound = np.array(leg_masses) * (
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1.0 + self._minitaur_leg_mass_err_range[1])
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randomized_leg_masses = [
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np.random.uniform(leg_masses_lower_bound[i], leg_masses_upper_bound[i])
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for i in range(len(leg_masses))
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]
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minitaur.SetLegMasses(randomized_leg_masses)
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randomized_battery_voltage = random.uniform(BATTERY_VOLTAGE_RANGE[0],
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BATTERY_VOLTAGE_RANGE[1])
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minitaur.SetBatteryVoltage(randomized_battery_voltage)
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randomized_motor_damping = random.uniform(MOTOR_VISCOUS_DAMPING_RANGE[0],
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MOTOR_VISCOUS_DAMPING_RANGE[1])
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minitaur.SetMotorViscousDamping(randomized_motor_damping)
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randomized_foot_friction = random.uniform(MINITAUR_LEG_FRICTION[0],
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MINITAUR_LEG_FRICTION[1])
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minitaur.SetFootFriction(randomized_foot_friction)
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