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@erwincoumans @wenkesj @araffin
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"""
Classic cart-pole system implemented by Rich Sutton et al.
Copied from https://webdocs.cs.ualberta.ca/~sutton/book/code/pole.c
"""
import os, inspect
currentdir = os.path.dirname(os.path.abspath(inspect.getfile(inspect.currentframe())))
parentdir = os.path.dirname(os.path.dirname(currentdir))
os.sys.path.insert(0, parentdir)
import logging
import math
import gym
from gym import spaces
from gym.utils import seeding
import numpy as np
import time
import subprocess
import pybullet as p
import pybullet_data
from pkg_resources import parse_version
logger = logging.getLogger(__name__)
class CartPoleBulletEnv(gym.Env):
metadata = {'render.modes': ['human', 'rgb_array'], 'video.frames_per_second': 50}
def __init__(self, renders=True):
# start the bullet physics server
self._renders = renders
if (renders):
p.connect(p.GUI)
else:
p.connect(p.DIRECT)
self.theta_threshold_radians = 12 * 2 * math.pi / 360
self.x_threshold = 0.4 #2.4
high = np.array([
self.x_threshold * 2,
np.finfo(np.float32).max, self.theta_threshold_radians * 2,
np.finfo(np.float32).max
])
self.force_mag = 10
self.action_space = spaces.Discrete(2)
self.observation_space = spaces.Box(-high, high, dtype=np.float32)
self.seed()
# self.reset()
self.viewer = None
self._configure()
def _configure(self, display=None):
self.display = display
def seed(self, seed=None):
self.np_random, seed = seeding.np_random(seed)
return [seed]
def step(self, action):
force = self.force_mag if action == 1 else -self.force_mag
p.setJointMotorControl2(self.cartpole, 0, p.TORQUE_CONTROL, force=force)
p.stepSimulation()
self.state = p.getJointState(self.cartpole, 1)[0:2] + p.getJointState(self.cartpole, 0)[0:2]
theta, theta_dot, x, x_dot = self.state
done = x < -self.x_threshold \
or x > self.x_threshold \
or theta < -self.theta_threshold_radians \
or theta > self.theta_threshold_radians
done = bool(done)
reward = 1.0
#print("state=",self.state)
return np.array(self.state), reward, done, {}
def reset(self):
# print("-----------reset simulation---------------")
p.resetSimulation()
self.cartpole = p.loadURDF(os.path.join(pybullet_data.getDataPath(), "cartpole.urdf"),
[0, 0, 0])
p.changeDynamics(self.cartpole, -1, linearDamping=0, angularDamping=0)
p.changeDynamics(self.cartpole, 0, linearDamping=0, angularDamping=0)
p.changeDynamics(self.cartpole, 1, linearDamping=0, angularDamping=0)
self.timeStep = 0.02
p.setJointMotorControl2(self.cartpole, 1, p.VELOCITY_CONTROL, force=0)
p.setJointMotorControl2(self.cartpole, 0, p.VELOCITY_CONTROL, force=0)
p.setGravity(0, 0, -9.8)
p.setTimeStep(self.timeStep)
p.setRealTimeSimulation(0)
randstate = self.np_random.uniform(low=-0.05, high=0.05, size=(4,))
p.resetJointState(self.cartpole, 1, randstate[0], randstate[1])
p.resetJointState(self.cartpole, 0, randstate[2], randstate[3])
#print("randstate=",randstate)
self.state = p.getJointState(self.cartpole, 1)[0:2] + p.getJointState(self.cartpole, 0)[0:2]
#print("self.state=", self.state)
return np.array(self.state)
def render(self, mode='human', close=False):
return
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