robot_pendula.py

from robot_bases import MJCFBasedRobot
import numpy as np


class InvertedPendulum(MJCFBasedRobot):
  swingup = False

  def __init__(self):
    MJCFBasedRobot.__init__(self, 'inverted_pendulum.xml', 'cart', action_dim=1, obs_dim=5)

  def robot_specific_reset(self, bullet_client):
    self._p = bullet_client
    self.pole = self.parts["pole"]
    self.slider = self.jdict["slider"]
    self.j1 = self.jdict["hinge"]
    u = self.np_random.uniform(low=-.1, high=.1)
    self.j1.reset_current_position(u if not self.swingup else 3.1415 + u, 0)
    self.j1.set_motor_torque(0)

  def apply_action(self, a):
    assert (np.isfinite(a).all())
    if not np.isfinite(a).all():
      print("a is inf")
      a[0] = 0
    self.slider.set_motor_torque(100 * float(np.clip(a[0], -1, +1)))

  def calc_state(self):
    self.theta, theta_dot = self.j1.current_position()
    x, vx = self.slider.current_position()
    assert (np.isfinite(x))

    if not np.isfinite(x):
      print("x is inf")
      x = 0

    if not np.isfinite(vx):
      print("vx is inf")
      vx = 0

    if not np.isfinite(self.theta):
      print("theta is inf")
      self.theta = 0

    if not np.isfinite(theta_dot):
      print("theta_dot is inf")
      theta_dot = 0

    return np.array([x, vx, np.cos(self.theta), np.sin(self.theta), theta_dot])


class InvertedPendulumSwingup(InvertedPendulum):
  swingup = True


class InvertedDoublePendulum(MJCFBasedRobot):

  def __init__(self):
    MJCFBasedRobot.__init__(self, 'inverted_double_pendulum.xml', 'cart', action_dim=1, obs_dim=9)

  def robot_specific_reset(self, bullet_client):
    self._p = bullet_client
    self.pole2 = self.parts["pole2"]
    self.slider = self.jdict["slider"]
    self.j1 = self.jdict["hinge"]
    self.j2 = self.jdict["hinge2"]
    u = self.np_random.uniform(low=-.1, high=.1, size=[2])
    self.j1.reset_current_position(float(u[0]), 0)
    self.j2.reset_current_position(float(u[1]), 0)
    self.j1.set_motor_torque(0)
    self.j2.set_motor_torque(0)

  def apply_action(self, a):
    assert (np.isfinite(a).all())
    self.slider.set_motor_torque(200 * float(np.clip(a[0], -1, +1)))

  def calc_state(self):
    theta, theta_dot = self.j1.current_position()
    gamma, gamma_dot = self.j2.current_position()
    x, vx = self.slider.current_position()
    self.pos_x, _, self.pos_y = self.pole2.pose().xyz()
    assert (np.isfinite(x))
    return np.array([
        x,
        vx,
        self.pos_x,
        np.cos(theta),
        np.sin(theta),
        theta_dot,
        np.cos(gamma),
        np.sin(gamma),
        gamma_dot,
    ])