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| import numpy as np | |
| from gym import utils | |
| from gym.envs.mujoco import MuJocoPyEnv | |
| from gym.spaces import Box | |
| def mass_center(model, sim): | |
| mass = np.expand_dims(model.body_mass, 1) | |
| xpos = sim.data.xipos | |
| return (np.sum(mass * xpos, 0) / np.sum(mass))[0] | |
| class HumanoidEnv(MuJocoPyEnv, utils.EzPickle): | |
| metadata = { | |
| "render_modes": [ | |
| "human", | |
| "rgb_array", | |
| "depth_array", | |
| ], | |
| "render_fps": 67, | |
| } | |
| def __init__(self, **kwargs): | |
| observation_space = Box( | |
| low=-np.inf, high=np.inf, shape=(376,), dtype=np.float64 | |
| ) | |
| MuJocoPyEnv.__init__( | |
| self, "humanoid.xml", 5, observation_space=observation_space, **kwargs | |
| ) | |
| utils.EzPickle.__init__(self, **kwargs) | |
| def _get_obs(self): | |
| data = self.sim.data | |
| return np.concatenate( | |
| [ | |
| data.qpos.flat[2:], | |
| data.qvel.flat, | |
| data.cinert.flat, | |
| data.cvel.flat, | |
| data.qfrc_actuator.flat, | |
| data.cfrc_ext.flat, | |
| ] | |
| ) | |
| def step(self, a): | |
| pos_before = mass_center(self.model, self.sim) | |
| self.do_simulation(a, self.frame_skip) | |
| pos_after = mass_center(self.model, self.sim) | |
| alive_bonus = 5.0 | |
| data = self.sim.data | |
| lin_vel_cost = 1.25 * (pos_after - pos_before) / self.dt | |
| quad_ctrl_cost = 0.1 * np.square(data.ctrl).sum() | |
| quad_impact_cost = 0.5e-6 * np.square(data.cfrc_ext).sum() | |
| quad_impact_cost = min(quad_impact_cost, 10) | |
| reward = lin_vel_cost - quad_ctrl_cost - quad_impact_cost + alive_bonus | |
| qpos = self.sim.data.qpos | |
| terminated = bool((qpos[2] < 1.0) or (qpos[2] > 2.0)) | |
| if self.render_mode == "human": | |
| self.render() | |
| return ( | |
| self._get_obs(), | |
| reward, | |
| terminated, | |
| False, | |
| dict( | |
| reward_linvel=lin_vel_cost, | |
| reward_quadctrl=-quad_ctrl_cost, | |
| reward_alive=alive_bonus, | |
| reward_impact=-quad_impact_cost, | |
| ), | |
| ) | |
| def reset_model(self): | |
| c = 0.01 | |
| self.set_state( | |
| self.init_qpos + self.np_random.uniform(low=-c, high=c, size=self.model.nq), | |
| self.init_qvel | |
| + self.np_random.uniform( | |
| low=-c, | |
| high=c, | |
| size=self.model.nv, | |
| ), | |
| ) | |
| return self._get_obs() | |
| def viewer_setup(self): | |
| assert self.viewer is not None | |
| self.viewer.cam.trackbodyid = 1 | |
| self.viewer.cam.distance = self.model.stat.extent * 1.0 | |
| self.viewer.cam.lookat[2] = 2.0 | |
| self.viewer.cam.elevation = -20 | |