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rotor_py_control/examples/gymnasium_basic_usage.py
2024-01-04 12:25:45 -05:00

132 lines
5.0 KiB
Python

import gymnasium as gym
import numpy as np
import matplotlib.pyplot as plt
# For this demonstration, we'll just use the SE3 controller.
from rotorpy.controllers.quadrotor_control import SE3Control
from rotorpy.vehicles.crazyflie_params import quad_params
controller = SE3Control(quad_params)
# Import the QuadrotorEnv gymnasium environment using the following command.
from rotorpy.learning.quadrotor_environments import QuadrotorEnv
# Reward functions can be specified by the user, or we can import from existing reward functions.
from rotorpy.learning.quadrotor_reward_functions import hover_reward
# First, we need to make the gym environment. The inputs to the model are as follows...
"""
Inputs:
initial_state: the initial state of the quadrotor. The default is hover.
control_mode: the appropriate control abstraction that is used by the controller, options are...
'cmd_motor_speeds': the controller directly commands motor speeds.
'cmd_motor_thrusts': the controller commands forces for each rotor.
'cmd_ctbr': the controller commands a collective thrsut and body rates.
'cmd_ctbm': the controller commands a collective thrust and moments on the x/y/z body axes
'cmd_vel': the controller commands a velocity vector in the body frame.
reward_fn: the reward function, default to hover, but the user can pass in any function that is used as a reward.
quad_params: the parameters for the quadrotor.
max_time: the maximum time of the session.
world: the world for the quadrotor to operate within.
sim_rate: the simulation rate (in Hz), i.e. the timestep.
render_mode: render the quadrotor.
'None': no rendering
'console': output text describing the environment.
'3D': will render the quadrotor in 3D. WARNING: THIS IS SLOW.
"""
env = gym.make("Quadrotor-v0",
control_mode ='cmd_motor_speeds',
reward_fn = hover_reward,
quad_params = quad_params,
max_time = 5,
world = None,
sim_rate = 100,
render_mode='3D',
render_fps=30)
# Now reset the quadrotor.
# Setting initial_state to 'random' will randomly place the vehicle in the map near the origin.
# But you can also set the environment resetting to be deterministic.
observation, info = env.reset(initial_state='random')
# Number of timesteps
T = 300
time = np.arange(T)*(1/100) # Just for plotting purposes.
position = np.zeros((T, 3)) # Just for plotting purposes.
velocity = np.zeros((T, 3)) # Just for plotting purposes.
reward_sum = np.zeros((T,)) # Just for plotting purposes.
actions = np.zeros((T, 4)) # Just for plotting purposes.
for i in range(T):
##### Below is just code for computing the action via the SE3 controller and converting it to an action [-1,1]
# Unpack the observation from the environment
state = {'x': observation[0:3], 'v': observation[3:6], 'q': observation[6:10], 'w': observation[10:13]}
# For illustrative purposes, just command the quad to hover.
flat = {'x': [0, 0, 0],
'x_dot': [0, 0, 0],
'x_ddot': [0, 0, 0],
'x_dddot': [0, 0, 0],
'yaw': 0,
'yaw_dot': 0,
'yaw_ddot': 0}
control_dict = controller.update(0, state, flat)
# Extract the commanded motor speeds.
cmd_motor_speeds = control_dict['cmd_motor_speeds']
# The environment expects the control inputs to all be within the range [-1,1]
action = np.interp(cmd_motor_speeds, [env.unwrapped.rotor_speed_min, env.unwrapped.rotor_speed_max], [-1,1])
###### Alternatively, we could just randomly sample the action space.
# action = np.random.uniform(low=-1, high=1, size=(4,))
# Step forward in the environment
observation, reward, terminated, truncated, info = env.step(action)
# For plotting, save the relevant information
position[i, :] = observation[0:3]
velocity[i, :] = observation[3:6]
if i == 0:
reward_sum[i] = reward
else:
reward_sum[i] = reward_sum[i-1] + reward
actions[i, :] = action
env.close()
# Plotting
(fig, axes) = plt.subplots(nrows=2, ncols=1, num='Quadrotor State')
ax = axes[0]
ax.plot(time, position[:, 0], 'r', label='X')
ax.plot(time, position[:, 1], 'g', label='Y')
ax.plot(time, position[:, 2], 'b', label='Z')
ax.set_ylabel("Position, m")
ax.legend()
ax = axes[1]
ax.plot(time, velocity[:, 0], 'r', label='X')
ax.plot(time, velocity[:, 1], 'g', label='Y')
ax.plot(time, velocity[:, 2], 'b', label='Z')
ax.set_ylabel("Velocity, m/s")
ax.set_xlabel("Time, s")
(fig, axes) = plt.subplots(nrows=2, ncols=1, num="Action and Reward")
ax = axes[0]
ax.plot(time, actions[:, 0], 'r', label='action 1')
ax.plot(time, actions[:, 1], 'g', label='action 2')
ax.plot(time, actions[:, 2], 'b', label='action 3')
ax.plot(time, actions[:, 3], 'm', label='action 4')
ax.set_ylabel("Action")
ax.legend()
ax = axes[1]
ax.plot(time, reward_sum, 'k')
ax.set_xlabel("Time, s")
ax.set_ylabel("Reward Sum")
plt.show()