RotorPy Simulation

WARNING

This simulator is community supported and maintained. It may or may not work with current versions of PX4.

See Toolchain Installation for information about the environments and tools supported by the core development team.

RotorPy is a Python-based multirotor simulation environment with aerodynamic wrenches, useful for education and research in estimation, planning, and control for UAVs. It provides stand-alone classes and a Gymnasium environment.

Why Use RotorPy?

RotorPy simulates the aerodynamic forces and moments acting on a multirotor, along with actuator limits, sensor noise, wind, and obstacles. This makes it useful when you want to test estimation, planning, or control algorithms against more realistic vehicle dynamics than a simple point-mass or kinematic simulation.

The Gymnasium interface is useful for reinforcement learning and other Python-based research workflows. It lets you connect policies and learning pipelines to a PX4-controlled multirotor simulation without rewriting them around PX4-specific APIs.

Installation

RotorPy can be installed using pip:

pip install rotorpy[px4]

To install other tagged versions, see pyproject.toml.

Running the Simulation

This example will allow you to control the quadrotor through QGroundControl.

TIP

If instead you want RotorPy to take control of the drone you can pass the autopilot_controller=False argument to the PX4Multirotor constructor when instantiating it. This can be useful to test perception pipelines, since the environment is controlled through RotorPy's own controllers.

First you need to build the SITL binary by setting up the toolchain and running:

make px4_sitl

Then run the PX4 SITL binary with the command:

PX4SIMULATOR=rotorpy PX4_SYS_AUTOSTART=10040 ./build/px4_sitl_default/bin/px4

Start the example/px4_basic_example.py, available here and referenced in the code below:

# test_px4_sitl.py

from rotorpy.environments               import Environment
from rotorpy.trajectories.circular_traj import ThreeDCircularTraj
from rotorpy.vehicles.px4_multirotor    import PX4Multirotor
from rotorpy.vehicles.px4_sihsim_quadx_params import quad_params as sihsim_quadx
from rotorpy.controllers.quadrotor_control import SE3Control
from rotorpy.trajectories.hover_traj    import HoverTraj

import numpy as np

circular_trajectory = ThreeDCircularTraj(radius=np.array([1,1,0]))
hover_trajectory = HoverTraj(x0=np.array([0, 0, 5]))

def main():
    vehicle    = PX4Multirotor(sihsim_quadx, enable_ground=True)
    controller = SE3Control(sihsim_quadx)

    env = Environment(
        vehicle    = vehicle,
        controller = controller,
        trajectory = circular_trajectory,
        sim_rate   = 100,
    )
    results = env.run(
        t_final      = 60,
        use_mocap=False,
        plot_mocap=False,
        plot_estimator=False,
        plot_imu=False,
        plot         = True,
        animate_bool = False,
        verbose      = True,
    )

    print("Done—PX4 SITL ran for", len(results["time"]), "steps")

if __name__ == '__main__':
    main()