L2F: Learning to Fly Simulator

pip install l2f

This repo contains Python bindings for the simulator introduced in Learning to Fly in Seconds.

Please check the example for how to use it.

CUDA

For the CUDA usage please refer to rl-tools/l2f-benchmark

Getting Started

Install UIServer (forwards states to HTML/JS UI) and the foundation-policy (a general quadrotor policy)

pip install l2f ui-server foundation-policy

Run the UIServer

ui-server

Navigate to http://localhost:13337 This is run separately from the client code such that you can keep the browser open, without windows popping up and going away when re-running your code. Also the camera perspective is maintained across runs.

Then run e.g.:

from copy import copy
import numpy as np
import asyncio, websockets, json
import l2f
from l2f import vector8 as vector
from foundation_policy import QuadrotorPolicy

policy = QuadrotorPolicy()
device = l2f.Device()
rng = vector.VectorRng()
env = vector.VectorEnvironment()
ui = l2f.UI()
params = vector.VectorParameters()
state = vector.VectorState()
observation = np.zeros((env.N_ENVIRONMENTS, env.OBSERVATION_DIM), dtype=np.float32)
next_state = vector.VectorState()

vector.initialize_rng(device, rng, 0)
vector.initialize_environment(device, env)
vector.sample_initial_parameters(device, env, params, rng)
vector.sample_initial_state(device, env, params, state, rng)

async def main():
    uri = "ws://localhost:13337/backend"
    async with websockets.connect(uri) as websocket:
        handshake = json.loads(await websocket.recv(uri))
        assert(handshake["channel"] == "handshake")
        namespace = handshake["data"]["namespace"]
        ui.ns = namespace
        ui_message = vector.set_ui_message(device, env, ui)
        parameters_message = vector.set_parameters_message(device, env, params, ui)
        await websocket.send(ui_message)
        await websocket.send(parameters_message)
        policy.reset()
        for _ in range(500):
            vector.observe(device, env, params, state, observation, rng)
            action = policy.evaluate_step(observation[:, :22])
            dts = vector.step(device, env, params, state, action, next_state, rng)
            state.assign(next_state)
            ui_state = copy(state)
            for i, s in enumerate(ui_state.states):
                s.position[0] += i * 0.1 # Spacing for visualization
            state_action_message = vector.set_state_action_message(device, env, params, ui, ui_state, action)
            await websocket.send(state_action_message)
            await asyncio.sleep(dts[-1])

if __name__ == "__main__":
    asyncio.run(main())