bevy_urdf

Import robots from URDF files and run simulation with rapier. Drones are simulated by integrating dynamics model.

API

1. Add Urdf and Stl plugins to bevy app

UrdfPlugin,
StlPlugin,
ObjPlugin,

2. Load robot in your startup systems

fn setup(mut ew_load_robot: EventWriter<LoadRobot>,) {
...
ew_load_robot.send(LoadRobot {
    urdf_path: "robots/flamingo_edu/urdf/Edu_v4.urdf".to_string(),
    mesh_dir: "assets/robots/flamingo_edu/urdf".to_string(),
});
...
}

3. Subscribe to loaded event and emit spawn event

fn start_simulation(
    mut er_robot_loaded: EventReader<RobotLoaded>,
    mut ew_spawn_robot: EventWriter<SpawnRobot>,
    mut state: ResMut<NextState<AppState>>,
) {
    for event in er_robot_loaded.read() {
        ew_spawn_robot.send(SpawnRobot {
            handle: event.handle.clone(),
            mesh_dir: event.mesh_dir.clone(),
            robot_type: RobotType::NotDrone,
        });
        state.set(AppState::Simulation);
    }
}

Events

Read sensors and control motors through events:

#[derive(Event)]
pub struct SensorsRead {
    pub handle: Handle<UrdfAsset>,
    pub transforms: Vec<Transform>,
    pub joint_angles: Vec<f32>,
}

// for ground robots / cars
#[derive(Event)]
pub struct ControlMotors {
    pub handle: Handle<UrdfAsset>,
    pub velocities: Vec<f32>,
}

// for ground drones
#[derive(Event)]
pub struct ControlThrusts {
    pub handle: Handle<UrdfAsset>,
    pub thrusts: Vec<f32>,
}

Limitations

You may need to hand-inspect urdf files to ensure mesh links are relative paths. package:// and links and gazebo nodes are not supported. Drone rotors aren't yet animated.

Examples

cargo run --example quadrotor --release # drone
cargo run --example quadruped --release # robot-dog