# Copyright © 2021 United States Government as represented by the Administrator of the
# National Aeronautics and Space Administration.  All Rights Reserved.

"""
Example of a DC motor being simulated for a set amount of time, using the single-phase dcmotor model.
"""

import math
from progpy.models import dcmotor_singlephase


def run_example():
    motor = dcmotor_singlephase.DCMotorSP()

    def future_loading(t, x=None):
        f = 0.5

        # Simple load proportional to rotor speed.
        # This is a typical, hyper-simplified model of a fixed-pitch propeller directly attached to the motor shaft such that the resistant torque
        # becomes: Cq * omega^2, where Cq is a (assumed to be) constant depending on the propeller profile and omega is the rotor speed.
        # Since there's no transmission, omega is exactly the speed of the motor shaft.
        if x is None:  # First load (before state is initialized)
            t_l = 0.0
        else:
            t_l = 1e-5 * x["v_rot"] ** 2.0
        return motor.InputContainer(
            {
                "v": 10.0
                + 2.0
                * math.sin(
                    math.tau * f * t
                ),  # voltage input assumed sinusoidal just to show variations in the input. No physical meaning.
                "t_l": t_l,  # assuming constant load (simple)
            }
        )

    simulated_results = motor.simulate_to(
        2.0, future_loading, dt=1e-3, save_freq=0.1, print=True
    )
    simulated_results.states.plot(compact=False)


if __name__ == "__main__":
    print("Simulation of DC single-phase motor")
    run_example()