# -*- coding: utf-8 -*-
#
# Copyright 2015-2019 European Commission (JRC);
# Licensed under the EUPL (the 'Licence');
# You may not use this work except in compliance with the Licence.
# You may obtain a copy of the Licence at: http://ec.europa.eu/idabc/eupl
"""
Functions and `dsp` model to model the CVT.
"""
import numpy as np
import schedula as sh
from co2mpas.defaults import dfl
dsp = sh.BlueDispatcher(name='CVT model', description='Models the gear box.')
[docs]@sh.add_function(dsp, outputs=['correct_gear'])
def default_correct_gear():
"""
Returns a fake function to correct the gear.
:return:
A function to correct the predicted gear.
:rtype: callable
"""
from .at_gear import CorrectGear
return CorrectGear()
# noinspection PyMissingOrEmptyDocstring,PyPep8Naming,PyUnusedLocal
[docs]class CVT:
[docs] def __init__(self):
# noinspection PyProtectedMember
from ..engine._thermal import _XGBRegressor
self.base_model = _XGBRegressor
self.model = None
[docs] def fit(self, on_engine, gear_box_speeds_in, velocities, accelerations,
gear_box_powers_out):
b = on_engine
X = np.column_stack((velocities, accelerations, gear_box_powers_out))[b]
y = gear_box_speeds_in[b]
# noinspection PyArgumentEqualDefault
self.model = self.base_model(
random_state=0,
max_depth=3,
n_estimators=int(min(300.0, 0.25 * (len(y) - 1))),
objective='reg:squarederror'
)
self.model.fit(X, y)
return self
# noinspection PyUnusedLocal
[docs] @staticmethod
def init_gear(*args, **kwargs):
return lambda *a, **kw: 1
[docs] def predict(self, velocities, accelerations, gear_box_powers_out):
X = np.column_stack((velocities, accelerations, gear_box_powers_out))
return self.model.predict(X)
[docs] def init_speed(self, stop_velocity, gears, velocities, accelerations,
gear_box_powers_out):
predict, x = self.model.predict, np.empty((1, 3), float)
powers = gear_box_powers_out
def _next(i):
x[:, :] = velocities[i], accelerations[i], powers[i]
return predict(x)
return _next
[docs]@sh.add_function(dsp, outputs=['CVT'])
@sh.add_function(
dsp,
inputs=[
'on_engine', 'engine_speeds_out', 'velocities', 'accelerations',
'gear_box_powers_out'
],
outputs=['CVT'], weight=50
)
def calibrate_cvt(
on_engine, gear_box_speeds_in, velocities, accelerations,
gear_box_powers_out):
"""
Calibrates a model for continuously variable transmission (CVT).
:param on_engine:
If the engine is on [-].
:type on_engine: numpy.array
:param gear_box_speeds_in:
Gear box speed [RPM].
:type gear_box_speeds_in: numpy.array
:param velocities:
Vehicle velocity [km/h].
:type velocities: numpy.array
:param accelerations:
Vehicle acceleration [m/s2].
:type accelerations: numpy.array
:param gear_box_powers_out:
Gear box power vector [kW].
:type gear_box_powers_out: numpy.array
:return:
Continuously variable transmission model.
:rtype: callable
"""
model = CVT().fit(
on_engine, gear_box_speeds_in, velocities, accelerations,
gear_box_powers_out
)
return model
dsp.add_data('max_gear', 1)
[docs]@sh.add_function(dsp, outputs=['gears'])
def predict_gears(velocities):
"""
Predicts gear vector [-].
:param velocities:
Vehicle velocity [km/h].
:type velocities: numpy.array
:return:
Gear vector [-].
:rtype: numpy.array
"""
return np.ones_like(velocities, dtype=int)
[docs]@sh.add_function(
dsp,
inputs=['CVT', 'velocities', 'accelerations', 'gear_box_powers_out'],
outputs=['gear_box_speeds_in'],
out_weight={'gear_box_speeds_in': 10}
)
def predict_gear_box_speeds_in(
cvt, velocities, accelerations, gear_box_powers_out):
"""
Predicts gear box speed vector, gear vector, and maximum gear [RPM, -, -].
:param cvt:
Continuously variable transmission model.
:type cvt: callable
:param velocities:
Vehicle velocity [km/h].
:type velocities: numpy.array
:param accelerations:
Vehicle acceleration [m/s2].
:type accelerations: numpy.array
:param gear_box_powers_out:
Gear box power vector [kW].
:type gear_box_powers_out: numpy.array
:return:
Gear box speed vector, gear vector, and maximum gear [RPM, -, -].
:rtype: numpy.array, numpy.array, int
"""
return cvt.predict(velocities, accelerations, gear_box_powers_out)
dsp.add_data('stop_velocity', dfl.values.stop_velocity)
[docs]@sh.add_function(dsp, outputs=['max_speed_velocity_ratio'])
def identify_max_speed_velocity_ratio(
velocities, engine_speeds_out, idle_engine_speed, stop_velocity):
"""
Identifies the maximum speed velocity ratio of the gear box [h*RPM/km].
:param velocities:
Vehicle velocity [km/h].
:type velocities: numpy.array
:param engine_speeds_out:
Engine speed [RPM].
:type engine_speeds_out: numpy.array
:param idle_engine_speed:
Engine speed idle median and std [RPM].
:type idle_engine_speed: (float, float)
:param stop_velocity:
Maximum velocity to consider the vehicle stopped [km/h].
:type stop_velocity: float
:return:
Maximum speed velocity ratio of the gear box [h*RPM/km].
:rtype: float
"""
b = (velocities > stop_velocity)
b &= (engine_speeds_out > idle_engine_speed[0])
return max(engine_speeds_out[b] / velocities[b])
