fastoad.models.performances.mission.segments.registered.ground_speed_change module

Classes for acceleration/deceleration segments.

class fastoad.models.performances.mission.segments.registered.ground_speed_change.GroundSpeedChangeSegment(name: str = '', target: ~fastoad.model_base.flight_point.FlightPoint = <object object>, isa_offset: float = 0.0, propulsion: ~fastoad.model_base.propulsion.IPropulsion = <object object>, polar: ~fastoad.models.performances.mission.polar.Polar = <object object>, polar_modifier: ~fastoad.models.performances.mission.polar_modifier.AbstractPolarModifier = <factory>, reference_area: float = <object object>, time_step: float = 0.1, maximum_CL: float = None, altitude_bounds: tuple = (-500.0, 40000.0), mach_bounds: tuple = (-1e-06, 5.0), interrupt_if_getting_further_from_target: bool = True, engine_setting: ~fastoad.constants.EngineSetting = EngineSetting.CLIMB, thrust_rate: float = 1.0, wheels_friction: float = 0.03)[source]

Bases: AbstractGroundSegment

Computes a flight path segment where aircraft is accelerated or de-accelerated on the ground

The target must define an airspeed (equivalent, true or Mach) value.

get_distance_to_target(flight_points: List[FlightPoint], target: FlightPoint) → float[source]

Computes a “distance” from last flight point to target.

Computed does not need to have a real meaning. The important point is that it must be signed so that algorithm knows on which “side” of the target we are. And of course, it should be 0. if flight point is on target.

Parameters:

  • flight_points – list of all currently computed flight_points

  • target – segment target (will not contain relative values)

Returns:

  1. if target is attained, a non-null value otherwise

CONSTANT_VALUE = 'constant'

Using this value will tell to keep the associated parameter constant.

altitude_bounds: tuple = (-500.0, 40000.0)

Minimum and maximum authorized altitude values. If computed altitude gets beyond these limits, computation will be interrupted and a warning message will be issued in logger.

complete_flight_point(flight_point: FlightPoint)

Computes data for provided flight point.

Assumes that it is already defined for time, altitude, mass, ground distance and speed (TAS, EAS, or Mach).

Parameters:

flight_point – the flight point that will be completed in-place

static complete_flight_point_from(flight_point: FlightPoint, source: FlightPoint)

Sets undefined values in flight_point using the ones from source.

The particular case of speeds is taken into account: if at least one speed parameter is defined, all other speed parameters are considered defined, because they will be deduced when needed.

Parameters:

  • flight_point –

  • source –

compute_from(start: FlightPoint) → DataFrame

Computes the flight path segment from provided start point.

Computation ends when target is attained, or if the computation stops getting closer to target. For instance, a climb computation with too low thrust will only return one flight point, that is the provided start point.

Important

When subclasssing, if you need to overload compute_from(), you should consider overriding compute_from_start_to_target() instead. Therefore, you will take benefit of the preprocessing of start and target flight points that is done in compute_from().

Parameters:

start – the initial flight point, defined for altitude, mass and speed (true_airspeed, equivalent_airspeed or mach). Can also be defined for time and/or ground_distance.

Returns:

a pandas DataFrame where column names match fields of FlightPoint

compute_from_start_to_target(start: FlightPoint, target: FlightPoint) → DataFrame

Here should come the implementation for computing flight points between start and target flight points.

Parameters:

  • start –

  • target – Definition of segment target

Returns:

a pandas DataFrame where column names match fields of FlightPoint

compute_lift(flight_point: FlightPoint, reference_force: float, polar: Polar)

Fills values for CL, and lift in provided flight_point.

Parameters:

  • flight_point –

  • reference_force – CL = lift / reference_force

  • polar – unused here, but can be used when overloading this method

compute_next_flight_point(flight_points: List[FlightPoint], time_step: float) → FlightPoint

Computes time, altitude, speed, mass and ground distance of next flight point.

Parameters:

  • flight_points – previous flight points

  • time_step – time step for computing next point

Returns:

the computed next flight point

compute_propulsion(flight_point: FlightPoint)

Computes propulsion data.

Provided flight point is modified in place.

Generally, this method should end with:

self.propulsion.compute_flight_points(flight_point)
Parameters:

flight_point –

static consume_fuel(flight_point: FlightPoint, previous: FlightPoint, fuel_consumption: float = None, mass_ratio: float = None)

This method should be used whenever fuel consumption has to be stored.

It ensures that “mass” and “consumed_fuel” fields will be kept consistent.

Mass can be modified using the ‘fuel_consumption” argument, or the ‘mass_ratio’ argument. One of them should be provided.

Parameters:

  • flight_point – the FlightPoint instance where “mass” and “consumed_fuel” fields will get new values

  • previous – FlightPoint instance that will be the base for the computation

  • fuel_consumption – consumed fuel, in kg, between ‘previous’ and ‘flight_point’. Positive when fuel is consumed.

  • mass_ratio – the ratio flight_point.mass/previous.mass

engine_setting: EngineSetting = 2

The EngineSetting value associated to the segment. Can be used in the propulsion model.

get_gamma_and_acceleration(flight_point: FlightPoint)

For ground segment, gamma is assumed always 0 and wheel friction (with or without brake) is added to drag

get_next_alpha(previous_point: FlightPoint, time_step: float) → float

Determine the next angle of attack.

Parameters:

  • previous_point – the flight point from which next alpha is computed

  • time_step – the duration between computed flight point and previous_point

interrupt_if_getting_further_from_target: bool = True

If True, computation will be interrupted if a parameter stops getting closer to target between two iterations (which can mean the provided thrust rate is not adapted).

isa_offset: float = 0.0

The temperature offset for ISA atmosphere model.

mach_bounds: tuple = (-1e-06, 5.0)

Minimum and maximum authorized mach values. If computed Mach gets beyond these limits, computation will be interrupted and a warning message will be issued in logger.

maximum_CL: float = None
name: str = ''
polar: Polar = <object object>

The Polar instance that will provide drag data.

propulsion: IPropulsion = <object object>

A IPropulsion instance that will be called at each time step.

reference_area: float = <object object>

The reference area, in m**2.

property target: FlightPoint

The base class of the class hierarchy.

When called, it accepts no arguments and returns a new featureless instance that has no instance attributes and cannot be given any.

thrust_rate: float = 1.0
time_step: float = 0.1

Used time step for computation (actual time step can be lower at some particular times of the flight path).

wheels_friction: float = 0.03
polar_modifier: AbstractPolarModifier