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GPS Replay

The analysis type GPS Replay allows to compute the energy and power necessary to follow a given GPS track. The GPS track gives the 3D position of the vehicle as a function of time.

In addition to the GPS Replay input file, this analysis needs a valid GPS Track file in GPX format. The relative path of this file must be specified in the GPS Replay input file (see Section 4: gps_file).

The WLTC Class 1 GPS track GPX file can be downloaded here. Note that the GPX file format shall be exactly the one shown in previous file. The current version of the Digital Twin is not tolerant to much variations. Another GPX example can be downloaded.

A python script is available to convert CSV to GPX format compatible with the current version of the digital twin.

The GPS Replay input file must have the following format.

You can download the template file and save it to your workspace. This file correspond to the latest design of eVECTORS. The content of this file is shown hereafter.

##########################
# SECTION 1: Analysis Type
analysis_type: GPS Replay

################################
# SECTION 2: Analysis Parameters
# Finite difference order
# 1 = linear (default)
# 2 = quadratic (not available)
precision order: 1
# Calculation method
# Vector = all forces are calculated in the world CS and are vectors
method: Vector
# Include rotation inertia terms in the energy calculation
# True: rotational inertia terms are take into account
# False: rotational inertia terms are neglected (default)
# The inertia terms are generally small and can be nelected in most cases
Rotation inertia: True

###########################
# SECTION 3: Output Request
# Select output units. Available choices are:
# Energy: J = Joule, kWh = kilo Watt hour
# Power: W = Watt, kW = kilo Watt, HP = Horsepower
# Distance: m = meter, km = kilometer, mile = mile
units:
  Energy: kWh
  Power: kW
  Distance: km
# Would like to save results in a output file? If yes: save:true, If not: save:False
save: True
# Input the output folder where to save the result files
savedire: results
# Input the first part of the output file name.
# The result file name will have following name: "file name"_"trajet"_"GPS track name".yaml
# savename: GPS_Replay_new
# Output details:
# 1 = normal (default)
# 2 = debug
out_level: 2

############################
# SECTION 4: Analysis inputs

# Input the GPS file name and path relative to the workspace folder
gps_file: WLTC-class1.gpx

# Input the vehicle characteristics
vehicle:
  mass: 440 # Total mass of the vehicle + driver + luggage in [kg]
  radius: 0.252 # Wheel radius in [m]
  Cx: 0.325 # Total vehicle aerodynamic drag coefficient [dimensionless]
  Crr: 0.01 # Total vehicule rolling resistance coefficient [dimensionless]
  S: 1.5 # vehicle aerodynamic cross section perpendicular to vehicle velocity in [m^2]
  nbr: 1 # Number of motorized wheel
  V_int: 4 # Total interior volume of the vehicle [m^3]
  S_tot: 10 # Total exterior surface [m^2]

  P_headlight: 80 # Headlight power [W]
  dmdt: 0.05 # Flow rate of air through vents in [kg/s]
  ktherm: 35 # thermal conductivity coefficient in [W/m^2/K]

  I_sun: 000 # Solar heat flux [W/m^2]
  S_windows: 2 # Windows total surface [m^2]
  A_windows: 0.6 # Windows absorption coefficient [dimensionless]
  T_int: 300 # intern temperature [K]
  T_ext: 280 # external temperature [K]

  n_motor: 1 # number of motors [dimensionless]
  efficiency_map: Valeo 415001 # Motor efficiency map. Currently implemented: Valeo 415001

  transmission_ratio: 7.4 # Total transmission ratio between motor pulley and motorised wheel gear [dimensionless]
  eta_battery: 0.95 # Batterie efficiency [dimensionless]
  eta_transmission: 0.96 # transmission axe efficiency [dimensionless]
  eta_motordrive: 0.96 # onduleur efficiency [dimensionless]
  R_int: 0.08 # internal batterie resistance in [ohm]

  Inertia_Mat: # Inertia matrix of the sprung mass, in the vehicle coordinate system [kg.m^2]
    - [1288.14, 0.5, -22.18]
    - [0.5, 2523.19, 1.56]
    - [-22.18, 1.56, 2252.90]
  Wheel_Base: 1.60 # Wheelbase = distance between front and rear axle [m]

  Track: 1.054 # Track = distance between the contact points of the 2 front wheels [m]

  Height: 1.300 # Height of the vehicle [m]

  X_Cog: 1.248 # X coordinate of the vehicle center of gravity, in the vehicle coordinate system [m]

  Y_Cog: 0.045 # Y coordinate of the vehicle center of gravity, in the vehicle coordinate system [m]

  Z_Cog: 0.398 # Z coordinate of the vehicle center of gravity, in the vehicle coordinate system [m]

  Stiff_Front: 10000 # Front suspensions stiffness [N/m]

  Stiff_Rear: 30000 # Rear suspension stiffness [N/m]

  Damp_Front: 450 # Front suspensions damping coefficient [N.s/m]

  Damp_Rear: 600 # Rear suspension damping coefficient [N.s/m]