CAVS: Basic Coasting

This Connected Automated Vehicle (CAV) demo shows coasting behavior using a simple speed threshold. When the vehicle reaches the threshold speed, it coasts to a stop.

import os

import seaborn as sns

import sys
from pathlib import Path

sys.path.insert(0, str(next(p / "demo_scripts" for p in (Path.cwd(), *Path.cwd().parents) if (p / "demo_scripts").is_dir())))

import fastsim as fsim
from plot_utils import plot_speed_by_time, plot_speed_by_dist

sns.set_theme()

SHOW_PLOTS = os.environ.get("SHOW_PLOTS", "true").lower() == "true"
SAVE_FIGS = os.environ.get("SAVE_FIGS", "false").lower() == "true"

Setup¶

Load a vehicle and cycle. The cycle is extended to allow extra time for coasting delays. A copy of the original cycle is kept for comparison.

coast_speed_mps = 20.0

veh = fsim.Vehicle.from_resource("2012_Ford_Fusion.yaml")
veh.set_save_interval(1)

cyc = fsim.Cycle.from_resource("udds.csv")
end_idle_duration_s = cyc.ending_idle_time_s()
cyc = cyc.extend_time(absolute_time_s=120.0, time_fraction=None)
cyc0 = cyc.copy()

Apply Coasting Maneuver¶

Maneuver modifies the cycle based on coasting parameters. Setting coast_start_speed_meters_per_second causes the vehicle to coast to a stop whenever it reaches that speed.

man = fsim.Maneuver.create_from(cyc, veh.copy())
d = man.to_pydict()
d["coast_allow"] = True
d["coast_start_speed_meters_per_second"] = coast_speed_mps
man = fsim.Maneuver.from_pydict(d)

cyc = man.apply_maneuvers()
cyc = cyc.trim_ending_idle(idle_to_keep_s=end_idle_duration_s)

sd = fsim.SimDrive(veh, cyc)
sd.walk()

Results¶

Original cycle speed vs. achieved speed with coasting applied.

if SHOW_PLOTS:
    c0 = cyc0.to_pydict()
    df = sd.to_dataframe()
    plot_speed_by_time(df, c0, title=f"Coasting from {coast_speed_mps} m/s",
                       save_figs=SAVE_FIGS, show_plots=SHOW_PLOTS)
    plot_speed_by_dist(df, c0, title=f"Coasting from {coast_speed_mps} m/s (distance)",
                       save_figs=SAVE_FIGS, show_plots=SHOW_PLOTS)

Source: fastsim/docs/demo_scripts/vehicle_controls/demo_basic_coasting.py