EnvelopeSim

EnvelopeSim provides an optional, separate implementation of common vehicle envelope calculations. GGV and YMD maps show up in vehicle dynamics workflows everywhere; this is BobSim's transparent implementation of those ideas, tied to the active BobLib vehicle records.

EnvelopeSim is not the gold standard, the key theory reference, or a replacement for the full Modelica maneuver simulations. It is intended to be sane, readable, and useful when you want quick envelope calculations without running the full high-fidelity StandardSim path.

Envelope tools live under:

_2_EnvelopeSim/

Layout

Path	Role
_2_EnvelopeSim/vehicle_yaml.py	Legacy/shared reduced vehicle input loader
_2_EnvelopeSim/GGV/ggv_config.yml	GGV envelope config
_2_EnvelopeSim/GGV/ggv_generation.py	GGV envelope workflow
_2_EnvelopeSim/YMD/ymd_config.yml	YMD envelope config
_2_EnvelopeSim/YMD/ymd_generation.py	YMD envelope workflow
_2_EnvelopeSim/Build/	Intermediate CSV outputs
_2_EnvelopeSim/results/	Public reports and metrics CSVs

Commands

make envelope-ggv
make envelope-ymd
make envelope-all

Use make envelope-all when you intentionally want the optional envelope artifacts alongside a release baseline.

Shared Vehicle Inputs

EnvelopeSim builds a reduced scalar vehicle model from the active BobLib vehicle data and the latest useful standard-study metrics.

It loads:

• wheelbase and track from suspension wheel-center geometry
• sprung, driver, and unsprung mass data
• center-of-gravity data
• tire coefficients from the active tire template
• aero scalars from the active aero map
• useful four-post metrics when available

If four-post metrics are missing, EnvelopeSim falls back to static front mass fraction for lateral load transfer distribution.

GGV Envelope

Run:

make envelope-ggv

Config:

_2_EnvelopeSim/GGV/ggv_config.yml

Useful outputs:

_2_EnvelopeSim/Build/GGV/ggv_first_principles.csv
_2_EnvelopeSim/Build/GGV/ggv_track_performance_profile.csv
_2_EnvelopeSim/Build/GGV/ggv_track_velocity_profile.csv
_2_EnvelopeSim/results/ggv_report.pdf
_2_EnvelopeSim/results/ggv_report_metrics.csv

Use GGV when you want a quick map of combined longitudinal and lateral capability across speed.

YMD Envelope

Run:

make envelope-ymd

Config:

_2_EnvelopeSim/YMD/ymd_config.yml

Useful outputs:

_2_EnvelopeSim/Build/YMD/ymd_first_principles.csv
_2_EnvelopeSim/Build/YMD/ymd_trim_curve.csv
_2_EnvelopeSim/results/ymd_report.pdf
_2_EnvelopeSim/results/ymd_report_metrics.csv

Use YMD when you want to inspect lateral force and yaw moment behavior across sideslip and steering.

When To Use EnvelopeSim

EnvelopeSim is useful for:

• fast plausibility checks before expensive Modelica sweeps
• comparing tire, aero, and mass assumptions
• seeing limit trends across speed
• producing compact optional artifacts tied to the active vehicle record
• cross-checking whether StandardSim behavior aligns with reduced-order expectations

Use StandardSim when the question depends on time-domain multibody behavior, controller behavior, suspension transient response, or detailed model behavior.

Use BobDyn/BobLib directly when the envelope result points to a model-level issue that needs inspection or debugging.