Entry Points
The standard entry points are the Modelica models in BobLib.Experiments.Standards. BobSim workflows and direct OpenModelica runs both start from them.
| Model | Use it for | BobSim studies |
|---|---|---|
VehicleSim | Full-vehicle maneuver simulation | RampSteerEval, SteadyStateEval, TransientEval |
FourPostSim | Suspension and chassis response in heave and roll | FourPostEval |
VehicleFMI | FMI export, driver-in-the-loop, and software-in-the-loop work | None |
VehicleSim
VehicleSim is the main maneuver simulation. It follows the VehicleInterfaces demo-style assembly and inserts BobLib physics through subsystem redeclares. See Static Vehicle Templates for the template stack.
The vehicle-level assembly contains:
| Subsystem | Default model |
|---|---|
| Road | VehicleInterfaces.Roads.FlatRoad |
| Atmosphere | BobLib.Atmospheres.ConstantAtmosphere |
| Driver environment | BobLib.DriverEnvironments.Internal.Driver |
| Chassis and suspension | BobLib.Chassis.Chassis_DW with bellcrank double-wishbone axles and stabilizer bars |
| Brakes | BobLib.Chassis.Brakes.BasicVCUBrakes |
| Aero | BobLib.Aero.CFDAeroMap |
| Battery | BobLib.EnergyStorage.BatteryPack |
| VCU | BobLib.Controllers.StandardVCU |
| Inverter | BobLib.PowerElectronics.InverterDC |
| Motor | BobLib.ElectricDrives.Motor |
| Transmission | BobLib.Transmissions.FixedRatioTransmission |
| Driveline | BobLib.Drivelines.RearFinalDriveDifferential |
| World | Modelica.Mechanics.MultiBody.World |
Subsystems share signals through one VehicleInterfaces controlBus and the BobLib AtmosphereBus. See Control Bus.
Maneuver modes
Set the maneuver with vcu.useMode on StandardVCU:
vcu.useMode | Maneuver |
|---|---|
0 | Open-loop ramp steer (default) |
1 | Open-loop sinusoidal steer |
2 | Step steer |
3 | Closed-loop steady-state lateral acceleration |
In mode 3, the VCU ramps vcu.targetAy and drives measured accY to that target with a handwheel-angle PI controller. The VCU speed controller holds longitudinal speed.
Outputs
| Group | Variables |
|---|---|
| Motion | velX, velY, accX, accY, yawVel, roll, sideslip |
| Steering | handwheelAngle, handwheelTorque, steerExcess, leftSteerAngle, rightSteerAngle |
| Tire loads | Fz_FL, Fz_FR, Fz_RL, Fz_RR |
Tire transients
The standard chassis models redeclare the MF52 slip model of all four tires to:
BobLib.Chassis.Suspension.Tires.MF52.SlipModel.TransientSlipThe transient slip model reads relaxation parameters from the tire model records pVehicle.pFrTireModel.relaxation and pVehicle.pRrTireModel.relaxation. Their type is:
BobLib.Records.VehicleRecord.Chassis.Suspension.Templates.Tire.MF52.RelaxationRecordIf the relaxation coefficients are not populated, the model falls back to default longitudinal and lateral relaxation lengths.
Animation and batch runs
The standard models declare:
inner parameter Boolean headless = falseWith the default, OMEdit shows MultiBody animation geometry. Set headless = true for batch or CI runs that do not need it.
FourPostSim
FourPostSim isolates suspension and chassis response for heave and roll sweeps. It extends a four-post architecture template. Its outputs are two FourPostEvalRecord instances, frKnC and rrKnC, which hold K&C-style response data for the front and rear axles.
VehicleFMI
VehicleFMI is a full vehicle whose only public inputs are the driver commands: steering-wheel angle, accelerator pedal, and brake pedal. The VCU and EV plant stay inside the model. Use it when an external source owns the driver commands, such as an FMI host, a driver-in-the-loop rig, or early software-in-the-loop work.