Main Content

Virtual Vehicle Concepts and Terminology

The Virtual Vehicle Composer app uses terminology from several technical disciplines. Refer to this table to understand key terminology and concepts in the app.

Center of mass (CM)The point at the mean position of the mass in a body or systemApplying a single force to the center of mass produces no angular acceleration of the body
ComponentA self-contained element of the virtual vehicle, with ports and internal computations compatible with the model template


  • A physical vehicle component, like a tire

  • A physical vehicle system or subsystem, like a suspension system

  • A control system in the vehicle, like an anti-lock braking system

  • A driver model

  • Environmental conditions

Custom catalogAn XML file that serves as a directory pointing to custom componentsOnce added to the custom catalog, these components appear in their corresponding drop-down lists
Custom componentA user-customized instance of a component


  • A component created inside Virtual Vehicle Composer by reparameterizing it, then saved to the custom catalog

  • A Simulink model that is created outside the Virtual Vehicle Composer and imported to the custom catalog

Degree of freedom (DOF)A direction of translation or rotation of the vehicle that the vehicle model includesStraight-line motion is one-DOF dynamics, motion in a plane is three-DOF dynamics, and motion in space is six-DOF dynamics

Earth-fixed coordinate system

Right-hand system (XE, YE, ZE) with directions relative to a fixed inertial reference

Direction senses:

  • XE — Horizontal, normal to gravitational vector

  • YE — Horizontal, normal to gravitational vector and XE

  • ZE — Vertical, positive downward, parallel to gravitational vector

Simulink model template

Simulink model architecture that accommodates physical Simulink blocks

Physical block sources:

  • Powertrain Blockset™

  • Vehicle Dynamics Blockset™

Simscape model template

Simulink model architecture that accommodates physical Simscape blocks

Physical block sources:

  • Simscape™

  • Simscape Driveline™

  • Simscape Electrical™

  • Simscape Fluids™

  • Simscape Multibody™ Link

Sprung mass

Mass of vehicle, omitting tires and wheels

Includes mass of components such as batteries, electric motors, and driveline components

Sprung mass CM location

Location in terms of vehicle references

Location parameters:

  • Longitudinal distance from rear axle

  • Lateral distance to the right of the vehicle centerline

  • Vertical distance upward from axle plane

Translational motionMotion in space of the center of massThe app describes translation in terms of one or more coordinate systems.
Vehicle coordinate system

Right-handed system (XV, YV, ZV) with directions relative to the vehicle body

Direction senses:

  • XV — Longitudinal, positive forward along vehicle centerline

  • YV — Lateral, positive rightward in vehicle plane, perpendicular to the vehicle centerline

  • ZV — Vertical, positive downward and perpendicular to the XV- and YV-axes

World coordinate system

Left-hand system (XW, YW, ZW) with the ground plane fixed relative to the earth-fixed coordinate system

Direction senses:

  • XW — Positive along vehicle centerline, in the horizontal ground plane

  • YW — Positive to the right, perpendicular to XW, in the ground plane

  • ZW — Vertical, positive upward, opposite the gravitational vector

See Also

Related Examples

More About