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.

Term	Definition	Notes
Center of mass (CM)	The point at the mean position of the mass in a body or system	Applying a single force to the center of mass produces no angular acceleration of the body
Component	A self-contained element of the virtual vehicle, with ports and internal computations compatible with the model template	Examples: 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 catalog	An XML file that serves as a directory pointing to custom components	Once added to the custom catalog, these components appear in their corresponding drop-down lists
Custom component	A user-customized instance of a component	Examples: 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 includes	Straight-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 motion	Motion in space of the center of mass	The 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