CarSim Packages

CarSim is software for simulating and analyzing the behavior of four-wheeled vehicles in response to steering, braking, and acceleration inputs. CarSim runs faster than real-time using ordinary PC's. The basic CarSim packages require no other software, although full compatibility with other simulation environments is included for MATLAB/Simulink, LabView, ETAS ASCET, and programming languages such as Visual Basic and C.

Additional packages offer extra capabilities.

CarSim

A basic Windows CarSim package includes the VehicleSim (VS) browser with GUI and database, engineering plotter, animator, and vehicle models.

The vehicle models are provided as dynamically linked libraries (DLL's). The same DLL is used for stand-alone runs (the core vehicle model running with no external software), or with Simulink, or LabView, or ASCET, or custom programs written in C. The DLL always runs at high speed, giving results much faster than real-time on typical PCs. Of course, identical behavior is obtained regardless of the simulation environment, because there is just one DLL used in different contexts.

The basic CarSim license supports four custom DLL's, each with custom equations for a specific combination of suspension types. Four DLL's cover four-wheeled vehicles with these combinations:

• Independent front, Independent rear
• Independent front, solid-axle rear
• Independent front, twist-axle rear
• Solid axle front, solid-axle rear

CarSim Trailer

CarSim Trailer allows eight more solvers to be used, to cover the above four configurations when towing one- and two-axle trailers.

CarSim with Frame Twist

CarSim with frame twist allows alternate DLL's to run with math models that include torsional compliance in the body. The frame twist can be significant for some utility and motorsport vehicles.

CarSim RT & CarSim Trailer RT

CarSim Real-Time (RT) provides math models compiled to run on "target" computers with real-time operating systems such as QNX, Linux RT, dSPACE, etc. A Windows "host" machine is used for the CarSim database, animator, and plotter. Files are automatically sent to and received from the target, where the Hardware-in-the-Loop (HIL) testing is controlled. RT versions are available as off-the-shelf CD's for these platforms:

• dSPACE (DS1005, DS1006, DS1103, MicroAutoBox)
• Opal-RT RT-Lab systems (version 7 and higher)
• National Instruments LabVIEW RT
• Fujitsu-Ten CRAMAS
• A&D (AD5410, AD5440)

Input and output files from CarSim RT can be exchanged with users of offline (Windows, non-RT) CarSim. This lets you follow the same design and evaluation from preliminary design to HIL evaluation.

Driving Simulators (CarSim DS)

CarSim vehicle math models have been used in many driving simulators. Here are several ways to use CarSim in a driving simulator.

• The CarSim DS desktop package includes the basic CarSim software and a license that activates the "live" RT mode of the CarSim animator, plus an RT control that slows the math model down to "wait" for real time, plus a GUI that supports several supported controllers for steering, braking, and shifting the transmission. Options for this package include a higher-quality steering system for more accurate steering feel, and additional live animations for mutiple-screen systems.
• CarSim can be used to replace the math models in existing Windows-based simulator systems. It is often possible to run the regular CarSim math model DLL's from your simulation environment using the VehicleSim API. If not, the CarSim source can be obtained and modified as needed.
• The regular RT systems support live animation and are sometimes uses as driving simulators, especially when the simulator is intended to include HIL controllers.
• CarSim runtime is an option for companies that develop driving simulators. Using CarSim source or RT to get started, the math models can be modified as needed and then a multiple-copy license is arranged with Mechanical Simulation for the customized copies.

CarSim Source

Source code is available for math model equations, to support custom projects such as driving simulators and advanced software projects. All of the source code for the multibody kinematics and dynamics (machine-generated by VehicleSim Lisp, a symbolic multibody program) is provided, along with some of the hand-written library routines for the springs, controllers, etc. A precompiled library file is also provided that provides low-level runtime support for reading input files, processing VS commands, and handling the proprietary 3D VS road model.

Note that you might not need the full source. Even the basic CarSim package comes with limited source that allows you to extend the models using the VehicleSim application program interface (API).

CarSim Information