ARCSIM Vehicle Dynamics Simulation Software

ARCSIM Vehicle Dynamics Simulation Software

A software package called ArcSim has been developed by the Automotive Research Center to demonstrate simulation technologies.

View of ArcSim inputs and outputs

Summary

ArcSim is a free set of integrated computer tools for simulating and analyzing the braking and handling of a 6-axle tractor-semitrailer. The software runs under Windows 9x and Windows NT. It contains a fully functional vehicle dynamics simulation program that can simulate responses to arbitrary (user-defined) steering and braking inputs, on flat or inclined ground surfaces. It also includes a plotter and animator for visualizing outputs, and a preloaded database of vehicle descriptions, control inputs, and simulation runs.

The database initiated in ArcSim contains parameters for a preset combination: the M916A1 6-wheel driver tractor and the M870A2 3-axle semitrailer. The simulation models are parametric. Therefore, you can add new parameters to the built-in database as needed to represent any vehicle made of a 3-axle tractor towing a 3-axle semitrailer.

In addition, the ArcSim database includes output files for runs made "off-line" with research computer programs. All outputs, whether made off-line or made with the included model, can be viewed with the built-in animator and plotter.

Although ArcSim has capabilities for switching between models, parameter sets and inputs, the current version contains a single baseline simulation program, derived from the TruckSim software developed at UMTRI and sold commercially by Mechanical Simulation Corporation. As new models are developed, they can be added to the package by using an exiting menu command.

Features

CarSimEd is a complete simulation package, built on the Simulation Graphical User Interface developed at UMTRI in the early 1990s. It includes three separate simulation programs that are integrated through a common graphical interface, plotter, and animator. The most notable feature of the overall software design is its ease of use. Other features are:

Nonlinear 3D mathematical model with 91 state variables.
Full nonlinear tire model.
Solid-axle suspensions.
Major suspension effects, including a new formulation of the UMTRI spring model.
Detailed steering system model with major compliance effects.
User-specified tire/ground friction, grade, and cross-slope.
Point-and-click simulation graphical user interface and data base.
Includes general-purpose Engineering Plotter (EP).
Includes general-purpose Wire-Frame Animator.

Research Results

Besides being a fully functional simulation environment, ArcSim is a "container" for research results produced in the ARC.

Worst Case Inputs. ArcSim is set up to let you rapidly switch between different steering and braking inputs. But how do you determine the "worst case" inputs? Game theory is applied to create a scenario generator, based on mobility evaluation metrics for worst-case analysis. Combined steering and braking inputs, included in the ArcSim database, cause spectacular vehicle rollover.
Power Train Interactions with Vehicle Dynamics. A research code called PowerSim uses Simulink to integrate an engine model, a drive-line model, and the vehicle dynamics model from ArcSim. The simulation shows interactions between the load transfer that occurs when a vehicle accelerates up a hill, the spinning of wheels (cause the load transfer), and the transfer of torque through the drive line, due to the spinning wheels.
Proper Models. The baseline ArcSim model includes 91 state variables, over two-hundred parameters, and many tables. Are all of them necessary? By examining the power flow in the model components, alternative models that are simpler but still capture the dynamics of interest can be determined. The systematic approach is called a proper model generating algorithm.

Getting ArcSim

System Requirements

Item	Minimum	Recommended
CPU	80386	Pentium Pro/AMD K6
Co-Processor	Required for 386 or 486SX
Operating System	Windows 9x or NT	.
RAM	8 MB	16 MB or more
Hard Disk Space	15 MB	20 MB or more

Download and Installation

To download and install the software, do the following.

Create a folder on your hard drive to contain the compressed installation files.
Download the self-extracting archive file arcsim1.exe (7.34 MB) to the folder you just created.
Run the executable file (arcsim.exe). Extract all of the files into the folder you created.
Delete the file arcsim.exe.
Start the installer program setup.exe.
When prompted, select Full Installation. When the program asks if you want to create a Program Manager group, answer Yes.

The installation files are not used by ArcSim, and can be deleted from your hard drive after installation.

Documentation

You can download the complete reference manual for ArcSim (arcman.pdf 1.73 MB) along with its table of contents (arctoc.pdf 6.62K). The manual is in Adobe Acrobat's Portable Document File (pdf) format which can be read by the Adobe Acrobat Reader. For information about Adobe Acrobat Reader, including free access to the reader software, visit Adobe's web site: Steps to Downloading the Free Acrobat Reader.

Related Software

The following table compares some of the major "xSim" software packages that have recently been developed at The University of Michigan.

	PowerSim	ArcSim	TruckSim	AutoSim
Summary	ArcSim + power train model + SimuLink - TruckSim graphic interface	TruckSim + extensions for power train - most models - subsystem details	Simulation programs + data base + graphical interface + plotter + animator	Code generator for rigid-body models. Used to create ArcSim and TruckSim codes.
Users	ARC Researchers	.ARC researchers, industry engineers, students	Industry engineers	Researchers, model builders
Availability	Internal (ARC)	Free!	Commercial	Commercial
Delivered	Future	1997	1994	1990