STISIM Drive Help

STISIM Drive - Introduction

Welcome to the wonderful world of driving simulation. With the purchase of STISIM Drive you have made a commitment to create driving scenarios that mimic real life driving situations but do so in a safe yet realistic environment. STISIM Drive is a personal computer based, interactive driving simulator that allows the driver to control all aspects of driving including the vehicles speed and steering. You as the designer will control what the driver sees and when they see it. Unlike most simulation programs that come with a fixed database that you can not easily manipulate without extensive CAD experience, STISIM Drive allows you to change most aspects of the driving scene with simple ASCII text commands. This frees up your time for designing and building various roadway situations instead of just designing and building a roadway.

STISIM Drive is a product of over three decades of research by Systems Technology, Inc. (STI) on low cost techniques for creating laboratory tasks relevant to the psychomotor and cognitive demands of real world driving. Extensive past research on vehicle dynamics and driver control behavior, driver decision making and divided attention behavior and response to traffic control devices has been applied to the creation of control tasks and cognitive scenarios typical of real world driving. A combination of vehicle dynamics characteristics and compensation for CGI (Computer Generated Imagery) transport delays have been employed to create an appropriate stimulus-response relationship between steering inputs and visual display motions. The composite vehicle dynamics/compensation characteristics have been carefully integrated so that steering sensitivity is appropriate over the full range from rest to top speed, and is not sluggish or oscillatory as is the case with many CGI based driving simulations. Driver relevant vehicle dynamics attributes are easily specified in a parameter file along with other simulator setup characteristics.

Driving tasks and scenarios are easily specified with simple commands listed in an events file. A simple scenario definition language (SDL) has been developed to minimize the effort required to specify experimental designs. The SDL frees the user from having to program visual data bases as is the case with most CGI based simulators. The SDL also simplifies the specification of scenario attributes that relate to driver psychomotor, divided attention and cognitive behavior, and permits the definition of road curvature, elevation, intersections, signal timing, interactive traffic, etc.

There are an infinite number of ways that STISIM Drive can be used. Although we have tried to make the program and documentation as simple to use as possible, we can’t possibly foresee all of the application that it will be used for. Subsequently, the documentation is written as generic as possible so that we can provide you with general ideas on how to use the program and not how to solve specific problems. Therefore, we highly recommend that you become familiar with the simulators configuration options and SDL before you begin creating your simulation environment. We understand that this will be a large undertaking on your part, but for the best possible results in the shortest amount of time, you will need to know what the simulation is capable of doing. In general, there are four basic components that make up the STISIM Drive simulator, the graphics environment, the driver controls, the SDL that controls the scenarios, and the STISIM Drive software that ties it all together.

The graphics environment includes the graphics card that generates the images, the display system that displays the images, and the models that are used so that images can be displayed. Graphics cards are discussed in the hardware section of the help system, but in general STISIM Drive requires a specialized graphics card that uses 3DFx chip sets for generating its fast graphics display. Any graphics display device that can handle a standard VGA graphics input can be used for the actual display device. These include computer monitors, head mounted display devices, projectors and even televisions if a scan converter is used (however resolution is lost with this type of arrangement). Finally, and most importantly, the images that are displayed on the screen are simply rendered versions of polygonal models that have been designed and built, then called into the simulator. Almost every image that you see is created using a combination of polygons, texture maps and shaded colors. A separate graphics package such as 3D Studio or NuGraph is required to build the models that are displayed using the simulator. STISIM Drive comes with a number of models that you can use directly with our SDL, but these may not be sufficient for your application. If this is the case, you will need to build some models on your own. STISIM Drive currently has numerous vehicle models, buildings and road signs.

Before you can actually begin setting up and running a simulation scenario, you must first become familiar with STISIM Drive’s capabilities. This next section lists some of the most interesting tasks that the simulator will allow you to perform, but to really understand the power of STISIM Drive, you will need to learn as much as you can about the simulator's configuration and the SDL. Additionally, you should review the sample events files that are installed during program setup. These can be found in the Projects directory under the STISIM Drive main directory (usually C:\STISIM\Projects). These sample files provide practical examples of how many of the STISIM events work. The following is a list of some of the simulator’s general capabilities:

Wide screen (3 computer systems required), giving the driver a 135 degree field of view
Advanced vehicle dynamics (option sold separately, sounds like a commercial)
Interactive vehicles in all lanes of traffic
Traffic Control Devices (barrels, Jersey barriers, traffic signals, traffic signs, etc.)
Buildings, benches, billboards and other rectangular objects can be created with the 3-D block event
Animated pedestrians and cross traffic can be used to force drivers to maneuver
Left and right hand turns at specified intersections
Divided attention symbols located at the right and left of the display
True rear view mirrors that display the roadway scene behind the driver so that they can see and react to approaching traffic
A "horizontal scrolling bar" speedometer displayed at the bottom of roadway display screen
Average and RMS response measures collected at specific defined intervals
Auditory feedback including user defined files and sound effects (siren, car crash, tire screech)
Joystick (not on Windows NT), Analog, or Optical Encoder Interface support for driver controls and an active steering control system (not on all configurations) that feeds roadway feel back to the driver
Performance index computations
Configurable for driving from either side of the road
English or Metric units can be used when specifying inputs and outputs
"Autopilot mode" for scenario checkout
High resolution graphics modes may be used to reduce dither and aliasing effects, and some display colors can be set manually
Scenario parameters can be defined and saved in external files
Various utility programs and examples are included to help you
Configurable for input and output of digital signals from external devices

Before any simulation can be run, the hardware for your system must be installed and all of the peripheral devices such as monitors and controllers must be connected to their respective interface boards. In order to make these connections, you must become familiar with the hardware that you will be using, and know which hardware device connects to which controller board. If you ordered a complete system including all of the hardware, then the interface cables and computer boards should be clearly marked so that all you will need to do is plug each cable into the corresponding interface board in the computer. If all you ordered was software and a graphics board, you will need to determine what connections need to be made. In any event, you should look at the section on hardware and setup.

During the installation process several shortcuts to STISIM Drive will be installed on your computer system. The first will be installed directly in the start menu that appears when you click on Windows Start button. The second, will be setup on your desktop so that you will have easy access by double clicking on a desktop icon. Finally, the installation will setup a STISIM Drive folder that contains a shortcut to the STISIM Drive program as well as other programs that were installed during the setup process. Any of these options can be used to activate the program. When the program is activated, the initial STISIM Drive screen will be displayed for several seconds and then the program's main window will be displayed. You are now ready to start running simulations.

One aspect of the simulator that everyone looks at is speed. Having a constant update rate (having the individual frames that are displayed to the user occur at the same timing rate) is very important because it creates a more realistic environment, reduces the chance of simulator sickness and provides for better data collection. However, this is one of the more difficult things to control in an interactive simulator. This is generally due to the number and complexity of objects appearing in the roadway scene.

First law of interactive computer simulation:

The more complex you make the display scene, the more disappointing the speed performance will become.

Unfortunately, this rule is a fact of life in the world of real time graphical display scenes, and it is something that you will eventually run into. When this happens you will have to investigate ways to improve the simulator’s performance. Here are some suggestions that may help you speed things up:

Watch the experimenter's screen during simulation runs and pay attention to the frame rate parameter.

It may be impossible to generate the scene you desire. Therefore, unfortunately, you may have to simplify the scene that you want to display.

In scenes where there will be a lot of objects, turn the TREE event off, or at least decrease the tree density.

Avoid using multiple or very long Jersey barriers. They do a good job of eliminating a lane, but the same thing can be down with the barrels.

If it is practical, try using a lower resolution screen mode. If you are using a 1024x768 mode, try a 800x600 or a 640x480 screen mode.

You can also gain some speed up by trimming the size of the screen. This can be accomplished by setting the screen size in the configuration options. By trimming a few lines of resolution off the top, bottom, and sides, you may get enough of a speed increase to make it work.