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Assistant Professor
Computer Science Department
University of Iowa
The Iowa Driving Simulator (IDS) is a high-fidelity ground-vehicle simulator incorporating real-time multibody dynamics, high-resolution image generation, audio, six-degree-of-freedom motion, and force feedback in a large parallel and distributed software system. It provides a safe, virtual environment for a variety of driving experiments, including the influence of drugs, disease, and disabilities on driving performance; the effectiveness of computer-assisted driving aids such as collision warning devices and intelligent information systems; and the response of humans to critical events such as sudden, unexpected braking by leading vehicles.
Experimenters using the IDS require scenarios incorporating realistic traffic, pedestrians, stop lights, and variable weather conditions. To elicit natural responses from subjects, situations must seem uncontrived; threatening events such as lane encroachment, sudden deceleration, and vehicles running red lights must occur in the natural course of the simulation without arousing suspicions that would permit subjects to prematurely anticipate upcoming events (e.g. vehicles should not materialize from thin air). The challenge for scenario control is to create complex scenarios that meet experimental needs (e.g. replicability) while maintaining diversity, reactivity, and realism in entity behavior.
In this talk, I will describe the scenario control subsystem of the IDS. I will give an overview of the virtual environment database supporting real-time queries of static and dynamic entities. I will then focus on HCSM, a hierarchical concurrent state machine formalism we use to (1) model the complex, reactive behavior of the dynamic entities and (2) orchestrate scenarios using communication and coordination mechanisms to adaptively direct entity behaviors during simulations. HCSM allows us to to create replicable experimental situations and event sequences that blend smoothly with a background of autonomous, reactive behaviors. I will describe the use of HCSM in IDS as well as in other applications, including the control of simulated human locomotion. Finally, I will describe our current goal (with maybe a few half-baked ideas) of developing an authoring framework for specifying and debugging behaviors and scenarios.
*** This is joint work with Joe Kearney and Yiannis Papelis. ***
Jim Cremer received his Ph.D. from Cornell University in 1989. He remained there until 1992 as a Research Associate in the modeling and simulation group. While at Cornell, Jim led development of the Newton dynamics simulator and, with R. Palmer and R. Zippel, initiated the SimLab project. Since 1992, he has been an Assistant Professor of Computer Science at the University of Iowa. He is currently active in research on scenario control and authoring for virtual environments (in collaboration with Center for Computer Aided Design's Iowa Driving Simulator), interactive dynamics simulation incorporating collision, contact, and control (Isaac), and programming environments for constructing scientific software (SimLab).