Richard Romano

The Iowa Driving Simulator: an immersive research environment

This simulators rich, fully interactive environment provides varied scenarios for meeting experimental needs-for example, engineering evaluation of automated highway systems. >

THE IOWA DRIVING SIMULATOR : AN IMPLEMENTATION AND APPLICATION OVERVIEW

This paper gives an overview of the Iowa Driving Simulator (IDS) designed to create high fidelity, operator-in-the-loop vehicle simulation and realistic cueing feedback to the driver. The paper refers to a number of human factors issues that are currently being investigated. Focus is on two specific applications of the IDS: a study of Automated Highway Systems (AHS) and vehicle virtual prototyping on a virtual proving ground.

Real-time multi-body vehicle dynamics using a modular modeling methodology

Simulations of ground vehicles are extensively used by military and commercial vehicle developers to aid in the design process. In the past, ground vehicle simulations have focused on non-real-time models. However with the advancement of computers and modeling methodologies, real-time multi-body models have become one of the standard tools used by vehicle developers. Multi-body models are composed of joint, body, and force elements which map well into a modular modeling approach. Based on recursive techniques a set of reusable components were developed for use in a graphical simulation and modeling environment. The components were then connected to form a real-time multi-body model of a Ford Taurus. Finally, the Taurus model was integrated with simulator cueing subsystems to build a complete driving simulator. The performance of the Taurus model was compared with test data. It was found that the vehicle model was both accurate and ran much faster than real-time. Due to the model formulation, the current set of modular components are limited to modeling open treed systems with either a fixed or mobile base body.

High-Frequency Terrain Content and Surface Interactions for Off-Road Simulations

Standard visual database modeling practices in driving simulation reduce geometric complexity of terrain surfaces by using texture maps to simulate high frequency detail. Typically the vehicle dynamics model queries a correlated database that contains the polygons from the high level of detail of the visual database. However the vehicle dynamics database does not contain any of the high frequency information included in the texture maps. To overcome this issue and enhance both the visual and vehicle dynamics databases, a mathematical model of the high frequency content of the ground surface is developed using a set of Non-Uniform Rational B-Splines (NURBS) patches. The patches are combined in the terrain query by superimposing them over the low-frequency polygonal terrain, reintroducing the missing content. The patches are also used to generate Bump Map textures for the image generator so that the visual representation matches the terrain query. An imagery-based approach to generating the mathematical surfaces and Bump Maps from the database’s decal textures is also presented. Future research will include full implementation in a driving simulator. This research was supported by an SBIR Phase I Contract (No. W56HZV-04-C-0101) in conjunction with the U.S. Army TARDEC. BACKGROUND

Realtime Driving Simulation Using A Modular Modeling Methodology

The use of driving simulation in vehicle design and development is growing. For maximal benefit, vehicle models used in the driving simulator must be rapidly reconfigurable and easy to develop. To evaluate potential modeling concepts, vehicle dynamics and vehicle subsystems are developed using modular model components. These are integrated with simulator cueing subsystems, using the same modeling concepts, to build a complete driving simulator. It was found that the vehicle dynamics and the simulator could be reconfigured easily to meet user needs.

An Open Software Architecture for Operator-in-the-Loop Simulator Design and Integration

This paper describes the design and implementation of an open software architecture for operator-in-the-loop simulators to support virtual prototyping applications. This framework provides properties that are critical to the cost-effective design of complex simulators, including uniform software specification techniques, modular design methodologies, enhanced reliability and maintainability, ease of reconfigurability, and reusability of simulator subsystems. The open architecture has already served as a basis for development of the Iowa Driving Simulator (IDS) and will, with further enhancement, be used to support development of tracked vehicle virtual prototyping simulation under support from the Defense Advanced Projects Research Agency (DARPA). The architecture is suitable for general application to the design and integration of a wide variety of simulation systems.

Sustained sensorimotor control as intermittent decisions about prediction errors: computational framework and application to ground vehicle steering

A conceptual and computational framework is proposed for modelling of human sensorimotor control and is exemplified for the sensorimotor task of steering a car. The framework emphasises control intermittency and extends on existing models by suggesting that the nervous system implements intermittent control using a combination of (1) motor primitives, (2) prediction of sensory outcomes of motor actions, and (3) evidence accumulation of prediction errors. It is shown that approximate but useful sensory predictions in the intermittent control context can be constructed without detailed forward models, as a superposition of simple prediction primitives, resembling neurobiologically observed corollary discharges. The proposed mathematical framework allows straightforward extension to intermittent behaviour from existing one-dimensional continuous models in the linear control and ecological psychology traditions. Empirical data from a driving simulator are used in model-fitting analyses to test some of the framework’s main theoretical predictions: it is shown that human steering control, in routine lane-keeping and in a demanding near-limit task, is better described as a sequence of discrete stepwise control adjustments, than as continuous control. Results on the possible roles of sensory prediction in control adjustment amplitudes, and of evidence accumulation mechanisms in control onset timing, show trends that match the theoretical predictions; these warrant further investigation. The results for the accumulation-based model align with other recent literature, in a possibly converging case against the type of threshold mechanisms that are often assumed in existing models of intermittent control.

Motion Base Simulation of a Hybrid-Electric HMMWV for Fuel Economy Measurement

Abstract : This paper describes a human-in-the-loop motion-based simulator which was built to perform controlled fuel economy measurements for both a conventional and hybrid electric HMMWV. The simulator was constructed with a drivers console, visualization system, and audio system all of which were mounted on the motion base simulator. These interface devices were then integrated with a real-time dynamics model of the HMMWV. The HMMWV dynamics model was built using the real-time vehicle modeling tool SimCreator, which, in turn was integrated with two powertrain models implemented with Gamma Technologies GT-Drive product. These two powertrains consisted of a conventional configuration and a series hybrid-electric configuration. These models were then run on four different standard Army fuel consumption courses to replicate tests which had previously been conducted at the proving ground. Experiments were performed for varying speeds with two experienced proving ground drivers. This paper describes the design and implementation of the simulation environment, the execution of the experiment and presents some results measured in the experiment.

Development of a Vehicle Model/Simulation Evaluation Tool

Abstract : As part of the evaluation of vehicle simulation models, a vehicle dynamics engineer typically desires to compare simulation results to test data from actual vehicles and/or results from known, or higher fidelity simulations. Depending on the type of model, several types of tests and/or maneuvers may need to be compared. For military vehicles, there is the additional requirement to run specific types of maneuvers for vehicle model evaluations to ensure that the vehicle complies with procurement requirements. A thorough evaluation will run two different categories of tests/maneuvers. The first category consists of laboratory type tests that include weight distribution, kinematics and compliance, steering ratio, and other static measures. The second category consists of dynamic maneuvers that include handling, drive train, braking, ride, and obstacle types. In this paper, a process for proper evaluation of vehicle simulation models is presented. A method for evaluating simulation results from different simulation programs is also presented.

Validation of Real-Time Multi-Body Vehicle Dynamics Models for Use in Product Design and Acquisition

The United States Research, Development, and Engineering Command’s Tank Automotive Research, Development and Engineering Center (U.S. Army RDECOM-TARDEC) laboratories, in accordance with a Science and Technology Objective (STO), are looking for both real-time and non real-time modeling and simulation methods to advance the capabilities and methodologies used in the Armys Modeling and Simulation areas. Advancing technologies require TARDEC to model new components and vehicles that may be significantly different from prior systems. TARDEC’s ultimate goal is to develop the capability to model and accurately recreate the behaviors of advance technologies that may present themselves in the Armys Transformation and its Future Combat System (FCS) of vehicles in real-time with the soldier-in-the-loop. This paper discusses TARDEC’s effort to accomplish this goal.