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Gillespie, Thomas D.
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ESC Performance of Aftermarket Modified Vehicles: Testing, Simulation, HIL, and the Need for Collaboration

ACEC, LLC-Edmund Browalski
Mechanical Simulation Corporation-Thomas D. Gillespie, Douglas S. Orrin
  • Journal Article
  • 2010-01-2342
Published 2010-10-19 by SAE International in United States
The enactment of FMVSS 126 requires specific safety performance in vehicles 4,536 Kg (10,000 pounds) or less using an Electronic Stability Control (ESC) system as standard equipment by 2011. Further, in 2012, the regulation requires vehicles that have undergone aftermarket modification to remain in compliance with the performance standard. This paper describes: • a brief overview of the standard and its implications • the collaborative approach used in the first successful approach in meeting that requirement by a lift kit manufacturer o a Hardware In the Loop (HIL) test alternative for establishing a reasonable expectation for a vehicle to demonstrate compliance after modification. • Collaborative challenges overcome: o aftermarket manufacturers seeking information sharing with OEMs and Tier One suppliers: o respecting the intellectual property of OEMs and Tier One suppliers o maintaining the integrity between tool competitors and their customers in cross-collaborative efforts
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Model-Based Design of a SUV Anti-rollover Control System

Mechanical Simulation Corporation-Thomas D. Gillespie
The Mathworks, Inc.-Vinod Cherian, Rohit Shenoy, Alec Stothert, Justin Shriver, Jason Ghidella
Published 2008-04-14 by SAE International in United States
This article presents a methodology to apply Model-Based Design to develop and automatically optimize vehicle stability control systems. Such systems are employed to improve the dynamic rollover stability of Sport Utility Vehicles (SUVs). A non-linear vehicle model, representative of a midsize SUV, was built in CarSim®. This vehicle model is used in Simulink® to design a control system that reduces the risk of rollover. Optimization methods are then used to automatically adjust controller parameters to meet the system specifications that ensure the stability of the vehicle. Cosimulation between the two software packages enables rapid design and verification of control algorithms in a virtual environment. The results of the simulation experiments can be visualized through a 3-D animation of vehicle motion. The control system is adapted for the specific vehicle model, enabling it to remain stable under standard test conditions. The National Highway Traffic Safety Administrations' (NHTSA) fishhook maneuver was used to estimate dynamic rollover stability of the vehicle and benchmark the performance of the SUV both with and without the optimized controller.
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Using Vehicle Dynamics Simulation as a Teaching Tool in Automotive Engineering Courses

The University of Michigan-Thomas D. Gillespie
Published 2005-04-11 by SAE International in United States
Some of the best teaching methods are laboratory courses in which students experience application of the principles being presented. Preparing young engineering students for a career in the automotive industry challenges us to provide comparable opportunities to explore the dynamic performance of motor vehicles in a controlled environment.Today we are fortunate to have accurate and easy-to-use software programs making it practical for students to simulate the performance of motor vehicles on “virtual” proving grounds. At the University of Michigan the CarSim® vehicle dynamics simulation program has been introduced as such a tool to augment the learning experience. The software is used in the Automotive Engineering course to supplement homework exercises analyzing acceleration, braking, aerodynamics, and cornering performance. This paper provides an overview of the use of simulation in this setting.
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A Multibody Approach with Graphical User Interface for Simulating Truck Dynamics

Mech. Simulation Corp-Michael W. Sayers
The University of Michigan Transportation Research Institute (UMTRI)-Thomas D. Gillespie
Published 1999-11-15 by SAE International in United States
The use of computer simulation of vehicle dynamics as a development tool has come into its own over the past few decades. “Simulated” testing on a computer makes possible a degree of control and repeatability that allows the automotive engineer to determine the influence of design variables on different aspects of dynamic performance in ways that would be difficult or impossible by experimental methods.One of the software tools receiving wide acceptance for simulating trucks and combination vehicles is Truck-Sim™. The attraction of this program arises in part from its foundation of truck modeling methods developed at the University of Michigan Transportation Research Institute over the past two decades, and the use of an advanced graphical user interface to make the software both easy to understand and easy to use by design and development engineers.The paper provides an overview of the graphical user interface by which the user defines the vehicle and its sub-system properties, the control inputs (maneuvers), and the roadway environment. The interface also provides convenient means to evaluate vehicle performance by means of…
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Characterizing the Road-Damaging Dynamics of Truck Tandem Suspensions

University of Michigan Transportation Research Institute-Thomas D. Gillespie, Steven M. Karamihas
Published 1993-11-01 by SAE International in United States
The road damage caused by heavy trucks is accentuated by the dynamic loads excited by roughness in the road. Simulation models of trucks are used to predict dynamic wheel loads, but special models are required for tandem suspensions. Parameter values to characterize tandem suspension systems can be measured quasi-statically on a suspension measurement facility, but it is not known how well they fit dynamic models.The dynamic behavior of leaf-spring and air-spring tandem suspensions were measured on a hydraulic road simulator using remote parameter characterization techniques. The road simulator tests were duplicated with computer simulations of these suspensions based on quasi-static parameter measurements to compare dynamic load performance. In the case of the walking-beam suspension, simulated performance on the road was compared to experimental test data to evaluate the ability of the walking-beam model to predict dynamic load.The simulation models proved very good at duplicating tandem suspension performance up through axle-hop resonance in the 10-15 Hz range.
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Fundamentals of Vehicle Dynamics

Univ. of Michigan-Ann Arbor-Thomas D. Gillespie
  • Book
  • R-114
Published 1992-02-01 by SAE International in United States
This book attempts to find a middle ground by balancing engineering principles and equations of use to every automotive engineer with practical explanations of the mechanics involved, so that those without a formal engineering degree can still comprehend and use most of the principles discussed. Either as an introductory text or a practical professional overview, this book is an ideal reference.
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A Comparison Of The Dynamic Performance Of A U.S. And A European Heavy Vehicle

Thomas D. Gillespie, Richard Radlinski, Mark Flick
Published 1988-09-01 by SAE International in United States
Despite the general similarity of U.S. and European heavy trucks, there are differences in design properties that affect braking and turning performance. A European tractor-semitrailer was studied for the purpose of comparing its properties to those of U.S. vehicles and assessing the comparative performance. Mass, suspension, and braking system properties of the European tractor and semitrailer were measured in the laboratory and on the proving ground. Turning and braking performance qualities were evaluated by computer simulation and by experimental tests. In turning performance the European combination had a 9 percent advantage in rollover threshold, compared to a generic U.S. vehicle with properties that were in the midrange of U.S. design practice. Higher suspension roll stiffness and higher chassis weight on the European tractor and semitrailer accounted for the higher threshold. The European combination also had a performance advantage in braking when empty due to the use of load-sensing proportioning valves on the tractor and semitrailer. When loaded, however, braking performance of the U.S. combination was superior to that of its European counterpart
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Heavy Truck Ride

Univ. of Michigan-Ann Arbor-Thomas D. Gillespie
  • Special Publication (SP)
  • SP-0607
Published 1985-04-01 by SAE International in United States

The L. Ray Buckendale Lectures, inaugurated in 1954, commemorate the contributions of the 1946 SAE President as a developer of the latent abilities of young men and as an authority in the theory and practice of gearing, particularly as applied to automotive vehicles.

Heavy Truck Ride

University of Michigan-Thomas D. Gillespie
Published 1985-04-01 by SAE International in United States
Designing trucks for good ride characteristics is a challenge to the engineer, given the many design constraints imposed by requirements for transport productivity and efficiency. The objective of this lecture is to explain why trucks ride as they do, and the basic mechanisms involved.The response of primary interest is the vibration to which the driver is exposed in the cab. Whole-body vibration tolerance curves give an indication of how those vibrations are perceived at the seat; however, ride studies have shown that visual and hand/foot vibrations are also important to the perception of ride in trucks.The ride environment of the truck driver is the product of the applied excitation and the response properties of the truck. The major excitation sources are road roughness, the rotating tire/wheel assemblies, the driveline, and the engine. In the low-frequency range the truck's response to these inputs is predictable from rigid-body models of the basic suspension isolation mechanisms, and the pitch-plane tuning to road inputs characterized by "wheelbase filtering." At higher frequencies, the response is influenced by frame bending, cab…