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Currently, the three (3) methods for calculating the HIC-value are: 1) direct computation method, 2) utilization of maximization requirement approach developed by Chou and Nyquist, and 3) a partitioning technique. A method which involves the adoption of an optimization approach for HIC calculation is discussed in this study. This optimization technique, which has previously been applied to Boundary Element Method (BEM), employs an improved constrained variable metric method in recursive quadratic programming. This technique was applied to three theoretical and ten experimental acceleration pulses; the results compare extremely well with exact solution and/or other numerical methods. It is concluded that this optimization scheme provides accurate HIC calculations. A study is planned to investigate the feasibility of extending the application of this optimization technique to an integrated trim/foam/sheet metal pillar system for improved interior head impact protection study.

Occupant simulation models have been used to study trends or specific design changes in “typical” accident modes such as frontal, side, rear, and rollover. This paper explores the usage of the Articulated Total Body Program (ATB) as an accident reconstruction tool. The importance of model validation is discussed. Specific areas of concern such as the contact model, force-deflection data, occupant parameters, restraint system models, head/neck loadings, padding, and intrusion are discussed in the context of accident reconstruction.

The Hybrid III dummy is the anthropomorphic test device specified in the federal regulation for occupant protection in frontal impacts. Performance requirements for the Hybrid III neck are defined in Part 572E of the Code of Federal Regulations, based on biomechanical research and development by General Motors. Compliance requires meeting specified corridors for the input to the system and the response of the system. In 1991 and 1992, a collaborative test effort was undertaken by a Task Group of the Dummy Testing Equipment Subcommittee of the SAE Human Biomechanics and Simulation Standards Committee. Ten dummy calibration laboratories participated in this effort. The Hybrid III neck flexion test, as specified by Part 572E, was the focus of this investigation.

Automatic occupant sensing is acknowledged as an important addition to airbag and crash sensing systems. Increased system performance will result by being able to control deployment based on the presence, orientation and behavior of the passenger. This paper examines the theoretical background of using electric fields to obtain the desired information about vehicle occupants and the challenges of implementing with high reliability on a mass production and mass use basis.

While constantly striving to increase the levels of occupant protection, the need to intelligently detect occupancy has been identified. As different systems were considered, a optical based system was selected because of it's reliability and potential for reasonable cost feasibility. This paper describes the system detection philosophy, function, packaging and application. The paper also discusses the potential of the system for out of position sensing and its implications for smart airbag development.

For many years we have supplied both damped and undamped accelerometers to automotive companies for use in their road and crash tests. Here we present results which reconfirm the conformity of damped accelerometers to automotive crash testing.

The continuing increase in the performance of restraint systems has led to a drastic increase in the number of actuator devices. The individual wiring of the igniters becomes more and more problematic through the accompanied large number of plug connections and cables. Along with demands for weight and volume reduction, there are requirements for EMI and short circuit protection to eliminate erroneous deployment and misuse. As a solution, a new multi-protocol dual wire bus system is described that has the capability to supply energy and address multiple peripheral output stages to simultaneously fire any combination of actuators.

Topsy is a modular system designed for occasional measurements of all composite inertial, kinematic, and compliance parameters which appear in today's sophisticated mathematical simulation models. The emphasis in its design is not “production-line” testing, but research: the operator can observe the vehicle's reaction to developing forces; and as insights develop he can modify the test program as he goes along. Test errors are minimized by running all tests under servo control with continuous display of all data and recording of all known error sources, while the operators closely monitor the test and the developing data. The test facility is organized around an “infrastructure” consisting of baseplates, vehicle locating fixtures, scales, hydraulic and pneumatic power sources, interchangeable valve assemblies and actuators, and transducers. These are organized along with specialized devices into the several forms required for the different tests.

The measurement of angular rotation has many applications in crash testing, particularly in tracking the motion of crash dummies. There are currently a few devices for determining angular rotation. These include accelerometer arrays, magnetohydrodynamic (MHD) sensors, potentiometers, and high speed films. However, there are problems associated with all of these methods. Systron Donner has developed a new device called a “Quartz Rate Sensor” or “QRS”. The QRS utilizes a piezoelectric chip which produces a DC voltage proportional to the rate of rotation of the sensor about its sensitive axis. Angular displacement can then be determined from a simple integration. Results of preliminary tests performed at The U.S. Department of Transportation's Vehicle Research and Test Center suggest that the QRS's yield very accurate results.

The moment of inertia of the crankshaft cannot be ignored when analyzing the dynamics of a motorcycle. In this research, the tire friction force (calculated by drag and tire side force) was used as an index of the drive performance. The ratio of roll rate and steering torque (here after referred to as a roll rate gain) was used as an index of the cornering performance, and it was analyzed as the influence of the moment of inertia of a crankshaft on the drive performance as well as cornering performance. As a result, the influence on drive performance and cornering performance by the moment of inertia has been found.

Conventional restraint systems designed to meet US FMVSS standards only have one level of operation. The seat belt imparts a restraint force to the occupant reflective of belt stiffness characteristics and the airbag is either inflated or not inflated. The system is tuned to one crash scenario, typically a 30 mph (48 kph) barrier crash with an unbelted 50th%ile MHIII dummy. Situations involving other occupants, crash speeds or belt usage conditions may result in tradeoffs to maintain acceptable results for all conditions. Currently, there is considerable interest in adaptive restraint systems that can detect various crash conditions and adjust the restraint system to provide increased levels of protection. There is also a great deal of interest in systems that can detect an out of position occupant and adjust the airbag deployment to lessen the possibility of deployment induced injuries.

This paper describes the contribution of simulation to the development of the new Automotive Stability Management System (ASMS) of ITT. The benefits and limitations of simulation especially with respect to experimental testing with prototype vehicles are discussed. The paper will outline how cost and time to market have been reduced by Off-Line Simulation (OLS) and Real-Time Simulation (RTS). During the development of ASMS, new control algorithms were designed and first validated in the laboratory. Simulation has offered an insight into the vehicle dynamics that is difficult to obtain with prototype vehicles. It has been possible to study the interactions of the vehicle control system and vehicle dynamics under all circumstances. Some simulation examples of typical maneuvers are discussed.

This paper describes an easily-installed, programmable, battery-powered, “series servo second steering wheel”. The steering machine is designed to execute any 16384-step steering program with force and velocity capabilities significantly greater than those of the human driver. Its EPROM memory contains sixteen separate programs, which can be programmed to duplicate any steering input with fidelity and repeatability. During the execution of a program, the handwheel is mechanically “grounded” to eliminate driver interference with measurement of steering angles and torques. The program also outputs auxiliary signals that can be used to control vehicle throttle and brakes, data recorders, or other devices. The paper describes the steering machine's design and operation, its measured capabilities, and some of the SAE, ISO, and rollover test protocols for which it is designed.

For the purposes of modeling vehicle response in lateral lane deviation maneuvers, a path follower that utilizes adaptive control has been developed and implemented into vehicle simulation software. The path follower utilizes input-output, model reference adaptive control so that no a priori knowledge of the vehicle system is required. The reference model response is generated by a second order linear dynamic model and represents the desired lateral lane deviation trajectory of the vehicle under the conditions of a single maneuver. The controller utilizes any steering degree of freedom of the vehicle model as the input. Therefore different vehicle model structures can be used without modification of the controller. With its adaptive structure, the vehicle model can be made to follow the desired trajectory by minimizing the error between its trajectory and the trajectory response of the reference model.

In the coming years, higher reductions in the environmental burdens of the car will be achieved through a better design of the automobile. A controversial debate continues to surround the issue of building this environmentally friendly vehicle. Car designers alike anticipate new design guidelines and evaluation tools capable of reaching these environmental goals. Life Cycle Assessment is one of the tools available today with an application to assist the automobile industry with these new design goals. The paper will demonstrate the potential benefits of LCA for the new design guidelines within the automobile industry.

There has been a recent trend toward the use of lifecycle analysis (LCA) as a decision-making tool for the automotive industry. However, the different practitioners' methods and assumptions vary widely, as do the interpretations put on the results. The lack of uniformity has been addressed by such groups as the Society of Environmental Toxicology and Chemistry (SETAC) and the International Organization for Standardization (ISO), but standardization of methodology assures neither meaningful results nor appropriate use of the results. This paper examines the types of analysis that are possible for automobiles, explains possible pitfalls to be avoided, and suggests ways that LCA can be used as part of a rational decision-making procedure. The key to performing a useful analysis is identification of the factors that will actually be used in making the decision. It makes no sense to analyze system energy use in detail if direct financial cost is to be the decision criterion.

The target audience of this paper is assumed to be new product or marketing managers in automotive component supplier companies. In this paper the author presents a new economic valuation model that can be used for establishing and evaluating environmental pricing strategies in the automotive industry. The Environmental Economic Valuation Model (EEVM) concept presented for the first time in this paper will become one of the most important financial analytical tools to the auto industry for environmental “womb-to-tomb” assessments. This paper attempts to help new product managers understand, measure, and control key environmental issues; in product design, new product development, and total life cycle management. The intent of this paper is to help answer this challenging question: How can new product managers establish and evaluate profitable environmental pricing points throughout their product's total life cycle?

In March of 1995, the University of Texas at Austin Center for Electromechanics (UT-CEM) began work on developing active suspension control algorithms for four-wheeled, off-road, rough terrain, vehicles. To serve as a test platform to validate simulations, a four corner test-rig, representing a military HMMWV at one third scale, was designed and fabricated. Multiwheel control algorithms were developed, based on single wheel concepts previously described in SAE publications. The four-wheel test-rig performance compared well with single wheel test-rig performance, showing that the active suspension concepts developed by UT-CEM, which do not require advanced terrain knowledge (i.e., no “look-ahead”), are compatible with full vehicle control.

Researchers at The University of Texas Center for Electromechanics recently completed design, fabrication, and preliminary testing of an Electromagnetic Active Suspension System (EMASS). The EMASS program was sponsored by the United States Army Tank Automotive and Armaments Command Center (TACOM) and the Defense Advanced Research Projects Agency (DARPA). A full scale, single wheel mockup of an M1 tank suspension was chosen for evaluating the EMASS concept. The specific goal of the program was to increase suspension performance so that cross-country terrain could be negotiated at speeds up to 17.9 m/s (40 mph) without subjecting vehicle occupants to greater than 0.5 gee rms. This paper is a companion paper to a previous SAE publication [1] that developed suspension theory and control approaches. This paper focuses on hardware implementation, software implementation, and experimental results.

Real-time simulation of tracked vehicle dynamics demands very efficient modeling of the vehicle track. Multi-body dynamics models which model the response of each track pitch are complete, but require on the order of 100 degrees of freedom to capture lateral track dynamics and an additional 200 degrees of freedom to capture longitudinal (stretching) track dynamics. The sheer size of such models renders them difficult to use for rapid estimates of track response. This paper summarizes an efficient alternative for modeling vehicle tracks, as illustrated herein by a model for longitudinal track dynamics. The present model is a hybrid discrete/continuous model in which the track is modeled as a continuous uniform elastic rod which is kinematically coupled to discrete models for the sprocket, wheels, and rollers. Solution efficiency derives from transforming the dynamic track model to one employing modal coordinates.