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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.

Simulation is a useful tool which can significantly reduce resources invested during product development. Vehicle manufacturers are using simulations to aid in the evaluation of designs and components, including powertrain systems and controllers. These simulations can be made more useful by addressing issues such as flexibility, modularity, and causality. These issues and other aspects involved in the development and use of powertrain system simulations are discussed in this paper, and a case study of a powertrain system model developed in the PCRL using methodologies based on considerations of such issues is presented.

This paper describes a method for measuring and transmitting tire pressure and temperature using solid state temperature and pressure sensors embedded in each tire. Data is transmitted with closely coupled field antennas, one mounted to the wheel rim and the other rigidly mounted in the comer assembly. The sensors are remotely powered by resonating the antenna in the comer assembly at a low frequency. Digitized sensor data is transmitted back to the antenna in the corner assembly. This approach is advantageous for several reasons. The use of low frequency field antennas eliminates the crosstalk with other tires, systems, or vehicles. The vehicle battery powers the system rather than a battery located in the wheel. The system is capable of providing continuous measurement with a high update rate. Finally, the system electronics can be reduced to custom integrated circuits, resulting in components which are small, light weight, and cost competitive.

This study presents an improved paint wear test. It comprises applying a single layer of paint to tread surface by spraying, running the tires on a vehicle for a short distance, assessing the wear rate by measuring the intensities of reflecting lights at various locations, and comparing them with original values. The system uses changes in the gray level of each point on the tread block to determine wear rate. This method permits the wear rate to be quantitatively evaluated with a very high resolution under well-controlled test conditions. A typical example is provided to show wear distribution across shoulder to shoulder of truck tire. Application of the technique makes studies of the effects of wheel alignment and tire on uneven wear possible.

Numerical solutions are presented for the action of an individual tread element on a wet pavement. Complicate tread geometry and time-dependent loading condition are taken into account in the numerical procedure. A new hydrodynamic lubrication approach based on a product method is applied to conduct the study at greatly increased computational efficiency. Extensive simulation study for various geometries was achieved using finite-element method. Results from the study provide quantitative guidelines to tire designer in the search for the optimum pattern of individual tread element on the basis of thin film wet traction.

This paper describes the measurement procedures and results of vehicle tires using a synchronized optical and analog system. The device detects 3D positions, forces, moments, and contact pressures of a tire on the testing machine. The infrared light is captured by a vision sensor and the load cells as well as pressure transducers were recorded by an A/D board. Results from direct measurements, tire force machine (TFM) measurements, and dynamo measurements are presented. Vertical, lateral and fore-aft forces were applied in the TFM, where side slip and lock-up braking force vs. the normal load and yaw angles, and their relation with 3D tire deformations were measured. For the dynamometer testing, free rolling tests were conducted.

With the presentation of this paper on the impact of reuse on recycling, the justifying groundwork will have been laid for the expanded definition of recycling to include reuse as a valid contribution to recyclability calculations. This proposed research will collect data from a statistical sampling from the membership of the Automotive Recyclers Association (ARA). For the first time, statistical data will be available to scientifically determine the impact or effect of reuse on the current definition of recycling. This data is anticipated to establish an expanded view of the automotive recycling market and validate the inclusion of reuse into the currently accepted definition of recycling and recyclability (W. Lange; SAE 950205) and will be presented in a subsequent SAE paper in 1998.

The paper presents experimental modal analysis of a non-rotating tire for two boundary conditions. The tire is excited by a hammer and the responses are measured in tangential and radial direction with accelerometers Mode shapes and frequencies are assessed from the measured frequency response functions. These experimental results are compared with the modes of a theoretical tire ring model, where tire is modeled as a circular beam that is able to deform in radial and tangential direction. The partial differential equation of the tire ring model is solved using the modal expansion method resulting in a modal description of the free tire vibration. The parameters of the model are established from the measured frequencies of the free tire.

For the first time in volume production, supporting welded aluminum structures were used in the chassis area. Metal sheets, extruded sections, longitudinally seam welded pipes and castings were used as semi-finished products. Extensive strength tests, in cooperation with the Design Department and Production, resulted in sophisticated design solutions. In considering matters important to the customer, these solutions were substantiated through numerous examinations which are especially necessary for aluminum.