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An analysis of antilock brake system dynamics, based on nonlinear control theory, was performed. Results were used to define initial performance and design requirements for a prototype fluidic motorcycle antilock system. The analysis emphasized the frequency response of system components and effects on stopping performance and stability. Results showed wheel angular acceleration provides a feasible single loop feedback for antilock control; wheel angular jerk is probably not a desirable primary feedback variable; nominal design requirements for modulator and controller exist that represent a compromise among high and low μ performance, stability, roughness, and signal-to- noise ratio; net time delay between modulator and brake caliper is a key design parameter and should be investigated more thoroughly.

Results of an evaluation of possible advanced brake components and systems for motorcycles are reviewed. Potential improved conventional brake components included: friction materials aimed at improving wet brake performance; and components affecting brake system feel properties. A prototype all-mechanical antilock brake system was evaluated. Results showed improvements in performance may be realized via all three of these areas, based on prototype results that might apply to future designs.

An analytical method applicable to design and development of antilock brake systems is described. Dynamic components of antilock systems --- including vehicle, sensor, and modulator--are examined using nonlinear feedback control techniques. An overall design approach is illustrated via an example involving a motorcycle front brake and typical pneumatic modulator. A computer simulation is used to generate time and frequency responses of system components. These data are used to identify the preferred feedback structure. Results show that a stable antilock limit cycle can exist for wheel angular acceleration feedback, among other possibilities. Overall the method and results can provide additional insight into detailed requirements for antilock components and systems, and may hold potential for reducing development time and costs.

Quantifying the independent effects of vehicle weight and size on overall vehicle safety is necessary in order to assess the risks and benefits of vehicle weight reduction. This paper describes the results of one-stage and two-stage logistic regression analyses of the effects of passenger vehicle weight, wheelbase, track, and footprint on fatalities per accident, accidents per exposure (e.g., vehicle-miles-traveled), and fatalities per exposure using national and multi-state traffic accident and exposure databases. The analyses were accomplished in two phases. The first phase used 1995 though 2000 calendar year data for 1991 through 1999 model year vehicles. The second phase used 2002 through 2008 calendar year data for 2000 through 2007 model year vehicles.

Rider control techniques and the handling qualities of all terrain vehicles (ATVs) are discussed. A manual control view is taken of the rider/vehicle/terrain system, including control inputs to the ATV and perceptual feedbacks to the rider. Steering control, overturning stability, and acceleration limits are considered. The important role of rider body movement is discussed. Comparisons are drawn with motorcycles and off road buggies. Vehicle system requirements that can be important from a design standpoint are reviewed.

This paper summarizes a comprehensive research program of the ride qualities of long-haul trucks. Factors are identified which contribute significantly to differences in ride quality between various truck models and configurations over a range of actual operating conditions. Detailed measurements of six floor and seat accelerations and driver and passenger ride ratings were made on ten in-service trucks over five segments, ranging from “smooth” to “rough,” of a typical California freeway. The experimental methodology is reviewed and validated, and example data and preliminary comparisons between the objective and subjective measures are presented.

Factors involved in improving motorcycle brake systems and components are reviewed. Component and system functional requirements are reviewed from the standpoints of manual control factors, performance, and required operating conditions. Component response properties of example contemporary machines are presented. Results show that, for motorcycle hydraulic disc systems, hysteresis, wet disc response, and other response features related to manual control can be key factors.

Preliminary results of a study to develop lateral-directional handling test procedures for motorcycles are presented. One is a steady-state turn, accomplished with a range of forward speeds and turn radii. The other is a single lane change maneuver, using various degrees of severity and forward speeds. Several example motorcycles were studied analytically and via full scale tests. Data from onboard instrumentation show the effects of vehicle and operational differences on selected response and performance measures. This paper comprises a progress report, and the work is continuing.

A prototype safety analysis system has been developed to assess and forecast vehicle safety that can assist vehicle developers integrate various safety technologies into future production vehicles. The prototype system can be used to assess the actual safety in existing vehicles based on fatal accident and vehicle registration data (e.g., US FARS and Polk data); and to estimate the safety in future vehicles based on the estimated effectiveness of candidate passive and active safety technologies (e.g., Curtain Airbags, CMBS) using a systems model with a representative sample of in-depth accident data (e.g., NASS/CDS). Therefore, the prototype system is a useful tool which can be used to estimate the net overall effectiveness of various candidate safety technologies combined, providing a metric which can be used to help optimize the effectiveness of integrated vehicle safety systems.

An updated evaluation of the effects on predicted injuries of an example crush protective device (CPD) proposed for application to All-Terrain Vehicles (ATVs) is described. As in previous evaluations, this involved extending and applying the test and analysis methods defined in ISO 13232 (2005) for motorcycle impacts, to evaluate the effects of the example CPD in a sample of simulated ATV overturn events. Updated modeling refinements included lowering the energy levels of the simulated overturn events; accounting for potential mechanical/ traumatic (compressive) asphyxia mechanisms; refining and calibrating the force-deflection characteristics of helmet, head, legs and soil so as to reduce potential over-prediction of head and leg injuries; and calibrating the simulation against aggregated injury distributions from actual accidents.

Analytical and experimental studies of the transient and oscillatory behavior of motorcycles are reported. Three example vehicles were used. The effects of adding load, changing operating conditions, and modifying the vehicle configuration are shown. The phenomenon known as cornering weave is illustrated and interpreted.

The Advanced Crash Avoidance Technologies (ACAT) program initiated by the National Highway Traffic Safety Administration had two major overall objectives. These were to develop a standardized Safety Impact Methodology (SIM) tool to evaluate the effectiveness of advanced technologies in avoiding and mitigating specific types of vehicle crashes; and to develop and demonstrate objective tests that are used in the SIM to verify the safety impact of a real system. Honda and Dynamic Research Inc. (DRI) had been developing and applying such SIMs for several years and had a Cooperative Agreement with NHTSA to further develop a SIM in order to determine the feasibility of developing estimates of effectiveness for specific not-yet-deployed safety technologies in the absence of data from real world or field operational tests, and linking it to the results from objective tests.

The Advanced Crash Avoidance Technologies (ACAT) program initiated by the National Highway Safety Administration had two major objectives. These were to develop a standardized Safety Impact Methodology (SIM) tool to evaluate the effectiveness of advanced technologies in avoiding and mitigating specific types of vehicle crashes; and to develop and demonstrate objective tests that are used in the SIM to verify the safety impact of a real system. Honda and Dynamic Research Inc. (DRI) have been developing and applying such SIMs for several years and have a Cooperative Agreement with NHTSA to further develop a SIM that provides an estimate of full systems safety benefits at a national level.

A review, analysis and enumeration are presented of factors relevant to motorcycle airbag feasibility research. This includes: an update of the status of related research in the motorcycle airbag feasibility field; relevant experience and factors from the car airbag field; additional unique factors and considerations for motorcycles; and the potential need to address motorcyclist out-of-position riding; other sizes of riders; motorcycle seating layout variation; resistance to and consequences of unintended deployment on a motorcyclist; neck injury criteria and dummy neck biofidelity; injury risk-benefit considerations; environmental exposure on motorcycles; and discussion of feasibility definition and factors.

A theoretical and experimental investigation of the effects of antilock braking (ALB) on motorcycle braking in a turn (BIT) is described. The analyses involved computer simulation of the dynamic interaction among rider, motorcycle, ALB, and roadway during BIT maneuvers; and instrumented full scale BIT tests with expert and novice riders. The analyses and full scale tests used an example all mechanical, independent front and rear ALB system. The results showed that ALB can help maintain motorcycle stability in straightline and gradual turns at high and excessive brake force levels. In more severe turns, the motorcycle can capsize at low brake force levels, below those which are typically needed to trigger ALB operation. As a consequence, from a fundamental standpoint, contemporary conventional ALB systems cannot be considered to influence or improve motorcycle stability during limit braking in moderate or near limit turns.

A theoretical and empirical view is taken of motorcycle lateral-directional dynamics, handling, and rider control behavior. The analytical development includes equations of motion for the vehicle and a multiple loop feedback model for the control response of the rider/cycle system. Connections with manual control and vehicle response data are shown. The effects of changing fork geometry, operating conditions, and tire lag properties are discussed. Implications are drawn for handling requirements, vehicle design, and rider control techniques.

Motorcycle braking test procedures and results are presented. Both straight line and combined cornering and braking maneuvers were used. Test conditions included various initial speeds, turn radii, surface skid numbers, and levels of braking effort for two instrumented motorcycles. The effect of braking on transient yaw response in turns is demonstrated, also. Overall, the results show that repeatable safety related response and performance measures can be obtained using the prescribed procedures with expert test riders.

Analytical results describing moped lateral-directional response properties are presented. Design characteristics of four example mopeds related to directional handling are presented and compared with sample motorcycle properties. Resultant moped dynamics are quantified and compared. Using a nominal moped example, the sensitivity of the vehicle dynamics to operational and design variables, such as speed, loading and tire properties, is shown. Implications for rider/moped handling are reviewed.

Vehicle safety devices, similar to new pharmaceuticals and medical devices, may be associated with injury risks as well as injury benefits. Available analytical methods from the public health, medical and vehicle safety fields are described. A literature review is provided that includes an overview of relevant principles of risk analysis, risk-benefit terminology, fields of application, types of risk-benefit analysis, methods of quantification, assumptions, data needs, treatment of uncertainties, and risk-benefit criteria. Several applicable quantification methods are further described, including Quality Adjusted Life-Years, Disability Adjusted Life-Years, and Normalized Injury-Fatality Costs. Data input sources are described, including accident sampling and analysis, and paired comparison test and simulation methods.

Results of a study to specify, develop, and test the handling characteristics of a prototype research safety vehicle are reported. Handling requirements which were used to evaluate the transient and steady state response and performance are described. These requirements and criteria were based on a review of contemporary results in the area of handling and controllability, and they combine vehicle performance envelopes and driver-centered considerations. The resulting criteria are used as handling objectives in the testing and evaluation of a prototype small sedan.