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Technical Paper

A New Concept for Occupant Deceleration Control during Vehicle Crashes -Study of the Vehicle Mass Separation Model

In order to minimize occupant injury in a vehicle collision, an approach was attempted to address this issue by optimizing the waveform of the vehicle body deceleration to reduce the maximum deceleration applied to the occupant. A previous study has shown that the mathematical solution to the optimal vehicle deceleration waveform comprised three stages: high deceleration, negative deceleration, and constant deceleration. A kinematic model with separated mass of the vehicle was devised to generate the optimal vehicle deceleration waveform comprising three stages including a one with negative deceleration in the middle. The validity of this model has been confirmed by a mathematical study on a one-dimensional lumped mass model. The optimal vehicle deceleration waveform generated by this method was then validated by a three-dimensional dummy simulation.
Technical Paper

A New Concept for Occupant Deceleration Control in a Crash - Part 2

In order to minimize occupant injury in a vehicle crash, an approach was attempted to address this issue by making the wave form of vehicle body deceleration optimal to lower the maximum value of the occupant deceleration. Prior study shows that the mathematical solutions for the optimal vehicle deceleration wave form feature consisting of three aspects: high deceleration, negative deceleration, and constant deceleration. A kinematical model which has separated mass of the vehicle was devised to generate an optimal vehicle deceleration wave form which consists of three segments including a segment of negative deceleration in the middle. The validity of this model has been certified by a mathematical study by using a one-dimensional lumped mass model. The effectiveness of the optimal vehicle deceleration wave form generated by this method was validated by a simulation with a three-dimensional dummy.
Technical Paper

A New Way of Electrical/Electronic Systems Endurance Testing of Vehicles in a Real World Environment Prior to Production Launch

With the increasing emphasis on Systems Engineering, there is a need to ensure that Electrical/Electronic (E/E) Systems Endurance Testing of vehicles, in a real world environment, prior to Production Launch, is performed in a manner and at a technological level that is commensurate with the high level of electronics and computers in contemporary vehicles. Additionally, validating the design and performance of individual standalone electronic systems and modules “on the bench” does not guarantee that all the permutations and combinations of real-world hardware, software, and driving conditions are taken into account. Traditional Proving Ground (PG) vehicle testing focuses mainly on powertrain durability testing, with only a simple checklist being used by the PG drivers as a reminder to cycle some of the electrical components such as the power window switches, turn signals, etc.
Technical Paper

A new concept for occupant deceleration control in a crash

In order to minimize occupant injury in a vehicle crash, an approach was attempted to address this issue by making the wave form of vehicle body deceleration (deceleration curve) optimal to lower the maximum deceleration value applied to the occupant. A study with a one-dimensional, two-mass model was conducted to the kinetic mechanism between the body deceleration curve and the responding occupant''s motion while finding a mathematical solution for the optimal body deceleration curve. A common feature of the derived mathematical solutions is that they consist of three aspects: high deceleration, low or negative deceleration, and constant deceleration. This was demonstrated by simulation with a three-dimensional dummy. The results show that the response of the dummy closely agrees with that of the one-dimensional, two-mass model, thus proving the adequacy of the mathematical solution, and that occupant injury was reduced.
Technical Paper

Air Bag Loading on In-Position Hybrid III Dummy Neck

The Hybrid III family of dummies is used to estimate the response of an occupant during a crash. One recent area of interest is the response of the neck during air bag loading. The biomechanical response of the Hybrid III dummy's neck was based on inertial loading during crash events, when the dummy is restrained by a seat belt and/or seat back. Contact loading resulting from an air bag was not considered when the Hybrid III dummy was designed. This paper considers the effect of air bag loading on the 5th percentile female Hybrid III dummies. The response of the neck is presented in comparison to currently accepted biomechanical corridors. The Hybrid III dummy neck was designed with primary emphasis on appropriate flexion and extension responses using the corridors proposed by Mertz and Patrick. They formulated the mechanical performance requirements of the neck as the relationship between the moment at the occipital condyles and the rotation of the head relative to the torso.
Technical Paper

Analysis of Factors Influencing Side Impact Compatibility

To examine factors influencing side impact compatibility, as a first step, car-to-car tests were conducted to investigate the effect of sill interaction. As a result, it was found that sill interaction had a less significant effect on side impact performance than reducing the load aligned with the dummy. In addition, a series of Mobile Deformable Barrier (MDB) tests were performed to corroborate the conclusions of the car-to-car tests. Comparison of the results of these MDB tests showed that the effect of reducing loading aligned with the driver dummy is more significant than that of engagement with the target car's sill, which is consistent with the car-to-car test results.
Technical Paper

Development of electrostatic capacity type steering sensor using conductive leather

According to the National Automotive Sampling System Crashworthiness Data System (NASS/CDS) implemented by the US Department of Transportation, there were 10,743 accidents in 2016 that involved departure from the road, and among those accidents there were 12,043 fatalities. Lane departure prevention systems are expected to make a significant contribution to reducing accidents of this kind. Progress is also being made in the development of systems that further advance automation to enable autonomous driving. However, the evolution of these kinds of advanced safety systems is also raising concerns about the possibility that when systems are providing driving assistance, drivers may take their hands off the steering wheel and stop paying attention because they place too much trust in the safety systems.
Journal Article

Development of the Next-Generation Steering System (Development of the Twin Lever Steering for Production Vehicle)

Looking back on steering systems in more than a hundred years that have passed since the introduction of the automobile, it can be seen that original method of controlling cars pulled by animals such as horses was by reins, and early automobiles had a single push-pull bar (tiller steering). That became the steering wheel, and an indirect steering mechanism by rotating up and down caught on. While the steering wheel is the main type of steering system in use today, the team have developed the Twin Lever Steering (TLS) system controlled mainly by bi-articular muscles, making use of advancements in science and technology and bioengineering to develop based on bioengineering considerations as shown in Fig. 1. The objective of that is to establish the ultimate steering operation system for drivers. In the first report, the authors reported on results found by using race-car prototypes as shown in Fig. 2.
Journal Article

Development of the Next-generation Steering System (Development of the Twin Lever Steering System)

With the objective of establishing the ultimate steering operation system for drivers, we developed, based on bioengineering considerations, the Twin Lever Steering (TLS) system which mimicks the bi-articular muscles, as shown in Fig. 1 . The bioengineering advantages are as follows: (1) force can be exerted more easily, (2) the steering can be accomplished quickly, (3) the positioning can be done accurately, and (4) the burden on the driver can be reduced (less fatigue). The advantages of the vehicle in terms of its motion are as follows: (1) the line-traceability is improved, (2) the drift control is improved, (3) the lane-change capability is improved, and (4) the lap time and stability are improved. We would like to report on these advantages of the TLS system from a bioengineering standpoint, and also describe the results of some verification test results obtained from vehicles equipped with this new steering system.
Journal Article

ERRATUM: Study of Reproducibility of Pedal Tracking and Detection Response Task to Assess Driver Distraction

1. On page 111, the authors have described a method to assess driver distraction. In this method, participants maintained a white square size on a forward display by using a game gas pedal of like in car-following situation. The size of the white square is determined by calculating the distance to a virtual lead vehicle. The formulas to correct are used to explain variation of acceleration of the virtual lead vehicle. The authors inadvertently incorporated old formulas they had used previously. In the experiments discussed in the article, the corrected formulas were used. Therefore, there is no change in the results. The following from the article:
Technical Paper

Expansion of Motorized Seatbelt Control that Adjusts to Vehicle Behavior and the Effect of that Expansion

Currently, a number of automobile OEMs have been equipped motorized seatbelt systems with volume-production vehicles. Since the current systems are generally initiated by the activation of the automatic collision brakes, or the brake assist systems; the benefit of those systems is limited solely in pre-crash phase. To enhance the effectiveness of the system, we attempted to develop a motorized seatbelt system which enables to control retracing force according to various situations during driving. The present system enables to accomplish both the occupants' comfort and protection performance throughout their driving from when it is buckled to when unbuckled and stored, or during both routine and sport driving, as well as pre-crash phase. Moreover, it was confirmed that lateral occupants' excursion during driving was reduced by up to 50% with the present system.
Technical Paper

Front Impact Pulse Severity Assessment Methodology

The pulse severities from various vehicle impact tests need to be assessed during the impact structure development and targeting stage to assure that the occupants can meet the injury criteria as required. The conventional method using TTZV (time to zero velocity), TDC (total dynamic crush), and G1/G2 (two stage averaged pulse) is often unable to give a quick and clear answer to the question being raised. A simple numerical tool is developed here to assess the pulse severity with a single parameter in which the severity is expressed as the amount of chest travel under a certain target restraint curve or chest A-D curve. The tool is applied to several front impact vehicle pulses to show the effectiveness. The new method developed here can be used to assess the pulse severity in an easy and objective way along with conventional parameters.
Technical Paper

Improvement of visibility for vulnerable parties in traffic accidents

More than half of fatalities in traffic accidents in Japan are the vulnerable parties in such accidents (pedestrians, motorcycles, bicycles). In most of these accidents, the cause is collision involving automobiles. Therefore, reasoning that early detection of such vulnerable parties would lead to a reduction in accidents, we conducted research on the following three systems: - Honda Night Vision System - For night-time detection of pedestrians using infrared cameras. - Active Headlights - For assuring night-time field of vision by directing illumination in the direction of vehicle travel through lights coupled with steering wheel turn and so on. - Inter-Vehicle Motorcycle-Automobile Communication System (IVCS) - Notifies drivers of each other's presence by providing information through communications systems installed on both vehicles. The results from research on these systems show that their use can be expected to have a positive effect in reducing the occurrence of accidents.
Technical Paper

Investigation on an Injury Criterion Related to Traumatic Brain Injury Primarily Induced by Head Rotation

The high frequency of fatal head injuries is one of the important issues in traffic safety, and Traumatic Brain Injuries (TBIs) without skull fracture account for approximately half of them in both occupant and pedestrian crashes. In order to evaluate vehicle safety performance for TBIs in these crashes using anthropomorphic test dummies (ATDs), a comprehensive injury criterion calculated from the rotational rigid motion of the head is required. While many studies have been conducted to investigate such an injury criterion with a focus on diffuse brain injuries in occupant crashes, there have been only a limited number of studies focusing on pedestrian impacts. The objective of this study is to develop a comprehensive injury criterion based on the rotational rigid body motion of the head suitable for both occupant and pedestrian crashes.
Technical Paper

Kinematics Validation of Age-Specific Restrained 50th Percentile Occupant FE Model in Frontal Impact

Recently, the global increase of elderly vehicle users has become an issue to be considered in the effort of enhancing safety performance of vehicle restraint system. It is thought that an evaluation tool for the system representing properties of age-specific human body will play a major role for that. In previous research, the authors had developed age-specific component finite element (FE) models for the lower limb, lumbar spine, and thorax representing the adult and elderly occupants. However, the models have not been validated in terms of full body kinematics. It is essential for such models to be validated in terms of full body kinematics in order to ensure validity of the results of the assessment of the safety performance of restraint systems. In the present research, the adult and elderly occupant full body FE models were developed by incorporating the lower limb, lumbar spine and thorax of the adult and elderly FE models established in previous research.
Technical Paper

Modification of Vehicle Handling Performance by Four-Wheel Steering System

At past ESV conferences, we have reported on a series of studies on how the driver's control performance is affected by vehicle steering response. These studies showed that a four-wheel steering system can reduce the delay in lateral acceleration response to steering action, which may result in better control performance of the driver. The present report examines the handling performance of an experimental vehicle fitted with a four-wheel steering system under a wider range of operating conditions. The studies were conducted using mathematical models and simulation of the driver-vehicle system, plus road tests. The findings indicate that the four-wheel steering system may provide better vehicle handling performance than a conventional two-wheel steering system. A vehicle incorporating this steering system may exhibit improved accident avoidance capabilities.
Technical Paper

Optimization of Head Impact Waveform to Minimize HIC

To mitigate head impact injuries of vehicle occupants in impact accidents, the FMVSS 201 requires padding of vehicle interior so that under the free-moving-head-form impact, the head injury criterion (HIC) is below the limit. More recently, pedestrian head impact on the vehicle bonnet has been a subject being studied and regulated as requirements to the automobile manufacturers. Over the years, the square wave has been considered as the best waveform for head impacts, although it is impractical to achieve. This paper revisits the head impact topic and challenges the optimality of aiming at the square waveform. It studies several different simple waveforms, with the objective to achieve minimal HIC or minimal crush space required in head-form impacts. With that it is found that many other waveforms can be more efficient and more practical than the square wave, especially for the pedestrian impact.
Technical Paper

Rear-End Collision Velocity Reduction System

In Japan, rear-end collisions occur at higher frequency than many other kinds of traffic accident. The causes of rear-end collisions were therefore investigated. Accident statistics was used to conduct a statistical traffic accident analysis and a questionnaire survey was used to conduct a detailed traffic accident analysis. Simulation was then used to perform an accident analysis on the basis of those studies. The results suggested that many of these accidents were caused by momentary inattention during daily driving. Research was therefore carried out to determine what kind of collision avoidance assist system would be effective for use at such times. Tests were carried out to measure the obstacle avoidance characteristics of drivers using actual cars, and control timing parameters were established. In this process, the warning timing was set so that it would not lose its impact as a warning and also so that it would not interfere with the driver.
Technical Paper

Research of Steering Grasping to Take over Driver from System

Lane departure prevention systems are able to detect imminent departure from the road, allowing the driver to apply control to prevent lane departure. These systems possess enormous potential to reduce the number of accidents resulting from road departure, but their effectiveness is highly reliant on their level of acceptance by drivers. The effectiveness of the systems will depend on when they are providing driving assistance, what level of laxness in terms of maintaining contact with the steering wheel is allowed on the part of the driver, and what level of assistance the system provides. This paper will discuss research on the minimum necessary contact and contact strength with the steering wheel on the part of the driver when a lane departure prevention system is in operation.
Technical Paper

Sensitivities of Suspension Bushings on Vehicle Impact Harshness Performances

In this paper, we study the sensitivity of a vehicle impact harshness (IH) performance to the suspension bushing rates. A mid-sized uni-body SUV is selected for this study, with the acceleration responses at the driver seat track and the steering wheel as objective functions. A sensitivity study is conducted using an ADAMS full vehicle model including a tire model and flexible body structure representation over an IH event. The study resulted in the identification of key bushings that affect the IH performance and its sensitivity to the bushing rates. Based on the results, we came-up with an “optimal” bushing set that minimizes impact harshness, which was subjectively verified to result in significant improvement in IH.