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The WorldSID dummy can be equipped with both a pubic and a sacroiliac joint (S-I joint) loadcell. Although a pubic force criterion and the associated injury risk curve are currently available and used in regulation (ECE95, FMVSS214), as of today injury mechanisms, injury criteria, and injury assessment reference values are not available for the sacroiliac joint itself. The aim of this study was to investigate the sacroiliac joint injury mechanism. Three configurations were identified from full-scale car crashes conducted with the WorldSID 50th percentile male where the force passing through the pubis in all three tests was approximately 1500 N while the sacroiliac Fy / Mx peak values were 4500 N / 50 Nm, 2400 N / 130 Nm, and 5300 N / 150 Nm, respectively. These tests were reproduced using a 150 kg guided probe impacting Post Mortem Human Subjects (PMHS) at 8 m/s, 5.4 m/s and 7.5 m/s.

This paper presents a custom integrated circuit (IC) on which circuit functions necessary for “Active Hydraulic Brake (AHB) system” are integrated, and its key component, “Current-to-Digital Converter” for solenoid current measurement. The AHB system, which realizes a seamless brake feeling for Antilock Brake System (ABS) and Regenerative Brake Cooperative Control of Hybrid Vehicle, and the custom IC are installed in the 4th-generation Prius released in 2015. In the AHB system, as linear solenoid valves are used for hydraulic brake pressure control, high-resolution and high-speed sensing of solenoid current with ripple components due to pulse width modulation (PWM) is one of the key technologies. The proposed current-to-digital converter directly samples the drain-source voltage of the sensing DMOS (double-diffused MOSFET) with an analog-to-digital (A/D) converter (ADC) on the IC, and digitizes it.

Non-equilibrium all-atom MD simulations are used to study the traction properties of hydrocarbon fluids. A fluid layer is confined between two solid Fe plates under the constant normal force of 1.0 GPa. Traction simulations are performed by applying a relative sliding motion to the Fe plates. Shear behaviors of nine hydrocarbon fluids are simulated on a sufficiently large film thickness of 6.7 nm, and succeeded in reproducing the order of the experimental traction coefficients. The dynamic mechanism of the momentum transfer on layers of fluid molecules are analyzed focusing on the intermolecular interactions (density profile, orientation factor, pair-correlation function) and intramolecular interactions (intramolecular interaction energy, conformation change of alicyclic ring). In contrast to the case of n-hexane, which shows low traction due to a fragile chain-like interaction, other mechanisms are obtained in the high traction molecules of cyclohexane, dicyclohexyl and santotrac 50.

A silicon micromachined gyroscope (angular rate sensor, yaw rate sensor) and accelerometer for vehicle stability control system is presented. The 5.1mm×4.7mm sensor chip is fabricated with a silicon micromachining process using a SOI (Silicon on Insulator) silicon wafer and a deep reactive ion etching. The sensor chip has a pair of resonators which are mechanically coupled and function as a tuning fork. The resonators are driven by electrostatic force and their movements are detected by capacitively sensing angstrom displacements. This sensor chip works not only as a gyroscope but also as an accelerometer with a single sensor chip. The sensor unit consists of the sensor chip above, a signal processing IC, a microcomputer and an EEPROM. sigma-delta analog-to-digital conversion (sigma-delta ADC) is adopted to realize the digital calibration of sensor properties.

Posterior translation of the tibia with respect to the femur can stretch the posterior cruciate ligament (PCL). Fifteen millimeters of relative displacement between the femur and tibia is known as the Injury Assessment Reference Value (IARV) for the PCL injury. Since the anterior protuberance of the tibial plateau can be the first site of contact when the knee is flexed, the knee bolster is generally designed with an inclined surface so as not to directly load the projection in frontal crashes. It should be noted, however, that the initial flexion angle of the occupant knee can vary among individuals and the knee flexion angle can change due to the occupant motion. The behavior of the tibial protuberance related to the knee flexion angle has not been described yet. The instantaneous angle of the knee joint at the timing of restraining the knee should be known to manage the geometry and functions of knee restraint devices.

Brake squeal is a phenomenon of self-induced vibration of the brake components during braking. There are many kinds of brake squeal cases whose mechanisms require acting on a various number of potential root causes. Brake squeal phenomena can be generally separated into 2 main mode types related to the direction of disc vibration involved: in-plane mode and out-of-plane mode. For out-of-plane mode, a number of existing countermeasures can be potentially applied after characterization of the squeal occurrence condition by direct experiment or simulation analysis[1,2,3,4]. However, as there are many possible mechanisms and root causes for the in-plane modes[5,6,7,8,9,10,11,12,13], it is generally necessary to perform a detailed analysis of the vibration mechanism before implementing a countermeasure.

The research described in this paper focused on improving occupant ride comfort and road holding by suppressing sprung and unsprung vibration using a semi-active suspension system. It has been reported that occupants tend to perceive vertical vibrations in a frequency range between 4 and 8 Hz as uncomfortable (described below as the “mid-frequency range”). Previous research into semi-active suspension system has focused on reducing vibration in this mid-frequency range, as well as close to the sprung resonance frequency of between 1 and 2 Hz. Skyhook damper (SH) control is a typical ride comfort control used to damp vibration close to the sprung resonance frequency. However, since SH control is not capable of damping vibration in the mid-frequency range, the shock absorbers are configured with a lower damping factor. This helps to achieve a good balance between reducing vibration close to the sprung mass resonance and in the mid-frequency range.

Traffic accidents in the United States were analyzed using FARS and NASS data. When classified according to vehicle body type and collision type, fatalities were most common in the case of (1) passenger car to passenger car frontal impacts, (2) passenger car to passenger car side impacts, (3) passenger car to LTV side impacts, (4) passenger car to truck frontal impacts, and (5) passenger car to LTV frontal impacts. Among these collisions, it was clearly confirmed that the occupants of a passenger car have a strong tendency to suffer injury when “the passenger car has a frontal impact with a heavier passenger car,” “the passenger car has a frontal impact with an LTV/SUV, truck,” and “the passenger car is side impacted by an LTV/SUV,” or the like. These examples should be recognized as clear cases of incompatibility. This paper will describe an approach which aim at improving compatibility. However, around 60% of occupants who suffer fatal injuries are not wearing a seat belt.

If a vehicle is left in a humid environment, the coefficient of friction between the brake pads and discs increases, generating a discomforting noise during braking called brake squeal. It is assumed that this increase in the coefficient of friction in a humid environment is the effect of moisture penetrating between the brake friction surfaces. Therefore, this paper analyzes the factors causing coefficient of friction variation with moisture between the friction surfaces by dynamic observation of these surfaces. The observation was achieved by changing the disc materials from cast iron to borosilicate glass. One side of the glass brake disc was pushed onto the brake pad and the sliding surface was observed from the opposite side by a charge coupled device (CCD) camera. First, a preliminary test was carried out in a dry state using two pad materials with different wear properties to select the appropriate pad for observing the friction surfaces.

Approximately 20% of traffic fatalities in United States 2012 were caused by rollover accidents. Mostly injured parts were head, chest, backbone and arms. In order to clarify the injury mechanism of rollover accidents, kinematics of six kinds of Anthropomorphic Test Devices (ATD) and Post Mortem Human Subjects (PMHS) in the rolling compartment, whose body size is 50th percentile male (AM50), were researched by Zhang et al.(2014) using rollover buck testing system. It was clarified from the research that flexibility of the backbone and thoracic vertebra affected to occupant’s kinematics. On the other hand, the kinematics research of body size except AM50 will be needed in order to decrease traffic fatalities. There were few reports about the researches of occupant kinematics using FE models of body sizes except AM50.

Since the regulations of CO2 emissions have been tightened in each country recently, each automotive manufacturer has responded by bringing competitive technologies that maximize efficiency while promoting vehicle electrification such as xEV. Not only the efficiency, we need to meet or exceed occupant performance and comfort expectations. The climate control system expends a large amount of energy to keep a comfortable environment, having a significant impact on fuel consumption and EV driving range. Therefore, many manufacturers try to save energy and improve occupant comfort quickly by using not only the conventional convective heating by HVAC but also the conductive heating to heat the human body directly such as seat and steering wheel heater. In this study, a radiative heater, which is more efficient than a convective heating to warm anterior thigh and shin where a conductive heating cannot warm, was applied to vehicle.

Vehicle Stability Control (VSC) is a system designed to help drivers when skidding or unstable vehicle behavior is about to occur. We have studied the characteristics of VSC in reducing accidents by analyzing accident data statistics in Japan. The results indicate that VSC is effective in reducing single car accidents and head-on collisions with other automobiles. In these accidents, the analysis showed that VSC may be more helpful in reducing a larger number of accidents in the higher speed range where vehicle dynamics plays a greater part. It also showed that VSC may contribute to reducing accidents that result from unstable vehicle behavior. VSC demonstrated more effectiveness in reducing accidents involving lateral & rear impacts than those of frontal impacts, and in reducing accidents on wet & snowy/icy roads than those on dry roads.

The GS 450h that went on sale in 2006 uses a more powerful motor equipped with a new transmission called Two-stage motor speed reduction device to achieve superlative power performance. However, the increase in motor power meant that new technologies had to be developed to stabilize the system. This paper describes a high-speed power balance control technology that maintains a stable power balance even when the motor speed fluctuates sharply due to tire slippage or other factors, as well as a control technology that maintains a stable power balance even as the motor speed changes continuously during shifting.

Because of recent advances in steering control technology, steer-by-wire systems have continued to become more realistic. The principal issue for these steer-by-wire systems is considered to be promoting reliability through the construction of a design concept that can be utilized appropriately by drivers. This paper first describes the flow between the concept and system structure, and proposes a steer-by-wire system with a mechanical backup mechanism as one possibility. This paper also describes an investigation into its potential advantages using an experimental vehicle installed with the proposed system structure. The potential advantages of steer-by-wire are improved vehicle driving performance, vehicle maneuverability, and the feasibility of innovative packaging and design. In order to make improved maneuverability and design innovations compatible, it is critical to achieve steering characteristics that require little maneuvering angle.

Due to the relative high speed and short distance between the door and occupant, side impact presents a challenging task when analyzing the input force from the door to the occupant. The new FMVSS214 Final Rule in 2007 and the new NCAP in 2008 mandated the use of a SID-IIs in the oblique pole impact test and in the rear seat during an MDB side impact test. Therefore, a high-precision measurement and calculation of the three-dimensional dummy kinematics, as well as the interaction of force inside the dummy (internal force) and force exerted from outside the dummy (external force) will help provide efficient evaluation of design requirements for the door trim and supplemental restraint systems that meet legally mandated requirements.

A new active rear steer (ARS) system has been developed. ARS is an electric four wheel steering system controlled by new logic(designed by H∞-μ synthesis) which maintains good control performance even if the vehicle parameters and /or road surface conditions are changed. ARS control is a typical technology to prevent vehicle side -slip in linear region of tire characteristic. This system offers easy control and reduces vehicle behavior of yawing motion before approaching critical limit. By combining ARS and vehicle stability control (VSC), it is possible to support driving precisely from normal driving to excessive driving. This paper describes the details of this new system which has been installed on 1997 model TOYOTA ARISTO for practical use in JAPAN.

Due to new CO2 regulations and increasing demand for improved fuel economy, reducing aerodynamic drag has become more critical. Aerodynamic drag at the rear of the vehicle accounts for approximately 40% of overall aerodynamic drag due to low base pressure in the wake region. Many studies have focused on the wake region structure and shown that drag reduction modifications such as boattailing the rear end and sharpening the rear edges of the vehicle are effective. Despite optimization using such modifications, recent improvements in the aerodynamic drag coefficient (Cd) seem to have plateaued. One reason for this is the fact that vehicle design is oriented toward style and practicality. Hence, maintaining flexibility of design is crucial to the development of further drag reduction modifications. The purpose of this study was to devise a modification to reduce rear drag without imposing additional design restrictions on the upper body.

A Rear Cross Traffic Auto Brake (RCTAB) system has been developed that uses radar sensors to detect vehicles approaching from the right or left at the rear of the driver’s vehicle, and then performs braking control if the system judges that a collision may occur. This system predicts the intersecting course of approaching vehicles and uses the calculated time-to-collision (TTC) to control the timing of automatic braking with the aim of helping prevent unnecessary operation while ensuring system performance.

According to the U.S. National Highway Traffic Safety Administration, 743 pedal cyclists were killed and 48,000 were injured in motor vehicle crashes in 2013. As a novel active safety equipment to mitigate bicyclist crashes, bicyclist Pre-Collision Systems (PCSs) are being developed by many vehicle manufacturers. Therefore, developing equipment for evaluating bicyclist PCS is essential. This paper describes the development of a bicycle carrier for carrying the surrogate bicyclist in bicyclist PCS testing. An analysis on the United States national crash databases and videos from TASI 110 car naturalistic driving database was conducted to determine a set of most common crash scenarios, the motion speed and profile of bicycles. The bicycle carrier was designed to carry or pull the surrogate bicyclist for bicycle PCS evaluation. The carrier is a platform with a 4 wheel differential driving system.

Toyota Motor Corporation has already designed and developed vehicle brake control systems for relatively low speed off-road driving, such as Downhill Assist Control, Hill-start Assist Control and Active Traction Control. Though off-road utility is improved by virtue of these systems, in specific situations actual performance still depends on driving technique since the driver is required to control the accelerator pedal. Toyota has integrated these existing systems, and developed a new driving technology for off-road driving called “Crawl Control.” Crawl Control automatically modulates brake torque and drive torque to help keep the vehicle speed constant and slow. Unskilled drivers can thereby attain improved capabilities in places where high-level driving techniques are required. This system also reduces the effort required to control the accelerator and the brake pedal. This paper presents a new control algorithm for the realization of this Crawl Control system.