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This paper reports the development and application of an interval max-plus fault-tolerant control to a seat assembly system. Such systems will undergo a profound change because novel seats for autonomous driving contain expanded safety systems and are more voluminous and heavy. Automated guided vehicles are a promising means of transportation in these systems, but they require dedicated and advanced control systems. This rises new challenges because such an assembly system can dispose both shared resources and redundant elements. This paper presents a fault-tolerant control framework, which allows dealing with systems containing shared resources as well as redundancies. It also overcomes the problem of uncertainties and constraints, which are inevitable in industrial reality. [ABSTRACT FROM AUTHOR]

The reliability of automobile seat angle-adjuster directly affects the safety of automobiles. In order to improve the reliability of automobile seat angle-adjuster, the structure of seat angle-adjuster is optimised by bench test. The bench test of seat angle-adjuster is carried out in the light of the standard of enterprise and the seat angle-adjuster structure is improved based on the experimental results. The finite-element model of seat angle-adjuster is established according to parameters of seat angle-adjuster and the finite-element analysis is presented under the boundary conditions. The validity of finite-element model of seat angle-adjuster is verified by comparing the results of bench test with finite-element analysis. The reliability model of seat angle-adjuster system is established on the basis of relationship of key components. The reliability analysis of seat angle-adjuster is put forward based on stress strength interference model and competing risk theory. These results provide a technical support for the promotion of automobile seat angle-adjuster. [ABSTRACT FROM AUTHOR]

The newly revised national standard GB 13057-2014 'The strength of the seats and their anchorages of passenger vehicles' puts forward higher requirements for occupant protection of passenger car seats in the dynamic test. Simply improving safety performance may increase seat weight. Considering the dual requirements of safety performance and light weight, this article adopted the topology optimisation method and took into account the strength requirements of multiple loading conditions: forward loading and rearward loading, and finally optimised the structure of seat backrest frame. By changing the weight ratio of loading conditions and the topological mass fraction, the optimal material distribution and force transmission paths of seat backrest frame were optimised. At the same time, considering the ergonomics and the strength of the seat fixing points, the structure of seat backrest frame was fully optimised. On the premise of improving the safety performance of the seats (occupant protection), significant weight reduction was also achieved. [ABSTRACT FROM AUTHOR]

In a highly autonomous vehicle (HAV), the rotatable seat is likely to be designed to facilitate ease of communication between the occupants. We hypothesize that the protective effects of current restraint systems vary among different seating configurations and that by using the rotational seat to alter the occupant's orientation in accordance with the direction of impact, occupants will be better protected. Moreover, in HAVs, it's likely that an imminent impact could be detected at a time of 200 ms, or even longer, prior to the initial contact. The availability of this additional time could be used strategically to actively position the occupants into a safer position for impact. Finite element simulations were performed using the THUMS model to test the hypothesis. The simulation results indicated that during a frontal impact, the backward-facing occupant is safer than occupants in other seating orientations. Moreover, 200 ms is sufficient to rotate the occupant by ±45° and ±90° without introducing additional injuries. Finally, the timing of the post-rotation impact also plays a role in injury risk of the rear-facing impact. Further studies are needed to optimize the rotating seat parameters in order to maintain occupant posture and improve crash safety in HAVs. [ABSTRACT FROM AUTHOR]

Objectives: The Insurance Institute for Highway Safety (IIHS) rates automotive seats as good, acceptable, marginal, and poor on their abilities to prevent whiplash injuries during rear-end collisions. The goal of this study was to compare the performance of some good- and poor-rated seats at speed changes below 16 km/h where some whiplash injuries occur.Methods: A BioRID II anthropometric test device (ATD) underwent rear-end collisions from 2 to 14 km/h while seated on one of two Volvo Whiplash Prevention seats (WHIPS), a Saab Active Head Restraint seat (SAHR), or a General Motors High Retention seat (GMHR). The WHIPS and SAHR seats were rated good whereas the GMHR seat was rated poor by the IIHS. The ATD's kinematics, kinetics and three neck injury criteria were evaluated across the range of collision severities.Results: Most of the head and torso kinematics, kinetics and injury criteria exhibited graded responses with increasing collision severities. Only head extension angle remained relatively similar across all speed changes. Differences between the good- and poor-rated seats were most apparent in the upper neck loads and moments, and head retraction for speed changes greater than 6 km/h.Conclusions: The relatively similar occupant responses across all seats could explain the marginal reductions in whiplash injury risk between good- and poor-rated seats in field studies. Further research into the design of anti-whiplash devices is required to better understand the link between occupant response and injury, and to better mitigate the risk of whiplash injuries during rear-end collisions. [ABSTRACT FROM AUTHOR]

Objective: Frontal impact chest protection in European cars has been highlighted as an area where possible improvements could be made. The chest is particularly vulnerable in older occupants whose numbers are forecast to increase significantly in the coming decades. This study aimed to provide some direction to areas for possible improvements in frontal crash chest protection.Methods: Real-world crash injury data were interrogated, focusing on cars with current restraint components. The research examined belted front seat occupants in frontal impacts where airbags, pretensioners, and load limiters were present.Results: The chest was the most often injured body region at Abbreviated Injury Scale (AIS) 2+, 3+, and 4+ injury levels. The rate of AIS 2+ and AIS 3+ chest injuries was highest among elderly occupants and lowest among young occupants, and elderly occupants sustained proportionally more severe chest injuries in low/moderate-speed impacts compared to young and middle-aged occupants. However, it should be noted that rates of AIS 2 chest injury were also significantly higher for middle-aged occupants compared to the young. The front passenger seat was shown to be more often associated with significant chest injury than the driver seat. The higher proportion of elderly female occupants was postulated as a reason for this. Skeletal injury was the most frequent type of AIS 2+ chest injury, and the rate of injury for elderly occupants with such injuries was higher than that for young and middle-aged occupants. With the increase in the number of rib fractures, the risk of pulmonary complications and organ injuries tended to increase. The major cause of chest injury was identified as restraining loads transmitted to the chest via the seat belt. The absence of intrusion in the majority of cases suggests an opportunity for the restraint system to better manage the crash pulse, not only for elderly occupants but for those who are middle-aged as well.Conclusions: This study shows the necessity for safety interventions, through new vehicle crashworthiness systems, to improve chest protection, especially for middle-aged and elderly car occupants. Deployment of appropriate injury risk criteria, use of an appropriate dummy thorax, development of a low-energy restraint test, and the development of more adaptive restraints have been discussed as possible solutions to the problem. [ABSTRACT FROM AUTHOR]

Objective: Previous studies have revealed vulnerability of school-age children and older adults in rear seats in motor vehicle crashes. Detailed information about crashes in which these fatalities occur could help improve vehicle and restraint design.Methods: Police accident reports were obtained for crashes from the Fatality Analysis Reporting System data set. Inclusion criteria were crashes in which there was at least one fatally injured restrained rear seat occupant between the ages of 6 and 12 or 55 and older in a passenger vehicle no older than 10 years at the time of the crash. Reports were reviewed for key crash data. Side impacts were selected for analysis.Results: Thirty-nine side impact crashes met the inclusion criteria, resulting in 46 fatalities of interest. Far-side or nondirect impact cases outnumbered near-side cases by 15-11 for juvenile occupants. Sixty-one percent of occupants were in vehicles with side airbags (SABs), all of which deployed for their position, although torso SABs were only present in 3 cases. Head injuries were present in all juvenile cases with injury data available and older occupants suffered equally from head and torso injuries. Impacts with pickup trucks and heavy trucks made up 31 and 22% of all cases, respectively. Three-quarters of cases were judged as survivable for the fatally injured occupant(s), and 5 of 7 cases deemed unsurvivable involved juvenile decedents. Further, of those deemed survivable, two-thirds had damage comparable in magnitude with the same vehicles in consumer information crash tests, evaluated by photo comparison.Conclusions: Older adults suffered thoracic injuries at a higher rate than older children-who suffered predominately head injuries-and most vehicles did not have torso SABs installed, which could have mitigated thoracic injuries. Side impacts in which younger occupants were killed were more severe than impacts that resulted in the death of an older occupant; however, vehicle damage and intrusion in many fatal impacts for both age cohorts appeared similar to that of consumer information testing. Large pickups and heavy vehicles were the striking vehicle in over half of all fatalities; vehicle designs and crash tests should continue to take this into consideration. This research highlights the need for continued work as the automotive safety community seeks to eliminate fatalities in motor vehicle crashes. [ABSTRACT FROM AUTHOR]

Objective: Road traffic accidents are a global issue and serious threat for public health. Children are at high risk of serious injury or death from motor vehicle crashes. Child safety seats (CSSs) can reduce the risk of death and serious injury in children. This study was done to determine the prevalence of child safety seat use in vehicles and the factors influencing their use in a safe society (Tehran, Iran) in 2015.Methods: In this cross-sectional study, 804 parents with children under 12 years old who owned private cars were questioned in different areas of Tehran. A questionnaire included demographic data, and 2 specific questionnaires were used for families that used a CSS and those did not use a CSS. Univariate and multivariate binary logistic regression analyses were conducted. Crude and adjusted odds ratios (AORs) with 95% confidence intervals (CIs) were calculated. All analyses were carried out using SPSS 21.Results: The prevalence of child safety seat use was 18.7% and was significantly higher among parents with an income greater than 50 million rials/month, parents who received child safety seat recommendations, parents living in the north of Tehran, and fathers with more driving experience. Age, weight, and height of children were also factors that influenced the use of child safety seats. The most common reasons for parents to use child safety seats was awareness about the benefits of this device and fear of harm to the child, and the most common reasons for nonuse were child intolerance while sitting in the seat and cost.Conclusion: The prevalence of child safety seat use in Tehran is very low, and most parents are not aware of the importance of child safety seats. Comprehensive programs, including legislation, law enforcement, public education, and publicity to promote the benefits of using CSSs, in Tehran can be an effective step toward increasing the use of child safety devices. [ABSTRACT FROM AUTHOR]

Objectives: Earlier research has shown that the rear row is safer for occupants in crashes than the front row, but there is evidence that improvements in front seat occupant protection in more recent vehicle model years have reduced the safety advantage of the rear seat versus the front seat. The study objective was to identify factors that contribute to serious and fatal injuries in belted rear seat occupants in frontal crashes in newer model year vehicles. Methods: A case series review of belted rear seat occupants who were seriously injured or killed in frontal crashes was conducted. Occupants in frontal crashes were eligible for inclusion if they were 6 years old or older and belted in the rear of a 2000 or newer model year passenger vehicle within 10 model years of the crash year. Crashes were identified using the 2004-2015 National Automotive Sampling System Crashworthiness Data System (NASS-CDS) and included all eligible occupants with at least one Abbreviated Injury Scale (AIS) 3 or greater injury. Using these same inclusion criteria but split into younger (6 to 12 years) and older (55+ years) cohorts, fatal crashes were identified in the 2014-2015 Fatality Analysis Reporting System (FARS) and then local police jurisdictions were contacted for complete crash records. Results: Detailed case series review was completed for 117 rear seat occupants: 36 with Maximum Abbreviated Injury Scale (MAIS) 3+ injuries in NASS-CDS and 81 fatalities identified in FARS. More than half of the injured and killed rear occupants were more severely injured than front seat occupants in the same crash. Serious chest injury, primarily caused by seat belt loading, was present in 22 of the injured occupants and 17 of the 37 fatalities with documented injuries. Nine injured occupants and 18 fatalities sustained serious head injury, primarily from contact with the vehicle interior or severe intrusion. For fatal cases, 12 crashes were considered unsurvivable due to a complete loss of occupant space. For cases considered survivable, intrusion was not a large contributor to fatality. Discussion: Rear seat occupants sustained serious and fatal injuries due to belt loading in crashes in which front seat occupants survived, suggesting a discrepancy in restraint performance between the front and rear rows. Restraint strategies that reduce loading to the chest should be considered, but there may be potential tradeoffs with increased head excursion, particularly in the absence of rear seat airbags. Any new restraint designs should consider the unique needs of the rear seat environment. [ABSTRACT FROM AUTHOR]

Objective: This study reviews trends in rear-facing direction, top tether use, booster seat use, and seating position for children 12 years or younger among motor vehicle passengers in Indiana.Methods: This is an observational, cross-sectional survey of drivers transporting children 15 years and younger collected at 25 convenience locations randomly selected in Indiana during summers of 2009-2015. Observations were conducted by certified child passenger safety technicians (CPST). As the driver completed a written survey collecting demographic data on the driver, the CPST recorded the child demographic data, vehicle seating location, the type of restraint, direction the car safety seat (CSS) was facing, and use of the CSS harness or safety belt as appropriate. Data were analyzed for infants and toddlers younger than 24 months, children in forward-facing CSS, booster seat use, and seating position for children 12 years or younger.Results: During the study period, 4,876 drivers were queried, and 7,725 children 15 years and younger were observed in motor vehicles. Between 2009 and 2015, 1,115 infants and toddlers (age birth to 23 months) were observed in motor vehicles. For infants <1 year, rear-facing increased from 84% to 91%. During the study years the greatest increase in rear facing was for toddlers age 12-17 months (12-61%). Rear facing for those from 18-23 months did not significantly change. Of the 1,653 vehicles observed with a forward-facing car seat, using either the seat belt system or lower anchors, an average of 27% had the top tether attached. For installations of forward-facing seats using the lower anchor, 66% employed the top tether. Among children age 4-7 years observed booster seat use decreased from 72% to 65% during the observation period. Finally, for vehicle seating position, in our sample, more than 85% of children 12 years or younger were seated in a rear seat vehicle position. Unfortunately, 31% of 8- to 12-year-old children were observed in the front seat.Conclusions: Overall, these trends demonstrate an improvement in child passenger safety practices among Indiana drivers. However, this study illuminates areas to improve child passenger safety, such as rear facing for toddlers 18 to 23 months, increasing top tether use, booster seat use, and an emphasis on rear seat position for children 8 to 12 years. This information can be used by primary care providers and child passenger safety technicians and other child passenger safety advocates to develop counseling points and targeted educational campaigns. [ABSTRACT FROM AUTHOR]

Objective: This study compared biomechanical responses of a normally seated Hybrid III dummy on conventional and all belts to seat (ABTS) seats in 40.2 km/h (25 mph) rear sled tests. It determined the difference in performance with modern (≥2000 MY) seats compared to older (<2000 MY) seats and ABTS seats.Methods: The seats were fixed in a sled buck subjected to a 40.2 km/h (25 mph) rear sled test. The pulse was a 15 g double-peak acceleration with 150 ms duration. The 50th percentile Hybrid III was lap-shoulder belted in the FMVSS 208 design position. The testing included 11 <2000 MY, 8 ≥2000 MY, and 7 ABTS seats. The dummy was fully instrumented, including head accelerations, upper and lower neck 6-axis load cells, chest acceleration, thoracic and lumbar spine load cells, and pelvis accelerations. The peak responses were normalized by injury assessment reference values (IARVs) to assess injury risks. Statistical analysis was conducted using Student's t test. High-speed video documented occupant kinematics.Results: Biomechanical responses were lower with modern (≥2000 MY) seats than older (<2000 MY) designs. The lower neck extension moment was 32.5 ± 9.7% of IARV in modern seats compared to 62.8 ± 31.6% in older seats (P =.01). Overall, there was a 34% reduction in the comparable biomechanical responses with modern seats. Biomechanical responses were lower with modern seats than ABTS seats. The lower neck extension moment was 41.4 ± 7.8% with all MY ABTS seats compared to 32.5 ± 9.7% in modern seats (P =.07). Overall, the ABTS seats had 13% higher biomechanical responses than the modern seats.Conclusions: Modern (≥2000 MY) design seats have lower biomechanical responses in 40.2 km/h rear sled tests than older (<2000 MY) designs and ABTS designs. The improved performance is consistent with an increase in seat strength combined with improved occupant kinematics through pocketing of the occupant into the seatback, higher and more forward head restraint, and other design changes. The methods and data presented here provide a basis for standardized testing of seats. However, a complete understanding of seat safety requires consideration of out-of-position (OOP) occupants in high-speed impacts and consideration of the much more common, low-speed rear impacts. [ABSTRACT FROM AUTHOR]

Objective:Passengers, especially those in rear seating positions, use seat belts less frequently than drivers. In-vehicle technology can inform drivers when their passengers are unbuckled and encourage passengers to use belts. The current study collected information about drivers’ attitudes toward passenger belt use and belt reminders for front passengers and children in back seats. Methods:A national telephone survey of 1218 people 18 and older was conducted, of which 477 respondents were drivers who transport a front seat passenger at least once a week and 254 were drivers who transport an 8- to 15-year-old child in the back seat. Respondents were asked about their attitudes toward belt use by their front passengers or rear child passengers and preferences for different passenger belt reminder features. Results:Ninety percent of drivers who regularly transport front seat passengers said that the passengers always use seat belts. Reported belt use was even higher among 8- to 15-year-old children in the back seat (97%). Among the drivers whose children do not always buckle up, about half said their child unbuckled the belt during the trip. Almost every full-time belt use driver (96%) would encourage front passengers to buckle up if not belted, compared to 57 percent of part-time belt users and nonusers. In contrast, nearly every driver who transports children in the back seat would encourage their belt use, regardless of the driver's belt use habits. Most drivers who transport front passengers wanted passenger belt reminders to encourage passengers to buckle up. Most of these drivers wanted a chime/buzzer or warning light or text display and wanted the reminder to last indefinitely. Most drivers who transport child passengers in the rear seat wanted the vehicle to indicate whether child passengers are unbuckled. A large majority of these drivers wanted notifications via a visual diagram of seating positions and belt use, a chime/buzzer, and a warning light or text display. These drivers also wanted the vehicle to provide belt use information until the child buckled up. Conclusions:Many drivers, especially those who always use seat belts, said they would encourage unbuckled passengers to buckle up and supported auditory and visual belt reminders for passengers, particularly for children sitting in the back seat. Front and rear passenger reminders that last indefinitely would be acceptable to most drivers who transport these passengers. An auditory alert may be especially useful to alert drivers to children unbuckling in the back seat during a trip. [ABSTRACT FROM AUTHOR]

The implementation of haptic interfaces in vehicles has important safety and flexibility implications for lessening visual and auditory overload during driving. The present study aims to design and evaluate haptic interfaces with vehicle seats. Three experiments were conducted by testing a haptic seat in a simulator with a total of 20 participants. The first experiment measured reaction time, subjective satisfaction, and subject workloads of the haptic, visual, and auditory displays for the four signals primarily used by vehicle navigation systems. The second experiment measured reaction time, subjective satisfaction, and subjective workloads of the haptic, auditory, and multimodal (haptic + auditory) displays for the ringing signal used by in-vehicle Bluetooth hands-free systems. The third experiment measured drivers' subjective awareness, urgency, usefulness, and disturbance levels at various vibration intensities and positions for a haptic warning signal used by a driver drowsiness warning system. The results indicated that haptic seat interfaces performed better than visual and auditory interfaces, but the unfamiliarity of the haptic interface caused a lower subjective satisfaction for some criteria. Generally, participants showed high subjective satisfaction levels and low subjective workloads toward haptic seat interfaces. This study provided guidance for implementing haptic seat interfaces and identified the possible benefits of their use. It is expected that haptic seats implemented in vehicles will improve safety and the interaction between driver and vehicle. [ABSTRACT FROM PUBLISHER]

The purpose of child restraint seats (CRS) is to reduce the number of individuals killed or injured in motor vehicle (MV) crashes. Japanese Road Traffic Law 17-3-4 (April 2000) specifies a requirement that CRS be used for all children aged 0-5 years. The objective of this evaluation was to determine the legislative impact on fatalities in Japan for the period 1994-2005. Data were obtained from the Institute for Traffic Accident Research and Data Analysis. A time-series Poisson regression model was used to analyse the change (6 years pre/post) in incidence rate ratios of fatality and injury in MV crashes among children ages 0-5 years. Despite increases in CRS use, fatalities failed to decrease significantly after enactment of the law (incidence rate ratio: 0.80; 95% CI: 0.49-1.31). In 2005, 67% of children aged 0-5 years, who were killed as MV occupants were not seated in CRS. Between 2000 and 2005, the lack of CRS led to 43% of front seat passenger deaths, 54% of rear seat deaths, 143 children died in total and 500 + children were seriously injured. It was found that the compulsory CRS law enacted in April 2000 did not result in a statistically significant reduction in child MV occupant fatalities and injuries in Japan. [ABSTRACT FROM AUTHOR]