Out Of Position Research Articles

Monitoring the Center of Gravity of a Vehicle Seat to Detect the Occupant Position

Deploying an airbag when a vehicle occupant is too close to it can cause injury. An adaptive Airbag Control Unit (ACU) would improve the effectiveness of the safety system, provided it is aware of the actual position of the occupants once the crash is going to occur. Occupants can be monitored with vision-based and radar-based sensing in the vehicle, but the research question is whether other reliable devices exist. In this research, a real seat is equipped with four sensors in the supports from the floor, as well as an Inertial Measurement Unit (IMU) and a microcontroller. The device is capable of identifying correct position or different Out of Position (OP) conditions and inform an adaptive ACU. The paper presents the seat layout in detail and its testing in extensive driving experiments with multiple participants. Depending on the position of the driver, the identification is correct 45–100% of the time. Monitoring the occupant position by a sensorized seat is feasible and can improve the reliability of the onboard safety system when integrated with other occupant monitoring devices.

A methodology for out of position occupant identification from pressure sensors embedded in a vehicle seat

The airbag deployment against an out of position (OP) occupant is critical. The OP condition can be hardly expected during design, while a too close airbag deployment can cause serious injuries instead of mitigating the crash effects. An adaptive airbag system would be capable to adjust its deployment to the inside scenario. However, the integration between human passengers and intelligent vehicle requires the airbag control unit to be aware of the actual occupant(s) position. In the present research, a methodology for monitoring the occupant(s) position is developed and tested with a seat prototype. A layout of thin film sensors monitors the interface pressure between the occupant and the seat cover. An inertial measurement unit (IMU) monitors the accelerations of the vehicle, considered the reference moving platform. A microcontroller is programmed for pressure sensors calibration, IMU alignment with the vehicle reference system, signals processing, OP detection, and identification. Real driving experiments on a race track were performed in the correct position and in three different OPs. The comparison of the pressure center in longitudinal and transversal directions with the vehicle acceleration enables to identify the OPs.

A Work on Welding Productivity and Economy for Smaw & Fcaw Processes

Every welding process possess its own advantages and limitations and selected after careful analysis and study of variables related to the process /product form and application criteria. Factors governing the selection of welding process includes the type of the product to be welded, material, joint geometry, field and service conditions, productivity expectations, capital cost, availability of resources, quality requirements, net cost savings etc. Currently in India, shielded metal arc welding is the major welding process dominates the welding industry and plays a key role compared to other welding processes. To achieve the higher productivity and cost savings, it is necessary to adopt suitable welding process, which can be superior to SMAW and can be justified fully in terms of productivity, quality and cost. Comparative production studies were conducted to establish the facts and to arrive conclusion. This concept will be applicable for pipe spools welding in a fabrication shop for welding groove and fillet weld joints in out of position. Process will be applied for large bore spools welding i.e. for Pipe diameter equivalent or greater than 168 mm OD and wall thickness of 7.11 mm and above. For study purpose only two welding processes were taken into account i.e. SMAW and FCAW. Since carbon steel pipe spools fabrication is 85% of the total scope, selection of the high productive and cost economic welding process plays a vital role.

The Vehicle’s Frontal Impact Influence on Driver in out of Position

The present paper underpins a contrastive study of the driver’s behavior and the injuries suffered in frontal vehicle collision, with a focus on the analysis of head-specific injuries. Four different simulation cases have been performed by means of the LS-DYNA software, where a seated belted and/or unbelted Hybrid III 50th percentile male dummy was in turns normally-positioned and out of position. Accordingly, both the analyses as well as the numerical simulation have been completed by applying a five-component model that encompasses: the dummy, the seat, the seatbelt, the steering wheel and the airbag. The assembly’s prescribed motion has been defined following a frontal Virtual Crash software-based impact simulation of a mid-size sedan at a velocity of 50 km/h against a rigid wall. The results analysis aimed at identifying the longitudinal variation laws over time in head displacements and accelerations as well as lateral motion. Admittedly, the results analysis certified that a more controlled-oriented approach to the selection of the driver’s normal positioning is a prerequisite in compliance with typical driving particularities.

The Corpuscular Method Application in OOP Child Constraint System Research and Simulation

One brief introduction of side OOP and TWG test are given. Comparison application of the airbag deployment simulation in LS-DYNA between Control Volume Method(CV), Arbitrary Lagrangian Eulerian Method(ALE) and Corpuscular Method(CPM) are descripted. CPM theory could describe the gas flow that is necessary for OOP(out of position) research. Three kinds of TWG tests were conducted and acceptable Hybrid Ⅲ 3YO dummy injury repeatability was achieved. The simulation used in side OOP simulation get good correlation results. Influences of many parameters in side OOP constraint system could be studied based on the simulation and test results.

Multiphysics out of position airbag simulation

The deployment of an airbag is most fatal and dangerous to a passenger when it is in an out of position (OOP) situation, with the airbag making contact before it is fully inflated. This can lead to severe, if not life threatening, injuries to the passenger. This situation is more commonly associated with small females and children who are positioned near to the airbag module, i.e. in an OOP load case. The aim of this research is to assess the response of a Hybrid III 5th percentile female anthropomorphic dummy positioned in an FMVSS 208 low risk static airbag deployment OOP load cases using a transient dynamic finite element program called LS-DYNA. The simulation considers the standard procedures utilised in the LS-DYNA, where assumptions such as uniform airbag pressure and temperature are made, along with a more recently developed procedure that takes into account the fluid-structure interaction between the inflating gas source and the airbag fabric, referred to as arbitrary Lagrangian Eulerian (ALE) theory. Both simulations were compared to test data received by Jaguar, indicating satisfactory results in terms of correlation, with the more recently developed procedure, ALE theory, showing the greatest accuracy, both in terms of graphical and schematic comparison, especially in the very early stages of the inflation process. As a result, the new simulation procedure model was utilised to research into the effects of changing the designs of the airbag module.

The influence of seat back rake on ligament loadings in rear-end impact

A biomechanical finite element (FE) model of the 50th percentile male human cervical spine, capable of predicting ligament loadings in whiplash scenarios, has been developed and previously reported. The study reported here analyses the influence of seat back rake on ligament injury in two scenarios: firstly, the in position, where the car occupant is looking forward and the head remains in the sagittal plane, and, secondly, the out of position, where the car occupant is initially looking slightly to one side. In both cases the results show an increase in ligament loading with a decrease of seat back rotational stiffness, substantiating the need for dynamic seat testing. Moreover, comparing individual ligament loading data shows that the initial head rotation scenario is more damaging to the cervical spine than the sagittal plane scenario, confirming a published hypothesis.

Development of a Mechatronic Adaptive Belt Force Control from the Aspect of Safety and Comfort

Reversible adaptive safety systems will become much more important with the implementation of an extensive pre crash sensing. With early detection of critical driving situations it will be possible to reduce, for instance, belt slack with the belt pretensioner. Furthermore, the prevention of Out Of Position (OOP) situations will be possible by “pulling“ the passengers out of the danger zones of the airbags with an active belt system. The usual belt force limitation used up until now can be extended in the direction of a passenger specific belt force control. This means pretensioning and limiting the belt force depending on specific passenger data, such as weight.In this paper a MADYMO vehicle model with an occupant and a finite element modelled belt system will be presented. The mechatronic belt system is equipped with an actuator and sensors measuring the current belt force. Using the measured belt force an adaptive command variable can be calculated. The actuator applies the force to the belt system. The simulation results show the reduction in occupant injuries. Furthermore modelling extensions and possible fields of application are shown in this paper.

The influence of different airbag folding patterns on the potential dangers of airbags

Airbag-induced risk of injury to occupants, especially due to Out Of Position (OOP) situations, can cause serious or fatal injuries — these are the main problems facing airbags today. The folding pattern for airbags shows a significant influence on the danger/ protection potential of the airbag. This paper focuses on a numerical investigation of these effects carried out for the purposes of a dissertation made at the Technical University of Berlin.

Why do electric fishes swim backwards? An hypothesis based on gymnotiform foraging behavior interpreted through sensory constraints

Fishes producing high-frequency wavelike electrical discharges maintain a relatively rigid body axis and swim forwards and backwards with equal ease. Using stop-action videotape filming we have observed the gymnotiform Apteronotus albifrons feeding on zooplankton and oligochaete annelids. Here it is reported that reverse swimming is characteristic of two foraging behaviors: searching for prey and assessing it. In assessing a potential prey item, fish typically scan it from tail to head by swimming backwards, then ingest it after a short forward lunge. A scan in the opposite direction-from head to tail by forward swimming-would have the prey located near the tail and out of position for the final lunge. Food choice experiments indicate that these electrosensing fish feed equally well, and take larger rather than smaller zooplankton, under light and dark conditions. Furthermore, electric fish take normal (light) colored and darkened prey (Daphnia) in a 50: 50 ratio under both dark and light conditions. These results are consistent with the interpretation that electrosensory cues are being used to detect zooplankton and other prey. Together, our observations support Lissmann's (1958, 1974) and Lissmann & Machin's (1958) assertion that backwards swimming is a component of a locomotory pattern guided by the constraints produced by an active electrical sense.

The Comparative Behavior of Grant's and Thomson's Gazelles

The comparative behavior of two associated gazelles, Gazella granti and G. thomsonii was observed in Ngorongoro Crater, Tanzania during a 2½-year antelope behavior study. Though superficially alike, the two species actually differ so much in details that morphological characters alone are probably sufficient to prevent interspecific confusion. Ecologically, the gazelles have quite different requirements: thomsonii , a grazer, prefers short-grass steppe and requires water; granti is mostly a browser and water independent. They share the same six predators in Ngorongoro, of which two jackals are considered the most important, purely on the basis of fawn predation. The same elaborate system for concealing newborn fawns is found in both gazelles and mothers sometimes cooperate in pairs to drive away pair-hunting jackals. Adult thomsonii are preferred prey of East African wild dogs, and territorial male gazelles may be most vulnerable to their hunting methods. Behavioral interaction between associated ungulates is discussed and found to extend no further than mutual response to warning signals, probably even in the gazelles. The gazelle warning signals are practically identical, featuring snorting, stamping, twitching of the side stripe, and most important, stiff-legged bounding (stotting). Gazelles and many other gregarious, territorial antelopes have the same basic social system. Differences between the gazelles may be largely based on their habitat preferences; for example, granti males defend much larger territories than do thomsonii males. Grant's nursery herds are correspondingly widely spaced and also smaller, on the average. The two seem to differ most in territorial behavior, including fighting styles. Male thomsonii are more vigorously territorial, and besides scent-marking by urination-defecation like granti , mark extensively by means of a secretion from preorbital glands, which are less developed in granti . Agonistic encounters between granti males are usually settled by means of a neck intimidation display, whereas conflicts between thomsonii males routinely end in fighting. Neck development is very important in the granti fighting style, where males lock horns and push, attempting to twist one another out of position—this is the basis for the intimidation display. In thomsonii natural selection has operated on horn configuration and fighting style to produce a relatively safe type of parry-thrust combat, thus obviating the need for a display substitute. Compared to territorial behavior, epigamic behavior in the gazelles appears remarkably similar. However, subtle-looking differences in emphasis, sequences, and combinations of the basic displays turn out to be possibly as divergent as the epigamic displays that serve to sexually isolate some other genera. But in the absence of any demonstrated tendency for these gazelles to interbreed, morphological differences alone may be considered adequate species-specific isolating mechanisms. In this respect, olfactory differences may well be more important than visual characters: thomsonii have and granti lack strong-smelling inguinal glands.