• 한국자동차공학회논문집
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• 제8권6호
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• pp.182-193
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• 2000

Several metrics have been used in crash discrimination algorithms in order to have timely air bag deployment during all frontal crash modes. However, it is still challengine to have timely air bag deployment especially during the oblique, the pole and the underride crash mode. Therefore, in this paper a new crash discrimination algorithm was proposed, using the absolute value of the deceleration change multiplied by the velocity change as a metric, and processing the metric as a function of the velocity change. The new algorithm was applied for all frontal crash modes of a minivan and a sports utility vehicle, and it resulted in timely air bag deployment for all frontal crash modes including the oblique, the pole and the underride crash mode. Moreover, it was proposed that an accelerometer be installed at each side of the rails, rockers or pillars to assess the crash severity of each side and to deploy the frontal air bags at different time especially during an asymmetric crash such as an oblique and an offset crash. As an example, the deceleration pulses measured at the left and right B-pillar·rocker locations were processed through the new algorithm, and faster time-to-fires were obtained for the air bag at the struck side for the air bag at the other side.

• 한국자동차공학회논문집
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• 제11권1호
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• pp.128-136
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• 2003

In today's design trend of vehicle structure, crush zone is fiequently reinforced by adding a box-shaped sub-frame in order to avoid an excessive deformation against a high-speed offset barrier such as EU Directive 96/97 EC, IIHS offset test. That kind of vehicle structure design results in a relatively monotonic crash pulse for airbag ECU(Electronic Control Unit) located at non-crush zone. As for an angular crash event, the measured crash signal using a single-axis accelerometer in a longitudinal direction is usually weaker than that of frontal barrier crash. Therefore, it is not so easy task to achieve a satisfactory crash discrimination performance for offset and angular crash events. In this paper, we introduce a new crash discrimination algorithm using an electronic X-Y 2-axis accelerometer in order to improve crash discrimination performance especially for those crash events. The proposed method uses a crash signal in lateral direction(Y-axis) as well as in longitudinal direction(X-axis). A crash severity measure obtained from Y-axis acceleration is used to improve the discrimination between fire and no-fire events. The result obtained by the proposed measure is logically ORed with an existing algorithm block using X-axis crash signal. Simulation and pulse injection test have been conducted to verify the performance of proposed algorithm by using real crash data of a 2,000cc passenger vehicle.

• 한국자동차공학회논문집
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• 제9권4호
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• pp.193-203
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• 2001

The Monte Carlo method was used to evaluate the reliability of crash discrimination algorithms. Through the Fast Fourier Transformation, crash pulses obtained during frontal crash tests of a mini van and a sports utility vehicle were transformed to signals in the frequency domain, and the signals were divided into basic signals and changeable signals. The changeable signals were modified through random generation, and they were combined with the basic signals. Then, the combined signals were transferred back to the time domain. In this way numerous crash pulses could be generated. For the generated pulses, crash discrimination algorithms were evaluated by examining whether they did not result in air bag deployment for the pulses requiring no air bag deployment and whether they resulted in time-to-fires faster than required time-to-fires for the pulses requiring air bag deployment. The crash discrimination algorithm in which the absolute value of the deceleration change multiplied by the velocity change or the summation of the absolute value of the deceleration change was used as a metric was Proven to be highly reliable.

• 한국자동차공학회논문집
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• 제11권2호
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• pp.148-156
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• 2003

Many car manufacturers have frequently adopted an aggressive inflator and a lower threshold speed for airbag deployment in order to meet an injury requirement for unbolted occupant at high speed crash test. Consequently, today's occupant safety restraint system has a weakness due to an airbag induced injury at low speed crash event. This paper proposes a new crash algorithm to improve the weakness by suppressing airbag deployment at low speed crash event in case of belted condition. The proposed algorithm consists of two major blocks-crash severity algorithm and deployment logic block. The first block decides crash severity with two levels by means of velocity and crash energy calculation from acceleration signal. The second block implemented by simple AND/OR logic combines the crash severity level and seat belt status information to generate firing commands for airbag and belt pretensioner. Furthermore, it can be extended to adopt additional sensor information from passenger presence detection sensor and safing sensor. A simulation using real crash data for a 1,800cc passenger vehicle has been conducted to verify the performance of proposed algorithm.

• 한국자동차공학회논문집
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• 제8권3호
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• pp.163-170
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• 2000

Accident statistics shows that the portion of fatal occupant injuries due to side impacts is considerably high. The side impact usually leads to a severe intrusion of side structure into the passenger compartment. Furthermore, the safety zone for the side impact is relatively small compared to the front impact. Those kinds of physics for side impact frequently result in a fatal injury for the occupant. Therefore, NHTSA and EEVC are trying to intensify the regulation for the occupant protection against side impact. Both the regulation and recent market trends are asking for an installation of side airbag. There are several types of system configuration for side impact sensing. In this paper, we adopt the acceleration-based remote sensing method for the side airbag control system. We mainly focus on the development of hardware and crash discrimination algorithm of remote sensing unit. The crash discrimination algorithm needs fast decision of airbag firing especially for high-speed side impact such as FMVSS 214 and EEVC tests. It is also required to distinguish between low-speed fire and no-fire events. The algorithm should have a sufficient safety margin against any misuse situation such as hammer blow, door slam, etc. This paper introduces several firing criteria such as acceleration. velocity and energy criteria that use physical value proportional to crash severity. We have made a simulation program by using Matlab/Simulink to implement the proposed algorithm. We have conducted an algorithm calibration by using real crash data for 2,500cc vehicle. The crash performance obtained by the simulation was verified through a pulse injection method. It turned out that the results satisfied the system requirements well.