Pedestrian Impact Identification via Bumper Stiffness Mapping
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Solution Overview
Problem
Existing vehicle systems face challenges in accurately differentiating between pedestrians and other objects impacting the vehicle bumper during collisions due to non-homogeneous bumper stiffness, which affects the deformation and intrusion patterns, making precise impact location identification difficult.
Innovation Solution
A system utilizing multiple accelerometers to detect acceleration changes, calculate center strength, and determine a normalized intrusion value based on bumper stiffness factors, allowing for accurate object classification and activation of pedestrian protection systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bumper stiffness is made homogeneous, then impact location identification becomes easier, but bumper design flexibility and energy absorption capability are reduced
Solution Approach 1:
The system applies local quality by creating a stiffness map that identifies different stiffness characteristics at various locations on the bumper surface. Each location is assigned a specific stiffness factor based on local deformation behavior, allowing the system to account for non-homogeneous stiffness without requiring the entire bumper to be uniformly stiff. This enables accurate impact location identification while preserving design flexibility.
2Measurement precision
If multiple sensors are deployed across the bumper surface, then impact location precision improves, but system complexity and cost increase
Solution Approach 1:
The bumper surface is segmented into multiple zones with distinct stiffness characteristics, and sensors are strategically positioned to cover these segments. The system processes sensor data by comparing acceleration signals against a pre-established stiffness map, which divides the bumper into regions with different expected deformation behaviors. This segmentation approach achieves precise impact location identification with a manageable number of sensors.
3Loss of energy
If bumper stiffness varies across the surface, then energy absorption is optimized, but impact location identification becomes more difficult
Solution Approach 1:
The system performs preliminary characterization of the bumper's stiffness distribution through controlled impact tests before actual operation. During these calibration tests, the bumper is impacted at various locations with known forces, and the resulting accelerations are recorded to create a stiffness map. This pre-established reference data allows the operational system to accurately identify impact locations by comparing real-time sensor readings against the predetermined stiffness characteristics, eliminating the need to solve the inverse problem in real-time.
4Reliability
If impact detection threshold is lowered, then pedestrian detection sensitivity increases, but false positives from other objects increase
Solution Approach 1:
The system uses parameter changes by analyzing multiple characteristics of the impact signal simultaneously, including acceleration magnitude, pulse duration, frequency content, and the spatial distribution of acceleration across multiple sensors. Pedestrian impacts produce a specific signature across these parameters that differs from other objects. By evaluating the combination of these parameters against the bumper stiffness map and impact location, the system achieves high detection sensitivity while maintaining low false positive rates through multi-parameter discrimination rather than relying on a single threshold.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise identification of impact locations and object types, effectively activating pedestrian protection systems only when a pedestrian is detected, thereby improving safety by accurately differentiating between pedestrian and non-pedestrian impacts.
Implementation Method 1
a plurality of sensors positioned to detect acceleration of the vehicle bumper relative to the vehicle. Changes in acceleration as detected by the sensors represent an intrusion into the bumper surface caused by an object colliding with the vehicle bumper
Implementation Method 2
When an object strikes the vehicle bumper, the bumper deforms differently depending on the object's mass, the impact speed, and the bumper stiffness at the location of the impact
Data Source
AI summary
A system for identifying an object impacting a vehicle bumper during a collision. The system receives acceleration values from each of a plurality of sensors and calculates a center strength value based on the acceleration values. The center strength value is indicative of the amount of force that is applied to the center of the vehicle bumper. The system then determines a preliminary impact location on the vehicle bumper based at least in part on the acceleration values. A normalized intrusion value is calculated based on the center strength value, the impact location, and a bumper stiffness factor. The bumper stiffness factor is indicative of the stiffness of the bumper at the impact location. The system then identifies the object impacting the vehicle bumper based at least in part on the normalized intrusion value.