Pedestrian Impact Detection Using Bumper and Hood Sensors
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Solution Overview
Problem
Existing pedestrian impact detection systems for vehicles are costly, difficult to deploy, and often detect collisions too late to effectively reduce pedestrian injury, as they require contact with the vehicle hood and are prone to false triggers from non-pedestrian impacts.
Innovation Solution
A sensing method using a combination of acceleration sensors at the front bumper and laterally distributed object detection sensors above the hood, which define a detection zone and confirm a pedestrian impact if an object is detected within a predefined time interval following an initial impact, while considering vehicle speed to filter out stationary or slow-moving events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors (bumper impact sensors and hood impact sensors) are equipped to reliably detect pedestrian impacts, then detection reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple sensing functions into a single integrated system. The hood impact sensor simultaneously detects both pedestrian impacts and abuse events by analyzing impact characteristics, eliminating the need for separate bumper and hood impact sensors while maintaining reliable detection capability.
Solution Approach 2:
The patent changes the parameters of the single hood impact sensor by implementing signal processing that analyzes impact magnitude, duration, and frequency characteristics. This allows the same sensor to distinguish between pedestrian impacts (lower magnitude, specific duration) and abuse events (higher magnitude), achieving reliable detection without additional sensors.
2Reliability
If safety devices are deployed only after hood contact is detected, then false deployment from non-pedestrian impacts is reduced, but response time is delayed
Solution Approach 1:
The patent performs preliminary analysis of impact characteristics at the moment of hood contact. By evaluating the impact magnitude and duration immediately when the sensor is triggered, the system determines whether deployment is necessary before actually deploying, enabling faster response while maintaining reliability.
Solution Approach 2:
The patent implements a feedback mechanism where the impact sensor continuously monitors hood contact characteristics and provides real-time feedback to the control system. This allows the system to assess the nature of the impact and make deployment decisions based on actual measured parameters rather than predetermined conditions.
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
This method provides earlier and more reliable detection of pedestrian impacts, reducing the risk of injury by deploying safety devices before contact with the hood and minimizing false deployments, thus enhancing pedestrian safety in a cost-effective manner.
Implementation Method 1
the initial impact is detected with an acceleration sensor disposed in or near the front bumper
Implementation Method 2
the detection zone is defined by proximity sensors disposed on the hood or behind the windshield of the vehicle
Data Source
AI summary
The collision of a vehicle with a pedestrian is detected by the presence of a foreign object in a sensing zone above the hood of the vehicle within a prescribed time of an initial impact with the bumper of the vehicle. The initial impact is detected with an acceleration sensor disposed in or near the front bumper and the sensing zone is defined by object detection sensors disposed on the hood or behind the windshield of the vehicle. Vehicle speed is used to discriminate against events that occur while the vehicle is stationary or moving very slowly.