Pedestrian Impact Sensing Using Acceleration Envelopes
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Solution Overview
Problem
Current pedestrian protection systems in vehicles face challenges in accurately distinguishing between pedestrian and non-pedestrian impacts, leading to potential inappropriate deployment of countermeasures.
Innovation Solution
A detection system utilizing sensors mounted on the vehicle's bumper to calculate an acceleration envelope and count zero crossings in impact signals, employing a discrimination hyperplane to differentiate between pedestrian and non-pedestrian impacts, thereby triggering appropriate countermeasures such as deploying a pop-up hood or external airbags.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pedestrian protection systems deploy countermeasures based on impact detection, then pedestrian injury risk is reduced, but false deployment occurs when non-pedestrian objects are misidentified
Solution Approach 1:
The impact detection function is divided into multiple independent analysis components: acceleration envelope calculation, zero-crossing count analysis, and discrimination hyperplane evaluation. Each component processes specific features of the impact signal separately, allowing the system to comprehensively evaluate impact characteristics and reduce misidentification of non-pedestrian objects as pedestrians.
2Difficulty of detecting and measuring
If sensors are mounted on the bumper to detect impacts, then impact detection capability is improved, but the system cannot distinguish between pedestrian and non-pedestrian impacts
Solution Approach 1:
The system transitions from one-dimensional impact detection (simple presence/absence) to multi-dimensional analysis by calculating acceleration envelopes and zero-crossing counts. This creates a two-dimensional feature space that enables the discrimination hyperplane to accurately separate pedestrian impacts from non-pedestrian impacts, solving the precision problem while maintaining detection capability.
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
Effectively reduces the risk of pedestrian injury by accurately identifying impacts and deploying countermeasures only when a pedestrian is involved, minimizing unnecessary activations and ensuring timely protection.
Implementation Method 1
A sensor may be mounted to the bumper and output an impact signal
Data Source
AI summary
A vehicle system includes a sensor that outputs an impact signal and a processing device that is programmed to calculate an acceleration envelope from the impact signal, determine a number of times the impact signal crosses a predetermined threshold, and determine whether the impact signal represents a pedestrian impact. Whether the impact is a pedestrian impact is based at least in part on the acceleration envelope and the number of times the impact signal crosses the predetermined threshold.