Pedestrian Collision Detection via Dynamic Pressure Integration
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Solution Overview
Problem
Existing collision detecting devices struggle to accurately discriminate between pedestrian collisions and collisions with on-road fixed objects, such as poles, due to similar pressure changes and integrated values, especially when encountering children or adults, leading to difficulties in setting threshold values.
Innovation Solution
A collision detecting device that calculates a discrimination value by integrating pressure and vehicle speed at a sectional integration width specific to the vehicle's speed, and corrects for dead zones and energy absorption, allowing for accurate differentiation between pedestrian and fixed object collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the integrated value of pressure is used to discriminate collided objects, then discrimination can be performed, but accurate discrimination between pedestrian and fixed object collisions becomes difficult due to similar integrated values
Solution Approach 1:
The patent divides the pressure detection timeline into multiple time sections and performs integration separately for each section. By segmenting the integration process into first and second time sections with different integration widths, the system can distinguish between pedestrian collisions (which produce characteristic pressure patterns across time segments) and fixed object collisions (which produce different patterns), thereby resolving the contradiction between measurement precision and discrimination reliability.
2Measurement precision
If a threshold value is set suitable for child collision detection, then child collisions can be detected, but discrimination from on-road fixed objects becomes difficult
Solution Approach 1:
The patent dynamically adjusts the integration width parameter based on the detected maximum pressure value. When maximum pressure is low (indicating possible child collision), a larger integration width is applied to accumulate sufficient impulse value for detection. When maximum pressure is high (indicating possible fixed object collision), a smaller integration width prevents excessive accumulation. This dynamic adaptation allows the system to maintain high detection accuracy for children while avoiding false positives with fixed objects.
3Quantity of substance
If the entire pressure detection period is integrated, then complete impulse information is obtained, but discrimination between different collision types becomes difficult
Solution Approach 1:
The patent segments the pressure detection period into multiple time sections and performs separate integration for each segment. This segmentation preserves the temporal distribution characteristics of the pressure signal, allowing the system to maintain complete impulse information while simultaneously enabling collision type discrimination through analysis of how impulse is distributed across different time segments.
Solution Approach 2:
The patent applies different integration widths to different time sections based on local characteristics of the pressure signal. The first time section uses a first integration width while the second time section uses a second integration width, optimizing the extraction of discriminative features from different phases of the collision event.
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
The device effectively discriminates between pedestrian and on-road fixed object collisions by using a corrected discrimination value, improving accuracy and reducing false positives or negatives, especially in cases involving children or adults.
Implementation Method 1
pressure detecting means for detecting the pressure of the pressure chamber
Implementation Method 2
the fact that the impulse and the momentum generated by a collision are equal is utilized, and the effective mass of the collided object can be calculated as the discrimination value
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An object is to be able to accurately discriminate an object of a collision. A device has a collision detection ECU (26) to which are connected a pressure sensor (24) that detects pressure within a pressure chamber (22), and a vehicle speed sensor (28) that detects vehicle speed, and the collision detection ECU (26) determines effective mass of a collided object on the basis of an integrated value obtained by integrating, at a predetermined sectional integration width, detection results of the pressure sensor (24), and a converted vehicle speed signal obtained by subtracting a predetermined value α from a vehicle speed signal of the vehicle speed sensor (28) by using a predetermined vehicle speed converting map or the like. Then, when the determined effective mass exceeds a predetermined threshold value, the collided object is discriminated as a pedestrian.