Pedestrian Impact Detection Using Multi-Sensor Thresholds
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Solution Overview
Problem
Current pedestrian protection systems face challenges in accurately detecting vehicle-pedestrian impacts and effectively mitigating the impact effects, as existing sensors and actuators may not reliably distinguish between pedestrian and non-pedestrian collisions, leading to potential misuse of impact mitigation devices.
Innovation Solution
The system employs forward-mounted accelerometers to detect pedestrian impacts by analyzing displacement and impact energy metrics, with a controller determining the occurrence of a pedestrian impact by comparing sensor signals against selectable thresholds, and actuating impact mitigation devices such as hood actuators or airbags to absorb the impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple impact sensors are used to detect pedestrian collisions, then the device complexity is reduced, but the measurement precision deteriorates because existing sensors cannot reliably distinguish between pedestrian and non-pedestrian collisions
Solution Approach 1:
The patent divides the impact detection function into multiple specialized sensors (accelerometers, force sensors, pressure sensors) distributed at different locations on the vehicle front end. Each sensor type detects specific aspects of the impact, and their combined signals enable accurate pedestrian collision identification while maintaining reasonable system complexity through modular architecture
Solution Approach 2:
The patent transitions from single-dimension impact detection to multi-dimensional analysis by incorporating signals from multiple sensor types (acceleration, force, pressure) and multiple locations. The controller analyzes the spatial distribution and temporal characteristics of these multi-dimensional signals to distinguish pedestrian impacts from other collision types, significantly improving measurement precision
2Reliability
If impact mitigation devices are activated for all detected impacts, then the reliability of pedestrian protection is improved, but the loss of energy increases due to unnecessary activation during non-pedestrian events
Solution Approach 1:
The controller continuously monitors sensor signals and uses feedback from multiple sensor types to dynamically determine whether an impact mitigation event should be activated. The system compares the characteristics of detected impacts against predefined criteria for pedestrian collisions, enabling selective actuation that improves energy efficiency while maintaining protection reliability for actual pedestrian incidents
Solution Approach 2:
The patent implements variable threshold parameters for impact detection that can be adjusted based on vehicle operating conditions, sensor signal characteristics, and impact severity. By dynamically changing these parameters, the system optimizes the balance between reliable pedestrian protection and avoidance of unnecessary energy consumption from false activations
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 solution enables accurate detection and mitigation of pedestrian impacts, reducing injury by effectively activating impact mitigation devices only during pedestrian collisions, while avoiding unnecessary activation during non-pedestrian events.
Implementation Method 1
sensing impact acceleration at a plurality of locations near the front of the vehicle
Implementation Method 2
determining displacement and impact energy metric values for each of the sensor signals
Data Source
AI summary
An apparatus (50) detects a pedestrian/vehicle impact, the apparatus including a plurality of sensors (62, 64, 66) mounted near a forward location of a vehicle (52), each sensor providing an associated signal indicative of an impact event. A metric determining device (80) determines metric values for each of the sensor signals. A controller (80) determines if any of said determined metric values indicates the occurrence of a misuse event. The controller also determines if a pedestrian/vehicle impact event is occurring by comparing the metric value of at least one sensor signal against a selectable threshold. An actuation signal is provided in response to the comparison. The selectable threshold is selected in response to the determined occurrence of a misuse event. An actuatable pedestrian impact mitigation device (84) is attached to the vehicle and is actuated in responsive to the actuation signal from said controller.