Crash Sensor Polarity Independence via Signal Inversion
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Solution Overview
Problem
Current crash sensor systems rely on acceleration-based satellite sensors, which are sensitive to polarity, leading to incorrect deployments or late deployments during crashes if sensors are misconfigured or mounted incorrectly, affecting the accuracy of airbag deployment and restraint activation.
Innovation Solution
A crash sensor system with an electronic control unit (ECU) that includes accelerometers to measure longitudinal and lateral acceleration, and a processor circuit to determine crash events independently of sensor polarity, using signal processing techniques like damped integration and low pass filtering on both inverted and non-inverted signals to eliminate polarity dependence, and summing absolute values from side sensors to determine the struck side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acceleration-based satellite sensors are used to detect vehicle crashes, then crash detection capability is provided, but the system becomes sensitive to sensor polarity leading to incorrect deployments or late deployments
Solution Approach 1:
The patent applies inversion by processing both inverted and non-inverted sensor signals through the same crash discrimination algorithm. Instead of relying on correct sensor polarity, the system calculates crash metrics from both signal polarities and selects the appropriate result, effectively making the system immune to polarity errors while maintaining accurate crash detection
Solution Approach 2:
The patent changes the processing parameter by applying the same crash discrimination algorithm to both inverted and non-inverted sensor signals. This parameter change approach allows the system to evaluate crash events from both polarity perspectives and determine the correct crash direction regardless of how the sensor is physically oriented
2Ease of manufacture
If front satellite sensors are mounted backwards or misconfigured, then incorrect signals are provided to the front algorithm, but the system lacks the capability to compensate for polarity errors
Solution Approach 1:
The system processes both inverted and non-inverted versions of the satellite sensor signals through the crash discrimination algorithm. By comparing results from both signal polarities, the system can automatically determine which polarity configuration yields the correct crash direction, thereby compensating for backwards or misconfigured sensor installations without requiring manual intervention
Solution Approach 2:
The system implements a feedback mechanism where the crash discrimination algorithm processes satellite sensor signals from both polarities and uses the results to determine the actual crash direction. This feedback loop allows the system to self-correct for polarity errors by identifying which signal polarity produces consistent and logical crash direction determination across multiple sensors
3Adaptability or versatility
If side satellite sensors are mounted backwards, then incorrect signals are provided to the side algorithm, but the system cannot determine the correct struck side
Solution Approach 1:
The patent applies inversion by processing side satellite sensor signals in both inverted and non-inverted polarities through the crash discrimination algorithm. The system compares the results from both signal configurations and selects the polarity that correctly identifies the struck side, making the system tolerant to sensor mounting orientation while maintaining precise struck side identification
Solution Approach 2:
The system uses asymmetric processing where the crash discrimination algorithm evaluates satellite sensor signals differently based on their polarity. By comparing results from inverted and non-inverted signals, the system can identify the asymmetric pattern that reveals the correct struck side regardless of sensor orientation, effectively using asymmetry in signal processing to overcome physical sensor orientation issues
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
Ensures accurate crash discrimination and deployment without loss of performance, reducing the risk of safety recalls by eliminating the need for correct polarity configuration and ensuring consistent system behavior across all possible sensor mounting combinations.
Implementation Method 1
a first accelerometer constructed and arranged to measure longitudinal acceleration of the vehicle during a crash event
Implementation Method 2
a second accelerometer constructed and arranged to measure lateral acceleration of the vehicle during a crash event
Implementation Method 3
At least a pair of front crash satellite sensors are electrically connected to the ECU and are constructed and arranged to be mounted at the front of the vehicle to detect a front or a rear crash event
Implementation Method 4
At least a pair of side crash satellite sensors are electrically connected to the ECU with one of the side crash satellite sensors being constructed and arranged to be mounted at the right side of the vehicle and the other side crash satellite sensor of the pair being constructed and arranged to be mounted to the left side of the vehicle to detect a side crash event
Data Source
AI summary
A crash sensor system includes an electronic control unit (ECU). The ECU has an accelerometer to measure longitudinal acceleration of the vehicle. Front crash satellite sensors are mounted at the front of the vehicle to detect a front or a rear crash event. When a front or rear crash event occurs, the first accelerometer is utilized to determine if the crash occurred at the front or the rear of the vehicle, regardless of the polarity of the front crash satellite sensors.