Variable Force Limiter Control System for Vehicle Collision Severity Prediction
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Solution Overview
Problem
Existing seatbelt retractor systems struggle to accurately determine the severity of a collision in real-time, leading to inappropriate timing for switching force limiter loads, resulting in erroneous operations of the force limiter mechanism.
Innovation Solution
A variable force limiter control system that includes a relative speed sensor to detect the vehicle's speed before a collision, an acceleration sensor to detect initial collision acceleration, and an electronic control unit to predict the collision severity based on both relative speed and acceleration, allowing for timely and accurate switching of the force limiter load mode from high to low.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the force limiter load mode is switched based on detected acceleration signal after collision, then the system can respond to collision severity, but the switching timing is delayed until the end of collision, causing erroneous switching
Solution Approach 1:
The system performs preliminary action by predicting collision severity using relative speed detection before the collision occurs. The ECU determines the necessary force limiter load mode in advance based on predicted severity, enabling timely switching without waiting for collision to complete. This resolves the contradiction by acting beforehand rather than waiting for full collision data.
Solution Approach 2:
The system introduces an intermediary approach by using predicted collision severity as a preliminary indicator, then refining the decision with actual acceleration data during the initial collision stage. This two-stage process (prediction + verification) allows timely switching while maintaining accuracy, resolving the timing-accuracy contradiction.
2Loss of time
If the force limiter load mode is switched based on predicted collision severity, then the switching timing can be appropriate, but erroneous switching may occur due to inaccurate prediction
Solution Approach 1:
The system implements feedback by using actual acceleration detection during the initial collision stage to verify and adjust the predicted collision severity. The ECU compares predicted severity with actual acceleration data, confirming whether mode switching is necessary. This feedback mechanism prevents erroneous switching while maintaining timely response.
Solution Approach 2:
The system performs preliminary prediction of collision severity based on relative speed, then uses this preliminary information to prepare for timely switching. The prediction enables early decision-making, while subsequent verification ensures accuracy, resolving the contradiction between timing and reliability.
3Device complexity
If only acceleration detection is used to determine collision severity, then the system is simple, but accurate determination requires integration over the entire collision period, delaying switching
Solution Approach 1:
The system performs preliminary determination of collision severity using relative speed detection before collision occurs. This preliminary action provides an early estimate of severity, enabling timely switching decision without waiting for complete acceleration integration. The simplicity of speed sensing is maintained while gaining time advantage.
Solution Approach 2:
The system segments the collision assessment process into two parts: preliminary severity prediction using relative speed, and verification using initial stage acceleration. This segmentation allows timely switching based on prediction while using acceleration data only when necessary, reducing overall time loss without requiring continuous acceleration integration.
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 system enables accurate determination of the necessity for switching the force limiter load mode, reducing erroneous operations and ensuring appropriate timing, thereby enhancing safety by preventing or minimizing the risk of occupant collision with vehicle interior components.
Implementation Method 1
a relative speed sensor that detects a relative speed between the vehicle and a collision object before a collision
Implementation Method 2
an acceleration sensor that detects an acceleration of the vehicle
Data Source
AI summary
A variable force limiter control system for a vehicle includes a variable force limiter mechanism, a relative speed sensor, an acceleration sensor and an electronic control unit. The variable force limiter mechanism is configured to change a force limiter load. The relative speed sensor is configured to detect a relative speed of the vehicle with respect to a collision object before a collision. The acceleration sensor is configured to detect an acceleration of the vehicle. The electronic control unit is configured to predict a severity of a collision on the basis of at least the relative speed. The electronic control unit is configured to control the force limiter load on the basis of both the predicted severity and the acceleration in an initial stage of the collision of the vehicle.