Rollover Judgment Using Fixed Thresholds
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Solution Overview
Problem
Conventional rollover judging devices employ complex two-dimensional mapping methods, requiring variable judgment thresholds and complicated arithmetic processes, which are difficult to implement in actual vehicle driving tests and lack simplicity in expressing rollover severity.
Innovation Solution
A rollover judging device using angular velocity and acceleration sensors, with integration processing and weighting factors to adjust and calculate angular velocity components, simplifying the judgment process by setting a fixed threshold, thereby improving reliability and expressing rollover severity as a percentage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a two-dimensional mapping method with variable judgment thresholds is used, then the rollover judgment can be made according to vehicle behavior, but the computation process becomes complicated and reliability decreases
Solution Approach 1:
The patent changes the approach from variable thresholds to fixed thresholds. Instead of computing variable judgment thresholds based on vehicle behavior (ω, θv mapping), the invention uses fixed threshold values (Th1, Th2) combined with fixed weighting factors (α, β) in a simplified arithmetic expression: |α·ω + β·θv| > Th. This resolves the contradiction by maintaining adaptability through proper weighting while eliminating the complexity of variable threshold computation.
2Adaptability or versatility
If variable judgment thresholds are computed for each quadrant, then the judgment can account for different vehicle conditions, but the arithmetic processing becomes more complex
Solution Approach 1:
The patent creates a universal judgment formula that works for all quadrants and vehicle conditions without requiring separate threshold computations. The single arithmetic expression |α·ω + β·θv| > Th with fixed parameters serves all judgment scenarios, eliminating the need for quadrant-specific variable thresholds while maintaining comprehensive adaptability through the weighting factors.
3Measurement precision
If a two-dimensional mapping method is used, then rollover judgment can be made, but it is difficult to express the severity of rollover phenomenon using a simple percentage
Solution Approach 1:
The patent transforms the complex two-dimensional mapping assessment into a simplified scalar value assessment. By computing |α·ω + β·θv| and comparing it to a fixed threshold, the system generates a single numerical value that directly represents rollover severity, enabling easy expression as a percentage of the threshold value and simplifying severity communication.
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 simplifies the rollover judgment process, enhances reliability by reducing arithmetic complexity, and effectively expresses rollover severity using a simple percentage, improving accuracy and passenger safety.
Implementation Method 1
an angular velocity sensor for measuring an angular velocity component of a vehicle in a direction of a rollover of the vehicle
Implementation Method 2
an acceleration sensor for measuring either of at least an acceleration component of the vehicle in a rightward or leftward direction and an acceleration component of the vehicle in an upward or downward direction
Implementation Method 3
an integration processing means for adjusting a magnitude of the angular velocity component measured by the above-mentioned angular velocity sensor on a basis of the acceleration component measured by the above-mentioned acceleration sensor, and for calculating an angle component by integrating with respect to time the above-mentioned adjusted angular velocity component
Data Source
AI summary
A rollover judging device adjusts the magnitude of an angular velocity component ω of a vehicle in a direction of a rollover, which is measured by an angular velocity sensor 1, by using an ω adjusting unit 3c on the basis of an acceleration component of the vehicle in its rightward or leftward direction or in its upward or downward direction, which is measured by an acceleration sensor 2, calculates an angle component θo by integrating with respect to time this adjusted angular velocity component ωo by using an integrator 3d, carries out predetermined multiplication and addition processes by using a judging means 4 on the basis of this angle component θo and the measured angular velocity component ω, and, when the result of this addition process exceeds a preset threshold Th, outputs a signal indicating judgment of occurrence of a rollover to an air bag control device 5.