Vehicle Safety System with Chest Stiffness Control
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Solution Overview
Problem
Existing vehicle safety systems fail to tailor the retarding forces applied to occupants during a crash to individual variations in chest stiffness, leading to potential injuries from improper force distribution.
Innovation Solution
A vehicle safety system that uses a control unit and a chest model to adjust the restraining forces based on the occupant's chest mass and stiffness, incorporating a spring and damper model to simulate the chest's motion and apply tailored forces via seat belts and airbags.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retarding forces are increased to prevent occupant striking the steering wheel or dashboard, then protection against impact injury is improved, but the risk of chest injury from excessive force increases
Solution Approach 1:
The system changes the parameter of retarding force dynamically based on detected chest stiffness characteristics. By measuring resonant frequency and using it to infer chest stiffness, the control system adjusts the force magnitude applied by the seat belt and airbag, ensuring adequate protection without exceeding safe force thresholds for each occupant's chest characteristics.
Solution Approach 2:
The system employs feedback by measuring the resonant frequency of the chest during normal operation, using this information to determine chest stiffness characteristics, and then adjusting the retarding force parameters accordingly. This closed-loop approach ensures forces are tailored to individual occupants rather than applying uniform force levels.
2Reliability
If retarding forces are varied in accordance with occupant mass and crash severity, then protection effectiveness is improved, but the system fails to account for individual variations in chest stiffness
Solution Approach 1:
The system replaces direct mechanical measurement of chest stiffness with a non-contact or minimal-contact method of measuring resonant frequency. By exciting the chest at its natural frequency and measuring the response, the system can infer stiffness characteristics without applying significant force, then uses this information to control the retarding forces from the seat belt and airbag.
3Device complexity
If a rigid control approach is used to ensure consistent force application, then system simplicity is maintained, but the system cannot adapt to individual occupant characteristics
Solution Approach 1:
The system performs self-characterization by automatically measuring the resonant frequency of each occupant's chest and using this information to configure the retarding force parameters. No manual input or complex calibration is required from the user; the system adapts itself based on the physical characteristics it detects, maintaining simplicity while achieving personalization.
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 system effectively reduces the severity of injuries by applying customized retarding forces that account for individual variations in chest stiffness, minimizing chest deflection and spinal acceleration during crashes.
Implementation Method 1
a chest spring representing the stiffness of the chest of the occupant
Implementation Method 2
the model further comprises a damper provided in parallel with the chest spring
Data Source
Figure 1~3
AI summary
A vehicle safety system, comprising: at least one restraining device (2a5 4) operable to apply a restraining force to the chest of an occupant when it is determined that the vehicle is involved in a crash situation; and a control unit (Ia) operable to control the restraining force applied by the at least one restraining device (2a, 4) to the chest of an occupant in accordance with a properly of the chest of the occupant, relating to the stiffness of the chest.