Airbag Device Angular Velocity Integration for Fall Detection
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Solution Overview
Problem
Existing airbag devices struggle to instantaneously activate and inflate without malfunctioning, as setting a short actuation time leads to false activations and a long time may result in delayed inflation, making it difficult to distinguish between actual falls and other actions.
Innovation Solution
An airbag device equipped with an acceleration sensor, angular velocity sensor, and a controlling device that integrates angular velocity values over a predetermined time period to differentiate between gradual and abrupt changes in posture, ensuring accurate activation only when the airbag is needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a long actuation time is set to prevent malfunctions, then the reliability is improved, but the speed of airbag activation deteriorates
Solution Approach 1:
The system dynamically adjusts the determination time period based on the integration result of angular velocity. When the integration result exceeds the threshold, the system quickly determines a fall occurrence. The time period is extended only when necessary to accumulate sufficient angular velocity data, making the response time adaptive rather than fixed, thus resolving the contradiction between fast activation and malfunction prevention
Solution Approach 2:
The system changes the parameter of determination time period from a fixed long duration to a variable duration that adjusts based on angular velocity integration results. This parameter change allows the system to use shorter determination times when fall patterns are clearly detected through angular velocity accumulation, while extending the time only when needed, thereby improving both activation speed and reliability
2Speed
If a short actuation time is set to enable instantaneous activation, then the speed is improved, but the reliability deteriorates due to false activations
Solution Approach 1:
The system performs preliminary integration of angular velocity values over a predetermined time period before making the final determination. This preliminary action of accumulating angular velocity data allows the system to quickly identify fall patterns when they occur, enabling fast activation while the integration process itself acts as a filtering mechanism to prevent false activations from momentary angular velocity spikes
Solution Approach 2:
The angular velocity integration result serves as an intermediary parameter between the raw sensor data and the final activation decision. By using the integration result as a mediator, the system can make rapid determinations based on accumulated evidence rather than reacting to instantaneous sensor readings, thus achieving both fast activation and high reliability
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 airbag device effectively prevents malfunctions by instantaneously inflating only when necessary, accurately distinguishing between actual falls and other actions, and can inflate even during upright falls from a high place, providing comprehensive protection.
Implementation Method 1
an acceleration sensor for detecting an acceleration
Implementation Method 2
an angular velocity sensor for detecting an angular velocity
Data Source
AI summary
An airbag device for the body instantaneously activates an airbag without malfunctions.When an absolute value of an angular velocity detected by an angular velocity sensor exceeds a predetermined angular velocity value, angular velocity values are integrated from a most recent detected value to an oldest value within a predetermined time period, and if an absolute value of a resultant value of integral exceeds a predetermined value and an acceleration detected by an acceleration sensor is smaller than a predetermined acceleration, the airbag is inflated. Based on the value of the integral of the angular velocities, a case in which an angular velocity gradually increases is distinguished from a case in which an angular velocity momentarily increases, so the airbag device effectively prevents malfunctions caused by an action other than falling over. Additionally, because it is unnecessary to intentionally delay determination to prevent malfunctions, the airbag can instantaneously be inflated.