Vehicle Panel Vibration Sensing for External Sound Detection
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Solution Overview
Problem
Classic microphones used in vehicles are sensitive to dust, moisture, and overload, making them unreliable for detecting external sound signals, especially in environments where they are exposed to the outside, such as near sirens, which is problematic for autonomous vehicles that need to recognize and locate sound signals.
Innovation Solution
A structure-borne noise sensor is attached inside the vehicle to detect external sound vibrations, which are then differentiated from internal noise using a second sensor or audio system signal, providing a robust and interference-free external sound signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a classic microphone is used to detect external sound, then sound detection sensitivity is improved, but reliability deteriorates due to sensitivity to dust, moisture, and overload
Solution Approach 1:
The patent uses the vehicle's paneling as an intermediary medium to transmit external sound vibrations to the sensor. Instead of placing the microphone directly in the sound field where it is exposed to environmental damage, the paneling acts as a mediator that transfers the sound vibrations internally to the protected sensor location.
Solution Approach 2:
The patent replaces the acoustic measurement system (microphone detecting sound waves through air) with a mechanical vibration measurement system (sensor detecting structure-borne vibrations on the paneling). This substitution allows the use of more robust sensors that are less sensitive to environmental factors like dust and moisture.
2Measurement precision
If the sensor is placed on the outside of the automobile to detect sound, then sound detection capability is improved, but protection against environmental influences deteriorates
Solution Approach 1:
The paneling serves as an intermediary that allows the sensor to detect external sound vibrations while remaining physically protected inside the vehicle. The paneling transmits the vibrations from the external sound source to the sensor without requiring the sensor to be exposed to the external environment.
Solution Approach 2:
The patent transitions from direct acoustic field measurement (requiring the sensor to be in the external sound field) to structure-borne vibration measurement (detecting vibrations transmitted through the paneling). This dimensional change in the measurement approach allows the sensor to be positioned in a protected internal location while still detecting external sounds.
3Reliability
If the sensor is placed on the inside of the automobile to protect it from environmental influences, then reliability is improved, but sound detection sensitivity deteriorates due to shielding
Solution Approach 1:
The paneling acts as an intermediary that bridges the gap between the protected internal sensor location and the external sound field. It transmits the sound vibrations through the vehicle structure, allowing the sensor to detect external sounds while remaining in the protected internal environment.
Solution Approach 2:
The patent changes the measurement parameter from acoustic pressure (requiring direct exposure to sound waves) to structural vibration (detecting mechanical oscillations of the paneling). This parameter change enables the sensor to detect external sounds through the paneling vibrations without being directly exposed to the external acoustic field.
4Reliability
If structure-borne noise sensors are used instead of classic microphones, then reliability against environmental influences is improved, but device complexity increases due to signal differentiation requirements
Solution Approach 1:
The patent segments the sound detection task into two separate measurements: one for external sound vibrations (on the paneling) and one for internal noise (inside the vehicle). By using multiple sensors in different locations, the system can separately measure and then differentiate the signals to isolate external sound from internal noise.
Solution Approach 2:
The system uses feedback from multiple sensor measurements to differentiate and isolate the external sound signal. By comparing the signals from sensors placed in different locations (one on the paneling, one inside the vehicle), the system can identify and subtract internal noise components, leaving the external sound signal.
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 approach allows for reliable detection of external sounds while minimizing interference from vehicle vibrations and internal noise, offering improved signal quality and durability against environmental influences.
Implementation Method 1
a structure-borne noise sensor is used. Structure-borne noise sensors are significantly more robust with respect to environmental influences. The structure-borne noise sensor is advantageously attached on the inside of the automobile at a first point which may be excited to oscillation via the external sound
Implementation Method 2
a MEMS-based acceleration sensor is preferably used to measure the structure-borne noise. This is a closed system which picks up the acceleration via its housing and converts it into an electrical signal
Data Source
AI summary
A device for detecting sound in the surroundings of an automobile, including a first structure-borne noise sensor, which is acoustically coupled to a first oscillating body at an outside of the automobile and provides a first audio signal, including a second audio signal, which represents sound from an interior of the automobile, and including a processing unit, which is configured to subtract at least the second audio signal from the first audio signal.