Multi-Frequency Acoustic Sensor for Extended Range Detection
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Solution Overview
Problem
Current ultrasonic systems for detecting the acoustic environment face limitations in range and robustness due to high frequency attenuation, interference, and complex signal generation, leading to inefficient distance measurement and movement detection.
Innovation Solution
The method involves emitting sound pulses with different center frequencies simultaneously or in close succession, using a frequency range divided into bands with significant frequency spacing, allowing for easier signal evaluation and increased range by utilizing both ultrasonic and human hearing frequency ranges, and employing modulation techniques to avoid interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ultrasonic frequency range is used for acoustic environment detection, then interference-free detection is achieved, but signal attenuation increases with frequency leading to limited range
Solution Approach 1:
The ultrasonic frequency range is divided into multiple frequency bands (e.g., 40-50 kHz, 50-60 kHz, etc.), with each band handled by dedicated transducers. This segmentation allows the system to operate in multiple frequency ranges simultaneously, balancing the low attenuation of lower frequencies with the low interference of higher frequencies, thereby extending the overall detection range while maintaining signal clarity
Solution Approach 2:
The system transitions from single-frequency operation to multi-frequency band operation by adding the frequency dimension. Multiple transducers operate at different frequency bands simultaneously, creating a multi-dimensional frequency space that overcomes the limitations of single-frequency systems regarding both attenuation and interference
2Length of stationary object
If pulse duration is extended to increase signal energy, then measurement range is improved, but spatial resolution of transit time measurement decreases
Solution Approach 1:
The system segments the measurement function across multiple frequency bands and multiple short pulses. Instead of relying on a single long pulse for range extension, the system uses multiple shorter pulses at different frequencies, each providing precise temporal resolution. The combination of these segmented measurements achieves extended range while preserving spatial resolution
Solution Approach 2:
The system employs multiple partial measurements (multiple short pulses at different frequencies) that individually provide limited range but collectively achieve extended measurement range. Each pulse contributes a portion of the total measurement capability, and their combination exceeds the limitations of any single pulse
3Ease of manufacture
If narrowband converters are used to generate signal frequency by switching transmission currents, then signal generation is simplified, but receivers are more susceptible to interference
Solution Approach 1:
The system segments the frequency generation across multiple narrowband converters operating at different frequency bands. Each converter generates its designated frequency by switching transmission currents, which is simple to implement. The multiple frequency bands work together to provide robust detection that is less susceptible to interference at any single frequency
Solution Approach 2:
The narrowband converters are designed to be universal in their simplicity of operation while serving multiple frequency bands. Each converter performs the same simple function (frequency generation by switching) but contributes to the overall multi-frequency system that achieves both ease of manufacture and interference resistance
4Adaptability or versatility
If broadband converters are used to emit sound signals, then signal generation capability is enhanced, but device complexity increases significantly
Solution Approach 1:
The system segments the broadband signal generation function into multiple narrowband converters, each handling a specific frequency band. This segmentation reduces the complexity of each individual converter while collectively providing broadband capability. Each converter generates signals in its designated band, and the combination achieves enhanced signal generation capability without the complexity of true broadband converters
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 enhances the range and robustness of acoustic environment detection, achieving reliable and cost-effective sensors with high reliability and reduced interference, enabling clear echo signal detection even at larger distances.
Implementation Method 1
determining the position and/or the movement of objects in the vicinity of a movement aid by means of sound signals emitted in pulses and reflected on at least one object
Data Source
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AI summary
A method for determining the position and/or the movement of objects in the surroundings of a movement assistant by means of sound signals which are emitted in the form of pulses and are reflected at at least one object is provided, in which method at least one sound pulse (S1, S2, S3), which has frequencies below the ultrasonic frequency range, is received and used. In addition, an associated device for carrying out the method, a cover apparatus for the device and a vehicle having the device according to the invention are disclosed.