Ultrasonic Object Detection With Resonance-Frequency Signal Separation
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Solution Overview
Problem
Existing on-vehicle ultrasonic sensors face challenges in detecting near objects due to high-intensity reverberation masking the reflected waves, and their narrowband frequency characteristics make it difficult to detect beats effectively.
Innovation Solution
The object detection device employs a transceiver with a predetermined resonance frequency, generating a driving signal different from the resonance frequency to shift reverberation to resonance, using a filter to extract signals with enhanced S/N ratio, and a detection determination unit to identify near objects based on these signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a microphone is used as a transducer to transmit and receive ultrasonic waves, then the device can detect obstacles, but reverberation occurs after transmission which masks reflected waves from near objects
Solution Approach 1:
The patent changes the operating frequency parameter by driving the transducer at a frequency different from its resonance frequency. This frequency shift causes the reverberation to occur at the resonance frequency while the reflected wave remains at the driving frequency, enabling frequency-based separation of the two signals
Solution Approach 2:
The patent segments the received signal into two distinct frequency components: the reflected wave at the driving frequency and the reverberation at the resonance frequency. By separating these components in the frequency domain, the system can process them independently to eliminate masking effects
2Power
If a narrowband frequency characteristic is used in the ultrasonic sensor, then the transducer operates at a specific frequency, but it becomes difficult to detect beats and distinguish between reverberation and reflected waves
Solution Approach 1:
The patent introduces dynamic frequency operation by switching between driving at a non-resonance frequency (for transmission) and detecting at the resonance frequency (for reception). This dynamic approach allows the system to exploit both the efficiency of resonance and the separability of frequencies
Solution Approach 2:
The patent uses frequency as an intermediary parameter to distinguish between reverberation and reflected waves. By assigning different frequencies to these two signal types, the system can use frequency filtering as a mediator to separate and identify each component independently
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 enables easy detection of near objects by shifting reverberation to resonance frequency, allowing for high S/N ratio extraction of reflected waves, thus improving detection efficiency.
Implementation Method 1
a transceiver (21) having a predetermined resonance frequency
Implementation Method 2
a filter (25) configured to extract, from received signals of the transceiver (21), at least one received signal and output the extracted at least one received signal
Data Source
AI summary
An object detection device includes: a transceiver having a predetermined resonance frequency; a driving signal generation unit generating a driving signal having a driving frequency different from the resonance frequency for driving the transceiver; a filter extracting and outputting at least one received signal from received signals of the transceiver; and a detection determination unit performing object detection determination based on the extracted at least one received signal. The received signals include a first and second received signals, the first received signal having a frequency that has been shifted from the driving frequency to the resonance frequency; and the filter has a characteristic that: when extracting the first received signal, outputs the extracted first received signal as a first output signal, and when extracting the second received signal, outputs the extracted second received signal as a second output signal, the first output signal being greater than the second output signal.