Ultrasonic Sensor Mass Elements Frequency Impedance
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Solution Overview
Problem
Current ultrasonic sensors used in vehicles for distance measurement have limited time resolution due to the need for sequential signal emission and reception, restricting the frequency range suitable for effective sound wave propagation and obstacle detection.
Innovation Solution
The ultrasonic sensor design incorporates mass elements on the membrane to alter impedance with frequency, allowing for simultaneous emission and reception at different frequencies, effectively broadening the directional characteristic of higher-order oscillations to match fundamental frequency performance, enabling faster and more accurate distance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If ultrasonic sensors emit signals sequentially at fixed frequency, then the measurement cycle is simple and reliable, but the time resolution is limited and measurement time is extended
Solution Approach 1:
The patent applies dynamics by enabling sensors to operate at multiple frequency modes (fundamental and higher-order oscillations) rather than a fixed frequency. This allows the system to dynamically select different frequencies for different measurement tasks, improving time resolution while maintaining operational simplicity through automated frequency selection by the evaluation electronics.
Solution Approach 2:
The patent changes the frequency parameter of the ultrasonic signals by utilizing multiple resonance frequencies of the sensor housing and membrane. By varying the operating frequency between fundamental (e.g., 50 kHz) and higher-order modes (e.g., 100-150 kHz), the system achieves faster measurement cycles without increasing device complexity, as the same physical sensor structure supports multiple frequency parameters.
2Loss of time
If higher frequencies are used for faster measurement, then time resolution improves, but sound wave propagation is strongly damped by air
Solution Approach 1:
The system dynamically selects between different frequency modes based on the measurement requirements and environmental conditions. When higher frequencies are needed for faster measurement, the system uses higher-order oscillations that are excited by asymmetric mass elements. When lower frequencies provide better propagation, the system reverts to fundamental oscillations, optimizing the balance between measurement speed and energy loss.
Solution Approach 2:
The patent changes the frequency parameter adaptively by utilizing the multiple resonance frequencies inherent in the sensor structure. The evaluation electronics select appropriate frequencies from the set of available modes (fundamental and higher-order), allowing the system to operate at higher frequencies when propagation conditions permit and switch to lower frequencies when damping becomes excessive, thus optimizing the energy-frequency trade-off.
3Loss of time
If multiple sensors transmit simultaneously, then time resolution improves, but signal separation becomes more difficult
Solution Approach 1:
The patent segments the frequency spectrum into distinct bands corresponding to different oscillation modes (fundamental frequency and higher-order modes). Each sensor can transmit at a specific frequency segment, and the evaluation electronics separate the signals based on these frequency segments using bandpass filters. This segmentation allows simultaneous transmission without interference, as each signal occupies a distinct frequency band that is easily separable.
Solution Approach 2:
The system changes the frequency parameter of each transmitting sensor to create distinct frequency signatures. By assigning different oscillation modes (e.g., one sensor at fundamental frequency, another at higher-order mode), the system creates separable frequency parameters that allow simultaneous operation. The evaluation electronics then separate these signals based on their frequency differences, eliminating the signal separation difficulty that would arise from identical frequency transmissions.
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 design enhances time resolution by allowing multiple sensors to operate at different frequencies simultaneously, reducing measurement time and improving the accuracy of distance determination between vehicles and obstacles.
Implementation Method 1
A piezoelectric element for generating and detecting ultrasonic vibrations
Implementation Method 2
the housings are shaped in such a way that they have a resonance in the frequency range of the ultrasonic waves used
Implementation Method 3
at least one mass element arranged on the bottom surface in such a way that the resistance of the mass element to vibration of the membrane (impedance Z) increases with increasing vibration frequency
Implementation Method 4
The sound signal generated in this way is emitted by the membrane of the ultrasonic sensor, reflected by an obstacle and received by the same or a neighboring ultrasonic sensor
Data Source
Figure 1A~1B
Figure 2~3
Figure 4
AI summary
The invention relates to an ultrasound sensor 100 which comprises a housing 101 with a peripheral side wall 102 and a base surface 104, thus being formed in a substantially pot-shaped manner. The base surface 104 is formed in a known manner as a membrane. A converter element 106, formed for example as a piezoelectric element, is disposed on the base surface 104 and serves to generate and detect ultrasound vibrations. According to the invention, at least one mass element 140a, 140b is disposed on the base surface 104 in such a way that the resistance of the mass element 140a, 140b to a vibration of the membrane increases as the vibration frequency increases.