Piezoelectric Transducer Model-Based Field Equalization
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Solution Overview
Problem
In modern automobiles equipped with multiple piezoelectric sensors, interference between sensors due to acoustic bursts leads to inaccurate time-of-flight determinations and distance measurements, as sideband attenuation varies with temperature, sensor aging, and external loading, affecting the reliability of sensor arrays.
Innovation Solution
A model-based equalization method is employed to calibrate piezoelectric transducers by sensing their response as a function of frequency, deriving equivalent circuit parameters, and adapting operating parameters to counteract system level selectivity variations, which includes adjusting transmit signal current, receive signal gain, and correlator attenuation to maintain channel balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple piezoelectric sensors operate concurrently to provide tens of measurements each second, then the sensor array can monitor distances reliably, but interference between sensors occurs causing inaccurate time-of-flight determinations
Solution Approach 1:
The patent segments the measurement process by assigning unique sideband frequency signatures to each sensor channel. This allows simultaneous operation of multiple sensors without interference, as each sensor's acoustic bursts can be distinguished by their unique sideband characteristics, enabling accurate time-of-flight determination even during concurrent measurements.
Solution Approach 2:
The patent implements a feedback mechanism that continuously monitors sideband balance and dynamically adjusts operating parameters to maintain channel equilibrium. This feedback loop compensates for variations caused by temperature changes, sensor aging, and external loading, ensuring measurement accuracy is maintained over time and across environmental conditions.
2Loss of information
If sideband attenuation is used to associate acoustic bursts with originating sensors, then sensor identification is possible, but sideband balance varies with temperature, sensor aging, and external loading affecting accuracy
Solution Approach 1:
The patent performs preliminary calibration to establish baseline sideband characteristics for each sensor channel before normal operation. This preliminary action creates a reference model that accounts for individual sensor variations, enabling the system to compensate for subsequent changes due to temperature, aging, or loading by comparing current sideband measurements against the stored baseline.
Solution Approach 2:
The patent dynamically adjusts operating parameters such as excitation signal characteristics and receiver gain to compensate for sideband imbalance. By changing these parameters in response to detected sideband variations, the system maintains accurate signal association despite environmental changes, sensor aging, or external loading conditions.
3Quantity of substance
If sensor arrays are expanded to include more sensors for comprehensive monitoring, then coverage and measurement capability increase, but interference between sensors increases
Solution Approach 1:
The patent assigns unique sideband frequency signatures to each sensor channel, effectively segmenting the frequency spectrum among multiple sensors. This segmentation allows any number of sensors to operate simultaneously without interference, as each sensor's signal can be independently identified and processed based on its unique sideband characteristics.
Solution Approach 2:
The patent implements a universal sideband modulation scheme that can be applied to any number of sensors in the array. This multi-functional approach allows the same technical mechanism to scale from a few sensors to many sensors without requiring different identification methods, enabling comprehensive coverage while maintaining signal distinction through unique sideband assignments.
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 method enhances the accuracy and reliability of piezoelectric sensors by maintaining sideband balance and transducer performance, even in field conditions, thereby improving concurrent sensor operations and reducing errors in distance measurements.
Implementation Method 1
piezoelectric-based sensor includes: a transmitter that drives the piezoelectric transducer; a receiver that senses a response of the piezoelectric transducer
Implementation Method 2
a receiver that senses a response of the piezoelectric transducer
Data Source
AI summary
Disclosed sensors, sensor controllers, and sensor control methods enhance transducer performance using a model-based equalization method that can be performed in the field. One illustrative method for operating a piezoelectric-based sensor includes: sensing a response of a piezoelectric transducer as a function of frequency; deriving parameter values of an equivalent circuit for the piezoelectric transducer from the response; using a squared magnitude of the equivalent circuit's transfer function to determine a system level selectivity; and adapting at least one operating parameter of the sensor based on the system level selectivity. One illustrative controller for a piezoelectric transducer includes: a transmitter that drives the piezoelectric transducer; a receiver that senses a response of the piezoelectric transducer; and a processing circuit coupled to the transmitter and to the receiver to calibrate the transducer using the foregoing method.