Ultrasonic Transducer Controller Frequency Adaptation
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Solution Overview
Problem
Ultrasonic transducers used in distance measuring systems face challenges due to variations in resonant frequency caused by environmental conditions such as temperature and the presence of rain or ice, leading to reduced accuracy and sensitivity in measuring distances.
Innovation Solution
A transducer controller is designed to adjust the drive frequency of the ultrasonic transducer to match its resonant frequency, using a method that involves detecting frequency differences and phase errors through reverberation signals, allowing for improved sensitivity and accuracy in distance measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transducer operates at a fixed drive frequency, then the device complexity is reduced, but the measurement precision deteriorates due to resonant frequency variations caused by environmental conditions
Solution Approach 1:
The patent implements a dynamic frequency adjustment mechanism where the controller continuously monitors the transducer's resonant frequency and adapts the drive frequency accordingly. This dynamic adaptation resolves the contradiction by allowing the system to maintain measurement precision without requiring an overly complex fixed-frequency control structure.
Solution Approach 2:
The system employs feedback through reverberation signal analysis to detect changes in resonant frequency. The controller uses this feedback information to adjust the drive frequency, thereby maintaining measurement accuracy while keeping the overall controller structure manageable through intelligent feedback-based adaptation.
2Measurement precision
If the transducer resonant frequency is adjusted to compensate for environmental changes, then the measurement precision is improved, but the device complexity increases due to additional control circuitry
Solution Approach 1:
The controller is designed to perform multiple functions: generating drive signals, analyzing reverberation signals, detecting resonant frequency, and adjusting drive frequency. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby improving measurement precision while limiting the increase in overall device complexity.
Solution Approach 2:
The system uses the transducer's own reverberation signals to detect resonant frequency changes and automatically adjusts the drive frequency without requiring external calibration or additional sensing components. This self-service approach improves measurement precision while minimizing added complexity.
3Reliability
If the drive frequency is continuously adjusted to match resonant frequency, then the reliability is improved, but the loss of time increases due to frequency detection and adjustment processes
Solution Approach 1:
The system performs resonant frequency detection and drive frequency adjustment periodically rather than continuously. This periodic operation maintains measurement reliability by regularly updating the frequency match while reducing the time loss associated with constant frequency adjustment processes.
Solution Approach 2:
The controller performs preliminary frequency detection and adjustment before actual distance measurements are taken. This preliminary action ensures the drive frequency is optimized for the current environmental conditions before measurement begins, improving reliability while minimizing time loss during the actual measurement process.
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
The controller effectively adjusts the drive frequency to match the resonant frequency, enhancing the sensitivity and range of ultrasonic transducers, thereby improving the accuracy and reliability of distance measurements despite environmental changes.
Implementation Method 1
an ultrasonic transducer may have been used as a portion of a distance measuring system
Implementation Method 2
determine a phase error between the first frequency and a resonant frequency of the transducer
Implementation Method 3
the transducer resonant frequency may have been be dependent upon the ambient temperature
Data Source
AI summary
In one embodiment, a transducer controller is configured to form a drive signal with a first frequency to drive a transducer. The drive signal has a period and a half-period and drives the transducer for a first portion of the half-period. The transducer controller is configured to, for a second portion of the half-period, sense a voltage formed by the transducer, measure portions of the voltage and estimate a phase error between the first frequency and a resonant frequency of the transducer, and to adjust the first frequency to a second frequency that reduces the phase error.