Active Damping Circuit for Ultrasonic Transducer Self-Oscillation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing distance measurement systems using piezoelectric transducers face issues with self-oscillation and reverberation, which can lead to inaccurate measurements and saturation of receiver circuits, especially when attached to moving objects, and the use of parallel resistors to reduce reverberation time also diminishes signal reception.
Innovation Solution
An acoustic transducer controller is introduced that includes an active damping circuit to reduce self-oscillation by applying a damping signal with a polarity opposite to the transducer's current during reverberation, thereby minimizing energy storage and reverberation time, and a closed-loop control mechanism to adjust the damping signal based on state-space parameters for efficient energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a parallel resistor is added to reduce reverberation time, then the reverberation time is reduced, but the signal received by the electronics is reduced
Solution Approach 1:
The patent divides the damping function into two separate circuits: a parallel resistor circuit for rapid initial damping and an active damping circuit for sustained damping. This segmentation allows each circuit to be optimized for its specific function without compromising the other, resolving the contradiction between rapid reverberation reduction and signal preservation.
Solution Approach 2:
The patent introduces an active damping circuit as an intermediary solution that provides damping without the signal attenuation problems of parallel resistors. This active circuit acts as a mediator between the transducer and the measurement system, providing the necessary damping while preserving signal integrity through controlled energy dissipation.
2Device complexity
If the transducer is used for both transmitting and receiving acoustic waves, then the system complexity is reduced, but the receiver circuits are saturated during reverberation
Solution Approach 1:
The patent applies preliminary damping action immediately after transmission to suppress reverberation before it can saturate the receiver circuits. By proactively reducing the reverberation energy through the combined parallel resistor and active damping circuits, the system prevents saturation from occurring, thereby maintaining measurement precision while using a single transducer for both transmission and reception.
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 solution effectively reduces the reverberation time of the transducer, improving the accuracy of distance measurements by dissipating stored energy without affecting the signal quality during the measurement phase, thus enhancing the overall performance of the distance measurement system.
Implementation Method 1
Many distance measurement systems were based on ultrasonic principle and utilized a piezoelectric transducer that was controlled by electronics or other circuitry
Implementation Method 2
When the transmission was terminated, the piezoelectric transducer typically would self-oscillate or reverberate such as at a resonant frequency of the transducer
Implementation Method 3
An acoustic transducer controller is introduced that includes an active damping circuit to reduce self-oscillation by applying a damping signal with a polarity opposite to the transducer's current during reverberation, thereby minimizing energy storage and reverberation time
Data Source
AI summary
In an embodiment, a transducer controller is configured to apply a damping signal to reduce energy stored in the transducer after the transducer has been driven with a drive signal to form a transmitted acoustic signal.