Ultrasonic Transducer Frequency Tracking for Sensor De-Icing
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Solution Overview
Problem
Existing ultrasonic cleaning devices for automotive sensors lack optimal efficiency, diagnostic capabilities, and adaptability to different environmental conditions, leading to ineffective removal of contaminants like water droplets, ice, and snow.
Innovation Solution
A controller that drives a cleaning transducer with a periodic waveform, measures impedance voltage, and adjusts the drive frequency to track the resonance frequency of the transducer, performing diagnostic and cleaning operations to adapt to environmental changes and efficiently remove contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drive frequency is fixed, then the device complexity is reduced, but the cleaning efficiency decreases when environmental conditions change
Solution Approach 1:
The patent implements dynamic frequency adjustment by continuously monitoring the transducer's resonance frequency through impedance measurements and automatically adapting the drive frequency to match the resonance peak. This allows the system to maintain optimal cleaning efficiency across varying environmental conditions (temperature, contaminants) without requiring manual intervention or complex user input, thus resolving the contradiction between maintaining high productivity and avoiding excessive complexity.
Solution Approach 2:
The patent employs feedback control by measuring the transducer's impedance characteristics during operation and using this information to adjust the drive frequency. The controller monitors resonance frequency shifts caused by environmental changes and continuously tunes the drive signal to remain at the optimal resonance peak, thereby maintaining high cleaning efficiency while managing complexity through automated closed-loop control.
2Measurement precision
If diagnostic operations are performed continuously, then the measurement precision of resonance frequency is improved, but the use of energy increases
Solution Approach 1:
The patent implements periodic diagnostic operations where the controller performs resonance frequency measurements at scheduled intervals rather than continuously. During cleaning operations, the system performs diagnostics periodically to track resonance shifts, and during idle periods, it performs comprehensive scans to establish baseline characteristics. This periodic approach maintains sufficient measurement precision to detect environmental changes while significantly reducing energy consumption compared to continuous monitoring.
Solution Approach 2:
The patent applies partial action by performing diagnostic measurements only when necessary - during cleaning operations to track resonance frequency drift and during idle periods for baseline establishment - rather than continuously monitoring. The system performs sufficient measurements to maintain optimal performance but avoids excessive diagnostic activity that would waste energy during stable operating conditions.
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 tracks and adjusts the drive frequency to match the resonance frequency, ensuring efficient cleaning and de-icing operations, enhancing the reliability and safety of automotive sensors by maintaining unobstructed sensor performance.
Implementation Method 1
a cleaning transducer configured to impart ultrasonic vibrations to the lens surface
Implementation Method 2
control logic configured to adjust the drive frequency using the high impedance voltage to track a resonance frequency of the cleaning transducer
Data Source
AI summary
Sensors may incorporate ultrasonic cleaning device controllers and methods to keep their exposed surfaces free from water, ice, and other adherent substances. One illustrative controller includes a driver configured to drive a transducer with a periodic waveform having voltage pulses and high impedance intervals repeating at a drive frequency. The controller may also include a receiver configured to measure a high impedance voltage of the transducer during the high impedance intervals. The controller may further include control logic configured to adjust the drive frequency using the high impedance voltage to track a resonance frequency of the transducer. Some implementations may use diagnostic bursts with lower voltage pulse magnitudes for tracking and cleaning bursts with higher voltage pulse magnitudes for cleaning. Duty cycle fading may be employed to prevent voltage overshoots after each burst.