Ultrasonic Sensor Self-Cleaning Using Resonant Piezoelectric Bursts
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Solution Overview
Problem
Ultrasonic sensors in vehicles are prone to failures due to obstructions such as dirt, mud, snow, or ice, leading to degraded performance and increased manufacturing costs for cleaning mechanisms, with existing systems often omitting obstructed data to maintain reliability, thereby degrading overall system performance.
Innovation Solution
Incorporating a sensor controller that uses a piezoelectric transducer to generate acoustic bursts for both obstacle detection and self-cleaning, employing long bursts at resonant frequency to remove obstructions autonomously, without additional components, and monitoring internal temperature to manage heating and ensure sensor integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensor cleaning mechanisms (jets of air, water, heating, ultrasonic cleaning) are implemented, then sensor reliability is improved, but manufacturing cost increases
Solution Approach 1:
The ultrasonic sensor performs self-cleaning by utilizing its own transducer to generate cleaning vibrations. The controller activates the transducer in a cleaning mode that produces high-frequency vibrations to remove contaminants from the sensor surface, eliminating the need for external cleaning mechanisms and reducing manufacturing costs while maintaining reliability
Solution Approach 2:
The patent employs mechanical vibration through the piezoelectric transducer to achieve cleaning. By driving the transducer at resonant frequencies, the sensor generates strong vibrations that mechanically remove dirt, snow, and ice from the sensor surface, providing an effective cleaning solution without additional components
2Object-affected harmful factors
If ultrasonic cleaning is used for sensor maintenance, then cleaning effectiveness is improved, but device complexity increases
Solution Approach 1:
The ultrasonic transducer serves dual functions: it acts as both the sensing element for distance measurement and the cleaning element for removing contaminants. The controller manages different operational modes (sensing mode and cleaning mode) by adjusting the drive parameters of the same transducer, thereby eliminating the need for separate cleaning components and reducing device complexity
3Measurement precision
If the sensor operates continuously to detect obstacles, then measurement precision is maintained, but vulnerability to obstructions increases
Solution Approach 1:
The controller implements periodic cleaning cycles by alternating between sensing operations and cleaning operations. During normal sensing, the transducer operates at low power to maintain measurement precision. When contamination is detected or at scheduled intervals, the controller activates cleaning mode with high-power vibrations, then returns to sensing mode, creating a periodic cycle that maintains both precision and reliability
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 self-cleaning functionality enhances sensor reliability by autonomously removing obstructions, maintaining performance without additional costs, and allowing continuous operation with minimal interference to other sensors, thus improving the robustness of ultrasonic sensing systems.
Implementation Method 1
driving a piezoelectric transducer to generate a short acoustic burst for obstacle detection or distance measurement
Implementation Method 2
operating to clean the sensor by driving the piezoelectric transducer to generate a long acoustic burst at a resonant frequency of the piezoelectric transducer
Implementation Method 3
generate a long acoustic burst at a resonant frequency
Implementation Method 4
obtaining a receive signal to monitor for reflections of the short acoustic burst
Data Source
AI summary
Ultrasonic sensors, sensor controllers, and sensor control methods are provided with self-cleaning functionality. An illustrative method includes: driving a piezoelectric transducer to generate a short acoustic burst for obstacle detection or distance measurement; obtaining a receive signal to monitor for reflections of the short acoustic burst; and operating to clean the sensor by driving the piezoelectric transducer to generate a long acoustic burst at a resonant frequency of the piezoelectric transducer. The method may be implemented by a sensor controller having a transmitter configured to drive the piezoelectric transducer, a receiver coupled to the piezoelectric transducer and a microphone to detect a reflection of the acoustic burst within a measurement interval associated with the acoustic burst; and a microcontroller configured to control a length of the acoustic burst. The sensor controller may be incorporated into a sensor that also includes a piezoelectric transducer and optionally includes one or more microphones.