Ultrasonic Sensor Capacitance Mapping for Adhesion Type Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ultrasonic sensors struggle to differentiate between partial and entire adhesion of foreign substances on the vibration surface, such as water and snow, which affects obstacle detection accuracy due to similar capacitance changes.
Innovation Solution
The ultrasonic sensor incorporates a plurality of variable capacitances formed by sensor electrodes on the microphone housing's surface, measuring individual and total capacitance values to determine the type and position of foreign substance adhesion, utilizing the difference in relative dielectric constants to differentiate between partial and entire adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single capacitance sensor is used to detect foreign substance adhesion, then the device complexity is reduced, but the measurement precision cannot differentiate between partial and entire adhesion types
Solution Approach 1:
The bottom surface is divided into multiple measurement regions, each with its own sensor electrode pair, allowing independent capacitance measurement for each region. This segmentation enables the system to distinguish between partial adhesion (affecting only some regions) and entire adhesion (affecting all regions) by analyzing the spatial distribution of capacitance changes across multiple measurement points.
Solution Approach 2:
Different regions of the bottom surface are assigned different sensor electrode configurations tailored to their specific detection needs. By measuring capacitance changes locally at multiple positions rather than using a single global sensor, the system achieves precise differentiation between partial and entire adhesion types based on the spatial pattern of capacitance variations.
2Measurement precision
If multiple sensor electrodes are added to detect adhesion type, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The multiple sensor electrode pairs serve multiple functions: they detect the presence of foreign substance adhesion, determine the type of adhesion (partial vs. entire), and identify the specific foreign substance material. By using the same electrode structure for these different detection purposes, the system achieves high measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The system utilizes changes in capacitance values as the key parameter to detect and differentiate adhesion types. By measuring capacitance at multiple positions and analyzing the pattern of changes, the system can identify foreign substance type and adhesion extent. This parameter-based approach avoids complex mechanical or optical structures, maintaining relatively simple device architecture while achieving high precision.
3Measurement precision
If the sensor electrodes are placed on the vibration surface, then the detection accuracy for adhesion is improved, but the vibration properties of the microphone housing are interfered with
Solution Approach 1:
The sensor electrodes are placed on the bottom surface but are electrically isolated into separate measurement regions. This segmentation allows the electrodes to be positioned on the vibration surface for accurate adhesion detection while the regional isolation minimizes their electrical interference with the vibration properties, as each region can be measured independently without affecting the overall vibration characteristics.
Solution Approach 2:
The bottom surface acts as an intermediary structure that allows sensor electrodes to be positioned close to the vibration surface for accurate detection while maintaining electrical isolation. The capacitance measurement mechanism serves as an intermediary detection method that can sense adhesion effects without requiring direct mechanical contact that would interfere with vibration properties.
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
Enables accurate detection of foreign substance adhesion, specifying whether it is partial or entire, and identifying the type, thereby improving obstacle detection reliability by minimizing interference with vibration properties.
Implementation Method 1
a plurality of variable capacitances defined between a plurality of sensor electrodes disposed on a first surface of a bottom of the microphone housing, each of the plurality of variable capacitances having a capacitance value which changes in response to adhesion of a foreign substance to the first surface
Implementation Method 2
utilizing the difference in relative dielectric constants to differentiate between partial and entire adhesion
Implementation Method 3
a piezoelectric vibration element converting an electrical signal into a vibration and converting a vibration into an electrical signal
Implementation Method 4
The ultrasonic sensor generates ultrasonic waves by causing the vibration portion to be subjected to ultrasonic vibration when the microphone is energized
Implementation Method 5
converting a vibration into an electrical signal
Data Source
AI summary
An ultrasonic sensor includes an adhesion sensor detecting adhesion of a foreign substance to a first surface of a bottom of a microphone housing. The adhesion sensor includes: a plurality of variable capacitances defined between a plurality of sensor electrodes disposed on the first surface of the bottom, each of the variable capacitances having a capacitance value which changes in response to adhesion of a foreign substance to the first surface; and an adhesion detection unit configured to measure an individual capacitance value which is a capacitance value of each of the variable capacitances and a total capacitance value which is a total of capacitance values of all the variable capacitances to determine, based on the individual capacitance value and the total capacitance value, whether a foreign substance adheres to the first surface, and, when it is determined that a foreign substance adheres, specify a type of the foreign substance.