Ultrasonic Object Position Analysis With Phase-Difference Filtering
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Solution Overview
Problem
Ultrasonic sensors on mobile devices face challenges in accurately detecting objects in a specific direction due to broad wave directionality and interference from reflected waves from non-target directions, leading to decreased accuracy and increased processing load.
Innovation Solution
An object position analysis device using a speaker and a plurality of microphones with a data processing unit that selects reflected waves with a high correlation to a predefined phase difference from the target direction, allowing for accurate analysis of object positions in that direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If ultrasonic waves are transmitted with broad directionality to detect objects in all directions, then the coverage area for object detection is improved, but reflected waves from non-target directions enter the microphone as noise, decreasing detection accuracy
Solution Approach 1:
The patent applies local quality by making different parts of the ultrasonic wave transmission have different directional characteristics. The front surface of the speaker has higher transmission intensity toward the front direction, while side and rear surfaces have reduced transmission. This creates localized directional control where the front area maintains broad coverage for detection while side and rear areas minimize noise reflection into the microphone.
Solution Approach 2:
The patent implements asymmetry in the speaker's ultrasonic wave transmission characteristics. The front surface is designed to transmit waves primarily in the forward direction with intentional attenuation of side and rear transmissions. This asymmetric transmission pattern ensures that reflected waves from the front direction (target objects) are strong while reflected waves from side and rear directions (noise sources) are weakened, resolving the contradiction between coverage and accuracy.
2Productivity
If the robot travels at high speed, then productivity is improved, but the processing time for analyzing reflected waves must be reduced, making it difficult to filter out noise from non-target directions
Solution Approach 1:
The patent applies preliminary action by pre-configuring the speaker's ultrasonic wave transmission characteristics before detection begins. The front surface is designed to inherently transmit waves with directional bias toward the front, and the side/rear surfaces are designed to transmit with reduced intensity. This preliminary directional configuration means that when reflected waves are received during high-speed travel, the noise from non-target directions is already attenuated, reducing the processing burden and enabling faster analysis without sacrificing accuracy.
3Measurement precision
If a horn is attached to the speaker to increase directionality, then noise from non-target directions is reduced, but the noise reduction effect is limited and insufficient for adequate accuracy
Solution Approach 1:
The patent applies segmentation by dividing the speaker's front surface into multiple independent emission units (first, second, third, and fourth emission units). Each unit can be controlled independently to transmit ultrasonic waves with specific directional characteristics. This segmentation allows precise control over the transmission pattern, achieving superior noise reduction compared to a simple horn attachment, while the modular unit structure keeps the overall design manageable and not excessively complex.
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 device effectively filters out non-target direction reflections, enabling quick and precise object detection in the intended direction, reducing processing load and maintaining high travel speeds.
Implementation Method 1
An ultrasonic sensor transmits ultrasonic pulse waves and receives reflected waves from an object
Implementation Method 2
receives reflected waves from an object. The distance to the object can be calculated by measuring the time from the transmission to the reception of the pulse wave
Implementation Method 3
a plurality of microphones that input reflected waves from the sound pulse signal output by the speaker
Implementation Method 4
The distance to the object can be calculated by measuring the time from the transmission to the reception of the pulse wave, and multiplying the measured time by the speed of sound
Implementation Method 5
multiplying the measured time by the speed of sound
Implementation Method 6
The direction of the object can be calculated using algorithms such as the beamforming method, MUSIC, and the like, using a microphone array in which a plurality of microphones that output ultrasonic waves are arranged
Data Source
AI summary
Provided is an object position analysis device that analyzes the position of an object in a specific analysis target region. The device includes: a speaker that outputs a sound pulse signal; a plurality of microphones that input reflected waves from the sound pulse signal output by the speaker; and a data processing unit that analyzes the reflected waves input by the plurality of microphones and analyzes a position of an object that has reflected the sound pulse signal. The data processing unit: selects, as an analysis target reflected wave, a reflected wave, among the reflected waves input by the plurality of microphones, having a phase difference that has a high correlation with a phase difference of a sound pulse signal from an analysis target direction defined in advance; and analyzes a position of an object in an analysis target region near the analysis target direction through analysis processing on the analysis target reflected wave selected.