Ultrasonic Object Detection With Dual Receiver Signal Summation
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Solution Overview
Problem
Existing object detectors using ultrasonic sensors are susceptible to direct sound waves that are received without being reflected off the object, leading to inaccurate detection and inability to utilize echo signals during the reception of direct waves, especially with chirp waves of long duration, and limiting short-range detection.
Innovation Solution
The object detector employs multiple wave receivers arranged with a predetermined distance difference to minimize the influence of direct waves by optimizing the layout, allowing simultaneous reception of direct and echo waves, using a thermophone as the wave transmitter and MEMS microphones as receivers, and employing signal processing to generate an analytic signal for accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single wave receiver is used to receive sound waves, then the device complexity is reduced, but the detection precision deteriorates due to susceptibility to direct waves and inability to distinguish echo signals
Solution Approach 1:
The patent divides the wave reception function into multiple receivers (first wave receiver and second wave receiver) positioned at different locations. This segmentation allows the system to receive both direct waves and echo waves simultaneously, improving detection precision by enabling distinction between direct and reflected sound waves through spatial separation
Solution Approach 2:
The patent introduces a spatial dimension to the wave reception system by positioning receivers at different distances from the wave transmitter. The second wave receiver is located farther away than the first, creating a distance-based dimensional difference that enables the system to differentiate between direct waves (received first by closer receiver) and echo waves (received by both receivers with time delay)
2Productivity
If the wave reception is forbidden during direct wave transmission period, then the harmful effect of direct waves is eliminated, but the productivity deteriorates due to inability to utilize echo signals during this period
Solution Approach 1:
The patent enables continuous wave reception by both the first and second wave receivers throughout the entire transmission period, including when direct waves are present. This eliminates the need to forbid reception during direct wave transmission, allowing continuous utilization of echo signals and improving detection efficiency and productivity
Solution Approach 2:
The patent introduces the second wave receiver as an intermediary element that, due to its greater distance from the transmitter, receives direct waves with a time delay. This allows the first wave receiver to capture echo signals from nearby objects while the second wave receiver simultaneously captures both direct and echo waves, enabling the system to process useful echo information continuously without interruption
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 detector achieves high-accuracy object detection by minimizing the impact of direct waves, enabling continuous reception of echo signals and reducing signal noise, thus improving detection precision and range.
Implementation Method 1
capable of detecting an object through transmission and reception of sound waves
Data Source
AI summary
An object detector includes a wave transmitter to transmit a modulated wave in a predetermined frequency range to an object, a first wave receiver to receive sound waves and to generate a first wave reception signal indicative of the reception of the sound waves, a second wave receiver to receive sound waves and to generate a second wave reception signal indicative of the reception of the sound waves, an adder to generate a third wave reception signal by adding the first and second wave reception signals, and a controller to detect the object based on the third wave reception signal by causing the wave transmitter to transmit the modulated wave. The second wave receiver is farther from the wave transmitter than the first wave receiver. A fluctuation range of the third wave reception signal is not greater than a fluctuation range of the first wave reception signal.