Ultrasonic Transceivers Overlapping Detection Areas Pinch Protection
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Solution Overview
Problem
Conventional ultrasonic object detection systems face challenges in reliably detecting objects in closable opening areas, particularly due to post-oscillation interference, difficulty in detecting small objects, and issues with ultrasound-absorbing surfaces, as well as temperature variations affecting sound propagation.
Innovation Solution
The use of at least two spatially separate ultrasonic transceivers with overlapping detection areas, employing correlation comparison of echograms in reflection mode and combining reflection and transmission operations to enhance object detection reliability, and incorporating temperature compensation using echogram propagation time changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single ultrasonic transceiver operates in reflection mode, then the device complexity is reduced, but the reliability of object detection deteriorates due to post-oscillation interference and blind range limitations
Solution Approach 1:
The monitoring area is divided into multiple detection zones, each covered by a separate transceiver. This segmentation allows each transceiver to focus on a specific region, reducing the blind range overlap and improving overall detection reliability without requiring a single complex transceiver system.
Solution Approach 2:
Multiple transceivers are combined to work together in a coordinated manner, with their detection areas overlapping to provide comprehensive coverage. The evaluation unit merges the signals from all transceivers, allowing the system to overcome the limitations of individual transceivers and achieve reliable detection throughout the entire monitoring area.
2Ease of operation
If ultrasonic waves are used for object detection, then the ease of operation is improved, but the measurement precision deteriorates due to temperature variations affecting sound propagation speed
Solution Approach 1:
The system continuously monitors the propagation time of ultrasonic waves and uses this information to calculate and apply temperature compensation. The evaluation unit adjusts the reference values based on measured propagation times, creating a feedback loop that maintains measurement precision despite temperature variations.
Solution Approach 2:
The system changes the reference propagation time values dynamically based on temperature conditions. By adjusting these reference parameters according to the actual thermal state of the environment, the system compensates for temperature-induced variations in sound speed and maintains accurate distance measurements.
3Device complexity
If conventional ultrasonic detection is used, then the device complexity is reduced, but the difficulty of detecting and measuring deteriorates due to post-oscillation interference in the near field
Solution Approach 1:
The system uses an intermediary reference echo signal that represents the post-oscillation behavior of the transceiver. By comparing object echoes against this reference, the evaluation unit can distinguish between post-oscillation interference and actual object reflections, enabling detection in the near field without increasing device complexity.
Solution Approach 2:
The system performs preliminary characterization of the transceiver's post-oscillation behavior by recording reference echo signals in advance. These pre-recorded references are then used during operation to identify and filter out post-oscillation interference, allowing the system to detect objects in the near field that would otherwise be obscured.
4Reliability
If multiple transceivers with overlapping detection areas are used, then the reliability of object detection is improved, but the device complexity increases
Solution Approach 1:
Each transceiver is designed to perform multiple functions: detecting objects in its primary detection area, providing reference echo signals for post-oscillation characterization, and serving as a reflective surface for other transceivers. This multi-functionality reduces the need for additional specialized components and simplifies the overall system architecture.
Solution Approach 2:
The transceivers serve themselves by using each other as reflective surfaces to generate reference echo signals. Instead of requiring external reference objects or additional components to characterize post-oscillation behavior, the system uses the transceivers' own structures to provide the necessary reference signals, reducing overall system complexity.
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
This approach significantly improves the reliability of object detection, suppresses interfering signals, and allows for accurate position determination of objects, even in difficult ultrasonic environments and near or blind ranges, while providing effective temperature compensation.
Implementation Method 1
at least two spatially separate ultrasonic transceivers A, B with overlapping detection areas SA, SB that cover the area to be monitored 4 by means of reflected ultrasonic waves
Implementation Method 2
the control/evaluation unit 3 is designed to control the two ultrasonic transceivers A, B to obtain echograms at least in reflection mode
Implementation Method 3
incorporating temperature compensation using echogram propagation time changes
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a device and a method for the ultrasound surveillance of a predetermined area, especially of a closable opening area of a vehicle. The device comprises at least two ultrasound transceivers (A, B) that are interspaced and arranged relative each other such that their detection areas (SA, SB) overlap and cover a surveillance area (4) which can be determined, every transceiver being within the detection area of at least one other transceiver. The device further comprises a control/evaluation unit designed to control the transceivers to obtain echograms for at least a reflective operation and to evaluate the echograms obtained from the transceivers for the presence of objects in the surveillance area, said evaluation comprising a correlating comparison of at least one echogram obtained in the reflective operation of one of the transceivers with at least one echogram obtained in the reflective operation of one of the other transceivers. The device and method are used e.g. for the pinch protection surveillance of closable window, door and/or sunroof areas of vehicles.