Ultrasonic Sensor Multi-Filter Outputs for Motion Differentiation
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Solution Overview
Problem
Ultrasonic proximity switches with uniform filter criteria struggle to accurately detect object movement and differentiate between stationary and moving objects, leading to unreliable sorting and counting in complex applications such as materials handling and traffic engineering.
Innovation Solution
The ultrasonic sensor employs multiple independent filter stages with distinct filter criteria and threshold values, enabling the detection of dynamic processes and movement by generating differentiated binary signals, allowing for more detailed information to be transmitted to a programmable logic controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a uniform filter criterion is used in the filter stage, then the device complexity is reduced, but the measurement precision and reliability of detecting object movement deteriorate
Solution Approach 1:
The filter stage is segmented into multiple independent filter stages (first filter stage, second filter stage, etc.), each with its own filter criterion. This segmentation allows different aspects of the echo signal to be evaluated separately, improving the ability to detect object movement while maintaining manageable device complexity through modular design.
Solution Approach 2:
Each filter stage is assigned a specific filter criterion tailored to detect particular characteristics of the echo signal. For example, one filter stage may use amplitude comparison while another uses stability comparison. This local quality approach ensures that each part of the system performs a specialized function, enhancing overall measurement precision.
2Reliability
If multiple filter stages with independent filter criteria are implemented, then the measurement precision and reliability of detecting object movement improve, but the device complexity increases
Solution Approach 1:
The complex detection task is segmented into multiple filter stages, each handling a specific aspect of signal evaluation. This division improves reliability by ensuring that no single filter criterion dominates the detection process, while the modular segmented structure keeps device complexity manageable.
Solution Approach 2:
The multiple filter stages work together as an integrated system to achieve multi-functionality. The first filter stage evaluates one aspect of the echo signal, the second filter stage evaluates another aspect, and their combined results provide comprehensive object detection and movement detection capabilities, enhancing reliability through functional redundancy and complementarity.
3Ease of operation
If only one filter level is used, then the ease of operation is maintained, but the ability to differentiate between stationary and moving objects deteriorates
Solution Approach 1:
The information extraction process is segmented into multiple filter stages, each capturing different characteristics of the echo signal. This segmentation preserves movement information that would be lost in a single filter level, while the systematic segmented approach maintains ease of operation through consistent modular design.
Solution Approach 2:
The system transitions from a single-dimension filter evaluation to multi-dimensional evaluation by adding multiple filter stages with different criteria. This dimensional expansion allows differentiation between stationary and moving objects without significantly complicating operation, as each additional dimension adds complementary information rather than 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 allows for the reliable detection of object movement and differentiation between stationary and moving objects, enhancing the accuracy of object tracking and monitoring in complex environments by utilizing separate filter stages with adjustable criteria.
Implementation Method 1
an acoustic emission and reception unit (2) which cyclically emits ultrasonic transmission bursts (3a) and detects ultrasonic echo signals (3b) reflected by objects (13, 14 and 15) in an area of a sound beam
Implementation Method 2
The echoes, which are thrown back by the objects located in the area of a sound beam, are detected again by the proximity switch
Implementation Method 3
the emitted sound beams and reflected echoes are subjected to time-of-flight measurements. The propagation times of the reflected echo signals are usually directly proportional to the distance between the objects and the proximity switch
Data Source
Figure 1
Figure 2
AI summary
The sensor (1) has two separate switch outputs (7a, 7b), which are controlled by a processing unit (4). The processing unit executes two separate filter stages (6a, 6b) with an automated filtering criterion and a prescribed threshold value. The processing unit supplies a measuring value (5) to the filter stages in a cyclic manner, where the measuring value produces a binary signal when obtaining the threshold value by the filtering criterion. The processing unit activates the switch outputs. Amplitude of the measuring value is evaluated at the filtering criterion of the filter stages.