TOF Sensor Test Emitter Self-Verification
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Solution Overview
Problem
Existing sensors for monitoring areas lack an effective method to self-test and ensure the correct operation of their functional units, particularly the receiver and evaluation device, which can lead to inaccuracies in distance measurement and 3D imaging.
Innovation Solution
A sensor system incorporating a test transmitter, receiver, evaluation device, memory, and comparison device that uses a test signal to assess the distance value and output a safety signal if it differs from an expected value, with features like synchronization and modulation to enhance accuracy and reliability, allowing for self-testing and improved operational verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a test transmitter is added to enable self-testing of the sensor, then the reliability of the sensor is improved, but the device complexity increases
Solution Approach 1:
The test transmitter is integrated into the sensor housing and uses the same receiver and evaluation device as the main transmitter, allowing the sensor to perform both its primary monitoring function and self-test function using shared components. This multi-functionality approach enables reliability improvement without proportionally increasing overall system complexity.
Solution Approach 2:
A comparison device is introduced as an intermediary component that automatically compares the measured distance value from the test signal with a stored expectation value, and generates a safety signal when deviations exceed a tolerance. This intermediary automates the verification process, improving reliability while keeping the added complexity manageable through a single dedicated component.
2Measurement precision
If the test transmitter directly irradiates the receiver, then the measurement precision is improved, but the device complexity increases due to additional optical components
Solution Approach 1:
The test transmitter and main transmitter are merged into a single housing with shared optical components including the receiver. The test transmitter uses the same receiver optical system and evaluation device as the main transmitter, combining multiple functions into a unified structure that reduces overall complexity while maintaining measurement precision.
Solution Approach 2:
The test transmitter creates a simplified copy of the main measurement path by transmitting test signals that follow the same optical path to the receiver, allowing verification of the measurement system without requiring a completely separate test apparatus. This copying approach ensures measurement precision while minimizing additional complexity.
3Loss of time
If the sensor performs self-testing with test signals, then the loss of time for manual testing is reduced, but the productivity decreases due to test signal transmission time
Solution Approach 1:
The test transmitter operates periodically by transmitting test signals at predetermined intervals rather than continuously. This periodic operation allows the sensor to perform self-testing without constantly interrupting its primary monitoring function, reducing the impact on productivity while still eliminating the need for manual testing.
Solution Approach 2:
The sensor maintains continuous monitoring of the monitoring area through the main transmitter while integrating self-testing operations into the same operational framework. The test signals are transmitted during predetermined intervals without completely stopping the useful monitoring action, ensuring both time savings from automated testing and minimal impact on overall productivity.
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 sensor system enables thorough self-testing, ensuring the correct operation of its units and providing accurate distance measurements and 3D imaging by comparing received test signal data with expected values, thereby maintaining operational integrity and accuracy.
Implementation Method 1
The transmitter (20) is designed to transmit radiation into the monitoring area, which radiation is partially reflected to the sensor again after reflection at an object in the monitoring area
Implementation Method 2
The evaluation device (50) is configured for ascertaining a distance value on the basis of the transit-time delay or the phase delay of a modulation between the radiation transmitted by the transmitter or test transmitter and the radiation received by the receiver
Implementation Method 3
the radiation of the transmitter and/or of the test transmitter is modulated, in particular intensity modulated, in particular modulated with 20 MHz
Data Source
AI summary
A sensor for monitoring a monitoring area having a transmitter for transmitting radiation into the monitoring area for reflection at an object in the monitoring area, a test transmitter for transmitting a test signal comprising radiation, a receiver for receiving the radiation of the transmitter that is reflected at the object or the radiation of the test transmitter, and an evaluation device for ascertaining a distance value on the basis of the delay in the transit time or the phase of a modulation between the transmitted and received radiation of the sensor. The sensor further comprises a memory for storing an expectation value for the expected distance value of the received test signal, and a comparison device for comparing a distance value on the basis of the received test signal with the expectation value and for outputting a safety signal on the basis of the comparison.