Optical Sensor Assembly with Redundant Position Evaluation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sensor arrangements for position measurement systems require complex sensor technology and lack high fault tolerance and availability, especially in safety-related applications.
Innovation Solution
A sensor arrangement with a redundant two-channel evaluation unit, comprising two identical computer units connected via a data link, which compares position measurements to ensure accuracy and enters a safe state if measurements differ beyond a tolerance limit, thereby enhancing fault tolerance and availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single evaluation unit is used in the optical sensor, then the device complexity is low, but the fault tolerance and availability are insufficient for safety-related applications
Solution Approach 1:
The evaluation unit is segmented into two independent computer units (first and second computer units), each capable of independently evaluating received signals and determining position measurements. This segmentation enables redundant evaluation paths without requiring a completely complex sensor architecture, thereby improving fault tolerance while controlling device complexity.
Solution Approach 2:
The system changes the operational parameter of having multiple evaluation paths by implementing dual computer units that can operate independently. This parameter change from single to dual evaluation units directly improves reliability and fault tolerance for safety-related applications without fundamentally altering the sensor's core functionality.
2Reliability
If a redundant two-channel evaluation unit is implemented, then fault tolerance and availability improve, but the device complexity increases
Solution Approach 1:
The evaluation unit is divided into two independent computer units with separate signal evaluation paths. Each computer unit independently processes received signals to determine position measurements, creating redundant evaluation channels that improve availability while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The system implements feedback mechanisms where position measurements from both computer units are compared against each other and against expected ranges. This feedback loop enables automatic error detection and validation, improving availability through continuous monitoring while using software-based feedback rather than additional hardware complexity.
3Measurement precision
If position measurements are compared between two computer units, then measurement accuracy and error detection improve, but the processing time and complexity increase
Solution Approach 1:
Both computer units perform position measurement evaluations simultaneously and independently before comparison is needed. This preliminary action ensures that when measurements are compared, both values are already available, reducing the time penalty of dual evaluation and maintaining measurement precision through immediate comparison of pre-computed results.
Solution Approach 2:
The system uses copying by having both computer units independently evaluate the same received signals to produce position measurements. This copying approach enables cross-validation of measurements for improved accuracy while using identical evaluation algorithms, reducing the time overhead compared to having units perform different evaluation tasks.
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 solution provides high fault tolerance and availability, enabling reliable position determination and safe operation in safety-critical applications by correcting or detecting errors in position measurements.
Implementation Method 1
an optical sensor with a transmitter for emitting light beams (3) and a receiver for receiving light beams (3)
Implementation Method 2
means for guiding the transmitted light beams (3) within a scanning range (A)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a sensor arrangement (15) with a position measurement system (17) formed by an arrangement of markers. Each marker's position within the position measurement system (17) is encoded in its position. An optical sensor (1), which is movably arranged relative to the position measurement system (17) and comprises a light beam emitting transmitter (4), a light beam receiving receiver (10), and an evaluation unit (11) for evaluating received signals from the receiver (10), detects markers within a reading field. In the evaluation unit (11), a position measurement value is generated by detecting a position encoded in a marker and the marker's position within the reading field. The evaluation unit (11) has two computing units (12a, 12b) connected via a data connection (14). The received signal is fed to each computer unit (12a, 12b) via an input circuit (13a, 13b).In each computing unit (12a, 12b), the received signal for a detected marker is evaluated, and a position measurement (pA, pB) is determined from it. One computing unit (12a, 12b) sends its position measurement (pA or pB) to the other computing unit (12a, 12b), where the two position measurements (pA, pB) are compared. If the position measurements (pA, pB) match within a predefined tolerance limit, the optical sensor (1) outputs a valid position measurement. Otherwise, the optical sensor (1) enters a safe state.