Position Encoder Failure Detection via Sensor Array Evaluation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional position encoder systems fail to reliably detect failures in sensors or signal processing circuits, which can lead to erroneous measurements, especially in critical applications like automotive or security systems, where undetected malfunctions can be critical.
Innovation Solution
A failure detection concept that uses a position encoder arrangement with evenly distributed sensors to generate sensor values for both position determination and functional safety evaluation. This involves comparing sensor values against a threshold to determine a coarse position and generate error flags, allowing for parallel failure detection with conventional position determination, and compensating for stray fields and external influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional position encoder systems are used for position determination, then position measurement function is provided, but failure detection capability is insufficient
Solution Approach 1:
The sensor values from the position encoder are used for multiple purposes: both for determining the position of the movable object and for detecting failures in the sensor system. The evaluation unit performs both position calculation and failure detection using the same sensor inputs, making the system multi-functional without adding separate detection hardware.
Solution Approach 2:
The system performs preliminary failure detection by comparing sensor values against expected patterns before critical failures occur. The evaluation unit continuously monitors sensor signals for anomalies that indicate potential failures, enabling early detection and preventing erroneous position measurements.
2Reliability
If sensor values are used only for position determination, then measurement function is simple, but failure status cannot be detected
Solution Approach 1:
The evaluation unit implements feedback by continuously comparing sensor values against expected patterns and generating failure status information. The system monitors the consistency of sensor readings with the known geometrical distribution of sensors, providing ongoing feedback about system health and detecting deviations that indicate failures.
Solution Approach 2:
The system establishes expected sensor value patterns based on the known geometrical distribution of sensors before operation. During operation, actual sensor values are compared against these pre-established patterns to detect failures, enabling early warning before critical errors occur.
3Measurement precision
If a malfunctioning sensor continues to deliver signals, then position measurement may be erroneous, but the error remains undetected in conventional systems
Solution Approach 1:
The evaluation unit continuously monitors sensor signals for consistency with the known geometrical distribution of sensors. When a malfunctioning sensor delivers erroneous signals, the feedback mechanism detects the deviation from expected patterns and generates a failure status, preventing undetected erroneous measurements.
Solution Approach 2:
The system pre-establishes the expected spatial relationships and signal patterns based on the known geometrical distribution of sensors. This preliminary knowledge enables the system to detect when actual sensor readings deviate from expectations, indicating malfunctions before they cause critical measurement errors.
Data Source
AI summary
A position encoder arrangement is configured to detect the position of a movable source based on a source field, which is a magnetic field or an electric field, emitted by the source. The position encoder arrangement includes a number of sensor elements that are evenly distributed and each is configured to provide a sensor value based on the source field at the sensor element's location. The arrangement further includes an evaluation unit that is configured to determine a fine position value for the position of the movable source, and to determine from the sensor values a trustworthiness of the fine position value and/or an error flag indicating whether a failure status of the position encoder arrangement is present.