3D Elevator Car Position Sensing With Marker Verification
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Solution Overview
Problem
Existing elevator systems face challenges in reliably determining the position of the elevator car within the shaft, particularly when limit switches are not used, which can lead to inaccurate stopping and potential safety issues.
Innovation Solution
A 3D sensor system with a marker element, such as a reflector or infrared LED, is used to determine the elevator car's position within the shaft, ensuring reliable detection by continuously checking for the marker element, and entering an error mode if detection fails, thereby meeting Safety Integrity Level (SIL) 3 requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a 3D sensor system with continuous detection checking is implemented, then the reliability of position determination is improved, but the device complexity increases
Solution Approach 1:
The evaluation unit continuously checks whether the 3D sensor detects the marker element and puts the system into an error mode as soon as the check fails. This feedback mechanism ensures reliable position determination by continuously monitoring detection status and responding appropriately, resolving the contradiction between reliability improvement and device complexity.
Solution Approach 2:
A marker element is introduced as an intermediary between the 3D sensor and the elevator car. The marker element reflects or emits signals that the 3D sensor detects to determine the elevator car's position. This intermediary simplifies the detection process and improves reliability without significantly increasing overall system complexity.
2Ease of operation
If limit switches are removed from the elevator shaft, then the ease of operation is improved, but the measurement precision deteriorates
Solution Approach 1:
The patent replaces mechanical limit switches with a 3D sensor system that uses optical or electromagnetic fields to detect the marker element. This substitution eliminates the need for physical contact switches in the shaft, improving ease of operation while maintaining measurement precision through continuous non-contact detection of the marker element's position.
Solution Approach 2:
The system changes the detection parameter from mechanical contact (limit switches) to optical/electromagnetic detection (3D sensor detecting marker element). This parameter change allows for continuous position measurement without mechanical components in the shaft, improving ease of operation while preserving measurement precision through accurate distance measurement from the 3D sensor.
3Reliability
If the 3D sensor continuously monitors the marker element, then the reliability is improved, but the use of energy increases
Solution Approach 1:
The evaluation unit performs continuous checking of the marker element detection status at regular intervals rather than requiring constant active monitoring. This periodic action maintains reliability by continuously verifying detection status while reducing energy consumption compared to continuous active sensing, resolving the contradiction between reliability improvement and energy use.
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 system provides a reliable and safe determination of the elevator car's position, minimizing installation effort and ensuring precise operation by restricting or shutting down the elevator if the detection fails, thus enhancing safety and compliance with SIL 3 standards.
Implementation Method 1
The 3D sensor has multiple sensor cells, and the evaluation unit is configured to use measurement data received from the 3D sensor to determine the distance of each sensor cell to a part of an object detected by the 3D sensor
Data Source
Figure 1~3
AI summary
The invention relates to a system (40) and a method for determining the position of an elevator cab (14) of an elevator unit (10), said elevator cab (14) being movable in an elevator shaft (12). The system (40) includes a 3D sensor (26), an analysis unit (30) in communicative connection with the 3D sensor (26), and a marking element (36). The 3D sensor (26) has a plurality of sensor cells, and the analysis unit (30) is configured to determine, by means of measured data received from the 3D sensor (26), a distance of each sensor cell from a part of an object detected by the 3D sensor (26), said part of the object being detected by the particular sensor cell. The 3D sensor (26) is arranged so as to detect the marking element (36) as an object in the normal mode of the system (40). The analysis unit (30) is configured, on the basis of distances of sensor cells (28) from a part of the object detected by the 3D sensor (26), said part of the object being detected by said sensor cells (28): to determine the position of the elevator cab (14) in the elevator shaft (12); to continuously verify whether the 3D sensor (26) detects the marking element (36, 136); and to bring the system (40) into an error mode as soon as the verification yields a negative result.