3D Elevator Car Position Sensing Without Shaft Code Tapes
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Solution Overview
Problem
Existing elevator systems face challenges in accurately determining the position of an elevator car within a shaft while minimizing installation costs and maintaining precision, particularly when the car sways during movement.
Innovation Solution
A 3D sensor, such as a PMD sensor, is used in conjunction with a marker element that emits electromagnetic radiation, allowing the evaluation unit to determine the elevator car's position based on measured distances and intensity parameters, eliminating the need for extensive shaft-mounted components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a code tape extending over the entire elevator shaft is used to determine position, then measurement precision is improved, but device complexity and installation cost increase
Solution Approach 1:
The invention extracts the measurement function from a complex shaft-wide code tape system and concentrates it into a simple marker element attached to the elevator car. The 3D sensor mounted on the car reads only the local marker position, eliminating the need for extensive shaft infrastructure while maintaining position determination capability.
Solution Approach 2:
Instead of using a physical code tape spanning the entire shaft, the invention uses a digital copy of position information encoded in a compact marker element. The marker contains position data that can be read and interpreted by the 3D sensor, creating a virtual representation of shaft position without physical shaft modifications.
2Measurement precision
If extensive shaft-mounted components are installed to ensure accurate position determination, then measurement precision is improved, but ease of manufacture and installation deteriorate
Solution Approach 1:
Conventionally, the sensor is mounted in the shaft and reads markers on the moving car. This invention inverts the approach by mounting the 3D sensor on the moving elevator car and having it read a marker element that is read from the shaft infrastructure. This inversion simplifies installation since the sensor moves with the car rather than requiring shaft modification at multiple levels.
Solution Approach 2:
The elevator car itself serves as the mounting platform for the 3D sensor, utilizing the car's existing structure and movement mechanism. The system is self-contained on the moving vehicle rather than requiring external shaft infrastructure, making the system easier to manufacture and install.
3Adaptability or versatility
If the elevator car sways during movement, then adaptability to real-world conditions is improved, but measurement precision deteriorates
Solution Approach 1:
The system accounts for the dynamic nature of elevator car movement including swaying. The 3D sensor and marker element configuration is designed to maintain accurate position determination despite car motion, with the sensor capable of tracking the marker position even when the car body moves laterally or rotates slightly during operation.
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 provides a cost-effective and precise method to determine the elevator car's position within the shaft, ensuring accurate stopping and movement control without requiring additional shaft installations.
Implementation Method 1
The 3D sensor has a transmitter for emitting electromagnetic radiation and is configured to determine the time of flight of the electromagnetic radiation emitted by the transmitter and reflected by the detected object for each sensor cell
Implementation Method 2
The marking element is designed to actively emit electromagnetic radiation
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 movably arranged 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) that actively emits electromagnetic radiation. 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) and a region around the marking element (36) as an object. The analysis unit (30) is configured to determine those sensor cells that detect the marking element (36). The analysis unit (30) is additionally configured to determine the position of the elevator cab (12) on the basis of the determined distances of said sensor cells and/or of sensor cells located in a zone adjoining the sensor cells in question, from the detected object.