Elevator Stuck Detection Through Correction Torque Monitoring
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Solution Overview
Problem
Existing elevator systems lack a reliable and rapid method to detect stuck situations, which can lead to dangerous situations due to uncontrolled movement of the elevator car or counterweight, potentially causing damage or injury.
Innovation Solution
A method involving a control device that monitors correction torque based on load and speed signals to detect stuck situations by comparing torque differences against predefined criteria, allowing for rapid and reliable detection without additional electronic safety devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no additional electronic safety devices are used, then device complexity is reduced, but reliability of stuck situation detection deteriorates
Solution Approach 1:
The control device is designed to perform both normal elevator operation control and stuck situation detection functions using the same existing sensors and processing units. The control device utilizes existing load signals and speed signals for their primary control purposes while simultaneously analyzing these same signals for stuck situation detection, making the control device multi-functional and eliminating the need for separate safety devices.
Solution Approach 2:
The system uses its own existing operational data (load signals and speed signals) to detect stuck situations. The control device monitors parameters that are already being measured for normal operation and identifies stuck conditions through abnormal patterns in these self-generated data streams, making the system self-diagnostic without requiring external safety equipment.
2Device complexity
If existing sensors are used for both control and safety detection, then device complexity is reduced, but measurement precision for safety detection deteriorates
Solution Approach 1:
The system changes the parameter being monitored from individual sensor readings to the relationship between multiple parameters. Instead of relying on a single precision measurement, the stuck detection analyzes the correlation and consistency between load signal and speed signal, detecting stuck conditions when these parameters exhibit physically impossible relationships (such as load indicating movement in one direction while speed indicates movement in the opposite direction).
Data Source
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AI summary
The invention provides a method for identifying a situation of being stuck in a lift installation (20). The lift installation (20) has a lift shaft (22), a car (24) which is arranged in the lift shaft (22), a counterweight (26) which is coupled to the car (24) by way of carrying means (28), an electric motor (30) which has a drive pulley (32) which can be rotated by means of the electric motor (30), over which the carrying means (28) runs and by means of which the carrying means (28) can be moved, so that the car (24) and the counterweight (26) can be displaced vertically by means of operating the electric motor (30), and a brake (34) by means of which the car (24) and/or the counterweight (26) can be braked and/or stopped. The method comprises: receiving a load signal which is representative of a weight of a load (46) which is located in the car (24) and is intended to be transported by means of the car (24); determining a preliminary torque (TM REF FF) depending on the load signal; receiving a speed signal (vk_act) which is representative of an actual speed of the car (24); monitoring a correction torque (TM REF PID) over a specified monitoring time period, the correction torque (TM REF PID) being determined depending on the speed signal (vk_akt) and a specified reference speed (vk_ref) such that the actual speed of the car (24) approximates the reference speed (vk_ref); identifying the situation of being stuck, in which the car (24) or the counterweight (26) remains stuck in the lift shaft (22), when the monitored correction torque (TM REF PID) meets at least one specified criterion; and carrying out a specified safety measure when the situation of being stuck is identified.