Elevator Counterweight Calibration Using Motor Current and Height Data
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Solution Overview
Problem
Existing methods for adjusting elevator counterweights are time-consuming and prone to inaccuracies due to varying friction conditions, requiring multiple trials to achieve equilibrium, and there is a need for a more precise and simplified method to determine the required adjustments.
Innovation Solution
A method involving controlled test runs of the elevator car with and without load, using current and height measurement data to calculate a calibration function that determines the necessary adjustment for counterweight balance, allowing for precise adjustment without trial and error.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple trial adjustments of counterweight are performed to achieve equilibrium, then the counterweight can be balanced with the car, but the adjustment process becomes very time-consuming
Solution Approach 1:
The patent applies preliminary action by measuring the current drawn by the motor during a single test run with the car in an unloaded state and in a state with a known test weight. These preliminary measurements are used to calculate the conversion factor and determine the precise counterweight setting in advance, eliminating the need for multiple trial adjustments and significantly reducing adjustment time while maintaining high accuracy.
2Manufacturing precision
If gradual weighting or lightening of the car with counterweights is performed to find equilibrium, then the counterweight can be adjusted, but the result becomes inaccurate due to varying friction conditions
Solution Approach 1:
The patent replaces the mechanical trial-and-error adjustment method with an electrical measurement system. By measuring the current drawn by the motor during controlled test runs and using this electrical data to calculate the counterweight setting, the system eliminates the influence of varying friction conditions that affect mechanical equilibrium methods, thereby achieving higher precision in counterweight setting.
3Measurement precision
If several trials with different counterweights are conducted to determine precise weight, then equilibrium can be achieved, but the procedure becomes complex and time-consuming
Solution Approach 1:
The patent applies self-service by enabling the control device to automatically perform measurements, calculate the conversion factor, and determine the precise counterweight setting without requiring manual intervention for multiple trials. The system uses a single test run with an unloaded car and a single test run with a known weight to self-determine the optimal counterweight configuration, simplifying the procedure while maintaining high measurement precision.
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 method significantly simplifies and enhances the accuracy of counterweight adjustment, reduces measurement inaccuracies due to friction fluctuations, and minimizes the need for reloading the elevator car, thereby reducing overall effort and ensuring precise equilibrium.
Implementation Method 1
Receiving current measurement data, indicating the current flowing through the electric motor as measured by a current measuring device during the movement of the car
Implementation Method 2
height measurement data, indicating the height of the car relative to the first and/or second position as measured by a height measuring device during the movement of the car
Implementation Method 3
an electric motor for driving the car
Implementation Method 4
a counterweight that is connected to a car via suitable lifting means and serves to reduce the forces required to raise or lower the car
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a method for adapting a counterweight (106) of an elevator system (100), having the steps of: generating control commands for actuating an electric motor (110) such that an elevator car (104) which is coupled to the counterweight carries out at least one first, second, third, and fourth test run, wherein the elevator car is moved from a first position into a second position in each of the first and third test runs and from the second position into the first position in each of the second and fourth test runs, and the elevator car is loaded with a weight (126) in the third and fourth test runs and is not loaded with the weight in the first and second test runs; receiving current measurement data, which indicates the current flowing through the electric motor, said current being measured by a current measuring device (124) during the movement of the elevator car, and height measurement data, which indicates the height of the elevator car relative to the first and/or second position, said height being measured by a height measuring device (122) during the movement of the elevator car, in multiple successive time steps in each test run; calculating at least one parameter of a calibration function, which defines a relationship between the current, the height, and the weight, using the current measurement data and the height measurement data received in different test runs in order to obtain at least one calibration value; and calculating an adaptation value using the at least one calibration value in order to adapt the counterweight so that the counterweight is in equilibrium with the elevator car (104).