Elevator Motor Position Deviation for Loading State Determination
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Solution Overview
Problem
Existing elevator systems face inaccuracies in determining the loading state due to individual weight variations and measuring errors from load-weighing sensors, leading to imbalanced forces and impaired ride comfort and accuracy in stopping at floors.
Innovation Solution
Determining the loading state of an elevator system based on the position deviation of the elevator motor, using a motor drive with a speed reference and positive feedback of torque, which compensates for imbalances and eliminates the need for separate load-weighing sensors, thereby improving accuracy and ride comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If load-weighing sensors are used to determine the loading state, then the loading state can be measured, but measuring errors occur that impair ride comfort and stopping accuracy
Solution Approach 1:
The patent replaces the mechanical load-weighing sensor system with an electrical measurement system. Instead of using physical sensors on the elevator car floor or ropes to measure load weight, the invention uses a motor drive system with encoder to measure the position deviation of the motor shaft during acceleration and deceleration phases. This substitution eliminates the measuring errors inherent in mechanical sensors while providing more reliable data for controlling motor torque, thereby improving both ride comfort and stopping accuracy.
2Adaptability or versatility
If individual weight differences of elevator car and counterweight are present, then the position of equilibrium varies, but this causes imbalance in the elevator system
Solution Approach 1:
The patent implements a self-service mechanism where the system automatically determines and compensates for individual weight variations without requiring manual adjustment or external intervention. The motor drive system performs measurement cycles during operation to determine the actual position deviation caused by specific weight differences between the elevator car and counterweight. Based on these measurements, the system automatically calculates and applies compensation values to the acceleration and deceleration profiles, thereby maintaining loading balance and equilibrium position despite individual variations in component weights.
3Measurement precision
If the position deviation of the elevator motor is used to determine loading state, then accuracy and speed of determination improve, but the system complexity increases
Solution Approach 1:
The patent applies the universality principle by making the motor drive system perform multiple functions. The same motor drive system with encoder that controls motor operation also serves as the measurement device for determining loading state. The encoder already present for motor control is utilized to measure position deviation during acceleration and deceleration phases. This multi-functional approach allows the system to achieve high measurement precision for loading state determination without adding separate dedicated measurement devices, thereby avoiding excessive system complexity while improving accuracy.
Data Source
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AI summary
The invention relates to a determination (1 ) of the loading state of an elevator system and also to a method for determining the loading state of an elevator system. The elevator system comprises an elevator car (2) and also a motor drive (3) for moving the elevator car. In the invention the loading state of the elevator system is determined on the basis of the position deviation (4) of the elevator motor that occurs during the determination of the loading state.