Hydraulic Elevator Valve Control via Position Feedback
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Solution Overview
Problem
Hydraulic elevator systems face inaccuracies in elevator car control due to variations in fluid viscosity with temperature changes, which existing monitoring methods do not fully address, increasing complexity and cost.
Innovation Solution
An elevator system with sensors providing real-time status information on the elevator car's position and speed, and a processor that adjusts the valve assembly's operation to correct deviations from predetermined statuses, including altering valve timing to ensure accurate stopping positions and speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow rate monitoring is added to compensate for oil viscosity variations, then positioning accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements feedback control by continuously monitoring the elevator car's actual position using sensor feedback, comparing it with the target position, and adjusting valve assembly operation accordingly. This closed-loop feedback mechanism achieves accurate positioning without requiring additional flow rate monitoring hardware, thereby maintaining positioning accuracy while avoiding increased system complexity
Solution Approach 2:
The patent replaces direct flow rate monitoring (which would require additional mechanical/sensor components) with position-based feedback control using existing sensors. By substituting the measurement approach from flow rate monitoring to position monitoring, the system achieves the same compensation effect for viscosity variations without adding device complexity
2Device complexity
If preset valve assembly is used for typical conditions, then system simplicity is maintained, but positioning accuracy deteriorates under varying temperature conditions
Solution Approach 1:
The patent transforms the static preset valve assembly into a dynamic control system that continuously adapts its operation based on real-time position feedback. The valve timing and duration are dynamically adjusted according to the actual car position and speed, enabling accurate positioning across varying temperature conditions while maintaining system simplicity through software-based adaptation rather than hardware complexity
3Measurement precision
If valve timing is adjusted to compensate for viscosity changes, then positioning accuracy is improved, but control complexity increases
Solution Approach 1:
The patent adjusts control parameters (valve timing, pulse duration, frequency) based on feedback from position sensors rather than directly responding to viscosity changes. By changing operational parameters dynamically based on measurable position deviations, the system achieves accurate positioning while keeping control logic simple and based on readily available sensor data
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 solution enhances the accuracy and reliability of elevator car positioning and speed control, addressing various sources of inaccuracy without requiring modifications to existing systems, thereby improving performance and reducing operational complexity and costs.
Implementation Method 1
In the case of hydraulic elevators, controlling pressurized fluid (e.g., oil) achieves desired elevator car movement and position. The machine or drive controller operates a pump and valve assembly to control fluid flow and elevator car movement or position.
Implementation Method 2
At least one sensor provides an indication of a current status of the elevator car, the current status including at least a position of the elevator car or a speed of the elevator car
Data Source
AI summary
An illustrative example elevator system includes an elevator car and a valve assembly that selectively directs fluid flow to control movement of the elevator car. At least one sensor provides an indication of a current status of the elevator car, which includes at least a position of the elevator car or a speed of the elevator car. A processor receives the indication from the at least one sensor and adjusts operation of the valve assembly when the current status of the elevator car is different than a predetermined desired status.