Elevator Safety System Adaptive Braking Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing elevator installations with multiple cars in a common shaft face variations in braking travel due to varying coefficients of friction, leading to inefficient braking and potential collisions, especially at high speeds.
Innovation Solution
A safety system with measuring devices for detecting retardation and position, which calculates target retardation values for each elevator car's braking device, allowing for adaptive braking based on load state and operational conditions, and includes decentralized or centralized activation of braking devices to prevent collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a preset normal force is used in the braking device, then the braking device can be simplified in structure, but the braking travel varies significantly due to varying coefficients of friction and load states
Solution Approach 1:
The braking force regulating device dynamically adjusts the normal force applied by the braking device based on real-time feedback from measuring devices that detect actual retardation and operational conditions. This transforms the static preset normal force into a dynamic, adaptive parameter that maintains consistent braking performance across varying friction coefficients and load states.
Solution Approach 2:
The system incorporates measuring devices that continuously monitor the actual retardation achieved during braking and feed this information back to the braking force regulating device. This feedback loop enables the system to automatically adjust the braking force to achieve target retardation values, eliminating variations in braking travel caused by friction coefficient changes and load variations.
2Reliability
If high minimum spacing values are used to prevent collision at high speeds, then collision prevention is improved, but the braking travel becomes very long
Solution Approach 1:
The system dynamically determines the minimum spacing value based on real-time operational parameters including speed, load state, and measured retardation. Rather than using a fixed high minimum spacing, the system adjusts the spacing requirement adaptively, allowing shorter braking distances when conditions permit while maintaining sufficient safety margins when risks are detected.
Solution Approach 2:
The system changes the braking parameters (normal force, retardation target, minimum spacing) based on varying operational conditions such as speed, load, and friction coefficient. By optimizing these parameters in real-time, the system achieves both short braking travels and reliable collision prevention without relying on conservative fixed values.
3Loss of time
If high levels of retardation are applied to stop elevator cars quickly, then stopping time is reduced, but unnecessary high deceleration can cause falling over and injury of persons
Solution Approach 1:
The system adjusts the retardation parameter dynamically based on the elevator car's operational state, load conditions, and detected risks. The braking force regulating device modulates the deceleration rate to achieve optimal stopping performance while maintaining safety, preventing excessively high retardation that could cause injury to persons inside the car.
Solution Approach 2:
The measuring devices provide continuous feedback on retardation levels and operational conditions to the braking force regulating device. This feedback enables real-time adjustment of braking intensity, ensuring that deceleration remains within safe limits while still achieving timely stops, thereby preventing injury to passengers.
4Reliability
If the braking force is optimized for the least favorable case, then collision prevention is ensured, but variations in braking travel arise and operation is inefficient
Solution Approach 1:
The braking system transitions from a static conservative approach to a dynamic adaptive approach. The braking force regulating device continuously adjusts braking parameters based on real-time measurements of friction coefficient, load state, and operational conditions, optimizing braking performance for each specific situation rather than relying on worst-case assumptions.
Solution Approach 2:
The system changes braking parameters (normal force, retardation target, spacing requirements) adaptively based on actual operational conditions. This enables the system to achieve optimal braking performance and operational efficiency for each specific scenario while maintaining safety through continuous monitoring and adjustment, eliminating the need to over-design for least favorable cases.
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 optimizes braking by reducing variations in stopping distance, preventing unnecessary high deceleration that could cause injuries, and ensuring reliable collision avoidance by tailoring braking forces to instantaneous operational states.
Implementation Method 1
the preset normal force generates, due to varying coefficients of friction, varying braking forces
Data Source
AI summary
An elevator installation includes a first elevator car and a second elevator car, each having a respective braking device, and a safety system that monitors the elevator cars. The safety system has for each braking device a braking force regulating device for regulating a braking force of the respective braking device. The safety system activates at least one of the braking devices by the associated braking force regulating device in order to prevent collision of the first elevator car with the second elevator car.