Elevator Safety Controller Velocity Profile Emergency Stop
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Solution Overview
Problem
Traditional elevator safety systems are error-sensitive, leading to immediate stops that can leave users stranded between floors, causing inconvenience and potential safety risks.
Innovation Solution
An elevator safety controller that receives status information from various elevator components and selectively causes either an immediate stop or a velocity profile stop, allowing the elevator car to move to the next possible landing floor in emergency situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional safety systems cause immediate stop upon detecting operational anomaly, then safety risk is addressed, but users are left stranded between floors causing inconvenience
Solution Approach 1:
The safety controller dynamically adjusts the stopping strategy based on the type of failure detected. For non-critical failures, it implements a velocity profile stop that allows the elevator to reach the nearest floor. For critical failures, it executes an immediate stop. This dynamic response resolves the contradiction by making the system adaptable to different failure scenarios.
Solution Approach 2:
The controller changes the stopping parameters based on failure classification. Instead of always using the same immediate stop parameter, it modifies the velocity profile and stopping distance parameters according to the failure type, enabling differentiated response that balances safety and user convenience.
2Speed
If immediate stop is caused via elevator brake operation, then emergency stopping is achieved, but elevator car may stop between landing floors
Solution Approach 1:
The emergency stopping function is segmented into two distinct modes: immediate stop for critical failures and velocity profile stop for non-critical failures. This segmentation allows the system to choose the appropriate stopping method based on the failure type, preventing unnecessary stops between floors while maintaining safety for critical issues.
Solution Approach 2:
The velocity profile stop acts as an intermediary solution between immediate stop and normal operation. For non-critical failures, it provides a controlled deceleration that allows the elevator to reach the nearest floor, serving as a mediator that balances emergency response with safe landing requirements.
3Ease of operation
If velocity profile stop is used to reach nearest landing floor, then user entrapment is prevented, but stopping time is extended
Solution Approach 1:
The velocity profile stop implements a controlled deceleration that is more gradual than immediate stop but still prioritizes reaching the nearest floor. It applies partial braking action sufficient to safely reach the next floor without requiring a complete immediate stop, thus reducing stopping time while preventing user entrapment.
4Reliability
If single-channel failure causes immediate stop, then safety is maintained, but system complexity increases with redundant channels
Solution Approach 1:
The control system dynamically evaluates the failure type and determines the appropriate response. Instead of always stopping for any failure, it dynamically assesses whether the failure is critical or non-critical and adjusts the stopping strategy accordingly, reducing unnecessary stops while maintaining safety.
Solution Approach 2:
The system changes the response parameters based on failure classification. For single-channel failures in redundant structures, it modifies the stopping parameter from immediate stop to velocity profile stop, allowing the elevator to continue to the nearest floor while maintaining safety monitoring.
Data Source
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AI summary
An elevator safety controller (10) arranged for receiving status information from a plurality of elevator components of an elevator system (200) is disclosed. The elevator safety controller (10) being configured: to cause an immediate stop for an elevator car (20) via operation of an elevator brake of the elevator system (200), if the received status information fulfills a first emergency stopping criteria; and to cause a velocity profile stop for an elevator car (20) via operation of a motor drive unit (104) of the elevator system (200), if the received status information fulfills a second emergency stopping criteria.