Elevator Switching Device for Brake Control Failure
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Solution Overview
Problem
Conventional elevator apparatuses fail to control the motor power supply relay or brake power supply relay when the brake control device fails, leading to potential user entrapment during an emergency stop.
Innovation Solution
An elevator apparatus with a relay system that includes a driver, operation control device, brake control device, and switching device, which allows independent control of the motor power supply relay even if the brake control device fails, ensuring the car can be moved to an evacuation floor and preventing user entrapment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the brake control device is used to control the motor power supply relay in normal operation, then the elevator can be controlled efficiently, but the system reliability decreases when the brake control device fails
Solution Approach 1:
A switching device is introduced as an intermediary between the brake control device and the driver. This switching device receives control signals from both the brake control device and the operation control device, and selectively switches between them based on failure detection. When the brake control device fails, the switching device automatically switches to receive signals from the operation control device, ensuring continuous control capability without requiring direct complex interconnections between all components.
Solution Approach 2:
The control system is segmented into independent control paths: one through the brake control device for normal operation, and another through the operation control device for emergency backup. The switching device enables selective activation of these segments, allowing the system to maintain functionality by activating the backup segment when the primary segment fails, thereby improving reliability without permanently increasing system complexity.
2Ease of operation
If the brake control device fails, then the car cannot be moved to the evacuation floor, but adding a switching device increases device complexity
Solution Approach 1:
The switching device serves as a mediator that automatically manages the transition between normal and emergency control modes. It receives inputs from both the brake control device and the operation control device, monitors their status, and automatically switches to the operational source without requiring manual intervention or complex control logic distribution across multiple components.
Solution Approach 2:
The switching device incorporates automatic failure detection and self-switching capability. It monitors the control signals from the brake control device and automatically switches to the operation control device when a failure is detected, without requiring external control or manual intervention. This self-service mechanism simplifies the overall system by eliminating the need for additional complex control logic to manage the failover process.
3Speed
If the brake control device is used for emergency stop control, then the response time is fast, but the system becomes vulnerable to single point of failure
Solution Approach 1:
The control system transitions from a static single-source control architecture to a dynamic multi-source architecture. The switching device enables the system to dynamically switch between the brake control device and the operation control device based on real-time operational status. This dynamic adaptability allows the system to maintain fast emergency response capabilities while eliminating the single point of failure vulnerability by having multiple active control sources.
Solution Approach 2:
The system changes its operational parameters by switching between different control signal sources based on failure detection. When the brake control device is functional, the system operates in normal mode using its control signals. When failure is detected, the system changes parameters by switching to receive control signals from the operation control device, thereby maintaining reliability without sacrificing the fast response capability of the original emergency stop system.
Data Source
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AI summary
There is provided an elevator apparatus that can control a motor power supply relay or the like even if a brake control device fails. To this end, the elevator apparatus includes: a relay having a function of blocking supply of electric power to a motor or a brake of an elevator; a driver that drives the relay; an operation control device that outputs a control signal to the driver; a brake control device that outputs a control signal according to a control signal output from the operation control device in normal time, and outputs a control signal independent of the control signal output from the operation control device in an emergency stop of the elevator; and a switching device that receives as an input the control signal output from the operation control device and the control signal output from the brake control device, and that switches the control signal to be output to the driver from the control signal output from the brake control device to the control signal output from the operation control device when the brake control device fails.