Elevator Drive Control for Passenger Oscillation Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Elevators in low-to-midrise buildings can experience emergency stops due to passenger-induced vertical oscillations, which interfere with service availability and require mechanical intervention to reset the overspeed governor.
Innovation Solution
The elevator system includes drive electronics that monitor electrical current and sensor data to detect abnormal passenger behavior, adjusting the elevator car speed to prevent oscillations from exceeding the natural frequency or triggering the governor, thereby avoiding emergency stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the governor is configured to stop the elevator car when speed exceeds a preselected threshold, then safety is improved, but service availability deteriorates due to unnecessary emergency stops triggered by passenger-induced oscillations
Solution Approach 1:
The drive electronics continuously monitor machine operation information (electrical current, sensor data) to detect abnormal passenger behavior patterns. When oscillations are detected, the system provides feedback by automatically adjusting the elevator car speed to prevent governor activation, thereby maintaining service availability while preserving safety through intelligent monitoring and adaptive control
Solution Approach 2:
The drive electronics dynamically change the operating parameters of the elevator system by adjusting the elevator car speed in response to detected abnormal passenger behavior. This parameter adjustment prevents the speed from exceeding the governor's preselected threshold during oscillation events, avoiding unnecessary emergency stops while maintaining safe operation
2Productivity
If the drive electronics adjust the elevator car speed to prevent governor activation, then service availability is improved, but device complexity increases due to additional monitoring and control functions
Solution Approach 1:
The drive electronics are designed to perform multiple functions: normal speed control, abnormal passenger behavior detection through electrical current and sensor monitoring, and automatic speed adjustment to prevent governor activation. By consolidating these functions into the existing drive electronics rather than adding separate systems, the patent minimizes device complexity while achieving improved service availability
Solution Approach 2:
The drive electronics autonomously detect abnormal passenger behavior and self-adjust the elevator car speed without requiring external intervention or complex additional systems. The system uses its own operational data (electrical current, sensor outputs) to identify oscillations and automatically modifies speed parameters, enabling the system to serve itself and maintain operation without mechanical intervention
Data Source
AI summary
An illustrative example elevator system includes an elevator car, a machine that selectively causes movement of the elevator car, and a drive that controls the machine to control movement of the elevator car at an intended elevator car speed. The drive is configured to use information regarding operation of the machine to determine whether an abnormal passenger behavior (APB) condition exists that affects movement of the elevator car. The drive is configured to alter the elevator car speed when the APB condition exists.