OHT Interlock Control for Safe Rail Inspection Zones
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Solution Overview
Problem
The existing OHT management systems face safety risks due to the potential for accidental activation of interlocks, which can lead to safety accidents when operators inspect facilities without properly setting interlock information.
Innovation Solution
An OHT management system that includes a work terminal generating work progress information during inspections, which communicates with an OCS to automatically set interlocks on the OHT, preventing it from entering sections where the operator is positioned, using repeaters, sensors, and a maintenance lift to ensure accurate and automatic interlock activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual interlock setting is used during inspection, then operator control flexibility is maintained, but safety risks increase due to potential human error in activating interlocks
Solution Approach 1:
The system automatically detects the work terminal's position and autonomously activates the interlock for that section, eliminating the need for manual interlock setting by the operator. The system serves itself by monitoring its own state and taking appropriate safety actions without human intervention.
Solution Approach 2:
The OCS continuously receives work progress information from the work terminal and uses this feedback to determine when and where to activate interlocks. The system monitors the terminal's position and automatically responds by setting the appropriate interlock, creating a closed-loop safety mechanism.
2Reliability
If automatic interlock setting is implemented, then safety is improved by eliminating human error, but system complexity increases due to additional sensors and communication requirements
Solution Approach 1:
The work terminal serves multiple functions: it is both the inspection device and the trigger for interlock activation. The OCS performs dual roles as both the control system and the safety management system, reducing the need for separate dedicated safety devices.
Solution Approach 2:
The work progress information acts as an intermediary signal that bridges the work terminal and the interlock system. This information carrier enables automatic interlock setting without requiring direct complex communication protocols or additional intermediary devices.
3Reliability
If interlock is always activated during inspection, then safety is ensured, but productivity decreases due to OHT movement restrictions
Solution Approach 1:
The interlock is activated only for the specific rail section where the work terminal is positioned, rather than system-wide. This localized approach ensures safety at the work location while allowing OHT operations to continue uninterrupted in other sections of the system.
Solution Approach 2:
The interlock state dynamically changes based on the work terminal's position and inspection status. The system transitions between locked and unlocked states automatically, allowing flexible OHT movement when no inspection is occurring while maintaining safety during inspection activities.
Data Source
AI summary
Embodiments of the inventive concept provide an OHT management system and a control method for the OHT management system for automatically setting an interlock in an operation section at which an operator is positioned, while the operator inspects an OHT or an article facility, even in a case in which the operator does not set an interlock information at the operation section. The OHT management system includes a rail; an OHT driving autonomously on the rail; a work terminal which generates a work progress information during a work procedure for proceeding with an inspection by closely approaching the rail within a predetermined distance; and an OCS for turning on an interlock information so the OHT does not drive at a section at which the work terminal is positioned, if the OCS communicates with the OHT to set the interlock information of the OHT and is input with the work progress information by communicating with the work terminal.