OHT Vehicle Buffer Start Control for Congested Track Flow

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The frequent stopping and starting of OHT vehicles due to proximity distances in congestion or bottleneck sections lead to vibrations and shocks, reducing the lifespan of the system and increasing the risk of operation errors.

Innovation Solution

Implementing a buffer distance or buffer waiting time when a following OHT vehicle starts after a preceding vehicle moves out of range, thereby minimizing the repetition of start and stop cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the following vehicle stops immediately when reaching the proximity threshold distance to the preceding vehicle, then collision prevention is ensured, but frequent stopping and starting occurs causing vibrations and shocks

Engineering Contradiction:

Improvecollision preventionVSAvoidvibrations and shocks

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system performs preliminary action by detecting when the preceding vehicle is decelerating or stopped and proactively controlling the following vehicle to stop before reaching the proximity threshold distance. This prevents the following vehicle from needing to make abrupt stops when the threshold is reached, thereby reducing frequent vibrations and shocks while still ensuring collision prevention.

Inventive Principle:

Principle #10Preliminary action

2Speed

If the following vehicle starts immediately when the separation distance exceeds the proximity threshold distance, then system responsiveness is improved, but repetition of start and stop events increases

Engineering Contradiction:

Improvesystem responsivenessVSAvoidrepetition of start and stop events

Core Design Contradiction:

SpeedVSProductivity

Solution Approach 1:

The system applies preliminary action by detecting when the preceding vehicle is accelerating and proactively starting the following vehicle before the separation distance exceeds the proximity threshold distance. This allows the following vehicle to start in advance, reducing the frequency of repeated start-stop cycles while maintaining responsive system operation.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the proximity threshold distance is reduced to increase track capacity, then vehicle density increases, but collision risk increases

Engineering Contradiction:

Improvetrack capacityVSAvoidcollision risk

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system uses feedback by continuously monitoring the acceleration state of the preceding vehicle through inter-vehicle communication. Based on this feedback, the following vehicle dynamically adjusts its stopping distance - maintaining a larger safe distance when the preceding vehicle is decelerating or stopped, and allowing closer proximity when the preceding vehicle is accelerating. This enables increased track capacity while maintaining collision safety through adaptive distance control.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12280961B2Method and device for controlling overhead hoist transfer vehicle

Publication Date: 2025.04.22 SYSTEM ENGINEERING MEGA SOLUTION CO LTD

AI summary

A method and a device for controlling an OHT vehicle are proposed. The method and device presents a solution in which it is possible to minimize a repetition of start and stop of a vehicle, due to congestion on a track, by providing a buffer distance or a buffer waiting time, when the control target vehicle starts due to moving out of range of a proximity distance to a preceding vehicle, after stopping according to reaching of the proximity distance to the preceding vehicle, during driving the OHT control target vehicle.