ASRS Vehicle Proximity Queuing for Blocked Target Cells
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Solution Overview
Problem
In automated storage and retrieval systems, congestion occurs around frequently visited cells like ports due to the uncertainty of container handling vehicle positions, leading to delays and inefficient bandwidth usage as vehicles wait for position updates from the central control system.
Innovation Solution
Implementing a proximity sensor system on container handling vehicles to detect when another vehicle is beyond a predetermined distance, allowing the central control unit to command the first vehicle to move into a target cell without waiting for position confirmation, thereby reducing queuing times and optimizing bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the central control system waits for position confirmation from container handling vehicles before allowing movement, then collision safety is ensured, but queuing delays increase and bandwidth efficiency decreases
Solution Approach 1:
The system performs preliminary safety checks using proximity sensors before movement is initiated. The proximity sensor on the first vehicle detects whether another vehicle is within a predetermined distance ahead, and only if the path is clear does the control unit command movement. This preliminary detection eliminates the need for continuous position confirmation during movement, reducing queuing delays while maintaining safety.
Solution Approach 2:
The patent replaces the traditional centralized position-reporting system with a decentralized sensor-based detection system. Instead of relying on vehicles to continuously report their positions to the central control system, proximity sensors on each vehicle actively detect the presence of other vehicles within a predetermined distance, substituting mechanical/communication-based position tracking with optical/electromagnetic sensor detection.
2Loss of information
If container handling vehicles wait for position updates from the central control system, then accurate position tracking is maintained, but bandwidth usage increases and traffic efficiency decreases
Solution Approach 1:
Each container handling vehicle is equipped with a proximity sensor system that autonomously detects the presence and distance of other vehicles without requiring continuous communication with the central control system. The vehicle's control unit processes this sensor data locally to determine whether to proceed with movement, enabling self-service position awareness and eliminating the need for constant centralized position updates.
Solution Approach 2:
The system implements a feedback mechanism where proximity sensors continuously monitor the environment and provide real-time distance information to the vehicle's control unit. This feedback loop allows the vehicle to automatically adjust its movement decisions based on detected proximity to other vehicles, maintaining accurate situational awareness without excessive bandwidth consumption.
Data Source
AI summary
A method of operating an automated storage and retrieval system includes: a rail system including a first set of parallel rails arranged in a horizontal plane and extending in a first direction, and a second set of parallel rails arranged in the horizontal plane and extending in a second direction which is orthogonal to the first direction, which first and second sets of rails form a grid pattern in the horizontal plane including a plurality of adjacent grid cells, a central control unit configured to receive, transmit and process data signals of a plurality of container handling vehicles for handling storage containers of the automated storage and retrieval system. Each container handling vehicle includes a vehicle body, a wheel assembly provided on the vehicle body, the wheel assembly being configured to move the vehicle along the rail system in both of the first direction and the second direction, a vehicle control unit configured to receive data signals from, transmit data signals to and process data signals of the central control unit, and a proximity sensor system configured to detect another container handling vehicle of said plurality of container handling vehicles and determine whether or not it is within a predetermined distance. The method includes detecting with the central control unit that access of a first container handling vehicle to a target cell, which is one of the plurality of grid cells, is blocked by a second container handling vehicle, transmitting a data signal from the central control unit to the vehicle control unit of the first container handling vehicle commanding the first container handling vehicle to move into the target cell when the second container handling vehicle is beyond said predetermined distance.