Picking Shuttle Coordination for Space-Efficient In-Aisle Retrieval
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Solution Overview
Problem
Existing shuttle-rack storage systems face inefficiencies due to the use of multi-axis gripping robots that require significant space, increase system cost, and limit the number of shuttles per rack level, necessitating shuttle elevators, which reduces picking performance and increases traffic density outside the rack storage block.
Innovation Solution
A method and system where shuttles on different rack levels cooperate to perform intra-aisle picking using biaxial gripping units that move vertically and horizontally, allowing products with low access frequency to be pre-picked within the rack aisle, reducing traffic density and enabling simultaneous picking at external stations without increasing overall installation height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multi-axis gripping robots are used for picking, then picking capability is provided, but space requirements increase and system cost increases
Solution Approach 1:
The picking function is segmented between two separate shuttles: one shuttle (first shuttle) transports the source container, while another shuttle (second shuttle) performs the gripping and product removal. This segmentation eliminates the need for a complex multi-axis robot on a single shuttle, reducing space requirements while maintaining picking capability.
Solution Approach 2:
The shuttles are designed with universal functionality to perform multiple operations: transporting containers, positioning containers for picking, and executing the actual picking action. This multi-functionality allows the system to achieve robot-like picking capability using standard shuttle components rather than requiring specialized robotic equipment.
2Ease of operation
If multi-axis gripping robots are used for picking, then picking capability is provided, but system cost increases
Solution Approach 1:
The system segments the picking function across multiple standard shuttles rather than using one expensive multi-axis robot. This approach uses simpler, more cost-effective components to achieve the same operational capability, reducing overall system cost.
Solution Approach 2:
The shuttles perform picking operations autonomously through coordinated movement and positioning. The system uses the shuttles' inherent transportation and positioning capabilities to execute picking without requiring additional expensive robotic systems, achieving self-service functionality.
3Device complexity
If fewer shuttles per rack level are used, then system cost decreases, but picking performance decreases and traffic density outside rack increases
Solution Approach 1:
The system enables continuous picking operations by allowing multiple shuttles to operate simultaneously on the same rack level. While one shuttle transports a source container, another shuttle can simultaneously perform picking, eliminating idle time and maintaining continuous productive action.
Solution Approach 2:
Source containers are pre-positioned on shuttles at the rack level before picking occurs. This preliminary positioning action allows the picking shuttle to immediately access the container without waiting for transportation, increasing picking speed and performance.
4Productivity
If shuttles are used for intra-aisle picking, then picking efficiency increases, but traffic density within rack aisle increases
Solution Approach 1:
The system utilizes the vertical dimension by operating shuttles at different rack levels simultaneously. This dimensional approach allows multiple picking operations to occur in parallel at different heights, increasing overall efficiency without proportionally increasing horizontal traffic density within the aisle.
Data Source
AI summary
It is disclosed a method for picking a product according to a picking order, which preferably belongs to a group of previously collected picking orders, by shuttles cooperating with each other in a shuttle rack storage system comprising a rack-storage block and a plurality of shuttles which are movable in a force-guided manner in a rack aisle defined between two rack rows on different rack levels, the method comprising the following steps: moving a first shuttle of the cooperating shuttles in a longitudinal direction of the rack-storage block along the rack aisle to a rack storage location in a first rack level, and subsequently (horizontally) retrieving a source container, which contains the product specified by the picking order, from the rack storage location onto the first shuttle; moving a second shuttle of the cooperating shuttles into and along the rack aisle at level of a higher second rack level (overlapping) over the previously lower-positioned first shuttle so that a gripping unit (fixedly) mounted on the second shuttle can remove the product from the source container positioned on the first shuttle; and delivering the product from the retrieved source container positioned on the first shuttle into a collecting container by: removing the product from the retrieved source container, which is positioned on the first shuttle, with the gripping unit of the second shuttle; and delivering the removed product to the collecting container positioned on one of the shuttles positioned lower than the second shuttle within the rack aisle (overlapping in the vertical direction), or positioned, lower than the second shuttle, at one end of the rack aisle.