Automated Storage and Retrieval Systems (often referred as AS/RS) is a customized combination of mainly three components - storage racks, storage/retrieval equipments & WMS. AS/RS system handles, stores and retrieve material as needed with precision, accuracy and speed under a defined degree of automation. Systems vary from relatively simple, manually controlled system operating in small storage structures to extremely large, computer-controlled storage/retrieval systems totally integrated with ERP system.

The primary advantages of AS/RS are:

• AS/RS systems are very dense system, they require small operating aisle, can go very tall, offer multi deep storage and thus minimize the floor space and enhance the storage density
• AS/RS is customized system offering high throughput. A single dedicated stacker crane can offer throughput as high as 45 pallets / hour.
• AS/RS offers extremely accurate inventory control as they are integrated with computer systems
• Being automated system AS/RS reduces labor involvement in operations and thus reduces the overall operation cost.
• AS/RS system are useful for harsh environment like cold storage & chemical storage application.

Following are the main safety features of AS/RS.

• AS/RS systems are typically automated man less system, they almost eliminates human interaction with moving equipment and increases the occupational health & safety levels in warehouses.
• All operational commands are given electronically from host system and through pre-programmed path & logic, eliminating all major risks associated with material & equipment damage.
• Catching devices & over speed governors are provided for hoisting movement to arrest over speed/acceleration of equipment, ensuring absolute trouble free operation.
• Limit switches & safety bumpers are provided at end of aisle to detect & avoid over-travel of equipments.
• Physical dimensions of load/pallet are checked in all three directions while entering of pallet on forks & over dimensional loads are rejected from the system, ensuring only suitable sized objects gets handled by AS/RS.
• Motion of load handling device (LHD) are locked during vertical & horizontal travel of equipment.
• Unlike fork trucks/battery stackers, AS/RS do not have telescopic mast. AS/RS mast is supported by bottom & top rail, restricting sway of mast during travel of equipment.

Below are some of the functional advantages of AS/RS over conventional storage systems

• While working on heights conventional forklifts and battery stackers offer increased resistance in capacity. On the other hand AS/RS offers the same working load at all the levels of storage system.
• AS/RS systems are self maneuvered, Equipment operator is not required throughout the movement of equipment.
• Being the electrical equipment, Stacker cranes draws power from bus bar running parallel to aisle. No Battery charging time or back-up batteries are required, hence AS/RS offers 24 hour availability.

The Warehouse Management System (WMS) is a customized software application for high level product management. WMS handles various tasks ranging from Data Management, Machine Control, Interface with ERP, Security Access & Maintenance, Queuing & Resource Management, Real time transaction processing & Reports Generation. Components of WMS are :-

• Inventory Control System
• Location Management System
• Handling Control System

All Bins/Pallets stored in ASRS system are given a unique tag (either bar code or RFID), while storing the item inside the AS/RS, The System first scans the tag on Bin or Pallet, based on information WMS allocates a storage location for that item. The tags are then mapped to their bin locations in the WMS, Electronic instructions are then transmitted to the handling equipment to store the item in allocated bin location. Similarly request for item retrieval are submitted through the WMS, which directs the equipment in the appropriate aisle to deliver the bin to delivery station.

Standalone AS/RS systems without interfacing with ERP can also be offered, In such case WMS also handles the inventory management modules besides the regular features of Location Management system & Handling Control system. In such case operational logic and Inventory transaction related reporting also gets controlled through standalone WMS. Moreover its also possible to choose man-on-board AS/RS system, where handling equipments are controlled through the operator cabin mounted on the equipments.

AS/RS can be expanded in linear directions i.e.- along the length & width of warehouse provided the available floor space permits expansion. However its not possible to expand the AS/RS in vertical direction, as both storage system and handling equipments are required to be replaced.