How to Choose the Right Warehouse Automation Solution for eCommerce Order Fulfillment

Exploring different types of warehouse automation and warehouse robotics solutions

Warehouses need accurate, efficient fulfillment workflows to deliver exceptional customer service, remain competitive and run profitably. To achieve this, warehouses must overcome two industry-wide challenges: chronic labor shortages and high error rates.

Finding and retaining qualified labor has been the #1 challenge for warehouses since 2017 due to persistent labor shortages and annual employee turnover of 49%. In addition, over 60% of retailers identify manual processes and human errors as the number one root cause for inventory and fulfillment issues, with error rates averaging 1-3%.

To combat these issues, warehouses are increasingly introducing automation and warehouse robots into their eCommerce order fulfillment. Automated warehouses benefit from higher efficiency, improved picking accuracy, reduced labor needs and lower costs.

There is no one-size-fits-all solution when it comes to warehouse automation. Automation systems encompass everything from legacy conveyors to disruptive technologies like mobile robots and robotic picking, and each system has its own pros and cons.


The Evolution of Warehouse Automation

timeline of warehouse automation


warehouse conveyor

Considered the oldest and most traditional form of warehouse automation, conveyors consist of long winding strips of belts & rollers fixed in place and spread across a facility. Conveyors are used to sort and transport goods from one place to another. Conveyors are easy to operate and install and can handle a wide range of SKUs; however, in order to automate order fulfillment, they require integration with other piece-picking technologies, which adds complexity to the implementation process and operations. Conveyors are also highly rigid and cannot be easily moved or reconfigured if business needs change, putting them at risk of becoming fixed ‘monuments’ inside a warehouse. In addition, they also suffer from having a single point of failure, whereby one part of the conveyor breaking down can cause the entire system to stop.

Efficiency: 100-250 presentations per person/hour
Pros: easy to operate, handles wide range of SKUs, can be used for sorting
Cons: highly rigid, difficult to reconfigure or scale, expensive, single point of failure, large amount of spare parts needed to maintain


Shuttle System

warehouse shuttle system

In a shuttle system, fast-moving shuttles travel horizontally across storage racks, retrieve storage totes and deliver them to a lift, which then takes the totes down to a conveyor to be transported to a human or robotic picking station.

Shuttle systems are one of the most common and oldest forms of automated storage and retrieval systems (ASRS), having been on the market for approximately 20 years and accounting for ~70% of the ASRS market today. Shuttle systems require substantial vertical space in the warehouse, making them unsuitable for most smaller warehouses or mezzanine structures, but for the same reason offer good vertical space utilization, reaching heights of up to 60 feet. Shuttle systems can achieve high-throughput, however to do this they require advanced software that calibrates each tote’s sequencing on the lift module, which if managed incorrectly can act as a single point of failure.

The main drawback of shuttle systems is their cost, being one of the most expensive forms of automation. Additionally, shuttle systems have long implementation times (sometimes up to 3 years) and high maintenance costs. Similar to conveyors, shuttle systems are also highly rigid and inflexible and cannot be easily reconfigured once installed.

Warehouse automation companies providing shuttle systems include Dematic, Knapp, Vanderlande, TGW, Exotec, Schaefer and Daifuku.

Efficiency: 300-400 presentations per person/hour
Pros: well-known established solution, high-throughput, high vertical space utilization
Cons: expensive, long implementation times (1-3 years), inflexible and difficult to reconfigure, requires advanced software, single point of failure, difficult to maintain, expensive spare parts inventory, not suitable for most smaller warehouses (e.g. back-of-store) and MFCs

Cubic Storage

Cubic storage, also known as cube automated storage and retrieval (Cube ASRS), is a solution that consists of totes densely stacked on top of each other in a cube-like structure, on top of which mini-robots retrieve totes from inside the cube and deliver them to external human or robotic picking stations.

Cube-based storage is the densest form of warehouse storage available, however it can only reach a maximum height of 20 feet (three times lower than shuttle) and, similar to shuttle, is not suitable for mezzanine structures. Cube ASRS is simpler to implement and maintain than shuttle; it is also more modular and does not have a single point of failure, however it still relies on a fixed rigid structure that cannot be easily reconfigured, with strict design requirements such as perfectly-level floors. Installation times for cube ASRS are typically 6-18 months.

Cube ASRS systems are efficient only in 90/10 or 80/20 Pareto distributions (i.e. where 20% of SKUs account for most of the volumes), with throughput and cycle times negatively affected when robots need to often ‘dig’ several layers deep to retrieve a tote that is stacked below other totes. As such, cube ASRS is best-suited for warehouses whose main requirement is storage density.

Warehouse automation companies providing Cube ASRS include Autostore and Ocado.

Efficiency: 300-400 presentations per person/hour
Pros: high horizontal storage density, high throughput for high-runners
Cons: expensive, difficult to reconfigure and maintain, strict implementation requirements, long installation times, low efficiency (depending on volume distribution)

Autonomous Mobile Robots (AMRs)

mobile robots for eCommerce fulfillment automation were commercialized in the late 1990’s, and really took off after Amazon’s acquisition of Kiva Systems in 2012. Mobile robots ‘solved’ many of shuttle’s or cube’s problems, in that they were significantly cheaper, highly reconfigurable, and easy to implement, scale and maintain. This also enabled a novel sales model to emerge called Robots-as-a-Service (RaaS), which replaces the upfront expenditure of buying the system with a monthly subscription or lease fee per robot. RaaS significantly lowered customers’ upfront capital expenditure, thereby reducing business risk and adoption barriers to customers, and enabled new customers such as 3PLs to adopt automation at scale.

There are several types of AMR systems for warehouses and fulfillment centers:

Person-to-Goods (P2G) AMRs

person-to-goods AMR

In a P2G system (also known as ‘meet me’ or ‘follow me’ robots), AMRs meet human pickers inside the storage aisles, where humans pick SKUs directly from the storage shelves and place them onto the AMRs, which then move around the warehouse from one area to another, consolidating the order across several different human pickers. This significantly cuts down human pickers’ travel distances and increases their pick rates and accuracy; however, P2G systems are still quite labor intensive since they still rely on humans to do the picking and as such, do not achieve the picking rates of other AMR, shuttle or cube solutions. The main advantage of P2G AMRs is they are extremely easy to implement, requiring no reconfiguration to the warehouse since the picking process itself remains unchanged (because humans continue picking from shelves, as in manual operations).

Warehouse automation companies providing P2G AMRs include 6River Systems, Fetch Robotics, Locus Robotics and Rapyuta Robotics.

Efficiency: 100-200 picks per person/hour
Pros: flexible, easy to implement, safely operates around humans, low cost
Cons: highly reliant on human labor, low picking rates and density compared to other solutions


Goods-to-Person (G2P) AMRs

goods-to-person robot

In a G2P system, AMRs transport entire racks of merchandise to stationary human pickers, who pick SKUs directly from these racks. This has the benefit of significantly increasing pick rates and throughput and cutting cycle times compared to P2G systems. G2P systems are also highly flexible and adaptable, although they do require special shelving and separation from humans due to safety concerns. The racks can go up to 16 feet tall, thereby offering good vertical density. The main drawback of G2P AMRs is their continued reliance on human picking, with robotic picking very difficult to integrate due to the distinctive configuration of the racks.

Warehouse automation companies providing G2P AMRs include Geek+, GreyOrange, Hai Robotics, Quicktron and Addverb Technologies

Efficiency: 300-400 presentations per person/hour
Pros: increased pick rates & accuracy, flexible and adaptable
Cons: requires special shelving and separation from humans, reliant on human pickers

Goods-to-Robot (G2R) AMRs

Robotic Each Picking

In G2R systems, AMRs autonomously retrieve individual storage totes and deliver them to robotic picking stations. Such tote-moving systems combine the flexibility of P2G solutions, whereby they are able to operate with existing shelving and mezzanine structures, with the high throughput and low cycle times of G2P solutions. Because these AMRs only need to transport one tote at a time, G2R solutions can have much narrower aisles and thus offer higher storage density than G2P or P2G solutions, and even compared to cube when combined with multi-level mezzanine structures that permit higher vertical space usage.

Most importantly, G2R AMRs implement robotic picking alongside human picking, thereby almost entirely eliminating reliance on human labor and achieving a higher degree of automation than other AMR solutions. To achieve this, however, G2R solutions require advanced software that integrates robotic pickers with AMRs and orchestrates multiple workflows. Furthermore, to scale robotic picking as an automated fulfillment solution would require reliably picking a wide range of SKUs, which relies on advanced machine vision and AI technology. Recent advances in these technologies have enabled robotic pickers to generalize data and pick previously-unseen items with high accuracy, thereby enabling robotic picking for the majority of e-commerce and grocery SKUs.

The only provider of G2R AMR systems covering both AMRs and robotic picking in a single integrated solution is Brightpick.

Efficiency: 300-400 presentation per robot/hour
Pros: end-to-end fulfillment automation with robotic picking natively integrated into solution, eliminates labor challenges, flexible, increased pick rates, easy to implement, higher density compared to other AMR solutions
Cons: requires advanced software, G2P stations necessary if some SKUs are not robotically pickable

In the world of warehouse automation there are many choices. Each type of automation has its pros and cons depending on your needs. If you’re interested in learning how combining multiple types of automation can truly accelerate efficiency in your warehouse or fulfillment center, download our eBook: 1+1=3: How to unlock the efficiency your fulfillment center needs.

Want to learn more about Brightpick?

Brightpick fully automates fulfillment order picking for 3PLs, eCommerce and eGrocers, using state-of-the-art AMRs and robotic piece-picking to autonomously replenish, pick, and consolidate orders. Brightpick’s patented system is powered by advanced AI algorithms, industry-leading 3D vision and proprietary optimization & orchestration software. Contact us today to take your fulfillment to the next level.

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