Warehouse execution systems (WES): Blending human-centered workflows with automation

As warehouses become more automated, warehouse execution system (WES) software, which focuses on enabling multiple automated systems and related manual processes to work in concert to fill orders, is becoming more important.

Consider this factoid: More than a quarter (26%) of warehouses are expected to be automated by 2027, up from 14% a decade earlier and 18% at the close of 2021, according to a 2023 projection from analyst firm Interact Analysis.

The automation trend is altering the software stack needed to run today’s DCs. For certain, warehouse management system (WMS) solutions remain relevant for most DCs, but WES is seen as being at the center of what it takes to coordinate work in automated DCs, especially those with multiple systems.

The end game, say WES providers, is to orchestrate both people-centered workflows and automated zones as one to ensure orders get picked, packed and shipped on time. And even though the WES market is fragmented with vendors coming at it with different strengths, a consensus is forming that the value of WES is in “orchestrating” all available resources around order fulfillment.

“If you look at what has been happening in materials handling, we’re seeing an eruption of automation and robotics technologies hitting the marketplace,” says Art Eldred, vice president and growth officer with Vargo, a WES provider. “The problem that can happen is that if you are deploying automation with one process in mind, its use can end up being suboptimal because it wasn’t integrated into an orchestrated fulfillment workflow.”

WES has been around for several years, going back at least to the last decade when vendors began using the term. WES sits between the WMS layer that manages warehouse transactions and manual workflows and the traditional warehouse control system (WCS) that controls and monitors automated systems.

WES sits in the middle of this stack, at times overlapping with WMS functions like order release, but like a WCS, having real-time insight into the status of automated systems. Not all WES are alike, but generally, they provide functionality such as load balancing and automation-aware order release.

“I think we all agree we’re moving toward increasingly heterogeneous environments for automation,” says Dan Gilmore, chief marketing officer with Roboteon, which offers a robotics fulfillment platform with WES capabilities. “Not every company is there yet in terms of using multiple systems, but more are thinking they’ll be using multiple solutions, and those solutions will need to talk to each other, most importantly, to optimize the flow though the facility, which is where the orchestration concept comes in. I think it’s fair to say that WES is about maximizing that flow. There are capabilities needed underneath that, but in general, you should be talking to vendors who understand the flow of a distribution center and have tools and capabilities in their software to maximize total throughput.”

Breaking down orchestration

So, what does orchestration mean when talking warehouse fulfillment and not violins? At its core, it’s about assessing order requirements and assigning tasks to different resources to optimize overall throughput.

A WES will typically get orders from a WMS or enterprise resource planning (ERP) system, and then deal the work out to different resources with an eye toward avoiding bottlenecks. With Vargo’s WES, the software is constantly looking at the incoming order pool and getting feedback from automated systems to figure out the best way to release work and level-load resources to speed up fulfillment, says Eldred.

“[WES] is all about feedback loops and being and able to synchronize and sequence work,” says Eldred. “It comes back to the ability of the software to be able dissect each and every workflow, and then determine when can I start orchestrating more work to the resources I have.”

Importantly, adds Eldred, WES software does this orchestration rapidly as it releases work to different subsystems or to WMS-directed manual processes. The WES doesn’t always dictate to an automated or robotic system exactly what to do within its own zone, though it looks at the load on each zone and figures out how much work to meter out to each subsystem.

“You want to give each system enough work so that it’s well utilized, and it can optimize its processes or its fleet, but not get them too far ahead so that it starts to suboptimize the throughput of the entire building,” says Eldred.

To achieve this end, says Eldred, Vargo continues to enhance its sequencing logic. This entails some understanding of how different systems work. For example, one type of system may need to be orchestrated by clock/time measures, whereas another type of system may need the WES to understand the cycle counts or cadence of its output.

“An effective WES needs to be able to throttle the amount of work given to different systems, based on the parameters those systems use,” Eldred.

Another focus for Vargo, Eldred adds, is to make its WES self-adjusting to external events or unforeseen constraints. For instance, if a supplier shipment is late and doesn’t show up in time to replenish a forward picking system, the WES will adjust.

“We’ve really worked on this auto correcting behavior of our WES, so the software can go ahead and intelligently make the optimal decision on how to adjust to unforeseen events, taking the analysis off the plate of supervisors and into the digital world,” Eldred says.

When it comes to judging WES, look for advanced functionality around orchestration and simulation, says Gilmore. “Make sure there is some real substance to the solution,” he says.

Areas that Roboteon has focused on with its platform include its orchestration engine, including AI-based task assignment to eliminate wasted time and handoffs between systems, as well warehouse workflow simulation. The simulation in the platform can be used for longer term plans such as number of autonomous mobile robots (AMR) needed for a peak season, or to estimate picking costs under multiple robot parameters, though it also works during order release to orchestrate across current resources to optimize overall flow, Gilmore explains.

“Simulation allows the system to consider all the different possibilities across thousands of configurations and conditions and say, ‘OK, when the conditions look like this, this is the best way for the work to be released for this block of time,’” Gilmore says.

Vendors also need expertise in integrating with different systems and monitoring the current status and capacity of systems, Gilmore adds.

“WES vendors need integration expertise between the WES and whatever is on the other side, whether that’s traditional automation or robotic goods-to-person systems, or mobile robot systems,” he says. “You’ve got to have a platform that enables you to integrate with those things very easily and rapidly, and that is reusable.”

The main aim of WES, Gilmore adds, is to avoid bottlenecks to enable a smooth flow of work. For example, you don’t want a robotic palletizing cell waiting on cases delivered from an AMR system, but you don’t want so many AMR missions that work piles up in front the palletizing cell, which might lead to staging delays or congestion.

“One of the things that WES can do is to alleviate those bottlenecks and improve the flow by smartly understanding what work is there and what work is coming and being able to meter that work in a way that maximizes the total throughput of the system, not each individual piece,” Gilmore says.

Going forward, Gilmore says, more companies will want an orchestration platform that is hardware agnostic and reuseable, meaning it can integrate with robotic or automation systems from different vendors, with perhaps one DC or region using one brand of AMRs, but a different brand of AMRs in another site or region.

“You want a high level of flexibility to add new vendors or new types of equipment more easily and plug it into a framework that allows you to have interoperability across robot fleets,” Gilmore says.

Lighter automation

Vendors are addressing WES from different directions. Leading systems integrators have had WCS software for decades and have built up WES platforms from that basis. Additionally, most major WMS vendors have added WES capabilities.

Historically, most users of WES bring it in to manage a major new automation system being deployed, but that trend might be shifting. Some WMS providers with WES capability point out that WES components can be layered over a WMS to manage and optimize lighter automation like mobile robots.

Joe Kozenski, product director for WES at Blue Yonder, which offers all types of supply chain execution software including its widely used WMS, says that in the last few years, Blue Yonder has added WES capabilities consistent with WMS data to permit users to quickly onboard automation like AMR fleets in a way that unites automated workflows and tasks with ones carried out directly in WMS. These WES services include a Tasking Engine to understand and direct tasks, and a Robotics Hub for orchestration of processes like assistive picking from aisles with AMRs.

“From our WES perspective, we’re taking a warehouse management-first approach to integrating and onboarding automation and implementing it into workflows,” Kozenski says. “We’re actually seeing a lot of our customers want to dabble in automation and accelerate it with their existing processes.”

Blue Yonder’s WES capabilities allow for a cohesive approach to tasking, regardless of whether a task is done directly in the WMS by an associate using an RF device, or on a tablet that is attached to an assistive picking AMR, Kozenski adds, which helps with orchestration and integrated data insights.

“Now when you look into your WMS, you see the same history and transactions, whether a human resource facilitated the pick, or a robotic entity helped facilitate the pick.”

The Tasking Engine that is part of Blue Yonder’s WES services, Kozenski adds, is effective because it understands task completion times regardless of the agent involved.

“We want to understand task completion time for any entity or human resource doing the work, whether it’s an AMR moving things around, or tasks within an automated storage and retrieval system, or temporary workers using WMS, or full-time, highly experienced associates using the WMS,” he says. “The key for us is to understand resources and tasks across the board—human or machine—to find out what expected duration or delivery times are.”

The user perspective

Major third-party logistics (3PLs) companies with warehousing services have been layering in more automation, using different types of mobile robots, as well as solutions like cube storage and picking systems, as well as traditional automation. This has made some major 3PLs familiar with WES software and orchestration needs.

Rob Wright, vice president of automation and engineering with DHL Supply Chain, says multiple WES solutions are used successfully within DHL. There isn’t one single WES or orchestration solution used everywhere, he adds, but the software does help with orchestration.

The most prized WES functions are around load balancing of automated systems with each other, as well as coordination with more manual processes like picking certain items from aisles to complete orders, says Wright.

“We do use [WES solutions], particularly when we need to balance more than one automation area,” Wright says. “We may have one robotic system that is picking slow movers, for instance, but then we’ll have fast movers or large items in separate areas that need to go with order lines out the robotic system. The question is: How do you get those different systems to work together? To meet that need, we’ll employ a warehouse execution system at those sites to help us do that. We don’t have a standard one we use everywhere. The most common thing we’ll do is we’ll go to a single automation integrator and use their software to tie things together.”

WES software packages have improved over the last several years, says Wright. They are not only useful for load balancing and order consolidation, but also for how their order release logic can work high priority orders in the mix of work being released to systems, with an eye to hitting service levels for high priority orders.

“WES helps us with order prioritization,” says Wright. “When you’ve got a priority order, you’ve got a service level you have to meet, and so the software can make sure those orders get to the top of list, so to speak, when it needs to. We use WES for that as well.”

To simplify the integration of robotics and automation with WMS, DHL Supply Chain has also begun using software from SVT Robotics, Wright says. While not a WES solution, the platform helps with rolling out automation more rapidly. “We use them as an integration layer, which helps us make the connection really quick, and that actually helps us move faster [on deployments],” Wright says.

Think optimized processes

Ultimately, WES is more than middleware—its objectives are to improve operations by solving challenges like order consolidation between systems and eliminating bottlenecks to compress cycle time, while governing workflows that span manual and automated systems. That makes it more than a traditional WCS, say vendors.

A WES solution should be able to coordinate automated workflows with manual picking processes as part of order consolidation, says Jonathan Puckett, senior director of solution architecture with Swisslog, which has more than 500 deployments of its SynQ software worldwide. While not formally touted as a WES, SynQ integrates WMS functionality, orchestrates material flow and provides automation control functionality.

WES functions like load balancing and order release, as well as task interleaving, work to accelerate processes and synchronize them around operational objectives. In practice, this means a WES can do things like manage picking and replenishment for a robotic cube storage system, but also coordinate related tasks like order consolidation of oversized items kept in static storage that don’t fit into an automated system, but need to be married up with items coming out of an automated zone.

“Ultimately, [WES] involves task interleaving,” says Puckett. “We are managing the loads—the entry and arrival times between different systems and materials handling equipment, to determine the best way to fulfill orders. That is orchestration in a nutshell.”

A WMS will also track order completions and factors like inventory levels and costs, adds Puckett, but WES software is a more real-time solution that load-levels and coordinates processes as orders are released to the floor to be executed.

“With a WMS or enterprise resource planning systems, the insights are more after the fact, whereas with WES, it’s about what can the operation do right now to fill orders in the most efficient way,” he says. “In logistics, you don’t get time back. Once you lose seconds in the coordination of processes, that time is gone.”