This past fall, the US unemployment rate fell to near-historic lows of 3.5%. While that’s great news for the economy and for workers, it’s bad news for organizations who find themselves paying higher wages to attract qualified workers. All across the country, retail and order fulfillment operations are struggling to contain rising labor costs triggered by this contracting labor pool.

Compounding the issue is the availability of labor. Organizations find themselves constantly recruiting and training, only to have employees move on to another, higher-paid opportunity. Around the country, there are numerous facilities designed for three shift operations but have never been able to staff them completely.

Many warehouses and distribution centers find themselves combatting labor scarcity and costs by making the switch towards automation within their facilities. One emerging technology in particular — autonomous mobile robots, or AMRs — has the potential to dramatically reduce your dependence on your area’s labor pool.

Key Benefits of AMRs

Autonomous mobile robots can provide many benefits in today’s distribution centers. Some of the most important include:
  • Increased flexibility: AMRs provide dramatic levels of flexibility in comparison to traditional material handling equipment. Whatever application being accomplished today can be easily modified tomorrow. Scalability can often be accomplished in a few hours, and it’s a fairly simple task to relocate AMR systems to different zones, buildings, or states within a day or two.
  • Increased accuracy: Because AMRs and robots can automatically scan verify that the correct product has been picked, the correct destination container, and the correct location, the end result is often a much higher order accuracy rate within your operation, which provides a much higher level of customer satisfaction.
  • Higher throughputs: Because AMRs rely on both a robotic control system (RCS) and either your WES or WMS, they can automatically generate the shortest routes to each destination. This increased efficiency will enable an operation to be more productive in many of its processes and workflows.
  • Lower risk of single point of failure: Because AMRs typically work in fleets, there is a layer of redundancy that is not typically available with other solutions like conveyors, sorters, and AS/RS system. If an element of traditional material handling systems goes down, the entire system is down. This cascades, making the entire zone and facility come to a standstill. If an AMR goes down, the system can deploy a different AMR automatically and throughput is never affected. This allows the operations to continue seamlessly.
  • AMRs reduce labor costs and staff: It is not uncommon for operations embracing AMRs and human operation to see a 30% reduction in labor costs — and that is the low end. AMRs and robotic systems can realize up to 100% reductions. The level of automation and return on investment often dictate the final decision.

9 AMR Applications to Reduce Your Labor Requirements

1. High-Speed Parcel or Order Sortation and Consolidation — Manual Induction

In this scenario, an AMR is used to sort parcels, products, or orders, removing the need for miles of expensive cross belt and tilt tray conveyor. Product is manually inducted onto the top of the AMR bot. The scanner above reads the barcode and immediately sends the bot to its destination chute. The bot then moves parallel to its order position and tilts its contents down the chute. Once all the parcels or items are collected down a chute, another AMR will come and take the bag or gaylord to shipping, and the process is repeated.

2. Robotic Induction High-Speed Parcel or Order Sortation and Consolidation

This process works virtually the same as described above, except parcels or products are inducted onto the AMR via robotic arms. Likewise, induction can use robotics, conveyors, and other, automated technology to complete the entire process labor-free.

3 & 4. Order Picking — Goods-to-Person

Method A: AMRs eliminate all the walk and search time often associated with order picking. Operators are in their shelving/rack zones. Open orders are staged on the bottom shelf levels. Operators using radio frequency (RF) are directed which items to pick from the SKUs in their zone or aisle. They scan the location and then the item picked to verify the correct SKU. Then scan the tote’s identification barcode to verify the destination. Once all the items have been placed in the order, the AMR automatically comes to retrieve it and brings it to its next zone or to shipping. Another AMR automatically brings the next tote/order. This method allows the AMRs and humans to work independently with no wait and dwell time.

Method B: In this instance, shelving with optimized shelf levels and dividers hold the inventory. These shelves are stored on the warehouse floor. AMR pick and place bots move down aisles and under the sections of shelving until they select the exact SKUs required. They gently lift the shelving and rotate towards the shortest path to the desired pick station. The bots queue in line and present the shelving to the operator-run pick station. Pick-to-light is used to identify the active shelf, cell, and quantity to pick. The operator picks the items and puts them in the active order tote beside them. When the last item has been picked from that section of shelving, the AMR automatically takes the shelving section back to the buffer storage area and the next shelf moves into position automatically. This methodology eliminates operator wait and dwell time.

These methods improve not only throughput by reducing worker travel time and allowing the worker to pick more orders in a shorter amount of time, but can also lead to up to a 20% decrease in space required for storage because it enables high-density storage solutions.

5. Replenishing Robotic Picking - Goods-to-Person

To reduce more labor for the above methods, cases or totes of inventory are delivered to a robotic pick arm, which then places the inventory on one of the shelves described above. An AMR pick and place bot delivers the section of shelving to the robotic arm. Once the last tote or case has been loaded on the shelving, the AMR delivers it to buffer storage or pick station. This process is constantly repeated to replenish the order picking activities.

6. AMR Automated Storage & Retrieval System (AS/RS)

This AMR can move vertically within a rack structure as well as on the floor as a traditional AMR. This dual capability allows it to become an automated storage & retrieval system (AS/RS) with remote picking stations. This AS/RS system maximizes vertical cube to create a high-density storage system with the ability to create as many picking stations as throughput and labor requires.

When product is required for an order, an AMR moves on the floor into the storage rack system to retrieve the product. When it reaches the correct floor location, it engages the rack, and the bot will then rapidly move vertically. When it reaches the correct SKU, it uses its inserter/extractor device to retrieve the tote and then move down the rack to the floor.

When the AMR reaches the ground, it will then shuttle the product to its designated pick station. An operator will make the pick and place the SKU into the open order. The AMR then automatically delivers the SKU to the next pick station requiring the item or stores it back into the rack system.

7. Order Picking — Person-to-Goods

In this scenario, an AMR might travel to a zone or aisle where a worker is waiting (or where a worker will meet). At that time, the worker will locate the required inventory and pick the required number of units, often enabled by a pick-to-light system. Once the required items have been picked, the bot will then automatically find the next worker in the next required aisle or zone.

In some cases, particularly in smaller operations, a single worker might accompany the AMR the entire time, picking items as they go.

8. Replenishment — Shelving & Flow Rack

AMRs can also be used for automating the replenishment process within your operation, freeing up laborers to perform higher-value tasks aside from simply moving inventory.

There are several ways that AMRs can be used for this application, but a simple one is using an AMR that can utilize its fork or gripper system to retrieve and store up to five cases or totes on its internal shelves. It then moves via the shortest path to the shelving or rack position and places it in the correct position. This process is constantly repeated and eliminates human labor in the replenishment process. The AMR can induct its inventory and discharge empty totes from conveyor, vertical lift modules (VLMs), AS/RS systems, shelving, etc.

9. Replenishment — Retail Store

For retail stores that feature extensive on-site storage, AMRs can be used to retrieve items from storage in order to replenish the main floor. This is often achieved by a bot picking items and then depositing them in a cart or cage, which is then picked up by a worker for final restocking. The same process can also happen in reverse, allowing an AMR to return and stow inventory back to storage as necessary, or to break down deliveries upon receipt.

Charting Your Path Forward

Whatever your unique challenges or goals, it’s important to understand that you have many options at your disposal when it comes to leveraging AMRs within your operation to reduce labor costs and realize other benefits. The list of scenarios outlined above is by no means exhaustive — the possibilities are nearly endless.

Likewise, applications can be validated by simulation and then creating a scaled version of the system for a proof of concept (POC). This methodology allows organizations to implement a smaller version of their system to not only validate but flush out process and technical questions. Doing POCs using AMRs are far more viable than traditional material handling systems, and the material used in a POC is easily integrated into the full system, eliminating waste

Ed Romaine is VP of Marketing & Business Development, Conveyco ( He has over 30 years in helping organizations improve their order fulfillment and warehouse systems and processes including order picking, software, and conveyance technologies. He is also the former chairman of the Automated Storage & Retrieval Systems (AS/RS) group, the Supply Chain Execution Group (SCE), and Order Fulfillment Solutions Group (OFS) of America. Ed can be reached at or 215.512.2613.

This article originally appeared in the November/December, 2019 issue of PARCEL.