AMR Warehouse - The Distribution Center Revolution

We buy more and more off of the Internet, and we want our order as cheap as possible, and it must be delivered tomorrow, or even today. Solution?: Warehouse Mobile Robots to boost warehouse productivity.

    

In general,  Autonomous Mobile Robots are widely used in distribution centers  and fulfillment centres. We all have in mind those amazing videos with hundres of orange AMAZON Robots.

     

AMRs replace traditional ecommerce fulfilment tools targeted at increasing pickers efficiency and productivity. 

  

They are used for order picking operations, zone picking, goods-to-person, autonomous piece picking or flexible sortation.

     

The importance of mobile robots in achieving even a minimal level of warehouse automation is no longer a secret. Of course, amrs are not the only type of automated warehouse robots, there are many others like, palletizers, AS/RS, labelling, inventory robots, etc. 

       

This article will drive you through the different types or warehouse autonomous robots with special regard to their applications.

       

  

  

If you wish to know further about forked AGVs in warehouses instead, check this article: What can AGV do in a warehouse?

  

What can AMR Robots do in a Warehouse?

       

There are several types of warehouse amrs depending on their specific application.

  

     

 

          

AMRs for order picking process

      

Order picking is the process of retrieving the products listed in an order from their respective warehouse location based on customer requirements.

    

In the conventional method of order picking, SKUs stored shelves or racks are in a stationary pick area.

  

    

Free Infographic: Mobile Robots in e-commerce

Click here to download the infographic

   

Pickers will move from location to location to pick up SKUs and place them into open order containers on a conveyor or other carriers.

     

Once pickers have collected all of the items to deliver in an order, they take the order containers to the shipping area to finalize the delivery.

   

This method needs well-trained pickers, and pickers should work carefully to avoid mistakes. The most critical problem is that people will spend a lot of time moving in a huge warehouse to search and pick-up SKUs, which is a big waste of time and money.

   

In fact, collecting orders is the most important and most challenging for optimization, because it represents the largest waste of time.

        

???? Collecting order represents around 55% of the warehouse operating costs.

   

This first wave of mobile robots in DCs focused on reducing non-value-added tasks such “travelling” or “walking”, thus making human pickers more productive and focused on complex picking activities .

  

There is no doubt that eliminating travel time for order picking can increase productivity.

  

Basically, the first solution is to replace the workers’ feet with a robot.

  

With this model, AMRs focus on: 

 

• Minimizing the pickers’ collection time.

  

• Optimizing the picking route.

   

???? Check this article: Types of automated storage & retrieval systems

Types of autonomous mobile robots used in warehouses

      

Zone Picking AMRs

  

Free Infographic: Mobile Robots in e-commerce

In this case we have:

  

• SKUs are stored in shelving or racks in different zones. 

  

• Human pickers are allocated to different zones (for example, a warehouse aisle).

   

AMRs take an order container and move to the piking zones where operators deliver (“pick”) goods based on the robot’s needs.

  

 

   

Each operator contributes to filling orders on several robots, thus reducing operator walking time from one corridor to another.

 

If operators pick to all robots, its pick capacity is not limited by the capacity of a single robot. Traditional follow-bots are limited by the capacity of that single follow-bot.

  

This working strategy is mainly performed by PA-AMRs or Picking Assist Autonomous Mobile Robots.

  

There are many kinds of PA-AMRs, but basically, they are an AMR base with an operator interface that provides information about picking order.

  

The robot tells the operator “I want this item and here is where you can find it”. The user interface is also interactive, making it possible to provide further info about product or receive info from the operator such as “picking accomplished”.

  

Some other technologies can help the picker to identify SKUs faster by highlighting a section of the shelf.

  

• A light pointing to the target SKUs

  

• Paper pick lists

  

• Pick-to-light

  

• Etc

  

Once the picker completes the order, AMR will retrieve the container and take it to the next zone for picking the next part of the order.

  

When the entire order is finished, the AMR will move to a packing station, together with the fulfilled order container for final shipping.

 

This strategy sees many AMRs picking and moving among many zones, so distribution centers can complete enormous numbers of orders with high productivity.

    

 AMR in Goods-to-person (G2P)

     

The zone picking strategy results in substantial benefits. So, why not to improve this process further?

   

  

     

What is Good-to-person? G2P

 

  

     Free Infographic: Mobile Robots in e-commerce

 

It’s so simple that it’s embarrassing. Rather than having an operator walking along infinite corridors while looking for material in a warehouse (wasted time and energy), the material and goods come to the operator thanks to Goods To Person Robots.

  

The concept of “goods-to-people” can be easily explained as that the robots bring the target SKUs to the pickers to consolidate an order.

 

The obvious benefit is that there is no waste of time of people moving and searching the products ordered.

  

Despite the support of different technology, in zone picking, the pickers still need some time to search for the object in the rack.

   

Typical Characteristics of AMRs for shelves

    

     

How do Good-to-person AMRs work?

     

In this case, pickers remain at their workstations while software-driven AMRs deliver shelves with different materials directly to the order picker’s workstation.

    

The standby AMRs go into the warehouse and stops below the mobile shelf containing the ordered product.

     

Once arrived at the target shelf, the AMR will lift the entire shelf, move to the picking station with the shelf, join the queue waiting to be picked.

    

Directed by RF, pick-put to voice and/or pick-put to light technologies, pickers select the required material from the shelf and then “put” the selected items into a container or bin that has been assigned to an order.

   

Then, the AMR leaves the picking station and a new one in the waiting queue presents itself to fulfill another part of the order.

   

This assures that the goods are always waiting for people, and it doesn’t take people time to search for the goods.

  

The AMRs that finish their tasks return the shelf to its parking station or they continue with the same shelf to another picking station for a different order.

  

The greatest benefit of Goods-to-people is that it eliminates the time for workers walking and searching for goods in a distribution center.

   

Autonomous Mobile Picking Robots

     

We have replaced the feet, now it’s time to replace the hands.

   

  

AMRs can be used to pick SKUs into discrete orders when they’re configured with robotic picking tools such forks, conveyors, grippers, etc.

  

 

   

The robot acquires an order requiring an item, navigates autonomously to where the product is located and picks it.

   

Mobile picking robots have compartments or tote bins on them, and they put the products they pick into these areas.

  

   

These AMRs can use a vision system or other technologies to identify each item, then they can instruct their robotic arm to grab the target items for placement in the appropriate order containers.

   

After consolidating multiple picks from different locations in the warehouse, the AMR finishes a single order and goes to a delivery zone with the order fulfilled.

  

  

If you want to know more about these robots, do not miss our article dedicated to Autonomous Mobile Picking Robots. It explains into detail mobile piece picking characteristics and lists the most important suppliers. 

     

AMR in Flexible Sortation

  

Sortation is another efficiency problem in distribution centers.

  

AMRs can also play an important role in optimizing the sortation process.

  

Free Infographic: Mobile Robots in e-commerce 

  

According to the directives from the central management system, AMRs can sort items to multiple packing stations.

   

AMRs for sortation need to be equipped with a variety of handling technologies, from conveyor roller to tilt trays and cross belt systems, to deal with SKUs that have different weight, different shape, and in different containers.

  

How do Flexible Sortation AMRs work? check this video:

   

     

Workers place the parcels on sorting AMRs. Each parcel must be delivered to a given destination box.

   

When AMR detects that a destination box is full, it reports this information to the system.

  

The system will then notify other mobile robots to remove the full destination box and to transport it to the outbound area for delivery.

  

Once the sortation is done, an operator or an AMR will take the finished order away for shipment.

   

Another AMR will bring in an empty container to resume the sortation process.

   

AMR provides an attractive alternative to traditional fixed tilt-tray and cross-belt conveyor-based sortation systems that have historically been used within many busy warehouse and eCommerce distribution centers.

  

• This new method reduces the travel time that humans need to transport picks to specific, discrete packs.

   

• Initial deployment is less expensive and more flexible, being possible to fit into many types of warehouses or distribution centers.

  

• Compared to traditional sortation, the robots require less workspace to achieve the same parcel throughput.  

  

• The time needed to complete an installation is also prominently shorter than what is necessary when building conveyor-based sorting solutions.

   

 

         

Conclusions: What advantages represent AMRs for Warehouse DCs and fulfillment centres?

      

Three words: Picker productivity increases.

    

If we think about fulfillment centres, everything turns around picker productivity. AMRs can dramatically increase picks per hour, which means more capacity to complete orders with less staff. Some suppliers indicate that picking performance can be boosted by x2 or x3. 

      

???? Operator picking performance can be boosted by x2 or x3

    

So, a traditional operator with 70 picks per hour can easily meet 150 picks per hour aided by mobile robots.

      

Moreover, in order to accelerate mobile robots’ adoption, manufacturers of mobile picking robots are proposing these robots in a Robots as Service (RaaS) solution.

     

The main advantage of this strategy is that instead of paying the full price and taking the technological risks of robots, the user can pay as they need accordingly with agreed KPIs.

  

For example, customer can simply pay a monthly fee based on the number of picks the company might need the robots for.

  

This business model is very flexible and scalable for users as they can deploy robots according to their business scale.

  

What does increasing picking productivity mean?

   

   

• Reduced labour costs. Less staff. 

      

• Reduced extra time cost. Augmented fulfilment capacity during regular business hours reduces overtime hour costs. Basically, you’ll be able to deliver all required materials during traditional working hours without the need to pay for extra time.

       

• Indirect cost reduction. Less staff means less need for indirect costs. Facilities expend less in water, light, cleaning services, etc.

      

• Higher capacity to deliver orders helps meet service-level agreement (SLA) requirements and helps avoid penalties.

     

There are other benefits, for example:

     

• Reduced need of tools and hardware. Once mobile robots are deployed, companies avoid using traditional tools such RF guns or carts, which represents an investment savings and further reduced maintenance costs.

     

• Reduced order errors. Workers using Autonomous Robots are more accurate and commit less mistakes as compared with traditional manual picking.  Less mistakes implies reduced rate of consumer returns. So, this means reduced costs of reshipping correct items to customers.

 

• Capacity to afford variable fulfilment volumes that need capacity flexibility. Have you ever heard about “Christmas” or “Black Friday”? Companies dealing with ecommerce distribution centres must be able to adapt to those order picks. Often, they financially are obligated to large capital investments in systems such as conveyor systems that go unused for months. 

       

• And what happens when these companies have a seasonal order increase? They have to quickly hire more people. The problem is that it is not easy to recruit seasonal labor on a short timeframe, particularly if you don’t know exactly how many people you will need.

    

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