Warehouses are of enormous importance to supply chains, providing service and economic benefits to businesses and customers. In Part 1 of this series, we discussed how the drive towards higher supply chain efficiency has motivated companies to adopt robotic technologies to perform fulfilment tasks in their warehouses. We have also seen how the emergence of recent technologies (AI, computer vision, etc.) has enabled robotic systems to integrate and dynamically adapt to changing warehouse environments, both autonomously and collaboratively.
Following on, let us now examine and discuss use cases in which robots are leveraged to support loading and unloading, order picking, and sortation.
Loading and Unloading
For many supply chain managers, anticipating the arrival of goods is a major challenge, and of course, any delays in the freight unloading process will simultaneously ripple through the entire delivery schedule, causing further disruptions to the subsequent drop-off schedules.
While on the dispatch side, practitioners are often expected to respond to schedule disruptions. Add to that the realities of everyday warehouse issues such as labour availability, inconsistent work rates, absenteeism, and so on, and it is easy to see how these challenges are further aggravated.
One effective way to ease these difficulties is to introduce autonomous case-handling robots that can be readily deployed in trucks and containers. For example, the highly manoeuvrable compact robot, StretchTM (Boston Dynamics), can easily travel in and out of containers to load and unload cartons. This device is untethered and features a small footprint and a flexible arm with adaptive grippers to grasp many carton types1 up to 20 kg. Its advanced vision system also enables fast and precise carton detection, and since the controls are embedded, these robots don’t require any pre-programming of package types and can be quickly commissioned.
By its very nature, order picking is a repetitive, time-consuming, and often non-ergonomic task. However, when automated, picking systems can run uninterrupted and without human intervention, while the advanced grip system2 ensures stability and safety in material handling, resulting in more streamlined order processing.
Businesses involved in preparing high order volumes should, in particular, consider automating picking, either with robots or with automated conveyor systems3. In addition to error prevention, robotic solutions also boost order pick rates on account of their agility and material-handling safety abilities. The following are examples of the different types of robotic picking solutions available.
Anthopomorphic 4 Arms
can handle individual items (eaches) or cartons and basically perform pick-and-place tasks. They are essentially designed to remove products from one location and place them in another. Although simple, these tasks are extremely repetitive and time-consuming, so following deployment, pick operators can now be reallocated to other value-added work that is both more challenging and professionally satisfying.
These articulated arms are usually equipped with advanced vision systems to identify items and a tactile gripping element for product handling. The robots deliver high performance and flexibility to businesses fulfilling large volumes of daily orders; several examples are:
- The sustainable tableware business, Nupik Internacional, introduced order picking robots to its Barcelona distribution centre. There, a MecaluxTM anthropomorphic robot can prepare three orders simultaneously and is capable of handling up to one thousand boxes per hour.
- The 3PL, Havi Logistics, is outfitted with an anthropomorphic robot in its Portugal logistics centre and picks orders made up of higher-turnover items. Operating at high speed, the robotic arm is installed in the freezer store and prepares 40% of the orders.
- The deep-frozen food company, Cabezuelo Foods (Spain), is equipped with an anthropomorphic robot that performs 150 movements and autonomously handles 1,350 boxes per hour
Autonomous Mobile Robots (AMRs)
are basically vehicles capable of manoeuvring along prescribed routes and are typically used to transport products to pick stations. They are fitted with sensors and software containing a digital layout of the facility, allowing them to interpret their surroundings. These robots serve two purposes: operators can use them as picking carts, placing the goods retrieved on top of the robot (Person-to-Goods); alternatively, the robots can bring products to the operators preparing orders at workstations (Goods-to-Person)
In addition to picking robots, companies looking to increase order pick rates can introduce other automated solutions to the warehouse, for example:
Automated Storage and Retrieval System (AS / RS)
consists of a variety of frameworks for automatically unloading and recovering loads from specific areas in a facility. These systems are particularly useful in situations where there is fast movement of high item quantities or where efficient space utilisation is a requirement in a facility. These robots move horizontally and vertically within the storage aisles, and while they store goods, they also increase the material flow rate by working non-stop and supplying pick stations with products more rapidly.
- The France-based tool manufacturer, SAM Outillage, commissioned an AS / RS for handling boxes prepared by a goods-to-person method. Prior to installation, order pickers walked up to eleven kilometres a day in the warehouse to locate products, and in contrast, the majority of walk and search time is now eliminated as MecaluxTM stacker cranes and conveyors move the goods to the operators.
- Zeek Logistics is a US-based eCommerce company fulfilling around 28,000 types of goods and dispatches around 2,000 orders daily. In the past, order picking was paper-based and generated significant walking distances and search times for the order pickers (this also led to high pick error rates). These issues were resolved by the introduction of a flexible and scalable automated solution, the AutoStore®.
This vertical storage system utilises a grid for efficient storage and retrieval, and newly arrived stock is placed into bins that are then inserted in the grid4. The system incorporates 22 robots that glide over the grid, identifying and retrieving the bins containing the required items via long grippers and delivering them to a workstation for operators to pick. When that task is completed, the robots return the bins back to the grid.
- The Switzerland-based 3PL, MS Direct, sought an automated warehouse solution to maximize throughput rates and flexibility and in the end, selected AutoStore® as their system of choice. The high storage density ratio5 offered by the system also maximised workspace utilisation in the new Lake Constance facility. This system comprises 30,000 storage bins (with capacity to double) and has 48 battery-powered robots moving along the grid rails to retrieve, arrange, or deliver bins via a conveyor system to any one of nine workstations for picking and replenishment.
Once orders are picked and labelled, they are then placed onto a conveyor, ready to be loaded into a trailer for shipping. The robots work efficiently around the clock, making sure that reserved bins are strategically placed in the top layers of the grid. This permits operators to retrieve bins immediately at the start of their shift (thereby avoiding idle times), ultimately ensuring high material flow rates are constantly maintained.
Sortation robots detect, characterise, and sort objects into the correct bin locations. The sortation process is tailored to specific business needs and adapted to the type of items being sorted. In recent years, these robots have become more prominent due to the speed and accuracy benefits they offer over conventional sortation methods. They typically handle parcels and can sort vast volumes of packages accurately, ensuring timely delivery to the final destination. Several types are available, each with its own unique features and capabilities:
- X-Y Gantry Robots
comprise a horizontal bridge that uses linear motors to move along orthogonal axes. Generally used where a large workspace is needed, the end-effector is usually a tilt tray, which can drop packages to 60 predetermined destinations at a rate of 600 per hour.
- Articulated Arm
can also sort parcels at a rate of 600 packages per hour at 60 locations. In this case, a pre-sort process is generally required.
- Mobile Robots
usually consist of a tilt tray mounted on top of a mobile robot. Using various sensors, the robot detects the attributes of each item (size, weight, shape, colour, or barcode) and determines the appropriate destination for each item based on the sortation criteria. The robot then moves along the designated area and puts the parcel in the appropriate bin. Mobile robots can be further classified as:
- Elevated Mobile Robots
These operate on an elevated platform, allowing them to move above and around obstacles in the warehouse
- Mezzanine Mobile Robots
These are especially useful for eCommerce fulfilment centres that require high-speed sortation of high order volumes. Utilising a mezzanine platform, these robots can move both horizontally and vertically within the warehouse and are highly space efficient.
- Direct Sorting Mobile Robots
Known to be highly flexible, these generally employ sortation algorithms based on the item’s characteristics. The robot scans the item, compares it to the rules, and determines where it should be placed.
In the next and final installment, we will discuss the applications of warehouse robotics to palletizing / depalletizing, packing, transportation, and inventory control.
- Irrespective of shape, weight and size ↩︎
- Also known as an End-Effector, a peripheral device that attaches to a robot’s wrist, allowing the robot to interact with its task ↩︎
- Despite the ongoing justification to automate processes, we can assume that traditional order picking will remain an inevitable part of warehouse operations, given the rising trend of e-commerce and individualization with high-mix and low-volume warehouses ↩︎
- The grid can contain up to 28,400 bins, each with a carrying capacity of 30 kg ↩︎
- Up to four times higher than that of traditional storage systems ↩︎
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