Automated Picking Solutions for Limited Warehouse Space

As warehouse real estate becomes more expensive and harder to expand, businesses are under pressure to make better use of the space they already have. According to CBRE, annual rents for industrial and logistics facilities in the U.S. more than doubled between 2013 and 2023, reaching $8.43 per square foot. Global warehousing costs, including rent, taxes, and service charges, increased by 3.6% in the 12 months from March 2024. This comes due to a rise in demand as the e-commerce industry booms, combined with a lack of supply in major cities across the world.

Unfortunately, there is little businesses can do to stop warehouse rent rises, but there are other measures that can be taken to look after the bottom line. If space comes at more than a premium, then companies must make better use of the space they already have.

This is especially true for urban warehouses, smaller operations, or legacy facilities that can’t easily expand.

Automated picking systems and warehouse robotics can completely transform operations, but not all systems are equally space efficient. This guide explains all major types while highlighting the best for small or crowded warehouses.

What Are Automated Picking Systems?

Automated picking systems are technologies, or system of technologies, designed to reduce or eliminate manual inventory retrieval in warehouses and distribution centers. These systems may include robotic arms, mobile robots (AMRs), pick-to-light tools, vision systems, automated storage and retrieval systems (ASRS), and more. The goal is to improve efficiency, accuracy, throughput, and maximize space.

Benefits of Automated Picking Systems (and The Impact on Space)

Automated picking systems offer a wide range of operational benefits, including faster order fulfillment, improved accuracy, reduced labor costs, and better inventory control. But in facilities where space is at a premium, these systems also directly enhance how efficiently your warehouse footprint is used.

• Faster throughput with less floor space: Automation increases pick speed and order accuracy, allowing you to move more inventory through a smaller physical area.
• Fewer aisleways, more storage density: Good-to-person solutions eliminate the need for workers to walk through the warehouse, enabling narrower aisles and denser layouts.
• Smarter inventory slotting: Built-in logic dynamically optimizes where items are stored, improving access while eliminating wasted or underused space.
• Vertical storage optimization: Systems like vertical lift modules (VLMs) and cube-based ASRS reclaim overhead space often unused in traditional layouts.
• Ultra-dense storage configurations: Cube-based systems, like AutoStore, store bins in tightly packed grids, reducing required footprint by up to 75%. Optimize bin storage even further with built-in cartonization for bin layouts.

• Consolidated work zones: With automation handling movement and retrieval, pick stations can be centralized, shrinking operational sprawl and freeing up valuable floor space.

• Scalable capacity within existing walls: Many systems expand modularly, adding robots, bins, or workstations, so you can grow output without needing more square footage.

• Consistent 24/7 performance: Automated systems maintain high efficiency regardless of labor availability, reducing the need to plan around shift changes or staffing.

Types of Automated Picking Systems

Automated picking systems typically follow one of three fulfillment strategies:

• Goods-to-Person (GTP): Items are automatically delivered to a stationary picker, often through a system like ASRS, shuttles, or cube-based robotics.
• Goods-to-Robot: Instead of delivering items to a human operator, goods are brought to a robotic picking cell, where robotic arms handle the actual item selection.
• Person-to-Goods (PTG): Human pickers travel to storage locations to retrieve items, with automation providing guidance through tools like pick-to-light or voice-directed systems.

Some solutions are more space-efficient than others. GTP systems are especially beneficial for space-constrained warehouses because they eliminate the need for wide aisles and enable dense, vertical storage layouts. The following technologies can be deployed in fulfillment operations to create an automated picking system. We'll discuss them in relation to the strategy they support:

Goods to Person

As the name suggests, technologies supporting a Goods-to-Person strategy deliver goods directly to a human picker at a workstation. The picker interacts with the inventory (e.g., selects items from totes or bins), and the system returns the storage container afterward. They are ideal for space-constrained warehouses because they eliminate the need for wide aisles and enable compact, high-density layouts.

• Automated Storage & Retrieval Systems (ASRS): An umbrella term for systems that automatically store and retrieve goods, reducing manual handling and increasing storage density. Learn more about ASRS.

• Cube-Based Systems (i.e. AutoStore): Stack inventory bins in a dense grid, with robots accessing bins from the top of the grid and delivering them to human operators or robotic picking arms at the workstation. See how AutoStore cube storage works.

• Shuttles: High-speed carts that move totes along racking levels. Ideal for high-throughput, structured storage environments. Compare AutoStore and shuttle systems.

• Vertical Lift Module (VLM): An enclosed automated system with trays stored vertically on both sides of a central extractor, which retrieves and delivers the required trays to an ergonomic picking opening.

• Vertical Carousel Module (VCM): A vertical loop of carriers that rotate continuously to bring stored items to a fixed, ergonomically positioned access point at the operator's request.

• Vertical Buffer Module (VBM): A tote-handling system that stores totes in an enclosed vertical shelving structure and uses a central mast to retrieve and deliver them to a picking station or conveyor.

• Mobile Robotics (AMRs/AGVs): Transport goods to pick stations autonomously. They typically work by moving underneath a portable inventory shelf, lifting them, and carrying them to a workstation.

Not all technologies in this category are used the same way. For example, shuttle systems can be part of a GTP workflow when delivering goods directly to a picker, but in other setups, they may simply route inventory to conveyors for automated palletization, without human interaction. The key distinction for GTP is whether the system delivers items directly to a person for picking.

Goods to Robot (or Connected System)

• Robotic Picking Cells: Robotic arms that pick individual items, automating piece-picking tasks at the workstation. These are typically paired with a cube-based system, VLM, or one of the other types of ASRS systems. AutoStore, the top-performing cube-based system in the market, features CarouselAI which is a robotic picking solution that picks eaches out of the bin at the workstation.

• Connected System: Many times, an automated picking system will be comprised of an ASRS that delivers to a connected conveyor. The inventory totes or bins can be automatically placed on the conveyor for further processing downstream.

Person to Goods

A person-to-goods fulfillment strategy is the traditional picking strategy that we all know of - operators walk multiple miles per day among tall racking systems to retrieve orders for inventory fulfillment. With the help of automated solutions, operations are making their person-to-goods processes more efficient. While less space-optimized than GTP, PTG tools can be cost-effective for targeted zones or hybrid fulfillment setups.

• Mobile Robotics (AMRs/AGVs): Robots follow and assist pickers, reducing cart-pushing and walking effort but still requiring person-led inventory retrieval.

• Guided Picking Systems: These systems optimize manual picking tasks but don't eliminate the need for human travel through the warehouse, so they don't provide space-saving benefits like goods-to-person solutions.

  • Pick-to-Light: Uses lights at storage locations to guide pickers to the correct items and quantities.
  • Voice-Directed Picking: Workers wear headsets and receive spoken instructions, freeing their hands and improving accuracy in complex pick environments.
  • Vision Picking: Uses smart glasses or AR to visually direct workers to picks. Useful in highly variable or SKU-dense environments.

Top 3 Picking Solutions to Optimize Space

Many automated picking technologies are well suited for compact footprints, but here's my top three picks:

1. Cube-based systems like AutoStore excel in buildings with ceiling heights under 40 ft, where dense horizontal storage and minimal aisle space deliver the greatest value. If you're considering a robotic cube storage system, here's AutoStore vs Competitors: A Comparative Analysis of Robotic ASRS

2. Vertical systems such as VLMs and vertical carousels are ideal for facilities with taller ceilings with a very small footprint, allowing you to reclaim overhead space that would otherwise go unused. Considering a vertical solution? Here's Vertical Lift Modules vs Vertical Carousel Modules: Which Technology is Right for You?

3. Case shuttle systems tend to be more beneficial in high-bay warehouses (over 40 ft), where tall racking structures can maximize vertical storage potential. Need a deeper dive on cube storage and shuttle systems? Here's AutoStore vs Shuttle Systems: A Comparative Analysis

While space is a critical consideration, it’s just one of many factors that impact warehouse performance.

To optimize your operation holistically, you need to look beyond storage density. Explore how to improve warehouse efficiency across the board or read on for key implementation considerations when evaluating automated picking technologies and partners.

Implementation Considerations

• Space constraints: Consider ceiling height and floor space. For example, vertical systems like VLMs require tall ceilings, while AMRs/AGVs are better for low-clearance or flexible layouts.
• Order volume & variety: Choose a system that aligns with your order profiles - how many lines per hour does the system need to support?
• Inventory characteristics: Match the system to the size and weight of your goods. Heavy items require unit-load cranes whereas small parts are ideal for cube storage.
• Cost, ROI & total cost of ownership: Factor in upfront costs, maintenance, expected savings, and ROI timeline to evaluate long-term value.
• Throughput requirements: High-throughput operations may justify the investment in a goods-to-person automated system; slower operations may benefit from more economical, person-to-goods solutions.
• System integration: Choose systems that can connect with your existing IT and WMS infrastructure to avoid costly reconfigurations.
• Maintenance & support: Consider the level of ongoing service and technical assistance.
• Scalability: Opt for systems that can grow with your operation, whether by expanding grid size, adding robots, or increasing workstations.
• Employee training & usability: Evaluate the learning curve and how the system will enhance worker productivity and ease of use.
• Safety & ergonomics: Automation reduces physical strain and injury risk, improving workplace safety and potentially boosting employee retention.
• Implementation timeline: Some systems deploy in weeks, others take months. Assess how quickly you need to go live to minimize disruption.
• Environmental impact: Consider energy usage, emissions, and material handling efficiency—especially if sustainability is a business priority.
• Vendor or integration partner: Look for partners who understand your needs, offer clear ROI projections, and provide long-term support.

Choosing the Right Space-Saving System

When space is at a premium, automation is no longer a luxury...it’s a necessity. Whether you're outfitting a tight urban warehouse or rethinking an aging facility, automated picking systems offer flexible, scalable ways to increase capacity and throughput.

From cube-based storage like AutoStore to high-throughput shuttles and vertical systems like VLMs, there’s no one-size-fits-all solution. The best choice depends on your facility layout, inventory profile, and growth goals.

Need help evaluating which system fits your space? Talk to a Kardex expert or explore more in our warehouse space optimization guide.