Robotic Order Picking Systems: What You Need to Know

Warehouse order fulfillment involves many repetitive tasks. The most important and foundational one is order picking. It’s usually one of the biggest expenses in a distribution center, often making up more than half of operational costs.

That’s why it’s critical to understand the different robotic picking systems and assess which can improve the operational efficiency of your distribution center. The right fulfillment technology can realize significant gains in productivity, minimize idle time, lower costs, and speed up order delivery times. Quick and accurate robotic solutions and innovative picking algorithms can lead to optimal operational efficiency, happy consumers and higher loyalty and retention rates.

First, What Is Order Picking?

Order picking is the process of selecting items from warehouse inventory to fulfill orders placed by customers, often through e-commerce purchases. It is the basis of warehouse workflows and the most labor-intensive and expensive order fulfillment tasks. Traditionally, it is done manually by people walking through long warehouse aisles to retrieve ordered items and bring them back to the packing station to ship out to consumers.

Consumers are now expecting faster delivery times with multi-SKU orders shipped directly to their homes. Given the impact of order-picking on costs, operational efficiency, and accuracy, businesses are looking toward new robotic technologies and processes to improve productivity. Robotic picking algorithms increase pick time, while minimizing idle time to ensure SLA commitments are always met.

So What Are Robotic Picking Systems?

In the simplest of terms, a robotic picking system is an order fulfillment system that uses robots and warehouse execution system software to automate all or part of the picking process in an e-commerce warehouse.

These robotic systems work alongside your warehouse staff. They take on the dull, repetitive tasks that can lead to burnout, freeing up your people so they can focus on more meaningful work.

Types of Robotic Picking Systems

There is a wide variety of robotic systems that fulfillment and distribution centers can choose today to automate order-picking. While all systems improve operational efficiency and speed up pick time, the increase in productivity varies depending on the type of order-picking method the technology supports. In general, robotic picking systems fall under these three categories:

1. Person-to-Goods (PTG) Automation

As the name suggests, Person-to-Goods order-picking technology involves people going out into the aisles of a warehouse or retail facility to pick items. Various forms of automation can help make the PTG process less tiring, time-consuming, and more efficient. A popular automation solution is a smart cart-type AMR robot. The warehouse associate meets up with the robot at the pick site, removes the items from the inventory rack, puts them into the robot, and then each goes their separate way to another pick location. People walk less because they stay in a zone – often an aisle or two.

warehouse worker picking through inventory

Person-to-goods warehouse picking

2. Goods-to-Person (GTP) Automation

The Goods-To-Person picking system involves robotic systems that bring the goods to the order picker. The picker is stationary or at least is not walking through the aisles of the warehouse. GTP automation results in higher order-picking productivity than PTG, because it minimizes walking. Examples of Goods-To-Person automation include AS/RS and Autonomous Mobile Robots (AMR) solutions, such as Racks-to-Person or Totes-to-Person picking robots. We discuss these types of robotic systems in more detail later in the article.

AMR Retrieving Warehouse Goods

Goods-to-Person Automation – inVia Picker Robots

3. Goods-to-Robot (GTR) Automation

This involves a more complex robotic manipulation, where one robotic system brings the inventory from the shelves to a robot that picks the items for the order. This solution uses pick-and-place robots in place of human pickers.

Types of Order-Picking Robots

The term “warehouse automation” brings to mind images of large, vertical industrial robots such as carousels and conveyors, but there is a variety of picking robots that can be deployed in the eCommerce distribution centers. Many of the newer robotic picking systems are designed to work within your existing infrastructure, so you can avoid costly construction projects or warehouse redesigns. In general, the picking robots fall under the following categories:

1. Automated Storage and Retrieval Systems (AS/RS)

AS/RS are large, fixed systems that use robotic cranes or conveyors to move products to and from storage. These Goods-to-Person (GTP) robotic order-picking systems deliver high productivity rates, reduce the amount of foot traffic for warehouse workers, and provide high storage density. However, they are expensive and require considerable investment in infrastructure.

2. Autonomous Mobile Robots (AMRs)

AMRs are smaller, more scalable and flexible. They navigate the warehouse autonomously using onboard sensors to detect obstacles and automatically navigate around them. There is a wide range of mobile robotic picking systems on the market today:

– Cobot/Smart Cart AMRs are collaborative self-driving carts that travel to the aisle and shelf where the inventory container is located. They are met by an associate, who takes the item off the shelf and places it into the mobile robot, scanning it to verify the right item was chosen. This solution is based on Person-to-Goods (PTG) fulfillment method.

– Racks-to-Person AMRs are low-profile robots that go underneath an entire shelf of goods, lift up the shelving unit and carry it to an order-picking station. While an improvement from the order-picking cobots, this Goods-to-Person automation solution does not eliminate the dependencies between people and robots, which may result in bottlenecks. It’s important to keep in mind that in addition to the potential bottlenecks, implementing racks-to-person AMRs can also be associated with high infrastructure costs, as it may require modifications to the existing shelving units and other warehouse infrastructure.

– Totes-to-Person AMRs further refine Goods-to-Person automation by enabling mobile robots to remove inventory containers from the storage shelves containing items to be picked. The robot then travels independently, bringing the tote from the warehouse shelves to an associate.

inVia Robotics uses a patented “Totes-to-Person” approach, where inVia Picker robots navigate the warehouse and autonomously remove inventory containers from the racks and deliver them to the inVia PickerWall, a dynamic high-density pick/put wall that inVia’s AMR robots build with each day’s orders. The system decouples dependencies between people and robots, allowing people to work in bursts, while robots operate tirelessly 24/7. This highly efficient system delivers 5x+ increase in picking productivity.

Warehouse Order Picking Robot

inVia PickerWall, a Totes-to-Person system, that decouples dependencies between people and robots.

3. Pick and Place Robots

Pick and place robots are used in eCommerce fulfillment distribution centers to automate the process of picking individual items from storage locations and placing them into shipping cartons or totes. These robots are typically equipped with a robotic arm and a gripper or suction cup to pick up and manipulate items with precision and accuracy.


There is a wide selection of robotic picking systems that can help you realize significant gains in productivity, minimize idle time, lower costs, and increase customer satisfaction. Systems that minimize warehouse walking and decouple the dependencies between people and robots can have the biggest impact on a fulfillment operation.

Goods-to-Person automation offers more favorable results in the areas that matter most to 3PLs warehouse operators and online retailers: speeding orders, sharply boosting pick rates, reducing idle time, and increasing productivity. Choose a mobile robotic system to minimize CapEx and costly infrastructure changes.

Curious to Learn More?

It’s easy to get overwhelmed by acronyms and new fulfillment technologies. Our The New Way to Warehouse white paper will explain best practices when choosing warehouse automation amid labor shortages and a multi-SKU environment.

Request a demo to learn more about inVia’s unique Totes-to-Person automation system.