The world of automated guided vehicles (AGVs) and autonomous mobile robots (AMRs) can appear complicated. This quick guide explains what an AMR or AGV is and outlines the most common different types of them available today.
What is an automated vehicle?
An automated guided vehicle or AGV is a mobile robot that follows a series of predetermined instructions, cues or signals to move around a site and complete actions autonomously, such as picking up or dropping off materials.
AGVs and autonomous mobile robots (AMRs) are different, even though some people in the industry use these terms interchangeably. The U.S. safety standard for industrial mobile robots defines the difference between AGVs and AMRs as “how they traverse the specified operating environment.” An AGV moves through an environment by following predefined guide paths — either virtual or physical — and uses collision avoidance (stopping and waiting in case of a blockage). By contrast, AMRs can set their own paths and use obstacle avoidance to navigate around blockages.
Generally speaking, the types of AGV listed below use the classic AGV ‘stop and wait’ approach to dealing with blockages. Below are the four most common types of AGV on the market today.
The four most common AGVs
The first is underride AGVs, which drive underneath payloads (carts and trollies, for example) from point to point. They are also known as automated guided carts (AGCs), self-driving carts, under-cart AGVs, or mouse AGVs.
Underrides connect to their payloads in a variety of ways, such as via tow pins and lift modules. Some underride AGV models also function as tow tractors by hitching to trains of carts. They are used in material handling and manufacturing applications, for example, to move semifinished goods between different production stations. They are often deployed in large fleets, most notably in automotive production.
Simple in design, these low-profile robots are flexible and relatively low-cost compared to other types of AGV such as forked models.
Tow tractors, the second type of AGV, hitch to payloads, such as carts and other logistic trains, with a typical application transferring parts to an assembly line. Also known as tugger, tractor or towing AGVs, they offer towing capacities of up to several tons and because they offer high throughput by moving several carts at one time.
Many tractor AGVs are actually automated versions of human-driven vehicles. These may also offer hybrid operation, allowing a worker to take over and drive if required.
Unit load AGVs are a third common type, and they carry their cargo on top. They are available with different transfer devices, such as conveyors and lift platforms, and are found most often in production and warehouse facilities.
Unit load AGVs are available in many sizes, and they are capable of carrying a diverse range of payloads. Unit load AGVs are used to transport everything from light goods and pallets to robotic arms, truck tires and multi-ton steel coils. They are also known as unit load carrier AGVs, unit load deck AGVs, and turtle AGVs.
The fourth common type is a forked AGV, which refers to any automated guided vehicle with forks. These vehicles, also known as fork AGVs, forklift AGVs, and pallet truck AGVs, perform similar types of tasks to automated forklifts: lifting and transporting materials and goods (typically, pallets).
It is important to note, however, that while automated forklifts (also called automated guided forklifts or AGFs) are robotic versions of existing, manually driven forklift trucks, forked AGVs are not. In contrast, they are designed for automated operation only. Therefore, forked AGVs do not offer hybrid operation, and they cannot be manually driven if needed.
Numerous types of forked AGVs are available, from pallet truck AGVs to counterbalance, reach truck and very narrow aisle (VNA) models. While forked AGVs cost significantly more than their manual forklift equivalents, their efficiency benefits often lead to a significant return on investment, often in as quickly as one or two years.
Common types of AMRs
The most common types of autonomous mobile robots (AMRs) in general do not differ much from AGVs. The most common are:
- Underride robots (automated guided carts or AGCs, analogue to underride AGVs)
- Unit load carrier robots (analogue to unit load AGVs)
- Forked AMRs (analogue to forked AGVs)
- Picking robots
To reduce handling times in distribution centres, picking robots can be used as goods-to-person pickers to bring product bins to the human pickers or to pick orders from the human pickers in the aisles themselves. Picking robots typically have a fixed-height platform on which various containers can be connected or placed. Navigation of many picking robots uses QR or other codes/tags on the floor, not on the natural navigation. - Sorting robots
Sorting robots can sort products into pre-programmed batches. This is useful, for example, to transport them to an outbound and shipping zone or to place goods in the correct bin in a fulfilment centre. Sorting robots have a range of trays, crates, and racks, as well as connection mechanisms. These robots also navigate via QR codes and tags on the floor.
*This blog article is based on content kindly provided to us by BlueBotics.
