We briefly mentioned about collaborative robots (or cobots) when we introduced the different types of industrial robots. In fact, some would argue that cobots by design do not belong to the category of industrial robots. In this article, we give the special attention which cobots deserve and expand our discussion into four aspects of interest.

Brief History

Universal Robots launched their first product, UR5, in 2008. This is regarded as the revolution of the market for industrial robots and sets the standards of cobots. The design, functionalities and usage of cobots created a new era in terms of installation, process engineering and applications. Over the years many other manufacturers look to UR for product design and specifications.

In recent years, more applications of cobots have been developed and they have started to replace industrial robots in some areas.

Safety

Cobots are designed to work alongside humans. In 2016, the International Organization for Standardization (ISO) created their first technical specification for collaborative robots: ISO/TS 15066. This Technical Specification supplements and supports ISO 10218, which is the original safety standard for traditional industrial robots. It provides guidance on the design of cobots and their operations, particularly the integrity of a safety-related control system with monitoring, stopping, and risk reductions measures through process parameters.

The ISO/TS 15066 publication was last reviewed and confirmed in 2022 while other safety standards also exist. As cobot products evolve (and very quickly too) the challenge is to exhaust the applications of cobots while maintaining coherence in their safety requirements. The ISO 10218 standard is also being revised at the International Robot Safety Conference in October 2024.

Small Footprint

A very good reason to use cobots instead of industrial robots is that they can save space. No safety barriers means much smaller footprint in the factory. When the footprint of a robot cell is typically twice of a robot’s arm length squared, the space taken per robot becomes quite sizable with much of it inside the cell not being used at a given instance of time. Cobots can be placed more densely in a limited space. In fact, the bigger cobots get to, the more factory space they can save. This is the reason that cobots are desired to be bigger, and when they are used for jobs not necessarily collaborative with human.

Low Cost

Cobots are usually more cost effective than traditional industrial robots. They use less space and have lower running costs as they consume less energy. They also require less maintenance, with some manufacturers even promising Zero Maintenance for a number of years. It goes without saying that there is no need to pay for safety barriers.

Payload

When cobots first became available, they were designed to handle a small payload. UR5 can lift 5kg and most cobots were in the 3kg to 10kg range. This changed in the late 2010s when the 12kg, 16kg and 18kg payload cobots were launched and soon became the norm across manufacturers. For quite some years (until recently!), cobots were considered to have a low to medium payload typically below the 20kg mark.

We need to mention that during this early period, FANUC introduced their first ‘industrial cobot’ CR-35iA in 2015. This robot weights close to a ton and has an impressive 35kg payload (heavy for cobots!). Although fixed with force stop sensors, its size and heavy duty looks (albeit in green) didn’t convince the market enough, at least at the time, to recieve it like other friendly looking cobots.

However, things have changed fast since the 2020s. The Covid-19 pandemic meant more automation and human-robot interaction were needed. Cobot manufacturers soon found themselves competing in the so called industrial cobots (yes it’s a thing, as both FANUC and UR endorse this term) racetrack with 20kg or higher payloads. So FANUC has been proven to be a step ahead after all!

UR20, Doosan H2017, AUBO i20, FANUC CRX-20iA and a few others all came with 20kg payloads. They have also got a bigger reach as much as 1750mm. UR30 (through a software update in October 2024), AUBO iS35, and NEURA MAiRA XL now have a 35kg payload, and AUBO iS35 has also broken the length record with a reach of 2100mm. The cobots certainly didn’t take long to increase dramatically their payload capacities in just several years.

Conclusion

We discussed how collaborative robots (cobots) differ from traditional industrial robots. Cobots are definitely utilised more in applications that don’t demand high payload capacities or high precision, whether or not they collaborate directly with humans. While traditional industrial robots may face increased competition from cobots, this competition can benefit robot users eventually. As safety standards remain a priority, we expect to see industrial regulations catch up with the latest advancements in cobots very soon.