So you have read an article declaring Collaborative Robots, or Cobots are the new big thing in automation.  That they are revolutionising industries being more user friendly, flexible and with a lower cost of install, what’s not to like?!

Well there are two sides to everything and the narrative that “traditional” robot systems are being left behind and Cobots are the future doesn’t always hold up. Robot automation is always a bit bespoke and there will be many ways of accomplishing the same task. Collaborative robots certainly have their place, are opening up new markets and getting good press but sometimes a more traditional robot install will be a better and cheaper solution, so lets compare.

Force

If you are looking for speed, agility, accuracy and power then a “traditional” robot is winning every time. Those same force limitations that make Cobots safe to work alongside also limit their capabilities, a lot. F=ma so a drop in force means a drop in effective payload (mass) and/or acceleration which in a robots limited work envelope means a drop in speed and an increase in cycle time. On the other hand Cobots are great for many applications where speed is not the primary concern.

Rigidity

Just look at the weight of a Universal Robots UR5, a mere 18.4kg compared to an ABB IRB1600 at 250kg. The ABB is certainly going to be stiffer, there is just more metal in there. Ok, you are going to need a stronger gantry to hang the ABB from but if you are doing anything that requires the robot to be rigid then it’s a simple choice. In fact you could bolt the UR5 to the back of a IRB1600 and it should be fine (I will have to try that sometime).

Ease of use

This is supposed to be the Cobots forte yes? Well sometimes, maybe, but the traditional robot controller has two advantages: First there is often a huge number of additional software modules for many operations. So if you are doing an operation like MIG welding then a Cobot is unlikely to have the control you need. Secondly most applications will need a dedicated HMI anyway and so, day to day, the simplicity of the pendant UI is unimportant while it is stuck on the holder unused. When you do need to do some serious programming then the extra “complexity” of a traditional teach pendant makes programming quicker and easier for experienced users.

Cost

Yes… Cost. You should be saving money on guarding, the aforementioned HMI, light curtains, safety scanners, not to mention a load of metalwork to mount the robot on…. shouldn’t you? You should – except that the costs of all these parts are dropping significantly. You will still need grippers, tooling etc and the robots themselves are often very similar in price. In fact a small non-collaborative robot is often significantly cheaper than a cobot. But you’ll save money on the install right? Er, probably not much. A good integrator will cost you a bit up front but they will save you a lot of time and money in development, regardless of robot type. Going all DIY with robotics maybe a fun project but there is rarely a strong business case for reinventing the wheel.

Safety

The beauty of Cobots is that they are safe enough to work alongside. If they run into you they may cause a bruise or maybe break a finger but they won’t kill you, lovely. However would you be happy if your co-worker whacked you every few hours? I doubt it, and I’m sure they would be on the end of some stern words from HR. Although the considerations for ISO/TS15066  are good and constructive, realistically the human in the human-robot collaboration has to take precedence and surely – not get whacked at all. Relying on force feedback from the motors is always going to be too little too late and should not be the primary safety measure but a failsafe. Besides which sensors already exist to slow robots down safely without disrupting the process too much long before contact occurs. Also the guards are there to keep people out, not to keep the robot in. I promise you if that 500kg payload robot wanted to escape it could.

 

There are definite use cases for collaborative robots and the technology is developing rapidly to make robots cheaper, safer and easier to use – collaborative or not. This is the direction of the industry. But to sum up it is well worth considering, on a case by case basis, whether a Cobot is the right tool for the job. A more “traditional” robot install maybe better in every practical way.

For all UK companies that are looking to automate with robotics we offer a free consultation. We will be happy to review your processes and help you choose the best approach to automation. Robots are more affordable and easier to use than ever before.

Is collaborative always the right choice?