Fence-free collaborative robots 4.0

— By Henrik Christiansen, Graphic Robotics

This article addresses the difference between conventional industrial robots and the new small collaborative robots and where it makes sense to use either robots or cobots. Finally, it also addresses what is collaborative, process robot cells in advanced manufacturing.

In the process it appeared that such small robots also could bypass the established robot security requirements (fences, scanners etc.), so suddenly the fence-free robot was born just because of the small robots’ limited performances in speed and payloads.

The university guys founded Universal Robots - and the rest is history. UR quickly cemented its marketing position as the robot manufacturer of fence-free robots (branded collaborative robots or cobots), and even though the conventional robot manufacturers also entered this significant new market, the small UR cobots are today synonymous with fence-free, small and easy to program robots.

What is a collaboration?
Fence-free cobots are per definition slow and with limited power, because otherwise they can´t be close to operators, so the central question is: What is collaboration? The official definition is: Two or more persons working together for a special purpose, which in robotics means that an operator and a robot working together for a special purpose.

The robot industry does not address collaboration but uses its 4-point safety regulation chapter (ISO/TS 15066):

1.   Safety rated, monitored stop
2.   Operator guided robot operation
3.   Speed & separation monitoring
4.   Power & force limitation

Applications based on the 3rd point can have even very powerful robots working in fence-free areas with f.ex. safety scanners. Depending on the operators’ proximity, the robot either slows down or stops when operators enter the area and continues its work, when they leave.

These applications are very suitable, if the operators only enter the area from time to time, but meaningless, if they are there all the time.

Applications based on the 4th point can have operators in the robot’s working area all the time. The robot is allowed to touch but not harm operators, so the robot must be slow and with limited power – and must work with harmless tools and payloads. It must also have built-in pressure sensors, which stop the robot immediately, if a counter pressure from operators is detected.

A dual-arm ABB YuMi robot and operator with safety glasses

These applications are very smart if operators constantly are in the working area, while they make less sense if operators only enter occasionally. The application, not the robot, must be approved as harmless to be allowed as fence-free. And the definition of harmless is both complex and restrictive.

All robot cells can be fence-free
The big misperception among many new robot buyers is that fence-free robots are synonymous with cobots, while the reality is that all robot cells can be fence-free.  Taking fencing out of the equation, the fundamental question is not: “Can there be operators in the robot area?”, but “How often and for how long will there be operators in the robot area?”. Reducing the performance of fast robots for a limited time is much smarter than using slow and expensive cobots all the time.

It is all about performance and price. The going price for an UR 10 (10 kg payload) without tools and programming is around € 35,000, while a comparative price for a Yaskawa GP12 (12 kg payload) plus safety scanner is around € 32,000, and the performance (depending on the payload) is roughly the double. The choice is easy.

A big paradox is that today’s small cobots can be together, but not work together with the operators, so they should not at all be branded as collaborative, but as the market has accepted the label, so be it.

Some examples from the printing industry
In the printing industry several applications with cobots have been introduced recently, f.ex. the Cobostack from MBO. It has been greatly – and fairly - received by the market, because it relieves the operator from lifting heavy materials to pallets. But this is not a collaborative job, because if the robot performs its job well, there is no need for an operator in the working cell except for pallet changes (which also could be automated), and consequently no need for a cobot – but it was chosen, because it is fence-free.

Another example is Rob from Swissqprint, which lifts single sheets from a pallet to an inkjet printer and back again after printing. If the robot performs its task well, there is no need for an operator in the working area, except for pallet changes. The cobot was chosen, because it was fence-free. An even greater paradox is, that for bigger table more flexible solution could have been obtained with a conventional robot with a longer reach combined with a scanner.

In the future all robot cells must be fence-free
Another paradox of URs unquestionable cobot marketing success is that the market now starts to demand that not only simple, easy to program robots, but all robot applications shall be fence-free, so the real paradigm shift in robotics was not the introduction of small cobots, but that their appearance initiated the paradigm shift towards all robot applications shall be fence-free.

The real challenge in industrial manufacturing environments is not how to make a small cobot work together with an operator in a production cell, but: “How do we protect the operators in a total production area with many robotized productions cells, where operators only enter the cells now and then”.  Several software developers are working on solutions, and when they are ready for commercialization, we will see a total paradigm shift in how robots can be used in various industries. And these new software solutions are not far away.

Easiness of programming
The iPhone didn’t kill Ericsson and Nokia because of technology but because of easiness of operation, and URs approach with a kind of iPad concept for programming was very smart (the iPad wasn’t invented when the UR 5 robot was introduced!). But one thing is easiness of programming another thing is: “what can be programmed?” and here are really some differences between the most advanced conventional robots’ and cobots’ controllers - like comparing bicycles to trucks.

The programming tool (teach pendant) for conventional robots looks totally outdated and helps to make programming look complicated. It gives, however, the skilled programmer a huge quantity of possibilities.

The whole cobots concept is focused on simple applications programmed via iPad like programming units, but without a perception of the complexity of specific applications, it is easy to jump to conclusion that small cobots can be used for all kind of applications. They just can’t. Graphic Robotics basically works with very complex applications based on flexible materials such as paper and everchanging flows of new jobs. We have stopped counting the number of times printers have asked us “just to develop a simple robot application for this or that”, because as soon as we just scratch the surface of the application, it immediately starts to be complex. This doesn’t mean that there are no simple robot applications in printing - there are a lot of them - but it means that each application must be evaluated carefully.

The only approach to a successful development of a robot application is to study it very, very carefully before selecting the appropriate robot, not the other way around. If the application turns out to be complex, a robot with a powerful controller as well as complex programming is required, so then it is time to consult professional robot application developers with knowledge within the specific industry. Anything else could end up being very expensive.

Having said this, it would have been good, if the established robot manufacturers had understood the iPhone message in due time, but new generations of teach pendants are coming.

A modular concept where the programming tools, which starts with a very simple display for simple tasks and can be expanded with more sophisticated modules on an “app” basis could be the next level in robot programming.

Hybrid cobots
A logical development is a robot, which is cobot, when needed, and a fast, industrial robot, when needed. Some of the industrial robot manufacturers have developed such hybrids, but one could question the wisdom of such a hybrid, because the application must define if a cobot is required or not. But it is of course always smart to hedge the future and invest in a robot which can be both, if one is unsure of potential future applications.

Collaborative robots 4.0
A robot can only do what it has be programmed to do. Not even the most advanced AI concepts can change this. The must interact with something already programmed.

In the printing industry with flexible materials and ever changing flows of new jobs, the robots can be integrated into production lines as process robots, and then it is impossible to try to program all thinkable alternatives in advance, because there will always occur a new, unpredicted alternative – which not only stops the robot but the total production line. Consequently, the need for the skilled print plant operator to be able to communicate with the robot cell and make appropriate adjustments on the run is fundamental.

Graphic Robotics has solved this fundamental programming challenge by having the basic programs running the robot cell, while the operator can adjust the job-related parameters on the run and in this way communicate with the programs. This is real collaboration.

The interactive Graphic Robotics operator touch-screen

It also means that the total robot cell can be run via a separate screen or via menus on the production line’s operator screen, which makes everything more integrated. No operator should ever be asked to use a teach pendant to operate the robot, so the central topic “easy to program” doesn’t exist, because it is Graphic Robotics’ and other system integrators’ task to develop the robot cell so it can be run via a user-friendly interface.

Collaborative process robot cells can be used in many industries
The printing industry is just one of the industries, which require sophisticated process robot cells with the requirement of on the run operator corrections. The demand for advanced collaborative process robot cells will increase dramatically in the future, simply because the robots’ ever more powerful controllers will expand the possibilities for making such applications.

We have decided to brand this concept Cobots 4.0, so the new paradigm shift in robotics will be real collaborative process robot cells: Cobots 4.0 – and they are already here, because Graphic Robotics has them.

Henrik Christiansen is Sales & Marketing Director and part owner of Graphic Robotics in Odense, Denmark and has long experience in the printing industry. Since 2011 he has worked with robot for the printing industry.