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Cobots: finding their place

09 November 2020

Suzanne Gill asks where cobots might offer the most value in today’s manufacturing processes and finds out what work is being undertaken to ensure their trustworthiness. 

According to Nicolas Lauzier, senior product manager at Robotiq there is an increase in the use of cobots across a broad spectrum of applications, due to their flexibility. He said: “While companies may use standard industrial robots for their day-to-day operations, the deployment of cobots is burgeoning in applications where greater flexibility is needed – but not at the expense of volume or performance. This is particularly the case in applications where products are currently being handled manually, meaning significant alteration or reconfiguration of the physical production environment is not needed.” 

According to Lauzier, one of the key factors behind the growth in cobot deployment is the ready availability of simpler and more cost-effective systems comprising standard hardware, tooling and ancillary components. These, he says represent an attractive alternative to larger, fixed automation systems. 

Palletising choices
In the area of palletising, for example, the robotic automation choice has traditionally been between ‘bundled’ systems – comprising a range of components from different suppliers packaged as a standard solution – or working with a supplier to create a bespoke solution based on an arbitrary productivity target. “Bespoke solutions often result in extended development and testing time, creating a system which may be challenging to reconfigure or redeploy should requirements alter in the future,” continued Lauzier. 

“However, using standard products for a cobot application allows for more rapid simulation of the application – its feasibility, predictability, likely throughput and payback time. Many providers now offer online configurators which allow an analysis to be undertaken based on part dimensions, weight, required throughput and so on. This approach also allows for more rapid risk assessment compared with more complex systems comprising components from different suppliers where there may be no universally compatible software. Here, any alteration to the application will require a completely new risk assessment, at potentially significant expense and delay, to assess the effects of the new application on the production environment and those within it.” 

Lauzier offers a typical cobot application example – in a food & beverage or consumer goods facility – where standard products manufactured all year round are handled on specific palletising lines by larger, in-situ robot systems. Here, occasional or specific applications – for example Christmas goods, or items specific to one customer, with a different box dimension – can be undertaken by a standard cobot system which can be rapidly reprogrammed and redeployed once that particular requirement has been fulfilled. 

He offers another example that demonstrates the value of cobots, in bin-picking for machine tending applications in the automotive sector, where components for different vehicles may be similar but not exactly the same. “Here, investment in a bespoke part feeder would not be appropriate – even if this could be altered for other parts, it may be a lengthy process. But standard software can be used to reprogramme a cobot to handle components of different dimensions without significant downtime,” he said.

Working together
Oliver Giertz, product manager for servo/motion and robotics for the EMEA region at Mitsubishi Electric, agrees that cobots offer a good solution to meet the current need in manufacturing for more flexible systems, driven by the rise of high-mix low-volume production. “By working together with humans to enhance new and existing production lines, cobots can help companies meet this demand,” he said.
 
Designed to assist human operators on the shop floor, cobots can take on simple, repetitive and physically strenuous tasks. This offers improved consistency and reliability in manufacturing while enabling humans to concentrate on more complex jobs. A cobot is also flexible and can quickly learn to adapt to a variety of tasks – from picking and placing to machine tending. 

According to Giertz, the line between industrial robot and cobot is becoming less defined. He said: “Some industrial robots can limit their speed, range of movement or torque when safety sensors are activated, allowing operators to move into the same workspace without physical guards. The robot will slow down and then halt when the human, or other moving object comes too close. A key attribute of the cobot however is that they can continue to operate alongside humans, including physical manipulation by the human operator – in this case the pause in motion is momentary. 

“When deployed for working alongside humans, cobots don’t require physical safety guards. This means that production lines can benefit from increased automation in a more compact space. This also requires a greater reliance on safety functionality.” He goes on to point out that recognised standards, such as the TÜV safety certification for the ISO/TS 15066:2016, are being used to clearly define this. Overall safety processes must also be in place to limit access to programming functions, such as protecting settings with a password and log of the time as well as date. Additionally, appropriate risk assessments need to be conducted before working with a collaborative robot.

Giertz believes that a key area of value for cobots within manufacturing processes is their ability to work flexibly across a variety of tasks. “Frequent redeployment means that they need to be fast to set up, without requiring robotic programming expertise. A new development which can improve the ease and speed of configuration is hand-guided teaching, where the cobot arm is simply moved to the desired position and added to the operational sequence at the press of a button. This technology means that no complex programming is required, it can also be combined with touch-screen graphical interfaces to implement more sophisticated operations. 

“A digital twin can also be used to enhance the speed of set-up and redeployment. Employing a digital representation of the physical cobot, including the virtual capability to evaluate performance, the digital twin can simulate cobot interaction to ensure that it can safely and predictably fulfil the desired task before deployment. 

Difficult environments
For basic, simple and repetitive tasks cobots can be the perfect choice of worker. Ian Hensman of Kawasaki Robotics (UK), points out that this is especially true if the working environment is hostile, space is at a premium or guarding causes access issues. Likewise, if the materials or products being handled are not pleasant to work with or are potentially hazardous. “Here, a cobot just gets on with the work, 24/7 if need be, without a break and will do things exactly right first time, every time,” said Hensman. However, he goes on to point out that having cobot technology and continuing to develop it is one thing, but gaining wider acceptance of the principle of employing cobots is quite another. “I don’t think that many of us involved in cobot technology will dispute one thing: that customer and user perception is sometimes hard to overcome, despite the maths showing clear financial advantages for the immediate deployment of cobots. It is an odd ‘social’ viewpoint.”  

Hensman believes that the future of cobots depends on how the terms of reference for a cobot evolve and are interpreted. For example, which tools are acceptable to remain a cobot and which tools might turn a cobot into a robot operating under a completely different set of rules for the workplace? “Our technical, engineering and industrial past shows that the widespread acceptance of some new technologies can take a very long time and is often far from being a straight path. There is a need for those in the cobot business to continue to present a united front to gain acceptance and to persuade potential users that that cobots have a vital part to play in so many applications and environments,” concludes Hensman.


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