The pneumatic-electrical dynamic in motion control

22 September, 2016

Guzzoni also makes the point that despite the increasing prevalence of electrical motion control, pneumatics continues to play a highly significant role. “It wouldn’t be incorrect to say that 95 per cent of cases with movement requirements can be solved with the conventional, reliable, cost-effective and simple pneumatic cylinder,” he said. “The position reached can be checked by a similarly conventional magnetic sensor. Anybody who produces pneumatic components can sleep soundly in bed at night.”

Something that has seen some of the most rigorous development in recent times is the modern industrial robot. Edwards considers one of the advantages of a robot over a special-purpose piece of equipment is its inherent flexibility and its ability to be reprogrammed to undertake a range of different tasks. This is where Edwards believes electronic and electrical actuation systems come to the fore. However, in areas such as end-of-arm tooling, he believes pneumatics can play a highly significant role; for example, a vacuum system to pick up items such as metal sheets or car body parts. “In this way, robotics can be a good example of a hybrid electrical-pneumatic application,” he said.

Maintenance, repair and replacement

From a maintenance, repair or replacement perspective, Edwards comments that when providing solutions into developing countries pneumatic solutions can have an advantage because they are easy to understand and can often be maintained with simple tools. “On the other hand, if something electrical breaks down you may need to fly in a service engineer a considerable distance in order to replace them,” he added.

In terms of lifecycle of a pneumatic actuator, Edwards points out that users will generally see a progressive deterioration in performance towards the end of its life. “It will start to get stiff and may start to leak,” he said. “However, through condition monitoring users can keep on top of this type of issue and, for example, allow the machine to finish a run before servicing it over the weekend. In the case of an electric actuator, it may operate effectively throughout its lifecycle, but if it fails, it may do so without warning and the machine will immediately cease to function until a replacement actuator is fitted. So, depending on the application this can be a consideration when choosing pneumatic or electric actuation.”

Keeping safe

From a safety perspective, Edwards points out that many mining applications are largely or completely pneumatic in order to reduce the risk of a spark inside a potentially explosive atmosphere. “This can be more convenient than trying to encase everything within an electric application,” he said.

With regard to regulatory requirements concerning safety, Edwards believes it can be an advantage to have both pneumatics and electric control options in place in order to eliminate the potential for a single failure mode. “In this way, companies that deploy an electric solution with a pneumatic backup or vice versa, can rest easier if they lose their power supply,” he said.