Guest Commentary 2-16-98

February 16, 1998

GUEST COMMENTARY Exclusive interviews with technology leaders

Charting the growth of servopneumatics

Hosrt Saalbach, President Festo USA

Most engineers know the widely accepted reasons for selecting pneumatic systems: Pneumatic components provide high force and high speed at relatively low cost. Recently, however, pneumatic systems have begun offering a new wrinkle: Mid-stroke positioning, with accuracies that would have once been considered impossible. Design News asked Horst Saalbach how these developments in pneumatics will affect the future of automation.

Design News: When engineers have a motion-control problem, their first inclination is to think of electric motors and drives as a solution. How do you intend to educate them about the advantages of servopneumatics?

Saalbach: There has been a noticeable increase in the number of enlightened engineers in the past decade who have availed themselves of emerging technologies. Now more than ever before, industry is in need of the most cost effective way to produce increasingly more complex and miniaturized parts and assemblies, and to provide adaptive positioning equipment for applications involving pick-and-place, dispensing, and packaging. This has led to a more in-depth investigation into servopneumatics as an alternative to more costly motor-control solutions.

Q: Are engineers starting to get the message--in other words, have you seen an increase in the use of servo-pneumatics in recent years?

A: Servopneumatics have evolved over the past 10 years, and with that evolution we have experienced geometric increases in inquiries from both new and existing customers. Our face-to-face experiences with potential users have resulted in spirited exchanges of information, and we have determined that a great deal of effort must be concentrated on educating the market. We've discovered that there are tiers, or levels of acceptance, that this technology must survive. But once the equipment proves itself, the rest is academic, because it is cheaper and every bit as reliable as the industry-standard electric motor.

Q: What kind of applications are you targeting right now for servopneumatic solutions?

A: This must be answered from a generic standpoint because intelligent motion applications are so diverse. We have determined that, with respect to accuracy and payload capacity, nearly 70% of the intelligent-motion market can potentially be served by servopneumatic technology. Like all intelligent-motion solutions, their suitability must be evaluated on a case-by-case basis. Our experience has revealed, however, that particular interest has been shown by the packaging industry, as well as part-handling and assembly. However, it must be stated that nearly all industrial sectors could potentially benefit.

Q: Is there a subset of motion control applications where servopneumatics is clearly not the best solution?

A: Generally, the following types of motions are not good candidates for servopneumatics: Multi-axis interpolation; multi-axis applications requiring vector-velocity regulation; velocity tracking; and motions requiring extremely slow speeds with large payloads.

Q: How much do you expect servopneumatics to grow during the next five years?

A: As we see it, the growth of servopneumatics is highly dependent upon a continuous education program. Efforts are directed at understanding the obstacles not only of the technology, but of the dynamics of penetrating a cautious and inquisitive market. As industry continues to realize that not every positioning application requires a servo or stepper motor driving a lead screw under the direction of a sophisticated numerical controller, and all the cost that goes with it, servopneumatics will come to rule in its own domain.

  Therefore we suspect that market acceptance and product identification are closely linked, and as the need arises, servo-pneumatics will grow in geometric proportions in low- to medium-accuracy positioning and high speed applications.

Q: In terms of performance, how much better can servopneumatics get?

A: As this technology is increasingly accepted by industry, improvements in performance will be inevitable. These improvements are most likely to focus on actuator design and loop-control algorithms. More immediately, however, will be the second generation systems that are more user friendly in terms of implementation. Improved software, modularity and set-up will make this product more accessible.