It’s time to rethink Fluid-Power Research

It’s time to rethink Fluid-Power Research

A universal, easy-to-use simulation tool could help fill the knowledge gaps plaguing the fluid-power industry.

The latest issue of International Journal of Fluid Power just arrived at my desk, something I look forward to three times each year. The Journal is published by TUHH-Technologie GmbH and Fluid Power Net at The Technical University of Hamburg-Harburg in Hamburg, Germany ([email protected]). The Editor in Chief, Professor Monika Ivantysynova, of Purdue University, is also coauthor, along with her husband, Jaroslav Ivantysyn, of Hydrostatic Pumps and Motors, an excellent book on the design and control of positive-displacement machines.

Typically, five or six original papers from fluid-power researchers around the world populate The Journal. In addition, there’s an abstraction of Ph.D. theses, as well as a list of recently published books and proceedings —  again, from a worldwide collection of universities, colleges, and researchers. It’s simply become must reading for anyone interested in keeping abreast of the latest research in fluid-power technology.

The Journal’s International Editorial Board reads like a Who’s Who in world-class academic research, with 21 participants from Europe, Asia, and North and South America. Six associate editors round out a compendium of technical dignitaries and universities. The list of engaged people and their respective institutions alone are well worth the €139 (about $200) annual subscription fee. You can visit its Web site at for details.

Monika Ivantysynova. Ph. D. (center) works in her lab with Edat Kaya (left), a lab engineer, and Donnell Cunningham, a student from the Summer Undergraduate Research Program. Ivantysynova has shown how to dramatically improve the efficiency of hydraulic pumps and motors in heavy construction equipment and reduce the machinery’s fuel consumption. Purdue University photo by Vincent Walter.
Education versus training

Clearly, The Journal is a product of academia, a domain where I served for some 25 years as a purveyor of education. For the past 20 years, however, I have been more involved in industrial training. There’s a difference between training and education, and I have my own premise for distinguishing the two. Education teaches people how to think, while training teaches people what to think. We need both, so this isn’t an either-or situation. For now, though, I offer it as a bit of background before making some observations about fluid-power academe, fluid-power research, and the proper application of fluid power to solve industrial problems.

In spite of the important and enlightening aspects of The Journal’s content, few applications engineers I’ve dealt with during my training mode would be interested in the papers. Perhaps even fewer could understand them.

It’s not my intent to offend my many students, research colleagues, and industrial friends. It’s just that researchers often rise to levels far above most of us. In the world of academic research, researchers usually begin from a definition of sponsors’ problems. Then they go about solving them, but discover new problems in the process; then they solve those, which, in turn, uncovers more problems. On and on it goes until a technological disconnect occurs between sponsors and researchers.

We mortals often find it difficult to relate to the problems, much less their solutions. To the extent that I am technically able, I’ve frequently felt that my role was to help interpret the latest research and report in a way that facilitates adoption of the latest ideas. Despite the need for advanced research and application of the most leading-edge mathematical and theoretical methods, it’s my opinion that a critical element is missing. I continue to be frustrated, for example, by the lack of basic fluid circuit-analysis theorems in the working world. We need an Ohm’s law of fluid power.

Oh, yes, some theorems are floating around. In fact, I have my own. You may have yours, and Sylvia and Robert may have yet others. And therein is the problem. We can’t seem to agree on what precise form to give these theorems, so we go from none to too many. It leaves a sizable middle ground between the researcher and applications communities, one that’s not being serviced. There’s a critical need for mathematically basic circuit-analysis techniques that can be taught to undergraduate students and even those vital students in our technical colleges.

Expand the educational base beyond vendors

The Journal’s content — plus all other research that isn’t reported — require, I would guess, multimillion dollars of support annually. Meanwhile, the fluid-power industry continues to lose ground to its competitors in the electrical-electronic drives business. At risk of oversimplifying, I suggest that the electrical industry is represented by an educated and knowledgeable distribution and sales network serving an educated and knowledgeable marketplace. As a recovering electrical engineer, I can tell you that they’re not 10-ft tall. However, there are far more electrical and mechanical engineers than there are fluid-power engineers.

In the fluid-power industry, the educated and knowledgeable base exists largely on the vending side of the marketplace equation and in a few large original equipment manufacturers (OEMs). Customers are usually engineers or technicians with diverse areas of expertise and education. They are assigned a project because of a single or new incoming machine or process — yet they have precious little command of hydraulics or pneumatics technology. They may be required to work with many specialties, including fluid power, but ultimately must depend on their vendors for technical expertise. Is this by design or by default, or due to the wrong emphases in academia?

We can’t ignore the reality that the detailed technology exists with the vendors, and it’s unlikely to change in the near future, if at all. Therefore, it seems to me that what we need isn’t so much research on how to make mathematical models and intricate simulations on the progression of pressure variations while the piston transitions from the low to high-pressure side of a pump or motor. Such studies, will help with noise control and efficiency and, more generally, with pump and motor design. However, there’s little direct benefit in expediting systems applications. Instead, we need teachable analytical tools at the undergraduate and technician levels.

Wanted: A practical simulation tool

If simulation, for example, is a powerful tool for predicting all manner of dynamic system responses (and I know firsthand that it is), then we really need some sort of easy-to-use, affordable simulation tool for today’s applications engineers. It must be a single tool built with an intuitive interface that’s readily available without weeks or months of specialized training. It also must fit comfortably among the scores of other tools in an applications engineer’s toolbox. And its ease of use must be to the point where if the tool remains inactive for several weeks, it won’t require retraining when needed again. On top of that, rocket science shouldn’t be required to carry out the simulation.

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Can academia play a role? I think so. Lots of research is needed to settle on the nature of the user interface, and academia has the talent pool to develop the database of component mathematical models. They also can teach first principles.

Can vendors and developers of simulation programs help? I think so. They could write special user interfaces that utilize the language of fluid power, not the language of simulation. General-purpose simulation programs are too expensive and require too much support and specialized training.

Can the Fluid Power Society (FPS) contribute? I think so. These technical specialists can benefit most from having powerful, easy-to-use analytical tools at their immediate disposal. Moreover, their members are part of the technical talent pool. Computer-aided system analysis and design tools are vital to successful applications, to the point where it warrants a new specialty certification program. What about FPS being a source or clearinghouse for special simulation talent, relieving the software vendors of that costly burden?

Can the manufacturers and distributors make an impact? I think so. They have a lot to gain, but more importantly, they have the most to lose from botched applications and the ever-growing proselytization and encroachment by the electrical-machinery industry. Lest we forget, too, that the chances of failure increase as the technological level increases (e.g., electronic controls, closed-loop feedback control systems, and motion-control technology).

Can the National Fluid Power Association contribute? I think so. They could help define and standardize the language and interfaces of simulation. They also could help standardize component mathematical models without divulging proprietary design information, as well as prepare a universal database of standardized models. Indeed, because NFPA is a group of fluid-power manufacturers, it’s the logical choice for cultivating a universal simulation tool and universal simulation language, much as Spice has become the simulation tool of choice for the electronic industry.

It must be emphasized that electronic-circuit designers can go from a simulation to a chip foundry without ever having to build a prototype or breadboard. We in fluid power are not close to that utopian scenario, but it’s a worthwhile goal for the industry. Manufacturers, users, and OEMs would benefit from such a universal tool. The ride is just beginning. I encourage you to jump on board!

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