Great Gold Medal awarded to Lennart Ljung

For more than 40 years Lennart Ljung has been one of the most prominent professors at Linköping University, in both Swedish and international contexts. He is now to receive the Great Gold Medal from the Royal Swedish Academy of Engineering Sciences (IVA) for his pioneering work in automatic control. 

Lennart Ljung in the town hall in Stockholm Lennart Ljung together with Torsten Persson, Rune Andersson och Anne-Marie Eklund Löwinder Vinger Elliot Fotografi

This is the most prestigious award given within engineering sciences in Sweden. “A Swedish Nobel Prize in Engineering”, says Lennart Ljung proudly. He became professor at LiU in 1976, and added the title “emeritus” in 2011.

“IVA has mainly awarded its Great Gold Medal to business leaders. Around 20 have been awarded to researchers through the years, and it’s a true honour to receive it”, he says.

It is also the first time the prize has been awarded to a researcher at Linköping University.

Automatic control has been an area of excellence at the university since Lennart Ljung chose to leave his postdoc position and career at Stanford University in 1976 to become Lennart Ljung med IVA:s Stora guldmedaljLennart Ljung Photo credit Ann-Kristin Ljungprofessor at the newly established university in Linköping. The decision was also taken for family reasons to a certain extent: neither he nor his wife was attracted by the idea of bringing up children in the US.

Automatic control central in WASP

“One of the first people I employed in the division in 1977 was Mille Millnert”, Lennart Ljung remembers.

Mille Millnert is professor in automatic control, and has been vice-chancellor at LiU. He spent some years as director general of the Swedish Research Council and then a few years ago became chair for Sweden’s largest individual research programme WASP (the Wallenberg AI Autonomous Systems and Software Program).

“Automatic control is central to WASP”, Lennart Ljung states.

He is not himself active within WASP, but is following the programme closely. For example, one of his former doctoral students, Fredrik Gustafsson, who is now professor of sensor informatics in the Division for Automatic Control, is the professor who currently has the greatest number of doctoral students within the WASP programme.

Lennart Ljung defines “automatic control” as making systems and equipment behave as we want them to, and this definition is extremely broad.

“They may be biological, financial or technical systems. The ABS brakes in cars and stabilisers in trains are examples of systems with pure automatic control. It’s a case of being able to control the systems in the long-term, and this is not possible without continuous feedback. The principle of feedback is crucial within automatic control”, he says.

System identification

When Lennart Ljung started his research career, system identification was in focus to create models of the systems then in use. The systems have subsequently become increasingly complicated and complex, and what previously could be dealt with by automation has become the subject of autonomous control.

The theoretical models must unite computer science and artificial intelligence with visualisation, automatic control and sensor informatics. A symbiosis of the various fields of science will enable possibilities in the control of large and complex technical systems, such as unmanned aerial vehicles, autonomous cars, and industrial processes.

“We’re not there yet, but work is ongoing, and one prominent forum for this is WASP. And this is a field in which results are rapidly absorbed by industry”, he points out.

Research into questions that are relevant for industry is characteristic for Lennart Ljung. His research career contains a unique combination of deep theory and practical applications, as the IVA citation points out.

Many awards

As a young man aged 72 years, Lennart Ljung has taken his foot from the accelerator somewhat, and enjoys life in his summer house at Österlen, while often taking cruises with his wife. He remains, however, continually productive in science. The systems are becoming evermore complex and their network connectivity is increasing, which means that the models must be continuously refined.

“I probably publish just as much as I have always done, these days mostly with international co-authors. But it is very relaxing no longer having to pull in SEK 25 million every year in funding. No one here at the division depends on me now”, he says.

Principal supervisors for doctoral students must be younger than 65 years, but Lennart Ljung is assistant supervisor for two. He is also a member of the committee that assesses applications to the European Research Council, ERC. “It’s an interesting job, and there are many applications this year dealing with network connectivity.”

Lennart LjungLennart Ljung Photo credit Ann-Kristin LjungThe Great Gold Medal of IVA is, however, not the first award Lennart Ljung has received during a career spanning nearly 50 years. He has been awarded several international prizes, including those from the International Federation for Automatic Control, IFAC, and from the Institute of Electrical and Electronics Engineers, IEEE Control System Society. He has received honorary doctorates from no less than five institutions of higher education. He has been a member of the Royal Swedish Academy of Engineering Sciences (IVA) since 1985, and of the Royal Swedish Academy of Sciences, KVA, since 1995.

The IVA citation

Professor Lennart Ljung has been awarded the IVA Great Gold Medal for his fundamental achievements in the field of control theory – ranging from deep theoretical contributions to direct industrial applications. He has developed new methods to construct mathematical models of industrial and other systems, and has developed software that is used all over the world. His close collaboration with industry has ensured that many Swedish companies enjoy competitive advantage in international markets.

Translation George Farrants

Lennart Ljung at Town hall in Stockholm

In the Blå Hallen, town hall in Stockholm. Vinger Elliot Fotografi

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