Jan Camiel Willems | |
|---|---|
| Born | (1939-09-18)18 September 1939 Bruges, Belgium |
| Died | 31 August 2013(2013-08-31) (aged 73) |
| Alma mater | Massachusetts Institute of Technology; University of Rhode Island; Ghent University |
| Awards | IEEE Control Systems Award; Honorary doctorate,University of Liège |
| Scientific career | |
| Fields | Mathematical Systems Theory; Electrical Engineering |
| Institutions | University of Groningen; Massachusetts Institute of Technology |
| Doctoral advisor | Roger W. Brockett |
| Notable students | Keith Glover; Arjan van der Schaft; Henk Nijmeijer; Harry Trentelman |
Jan Camiel Willems (18 September 1939 – 31 August 2013) was a Belgian mathematical system theorist who has done most of his scientific work while residing in the Netherlands and the United States. He is most noted for the introduction of the notion of a dissipative system and for the development of the behavioral approach tosystems theory.[1]
Jan Willems was born inBruges in 1939. He studied engineering at theUniversity of Ghent, obtained the M.Sc. degree from theUniversity of Rhode Island, and the Ph.D. degree from theMassachusetts Institute of Technology inelectrical engineering in 1968. He was an assistant professor in the department ofelectrical engineering at MIT from 1968 to 1973. On 1 February 1973 he was appointed professor of systems and control in the mathematics department of theUniversity of Groningen. In 2003 he becameemeritus professor. Afterwards, he became guest professor at theKU Leuven. He served terms as chairperson of the European Union Control Association and of the Dutch Mathematical Society (Wiskundig Genootschap). He was managing editor of theSIAM Journal of Control and Optimization and as founding and managing editor ofSystems & Control Letters.
In his Ph.D. dissertation, Willems worked on input/output stability. In an often-cited 1972 paper[pub 1] he introduced the notion of adissipative system. This notion is a generalization ofLyapunov function to input/state/output systems. The construction of the storage function, as the analogue of a Lyapunov function is called, led to the study of thelinear matrix inequality (LMI) incontrol theory. Applied tolinear-quadratic-Gaussian control, the construction of the storage function leads to theKalman–Yakubovich–Popov lemma. In the 1980s Willems worked on the geometric theory of linear systems, where he introduced the notion of almost invariant subspace. Since the 1990s, he has devoted his interest to the development of the behavioral approach to systems theory and control.[pub 2][pub 3] In the behavioral approach a dynamical system is simply viewed as a family of trajectories. This approach avoids having to separate the system variables into inputs and outputs.
Willems was a fellow of theIEEE, theSociety for Industrial and Applied Mathematics, theAmerican Mathematical Society[2] andInternational Federation of Automatic Control. In 1998 he was an Invited Speaker of theInternational Congress of Mathematicians in Berlin.[3] In 1998, he received theIEEE Control Systems Award "for seminal contributions to control theory and leadership in systems research". In 2010, he became doctorhonoris causa of theUniversity of Liège.
