Yakov Z. Tsypkin

Yakov Z. Tsypkin


Friday, September 19, 1919

Passed away: 

Tuesday, December 2, 1997

Yakov Tsypkin, in full Yakov Zalmanovich Tsypkin, is a landmark person for the Institute of Control Sciences (the former Institute of Automation and Remote Control (IARC), the USSR Academy of Sciences; nowadays, Trapeznikov Institute of Control Sciences, the Russian Academy of Sciences). Tsypkin played a key role in scientific life and much contributed to the special moral climate of the Institute’s unique staff.

His inclination for research appeared quite early. Tsypkin published his first papers at the age of 20 as a student at the Moscow Institute of Communications. Subsequently, there were the Great Patriotic War, a heavy wound, surgical operations, and a hospital, where Tsypkin continued to study and think about problems that further underlaid his dissertation. In 1945, he defended the candidate’s dissertation in engineering at IARC. In the post-war period, Tsypkin’s profile as a researcher was much formed by Andronov’s Seminar at the IARC. In 1948, Tsypkin defended his doctoral dissertation in engineering (again at IARC), and Academician Andronov was his opponent. In those years, Tsypkin was apparently the youngest Dr. Sci. (Eng.) in the USSR; a year later, he became Professor. In 1950, Tsypkin started working at IARC. From 1956 until the last days of his life (over 40 years), he headed Laboratory No. 7 (Adaptive and Robust Systems) of the Institute.

His research covered five main areas.

The first one was systems with delays. In 1946, Tsypkin published a paper on this subject in Automation and Remote Control. (It was the first of his 75 publications in the journal; the last one, posthumous, appeared in 1999.) He proposed a generalization of the Nyquist criterion in the case of delay. This result was very important: its translation into English was included in a prestigious foreign book on frequency methods in control theory, immediately after the Nyquist seminal paper. Interestingly, some of his ideas turned out to be fruitful much later, in the 1990s, when developing robust stability criteria for systems with delays.

In 1948, Tsypkin began to study impulse systems (or discontinuous control systems, presently known as discrete systems). The research results in this area made Tsypkin famous worldwide. In recent decades, discrete systems have played a huge (and still growing) role in engineering and technology, particularly digital control and computers. Tsypkin developed an adequate mathematical apparatus for studying such systems, the z-transformation method (the Laplace discrete transform). Tsypkin along with American scientist E.I. Juri are considered the founders of the theory of linear discrete systems. In 1951, he published the first book on impulse systems, followed by many others. Many Tsypkin’s books on the subject were translated into foreign languages.

The third research area is connected with relay systems. His first publication on this problem appeared in 1952. It considered systems with relay control (only two possible values of the control variable). Such systems are inherently nonlinear; nevertheless, for their analysis, Tsypkin applied the theory of linear systems with a high gain. His monographs of 1955 and 1974 on relay control included such important results as the Tsypkin criterion and the Tsypkin hodograph (also called the Tsypkin frequency locus). These results received a great response after developing optimal control methods when the relay character of control actions turns out to be typical.

In 1965, Tsypkin completely changed his research interests. In those years, “adaptation,” “learning,” and “recognition” became very popular, but the exact meaning of these terms was unclear. Tsypkin proposed a unified approach to studying such systems based on recurrent stochastic algorithms and the apparatus of stochastic approximation, already developed in mathematical statistics. The first plenary paper by Tsypkin on this problem (at the 3rd All-Union Conference on Automatic Control, Odessa, 1965) aroused great interest and a vigorous discussion. The monographs written by Tsypkin (1968 and 1970) contributed to the general comprehension and acceptance of his point of view. Subsequently, adaptive systems became the main topic of Tsypkin’s Laboratory. Also, the theory of optimal and robust identification and stochastic optimization algorithms appeared as other important branches. (Such algorithms must work under uncertain probabilistic characteristics.)

Finally, in 1989, there was another turn in Tsypkin’s research area. He paid much attention to the general control problem under uncertainty when the object’s description is incompletely known. Here, the robust stability of a characteristic polynomial is a typical problem. Tsypkin used frequency methods and derived a very effective graphical criterion (“the Tsypkin—Polyak hodograph”). Furthermore, he proposed a “robustification” program for the whole linear control theory and achieved significant results on this pathway.

Besides the main research areas mentioned above, Tsypkin was concerned with many other problems: from the degree of stability of linear systems to neural networks. At the same time, he felt the unity of the whole control theory and placed frequency methods for linear systems and the resulting graphical criteria, such as the Nyquist and Mikhailov hodographs, in the center. Tsypkin appreciated less the apparatus with state-space descriptions of systems and optimal control based on Pontryagin’s maximum principle. He had an extraordinary capacity for work, working always and everywhere: in his office, at meetings, at home, and at leisure. He wrote 12 books, over 300 scientific papers, and numerous brochures, prefaces, book reviews, and encyclopedic articles.

Tsypkin is widely known in Russia and abroad. He was elected Full Member of the USSR Academy of Sciences (later, the Russian Academy of Sciences), Chairman of the National Committee on Automatic Control, and a member of editorial boards of several peer-reviewed journals. Tsypkin was awarded the Lenin Prize and the Andronov Prize. He presented many papers at leading international congresses and conferences. For example, he participated in all congresses of the International Federation of Automatic Control (IFAC), starting from the first one. Tsypkin was awarded the prestigious Giorgio Quazza Medal (IFAC) and the Rufus Oldenburger Medal of the American Society of Mechanical Engineers as well as received the Sir Harold Hartley Award from the Institute of Measurement and Control (UK). After his death, major international journals on systems engineering and control published special issues dedicated to his memory or obituaries.

Tsypkin had many followers and students, including doctors of sciences and academicians from various CIS countries. Well-known foreign researchers (for example, L. Ljung (Sweden) and P. Kokotovic (Yugoslavia)) consider him as their teacher. Laboratory No. 7 of ICS RAS, organized and headed by Tsypkin for many years, now bears his name. This Laboratory is a leading one in the Institute.

His main books are as follows:

  1. Informatsionnaya teoriya identifikatsii (The Information Theory of Identification), Moscow: Nauka, 1995. — 336 p.;
  2. Relay Control Systems, Cambridge University Press, 1985. — 544 p.;
  3. Osnovy informatsionnoi teorii identifikatsii (Foundations of the Information Theory of Identification), 2nd. ed., Moscow: Nauka, 1984. — 320 p.;
  4. Releinye avtomaticheskie sistemy (Relay Automatic Systems), Moscow: Nauka, 1974. — 576 p.;
  5. Foundations of the Theory of Learning Systems, Mathematics in Science and Engineering, vol. 101, Academic Press, 1973. — 205 p.;
  6. Optimizatsiya. Issledovanie operatsii. Bionika (Optimization. Operations Research. Bionics), Moscow: Nauka, 1973. — 272 p.;
  7. Teoriya nelineinykh impul’snykh sistem (Theory of Nonlinear Impulse Systems), Moscow: Nauka, 1973. — 416 p. (coauthor Yu.S. Popkov);
  8. Metody optimizatsii avtomaticheskikh sistem (Optimization Methods of Automatic Systems), Moscow: Energiya, 1972. — 368 p.;
  9. Adaptation and Learning in Automatic Systems, Mathematics in Science and Engineering, vol. 73, Academic Press, 1971. — 291 p.;
  10. Osnovy teorii obuchayushchikhsya sistem (Foundations of the Theory of Learned Systems), Moscow: Nauka, 1970. — 252 p.;
  11. Adaptatsiya i obuchenie v avtomaticheskikh sistemakh (Adaptation and Learning in Automatic Systems), Moscow: Nauka, 1968. — 400 p.;
  12. Sampling Systems Theory and Its Application, International Series of Monographs on Electronics and Instrumentation, Pergamon, 1964. — 374 p.;
  13. Perekhodnye i ustanovivshiesya protsessy v impul’snykh tsepyakh (Transient and Steady-State Processes in Impulse Circuits), Moscow: Gosenergoizdat, 1951. — 221 p.;
  14. Kriterii ustoichivosti lineinykh sistem avtomaticheskogo regulirovaniya (Stability Criteria for Linear Automatic Control Systems), Moscow: Mashgiz, 1950. — 512 p.

Many books are presented in the Institute’s database:

The list of journal papers by Tsypkin is available from Math-Net.Ru:

His papers in Avtomatika i Telemekhanika can be found at:

For their English versions, see the microfilm collection of Automation and Remote Control:

In addition, browse Tsypkin’s publications at:

Articles and books about Ya.Z. Tsypkin

1. B. T. Polyak, A. V. Nazin, The 100th Birthday of Yakov Zalmanovich TsypkinAvtomat. i Telemekh., 2019, no. 9, 6—8.
2. Yakov Zalmanovich Tsypkin (1919—1997), edited by B.T. Polyak, Moscow: ICS RAS, 2007. — 304 p. ISBN 978-5-382-00623-9.
3. In Blessed Memory of Yakov Zalmanovich Tsypkin, Avtomat. i Telemekh., 1999, no. 3.
4. E. I. Juri, In Memory of Yakov Zalmanovich Tsypkin. A Life in Feedback ControlAvtomat. i Telemekh., 1999, no. 3, 5—24; Autom. Remote Control60:3 (1999), 300—314.
5. Ya. Z. TsypkinAvtomat. i Telemekh., 1998, no. 2, 185—186.

Also, see the Wikipedia page devoted to Tsypkin:

Scopus Author ID: 7006475689