The 14th Data-Driven Control and Learning Systems Conference (DDCLS 2025) was held in Wuxi from May 9 to 11. The research finding "Distribution and Application of Roots of Neutral Quasi-Polynomials" jointly obtained by Associate Professor Wang Honghai from the School of Information and Professor Han Qinglong from Swinburne University of Technology in Australia was presented by Professor Han Qinglong in the Keynote Address, which was one of the three keynote reports of this conference.
As mentioned in the report, "the distribution of roots of quasi-polynomials" is a transformed form of "the distribution of characteristic roots of time-delay systems", and it is the theoretical basis for the analysis and control of time-delay systems. It is a highly challenging basic scientific research issue in the field of control.
For many years, Wang has been deeply engaged in the research of analysis and control of time-delay systems, especially in the study of the distribution of roots of quasi-polynomials. He has continuously proposed innovative theoretical results, which have had a significant impact on the theoretical research of control systems. Since 2013, Wang has been deeply researching for ten years on the issue of how to establish the distribution results of roots of similar Pontryagin's quasi-polynomials with feasibility, achieving a major breakthrough. In 2023, he completed the derivation of the main conclusion. Wang and Han have collaborated to publish a series of papers on top-notched journals in the field of control from the proposal to the solution of the root distribution problem of quasi-polynomials. The most important research result among them, "The Distribution of Roots of Neutral quasi-polynomials and Its Applications", was published in the form of two serials (Part I and Part II) in the authoritative international control journal IEEE Transactions on Automatic Control (referred to as "IEEE TAC"). This is the first time that the theoretical research achievements of our teachers have been serialized and published in this journal.
In the paper, a determinable frequency boundary for the distribution analysis of the roots of quasi-polynomials was established. On this basis, the distribution quantity criterion of the roots of neutral complex coefficient quasi-polynomials in the right semi-open plane of the complex plane and the Hurwitz stability criterion were proposed, and they are feasible in application. This research finding will also provide new research ideas and effective mathematical tools for the analysis and control design of systems such as time-delay systems, discrete systems, and sampling systems.
At the Australia-New Zealand Control Conference (ANZCC 2025) held in the Gold Coast of Australia from January 30 to 31, 2025, this research finding was also invited to be presented as a conference report (one of the two conference reports of this conference).
It is reported that Wang has long been dedicated to the research on the analysis and control design of complex control systems. He has achieved significant academic and scientific research results in the characteristic root distribution of time-delay control systems and the design of controllers based on pole assignment. He has published over 30 papers related to the analysis of time-delay systems and controller design in international high-level academic journals and conferences. As the first author and corresponding author, seven research papers related to the characteristic root distribution analysis and control design of time-delay systems have been published on IEEE Transactions on Automatic Control and Automatica, the top international authoritative journals in the field of control.
