Analysis and control of nonlinear feedback systems by differential positivity and dominance theory

Lead Research Organisation: University of Cambridge
Department Name: Engineering

Abstract

The PhD project is rooted in Control engineering. The project will develop methods for analysis and control of nonlinear feedback systems, which are ubiquitous in natural and engineered systems.

The project is based on differential analysis and takes advantage of the novel theories of differential positivity and dominance. The aim of the project is to develop new tools for analysis and control design of systems which exhibit richly non-linear behaviour (e.g. bifurcations, discontinuities and oscillations) and are found throughout engineering, the physical sciences, the life sciences and the economic and social sciences.
Novel algorithms will be developed within the project to foster the use of differential positivity and dominance theory on several applications of interests, which include robotics, transportation, biological processes, and analysis and design of large-scale distributed systems.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509620/1 01/10/2016 30/09/2022
1950140 Studentship EP/N509620/1 01/10/2017 30/09/2021 Dimitris Kousoulidis
 
Description We developed computational tools to support the research on monotone systems and differential positivity (a system analysis and synthesis framework recently developed in Cambridge). Monotonicity and differential positivity allow us to study systems with rich non-linear behaviour (e.g. bifurcations, discontinuities and oscillations) that are found throughout engineering, the physical sciences, the life sciences, and the economic and social sciences. Differential positivity provides a novel general framework that can be used for studying and reasoning about the behaviour of these systems in a unified way.

With the computational tools that we have developed, we can numerically verify when a system is differentially positive and we can use the differential positivty framework in applications. We demonstrated how our numerical tools can be used to analyse and design a range of non-linear systems, including for example, non-linear multi-agent systems and robust switches. Our original objectives have been met, however we continue to work on scaling up this approach to bigger systems and networks of systems for the remainder of the award. Because of the theoretical nature of this research, we expect that the impact will be more on the long-term.

Remarkably, our computational tools for differential positivity can also be adapted to the classical problems of stability and stabilisation of nonlinear systems. This opens new research directions that we will also be exploring in the following months.
Exploitation Route These outcomes will be directly used by the project supervisor and his future students and collaborators. The computational tools developed in this research will be integrated into graduate courses offer in the Department of Engineering at the University of Cambridge.

We are also hoping that our publications and application examples will seed interest in exploring these approaches by various domain experts and that, once it is fully published, our research toolbox software will lower the technical barrier required to do so.
Sectors Electronics,Energy,Environment,Transport

 
Description CDC 2019 Travel Award
Amount € 325 (EUR)
Organisation Institute of Electrical and Electronics Engineers (IEEE) 
Sector Learned Society
Country United States
Start 12/2019 
End 12/2019
 
Title Toolbox for Polyhedral Computation 
Description Toolbox developed in parallel with our research for the duration of this award. It complements our research by providing computational tools for the study of differential positivity and stability. We plan to release this as an open source package by the end of the award's duration. 
Type Of Technology Software 
Year Produced 2021 
Impact Was used to compute the examples in our two peer reviewed publications and for our third submitted paper. 
 
Description 2019 International Workshop on Control Engineering and Synthetic Biology 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Workshop attended by some of the world leading experts in the intersection of Synthetic Biology and Control theory.
Got the opportunity to better understand the tools and methods currently used in the field and how our research can be used to improve them and networked with other postgraduate students.
Year(s) Of Engagement Activity 2019
URL http://sysos.eng.ox.ac.uk/wiki/index.php/SynBioControl2019
 
Description 58th Conference on Decision and Control 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Presented our paper in the biggest conference in our field that has both a big academic and industry presence.
We got the opportunity to formally present our work and received very good engangement from the audience of our session.
We also got the chance to network with our peers and learn more about the latest developments in our field.
Year(s) Of Engagement Activity 2019
URL https://cdc2019.ieeecss.org/
 
Description Emmanuel College Graduate Symposium 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact One day event organized by Emmanuel College's Middle Combination Room (MCR) that brought together all graduate students of the college, with fields ranging from History to Astrophysics and was also attended by senior members of the college. Presented our work and the more general problems that our field attempts to solve in an approachable way.
Year(s) Of Engagement Activity 2019
 
Description IFAC World Congress 2020 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Was turned to a virtual conference because of COVID-19.
Created video presentation showcasing our work and was able to view many interesting talks by experts in the field.
Unfortunately, the virtual layout limited opportunities for networking.
Year(s) Of Engagement Activity 2020
URL https://www.ifac2020.org/
 
Description Personal Website 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Personal academic website showcasing our work on this award and providing some high-level context of our plans; recorded around 200 unique visitors.
Year(s) Of Engagement Activity 2020,2021
URL https://dkous.com/