2025Activity reportProject-TeamVALSE
RNSR: 201923115X- Research center Inria Centre at the University of Lille
- In partnership with:Ecole Centrale de Lille, Université de Lille
- Team name: Finite-time control and estimation for distributed systems
- In collaboration with:Centre de Recherche en Informatique, Signal et Automatique de Lille
Creation of the Project-Team: 2019 November 01
Each year, Inria research teams publish an Activity Report presenting their work and results over the reporting period. These reports follow a common structure, with some optional sections depending on the specific team. They typically begin by outlining the overall objectives and research programme, including the main research themes, goals, and methodological approaches. They also describe the application domains targeted by the team, highlighting the scientific or societal contexts in which their work is situated.
The reports then present the highlights of the year, covering major scientific achievements, software developments, or teaching contributions. When relevant, they include sections on software, platforms, and open data, detailing the tools developed and how they are shared. A substantial part is dedicated to new results, where scientific contributions are described in detail, often with subsections specifying participants and associated keywords.
Finally, the Activity Report addresses funding, contracts, partnerships, and collaborations at various levels, from industrial agreements to international cooperations. It also covers dissemination and teaching activities, such as participation in scientific events, outreach, and supervision. The document concludes with a presentation of scientific production, including major publications and those produced during the year.
Keywords
Computer Science and Digital Science
- A5.9.2. Estimation, modeling
- A6.4.1. Deterministic control
- A6.4.4. Stability and Stabilization
- A6.4.5. Control of distributed parameter systems
- A9.5. Robotics and AI
Other Research Topics and Application Domains
- B1.1.8. Mathematical biology
- B2.1. Well being
- B5.6. Robotic systems
- B7.2.1. Smart vehicles
1 Team members, visitors, external collaborators
Research Scientists
- Denis Efimov [Team leader, INRIA, Senior Researcher, HDR]
- Andrey Polyakov [INRIA, Researcher, HDR]
- Rosane Ushirobira [INRIA, Senior Researcher, from Oct 2025, HDR]
- Rosane Ushirobira [INRIA, Researcher, until Sep 2025, HDR]
Faculty Member
- Laurent Bako [CENTRALE LILLE, Professor, from Sep 2025]
Post-Doctoral Fellows
- Ajul Dinesh [INRIA, Post-Doctoral Fellow]
- Marcel Fang [INRIA, Post-Doctoral Fellow, from May 2025]
- Radoslaw Patelski [INRIA, Post-Doctoral Fellow]
PhD Students
- Isaac Ambit Brao [INRIA]
- Mohamed Yassine Arkhis [INRIA]
- Mericel Ayamou [UNIV LILLE, until Nov 2025]
- Mahugnon Dadjo [INRAE, until Aug 2025]
- Min Li [CSC Scholarship, until Oct 2025]
- Danilo Rodrigues De Lima [INRIA]
Interns and Apprentices
- Mathias Dubuisson [INRIA, Intern, from May 2025 until Aug 2025]
Administrative Assistants
- Isabelle Aslani [INRIA, from Feb 2025 until May 2025]
- Lucile Leclerq [INRIA, until Jan 2025]
- Karine Lewandowski [INRIA, from Jun 2025]
Visiting Scientists
- Andres Gonzalez Rodriguez [UNAM, from Nov 2025]
- Manuel Mera [ESIME - IPN, Mexico, from Nov 2025 until Nov 2025]
- Héctor Ríos [I.T. La Laguna, Mexico, from Jun 2025 until Jun 2025]
External Collaborator
- Gerald Dherbomez [CNRS]
2 Overall objectives
The VALSE team studies estimation and control problems arising in the analysis and the design of distributed, uncertain, and interconnected dynamical systems:
- Using the concepts of finite-time/fixed-time/hyperexponential convergence and stability, the main idea is to separate and hierarchize in time the control and estimation processes, which are distributed in space. These approaches greatly simplify their analysis and the design of large-scale solutions.
- The main areas of investigation and application for the team are the Internet of Things (IoT) and Cyber-Physical Systems (CPS).
- The team aims to draw up algorithms for decentralized finite-time control and estimation. The methodology to be developed includes extensions of the theory of homogeneous systems and finite-time/fixed-time/hyper-exponential convergence and stability notions. Particular attention is given to applications in real-world scenarios.
- It is a joint proposal with the CNRS CRIStAL UMR 9189.
3 Research program
The VALSE team works in the domains of control science: dynamical systems, stability analysis, estimation, and automatic control. Our developments are focused on the theoretical and applied aspects related to the control and estimation of large-scale multi-sensor and multi-actuator systems based on the use of the theories of finite-time/fixed-time/hyperexponential convergence and homogeneous systems. The Lyapunov function method and other methods of analysis of dynamical systems form a basis for the studies in the VALSE team.
The key idea of the research program for the team is that a fast (non-asymptotic) convergence of the regulation and estimation errors increases the reliability of intelligent distributed actuators and sensors in complex scenarios, such as interconnected cyber-physical systems (CPS).
The expertise of VALSE's members in theoretical developments of control and estimation theory (finite-time control and estimation algorithms in centralized context 74, 60, 71, 70, 67, homogeneity framework for differential equations 75, 62, 61, 63, 65, 76, 72, time-delay systems 64, 66, 79, distributed systems 73 and algebraic-based methods for estimation 77, 78) is an essential ingredient to achieve our objective.
The generic chart of goals and tasks included in the scientific work program of VALSE and the interrelations between them are presented in Fig. 1. We have selected three main objectives to pursue with the related tasks to fulfill:
- The first objective is to design control and estimation solutions for CPS and IoT, which is the principal aim of VALSE. It will contain the main outcomes of our research.
- The second objective is more theoretical and needed to make the basement for our design and analysis parts in the last goal.
- The third objective deals with applications that will drive the team and motivate the theoretical studies and selected design performances.
All these objectives are interconnected: from a particular problem in an IoT application, it is planned to design control or estimation algorithms, leading to the development of theoretical tools; and vice versa, a new theoretical advance can provide a possibility for the development of novel tools that can be used in applications.
Graphical presentation of objectives given in the text
Structure of the objectives and tasks treated in VALSE
To explain our motivation: why use finite time? Applying any method for control/estimation has a price in terms of its advantages and disadvantages. There is no universal framework that is the best always and everywhere. Finite-time may appear as a luxurious property for a physical system, requiring nonlinear tools. Of course, if an asymptotic convergence and a linear model are enough for solving a given problem, then there is no reason to develop something else. However, most of the present problems in CPS and IoT are nonlinear (i.e., they have various local behaviors that cannot be collected in only one linear model). Design and analysis of various local linearized models and solutions are luxurious, too. The theory of homogeneity can go beyond linearity, offering many new features while not appearing as severe as other nonlinear tools and having almost all hints of the linear framework. Suppose that, thanks to the homogeneity theory, finite-time/fixed-time can be obtained with little difficulty while adding the bonuses of stronger robustness and faster convergence compared to the linear case? We are convinced that the price of going beyond linear control and estimation can be strongly dropped by maturing the theory of homogeneity and finite/fixed-time convergence. We are also convinced that it will be compensated in terms of robustness and speed, which can be demanded in the new areas of application such as IoT for example.
4 Application domains
One of the objectives of the team is to apply the developed control and estimation algorithms for different scenarios in IoT or CPS. Participation in various potential applications allows the VALSE team to better understand the features of CPS and their required performances and to properly formulate the control and estimation problems that must be solved. Here is a list of ongoing, past, and potential applications addressed by the team:
- smart bivalve-based biosensor for water quality monitoring (ANR project
WaQMoS, the developed
sensor is shown in Fig. 2): in living beings,
the presence of persistent external perturbations may be difficult
to measure, and important model uncertainties render the application
of conventional techniques complicated; another issue for estimation
is the consensus-seeking between animals for contamination detection 58;
Underwater photo of bivalves connected to computer
Figure 2: The valvometer used in the ANR project WaQMoS
- control and estimation for flying vehicles, e.g. quadrotors
or blimps given in Fig. 3: the nonlinearity of the model and its
uncertainty coupled with important aerodynamic perturbations have
to be compensated by fast (finite- or fixed-time) and robust control
and estimation algorithms;
1) Photo of blimp robot, big ball with helium with a small computer at the bottom. 2) S. Wang placing a bottle of water on the flying drone
1) Photo of blimp robot, big ball with helium with a small computer at the bottom. 2) S. Wang placing a bottle of water on the flying drone
Figure 3: Blimp and quadrotor robots
- human behavior modeling and identification with the posterior design of algorithms for human-computer interaction (HCI, with the Inria team LOKI): robust finite-time differentiators demonstrate good estimation capabilities needed for prediction in this application 78, 59;
- human physiological characteristics estimation (like emotion detection, galvanic skin response filtering, fatigue evaluation in collaborations with Neotrope and Ellcie Healthy): intelligent robust filtering and finite-time distributed estimation are key features in these scenarios;
- path planning for autonomous vehicles taking into account the behavior of humans (with the Inria team SCOOL): application of interval and finite-time adaptive estimation and prediction techniques allows for treating the uncertainty of the environment by reducing the computational complexity of reinforcement learning 691;
- flow control 68: the case of control and
estimation of a distributed-parameter system with very fast and uncertain
dynamics, where finite-time solutions developed by VALSE are necessary (an example of results is given in Fig. 4);
Different graphics demonstrating flow behavior and the control input
Figure 4: Particle Image Velocimetry on flow control for an Ahmed body (LAMIH wind tunnel)
- control of bioreactors (in the framework of IPL COSY): here again, the problem is an important uncertainty of the model, which can be handled by robust sliding mode control algorithms, or by applying adaptive finite-time estimation and identification tools;
It is worth highlighting a widespread distribution of various scientific domains in the list of applications for the team given above. Such interdisciplinarity for VALSE is unsurprising since control theory is a science of systems whose interest today is, by nature, to interface with other disciplines and their fields of application. This is also well aligned with the domain of CPS, which by its origin requires multidisciplinary competencies.
5 Social and environmental responsibility
Activities of the team related to social responsibility:
- Engaging in outreach programs to promote mathematics education and awareness in local communities: Rosane Ushirobira participated in the work of CIMPA
- Collaborating with educational institutions to support the development of math skills for the young generation: Rosane Ushirobira made several CHICHE sessions in high schools of Lille and in the metropolitan area
- Participating in mentorship programs to encourage underrepresented groups to pursue careers in mathematics and related fields: Rosane Ushirobira participated in the days of young girls in informatics and mathematics (RJMI Inria Lille 2025)
- Contributing to interdisciplinary research that addresses societal challenges, such as healthcare, by applying mathematical modeling and analysis: the ANR project NOCIME has VALSE participation in the analysis of mathematical epidemiological models. In addition, there are publications on this subject.
- Mentoring and supporting early-career researchers to foster a diverse and inclusive research community
Activities of the team related to environmental responsibility:
- Developing mathematical models and the methods for their design and analysis to support sustainable energy systems: the ANR-DFG project SyNNum is devoted to this issue
- Collaborating with environmental scientists, engineers, and policymakers to provide mathematical insights and solutions for environmental challenges and their mitigations: a Ph.D. student was supervised by INRAE and VALSE on the wastewater treatment problems
Overall, social and environmental responsibility for researchers in the team involves using mathematical expertise to address societal issues, promote inclusivity, and contribute to environmental sustainability through research, collaboration, and outreach efforts.
6 Highlights of the year
- Laurent Bako has joined the team after being recruited as a Professor at Ecole Centrale de Lille
- Rosane Ushirobira got the promotion to the Senior Researcher grade
- 28 journal publications, among them 3 in IEEE Transaction on Control and 5 in Automatica, which are the top revues in the domain of the theory of control (28 of the total production)
- Two volumes handbook was published 46, 47
7 Latest software developments, platforms, open data
7.1 Latest software developments
7.1.1 HCS Toolbox
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Name:
Homogeneous Systems Control Toolbox (HSC Toolbox) for MATLAB
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Keywords:
Control design, Matlab, Homogeneity
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Functional Description:
Homogeneous Systems Control Toolbox (HCS Toolbox) for MATLAB is a collection of functions for design and tuning of control systems with improved control quality (faster convergences, better robustness, smaller overshoots, etc) based on the concept of a dilation symmetry (homogeneity). Homogeneous controllers/observers design well as procedures for upgrading of existing linear controllers/observers to nonlinear (homogeneous) ones are developed for both Single-Input Single-Output (SISO) and Multiply-Input Multiply-Output (MIMO) systems.
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Release Contributions:
HCS Toolbox for MATLAB ver. 0.2
This is the first release of HCS Toolbox for MATLAB. The list of MATLAB functions provided for homogeneous control systems design:
(Homogeneous Euclidean Space) hnorm - canonical homogeneous norm (bisection method) hphi - homogeneous transformation of Rn̂ hphi_inv - inverse homogeneous transformation of Rn̂ hadd - sum of vecotors in homogeneous Euclidian space hdot - product by scalar in homogeneous Euclidiean space hinner - inner product in homogeneous Euclidean space (Homogeneous Geometric Objects) hproj - computation of homogeneous projection hcurve - generation of points on a homogeneous curve hsphere - generation of points on a homogeneous sphere hcone - generation of points on a unit sphere belonging to linear homogeneous cone (Approximation of Canonical Homogeneous Norm) hnorm_r - explicit homogeneous "norm" for iagonizable dilation hnorm_newton - canonical homogeneous norm by Newton method hnorm_ANN - canonical homogeneous norm by ANN approx_hnorm_ANN - approximation of canonical homogeneous norm by ANN approx_hnorm_r - approximation of canonical homogeneous norm for diagonalizable dilation (needs YALMIP) (Homogeneous Control) hpc_design - Homogeneous Proportional Control (HPC) design chpc_design - constant-time HPC design hpci_design - Homogeneous Proportional-Integral Control (HPIC) design hsmc_design - Homogeneous Sliding Mode Controller (HSMC) design hsmci_design - design of HSMC with Integral action (HSMCI) fhpc_design - fixed-time HPC design fhpic_design - fixed-time HPIC design lpc2hpc - upgrading Linear Proportional Control (LPC) to HPC lpic2hpc - upgrading Linear PI control (LPIC) to HPIC (Discretization of Homogeneous Control) e_hpc - explicit discretization of HPC si_hpc - semi-implicit discretization of HPC c_hpc - consistent discretization of HPC e_hpic - explicit discretization of HPIC e_hsmc - explicit discretization of HSMC si_hsmc - semi-implicit explicit discretization of HSMC e_hsmci - explicit discretization of HSMC with Integral action e_fhpc - explicit discretization of fixed-time HPC si_fhpc - semi-implicit discretization of Fixed-time HPC e_fhpic - explicit discretization of fixed-time HPIC (Homogeneous State Estimation) ho_design - Homogeneous Observer (HO) design fho_design - fixed-time HO design lo2ho - upgrading Linear Observer (LO) to HO (Discretization of Homogeneous Observer) e_ho - explicit discretization of HO e_fho - explicit discretization of FHO si_ho - semi-implicit discretization of HO si_fho - semi-implicit discretization of FHO (Block Controlability/Observability Forms) block_con - transformation to block controlability form bloc_obs - transformation to block bservability form trans_con - transformation to partial block controlability form trans_con - transformation to partial block observability form output_form - transformation to reduced order output control system (Examples) demo_hnorm - example of canonical (implicit) homogeneous norm demo_halgebra - example of homogeneous Euclidean space demo_hsphere - example of homogeneous balls in 2D demo_hcurve - example of homogeneous curve in 2D demo_hcone - example of homogeneous cone in 2D demo_hpc - example of HPC design and simulation demo_c_hpc - example of constant-time HPC design and simulation demo_hpic - example of HPIC design and simulation demo_hsmc - example of HSMC design and simulation demo_hsmci - example of HSMCI design and simulation demo_fhpc - example of fixed-time HPC design and simulation demo_fhpic - example of fixed-time HPIC design and simulation demo_lpc2hpc - example of upgrading LPC to HPC/FHPC demo_lpic2hpic - example of upgrading LPIC to HPIC/FHPIC demo_ho - example of HO design and simulation demo_fho - example of fixed-time HO design and simulation demo_lo2ho - example of upgrading LO to HO demo_block_con - example of block controllability form demo_block_obs - example of block observability form
For more details please read the documentation: http://researchers.lille.inria.fr/p̃olyakov/hcs/tutorial.html
- URL:
-
Contact:
Andrey Polyakov
8 New results
8.1 Analysis and design of homogeneous and finite-time stable systems
Participants: Denis Efimov, Andrey Polyakov.
The paper 14 addresses the problem of transforming a locally asymptotically stabilizing time-varying control law to a global one with accelerated finite/fixed-time convergence rates. The proposed approach relies on an extension of the theory of homogeneous systems to homogeneity only with respect to a part of the state variables and on the associated partial stability properties. The proposed control design uses the implicit Lyapunov function framework.
The paper 1 studies robust stability properties in presence of external perturbations for previously introduced partially homogeneous dynamical systems (for which the dilation is applied only to a part of the state variables). The results can be utilized to construct time-dependent control laws for nonholonomic systems which not only provide accelerated convergence (finite-time or nearly fixed-time) but also guarantee robustness to unmeasured disturbances. Examples of input-to-output stabilization of a nonholonomic integrator are reported.
The paper 18 presents a novel delayed high-order sliding mode control strategy supported by dedicated mathematical tools. Building on the implicit Lyapunov-Razumikhin function method for establishing accelerated (hyperexponential) stability in time-delay systems and the design of high-order sliding mode controls for chain of integrators, we propose a time-delay modification/approximation of a sliding mode feedback, preserving the key advantages of this approach, such as the ability to reject matched perturbations and hyperexponential convergence, while significantly reducing chattering. We validate our theoretical findings through numerical simulations, providing empirical support for the effectiveness of the proposed method.
The paper 5 investigates the robust asymptotic stabilization of a linear time-invariant system by static feedback with a static state quantization. It is shown that a controllable linear system can be stabilized to zero in a finite time by means of nonlinear feedback with a quantizer having a limited (finite) number of values (quantization seeds) even when all parameters of the controller and the quantizer are time-invariant. The control design is based on generalized homogeneity. A homogeneous spherical quantizer is introduced. The static homogeneous feedback is shown to be a local (or global) finite-time stabilizer for any controllable linear system (depending on the system matrix). The tuning rules for both the quantizer and the feedback law are obtained in the form of linear matrix inequalities. The closed-loop system is proven to be robust with respect to some bounded matched and vanishing mismatched perturbations. Theoretical results are supported by numerical simulations.
8.2 Analysis and design for systems involving delays
Participants: Denis Efimov, Andrey Polyakov.
For a retarded nonlinear system, the paper 3 proposes a modification of the Lyapunov-Razumikhin method introducing a distributed integral of Lyapunov function for comparison with its current value instead of the maximum over delayed interval. The developed conditions are illustrated on different analysis problems presenting integral Halanay-type inequalities.
The problems of stability and stabilization are addressed for a class of nonlinear mechanical systems with distributed delays in 6. Assuming that potential and kinetic energy functions are homogeneous of different degrees, it is shown that the global asymptotic stability of the zero solution for an auxiliary delay-free nonlinear system implies the local asymptotic stability for the original model with distributed delay. The influence of additional nonlinear and time-varying perturbations is investigated using the averaging techniques. The results are obtained applying the Lyapunov-Krasovskii approach, and next extended via the Lyapunov-Razumikhin method to the case with negligible dissipation. The efficiency of the proposed theory is illustrated by solving the problem of a rigid body stabilization.
The new existence conditions for periodic steady-state solution in time-delay convergent systems are presented in 7. The main advantage of this result is that highly nonlinear (without meaningful linear approximation) dynamics are allowed for analysis. These conditions are developed for Persidskii and Lotka-Volterra time-delay systems. The efficiency of the approach is demonstrated on academic examples of these models.
The paper 9 deals with nonlinear boundary stabilization of a 1D reaction-diffusion equation with input delay. Using the modal decomposition approach, we propose a homogeneous-based predictor feedback for stabilizing the unstable modes. We prove the stability of the closed-loop system via the construction of a suitable Lyapunov functional. We present numerical simulations to support the analytical results and compare our proposed controller to linear predictor feedback regarding closed-loop performance and peaking effect.
8.3 Analysis and control of multistable systems
Participant: Denis Efimov.
The paper 22 develops the input-to-state stability (ISS)-control Leonov function (CLeF) approach. The definitions of practical ISS-and integral ISS-CLeFs are refined, and the proposed methodology for control synthesis is improved to simplify the final control law. Then, it is shown that the existence of practical ISS-and integral ISS-CLeFs is a sufficient condition to guarantee the existence of a controller that endows multistable state periodic systems with the ISS and integral ISS properties, respectively. Furthermore, a methodology for the design of such a controller is provided via the well-known Sontag's universal formula. Besides, an extension of the main result is presented to connect the ISS-CLeF approach with the standard Leonov function method, such that the maximal invariant set of the closed-loop system is compact on a manifold. Finally, the proposed approach is applied to the design of an excitation controller for a synchronous generator, which guarantees global ISS properties for the closed-loop system, unlike the usual local results reported in the literature. The obtained control is also independent of the load angle. The effectiveness of the designed controller is demonstrated in simulations.
The Kuramoto model is essential for studying synchronization. In 2, we present sufficient conditions for global synchronization in networks of heterogeneous Kuramoto oscillators in the absence of homoclinic and heteroclinic cycles. The result is established by constructing a suitable Leonov function candidate for the Kuramoto model, which provides sufficient conditions for almost global synchronization in networks with acyclic and meshed topologies. The synchronization property is accompanied by necessary and sufficient conditions to guarantee the existence of equilibria, which are satisfied if the conditions for synchronization hold. The implications of the main conditions and their relationship with the network topology and parameters are discussed. Finally, the results are illustrated via a numerical example.
8.4 Analysis and design of Persidskii systems
Participants: Denis Efimov, Rosane Ushirobira.
The paper 4 investigates analysis and design problems for a class of parameter-varying generalized Persidskii systems. A model within this class is simultaneously linear in timevarying parameters as in LPV framework, and contains sector nonlinearities of the state, as in Persidskii systems. The conditions for (integral) input-to-state stability and input-output-to-state stability are established. These results are developed using both, parameter-dependent and independent, Lyapunov functions. To formulate these conditions, parameterized matrix inequalities are used, which are reduced to linear ones under additional assumptions concerning the model's dependence on the timevarying parameters. Finally, a new robust nonlinear control design method is also developed. The efficacy of these results is illustrated through a numerical academic example and a more complex model describing the nonlinear dynamics of aircraft longitudinal motion.
The paper 26 introduces two state estimators for a class of Persidskii systems that contain bilinear cross-terms in the state, involving nonlinear functions and unknown input. One observer is local, assuming that the state trajectories are small, while the other is designed to be global, considering that the state takes nonnegative values only. The analysis of the estimation error is based on the input-to-output stability theory and the conditions are formulated using linear matrix inequalities. To illustrate our results, we provide simulations for a model of a chemical exothermic reactor and a consumer-resource interaction model.
8.5 Control of robotic systems
Participants: Denis Efimov, Andrey Polyakov, Rosane Ushirobira.
The paper 17 addresses the problem of stabilizing the position of a mobile robot using its kinematic model of unicycle type. A discontinuous and bounded control law is proposed, which guarantees a global solution to the stabilization problem. The properties of the control strategy are analyzed using Lyapunov methods. Furthermore, an event-triggered implementation of the control law is introduced, and its performance and tuning are evaluated through both simulations and experimental results.
The paper 15 presents a robust sampled controller design for trajectory tracking in unicycle mobile robots subject to state, input, and communication constraints, as well as external disturbances such as wheel slipping. The proposed approach integrates two control strategies: an aperiodic control law based on an event-triggered mechanism and a periodic control law using a constant sampled state-feedback controller. The event-triggered control employs the attractive ellipsoid method and the barrier Lyapunov function to ensure performance within a defined safe set, where state constraints are preserved, and a switching set determines the active control strategy. The periodic sampled control considers the maximum sampling time required to achieve trajectory tracking while minimizing bandwidth usage. This strategy guarantees input-to-state stability of the tracking error dynamics against multiplicative external disturbances. Additionally, a straightforward method using linear matrix inequalities is provided to compute the controller gains. Experimental results validate the effectiveness of the proposed robust control approach.
The problem of hyperexponential stabilization for a mobile robot is addressed in 20 by leveraging its kinematic model with external perturbations. To this end, a robust nonlinear control law is designed, and several state and time transformations are introduced, reformulating the system model to an interconnection of integrators. A novel fixed-time stabilization strategy is developed for an uncertain double-integrator system. The whole closed-loop system's convergence rate is rigorously analyzed, demonstrating hyperexponential behavior. The obtained results are compared with existing analogues in numeric experiments.
8.6 Accelerated parameter estimation
Participants: Denis Efimov, Rosane Ushirobira.
The paper 25 contributes to designing a new parameter identification algorithm for linear regression systems with constant unknown parameters and noisy measurements. The proposed algorithm is based on a new accelerated version of the heavy-ball method, which uses a nonlinear extension of Kreisselmeier's filters. For the noise-free case, the algorithm can identify constant parameters accurately and in finite time, assuming persistence of the regressor's excitation. A local stability analysis is developed using the Lyapunov function approach. The robustness characterizations for the noisy case are provided in terms of input-to-state stability property for the parameter identification error dynamics. Additionally, the paper considers a classic optimization problem, taking into account prior data collection of measurements. A reduced version of the proposed identification algorithm is introduced for this case, ensuring global finite-time stability for the noise-free case and local input-to-state stability for the noisy scenario. The effectiveness of the proposed parameter identification algorithm is depicted with some simulation results.
8.7 Application to the wastewater and irrigation problem
Participants: Denis Efimov, Rosane Ushirobira.
A generic model of fertigation is considered in 12, for which the control variable is the irrigation flow rate. We first characterize conditions for which the dynamical system is viable by allowing maximal biomass production at harvesting time. Then, we consider the problem of minimizing the quantity of water delivered during a season under the viability constraint. We provide a complete optimal feedback synthesis as concatenations of bang and boundary arcs. We show that the optimal strategies can be radically different depending on the initial conditions, leading to distinct ways to avoid water and nitrogen stresses for crops. Moreover, we characterize the possibility of having an infinity of optimal singular trajectories.
In 11, an adaptive observer that can estimate both the state and parameters for a class of nonlinear time-varying systems is proposed, for which the regressor depends on the known input-output signals and all the unmeasured states. The state disturbances and measurements that are corrupted by noise are considered. We use the Lyapunov function method to prove that the estimation error dynamics fulfills the state-independent input-to-output stability property with unknown inputs. These results are motivated and illustrated with a three-dimensional crop irrigation model.
9 Bilateral contracts and grants with industry
9.1 Bilateral contracts with industry
Participants: Denis Efimov, Rosane Ushirobira.
- 52 Hertz is a startup (Brest, France) that develops an underwater communication device for divers. This contract aimed to develop an intelligent filtering algorithm that compensates for voice deformation during underwater vocal communication through the device. The code for the filter was written in Matlab, with further help for its adaptation in Python and C. In 2025, RAPID “Mer-Cure” project was accepted bieng supported by DGA, and in cooperation with IFREMER.
10 Partnerships and cooperations
10.1 Inria Challenges
ImAnAI with Naval Group and IIT Delhi, India (supported by CEFIPRA): Improved Bearings-only Target Motion Analysis Using AI Tools
Participants: Efimov Denis.
10.2 International initiatives
10.2.1 Associate Teams in the framework of an Inria International Lab or in the framework of an Inria International Program
FiCENN with IIT Roorkee and NIT Rourkela, India: Finite-time control and estimation using neural network tools
Participants: Efimov Denis, Ushirobira Rosane.
10.2.2 Participation in other International Programs
ECOS Nord
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Title:
Artificial Intelligence-based Control Approaches for Multiple Mobile Robots
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Partner Institution(s):
- I.T. La Laguna, Mexico
- Date/Duration: 2022–2025
- Additionnal info/keywords:
Participants: Efimov Denis, Polyakov Andrey, Ushirobira Rosane.
PHC Aurora
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Title:
Equivalent nonlinear control methods for digitalization in robotics and autonomous systems
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Partner Institution(s):
- University of Agder, Norway
- Date/Duration: 2023–2025
Participants: Efimov Denis, Ushirobira Rosane.
10.3 International research visitors
10.3.1 Visits of international scientists
Participants: Efimov Denis, Ushirobira Rosane.
Other international visits to the team
Manuel Mera
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Status
researcher
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Institution of origin:
ESIME - IPN
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Country:
Mexico
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Dates:
01/11/2025–30/11/2025
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Mobility program/type of mobility:
Inria invited professor
Héctor Ríos
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Status
researcher
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Institution of origin:
I.T. La Laguna
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Country:
Mexico
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Dates:
01/06/2025–15/06/2025
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Mobility program/type of mobility:
ECOS Nord
Andres Gonzalez Rodriguez
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Status
PhD
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Institution of origin:
UNAM
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Country:
Mexico
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Dates:
01/11/2025–27/12/2025
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Mobility program/type of mobility:
Intenrship
10.4 National initiatives
10.4.1 ANR
- NOCIME (New Observation and Control Issues Motivated by Epidemiology), coordinator Pierre-Alexandre Bliman (Inria, Paris), local coordinator Rosane Ushirobira
- SlimDisc (Multivalued control and observation by sliding modes, in finite and infinite dimensions: discretization), coordinator Franck Plestan (EC Nantes), local coordinator Andrey Polyakov
- SyNNuM (Numerical Methods for Stability and Controller Synthesis in Power Systems with Periodic Dynamics), coordinators Denis Efimov (Inria, France) and Johannes Schiffer (Brandenburg University of Technology Cottbus-Senftenberg, Germany)
11 Dissemination
11.1 Promoting scientific activities
11.1.1 Scientific events: organisation
Member of the organizing committees
- Denis Efimov , IFAC ALCO, Mexico City, Mexico
Reviewer
Members of the team perform numerous reviews for the top journals and the conferences in the domain of the theory of control.
11.1.2 Journal
Member of the editorial boards
- Laurent Bako , Associate editor, IEEE Transactions on Automatic Control
- Denis Efimov , Associate editor, IEEE Transactions on Automatic Control
- Denis Efimov , Associate editor, Automatica
- Rosane Ushirobira , Associate editor, Asian Journal of Control
- Rosane Ushirobira , Associate editor, Trends in Computational and Applied Mathematics (TEMA)
11.1.3 Leadership within the scientific community
- Denis Efimov , Senior member IEEE
- Denis Efimov , Member of IFAC TC 1.2. Adaptive and Learning Systems
- Denis Efimov , Publication vice-chair of IFAC TC 9.2. Systems and Control for Societal Impact
- Denis Efimov , Executive committee member, IEEE CSS Technical Committee on Variable Structure and Sliding Mode Control
- Denis Efimov , Co-chair of European PhD Award on Control for Complex and Heterogeneous Systems
- Andrey Polyakov , Member of IFAC TC 2.3. Nonlinear Control Systems
11.1.4 Research administration
- Rosane Ushirobira , Elected member of the Scientific Board and Evaluation Committee of Inria
- Rosane Ushirobira , Jury member of the CRCN/ISFP Inria Lille
11.2 Teaching - Supervision - Juries - Educational and pedagogical outreach
11.2.1 Juries
Members of the team participate in different selection committees, juries of PhD defenses, and HDR
11.2.2 Educational and pedagogical outreach
- Rosane Ushirobira , Basic courses in Linear algebra and Calculus, 76h, L3, Polytech Lille
11.3 Popularization
11.3.1 Productions (articles, videos, podcasts, serious games, ...)
- Video on the Inria center at Lille and with presentation of Valse team
- Publicity for the launch of Inria Challenge ImAnAI
- Publicity on copperation with INRAE and PhD thesis of Mahugnon Dadjo
- Publicity on the launch of project MER-CURE
- Publicity on the results of the ECOS Nord project
11.3.2 Others science outreach relevant activities
- Rosane Ushirobira , 9 CHICHE sessions
12 Scientific production
12.1 Major publications
- 1 articleRobustness of systems homogeneous with respect to a part of variables.Automatica2025. In press. HALback to text
- 2 articleConditions for Global Synchronization in Networks of Heterogeneous Kuramoto Oscillators.Automatica2025. In press. HALDOIback to text
- 3 articleIntegral version of Lyapunov-Razumikhin conditions.Automatica2025. In press. HALback to text
- 4 articleRobust Stability and Stabilization of Continuous-Time Parameter-Varying Persidskii Systems.IEEE Transactions on Automatic Control2025. In press. HALDOIback to text
- 5 articleRobust Finite-time Stabilization of Linear Systems with Limited State Quantization.Automatica171January 2025, 111967HALDOIback to text
12.2 Publications of the year
International journals
International peer-reviewed conferences
Conferences without proceedings
Scientific books
Scientific book chapters
Doctoral dissertations and habilitation theses
Reports & preprints
12.3 Cited publications
- 58 articleVelocity estimation of valve movement in oysters for water quality surveillance.IFAC-PapersOnLine482015, 333--338back to text
- 59 conferenceFrequency Domain Forecasting Approach for Latency Reduction in Direct Human-Computer Interaction.Proc. 56th IEEE Conference on Decision and Control (CDC)Melbourne2017back to text
- 60 articleRobust finite-time output feedback stabilization of the double integrator.International Journal of Control8832015, 451--460back to text
- 61 articleOn Homogeneity and Its Application in Sliding Mode.Int. J. Franklin Institute35142014, 1866--1901back to text
- 62 articleVerification of ISS, iISS and IOSS properties applying weighted homogeneity.Systems & Control Letters622013, 1159--1167back to text
- 63 articleOn conditions of oscillations and multi-homogeneity.Mathematics of Control, Signals, and Systems2812015, 1--37URL: http://dx.doi.org/10.1007/s00498-015-0157-yback to text
- 64 articleDevelopment of Homogeneity Concept For Time-Delay Systems.SIAM Journal on Optimization and Control5232014, 1403--1808back to text
- 65 articleRealization and Discretization of Asymptotically Stable Homogeneous Systems.IEEE Trans. Automatic Control62112017, 5962--5969back to text
- 66 articleWeighted Homogeneity for Time-Delay Systems: Finite-Time and Independent of Delay Stability.IEEE Trans. Automatic Control6112016, 210--215back to text
- 67 articleBoundary time-varying feedbacks for fixed-time stabilization of constant-parameter reaction-diffusion systems.Automatica1032019, 398--407URL: https://doi.org/10.1016/j.automatica.2019.02.013back to text
- 68 articleSISO model-based control of separated flows: Sliding mode and optimal control approaches.International Journal of Robust and Nonlinear Control27182017, 5008-5027back to text
- 69 conferenceInterval Prediction for Continuous-Time Systems with Parametric Uncertainties.Proc. 58th IEEE Conference on Decision and Control (CDC)Nice2019back to text
- 70 articleFinite-time and Fixed-time Observer Design: Implicit Lyapunov function approach.Automatica8712018, 52-60back to text
- 71 articleOn Homogeneous Finite-Time Control for Linear Evolution Equation in Hilbert Space.IEEE Transactions on Automatic Control2018back to text
- 72 articleConsistent Discretization of Finite-time and Fixed-time Stable Systems.SIAM Journal on Optimization and Control5712019, 78--103back to text
- 73 articleOn Homogeneous Distributed Parameter Systems.IEEE Trans. Automatic Control61112016, 3657--3662back to text
- 74 articleFinite-time and fixed-time stabilization: Implicit Lyapunov function approach.Automatica512015, 332-340back to text
- 75 articleNonlinear feedback design for fixed-time stabilization of linear control systems.IEEE Transactions on Automatic Control57(8)2012, 2106-2110back to text
- 76 articleTime-Varying Parameter Identification Algorithms: Finite and Fixed-Time Convergence.IEEE Transactions on Automatic Control6272017, 3671--3678URL: https://dx.doi.org/10.1109/TAC.2017.2673413back to text
- 77 conferenceEstimating the infection rate of a SIR epidemic model via differential elimination.Proceedings of ECCNaples2019back to text
- 78 conferenceA forecasting algorithm for latency compensation in indirect human-computer interactions.Proceedings of ECCAlborg2016, 1081--1086back to textback to text
- 79 articleA note on delay robustness for homogeneous systems with negative degree.Automatica7952017, 178--184back to text