Comparison of Sliding Mode and Petri Nets Control for Multicellular Chopper

International audienceIn this paper a new class of power converters, serial multicellular chopper, will be studied. After recalling the dynamical equations of the converter, its hybrid dynamical behavior and properties are highlighted. This hybrid system induces new and difficult control problems. Then, two control strategies are proposed. The first is a sliding mode control and the second is a Petri Nets control. Some simulations are carried out to prove the efficiency and the robustness of the two controls for the case of a two cells converter connected to a nonlinear load. The comparison between sliding mode control and Petri nets control is carried out. Simulation results are provided to verify the conclusions

Lyapunov-based HOSM control

[EN] We give an overview of the methods of analysis and design of High-Order Sliding Mode Controllers (HOSM) and observers,  including also those taking advantage of a discontinuous integral action. First, discontinuous state feedback controllers enforcing a sliding mode of arbitrary order are described. Then a recent class of HOSM  controllers is presented, which consists of a continuousstate feedback controller and a discontinuous integral term. High-order sliding mode observers are also introduced,  which are able to estimate robustly and in finite time the states of the uncertain plant, and they allow the implementation of an output feedback control law. All described designs are based in explicit Lyapunov functions, what is a main contribution of the research group of the authors at the Universidad Nacional Aut´onoma de M´exico, in Mexico City. The paper is tutorial and only the basic  results are presented, leaving aside the rigorous mathematical formulation and proof. For this the appropriate literature is referred to. The results are illustrated using simulations and an experimental validation in a laboratory set up of a magnetic levitation system.[ES] En este trabajo se presenta una panorámica del desarrollo de los métodos básicos de análisis y diseño de controladores y observadores por modos deslizantes de orden superior. Inicialmente se describen los controladores por retroalimentación de estados con una ley de control discontinua, que generan un modo deslizante de cualquier orden. Posteriormente se presenta una nueva clase de algoritmos por modos deslizantes de orden superior, que consisten en una retroalimentación de estados continua y una acción de control integral discontinua. Se describen también observadores por modos deslizantes, que estiman los estados del sistema en tiempo finito, y que permiten obtener un controlador por retroalimentación de la salida. Todos los diseños presentados se basan en el uso de funciones de Lyapunov (explícitas), que constituyen una contribución importante del grupo de trabajo de los autores en la Universidad Nacional Autónoma de México. La presentación es tutorial y solo se dan los resultados, dejando a un lado la formalización rigurosa y las pruebas matemáticas. Para ello se refiere al lector a la literatura pertinente. Se ilustran los resultados mediante simulaciones y la validación experimental en un sistema de levitación magnética.PAPIIT-UNAM, proyecto IN102121Moreno, JA.; Fridman, L. (2022). Control por modos deslizantes de orden superior basado en funciones de Lyapunov. Revista Iberoamericana de Automática e Informática industrial. 19(4):394-406. https://doi.org/10.4995/riai.2022.17013OJS39440619

Dynamic involvement of real world objects in the IoT: a consensus-based cooperation approach

A significant role in the Internet of Things (IoT) will be taken by mobile and low-cost unstable devices, which autonomously self-organize and introduce highly dynamic and heterogeneous scenarios for the deployment of distributed applications. This entails the devices to cooperate to dynamically find the suitable combination of their involvement so as to improve the system reliability while following the changes in their status. Focusing on the above scenario, we propose a distributed algorithm for resources allocation that is run by devices that can perform the same task required by the applications, allowing for a flexible and dynamic binding of the requested services with the physical IoT devices. It is based on a consensus approach, which maximizes the lifetime of groups of nodes involved and ensures the fulfillment of the requested Quality of Information (QoI) requirements. Experiments have been conducted with real devices, showing an improvement of device lifetime of more than 20%, with respect to a uniform distribution of tasks

Robust Course Keeping Control of a Fully Submerged Hydrofoil Vessel without Velocity Measurement: An Iterative Learning Approach

This paper proposes a novel robust output feedback control methodology for the course keeping control of a fully submerged hydrofoil vessel. Based on a sampled-data iterative learning strategy, an iterative learning observer is established for the estimation of system states and the generalized disturbances. With the state observer, a feedback linearized iterative sliding mode controller is designed for the stabilization of the lateral dynamics of the fully submerged hydrofoil vessel. The stability of the overall closed-loop system is analyzed based on Lyapunov stability theory. Comparative simulation results verify the effectiveness of the proposed control scheme and show the dominance of the disturbance rejection performance

Nonlinear L

The L2-gain analysis is extended towards hybrid mechanical systems, operating under unilateral constraints and admitting both sliding modes and collision phenomena. Sufficient conditions for such a system to be internally asymptotically stable and to possess L2-gain less than an a priori given disturbance attenuation level are derived in terms of two independent inequalities which are imposed on continuous-time dynamics and on discrete disturbance factor that occurs at the collision time instants. The former inequality may be viewed as the Hamilton-Jacobi inequality for discontinuous vector fields, and it is separately specified beyond and along sliding modes, which occur in the system between collisions. Thus interpreted, the former inequality should impose the desired integral input-to-state stability (iISS) property on the Filippov dynamics between collisions whereas the latter inequality is invoked to ensure that the impact dynamics (when the state trajectory hits the unilateral constraint) are input-to-state stable (ISS). These inequalities, being coupled together, form the constructive procedure, effectiveness of which is supported by the numerical study made for an impacting double integrator, driven by a sliding mode controller. Desired disturbance attenuation level is shown to satisfactorily be achieved under external disturbances during the collision-free phase and in the presence of uncertainties in the transition phase

Robust Course Keeping Control of a Fully Submerged Hydrofoil Vessel with Actuator Dynamics: A Singular Perturbation Approach

This paper presents a two-time scale control structure for the course keeping of an advanced marine surface vehicle, namely, the fully submerged hydrofoil vessel. The mathematical model of course keeping control for the fully submerged hydrofoil vessel is firstly analyzed. The dynamics of the hydrofoil servo system is considered during control design. A two-time scale model is established so that the controllers of the fast and slow subsystems can be designed separately. A robust integral of the sign of the error (RISE) feedback control is proposed for the slow varying system and a disturbance observer based state feedback control is established for the fast varying system, which guarantees the disturbance rejection performance for the two-time scale systems. Asymptotic stability is achieved for the overall closed-loop system based on Lyapunov stability theory. Simulation results show the effectiveness and robustness of the proposed methodology

Eye quietness and quiet eye in expert and novice golf performance: an electrooculographic analysis

Quiet eye (QE) is the final ocular fixation on the target of an action (e.g., the ball in golf putting). Camerabased eye-tracking studies have consistently found longer QE durations in experts than novices; however, mechanisms underlying QE are not known. To offer a new perspective we examined the feasibility of measuring the QE using electrooculography (EOG) and developed an index to assess ocular activity across time: eye quietness (EQ). Ten expert and ten novice golfers putted 60 balls to a 2.4 m distant hole. Horizontal EOG (2ms resolution) was recorded from two electrodes placed on the outer sides of the eyes. QE duration was measured using a EOG voltage threshold and comprised the sum of the pre-movement and post-movement initiation components. EQ was computed as the standard deviation of the EOG in 0.5 s bins from –4 to +2 s, relative to backswing initiation: lower values indicate less movement of the eyes, hence greater quietness. Finally, we measured club-ball address and swing durations. T-tests showed that total QE did not differ between groups (p = .31); however, experts had marginally shorter pre-movement QE (p = .08) and longer post-movement QE (p < .001) than novices. A group × time ANOVA revealed that experts had less EQ before backswing initiation and greater EQ after backswing initiation (p = .002). QE durations were inversely correlated with EQ from –1.5 to 1 s (rs = –.48 - –.90, ps = .03 - .001). Experts had longer swing durations than novices (p = .01) and, importantly, swing durations correlated positively with post-movement QE (r = .52, p = .02) and negatively with EQ from 0.5 to 1s (r = –.63, p = .003). This study demonstrates the feasibility of measuring ocular activity using EOG and validates EQ as an index of ocular activity. Its findings challenge the dominant perspective on QE and provide new evidence that expert-novice differences in ocular activity may reflect differences in the kinematics of how experts and novices execute skills