Mohammadreza Davoodi

Event-triggered fault detection, isolation and control design of linear systems

In this paper, the problem of event-triggered integrated fault detection, isolation and control (E-IFDIC) for discrete-time linear systems is considered. Using a filter to represent, characterize, and specify the E-IFDIC module, a multi-objective formulation of the problem is presented based on the H∞/H_ performance criterion. It is shown that by using an event-triggered technique applied to both the sensor and filter nodes, the amount of data that is sent through the sensor-to-filter and filter-to-actuator channels are dramatically decreased. A set of linear matrix inequality (LMI) feasibility conditions are derived to ensure the solvability of the problem as well as to simultaneously obtain the filter parameters and the event-triggered conditions. A numerical example is also provided to illustrate the effectiveness of our proposed design methodology.

Simultaneous fault detection and control design for an autonomous unmanned underwater vehicle

In this paper, the problem of simultaneous fault detection and control (SFDC) for an autonomous unmanned underwater vehicle (AUV) is considered. An H∞ formulation of the SFDC problem using a dynamic observer is developed. A single module designated as the detector/controller is designed where the detector is a dynamic observer and the controller is a state feedback controller based on the dynamic observer. The detector/controller module produces two signals, namely the detection and the control signals. Sufficient conditions for solvability of the problem are obtained in terms of linear matrix inequality (LMI) feasibility conditions. Simulation results for a Subzero III AUV illustrate the effectiveness of our proposed design methodology.

Event-triggered fault estimation and accommodation design for linear systems

The problem of event-triggered active fault-tolerant control (E-AFTC) of discrete-time linear systems is addressed in this paper by using an integrated design of event-triggered fault/state estimator with a fault-tolerant controller. An event-triggered observer is proposed which can simultaneously provide an estimate of the system states and faults. Through an event-triggered transmission mechanism it is shown that the amount of data sent to the observer module is significantly reduced. Moreover, an observer-based fault-tolerant controller based on fault and state estimates is obtained. A robust H∞ formulation of the problem is given that guarantees stability of the resulting closed-loop system, attenuates the effects of external disturbances and compensates the effects of the fault. Linear matrix inequality (LMI) sufficient conditions are derived to simultaneously obtain the observer and controller parameters and the event-triggered condition. Simulation results for an autonomous remotely operated vehicle (ROV) is given to illustrate the effectiveness of the proposed design methodology.

Observer-based tracking controller design for a class of Lipschitz nonlinear systems

In this paper, the observer-based controller design problem for tracking a constant reference input in Lipschitz nonlinear systems is addressed. To this end, at first, a state feedback controller is proposed and sufficient conditions for solvability of the problem are obtained in terms of linear matrix inequality feasibility conditions. Then, it is shown that for the considered Lipschitz nonlinear system, the separation principle holds and the estimation state variables can be used instead of the state variables. Subsequently, an observer for estimating the states of the system and also an observer-based controller is designed. Simulation results on a flexible link are given to verify the effectiveness of the proposed controller.

Event-triggered simultaneous fault detection and consensus control for linear multi-agent systems

This paper investigates the design and development of event-triggered simultaneous fault detection and consensus control (SFDCC) problem for a network of linear agents. Each agent is equipped with a distributed SFDCC unit that uses the information from the relative measurement sensors and data transmission facilities. It is assumed that the data is transmitted from an agent to its neighbours whenever a specific event condition is satisfied. With the proposed methodology each agent can detect not only its own fault but also the faults occurred in its neighbors and at the same time, all the agents can track the output of a reference model. The parameters of the SFDCC module are designed such that a mixed H∞/H- performance index is satisfied based on sufficient conditions in terms of extended linear matrix inequalities (LMIs). It is shown that by using event-triggered data transmission, the amount of data transmitted from an agent to its neighbors and the actuator updates are reduced. Simulation results are presented for fault detection and control of a group of unmanned underwater vehicles to demonstrate and verify the effectiveness of the proposed methodology.

Stochastic event-triggered particle filtering for state estimation

In this paper, the problem of event-triggered (ET) state estimation is studied for nonlinear non-Gaussian systems. Particle filtering (PF) state estimation approach is developed for systems with stochastic ET measurements to overcome the computational problem in minimum mean square error (MMSE) estimators in which the posterior probability function is non-Gaussian due to ET measurement information. The proposed event triggered particle filtering (ETPF) not only solves the problem of non-Gaussianity but also can handle any functional nonlinearity in the system. It is proved that particles are weighted by the predicted event-triggering (ET) probability density function in the estimator side. The application of the proposed methodology to an interconnected four-tank system is also provided to illustrate and demonstrate the effectiveness of our proposed design methodology.

Event-triggered simultaneous fault detection and tracking control for multi-agent systems

ABSTRACT The main aim of this study is to design distributed simultaneous fault detection and control units for multi-agent systems subject to limited communication and energy resources. For this purpose, each agent is equipped with a single module that generates both the residual signal for the fault detection task, as well as the control input of each agent for the tracking objective. To reduce the communication among the agents, an event-triggered data transmission paradigm is considered by using a dynamic triggering rule which results in higher data transmission reduction in comparison with the static triggering condition. Moreover, the proposed dynamic observer-based structure for the detector-controller module provides more degrees of freedom compared to the static Luenberger observer. The design parameters are obtained by solving a multi-objective optimisation problem considering the fault detection, tracking, and communication objectives. Simulation results illustrate the effectiveness and capabilities of the proposed method.

Event-triggered fault detection for discrete-time LPV systems

In this paper, a new event-triggering mechanism is proposed for the problem of fault detection (FD) in discrete-time linear parameter-varying (LPV) systems. A parameter-dependent event-based observer is designed as the residual generator, that only uses the sensor and scheduling variables data that are transmitted only when they are needed. Toward this goal, based on the concept of input-to-state stability, a new formulation is presented to satisfy the H − performance measures and for each performance index, sufficient conditions are given in terms of linear matrix inequalities problems. It is shown that through two event-triggered data transmission mechanisms, the amount of data sent to the fault detection module is decreased significantly. Simulation results demonstrate the effectiveness of the proposed design methodology.