A Formal Modeling Framework for Anaerobic Digestion Systems

in IEEE UKSim-AMSS Int. Conference on Modelling and Simulation, Cambridge, UK, 2015 (2015, March)

The complexity of modeling the anaerobic digestion process meets the difficulty to describe and analyze them mathematically. In this paper, a simplified mathematical model for anaerobic digestion process ... [more ▼]

The complexity of modeling the anaerobic digestion process meets the difficulty to describe and analyze them mathematically. In this paper, a simplified mathematical model for anaerobic digestion process of organic matter, in a continuous stirred tank reactor is proposed. With the aim of upgrading the produced biogas and integrate biogas plants in a virtual power plant, new control inputs reflecting addition of stimulating substrates (acetate and bicarbonate) are added. Based on two step (acedogenesis-methanogenesis) mass balance non linear model, a step-by-step model parameter’s identification procedure is presented in the first step, then in the second step, the yield coefficients and the microbial growth rates are estimated when the later is assumed to be unknown a priori. [less ▲]

Decentralized Dynamic Observer-Based Control for Large Scale Nonlinear Uncertain Systems

in American Control Conference ACC 2015, Chicago, USA (2015)

The objective of this paper is to propose a decentralized control for a class of large scale uncertain systems. These systems consist of interconnected subsystems where the nonlinear interconnections are ... [more ▼]

The objective of this paper is to propose a decentralized control for a class of large scale uncertain systems. These systems consist of interconnected subsystems where the nonlinear interconnections are quadratic bounded. The proposed control is based on a new form of dynamic observer (DO) and the popular used proportional observer (PO) and proportional integral observer (PIO) are only particular cases of it. The control method is derived from the solution of linear matrix inequalities (LMIs), on the basis of the algebraic constraints obtained from the analysis of estimation error. A numerical example is provided to illustrate the effectiveness of the proposed method. [less ▲]

Nonlinear protocols for distributed consensus in directed networks of dynamic agents

in Journal of the Franklin Institute (2015), 352(9), 3645-3669

This paper deals with the distributed consensus problem of multi-agent systems. While existing work mainly considers the design of linear protocols, we derive nonlinear protocols for directed networks of ... [more ▼]

This paper deals with the distributed consensus problem of multi-agent systems. While existing work mainly considers the design of linear protocols, we derive nonlinear protocols for directed networks of dynamic agents with fi xed and switched topologies, respectively. The obtained nonlinear protocols have the same effectiveness as the existing linear protocols, however they can satisfy the input constraints of real world physical systems, as well as the state value restrictions of agents, which ensure the smooth communication of the whole network and the correct data transmission among agents under the limited bandwidth. In contrast to most existing approaches that commonly use the Lyapunov function theory in order to prove the consensus problem, simple and effective mathematical methods are developed here for this purpose. Based on the equivalent in fi nitesimal functions and differentials as well as linear approximations as comparatively simple mathematical tools, we prove that the distributed consensus is asymptotically reachable and derive the group decision values. For balanced topology structures, these nonlinear protocols in particular guarantee that the agents asymptotically reach an average-consensus. Furthermore, the obtained protocols relax the constraints on the communication links among the agents. Finally, simulations comprising the vertical alignment maneuver of a team of unmanned aerial vehicles (UAVs) and the phase synchronization of three oscillators are studied, respectively. The simulation results underline that the developed nonlinear protocols are effective and feasible for distributed consensus in directed networks of dynamic multi-agent systems. [less ▲]

H-infinity Adaptive Observer Design and Parameter Identification for a Class of Nonlinear Fractional-Order Systems

in 53rd IEEE Conference Decision and Control, CDC’14, Los Angeles, USA, 15-17 Dec. 2014 (2014, December)

A Stochastic Cyber-Attack Detection Scheme for Stochastic Control Systems Based on Frequency-Domain Transformation Technique

in Au, Man ho (Ed.) International Conference on Network and System Security, NSS 2014, Xi'An, China, 15-17 October 2014 (2014, October 15)

Based on frequency-domain transformation technique, this paper proposes an attack detection scheme for stochastic control systems under stochastic cyber-attacks and disturbances. The focus is on designing ... [more ▼]

Based on frequency-domain transformation technique, this paper proposes an attack detection scheme for stochastic control systems under stochastic cyber-attacks and disturbances. The focus is on designing an anomaly detector for the stochastic control systems. First, we construct a model of stochastic control system with stochastic cyber-attacks which satisfy the Markovian stochastic process. And we also introduced the stochastic attack models that a control system is possibly exposed to. Next, based on the frequency-domain transformation technique and linear algebra theory, we propose an algebraic detection scheme for a possible stochastic cyber-attack. We transform the detector error dynamic equation into an algebraic equation. By analyzing the rank of the stochastic matrix E(Q (z0)) in the algebraic equation, residual information is obtained and anomalies in the stochastic system are detected. In addition, sufficient and necessary conditions guaranteeing the detectability of the stochastic cyber-attacks are obtained. The presented detection approach in this paper is simple, straightforward and more ease to implement. Finally, the results are applied to some physical systems that are respectively subject to a stochastic data denial-of-service (DoS) attack and a stochastic data deception attack on the actuator. The simulation results underline that the detection approach is efficient and feasible in practical application. [less ▲]

A Real-Time Implementable Model-Predictive Cruise Controller for Electric Vehicles and Energy-Efficient Driving

in IEEE Multi-Conference on Systems and Control (MSC), Antibes, France, Oct. 2014 (2014, October)

This paper presents a novel energy-efficient model-predictive cruise control formulation for electric vehicles. The controller and the underlying dynamic model are designed to meet the properties of a ... [more ▼]

This paper presents a novel energy-efficient model-predictive cruise control formulation for electric vehicles. The controller and the underlying dynamic model are designed to meet the properties of a series-production electric vehicle whose characteristics are identified by measurements. A predictive eco-cruise controller involves the minimisation of a compromise between terms related to driving speed and energy consumption which are in general both described by nonlinear differential equations. In this work, a coordinate transformation is used which leads to a linear differential motion equation without loss of information. The energy consumption map is approximated by the maximum of a set of linear functions which is implicitly determined in the optimisation problem. The reformulations finally lead to a model-predictive control approach with quadratic cost function, linear prediction model and linear constraints that corresponds to a piecewise linear system behaviour and allows a fast real-time implementation with guaranteed convergence. Simulation results of the MPC controller in closed-loop operation finally show the effectiveness of the approach. [less ▲]

Robust H ∞ cyber-attacks estimation for control systems

in Proceedings of the 33rd CCC, Nanjing 28-30 July 2014 (2014, July 28)

This paper deals with the robust H ∞ cyber-attacks estimation problem for control systems under stochastic cyber-attacks and disturbances. The focus is on designing a H ∞ lter which maximize the attack ... [more ▼]

This paper deals with the robust H ∞ cyber-attacks estimation problem for control systems under stochastic cyber-attacks and disturbances. The focus is on designing a H ∞ lter which maximize the attack sensitivity and minimize the effect of disturbances. The design requires not only the disturbance attenuation, but also the residual to remain the attack sensitivity as much as possible while the effect of disturbance is minimized. A stochastic model of control system with stochastic cyber-attacks which satisfy the Markovian stochastic process is constructed. And we also present the stochastic attack models that a control system is possibly exposed to. Furthermore, applying H ∞ ltering technique-based on linear matrix inequalities (LMIs), the paper obtains suf cient conditions that ensure the ltering error dynamic is asymptotically stable and satis es a prescribed ratio between cyber-attack sensitivity and disturbance sensitivity. Finally, the results are applied to the control of a Quadruple-tank process (QTP) under a stochastic cyber-attack and a stochastic disturbance. The simulation results underline that the designed lters is effective and feasible in practical application. [less ▲]

A Novel Model-Predictive Cruise Controller for Electric Vehicles and Energy-Efficient Driving

in A Novel Model-Predictive Cruise Controller for Electric Vehicles and Energy-Efficient Driving (2014, July)

This paper presents a novel energy-efficient model-predictive cruise control formulation for electric vehicles. A predictive eco-cruise controller involves the minimisation of a compromise between terms ... [more ▼]

This paper presents a novel energy-efficient model-predictive cruise control formulation for electric vehicles. A predictive eco-cruise controller involves the minimisation of a compromise between terms related to driving speed and energy consumption which are in general both described by nonlinear differential equations. In this work, a coordinate transformation is used which leads to a linear differential motion equation without loss of information. The energy consumption is modeled by the maximum of a set of linear functions which is determined implicitly by the optimisation problem and thus leads to a piecewise linear model. The reformulations finally result in a model-predictive control approach with quadratic cost function, linear prediction model and linear constraints that corresponds to a piecewise linear system behaviour and allows a fast real-time implementation with guaranteed convergence. The controller and the underlying dynamic model are designed to meet the properties of a series-production electric vehicle whose characteristics are identified by measurements. Simulation results of the MPC controller and the simulation model in closed-loop operation finally provide a proof of concept. [less ▲]

Chaos in a Fractional-Order Cancer System

in European Control Conference (ECC), Strasbourg, France, 24 - 27 June 2014 (2014, June)

Observer Design for a Nonlinear Minimal Model of Glucose Disappearance and Insulin Kinetics

in The 7th International Conference on Bio-inspired Systems and Signal Processing BIOSIGNALS, Angers, France, 3-6 March 2014 (2014, March)