Output Regulation of Stochastic Sampled-Data Systems with Post-processing Internal Model

This paper deals with the output regulation problem (ORP) of a linear time-invariant (LTI) system in the presence of sporadically sampled measurement streams with the inter-sampling intervals following a stochastic process. Under such sporadically available measurement streams, a regulator consisting of a hybrid observer, continuous-time post-processing internal model, and stabilizer are proposed, which resets with the arrival of new measurements. The resulting system exhibits a deterministic behavior except for the jumps that occur at random sampling times and therefore the overall closed-loop system can be categorized as a piecewise deterministic Markov process (PDMP). In existing works on ORPs with aperiodic sampling, the requirement of boundedness on inter-sampling intervals precludes extending the solution to the random sampling intervals with possibly unbounded support. Using the Lyapunov-like theorem for the stability analysis of stochastic systems, we offer sufficient conditions to ensure that the overall closed-loop system is mean exponentially stable (MES) and the objectives of the ORP are achieved under stochastic sampling of measurement streams. The resulting LMI conditions lead to a numerically tractable design of the hybrid regulator. Finally, with the help of an illustrative example, the effectiveness of the theoretical results are verified

Optimal State Estimation of Nonlinear Dynamic Systems

An optimal estimator for continuous nonlinear systems with nonlinear dynamics, and nonlinear measurement based on the continuous least square error criterion is derived. The solution is exact, explicit, in closed form and gives recursive formulas of the optimal filter. For the derivation of the filter, the following elements are combined: (i) the least squares (LS) criterion based on statistical-deterministic-likelihood approach to estimation; (ii) the state-dependent coefficient (SDC) form representation of the nonlinear system; and (iii) the calculus of variation. The resulting filter is optimal per sample. The filter’s gains need the solution of a nonsymmetric differential matrix Riccati equation. The stability of the estimator is investigated. The performances are demonstrated by simulation of the Van der Pol equation with noisy nonlinear measurement, and system driving noise

Balanced Truncation of Networked Linear Passive Systems

This paper studies model order reduction of multi-agent systems consisting of identical linear passive subsystems, where the interconnection topology is characterized by an undirected weighted graph. Balanced truncation based on a pair of specifically selected generalized Gramians is implemented on the asymptotically stable part of the full-order network model, which leads to a reduced-order system preserving the passivity of each subsystem. Moreover, it is proven that there exists a coordinate transformation to convert the resulting reduced-order model to a state-space model of Laplacian dynamics. Thus, the proposed method simultaneously reduces the complexity of the network structure and individual agent dynamics, and it preserves the passivity of the subsystems and the synchronization of the network. Moreover, it allows for the a priori computation of a bound on the approximation error. Finally, the feasibility of the method is demonstrated by an example

A Review of Energy Management Systems and Organizational Structures of Prosumers

Thisreviewprovidesthestateoftheartofenergymanagementsystems(EMS)and organizationalstructuresofprosumers.Integrationofrenewableenergysources(RES)intothe householdbringsnewchallengesinoptimaloperation,powerquality,participationintheelectricity marketandpowersystemstability.AcommonsolutiontothesechallengesistodevelopanEMSwith differentprosumerorganizationalstructures.EMSdevelopmentisamultidisciplinaryprocessthat needstoinvolveseveralaspectsofobservation.Thispaperprovidesanoverviewoftheprosumer organizationalandcontrolstructures,typesandelements,predictionmethodsofinputparameters, optimizationframeworks,optimizationmethods,objectivefunctions,constraintsandthemarket environment.Specialattentionisgiventotheoptimizationframeworkandpredictionofinput parameters,whichrepresentsroomforimprovement,thatmitigatetheimpactofuncertainties associatedwithRES-basedgeneration,consumptionandmarketpricesonoptimaloperation.Peer ReviewedObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.2 - Per a 2030, augmentar substancialment el percentatge d’energia renovable en el con­junt de fonts d’energiaObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.a - Per a 2030, augmentar la cooperació internacional per tal de facilitar l’accés a la investigació i a les tecnolo­gies energètiques no contaminants, incloses les fonts d’energia renovables, l’eficiència energètica i les tecnologies de combustibles fòssils avançades i menys contaminants, i promoure la inversió en infraestructures energètiques i tecnologies d’energia no contaminantObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No ContaminantPostprint (published version

Model Predictive Control of a Road Junction

This paper presents a model predictive control (MPC) approach for optimally managing the traffic light (TL) signals at a road junction. The objective is to improve queue balancing compared to traditional control strategies where TL signals are periodic. The resulting MPC optimization problem is of quadratic mixed-integer nature. The proposed approach is validated via simulations based on a real scenario

Supervisory control of complex propulsion subsystems

Modern gasoline and diesel combustion engines are equipped with several subsystems with the goal to reduce fuel consumption and pollutant exhaust emissions. Subsystem synergies could be harnessed using the supervisory control approach. Look-ahead information can be used to potentially optimise power-train control for real time implementation. This thesis delves upon modelling the exhaust emissions from a combustion engine and developing a combined equivalent objective metric to propose a supervisory controller that uses look-ahead information with the objective to reduce fuel consumed and exhaust emissions. In the first part of the thesis, the focus is on diesel engine application control for emissions and fuel consumption reduction.\ua0Model of exhaust emissions in a diesel engine obtained from a combination of nominal engine operation and deviations are evaluated for transient drive cycles.\ua0The look ahead information as a trajectory of vehicle speed and load over time is considered.\ua0The supervisory controller considers a discrete control action set over the first segment of the trip ahead.\ua0The cost to optimise is defined and pre-computed off-line for a discrete set of operating conditions.\ua0A full factorial optimisation carried out off-line is stored on board the vehicle and applied in real-time.\ua0In a first proposal, the subsystem control of the after-treatment system comprising the lean NOx trap and the selective reduction catalyst is considered.\ua0As a next iteration, the combustion engine is added to the control problem.\ua0Simulation comparison of the controllers with the baseline controller offers a 1 % total fuel equivalent cost improvement while offering the flexibility to tailor the controller for different cost objective. In the second part of the thesis, the focus is on cold-start emissions control for modern gasoline engines.\ua0Emissions occurring when the engine is started until the catalyst is sufficiently warm, contribute to a significant proportion of tailpipe pollutant emissions.\ua0Electrically heated catalyst (EHC) in the three way catalyst (TWC) is a promising technology to reduce cold-start emissions where the catalyst can be warmed up prior to engine start and continued after start.\ua0A simulation framework for the engine, TWC with EHC with focus on modeling the thermal and chemical interactions during cold-start was developed.\ua0An evaluation framework with a proposed equivalent emissions approach was developed considering the challenges associated with cold-start emission control.\ua0An equivalent emission optimal post-heating time for the EHC is proposed that adapts to information which is available in a real-time on-line implementation.\ua0The proposed controller falls short of just 1 % equivalent emissions compared to the optimal case