Papers by Emanuele Garone
Novel distributed supervisory strategies for multi-agent linear systems connected via data networ... more Novel distributed supervisory strategies for multi-agent linear systems connected via data networks and subject to coordination constraints are presented in this paper. Such a coordination-by-constraint paradigm is based on the online management of the prescribed set points and it is characterized by a set of spatially distributed dynamic systems, connected via communication channels, with possibly dynamical coupling amongst them which need to be supervised and coordinated in order to accomplish their overall objective. Two distributed strategies will be fully described and analysed. First, a " sequential " distributed strategy will be presented where only one agent per decision time is allowed to manipulate its own reference signal. Such a strategy will be instrumental to introduce a more effective " parallel " distributed strategy, in which all agents are allowed, under certain conditions, to modify their own reference signals simultaneously. Finally, some cases of study will be presented to show the effectiveness of the proposed methods.
2008 5th International Symposium on Mechatronics and Its Applications, 2008
This paper presents an adaptive actuator allocation scheme that is fault-tolerant with respect to... more This paper presents an adaptive actuator allocation scheme that is fault-tolerant with respect to actuator faults and loss of effectiveness. The main idea is to use an ad-hoc online parameter estimator coupled with an allocation algorithm to perform on-line control reconfiguration whenever necessary. A preliminary algorithm is proposed for nonlinear discrete-time systems. Its main properties are summarized in the disturbance-free case and its effectiveness shown by means of two numerical examples, the second one dealing with driving/braking loss of effectiveness due to tire/surface contact force variations in 4WS4WD terrestrial vehicles.
2014 American Control Conference, 2014
This paper provides a tutorial overview of reference governors and command governors, which are a... more This paper provides a tutorial overview of reference governors and command governors, which are addon control schemes for reference supervision and constraint enforcement in closed-loop feedback control systems. The main approaches to the development of such schemes for linear and nonlinear systems are described. The treatment of unmeasured disturbances and parametric uncertainties is addressed. Generalizations to extended command governors, feedforward reference governors, reduced order reference governors, parameter governors, networked reference governors, decentralized reference governors, and virtual state governors are summarized. Examples of applications of these techniques to automotive systems are given. A comprehensive list of references is included. Comments comparing reference and command governor approaches with Model Predictive Control and input shaping, and on future directions in reference and command governor research are included.
International Journal of Robust and Nonlinear Control, 2010
This paper presents a fault-tolerant adaptive control allocation scheme for overactuated systems ... more This paper presents a fault-tolerant adaptive control allocation scheme for overactuated systems subject to loss of effectiveness actuator faults. The main idea is to use an 'ad hoc' online parameters estimator, coupled with a control allocation algorithm, in order to perform online control reconfiguration whenever necessary. Time-windowed and recursive versions of the algorithm are proposed for nonlinear discrete-time systems and their properties analyzed. Two final examples have been considered to show the effectiveness of the proposed scheme. The first considers a simple linear system with redundant actuators and it is mainly used to exemplify the main properties and potentialities of the scheme. In the second, a realistic marine vessel scenario under propeller and thruster faults is treated in full details.
— This paper presents a novel enhanced algorithm belonging to the class of so-called Feed-Forward... more — This paper presents a novel enhanced algorithm belonging to the class of so-called Feed-Forward Command Governor (FF-CG) strategies, characterized by the absence of any explicit on-line measure (or estimation) of the state, which have been recently proposed in [1], [2] for input/state constrained discrete-time linear systems subject to bounded disturbances. In fact, while in all traditional CG schemes the set-point manipulation is undertaken on the basis of either the actual measure of the state or its suitable estimation, feed-forward strategies are characterized by the fact that the CG design problem is explicitly solved, with limited performance degradation and with similar properties, in the absence of such a measure. This is achieved by forcing the system evolutions to stay " not too far " from the space of feasible steady-states. Although effective also in the case of bounded disturbances, the performance of earlier FF-CG schemes [1], [2] was mainly limited by the fact that such strategies were instructed to maintain constant their actions for a prescribed number of sampling steps between two subsequent CG action computation. Here such a restriction is completely removed and a novel class of FF-CG schemes able to update their actions at each sampling step is discussed. Finally, in order to evaluate the effectiveness of the proposed solution, numerical simulations on a physical plant have been undertaken and comparison results reported.
A distributed constrained supervisory strategy for large-scale spatially distributed systems is p... more A distributed constrained supervisory strategy for large-scale spatially distributed systems is presented and applied to a networked water distribution system. The aim is at reconfiguring, whenever necessary in response to different supply downstream demands, the nominal set-points to the tank water levels so that all prescribed coordination and operational constraints are enforced during the system evolutions and sustainable equilibria are reached. The presented supervision strategy follows a coordination-by-constraint approach and is based on Feed-Forward Command Governor (FF-CG) ideas. The effectiveness of the strategy is shown in the final example where the supervision of an eight-tank interconnected system is considered.
— In this paper we present a complete liveliness analysis for a novel distributed supervision str... more — In this paper we present a complete liveliness analysis for a novel distributed supervision strategy for multi-agent systems connected via data links and subject to coordination constraints. A geometrical Constraints Qualification (CQ) condition on the prescribed constraints is proposed whose fulfilment avoid deadlock situations and ensure viable solutions. Such a coordination paradigm, referred to as coordination-by-constraint, is accomplished by solving on-line in a distributed manner a convex optimization problem involving the modification of the prescribed nominal set-point of each agent. A sequential strategy, where only one agent at the time is allowed to manipulate its own setpoint, is discussed and it is shown that the solvability at each time instant of the underlying optimization problem, unlike the centralized case, can be ensured only if the constraints satisfy such a (CQ) condition, which can be easily checked from the outset via a numerical procedure provided in the paper. An algorithm to compute Constraints Qualified (CD) arbitrarily accurate inner approximations of the original constraint set is also presented and exemplified in final example.
Graph colorability theory is shown here to be instrumental for the improvement of scalability and... more Graph colorability theory is shown here to be instrumental for the improvement of scalability and performance of recently introduced distributed non-cooperative sequential Command Governor (CG) strategies. Such properties were limited in earlier distributed CG schemes because the structure of constraints was not taken into account in their implementation. Here, by exploiting the idea that agents that are not jointly involved in any coupling constraint can simultaneously update their control actions, this is done by grouping all agents in the network into particular subsets (Turns) and allowing all agents belonging to a single turn to update simultaneously their commands while agents in other turns are instructed to keep applying their current commands. Graph colorability concepts and results are used to determine the minimum number of independent turns and distribute exclusively agents into them. A Turn-Based distributed CG strategy is therefore proposed and its main properties analyzed. A final example is also presented to illustrate the effectiveness of the proposed strategy by comparisons.
International Journal of Robust and Nonlinear Control, 2014
2015 American Control Conference (ACC), 2015
This paper introduces a novel closed-form strategy that dynamically modifies the reference of a p... more This paper introduces a novel closed-form strategy that dynamically modifies the reference of a pre-compensated nonlinear system to ensure the satisfaction of a set of convex constraints. The main idea consists of translating constraints in the state space into constraints on the Lyapunov function and then modulating the reference velocity so as to limit the value of the Lyapunov function. The theory is introduced for general nonlinear systems subject to convex constraints. In the case of polyhedric constraints, an explicit solution is provided for the large and highly relevant class of nonlinear systems whose Lyapunov function is lower-bounded by a quadratic form. In view of improving performances, further specializations are provided for the relevant cases of linear systems and robotic manipulators.
A distributed constrained supervisory strategy for large-scale spatially distributed systems is p... more A distributed constrained supervisory strategy for large-scale spatially distributed systems is presented and applied to a networked water distribution system. The aim is at reconfiguring, whenever necessary in response to different supply downstream demands, the nominal set-points to the tank water levels so that all prescribed coordination and operational constraints are enforced during the system evolutions and sustainable equilibria are reached. The presented supervision strategy follows a coordination-by-constraint approach and is based on Feed-Forward Command Governor (FF-CG) ideas. The effectiveness of the strategy is shown in the final example where the supervision of an eight-tank interconnected system is considered.
In this paper we present a novel distributed supervision strategy for networks of linear locally ... more In this paper we present a novel distributed supervision strategy for networks of linear locally regulated and possibly dynamically coupled systems connected via data links and subject to coordination constraints on the evolutions of relevant variables of them. Such a coordination-by-constraint paradigm is accomplished by resorting to a Distributed Command Governor approach where each agent of the strategy is in charge to locally modify, whenever necessary and on the basis of a reduced amount of data exchanged with the other agents, the prescribed set-points to the regulated subsystems so as that the global pointwise-in-time coordination constraints are satisfied along the overall network evolutions. A sequential strategy, where only one agent per time is allowed to manipulate its own reference signal, is fully described and analyzed. The constrained coordination of a network of dynamically coupled eight water tanks is presented as an example in order to show the effectiveness of the proposed method.
Proceedings of the American Control Conference
In this paper we present a stochastic strategy for energy-efficient joint sensors selection/infor... more In this paper we present a stochastic strategy for energy-efficient joint sensors selection/information routing in Wireless Sensor Networks with general communication graph topology. Such a scheme generalizes the early stochastic Sensor scheduling approach proposed in [1], [2], where the communication graph was limited to be a tree. The idea is to associate at each edge of the (directed) communication graph a probability to transmit and thus to perform the sensor selection and the information routing through a stochastic mechanism. Being the problem of optimally determining the edge probabilities computationally intractable, a heuristic based on the use of spanning trees is introduced together with some theoretical results that allow evaluation of the optimality gap. A final numerical example shows the effectiveness of the proposed method.
IEEE Transactions on Automatic Control
In this technical note, we present a Receding Horizon Control (RHC) design method for linear para... more In this technical note, we present a Receding Horizon Control (RHC) design method for linear parameter varying (LPV) systems subject to input and/or state constraints based on a class of nonlinearly parameterized Lyapunov functions recently introduced by Guerra and Vermeiren. As it will be made clear, their use gives rise to less conservative stabilizability conditions w.r.t. those arising from quadratic Lyapunov functions. A workable convex optimization procedure is first presented for control design purposes which allows the synthesis of stabilizing scheduling state-feedback control laws complying with the prescribed constraints. This control design method is then arranged into a receding horizon framework and its feasibility and stability properties are carefully analyzed. Numerical comparisons with existing RHC methods for LPV systems are reported in the final example.
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Papers by Emanuele Garone