Walter Lucia

Walter Lucia
Concordia University Montreal · Concordia Institute for Information Systems Engineering

PhD

About

78
Publications
6,733
Reads
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530
Citations
Citations since 2016
60 Research Items
505 Citations
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
Introduction
Walter Lucia currently works at the Concordia Institute for Information Systems Engineering, Concordia University, Montreal. Walter does research in Control Systems Engineering. In particular his research interests currently are: Cyber-Physical Systems, Fault-Tolerant Control, Model Predictive Control and Autonomous Vehicles
Additional affiliations
September 2015 - February 2016
Carnegie Mellon University
Position
  • Visiting Researcher
March 2013 - December 2013
Northeastern University
Position
  • Researcher
Education
November 2012 - February 2015
Università della Calabria
Field of study
  • Control Engineering
January 2009 - March 2011
Università della Calabria
Field of study
  • Automation engineering
September 2005 - December 2008
Università della Calabria
Field of study
  • Computer engineering

Publications

Publications (78)
Article
The paper addresses the obstacle avoidance motion planning problem for ground vehicles operating in uncertain environments. By resorting to set-theoretic ideas, a receding horizon control algorithm is proposed for robots modelled by linear time-invariant (LTI) systems subject to input and state constraints and disturbance effects. Sequences of inne...
Conference Paper
Full-text available
In this paper we develop an obstacle avoidance control scheme for autonomous vehicles. The strategy is based on Command Governor (CG) ideas that are here extended to take into account non-convex and time-varying constraints arising in path planning obstacle avoidance problems. As one of its main merits, the path planner module of the proposed archi...
Conference Paper
In this paper we address the obstacle avoidance motion planning problem for leader-follower vehicles configurations operating in static environments. By resorting to settheoretic ideas, a receding horizon control algorithm is proposed for robots modelled by linear time-invariant (LTI) systems subject to input and state constraints. Terminal robust...
Conference Paper
Full-text available
This paper considers the obstacle avoidance motion planning problem for autonomous vehicles operating in uncertain dynamic environments. By resorting to a set-theoretic approach, a receding horizon control algorithm is developed for robots described by linear time-invariant (LTI) systems subject to disturbance effects, input and state constraints....
Article
Full-text available
A Model Predictive Control (MPC) strategy for nonlinear Networked Control Systems (NCS) described by a polynomial plants subject to input, state constraints and data-losses is introduced. The results here proposed represent a significant extension to the polynomial framework of a recent Receding Horizon Control (RHC) scheme developed for input-satu...
Article
This work proposes an alternative technique to design an incremental stabilizing output-feedback control law for constrained discrete-time linear parameter-varying (LPV) systems. We use an extended state space composed of the system's state and control variables and use the control variations as the control inputs. We employ polyhedral sets’ Positi...
Article
Encrypted control systems were introduced to enhance the security of cyber-physical systems, which outsource control action computations to a third-party platform. To protect the confidentiality of the transmitted data, homomorphic encryption schemes are particularly appealing for their capability of allowing computations on encrypted data. By cons...
Article
The command governor (\(CG\)) is a useful strategy to avoid constraints violation in case of control reconfiguration or operational conditions changes, like switched systems mode changes. In general, the structure of the \(CG\) specializes in producing an alternative reference signal to drive a closed-loop system to the desired reference while avoi...
Article
In the last decades, several cyber-threats against Cyber-Physical Systems (CPSs) have been reported. Of particular interest are the classes of network attacks capable of affecting the control systems' performance while remaining undetectable. In this paper, under some conditions, we show the existence of a novel class of finite-time undetectable at...
Article
Motivated by its applications to real-world sensor networks, the problem of connectivity estimation of random graphs is investigated. Random graphs are utilized here for representing networks with probabilistic node-to-node communication links. In this context, the unknown probability matrix of the network characterizes the existence of graph edges...
Article
We propose an encrypted set-theoretic model predictive control (ST-MPC) strategy for cloud-based networked control systems. In particular, we consider a scenario where the plant is subject to state and input constraints, and a curious but honest cloud provider is available to implement the control logic remotely. We address the inherent privacy iss...
Article
In this technical note, the safety and reference tracking control problems for Cyber-Physical Systems (CPSs) equipped with authenticated communication channels are addressed. In this class of CPSs, network attacks can break the feedback loop at two different points for an arbitrarily long period. In this scenario, we design a novel control architec...
Article
This brief proposes a novel solution to the trajectory tracking control problem for input-constrained differential-drive robots. In particular, we develop a robust set-based receding horizon tracking scheme capable of dealing with state-dependent input constraints arising when the vehicle’s dynamics are approached by a standard feedback linearizati...
Article
This paper proposes a novel procedure to design a control invariant region for feedback-linearized car-like vehicles subject to linear and steering velocity constraints. To this end, first, it is formally proved that the state-dependent input constraints acting on the feedback-linearized car model admit a worst-case circular inner approximation. Th...
Article
Full-text available
A covert channel is a communication channel that is not intended to exist, and that can be used to transfer information in a manner that violates the system security policy. Attackers can abuse such channels to exfiltrate sensitive information from cyber-physical systems (CPSs), for example to leak the confidential or proprietary parameters in a co...
Article
Traditional cryptographic approaches may not always be suitable for cyber-physical systems (CPSs). In this correspondence, we present a control-theoretic approach allowing a networked controller and a smart actuator of a stochastic CPS to agree on a common secret key without resorting to classical cryptographic approaches. More precisely, by utiliz...
Article
In this letter, using a control-theoretic approach, we present a covert channel technique, enabling a compromised networked controller to leak information to an eavesdropper who has access to the measurement channel. We demonstrate that this can be achieved without establishing any additional explicit communication channels by properly altering the...
Article
Full-text available
In this paper, the intelligent traffic management within a smart city environment is addressed by developing an ad-hoc model predictive control strategy based on an event-driven formulation. To this end, a constrained hybrid system description is considered for safety verification purposes and a low-demanding receding horizon controller is then der...
Article
In this paper, we face the reference tracking control problem for a system of heterogeneous Multi Unmanned Vehicles (MUVs) moving in a 2-D planar environment. We consider a scenario where each vehicle follows a trajectory imposed by a local planner and where each UV can have different linear dynamics as well as different constraints and disturbance...
Article
In this paper, a robust model predictive control strategy is developed for networked cyber-physical systems under false data injections. The main feature of the proposed scheme relies on the capability to mitigate undesired system behaviors due to external malicious actions. This is achieved by showing that set-membership conditions allow to quickl...
Preprint
In this study, the authors consider the problem of exchanging secrete messages in cyber-physical systems (CPSs) without resorting to cryptographic solutions. In particular, they consider a CPS where the networked controller wants to send a secrete message to the plant. They show that such a problem can be solved by exploiting a Wyner wiretap-like e...
Preprint
Recently, cloud control systems have gained increasing attention from the research community as a solution to implement networked cyber-physical systems (CPSs). Such an architecture can reduce deployment and maintenance costs albeit at the expense of additional security and privacy concerns. In this paper, first, we discuss state-of-the-art securit...
Article
In this article, we propose a networked control architecture to ensure the plant's safety in the presence of cyber‐attacks on the communication channels. In particular, we consider systems subject to both state and input constraints that must be preserved for safety reasons despite any admissible attack scenario. To this end, first, two different d...
Conference Paper
The command governor (CG) is a useful strategy to avoid constraints violation in case of control reconfiguration or operational conditions changes, like switched systems mode changes. In general, the structure of the CG specializes in producing an alternative reference signal to drive a closed-loop system to the desired reference while avoiding con...
Article
Full-text available
In this study, the authors consider the problem of exchanging secrete messages in cyber-physical systems (CPSs) without resorting to cryptographic solutions. In particular, they consider a CPS where the networked controller wants to send a secrete message to the plant. They show that such a problem can be solved by exploiting a Wyner wiretap-like e...
Article
In this paper, we propose a distributed model predictive control strategy for a team of vehicles moving in an unknown obstacle scenario. In particular, we combine receding horizon control arguments with leader-follower formations in order to design a flexible architecture where the vehicle topology, if needed, can be rearranged to better cope with...
Article
In recent years, different solutions have been proposed to detect advanced stealthy cyber-attacks against networked control systems. In this article, we propose a blended detection scheme that properly leverages and combines two existing detection ideas, namely, watermarking and moving target . In particular, a watermarked signal and a nonlinea...
Article
Multi-agent systems are usually equipped with open communication infrastructures to improve interactions efficiency, reliability and sustainability. Although technologically cost-effective, this makes them vulnerable to cyber-attacks with potentially catastrophic consequences. To this end, we present a novel control architecture capable to deal wit...
Conference Paper
This work tackles the problem of controlling quadrotor Unmanned Aerial Vehicles (UAVs) subject to model uncertainties and perturbations. The objective of the paper is to design a sliding mode controller capable of ensuring accurate position and attitude tracking performance while preventing singularity problem in the fast terminal sliding surface....
Article
Full-text available
In this study, the authors deal with the transient stability control problem in smart grids. They consider an operative scenario where a physical fault or a cyber‐attack produces an impulsive perturbation in the state of the system, and a controller must be designed to robustly recover, in a finite‐time, transient stability despite initial perturba...
Article
Full-text available
In this paper, a resilient control strategy against replay attacks is developed for discrete-time linear systems subject to state and input constraints, bounded disturbances and measurement noises. In particular operating scenarios, where adversaries act on the communication network by maliciously repeating data transmitted from the sensor to the c...
Article
In this paper, a sensor stuck fault‐tolerant control framework for linear time‐invariant plant models subject to input/state constraints and bounded disturbances is presented. A receding horizon control reconfigurable scheme is proposed to contrast undesired effects due to sensors malfunctioning. The main merit of this strategy relies on its intrin...
Article
In this paper, we develop an obstacle avoidance control scheme for autonomous aerial vehicles. The strategy is based on command governor (CG) ideas that are here extended to take into account nonconvex constraints typically arising in path planning obstacle avoidance problems. As one of its main merits, the collision avoidance task is accomplished...
Article
In this paper a framework for the formal verification of safety properties of constrained hybrid systems is developed and a stabilization problem is addressed by using model predictive control ideas. By resorting to piecewise affine state space descriptions, system properties are verified by means of forward and backward reachability concepts which...
Article
In this paper, a switched control architecture for constrained control systems is presented. The strategy is based on command governor ideas that are here specialized to 'optimally' schedule switching events on the plant dynamics for improving control performance at the expense of low computational burdens. The significance of the method mainly lie...
Article
This paper presents a fault tolerant control scheme for constrained discrete time linear systems against stuck actuators and bounded disturbances. The results here proposed are a significant generalization of a similar algorithm which has been designed only to manage healthy/out-of-service actuator units. A key feature of the proposed scheme consis...
Article
Full-text available
In this paper, the problem of designing a compensator capable of ensuring constraint satisfaction and tracking performance for a plant switching among a finite family of constrained linear time-invariant configurations is investigated. We assume that switching occurrences are governed by a logical rule, which prescribes that any information pertain...
Article
A novel receding horizon control scheme is presented in this paper to manage networked leader-follower formation control problems in the presence of time-varying delay and data loss (measurement and feedback packet dropouts) occurrences on the communication and feedback channels. One of the main novelties of the proposed paradigm relies on the use...
Article
Full-text available
In this paper, we present a novel receding horizon control scheme for solving the formation problem of leader–follower configurations. The algorithm is based on set-theoretic ideas and is tuned for agents described by linear time-invariant (LTI) systems subject to input and state constraints. The novelty of the proposed framework relies on the capa...
Article
Full-text available
Cyber-physical systems (CPS) embody a tight integration between network-based communications, software, sensors, and physical processes. While the integration of cyber technologies within legacy systems will most certainly introduce opportunities and advancements not yet envisioned, it will undoubtedly also pave the way to misdemeanors that will ex...
Conference Paper
Regulation problems for networked constrained polytopic Linear Parameter Varying (LPV) systems are considered. It is assumed that the communication network is subject to latency effects which result in induced time-varying time-delays on both the control and measurement channels. A novel LPV customization of a recent Receding-Horizon control (RHC)...
Conference Paper
This paper presents a Fault Tolerant Control scheme for constrained discrete time linear systems against stuck actuators and bounded disturbances. The results here proposed are a significant generalization of a similar algorithm which has been designed only to manage healthy/out-of-service in the actuator units. A first key feature is the capabilit...
Article
This paper deals with control problems for networked constrained polytopic Linear Parameter Varying (LPV) systems. A novel LPV customization of a recent Receding Horizon robust Control (RHC) scheme developed for polytopic uncertainty systems is here proposed for the case where command inputs and state measurement are subject to time-varying delays....
Article
In this work we compare the performance of two well known filters for nonlinear models, the Extended Kalman Filter and the Unscented Kalman Filter, in estimating the position and orientation of a mobile robot. The two filters fuse the measurements taken by ultrasonic sensors located onboard the robot. The experimental results on real data show a su...
Conference Paper
Full-text available
In this paper a switched control architecture for constrained control systems is presented. The strategy is based on Command Governor (CG) ideas that are here specialized in order to jointly take into account switching events on the plant dynamics and time-varying constraints. The significance of the method relies in its capability to avoid constra...
Article
Full-text available
In this brief, a receding horizon control scheme for solving the obstacle avoidance motion planning problem of autonomous vehicles operating in uncertain dynamic environments is developed. By considering robots described by discrete-time linear time-invariant models, we propose a set-theoretic-based architecture to deal with disturbance effects, an...
Article
The paper addresses the obstacle avoidance motion planning problem for ground vehicles operating in uncertain environments. By resorting to set-theoretic ideas and sum of squares (SOS) decomposition techniques, a receding horizon control algorithm is proposed for robots modelled by polynomial systems subject to input, state and nonholonomic constra...
Thesis
Full-text available
This dissertation analyzes the obstacle avoidance motion planning problem for ground and aerial vehicles operating in uncertain environments. By resorting to settheoretic and predictive schemes based ideas, receding horizon control algorithms are proposed as an effective solution for the obstacle avoidance problem. Two obstacle scenarios with diffe...
Conference Paper
Full-text available
This paper proposes a Model Predictive Control (MPC) strategy to address regulation problems for constrained polytopic Linear Parameter Varying (LPV) systems subject to input and state constraints in which both plant measurements and command signals in the loop are sent through communication channels subject to time-varying delays (Networked Contro...
Article
Full-text available
The paper addresses the obstacle avoidance motion planning problem for ground vehicles operating in uncertain environments. By resorting to set-theoretic ideas, a receding horizon control algorithm is proposed for robots modelled by linear time-invariant (LTI) systems subject to input and state constraints and disturbance effects. Sequences of inne...
Article
Full-text available
The paper addresses the obstacle avoidance motion planning problem for ground vehicles operating in uncertain environments, i.e. time-varying obstacle scenarios are taken into consideration. By resorting to set-theoretic ideas and sum of squares (SOS) decomposition techniques, a receding horizon control algorithm is proposed for robots modelled by...
Conference Paper
Full-text available
In this work we compare the performance of two algorithms, respectively based on the Extended Kalman Filter and the Unscented Kalman Filter, for the mobile robot localization and environment reconstruction problem. The proposed algorithms do not require any assumption on the robot working space: they are driven only by the measurements taken using...
Conference Paper
Full-text available
In this work we compare the performance of two well known filters for nonlinear models, the Extended Kalman Filter and the Unscented Kalman Filter, in estimating the position and orientation of a mobile robot. The two filters are driven by measurements taken by ultrasonic sensors that are located onboard the robot, and a switching sensors activatio...

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