... AUTHORS: Peter P. Groumpos, Nick T. Koussoulas (Coordinator), John Lygeros, Anthony Tzes Depa... more ... AUTHORS: Peter P. Groumpos, Nick T. Koussoulas (Coordinator), John Lygeros, Anthony Tzes Department of Electrical and Computer Engineering ... K. Sivashanmugam, A. Sheth, J. Miller, K. Verma,R. Aggarwal, P. Rajasekaran: Metadata and Semantics for Web Services and ...
ABSTRACT This paper addresses the exploitation of the combined potential of the directly-actuated... more ABSTRACT This paper addresses the exploitation of the combined potential of the directly-actuated and the underactuated control authorities of unmanned aerial vehicles with thrust-vectoring actuation. For the modeling, control synthesis and experimental evaluation a custom developed unmanned tri-tiltrotor is employed, equipped with rotor-tilting mechanisms which enable the direct actuation of its longitudinal dynamics, while retaining the standard body-pitching underactuated authority. An explicit model predictive control scheme relying on constrained multiparametric optimization is proposed for the dual-authority optimal control. The backbone of this scheme is a modeling representation that incorporates the separate internal dynamics of the two actuation principles and their interferences as they concurrently act on the free-flying vehicle body, while tractably representing their differentiated effects on the evolution of the longitudinal dynamics. This paper additionally presents the key implemented features that enable the autonomous operation of the employed tilt-rotor platform, in order to provide a reliable testbed for experimental evaluation. Finally, extensive experimental studies which conclusively validate this strategy’s increased efficiency are demonstrated.
ABSTRACT The coverage control problem for mobile sensor networks in non-convex environments is ad... more ABSTRACT The coverage control problem for mobile sensor networks in non-convex environments is addressed in this article. The sensing model of each node is assumed identical and radial either in the geodesic or the Euclidean sense. Depending on the selected metric, the partitioning of the non-convex domain can result either in the geodesic or the Euclidean Voronoi diagram. The coverage problem is examined from a two-fold aspect: based on a)proper selection of the sensing model, and b)the partitioning scheme, as directed by the application itself. Distributed collaborative control schemes are developed, further validated via extensive numerical studies.
ABSTRACT This paper addresses the problem of robust flight control of unmanned rotorcrafts, by pr... more ABSTRACT This paper addresses the problem of robust flight control of unmanned rotorcrafts, by proposing and experimentally evaluating a real-time robust model predictive control scheme in various challenging conditions, aiming to capture the demanding nature of the potential requirements for their efficient and safe integration in real-life operations. The control derivation process is based on state space representations applicable in most rotorcraft configurations and incorporate the effects of external disturbances. Exploiting this modeling approach, two different unmanned rotorcraft configurations are presented and experimentally utilized. The formulated control strategy consists of a receding horizon scheme, the optimization process of which employs the minimum peak performance measure, while incorporating and accounting for the modeled dynamics and input and state constraints. This strategy aims to ensure the minimum possible deviation subject to the worst-case disturbance, while robustly respecting and satisfying the physical limitations of the system, or a set of mission-related requirements, as encoded in the constraints. The proposed framework is further augmented in order to provide obstacle avoidance capabilities into a unified scheme. Multiparametric methods were utilized in order to provide an explicit solution to the controller computation optimization problem, therefore allowing for fast real-time execution and seamless integration into any digital avionics system. The efficiency of the proposed strategy is validated via several experimental case studies on the two unmanned rotorcraft platforms. The experiments set consists of: trajectory tracking subject to atmospheric disturbances, slung load operations, fast highly disturbed maneuvers, collisions handling, as well as avoidance of known obstacles.
ABSTRACT The objective of this article is the detection of tip-fractures as faults in the normal ... more ABSTRACT The objective of this article is the detection of tip-fractures as faults in the normal operation of an Atomic Force Microscope (AFM), where the system's characteristics (damping, tip-radius) vary. The system is modeled as a vibrating cantilever beam whose deflection can be measured. The measurements are assumed to be corrupted by noise within a priori known magnitude. The certainty sets within which the nominal time-varying parameters of the AFM reside are computed via a variation of an ellipsoidal Set Membership Identification technique. The fault is captured at the time instant of the existence of an outlier-measurement.
The robust stabilization problem of a certain class of nonlinear systems is considered. The under... more The robust stabilization problem of a certain class of nonlinear systems is considered. The underlying assumption is that the model uncertainty satisfies the structural matching conditions. Strict matching conditions are exploited and the effect of the induced input field uncertainty is compensated. The robust stabilization for this class of feedback linearizable systems is attained through an optimal control problem guaranteeing robustness against the uncertainties. The solution is obtained through the solution of an algebraic Riccati equation. Sufficient conditions are provided to establish the robust stability of the system
... AUTHORS: Peter P. Groumpos, Nick T. Koussoulas (Coordinator), John Lygeros, Anthony Tzes Depa... more ... AUTHORS: Peter P. Groumpos, Nick T. Koussoulas (Coordinator), John Lygeros, Anthony Tzes Department of Electrical and Computer Engineering ... K. Sivashanmugam, A. Sheth, J. Miller, K. Verma,R. Aggarwal, P. Rajasekaran: Metadata and Semantics for Web Services and ...
ABSTRACT This paper addresses the exploitation of the combined potential of the directly-actuated... more ABSTRACT This paper addresses the exploitation of the combined potential of the directly-actuated and the underactuated control authorities of unmanned aerial vehicles with thrust-vectoring actuation. For the modeling, control synthesis and experimental evaluation a custom developed unmanned tri-tiltrotor is employed, equipped with rotor-tilting mechanisms which enable the direct actuation of its longitudinal dynamics, while retaining the standard body-pitching underactuated authority. An explicit model predictive control scheme relying on constrained multiparametric optimization is proposed for the dual-authority optimal control. The backbone of this scheme is a modeling representation that incorporates the separate internal dynamics of the two actuation principles and their interferences as they concurrently act on the free-flying vehicle body, while tractably representing their differentiated effects on the evolution of the longitudinal dynamics. This paper additionally presents the key implemented features that enable the autonomous operation of the employed tilt-rotor platform, in order to provide a reliable testbed for experimental evaluation. Finally, extensive experimental studies which conclusively validate this strategy’s increased efficiency are demonstrated.
ABSTRACT The coverage control problem for mobile sensor networks in non-convex environments is ad... more ABSTRACT The coverage control problem for mobile sensor networks in non-convex environments is addressed in this article. The sensing model of each node is assumed identical and radial either in the geodesic or the Euclidean sense. Depending on the selected metric, the partitioning of the non-convex domain can result either in the geodesic or the Euclidean Voronoi diagram. The coverage problem is examined from a two-fold aspect: based on a)proper selection of the sensing model, and b)the partitioning scheme, as directed by the application itself. Distributed collaborative control schemes are developed, further validated via extensive numerical studies.
ABSTRACT This paper addresses the problem of robust flight control of unmanned rotorcrafts, by pr... more ABSTRACT This paper addresses the problem of robust flight control of unmanned rotorcrafts, by proposing and experimentally evaluating a real-time robust model predictive control scheme in various challenging conditions, aiming to capture the demanding nature of the potential requirements for their efficient and safe integration in real-life operations. The control derivation process is based on state space representations applicable in most rotorcraft configurations and incorporate the effects of external disturbances. Exploiting this modeling approach, two different unmanned rotorcraft configurations are presented and experimentally utilized. The formulated control strategy consists of a receding horizon scheme, the optimization process of which employs the minimum peak performance measure, while incorporating and accounting for the modeled dynamics and input and state constraints. This strategy aims to ensure the minimum possible deviation subject to the worst-case disturbance, while robustly respecting and satisfying the physical limitations of the system, or a set of mission-related requirements, as encoded in the constraints. The proposed framework is further augmented in order to provide obstacle avoidance capabilities into a unified scheme. Multiparametric methods were utilized in order to provide an explicit solution to the controller computation optimization problem, therefore allowing for fast real-time execution and seamless integration into any digital avionics system. The efficiency of the proposed strategy is validated via several experimental case studies on the two unmanned rotorcraft platforms. The experiments set consists of: trajectory tracking subject to atmospheric disturbances, slung load operations, fast highly disturbed maneuvers, collisions handling, as well as avoidance of known obstacles.
ABSTRACT The objective of this article is the detection of tip-fractures as faults in the normal ... more ABSTRACT The objective of this article is the detection of tip-fractures as faults in the normal operation of an Atomic Force Microscope (AFM), where the system's characteristics (damping, tip-radius) vary. The system is modeled as a vibrating cantilever beam whose deflection can be measured. The measurements are assumed to be corrupted by noise within a priori known magnitude. The certainty sets within which the nominal time-varying parameters of the AFM reside are computed via a variation of an ellipsoidal Set Membership Identification technique. The fault is captured at the time instant of the existence of an outlier-measurement.
The robust stabilization problem of a certain class of nonlinear systems is considered. The under... more The robust stabilization problem of a certain class of nonlinear systems is considered. The underlying assumption is that the model uncertainty satisfies the structural matching conditions. Strict matching conditions are exploited and the effect of the induced input field uncertainty is compensated. The robust stabilization for this class of feedback linearizable systems is attained through an optimal control problem guaranteeing robustness against the uncertainties. The solution is obtained through the solution of an algebraic Riccati equation. Sufficient conditions are provided to establish the robust stability of the system
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