224 research outputs found
Command Governor Strategies to increase Safety and Comfort on Aircrafts
No full textThis paper focuses on constrained control problems based on Command Governor (CG) approach. The CG is a device which is added a to a primal compensated system; its action consists in modifying, whenever necessary, the reference signal supplied to the system, in order to enforce prescribed constraints with acceptable tracking performance. Here, we present an application of the CG strategy to a small commercial aircraft. To show the benefits of the proposed constrained control algorithm, numerical simulations are carried out on a linearized model of the aircraft in the neighborhood of an operating flight condition, taking into account typical constraints which the aircraft is subject to satisfy (i.e. angle of attack and angular rates limitations, commands saturation)
Constrained Control Strategies to Improve Safety and Control on Aircrafts
No full textThe present paper explores the possibility of applying to an aircraft a novel constrained control methodology known as the command governor to improve flight safety and comfort. The proposed strategy is based on predictive control ideas and consists of the separate design of two control actions: an inner primal linear controller that guarantees the tracking of the controlled variables in the absence of constraints and an outer nonlinear static device (the command governor) that is compelled to modify, whenever necessary, the reference signals supplied to the inner controller by taking into account the limitations imposed by the aerodynamics, structures, actuators, and onboard comfort requirements. The reference signal modification is accomplished through an online constrained optimization procedure, which embodies the future plant evolution computed along a finite virtual time horizon. Two numerical examples are developed on a high-performance military aircraft and a small commercial aircraf
Constrained control strategies to improve safety and comfort on aircraft
No full textThe present paper explores the possibility of applying to an aircraft a novel constrained control methodology known as the command governor to improve flight safety and comfort. The proposed strategy is based on predictive control ideas and consists of the separate design of two control actions: an inner primal linear controller that guarantees the tracking of the controlled variables in the absence of constraints and an outer nonlinear static device (the command governor) that is compelled to modify, whenever necessary, the reference signals supplied to the inner controller by taking into account the limitations imposed by the aerodynamics, structures, actuators, and onboard comfort requirements. The reference signal modification is accomplished through an online constrained optimization procedure, which embodies the future plant evolution computed along a finite virtual time horizon. Two numerical examples are developed on a high-performance military aircraft and a small commercial aircraft. Copyright © 2008 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved
A command governor approach to plasma shape control
No full textThe paper deals with the application of the socalled Command Governor (CG) approach to the shape control of plasmas in thermonuclear fusion reactors. A primal internal loop controlling the plasma-wall gaps is designed first and a CG device is then tuned to modify, whenever necessary, the reference to the primal loop, taking into account constraints due to voltages saturations on the converters, currents limitations in the active coils, force limits on the mechanical structures, minimum clearance between the plasma and the vacuum chamber wall, maximum induced forces on coils. The reference signal modification is accomplished through an online optimization procedure which embodies plasma model forecasts computed along a finite time virtual receding horizon as usual in model predictive paradigms. The ITER (International Thermonuclear Experimental Reactor) tokamak is assumed as a case study. Numerical simulations are carried out on a numerical nonlinear model taking into account almost a hundred of constraints. ©2009 IEEE
Constrained plasma shape control in ITER
No full textThis paper presents an application of a novel constrained control methodology known as Command Governor (CG) to the shape control of plasmas in thermonuclear fusion reactors. The CG strategy is based on predictive control ideas and consists in modifying, whenever necessary, the reference signal supplied to a primal internal loop controlling the plasma distance from the internal walls of the tokamak, taking into account constraints due to voltages saturations on the converters, currents limitations in the active coils for magnetic confinement, force limits on the mechanical structures, minimum clearance between the plasma and the vacuum chamber wall, maximum induced forces on coils. The reference signal modification is accomplished through an on-line optimization procedure which embodies plasma model forecasts computed along a finite time virtual receding horizon. A numerical example with about a hundred of constraints, is developed with reference to ITER
A Command Governor Approach to Plasma Shape Control
No full textThe paper deals with the application of the socalled Command Governor (CG) approach to the shape control of plasmas in thermonuclear fusion reactors. A primal internal loop controlling the plasma-wall gaps is designed first and a CG device is then tuned to modify, whenever necessary, the reference to the primal loop, taking into account constraints due to voltages saturations on the converters, currents limitations in the active coils, force limits on the mechanical structures, minimum clearance between the plasma and the vacuum chamber wall, maximum induced forces on coils. The reference signal modification is accomplished through an online optimization procedure which embodies plasma model forecasts computed along a finite time virtual receding horizon as usual in model predictive paradigms. The ITER (International Thermonuclear Experimental Reactor) tokamak is assumed as a case study. Numerical simulations are carried out on a numerical nonlinear model taking into account almost a hundred of constraints
A constrained control strategy for the shape control in thermonuclear fusion tokamaks
No full textThe paper deals with the application of the so-called Reference (or Command) Governor constrained control strategy to the shape control of plasmas in thermonuclear fusion reactors with the main scope of optimizing tokamak operations also in conditions very close to the operating envelope limits. A primal inner loop controlling the plasma-wall distance is first designed; the Reference Governor device is then tuned to modify, whenever necessary, the reference signals to the inner loop, on the basis of constraints due to voltage saturations on the power supply converters, limitations of currents in the active control coils, minimum clearance between the plasma surface and the vacuum chamber wall, maximum induced magnetic fields and forces on coils. As usual in model predictive paradigms, the reference signal modification is accomplished through an on-line optimization procedure which embodies plasma model forecasts computed along a finite time virtual receding horizon. The ITER (International Thermonuclear Experimental Reactor) tokamak is assumed as the case study. Numerical simulations are carried out on a finite elements nonlinear model taking into account induced currents in the passive structures. The proposed application shows how almost a hundred constraints can be managed on-line by the Reference Governor. © 2012 Elsevier Ltd. All rights reserved
A hybrid real-time supervisory scheme for nonlinear systems
No full textIn this paper we develop a hybrid supervisory control architecture in a real-time environment for constrained nonlinear systems. The strategy is based on Command Governor (CG) ideas that are here specialized in order to take into account both time-varying set-points and constraints. Experimental results on a laboratory four-tank test-bed are presented. © 2011 AACC American Automatic Control Council
A Hybrid Real-Time Command Governor Supervisory Scheme for Constrained Control Systems
No full textIn this paper, we develop a hybrid supervisory control architecture in a real-time environment for constrained control systems. The strategy is based on Command Governor (CG) ideas that are here specialized to consider both time-varying set-points and constraints. The significance of the method mainly lies on its capability to avoid constraints violation and loss of stability regardless of any configuration change occurrence in the plant/constraint structure by replacing the current CG with a new on-line computed unit. A real-time scheme is an extremely appealing choice because of its numerous engineering applications: automobile industry, defense and aerospace, chemical and nuclear plant applications, multimedia/telecommunications, and so on. Experimental results on a laboratory four-tank test-bed and simulations on a Cessna 182 aircraft model show the effectiveness of the proposed strategy
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