https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Wed, 11 Mar 2026 09:48:06 GMT 2026-03-11T09:48:06Z http://hdl.handle.net/10985/11599 A reconfigurable damage-tolerant controller based on a modal double-loop framework GENARI, Helói F.G; COFFIGNAL, Gérard; NOBREGA, Euripedes; MECHBAL, Nazih Active vibration control of flexible structures has received considerable attention in the latest decades. However, several related control problems remain open to new investigations such as robust performance, spillover instability, and structural changes due to damage. Specifically in the case of damage, it may significantly aggravate closed-loop performance. Damage-tolerant active control is a recent research area that includes structural damage effect reduction in the controller design requirements. This paper presents a novel control method based on a modal double-loop controller design, aiming for vibration reduction of noncollocated flexible structures subject to damage and encompassing online reconfigurability. The first controller is designed for the healthy system in order to comply with predefined performance and robustness requirements, based on modal H∞H∞ norm. The second controller complements the closed-loop performance if the structure is damaged. A reconfigurable modal technique is adopted to design the second controller, using online modal structural parameter change information to update the controller. To assess the proposed method, finite element models are developed for a case study structure, including health and damage conditions. Results show the effectiveness of the methodology along with performance improvement compared to single-loop controllers based on regular H∞H∞ and modal H∞H∞ approaches. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/11599 2017-01-01T00:00:00Z GENARI, Helói F.G COFFIGNAL, Gérard NOBREGA, Euripedes MECHBAL, Nazih Active vibration control of flexible structures has received considerable attention in the latest decades. However, several related control problems remain open to new investigations such as robust performance, spillover instability, and structural changes due to damage. Specifically in the case of damage, it may significantly aggravate closed-loop performance. Damage-tolerant active control is a recent research area that includes structural damage effect reduction in the controller design requirements. This paper presents a novel control method based on a modal double-loop controller design, aiming for vibration reduction of noncollocated flexible structures subject to damage and encompassing online reconfigurability. The first controller is designed for the healthy system in order to comply with predefined performance and robustness requirements, based on modal H∞H∞ norm. The second controller complements the closed-loop performance if the structure is damaged. A reconfigurable modal technique is adopted to design the second controller, using online modal structural parameter change information to update the controller. To assess the proposed method, finite element models are developed for a case study structure, including health and damage conditions. Results show the effectiveness of the methodology along with performance improvement compared to single-loop controllers based on regular H∞H∞ and modal H∞H∞ approaches. http://hdl.handle.net/10985/11655 A modal H∞-norm-based performance requirement for damage-tolerant active controller design GENARI, Helói F.G; COFFIGNAL, Gérard; NOBREGA, Euripedes; MECHBAL, Nazih Damage-tolerant active control (DTAC) is a recent research area that encompasses control design methodologies resulting from the application of fault-tolerant control methods to vibration control of structures subject to damage. The possibility of damage occurrence is not usually considered in the active vibration control design requirements. Damage changes the structure dynamics, which may produce unexpected modal behavior of the closed-loop system, usually not anticipated by the controller design approaches. A modal H∞H∞ norm and a respective robust controller design framework were recently introduced, and this method is here extended to face a new DTAC strategy implementation. Considering that damage affects each vibration mode differently, this paper adopts the modal H∞H∞ norm to include damage as a design requirement. The basic idea is to create an appropriate energy distribution over the frequency range of interest and respective vibration modes, guaranteeing robustness, damage tolerance, and adequate overall performance, taking into account that it is common to have previous knowledge of the structure regions where damage may occur during its operational life. For this purpose, a structural health monitoring technique is applied to evaluate modal modifications caused by damage. This information is used to create modal weighing matrices, conducting to the modal H∞H∞ controller design. Finite element models are adopted for a case study structure, including different damage severities, in order to validate the proposed control strategy. Results show the effectiveness of the proposed methodology with respect to damage tolerance. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/11655 2017-01-01T00:00:00Z GENARI, Helói F.G COFFIGNAL, Gérard NOBREGA, Euripedes MECHBAL, Nazih Damage-tolerant active control (DTAC) is a recent research area that encompasses control design methodologies resulting from the application of fault-tolerant control methods to vibration control of structures subject to damage. The possibility of damage occurrence is not usually considered in the active vibration control design requirements. Damage changes the structure dynamics, which may produce unexpected modal behavior of the closed-loop system, usually not anticipated by the controller design approaches. A modal H∞H∞ norm and a respective robust controller design framework were recently introduced, and this method is here extended to face a new DTAC strategy implementation. Considering that damage affects each vibration mode differently, this paper adopts the modal H∞H∞ norm to include damage as a design requirement. The basic idea is to create an appropriate energy distribution over the frequency range of interest and respective vibration modes, guaranteeing robustness, damage tolerance, and adequate overall performance, taking into account that it is common to have previous knowledge of the structure regions where damage may occur during its operational life. For this purpose, a structural health monitoring technique is applied to evaluate modal modifications caused by damage. This information is used to create modal weighing matrices, conducting to the modal H∞H∞ controller design. Finite element models are adopted for a case study structure, including different damage severities, in order to validate the proposed control strategy. Results show the effectiveness of the proposed methodology with respect to damage tolerance. http://hdl.handle.net/10985/11654 Damage-tolerant active control using a modal H∞H∞-norm-based methodology GENARI, Helói F.G; COFFIGNAL, Gérard; NOBREGA, Euripedes; MECHBAL, Nazih A new approach for vibration reduction of flexible structures subject to damage is here proposed, based on modal H∞H∞-norm control. Considering that structural damage provokes different effects on each vibration mode, the proposed method concentrates the control action on modes that are indeed suffering the worst damage consequences. For this purpose, a new modal H∞H∞ norm is introduced, weighing each mode according to control design convenience. Based on this norm, a regular H∞H∞ controller design is applied, using the linear matrix inequality approach. Simulated and experimental results show significant advantages of the proposed methodology over the regular H∞H∞ approach, including damage tolerance. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/11654 2017-01-01T00:00:00Z GENARI, Helói F.G COFFIGNAL, Gérard NOBREGA, Euripedes MECHBAL, Nazih A new approach for vibration reduction of flexible structures subject to damage is here proposed, based on modal H∞H∞-norm control. Considering that structural damage provokes different effects on each vibration mode, the proposed method concentrates the control action on modes that are indeed suffering the worst damage consequences. For this purpose, a new modal H∞H∞ norm is introduced, weighing each mode according to control design convenience. Based on this norm, a regular H∞H∞ controller design is applied, using the linear matrix inequality approach. Simulated and experimental results show significant advantages of the proposed methodology over the regular H∞H∞ approach, including damage tolerance.