Bernardo Bahia Monteiro

selected publications

1. SciTech

   Controller Agnostic Design Metrics for Stochastic Disturbance Rejection

   Bernardo Bahia Monteiro, Ilya Kolmanovsky, and Carlos E. S. Cesnik

   In AIAA SCITECH Forum Jan 2024

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   This paper presents a framework to compute the probabilities and the expected frequencies of exceedance of design limits by the outputs and inputs of a linear system driven by Gaussian noise. It is assumed that the system has a second input that can be used for feedback control based on the measurements of one of the outputs. This approach is able to capture the effects of the controller by assuming a shape for the loop sensitivity function, which must respect the Bode integral relation. For illustration, a surrogate model of a supersonic aircraft configuration in the approach-to-land flight phase is considered, and the probabilities and expected frequencies of exceedance of design limits of angle of attack, glideslope deviation, elevator deflection, and elevator deflection rate are calculated. To enable fast and accurate derivative computation for gradient-based optimization, frequently used in large-scale multidisciplinary design optimization (MDO), the derivatives of these quantities with respect to design parameters are derived analytically. They are verified against a finite difference approximation with excellent agreement. A simple optimization problem for designing the sensitivity function is considered and the resulting closed-loop system is analyzed.

   @inproceedings{BahiaMonteiro2024,
     author = {Bahia Monteiro, Bernardo and Kolmanovsky, Ilya and Cesnik, Carlos E. S.},
     booktitle = {AIAA SCITECH Forum},
     month = jan,
     title = {Controller Agnostic Design Metrics for Stochastic Disturbance Rejection},
     year = {2024}
   }

2. RAeS

   Gust Load Metrics for Multidisciplinary Design Optimization Considering Fatigue and Active Control

   Bernardo Bahia Monteiro, Carlos E. S. Cesnik, and Ilya Kolmanovsky

   In Royal Aeronautical Society’s 8th Aircraft Structural Design Conference Oct 2023

   Abs Bib PDF

   This paper presents a new approach for incorporate gust load alleviation (GLA) in the multidisciplinary design optimization (MDO) process. With this approach, closed-loop control considerations are incorporated into the MDO problem formulation through the inclusion of the parameterization of the sensitivity to stress transfer function of the aircraft. The parameters of this function are included as design variables and a constraint based on the Bode integral relation is imposed on it. This approach is control agnostic in the sense that it does not explicitly design a controller or its gains, which can be relegated to a later design phase. Two constraints related to the gust loads are added to the MDO problem: one for peak gust stress, based on the design envelope criterion, and the other for fatigue life under continuous turbulence. While the GLA feedback controller does not need to be designed, the optimizer designs the closed-loop sensitivity function directly. The parameterization of the sensitivity function is chosen to guarantee robustness of the closed-loop system. The use of this new approach is demonstrated by performing multidisciplinary design optimization of a flexible free-flying aircraft model subjected to gust loads. The matrix-free adjoint derivatives are verified against finite differences, and the optimum designs with and without control considerations are compared. The use of the proposed approach was able to reduce the optimal wing mass for the closed-loop design in relation to the open-loop design while still satisfying the other constraints.

   @inproceedings{BahiaMonteiro2023a,
     author = {Bahia Monteiro, Bernardo and Cesnik, Carlos E. S. and Kolmanovsky, Ilya},
     booktitle = {Royal Aeronautical Society’s 8th Aircraft Structural Design Conference},
     title = {Gust Load Metrics for Multidisciplinary Design Optimization Considering Fatigue and Active Control},
     year = {2023},
     month = oct
   }

3. SciTech

   Bi-level Multidisciplinary Design Optimization of a Wing Considering Maneuver Load Alleviation and Flutter

   Bernardo Bahia Monteiro, Alasdair C. Gray, Carlos E. S. Cesnik, and 2 more authors

   In AIAA SCITECH 2023 Forum Oct 2023

   doi:10.2514/6.2023-0728

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   The use of maneuver load alleviation (MLA) in an aircraft can lead to significant performance gains through a decrease in the aircraft’s structural weight and synergies with the aerodynamic design. This paper presents a control agnostic approach for incorporating MLA in the multidisciplinary design optimization (MDO), based on expanding the design space with the addition of control surface deflections during a maneuver as design variables. In order to avoid adding design variables to the overall aircraft optimization problem, a bi-level optimization architecture is employed. The inner problem consists of minimizing the aggregated stresses during a maneuver, which are computed in a beam-based structural model coupled with aerodynamics based on the method of sections. The outer optimization problem is an aircraft range maximization MDO, evaluated on a shell-based structure model coupled with Reynolds-averaged Navier-Stokes aerodynamics. This problem is solved for a clamped wing model, with and without a geometrically non-linear flutter constraint. The inclusion of the flutter constraint is shown to impact the trends in the optimal design.

   @inproceedings{BahiaMonteiro2023,
     doi = {10.2514/6.2023-0728},
     title = {Bi-level Multidisciplinary Design Optimization of a Wing Considering Maneuver Load Alleviation and Flutter},
     author = {Bahia Monteiro, Bernardo and Gray, Alasdair C. and Cesnik, Carlos E. S. and Kolmanovsky, Ilya and Vetrano, Fabio},
     booktitle = {AIAA SCITECH 2023 Forum},
     pages = {0728},
     year = {2023}
   }

4. IFASD

   Gust Load Alleviation Control Related Metric for Multidisciplinary Design Optimization

   Bernardo Bahia Monteiro, Carlos Cesnik, and Ilya Kolmanovsky

   In International Forum on Aeroelasticity and Structural Dynamics Jun 2022

   Abs Bib PDF

   This paper presents a new approach for considering gust load alleviation (GLA) in the multi- disciplinary design optimization (MDO) process. Closed-loop control considerations are incorporated into the MDO problem through the inclusion of the parameterization of the aircraft’s sensitivity function to stress. The parameters of such function are included as design variables and a constraint on its Bode integral relation is imposed. This approach is control agnostic in the sense that it does not explicitly design the controller or its gains, which can be relegated to a later design phase. It consists in the addition of two constraints to the MDO problem: one for peak gust stress, based on the design envelope criterion, and the other for fatigue life. While the GLA feedback controller does not need to be designed, the optimizer designs the closed-loop sensitivity function directly. An additional constraint on the Bode integral relation is used to ensure that the bandwidth of the system is bounded by the current technological limit, while the parameterization of the sensitivity function is chosen to guarantee robustness of the closed-loop system. Finally, the use of this new approach is be demonstrated by performing multidisciplinary design optimization of a flexible free-flying aircraft model subjected to gust loads.

   @inproceedings{BahiaMonteiro2022,
     author = {Bahia Monteiro, Bernardo and Cesnik, Carlos and Kolmanovsky, Ilya},
     year = {2022},
     month = jun,
     booktitle = {International Forum on Aeroelasticity and Structural Dynamics},
     city = {Madrid},
     title = {Gust Load Alleviation Control Related Metric for Multidisciplinary Design Optimization}
   }