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Item type:Publication, Access status: with files , Partial pole placement using static output feedbackFor many dynamical systems it is required to specifically shift individual poles, especially when these poles are lightly damped or even unstable. To achieve that, a preferably large number of effectors and measurements are installed leading to multivariable control problems. In this paper, a novel control approach is presented for placing either a single pole or a conjugate complex pole pair at a predefined location using rank-one static output feedback. Rank-one feedback can be interpreted as blending inputs and outputs to define a single input and single output loop with a desirable root locus along which the pole is moved. The corresponding controller synthesis is reduced to an unconstrained optimization problem in a single variable that aims at minimizing the feedback gain. Although the approach is derived for a single pole or conjugate complex pole pair, it is easily extended to multiple poles. To this end, a repeated design and superposition of rank-one feedback gains is proposed. It is further shown how residual system dynamics as well as subsequently designed gains can be efficiently decoupled from each other in order to avoid undesired interactions and spillover effects. The effectiveness of the proposed control approach is demonstrated by means of a numerical example.Publicationtype: Journal ArticleScopus© Citations 1 87 248 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Robust autopilot design for landing a large civil aircraft in crosswind(2018-07); ; ; A comprehensive autolanding design for a representative model of a twin-engined commercial aircraft is presented in this paper. To facilitate the design task and minimize control law switching, a cascaded control structure is selected which resembles integrator chains. Classical loopshaping and robust control techniques are used to design the individual control loops. The emphasis is on providing a complete and comprehensive qualitative design strategy. The control system's ability to safely land the aircraft despite strong crosswind in a variety of possible scenarios is demonstrated in an industry-grade verification campaign. Nonlinear Monte Carlo simulations of the airliner model are used to assess the risk of unsafe landing conditions and provide insight into the performance characteristics and limitations of the proposed control system.Publicationtype: Journal Article178 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Robust autopilot design for crosswind landingA comprehensive autolanding design for the representative model of a twin-engined commercial aircraft is presented in this paper. A cascaded structure is selected to facilitate the design task and to minimize control law switching. Classical loopshaping and robust control techniques are used to design the individual control loops. The emphasis is on design parameters with a clear relation to design objectives, resulting in an intuitive tuning procedure. The control system's ability to safely land the aircraft despite strong crosswind in a variety of possible scenarios is demonstrated in an industry-grade verification campaign. Monte Carlo simulations are used to assess the risk of unsafe landing conditions and provide insight into the performance characteristics and limitations of the proposed control system.Publicationtype: Journal ArticleScopus© Citations 12 164 689 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Multivariable controller design verification for a liberty wind turbine(2017); The increasing size of modern wind turbines goes hand in hand with an increase of the structural loads on the turbine caused by effects turbulences. Consequently, the use of advanced control algorithms for active load reduction has become a relevant part of current wind turbine control systems. Recently, an H∞-norm optimal multivariable individual blade-pitch controller was designed for the utility scale 2.5 MW Liberty C96 research turbine of the University of Minnesota. In this paper, the controller is evaluated in an extensive industrygrade verification campaign. The campaign includes a large number of simulations in different wind speeds. Damage equivalent loads on the rotating and non-rotating parts of the turbine are calculated to quantify the loads acting on the turbine. The proposed multivariable controller is compared to the Liberty C96’s baseline controller without individual blade-pitch control and a state-of-practice integral individual blade-pitch control law.Publicationtype: Conference Paper67 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Load reduction on a clipper liberty wind turbine with linear parameter-varying individiual blade pitch controlThe increasing size of modern wind turbines also increases the structural loads caused by effects such as turbulence orasymmetries in the inflowing wind field. Consequently, the use of advanced control algorithms for active load reductionhas become a relevant part of current wind turbine control systems. In this paper, an individual blade pitch control law isdesigned using multivariable linear parameter-varying control techniques. It reduces the structural loads both on the rotatingand non-rotating parts of the turbine. Classical individual blade pitch control strategies rely on single-control loops withlow bandwidth. The proposed approach makes it possible to use a higher bandwidth since it accounts for coupling at higherfrequencies. A controller is designed for the utility-scale 2.5 MW Liberty research turbine operated by the University ofMinnesota. Stability and performance are verified using the high-fidelity nonlinear simulation and baseline controllers thatwere directly obtained from the manufacturerPublicationtype: Journal Article16 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Robust control design for load reduction on a liberty wind turbine(American Society of Mechanical Engineers (ASME), 2016-10); ; The increasing size of modern wind turbines also increases the structural loads on the turbine caused by effects like turbulence or asymmetries in the inflowing wind field. Consequently, the use of advanced control algorithms for active load reduction has become a relevant part of current wind turbine control systems. In this paper, an H∞-norm optimal multivariable control design approach for an individual blade-pitch control law is presented. It reduces the structural loads both on the rotating and non-rotating parts of the turbine. Classical individual blade-pitch control strategies rely on single control loops with low bandwidth. The proposed approach makes it possible to use a higher bandwidth since it takes into account coupling at higher frequencies. A controller is designed for the utility-scale 2.5 MW Liberty research turbine operated by the University of Minnesota. Stability and performance are verified using a high-fidelity nonlinear benchmark model.Publicationtype: Conference Paper22