This paper demonstrates the application of a low conservative model predictive control (MPC) scheme based on linear parameter-varying (LPV) models to control a utility scale wind turbine. The main objective of the controller is to allow the wind turbine to extract from the wind a prespecified desired amount of power according to the wind speed and to guarantee the stability of the closed-loop system during the whole range of operation. An LPV representation for a nonlinear model of a 225 KW wind turbine is developed using the Jacobian linearization based technique. A tight parameter set is considered to reduce the conservatism of the LPV model. Then a quasi min-max MPC-LPV algorithm is used to compute online the optimal control input at each sampling instant. The performance and the efficiency of the MPCLPV scheme is validated via simulation and it is compared with another MPC scheme based on linearized models of the system.

This paper demonstrates the application of a low conservative model predictive control (MPC) scheme based on linear parameter-varying (LPV) models to control a utility scale wind turbine. The main objective of the controller is to allow the wind turbine to extract from the wind a prespecified desired amount of power according to the wind speed and to guarantee the stability of the closed-loop system during the whole range of operation. An LPV representation for a nonlinear model of a 225 KW wind turbine is developed using the Jacobian linearization based technique. A tight parameter set is considered to reduce the conservatism of the LPV model. Then a quasi min-max MPC-LPV algorithm is used to compute online the optimal control input at each sampling instant. The performance and the efficiency of the MPCLPV scheme is validated via simulation and it is compared with another MPC scheme based on linearized models of the system.

This paper demonstrates the application of a low conservative model predictive control (MPC) scheme based on linear parameter-varying (LPV) models to control a utility scale wind turbine. The main objective of the controller is to allow the wind turbine to extract from the wind a prespecified desired amount of power according to the wind speed and to guarantee the stability of the closed-loop system during the whole range of operation. An LPV representation for a nonlinear model of a 225 KW wind turbine is developed using the Jacobian linearization based technique. A tight parameter set is considered to reduce the conservatism of the LPV model. Then a quasi min-max MPC-LPV algorithm is used to compute online the optimal control input at each sampling instant. The performance and the efficiency of the MPCLPV scheme is validated via simulation and it is compared with another MPC scheme based on linearized models of the system.

Laboratory evaluation of elastomer- and plastomer-modified asphalt binders using different grades of asphalt binders and produced asphalt concrete mixes is the subject of this paper. The evaluated polymer modifiers in this study were an elastomer [commercially available styrene-butadiene-styrene (SBS) and a plastomer (functionally modified olefin commercially known as Eastman EE-2)], blended separately with two penetration-grade binders (60/70 and 80/100) at polymer/binder ratios of 2%, 4%, and 6% (by mass). The rheological properties of the polymer-modified binders (PMBs) were tested using a rotational viscometer, dynamic shear rheometer, and bending beam rheometer. The effect of the polymers on the rheological properties of the asphalt binders was investigated before and following standardized short- and long-term oxidative aging. Hot-mix asphalt mixes were prepared and evaluated in terms of the number of performance tests, which included indirect tensile strength, moisture susceptibility, resilient modulus, creep-recovery strain properties, and indirect tension fatigue. Analysis of the obtained PMBs indicated that the addition of the elastomer and plastomer polymers to petroleum asphalts was very useful in obtaining a number of desirable characteristics. The main indicators of such improvements are improved rutting resistance of the unaged and short-term aged binders, and the addition of higher percentages of the polymers resulted in an upward shift of the rutting resistance without impacting the fatigue properties of the binders. The addition of up to 6% of the polymers to the binders raised the performance grade (PG) of the PMBs by at least two grades from their base PG. For the softer binder (i.e., Pen. 80/100), 6% SBS pumped the PG of the binder three grades up. The introduction of varying amounts of elastomer and plastomer polymers can significantly influence the resultant mechanistic properties of mixtures.

Active magnetic bearing (AMB) systems have attracted much attention in the high speed rotating machinery industry. This paper presents an application of discrete-time model predictive control (MPC) subject to input/states constraints to control an AMB system based on linear time-invariant (LTI) model. The main control objectives are to levitate the rotor shaft of the AMB system while tracking a reference trajectory and to reject possible disturbances without violating the input and state constraints. A nonlinear (NL) model of the AMB system is considered; at each sampling instant, a finite horizon MPC problem is solved to compute the optimal control input. The performance and the efficiency of the proposed MPC is validated via simulation and comparison with another classical PID controller.

Active magnetic bearing (AMB) systems have attracted much attention in the high speed rotating machinery industry. This paper presents an application of discrete-time model predictive control (MPC) subject to input/states constraints to control an AMB system based on linear time-invariant (LTI) model. The main control objectives are to levitate the rotor shaft of the AMB system while tracking a reference trajectory and to reject possible disturbances without violating the input and state constraints. A nonlinear (NL) model of the AMB system is considered; at each sampling instant, a finite horizon MPC problem is solved to compute the optimal control input. The performance and the efficiency of the proposed MPC is validated via simulation and comparison with another classical PID controller.

Active magnetic bearing (AMB) systems have attracted much attention in the high speed rotating machinery industry. This paper presents an application of discrete-time model predictive control (MPC) subject to input/states constraints to control an AMB system based on linear time-invariant (LTI) model. The main control objectives are to levitate the rotor shaft of the AMB system while tracking a reference trajectory and to reject possible disturbances without violating the input and state constraints. A nonlinear (NL) model of the AMB system is considered; at each sampling instant, a finite horizon MPC problem is solved to compute the optimal control input. The performance and the efficiency of the proposed MPC is validated via simulation and comparison with another classical PID controller.

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Offshore platforms in seismically active areas should be properly designed to survive within the face of intense earthquakes without a global structural collapse. This paper scrutinizes the seismic performance of a newly designed and established jacket type offshore platform based on the API-RP2A normalized response spectra during seismic events. A finite element model is developed from a typical jacket type offshore platform taking into the effect of the interaction among structure, pile, and soil components. The seismic responses of jacket type offshore platforms subjected to random earthquake excitations are evaluated by means of the power spectral density (PSD) analysis. Dynamic characteristics, the response function, output PSD and transfer functions for various elements of the platform are discussed. The spectrum compatible PSD is directly used to estimate the peak structural responses and determine the dynamic response of offshore jacket platforms that meet the required level of engineering practice for preliminary design.