Optimizing Control for Rotor Vibration with Magnetorheological Fluid Damper

The aim of this work is to analyze and design a control system for vibration reduction in a rotor system using a shear mode magnetorheological fluid(MRF)damper.A dynamic model of the MRF damper-rotor system was built and simulated in Matlab/Simulink to analyze the rotor vibration characteristics and the vibration reduction effect of the MRF damper.Based on the numerical simulation analysis,an optimizing control strategy using pattern search method was proposed and designed.The control system was constructed on a test rotor bench and experiment validations on the effectiveness of the proposed control strategy were conducted.Experimental results show that rotor vibration caused by unbalance can be well controlled whether in resonance region(70%)or in non-resonance region(30%).An irregular vibration amplitude jump can be suppressed with the optimization strategy.Furthermore,it is found that the rapidity of transient response and efficiency of optimizing technique depend on the pattern search step.The presented strategies and control system can be extended to multi-span(more than two or three spans)rotor system.It provides a powerful technical support for the extension and application in target and control for shafting vibration.

A DERIVATIVE-FREE ALGORITHM FOR UNCONSTRAINED OPTIMIZATION

In this paper a hybrid algorithm which combines the pattern search method and the genetic algorithm for unconstrained optimization is presented. The algorithm is a deterministic pattern search algorithm,but in the search step of pattern search algorithm,the trial points are produced by a way like the genetic algorithm. At each iterate, by reduplication,crossover and mutation, a finite set of points can be used. In theory,the algorithm is globally convergent. The most stir is the numerical results showing that it can find the global minimizer for some problems ,which other pattern search algorithms don＇t bear.

Structural Optimization of Concrete Slab Frame Bridges Considering Investment Cost

The present study investigates computer-antomated design and structural optimization of concrete slab frame bridges considering investment cost based on a complete 3D model. Thus, a computer code with several modules has been developed to produce parametric models of slab frame bridges. Design loads and load combinations are based on the Eurocode design standard and the Swedish design standard for bridges. The necessary reinforcement diagrams to satisfy the ultimate and serviceability limit states, including fatigue checks for the whole bridge, are calculated according to the aforementioned standards. Optimization techniques based on the genetic algorithm and the pattern search method are applied. A case study is presented to highlight the efficiency of the applied optimization algorithms. This methodology has been applied in the design process for the time-effective, material-efficient, and optimal design of concrete slab frame bridges.

General Pattern and Neighborhood Search Algorithms for Non-Convex Unit Commitment

This paper presents a new approach to solve mixed-variable unit commitment(UC) problems with non-smooth cost functions based on a generalized pattern search filter(GPS-filter) algorithm. A GPS-filter algorithm does not require any information about the gradient of the objective function while searching for an optimum solution. At the same time, it is available for solving mixed-variable optimization problems, which is very suitable for UC. A new suitable discrete neighborhood structure with UC characteristics is proposed to improve GPS-filter efficiently. A lot of multiple units' states are fixed before search; hence, the polling search of discrete variable is efficient for a few uncertain units. Numerical experiments are included to demonstrate the proposed approach's ability to handle the highly nonlinear, discontinuous, non-smooth cost functions and mixed variables of the UC problem.

Optimal proportion of wind and PV capacity in provincial power systems based on bilevel optimization algorithm under low-carbon economy

In order to boost contributions of power systems to a low-carbon economy,the installed capacity of renewable power generation,such as wind and photovoltaic(PV)power generation should be well planned.A bilevel formulation is presented to optimize the proportion of wind and PV capacity in provincial power systems,in which,carbon emissions of generator units and features of renewable resources are taken into account.In the lowerlevel formulation,a time-sequence production simulation(TSPS)model that is suitable for actual power system has been adopted.In order to maximize benefits of energy conservation and emissions reduction resulting from renewable power generation,the commercial software called General Algebraic Modeling System(GAMS)is employed to optimize the annual operation of the power system.In the upper-level formulation,the optimal pattern search(OPS)algorithm is utilized to optimize the proportion of wind and PV capacity.The objective of the upper-level formulation is to maximize benefits of energy conservation and carbon emissions reductions optimized in the lowerlevel problem.Simulation results in practical provincial power systems validate the proposed model and corresponding solving algorithms.The optimization results can provide support to policy makers to make the polices related to renewable energy.

Design optimization of the APF DTL in the SSC-linac

A linear accelerator as a new injector for the SSC （Separated Sector Cyclotron） of the HIRFL （Heavy Ion Research Facility Lanzhou） is being designed. The DTL （Drift-Tube-Linac） has been designed to accelerate ^238U^34＋ from 0.140 MeV/u to 0.97 MeV/u. To the first accelerating tank which accelerates ^238U^34＋ to 0.54 MeV/u, the approach of Alternating-Phase-Focusing （APF） is applied. The phase array is obtained by coupling optimization software Dakota and beam optics code LINREV. With the hybrid of Multi- objective Genetic Algorithm （MOGA） and a pattern search method, an optimum array of asynchronous phases is determined. The final growth, both transversely and longitudinally, can meet the design requirements. In this paper, the deign optimization of the APF DTL is presented.