With the advancement of vehicle-to-vehicle and vehicle-to-infrastructure technologies, more and more real-time information regarding traffic and transportation system will be available to vehicles. This paper presents...
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With the advancement of vehicle-to-vehicle and vehicle-to-infrastructure technologies, more and more real-time information regarding traffic and transportation system will be available to vehicles. This paper presents the development of a novel algorithm that uses available velocity bounds and powertrain information to generate an optimal velocity trajectory over a prediction horizon. When utilised by a vehicle, this optimal velocity trajectory reduces fuel consumption. The objective of this optimisation problem is to reduce dynamic losses, required tractive force, and completing trip distance with a given travel time. sequential quadratic programming method is employed for this nonlinearly constrained optimisation problem. When applied to a GM Volt-2, the generated velocity trajectory saves fuel compared to a real-world drive cycle. The simulation results confirm the fuel consumption reduction with the rule-based mode selection and the energy management strategy of a GM Volt 2 model in Autonomie.
In this study, a combined radial-axial hybrid magnetic bearing (CRAHMB) with four poles is designed for high-speed brushless DC motor. Owing to the small distance of radial and axial unit of CRAHMB, the magnetic flux ...
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In this study, a combined radial-axial hybrid magnetic bearing (CRAHMB) with four poles is designed for high-speed brushless DC motor. Owing to the small distance of radial and axial unit of CRAHMB, the magnetic flux leakage (MFL) in both radial and axial directions is complex and serious. This study focuses on effective analytical model and optimisation of CRAHMB including flux leakage of permanent magnet circuit and control electromagnetic circuit. MFL analytical model was built based on equivalent magnetic circuit method. Under the condition of satisfying the maximum bearing capacity, the MFL coefficients were optimised with sequence quadraticprogrammingmethod. A set of optimum parameters were suggested. MFL before and after optimisation are compared by finite element method. Finally, current stiffness calculated with optimised analytical model was verified on a DC motor experiment. The result shows the accuracies of both the axial and radial current stiffness are enhanced.
Integration between COMSOL Multiphysics (TM) and MATLAB (TM) offers a useful option for the self-automated geometry optimization in proton-exchange membrane fuel cells (PEMFCS). It overcomes the difficulties of automa...
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Integration between COMSOL Multiphysics (TM) and MATLAB (TM) offers a useful option for the self-automated geometry optimization in proton-exchange membrane fuel cells (PEMFCS). It overcomes the difficulties of automatically re-generating high-quality computational meshes and subsequently running the simulations to evaluate the objective function values using commercial software in computational fuel cell dynamics-based designs. Geometry optimization studies of an air-breathing PEMFC searching for the optimum channel ratio at the anode and the optimum open ratio at the cathode, are undertaken. A sequential quadratic programming method is selected to deal with the constrained design problems, while the objective functions are evaluated by running the three-dimensional simulation script of COMSOL (TM) under the MATLAB (TM) environment. Simulation results show that for the air-breathing PEM fuel cell operated at 353 K and one standard atmosphere pressure, when the anode channel ratio is fixed at 10%. the optimum cathode open ratios are very similar for the cell operated at voltages of 0.7 and 0.4V, namely, 49.8% for 0.7 V and 49.5% for 0.4 V. When the cathode open ratio is set at 80% with a cell voltage of 0.7 V, the optimum anode channel ratio is found to be 34.7%. (c) 2008 Elsevier B.V. All rights reserved.
In this study, the dynamics equation of orbital elements without singularities is used to describe the far-distance cooperative rendezvous of two spacecraft with different masses. The convergent costate vector is obta...
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In this study, the dynamics equation of orbital elements without singularities is used to describe the far-distance cooperative rendezvous of two spacecraft with different masses. The convergent costate vector is obtained using the particle swarm optimization with differential evolution (PSODE) hybrid algorithm to optimize the far-distance cooperative rendezvous process of the spacecraft. This vector is then used as the initial value for a sequentialquadraticprogramming (SQP) algorithm to again optimize within a small range to obtain a convergent, stable solution. This study focuses on optimizing the control of the far-distance rapid cooperative rendezvous of spacecraft with different masses and explores the interactions between the magnitude of the thrust, the duration of the rendezvous, and the fuel consumption. Optimization simulation results indicate that when the rendezvous duration is limited to within a certain interval, the optimal process for the rendezvous of spacecraft with different masses is a cooperative manoeuvring type, and an increase in thrust will significantly save fuel. In the case of unrestricted rendezvous duration, as the thrust increases, the rendezvous time decreases, but there is little change in the total fuel consumption. (C) 2015 Elsevier Masson SAS. All rights reserved.
In this paper, we propose a robust sequentialquadraticprogramming (SQP) method for nonlinear programming without using any explicit penalty function and filter. The method embeds the modified QP subproblem proposed ...
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In this paper, we propose a robust sequentialquadraticprogramming (SQP) method for nonlinear programming without using any explicit penalty function and filter. The method embeds the modified QP subproblem proposed by Burke and Han (Math Program 43:277-303, 1989) for the search direction, which overcomes the common difficulty in the traditional SQP methods, namely the inconsistency of the quadraticprogramming subproblems. A non-monotonic technique is employed further in a framework in which the trial point is accepted whenever there is a sufficient relaxed reduction of the objective function or the constraint violation function. A forcing sequence possibly tending to zero is introduced to control the constraint violation dynamically, which is able to prevent the constraint violation from over-relaxing and plays a crucial role in global convergence and the local fast convergence as well. We prove that the method converges globally without the Mangasarian-Fromovitz constraint qualification (MFCQ). In particular, we show that any feasible limit point that satisfies the relaxed constant positive linear dependence constraint qualification is also a Karush-Kuhn-Tucker point. Under the strict MFCQ and the second order sufficient condition, furthermore, we establish the superlinear convergence. Preliminary numerical results show the efficiency of our method.
Successful performance of beam structures is critical to failure prevention, and beam performance can be optimized by careful consideration of beam shape and thickness. Shape and thickness optimization of beam structu...
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Successful performance of beam structures is critical to failure prevention, and beam performance can be optimized by careful consideration of beam shape and thickness. Shape and thickness optimization of beam structures having linear behaviour is treated. The first problem considered is the thickness distribution of the beam where the optimization variable is the thickness of the control points. The second problem is the shape optimization where the optimization variables are the ordinates of the control points. The optimization criterion (function objective to be minimized) is defined starting with the Von Mises criterion expressed in plane constraints. The resolution of the mechanical problem is made by the finite element method, and the optimization algorithm is the sequentialquadraticprogramming (SQP) method.
Conventional foundation bearing capacity calculation is based on Mohr-Coulomb linear failure criterion. But it is verified that almost all kinds of rock's strength envelope is nonlinear with normal stress through ...
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Conventional foundation bearing capacity calculation is based on Mohr-Coulomb linear failure criterion. But it is verified that almost all kinds of rock's strength envelope is nonlinear with normal stress through tests and is in compliance with modified Hoek-Brown nonlinear failure criterion. Therefore, program is composed by using Matlab software and nonlinear sequential quadratic programming method to calculate bearing capacity and analyze its affect factors according to the upper limit theory of limit analysis adopting Hoek-Brown nonlinear failure criterion and multi-tangential method. The result shows that the main affect factors of rock foundation's bearing capacity are GSI and mi of the rock, however, the dead weight γ ,over load q and excavation disturbance coefficient D affect the bearing capacity largely when GSI is small; after comparison with formers’ research, it is found that the bearing capacity is overestimated and having greater risk by using “single-tangential method” while the “mufti-tangential method is more rigorous in theory and whose result is more close to the actual value and more applicable.
Conventional foundation bearing capacity calculation is based on Mohr–Coulomb linear failure criterion. But it is verified that almost all kinds of rock's strength envelope is nonlinear with normal stress through...
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Conventional foundation bearing capacity calculation is based on Mohr–Coulomb linear failure criterion. But it is verified that almost all kinds of rock's strength envelope is nonlinear with normal stress through tests and is in compliance with modified Hoek-Brown nonlinear failure criterion. Therefore, program is composed by using Matlab software and nonlinear sequential quadratic programming method to calculate bearing capacity and analyze its affect factors according to the upper limit theory of limit analysis adopting Hoek-Brown nonlinear failure criterion and multi-tangential method. The result shows that the main affect factors of rock foundation's bearing capacity are GSI and im of the rock, however, the dead weight,over load q and excavation disturbance coefficient D affect the bearing capacity largely when GSI is small;after comparison with formers' research, it is found that the bearing capacity is overestimated and having greater risk by using "single-tangential method" while the "mufti-tangential method is more rigorous in theory and whose result is more close to the actual value and more applicable.
This paper discusses portfolio adjusting problems for an existing portfolio. The returns of risky assets are regarded as fuzzy variables and a class of credibilistic mean-variance adjusting models with transaction cos...
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This paper discusses portfolio adjusting problems for an existing portfolio. The returns of risky assets are regarded as fuzzy variables and a class of credibilistic mean-variance adjusting models with transaction costs are proposed on the basis of credibility theory. Under the assumption that the returns of risky assets are triangular fuzzy variables, the optimization models are converted into crisp forms. Furthermore, we employ the sequential quadratic programming method to work out the optimal strategy. Numerical examples illustrate the effectiveness of the proposed models and the influence of the transaction costs in portfolio selection. (C) 2010 Elsevier B.V. All rights reserved.
In dynamic positioning (DP) systems, 'thrust allocation' is the problem of determining the thrust and direction of each of the 'n' thrusters in an over-actuated offshore vessel from the desired forces ...
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In dynamic positioning (DP) systems, 'thrust allocation' is the problem of determining the thrust and direction of each of the 'n' thrusters in an over-actuated offshore vessel from the desired forces and moment derived in the control law. This is formulated as a non-linear optimisation problem, where the objective is to minimise the use of control effort subject to the constraints, such as actuator rate and power constraints as well as other operational constraints. This paper presents the thrust allocation method for vessels equipped with azimuth thrusters, where the non-linear constrained allocation problem has been solved by the sequentialquadraticprogramming (SQP) method. Simulation results are presented for a semi-submersible, where constraint compliance has been satisfactorily achieved.
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