The Experts below are selected from a list of 222 Experts worldwide ranked by ideXlab platform
Baohai Wu - One of the best experts on this subject based on the ideXlab platform.
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an efficient full discretization method for prediction of milling stability
International Journal of Machine Tools & Manufacture, 2012Co-Authors: Dinghua Zhang, Baohai WuAbstract:Abstract This paper presents an efficient full-discretization method for the prediction of milling stability. The dynamic milling process is represented in state-Space form with a single discrete time delay. After discretizing the time period equally into a finite set of intervals, in each small time discretization step, the time-delayed item is first approximated with three neighboring discrete state values, and the time-periodic item is represented by the linear interpolation method. Meanwhile, by utilizing the derivability of the state item and considering the unique structure of the state-Space Equation, the derivatives of the state items at the start and end of each interval could be obtained, with which the state item could then be more precisely and compactly approximated by using Hermite interpolation. Finally, the transition matrix over a single period is determined to predict the milling stability via the Floquet theory. The rate of convergence of the proposed method is estimated and compared with other methods. Two benchmark examples are utilized to verify the effectiveness of the proposed method for the prediction of milling stability both in low and high spindle speed domains. The results show that the proposed method has high computational efficiency.
Hui Zhang - One of the best experts on this subject based on the ideXlab platform.
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Time-varying state observer based twisting control of linear induction motor considering dynamic end effects with unknown load torque
ISA Transactions, 2019Co-Authors: Lei Zhang, Hussein Obeid, Salah Laghrouche, Hui ZhangAbstract:This paper presents a time-varying state observer based twisting control (TC) technique scheme for linear induction motor (LIM) considering dynamic end effects. With Ducan’s T-model, indirect field oriented control strategy is introduced and the state Space Equation of LIM is obtained in (, ) rotary reference frame. On this basis, LIM’s model is extended to two subsystems: flux extended model and speed extended model. Twisting algorithm (TA) is applied into these two subsystems to achieve speed tracking and flux tracking with finite time convergence in the presence of disturbance and uncertainty. For the rotor flux estimation, a time-varying state observer is designed, and its stability and convergence have been proved with Lyapunov’s theory. Moreover, the value of estimated LIM speed derivative is obtained via second order sliding mode observer. Furthermore, a reduced order load torque observer is designed to estimate the external load torque. The feasibility and effectiveness of proposed method has been validated by Hardware-in-the-loop (HIL) test experiment.
Lei Zhang - One of the best experts on this subject based on the ideXlab platform.
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Time-varying state observer based twisting control of linear induction motor considering dynamic end effects with unknown load torque
ISA Transactions, 2019Co-Authors: Lei Zhang, Hussein Obeid, Salah Laghrouche, Hui ZhangAbstract:This paper presents a time-varying state observer based twisting control (TC) technique scheme for linear induction motor (LIM) considering dynamic end effects. With Ducan’s T-model, indirect field oriented control strategy is introduced and the state Space Equation of LIM is obtained in (, ) rotary reference frame. On this basis, LIM’s model is extended to two subsystems: flux extended model and speed extended model. Twisting algorithm (TA) is applied into these two subsystems to achieve speed tracking and flux tracking with finite time convergence in the presence of disturbance and uncertainty. For the rotor flux estimation, a time-varying state observer is designed, and its stability and convergence have been proved with Lyapunov’s theory. Moreover, the value of estimated LIM speed derivative is obtained via second order sliding mode observer. Furthermore, a reduced order load torque observer is designed to estimate the external load torque. The feasibility and effectiveness of proposed method has been validated by Hardware-in-the-loop (HIL) test experiment.
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Nonlinear Feedback Super Twisting Field Oriented Control of Linear Induction Motors Considering Dynamic End Effects
2018 15th International Workshop on Variable Structure Systems (VSS), 2018Co-Authors: Lei Zhang, Hussein Obeid, Salah Laghrouche, Mustapha HamerlainAbstract:This paper proposes a nonlinear feedback super twisting field oriented control (NSTC) technique for linear induction motors (LIMs), taking into consideration the dynamic end effects. The state Space Equation of LIM is given based on Ducan's model. Based on the knowledge of indirect field oriented control (IFOC) theory, a nonlinear feedback super twisting controller is designed to achieve speed and flux tracking, regardless of external disturbances. Simulation results show that the the proposed NSTC scheme has good tracking performance and robustness property with external disturbances.
Salah Laghrouche - One of the best experts on this subject based on the ideXlab platform.
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Super-Twisting Based Fault-Tolerant Control of Multiple-input Three-Phase Interleaved Boost Converter
2020Co-Authors: Xinyang Hao, Salah Laghrouche, Youcef Ait Amirat, Abdesslem DjerdirAbstract:With the drastic inclination towards reduction of atmospheric issues, fuel-cell vehicles are becoming the major alternative for internal combustion. Due to the characteristics of the fuel cell, multiple-input converter is more attractive in redundancy and safety. In this paper, a multi-input three-phase interleaved boost converter (IBC) is designed by analyzing every state of its work to obtain its averaged state-Space Equation. Two control methods based on PI and super-twisting (ST) are designed and applied to the converter. A fault-tolerant method is proposed for the IBC. The simulation results of fault-tolerant based on two control methods are compared. The results show that it has better performance in fluctuation of DC bus voltage and inductor current when using ST method.
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Time-varying state observer based twisting control of linear induction motor considering dynamic end effects with unknown load torque
ISA Transactions, 2019Co-Authors: Lei Zhang, Hussein Obeid, Salah Laghrouche, Hui ZhangAbstract:This paper presents a time-varying state observer based twisting control (TC) technique scheme for linear induction motor (LIM) considering dynamic end effects. With Ducan’s T-model, indirect field oriented control strategy is introduced and the state Space Equation of LIM is obtained in (, ) rotary reference frame. On this basis, LIM’s model is extended to two subsystems: flux extended model and speed extended model. Twisting algorithm (TA) is applied into these two subsystems to achieve speed tracking and flux tracking with finite time convergence in the presence of disturbance and uncertainty. For the rotor flux estimation, a time-varying state observer is designed, and its stability and convergence have been proved with Lyapunov’s theory. Moreover, the value of estimated LIM speed derivative is obtained via second order sliding mode observer. Furthermore, a reduced order load torque observer is designed to estimate the external load torque. The feasibility and effectiveness of proposed method has been validated by Hardware-in-the-loop (HIL) test experiment.
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Nonlinear Feedback Super Twisting Field Oriented Control of Linear Induction Motors Considering Dynamic End Effects
2018 15th International Workshop on Variable Structure Systems (VSS), 2018Co-Authors: Lei Zhang, Hussein Obeid, Salah Laghrouche, Mustapha HamerlainAbstract:This paper proposes a nonlinear feedback super twisting field oriented control (NSTC) technique for linear induction motors (LIMs), taking into consideration the dynamic end effects. The state Space Equation of LIM is given based on Ducan's model. Based on the knowledge of indirect field oriented control (IFOC) theory, a nonlinear feedback super twisting controller is designed to achieve speed and flux tracking, regardless of external disturbances. Simulation results show that the the proposed NSTC scheme has good tracking performance and robustness property with external disturbances.
Ivan D. Remizov - One of the best experts on this subject based on the ideXlab platform.
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Formulas that Represent Cauchy Problem Solution for Momentum and Position Schrödinger Equation
Potential Analysis, 2020Co-Authors: Ivan D. RemizovAbstract:In the paper we derive two formulas representing solutions of Cauchy problem for two Schrödinger Equations: one-dimensional momentum Space Equation with polynomial potential, and multidimensional position Space Equation with locally square integrable potential. The first Equation is a constant coefficients particular case of an evolution Equation with derivatives of arbitrary high order and variable coefficients that do not change over time, this general Equation is solved in the paper. We construct a family of translation operators in the Space of square integrable functions and then use methods of functional analysis based on Chernoff product formula to prove that this family approximates the solution-giving semigroup. This leads us to some formulas that express the solution for Cauchy problem in terms of initial condition and coefficients of the Equations studied.
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Formulas that represent Cauchy problem solution for momentum and position Schr\"{o}dinger Equation
arXiv: Mathematical Physics, 2017Co-Authors: Ivan D. RemizovAbstract:In the paper we derive two formulas representing solutions of Cauchy problem for two Schrodinger Equations: one-dimensional momentum Space Equation with polynomial potential, and multidimensional position Space Equation with locally square integrable potential. The first Equation is a constant coefficients particular case of an evolution Equation with derivatives of arbitrary high order and variable coefficients that do not change over time, this general Equation is solved in the paper. We construct a family of translation operators in the Space of square integrable functions and then use methods of functional analysis based on Chernoff product formula to prove that this family approximates the solution-giving semigroup. This leads us to some formulas that express the solution for Cauchy problem in terms of initial condition and coefficients of the Equations studied.
