다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

A new approach to the design of nonlinear disturbance observers (DOBs) for a class of nonlinear systems described by input–output differential equations is presented in this paper. In contrast with established forms of nonlinear DOBs, the most important feature of this new type of DOB is that only measurement of the output variable is required, rather than the state variables. An inverse simulation model is first constructed based on knowledge of the structure and parameters of a conventional model of the system. The disturbance can then be estimated by comparing the output of the inverse model and the input of the original nonlinear system. Mathematical analysis demonstrates the convergence of this new form of nonlinear DOB. The approach has been applied to disturbance estimation for a linear system and a new form of linear DOB has been developed. The differences between the proposed linear DOB and the conventional form of frequency-domain DOB are discussed through a numerical example. Finally, the nonlinear DOB design method is illustrated through an application involving a simulation of a jacketed continuous stirred tank reactor system.

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Disturbance Observer Design for Nonlinear Systems Represented by Input–Output Models

In order to enhance the speed control performance of the permanent magnet synchronous motor (PMSM) with internal and external disturbances, a new adaptive terminal sliding mode reaching law (ATSMRL) is proposed with continuous fast terminal sliding mode control (CFTSMC). Firstly, the ATSMRL is presented with the aim of reducing the input control efforts, which can dynamically adopt all positive aspects in terms of the finite time convergence, high tracking precision, and reduction of the chattering in the control input of the system. Secondly, an extended sliding mode disturbance observer (ESMDO) is designed to estimate the total disturbances of the system, and then the estimated disturbance has been brought for the feed-forward compensation technique, which would enhance the disturbance rejection ability of the system. Afterwards, the close loop stability is validated by the Lyapunov function. Finally the comprehensive numerical and experimental analyses have been carried out to demonstrate the superiority of the ATSMRL method than those of conventional exponential sliding mode reaching law (ESMRL) and terminal sliding mode reaching law (TSMRL).

Adaptive Speed Control of PMSM Drive System Based a New Sliding-Mode Reaching Law

The present draft investigates the finite-time stabilization of T–S fuzzy semi-Markov switching systems by using a coupling memory sampled-data control approach. The main study concerned is how to effectively design the sampled-data control such that closed-loop T–S fuzzy semi-Markov switching systems is finite-time boundedness. By utilizing a Bernoulli distributed sequence, a more general coupling memory fuzzy sampled-data control strategy that involving time delay effect is derived. By virtue of fuzzy-basis-dependent membership functions, an asynchronous approach is proposed for T–S fuzzy semi-Markov switching system. Moreover, the inverted pendulum model is presented to demonstrate the feasibility and validity of the proposed strategies.

Finite-time stabilization of T–S fuzzy semi-Markov switching systems: A coupling memory sampled-data control approach

The main objective of this paper is to solve the position tracking control problem for the permanent magnet linear motor by using the discrete-time fast terminal sliding mode control (SMC) method. Specifically, based on Euler's discretization technique, the approximate discrete-time model is first obtained and analyzed. Then, by introducing a new type of discrete-time fast terminal sliding surface, an improved discrete-time fast SMC method is developed and an equivalent-control-based fast terminal SMC law is subsequently designed. Rigorous analysis is provided to demonstrate that the fast terminal SMC law can offer a higher accuracy than the traditional linear SMC law. Numerical simulations and experimental results are finally performed to demonstrate the effectiveness of the proposed approach and show the advantages of the present discrete-time fast terminal SMC approach over some existing approaches, such as discrete-time linear sliding mode control approach and the PID control method.

Discrete-Time Fast Terminal Sliding Mode Control for Permanent Magnet Linear Motor

In this paper, for the position control problem of permanent magnet linear motors, a fast nonsingular terminal sliding mode control (FNTSMC) method based on the finite-time disturbance observer (FTDO) is proposed. By employing a fast nonsingular terminal sliding surface, the FNTSMC is designed. Besides, a FTDO is applied to estimate the disturbance and the estimation is served as compensation for the controller. A rigorous analysis based on the Lyapunov stability theory is provided to prove that the proposed control method can achieve faster dynamic response characteristic and higher steady accuracy than the linear sliding mode control method and the PID control method. Numerical simulation results are explored to illustrate the superiority of the proposed approach.

Position tracking control for permanent magnet linear motor via fast nonsingular terminal sliding mode control

In this paper, for the position control problem of permanent magnet linear motors, a digital control algorithm based on terminal sliding mode control method is proposed. At the first step, based on Euler's discretization, the approximate discrete-time model is obtained. By introducing a new discrete-time terminal sliding surface, then an improved discrete-time terminal sliding mode control method is designed. By a rigorous stability analysis, it is demonstrated that the improved discrete-time terminal sliding mode control method can offer a higher accuracy than the discrete-time linear sliding mode control method. The comparing simulation results are given to verify the effectiveness of the proposed approach.

Xiuping Chen

Papers

Discrete-Time Fast Terminal Sliding Mode Control for Permanent Magnet Linear Motor

Position tracking control for permanent magnet linear motor via fast nonsingular terminal sliding mode control

Position Tracking Control for Permanent Magnet Linear Motor via Discrete-time Terminal Sliding Mode Control