线性-滑模变结构的IPMSM直接转矩控制研究

为了提高内置式永磁同步电机(IPMSM)直接转矩控制系统的动态品质及鲁棒性,使系统在暂态、稳态过程中具有更优良的特性,提出了将直接转矩控制与线性-滑模变结构控制相结合的策略,分别采用转矩、磁链线性(PI)-滑模控制器取代了传统直接转矩控制中的滞环或PI控制器,该控制器分别根据转矩、磁链给定量与反馈量的误差动态调节平衡增益,使其实现线性控制与滑模开关控制的平衡关系,满足系统的控制需求。理论分析及实验结果表明,这种控制策略可极大地减小了磁链及转矩脉动,增大了调速范围,同时仍保持直接转矩控制固有的转矩快速响应特征,在负载恒定或突变条件下系统具有快速跟踪、鲁棒性强的优点,有效改善了系统的动、静态运行性能。

PMSM的线性-滑模变结构直接转矩控制研究

为了改善永磁同步电机直接转矩控制系统的控制性能,提出将直接转矩控制与线性-滑模变结构控制相结合的策略,分别采用转矩、磁链线性-滑模混合型控制器取代了传统直接转矩控制中的滞环或PI控制器,该控制器通过调节增益实现线性控制与滑模开关控制的平衡关系。仿真及实验结果表明,这种控制策略不仅保留了线性控制响应快的特点,同时使系统具有强的鲁棒性,减小了磁链及转矩脉动,系统的动态、静态品质优良。

SLIDING-MODE CONTROL OF UNOERTAINTY BILINEAR SYSTEM

In this paper,the sliding-mode control of a bilinear system is studied. It improves the dynamicresponse of the closedweloop system around the original point and is rather robust to the bounded disturbance. At last,the model of an ammonia synthesis reactor is adopted to illustrate the phenomenon described.

Design of variable structure controller for uncertain time-delay singular system

To study the approximation theory of real sliding mode and the design of variable structure controller for time-invariant linear uncertain time-delay singular system,the approximation theory of real sliding mode was developed to provide foundation for obtaining sliding mode by equivalent control,and switching functions with integral dynamic compensators and variable structure controllers were designed respectively under two circumstances that the system without uncertain part was stabilized by delay-dependent and delay-independent linear state feedback. The design guarantees the asymptotical stablity of switching manifolds,and the variable structure controllers can force solution trajectory of the system to arrive at the switching manifolds in limited time. A numerical example is given to demonstrate the feasibility and simplicity of the design method.

Serret-Frenet frame based on path following control for underactuated unmanned surface vehicles with dynamic uncertainties

The path following problem for an underactuated unmanned surface vehicle(USV) in the Serret-Frenet frame is addressed. The control system takes account of the uncertain influence induced by model perturbation, external disturbance, etc. By introducing the Serret-Frenet frame and global coordinate transformation, the control problem of underactuated system(a nonlinear system with single-input and ternate-output) is transformed into the control problem of actuated system(a single-input and single-output nonlinear system), which simplifies the controller design. A backstepping adaptive sliding mode controller(BADSMC)is proposed based on backstepping design technique, adaptive method and theory of dynamic slide model control(DSMC). Then, it is proven that the state of closed loop system is globally stabilized to the desired configuration with the proposed controller. Simulation results are presented to illustrate the effectiveness of the proposed controller.

ROBUST SLIDING MODE DECENTRALIZED CONTROL FOR A CLASS OF NONLINEAR INTERCONNECTED LARGE-SCALE SYSTEM WITH NEURAL NETWORKS

A new decentralized robust control method is discussed for a class of nonlinear interconnected largescale system with unknown bounded disturbance and unknown nonlinear function term. A decentralized control law is proposed which combines the approximation method of neural network with sliding mode control. The decentralized controller consists of an equivalent controller and an adaptive sliding mode controller. The sliding mode controller is a robust controller used to reduce the track error of the control system. The neural networks are used to approximate the unknown nonlinear functions, meanwhile the approximation errors of the neural networks are applied to the weight value updated law to improve performance of the system. Finally, an example demonstrates the availability of the decentralized control method.

An adaptive neuro-fuzzy sliding mode controller for MIMO systems with disturbance

This paper introduces the mathematical model of ammonia and urea reactors and suggested three methods for designing a special purpose controller. The first proposed method is Adaptive model predictive controller, the second is Adaptive Neural Network Model Predictive Control, and the third is Adaptive neuro-fuzzy sliding mode controller. These methods are applied to a multivariable nonlinear system as an ammonia–urea reactor system. The main target of these controllers is to achieve stabilization of the outlet concentration of ammonia and urea, a stable reaction rate, an increase in the conversion of carbon monoxide(CO) into carbon dioxide(CO_2) to reduce the pollution effect, and an increase in the ammonia and urea productions, keeping the NH_3/CO_2 ratio equal to 3 to reduce the unreacted CO_2 and NH_3, and the two reactors' temperature in the suitable operating ranges due to the change in reactor parameters or external disturbance. Simulation results of the three controllers are compared. Comparative analysis proves the effectiveness of the suggested Adaptive neurofuzzy sliding mode controller than the two other controllers according to external disturbance and the change of parameters. Moreover, the suggested methods when compared with other controllers in the literature show great success in overcoming the external disturbance and the change of parameters.

Sliding Mode Controller Design for a Class of Nonlinear System

A sliding mode control methodology is presented for nonlinear systems represented by input output models, which does not depend on the state variables. There are two parts in the controller design, one is the sliding controller design and the other is the design of linear feedback system. Simulation results demonstrate the validity of the control scheme.

Sliding mode identifier for parameter uncertain nonlinear dynamic systems with nonlinear input

This paper presents a sliding mode (SM) based identifier to deal with the parameter identification problem for a class of parameter uncertain nonlinear dynamic systems with input nonlinearity. A sliding mode controller (SMC) is used to ensure the global reaching condition of the sliding mode for the nonlinear system; an identifier is designed to identify the uncertain parameter of the nonlinear system. A numerical example is studied to show the feasibility of the SM controller and the asymptotical convergence of the identifier.

Adaptive Backstepping Sliding Mode Control for Nonlinear Systems with Input Saturation

An adaptive backstepping sliding mode control is proposed for a class of uncertain nonlinear systems with input saturation.A command filtered approach is used to prevent input saturation from destroying the adaptive capabilities of neural networks (NNs).The control law and adaptive updating laws of NNs are derived in the sense of Lyapunov function,so the stability can be guaranteed even under the input saturation.The proposed control law is robust against the disturbance,and it can also eliminate the impact of input saturation.Simulation results indicate that the proposed controller has a good performance.

Application of composite nonlinear feedback control approach to linear and nonlinear systems

The objective of this research is to realize a composite nonlinear feedback control approach for a class of linear and nonlinear systems with parallel-distributed compensation along with sliding mode control technique.The proposed composite nonlinear feedback control approach consists of two parts.In a word,the first part provides the stability of the closed-loop system and the fast convergence response,as long as the second one improves transient response.In this research,the genetic algorithm in line with the fuzzy logic is designed to calculate constant controller coefficients and optimize the control effort.The effectiveness of the proposed design is demonstrated by servo position control system and inverted pendulum system with DC motor simulation results.

Terminal Sliding Mode Fuzzy Control Based on Multiple Sliding Surfaces for Nonlinear Ship Autopilot Systems

A terminal sliding mode fuzzy control based on multiple sliding surfaces was proposed for ship course tracking steering, which takes account of rudder characteristics and parameter uncertainty. In order to solve the problem, the controller was designed by employing the universal approximation property of fuzzy logic system, the advantage of Nussbaum function, and using multiple sliding mode control algorithm based on the recursive technique. In the last step of designing, a nonsingular terminal sliding mode was utilized to drive the last state of the system to converge in a finite period of time, and high-order sliding mode control law was designed to eliminate the chattering and make the system robust. The simulation results showed that the controller designed here could track a desired course fast and accurately. It also exhibited strong robustness peculiarly to system, and had better adaptive ability than traditional PID control algorithms.

HP nonlinear guidance law design based on smooth sliding mode control

To eliminate the perturbation of interceptor detection induced by aerodynamic heating,the head pursuit (HP) guidance law for three-dimensional interception was presented. The guidance law positioned the interceptor ahead of the target on its flight trajectory,and the speed of interceptor was required to be lower than that of the target. On the basis of a novel head pursuit three-dimensional guidance model,a nonlinear guidance law was developed based on smooth sliding mode control theory. At the same time,a special observer was designed to estimate the target acceleration,and a numerical example on maneuvering ballistic target interception verified the effectiveness of the presented guidance law.

Study of Comparative Saturated Sliding Mode Control and LQR Controller

The saturation problem is the one of the most common handicaps for applying to real applications, especially the actuator saturation. This paper focuses on the robustness of the sliding mode control （SMC） which incorporates a saturation constraint technique compared to classical linear quadratic regulator （LQR） with saturation. In the first step, the authors present a design methodology of SMC of a class of linear saturated systems. The authors present the structure of the saturation, after that the synthesis of the sliding surface is formulate as a problem of root clustering, which leads to the development of a continuous and non-linear control law that ensures the reaching condition of the sliding mode. The second step is devoted to present briefly the LQR controller technique. Finally, to validate results, the authors demonstrate an example of a quarter of vehicle system.

Adaptive fuzzy sliding mode control for coordinated longitudinal and lateral motions of multiple autonomous vehicles in a platoon

In this paper, the platoon control problem of autonomous vehicles in highway is studied. Since the autonomous vehicles have the characteristics of nonlinearities, external disturbances and strong coupling, a novel adaptive fuzzy sliding coordinated control system is constructed to supervise the longitudinal and lateral motions of autonomous vehicles, in which the fuzzy system is employed to approximate the unknown nonlinear functions. Due to the low sensitivity to disturbances and plant parameter variations, the proposed control approach is an efficient way to handle with the complex dynamic plants operating under un-certainty conditions. The asymptotic stability of adaptive coordinated platoon close-loop control system is verified based on the Lyapunov stability theory. The results indicate that the presented adaptive coordinated platoon control approach can accurately achieve the tracking performance and ensures the stability and riding comfort of autonomous vehicles in a platoon. Finally,simulation test is exploited to demonstrate the effectiveness of the proposed control approach.

An Adaptive Sliding Mode Control of Delta Operator Systems with Input Nonlinearity Containing Unknown Slope Parameters

The problem of observer-based adaptive sliding mode control of delta operator systems with time-varying delays subject to input nonlinearity is investigated. The slope parameters of this nonlinearity are unmeasured. A novel adaptive control law is established such that the sliding surface in the state-estimation space can be reached in a finite time. A delay-dependent sufficient condition for the asymptotic stability of both the error system and the sliding mode dynamics is derived via linear matrix inequality(LMI). Finally, a simulation example is presented to show the validity and advantage of the proposed method.