航空发动机模糊滑模变结构控制研究

针对航空发动机是一个具有时变不确定性的非线性系统,结合模糊控制和滑模变结构控制的特点,提出了一种基于模糊滑模变结构控制的航空发动机控制方法.采用线性滑模面和指数趋近律设计变结构控制器,应用模糊逻辑系统自适应调节切换增益,避免了传统滑模变结构控制系统在到达阶段对不确定性的敏感性,消除了滑模控制中的抖振.通过数字仿真,结果表明所设计的模糊滑模变结构控制器对系统的参数摄动和外部干扰具有不变性,使被控系统在整个控制阶段都具有较强的鲁棒性.     

基于积分滑模和ESO的四旋翼无人机容错控制

针对四旋翼无人机桨叶损伤故障的位置和姿态控制问题,设计一种基于积分滑模法和扩张状态观测器(ESO)的四旋翼无人机主动容错控制系统.建立了执行机构损伤故障下的无人机非线性模型,采用抗干扰能力较强的滑模控制法(SMC)设计姿态内环和位置外环基本控制器;为减小系统的稳态误差,引入积分环节,构造出积分滑模控制器;通过采用边界层方法,抑制滑模控制算法本身的抖振效应;利用ESO实时估计出系统的内、外总扰动和执行机构损伤干扰并对控制量进行补偿.李雅普诺夫稳定理论验证了该控制系统能够快速收敛达到稳定,数值仿真验证了所设计控制系统的有效性和鲁棒性.     

基于A-2-SMC开关磁阻电机直接转矩控制

文中针对开关磁阻电机转矩脉动大及其控制系统难以实现快速精确调速的缺点,提出了一种自适应二阶滑模控制与直接转矩控制相结合的复合控制方案,并对该方案中的自适应二阶滑模控制器进行设计。该控制器采用超螺旋算法,同时对其增益采用自适应调节,克服了传统二阶滑模控制器增益确定依赖于扰动导数界值的缺点。仿真结果表明,文中所采用的控制方案不仅能对电机转速实现快速精确控制,而且能对电机转矩脉动进行有效抑制。     

基于积分滑模控制的飞行器主动容错控制技术研究

基于容错控制和积分滑模控制理论的研究,对飞行器姿态进行控制,使其具有容错性能。飞行器模型考虑一类具有不确定性以及可能存在执行器故障的非线性系统,针对该系统设计积分滑模控制器,使系统即使在执行器故障情况下也能保持较理想的控制特性。同时也对该系统分别设计基于Lyapunov直接法和常规滑模理论的控制器,便于仿真验证中作为比较。在有无执行器故障的情况下,观察3种控制对状态变量的影响效果,比较常规滑模和积分滑模控制下的抖振情况,结果表明积分滑模控制在控制效果和减弱抖振方面表现更好。     

质心不重合的移动机器人自适应滑模轨迹跟踪控制

针对一类质心和几何中心不重合的移动机器人的轨迹追踪问题,结合反演滑模自适应控制算法设计移动机器人轨迹跟踪控制器.首先,设计一种新的变参数滑模趋近律,并基于该趋近律对移动机器人控制器进行设计,使得系统在给定初始误差时移动机器人仍能跟踪目标轨迹.其次,针对一类质心距离已知的情况,基于移动机器人运动学模型,采用反演滑模控制算法对移动机器人的闭环系统控制器进行设计.并在给定系统初始值的情况下,通过选用合适的参数来优化移动机器人控制系统的整体性能,使得控制系统跟踪误差渐近收敛,移动机器人跟踪给定目标轨迹.然后,针对移动机器人质心距离未知的情况,采用反演滑模控制,引入自适应控制算法对未知参数进行估计,设计轨迹跟踪控制器,并通过Lyapunov函数对移动机器人控制系统进行全局稳定性证明.最后,将设计的新型趋近律结合Backstepping控制与自适应控制通过MATLAB仿真进行对比验证,验证了所设计的控制方法的有效性.     

低音速气动弹性机翼的主动控制

基于模糊滑模控制（FSMC）方法研究了低音速机翼颤振的主动控制。提出一种模糊滑模控制方法,主要解决非线性气动弹性的浮沉和俯仰二维机翼的颤振问题。根据气动弹性机翼,设计了滑模面,建立了模糊滑模控制器,控制器能有效抑制颤振。与自适应控制技术相比较,结果显示模糊滑模控制收敛性更好。     

一种基于神经网络的自适应非线性自动舵

针对仅航向角可测量的船舶航向控制系统,提出一种基于神经网络的自适应非线性航向控制器.首先采用神经网络在线逼近系统中的未知项,并设计滑模观测器在线估计艏摇角速度;然后基于动态面控制思想设计非线性观测器-控制器.利用Lyapunov方法证明了误差变量是一致最终有界的.以某自航船模为例仿真,结果表明所提方法鲁棒性好,且操舵合理.     

飞翼无人机的一种鲁棒自适应控制律设计方法

针对飞翼无人机纵向全包线飞行时非线性特性明显和操纵效率变化显著的问题, 采用鲁棒伺服LQR(RSLQR)与L1自适应相结合的综合自适应控制方法(RSLQR-L1), 以C*(加速度、角速率)为被控变量, 设计了飞翼无人机纵向飞行控制系统。结合无人机实际飞行控制品质需求, 采用RSLQR方法, 设计无人机纵向主控制器;在RSLQR控制器的基本结构上扩展设计L1自适应输出反馈补偿控制器。在系统阐述RSLQR-L1综合自适应控制原理和设计方法的基础上, 通过数值仿真验证了控制结构的先进性和鲁棒性, 满足了飞翼无人机的控制要求。     

基于NDO的单向辅助面滑模飞行控制

针对存在建模误差和外界干扰等不确定因素的飞行姿态系统,使用单向辅助面滑模控制与非线性干扰观测器(NDO)相结合的方法设计控制器。采用单向辅助面滑模控制方法设计标称系统控制器,而对于系统中的不确定性和扰动则利用NDO进行逼近,并将NDO的输出用于设计鲁棒补偿控制项,所设计的控制器可以有效削弱抖振且能够显著提高收敛速度。最后通过Lyapunov理论证明了闭环系统的稳定性,仿真结果也体现了良好的控制效果。     

基于自适应PID技术的无尾飞机容错重构控制

无尾飞机是新型飞机的发展方向,与传统的飞机相比,其飞行控制系统更为复杂,故障出现的概率也更大,因此重构控制系统是无尾飞机安全飞行的保障.采用基于自适应PID技术的动态逆控制来研究无尾飞机的重构控制系统,并获得了相应的仿真结果,证实了基于自适应PID技术的动态逆控制对故障具有较好的重构能力,比单独使用动态逆控制更有效.     

控制增益符号已知的MIMO非线性时滞系统自适应控制

针对一类具有死区模型并且控制增益符号已知的不确定多输入多输出非线性时滞系统,基于滑模控制原理提出了一种稳定的自适应神经网络控制方案。该方案通过使用Lyapunov-Krasovskii泛函抵消了因未知时变时滞带来的系统不确定性。通过利用积分型李亚普诺夫函数,并且构造逼近连续函数,闭环系统证明是半全局一致终结有界。仿真结果表明了该方法的有效性。     

基于改进型滑模变结构的TCR型SVC控制策略研究

本文以TCR型SVC为研究对象,应用先进的非线性控制理论来进行控制器设计,以充分挖掘SVC的工作潜能。详细分析了滑模变结构控制的原理、优缺点,并应用趋近率的设计方法推导出基于指数趋近率的控制率,在与PID控制的跟踪效果对比中,显示出优良的快速性和跟踪精度。另外针对滑模变结构控制所固有的抖振现象,本文提出一种改进的滑模变结构控制系统。最后使用Matlab/simulink环境对所使用的方法进行了仿真验证。     

Fuzzy sliding mode control for a class of piezoelectric system with a sliding mode state estimator

A new fuzzy sliding mode hysteresis compensating control strategy for a kind of typical piezoelectric system (PES) is proposed in this paper. Firstly, a typical nonlinear dynamic model of the PES is introduced. In order to compensate the hysteresis of the PES, an ideal linear hysteretic model is introduced by analyzing the characteristic of dynamic hysteretic model. Then, the ideal hysteretic model is transformed into an expected linear model by multiplying a slope conversion factor which can be obtained by experiment. Further, the sliding mode control principle is constructed to calculate the hysteretic compensating control law, which can guarantee the practical hysteretic characteristic to reach the expected linear output feature. Consider the unmeasured hysteresis output of the PES, we further design a sliding mode estimator to estimate the hysteretic part’s output. Finally, we derive the adaptive law of the fuzzy sliding mode controller, and demonstrate its stability through Lyapunov stability theory. The simulation results show the validity of the sliding mode compensator for this kind of nonlinear dynamic model of PES.     

光刻机主从滑模同步控制系统设计

针对光刻机掩模台与工件台的运动同步性问题,采用主从控制结构,设计了滑模同步控制系统.直线电机和音圈电机构成粗动-精动双执行器结构以保证音圈电机不会达到位移饱和.在常规PID控制系统基础上增加了掩模台精动滑模同步控制器.根据扫描周期内掩模台和工件台的运动特点设计了时变滑模面,在同步性要求很高的曝光扫描时间段内逐渐增大时变...     

自适应模糊滑模控制器设计

针对传统滑模控制的抖振问题,利用线性化反馈技术,将模糊自适应和滑模控制相结合,设计一种新型的模糊滑模控制器。通过模糊推理和基于Lyapunov函数的稳定性分析,获得模糊控制规则的自适应律,构成自适应模糊滑模控制器,有效解决了传统滑模控制中,需要确定参数摄动和外部干扰上确界不确定性问题,倒立摆上的运行结果表明该方法的有效性。     

Controller design of variable structure systems with nonlinear sliding surface

A new sliding mode control with a nonlinear time-varying function is presented. In the conventional sliding mode control, the switching surface is a linear time-varying function, and therefore the speed of response is relatively slow. Here the authors present a new method using a nonlinear time-varying sliding surface instead of a linear sliding surface.<>     

Leader‐Following Formation Control of Multiple Robots with Uncertainties through Sliding Mode and Nonlinear Disturbance Observer

This paper presents a control scheme for the leader‐following formation of multiple robots. The control scheme combines the sliding mode control (SMC) method with the nonlinear disturbance observer (NDOB) technique. The formation dynamics suffer from uncertainties because the individual robots are uncertain. Concerning such formation uncertainties, the leader‐following formation dynamics are modeled. Assuming that the formation uncertainties have an unknown boundary, an NDOB‐based observer was designed to estimate the formation uncertainties. A sliding surface containing the observer outputs has been defined. Regarding the sliding surface, an SMC‐based controller was investigated to form uncertain robots. A sufficient condition in the sense of the Lyapunov theory was proven such that the formation system is asymptotically stable. Herein, some comparison results between the sole SMC method and the second‐order SMC method are presented to demonstrate the effectiveness and feasibility of the control scheme for multiple robots in the presence of uncertainties.     

Control of a 2-DOF ultrasonic piezomotor stage for grommet insertion

The treatment of a common disease called “Otitis Media with Effusion (OME)” involves the surgeon inserting a grommet in the eardrum to bypass the Eustachian tube for draining fluid when medication fails. In this paper, a novel device for myringotomy and grommet insertion is first designed and introduced. Due to the advantages of high precision and fast response, a 2-DOF ultrasonic piezomotor (USM) stage is chosen to provide the motion sequences of the device, especially a precise path tracking during the grommet insertion. This paper briefly presents the mechanical design of the device and the configuration and control of the 2-DOF USM stage. The model of the USM consisting of a linear and nonlinear term is built. A PID controller is used as the main controller and tuned with the help of LQR technique. Since there are nonlinear dynamics caused by friction and hysteresis existing in the system, a nonlinear compensation including a sign function and sliding mode control is designed to reject the nonlinearity. Moreover, a decoupling controller is designed to eliminate the coupling effects between the two USM stages. The experimental results show that the LQR-assisted PID controller with compensation can achieve very good system performance and the decoupling controller can further improve the performance.     

Passivity-based fractional-order integral sliding-mode control design for uncertain fractional-order nonlinear systems

This paper concerns with the problem of designing a passivity-based fractional-order (FO) integral sliding mode controller for uncertain FO nonlinear systems. Utilizing the FO calculus, it is showed that the state trajectories of the closed-loop system reach the FO switching manifold in finite time. The control law ensures the asymptotical stability on the sliding surface. A parameter adjustment scheme for FO integral sliding surface is proposed by using the linear matrix inequality (LMI) approach. The proposed controller can be applied to different systems such as chaotic systems. Finally, simulation results are provided to show the effectiveness of the proposed method controlling chaos in FO Chua circuit and FO Van-der-Pol oscillator.     

Indirect sliding mode control based on gray-box identification method for pneumatic artificial muscle

We present an indirect robust nonlinear controller for position-tracking control of a pneumatic artificial muscle (PAMs) testing system. The system modeling is reviewed, for which the existence of uncertain, unknown, and nonlinear terms in the internal dynamics is presented. From the obtained results, an online identification method is proposed for estimation of the internal functions with learning rules designed via a Lyapunov derivative function. A robust nonlinear controller is then designed based on the approximated functions to satisfy the control objective under the sliding mode technique. Appropriate selection of the smooth robust gain and the sliding surface ensures convergence of the tracking error to a desired level of performance. Stability of the closed-loop system is proven through another Lyapunov function. The proposed approach is verified and compared with a conventional proportional–integral–differential (PID) controller, adaptive recurrent neural network (ARNN) controller, and robust nonlinear controller in a real-time system with three different kinds of trajectories and loading. From the comparative experimental results, the effectiveness of the proposed method is confirmed with respect to transient response, steady-state behavior, and loading effect.