基于跟踪微分器的离散滑模控制器

利用跟踪微分器设计了一种新的离散滑模控制器,可以从不连续的指令信号中合理提取连续信号及微分信号,且不需要利用线性外推的方法预测指令信号下一时刻的值及其微分．与基于趋近律的离散滑模控制器进行的对比仿真表明,所设计的控制器在保持传统滑模控制固有强鲁棒性的同时,控制器的输出几乎不存在抖振现象,而且在跟踪不连续的指令信号时,系统表现出良好的动态品质．

     

基于离散模糊滑模的飞行器角度跟踪控制

为解决某型飞行器的角度跟踪控制问题,设计了离散模糊滑模角度跟踪控制算法.以飞行器在空间的姿态运动方程为基础建立了其短周期运动模型.基于离散时间模糊滑模算法,设计了双入双出的模糊控制器,将滑模切换函数及其变化率作为模糊控制器的输入,以模糊控制器的二维输出信号为依据调整滑模趋近律的参数,该算法在减小了系统的抖振同时,保持了...     

基于非线性参数的电液伺服系统滑模控制

针对在电液伺服系统跟踪控制中存在非线性不确定参数和外界扰动的问题,提出了一种基于积分微分器的滑模Lyapunov函数的控制方法。首先,在只有位移信号测量输出的情况下,采用高阶积分链式微分器对其速度和加速度信息进行预估。系统存在非线性不确定参数,利用微分器对状态和不确定项的实时估计,设计出积分滑模控制器,实现自适应规律以及对电液伺服系统中不确定扰动的抑制。搭建电液伺服系统AMESim模型并与Matlab构成联合仿真平台,对控制器进行仿真。仿真表明,该控制器具有良好的对非线性不确定参数变化的补偿能力和跟踪性能。     

不确定离散系统自适应趋近律滑模控制技术研究

针对受噪声干扰的含有未知参数的离散系统控制问题,首先利用强跟踪滤波器对未知参数进行估计,接着提出了一种自适应离散趋近律滑模控制方法．深入研究分析了该离散趋近律方法的抖振问题,设计了基于该新型趋近律的滑模控制器．仿真结果表明所设计的控制器能有效降低抖振,改善控制性能．     

动态滑模控制在EAF电极调节系统中的应用

针对电弧炉电极调节系统的非线性、时变、模型不确定、大滞后等特点,结合高阶滑模和动态滑模控制的设计思想为其设计了一种动态滑模控制器,即通过微分环节构成新的切换函数,将不连续项转移到控制的一阶中,得到本质连续的动态滑模控制律,并将其应用到电弧炉电极调节系统中。对系统的阶跃响应和跟踪特性分别进行了仿真,仿真结果表明,所设计的动态滑模控制器不仅能使系统具有良好的动态性能和较强的跟踪特性,同时能有效地抑制系统的抖振,达到控制系统的动态品质要求。     

四旋翼无人机轨迹稳定跟踪控制

针对四旋翼无人机轨迹稳定跟踪控制问题,为抑制外界扰动和参数不确定性的影响,设计一种双环鲁棒控制系统.首先,基于动态面内模法设计输出调节器进行位置控制,可解决系统的渐近跟踪及干扰抑制问题;其次,利用高阶滑模设计姿态控制器,可实现全局有限时间收敛,消除系统抖振和相对阶的限制;再次,为进一步提高控制精度,采用一种鲁棒精确微分器对姿态角指令信号进行精确求导;最后,对系统稳定性进行严格的数学证明,并与PID控制和传统滑模控制进行仿真对比,结果验证了所提出控制策略的优越性和鲁棒性.     

基于模糊变结构的机械臂控制

现有的机械臂模糊变结构控制方法大都计算复杂或需要检测滑模面的微分信号.本文将机械臂模型分为确定部分和不确定部分进行研究,对确定部分采用一般反馈控制,对不确定部分采用变结构集中补偿控制,为了消除变结构控制器的抖震引入模糊控制方法,将滑模面作为模糊控制器的输入,补偿控制器权值作为输出.本方案不仅不需要检测滑模面微分信号,而且计算简单,易于实现.仿真结果表明,在存在模型误差和外部扰动的情况下,该方案既能达到快速跟踪,又能很好的消除控制器的抖震.     

基于离散滑模预测的欠驱动AUV三维航迹跟踪控制

针对欠驱动自主水下航行器（AUV）的模型不确定和外界海流干扰问题,为了实现欠驱动AUV的三维航迹跟踪控制,采用虚拟向导法建立空间运动误差离散化模型.基于递归滑模思想设计离散滑模预测控制器,利用滚动优化和反馈校正方法补偿了不确定项对滑模预测模型的影响.最后针对某欠驱动AUV进行了空间曲线跟踪控制仿真实验.结果表明,所设计的控制器可以较好地克服时变非线性水动力阻尼对系统的影响,并对外界海流干扰有较好的抑制作用,保证了欠驱动AUV三维航迹跟踪系统的鲁棒性,实现了三维航迹的精确跟踪.     

基于准连续高阶滑模的可重复使用运载器再入姿态控制

针对可重复使用运载器再入段的姿态控制问题,提出一种基于准连续高阶滑模的控制方法。将姿态控制系统分为两个回路,分别为角度控制回路与角速度控制回路。角度回路作为外回路产生角速度指令,角速度回路作为内回路跟踪外回路产生的角速度控制指令。为了提高系统的鲁棒性,对两个回路分别设计滑模控制器。外回路中设计基于低通滤波的终端滑模控制方法,以获得平滑的控制量作为角速度指令。内回路设计增加系统相对阶的准连续高阶滑模方法,使控制律中不直接含有符号函数项,保证系统稳定的同时减弱控制器抖振。在具有外界干扰与参数不确定的情况下,使用本文提出的方法进行仿真试验,仿真结果证明了所提出方法的有效性。     

球形机器人的建模与控制研究

设计了一种通过三个惯性轮驱动的球形机器人,基于角动量守恒定律实现机器人移动。利用四元数及Kane方程建模方法,建立了球形机器人的完整动力学模型,给出了控制其运动的微分方程组,进而设计一个自适应模糊滑模变结构控制器,以实现对参数及动力学模型不精确的球形机器人的位置控制。为了减弱系统的抖振,通过对滑模控制器中的切换项进行模糊逼近,使切换项连续化。轨迹跟踪的仿真和试验表明,该控制器在参数不确定和动力学模型不精确的系统中有良好的表现。     

On discrete-time variable structure sliding mode control

The purpose of this paper is to show the limitations of discrete-time variable structure sliding mode control and that the equivalent control must be used in order to have sliding in a neighborhood of the switching surface. Conflicting requirements for the sliding mode controller behavior in the continuous and discrete-time domains are revealed and analyzed. A linear control law for an uncertain discrete-time linear plant, with bounded uncertainties, is analyzed and its superiority over nonlinear controllers is demonstrated. The conclusion of the obtained results is that in the discrete-time variable structure sliding mode controller design, unlike in the continuous-time, the designer may have limited flexibility in selecting controller architectures.     

Adaptive sliding mode control for discrete-time multi-input multi-output systems

In this paper, robust adaptive sliding mode tracking control for discrete-time multi-input multi-output systems with unknown parameters and disturbance is considered. The robust tracking controller is comprised of adaptive control and sliding mode control design. Bounded motion of the system around the sliding surface and stability of the global system in the sense that all signals remain bounded are guaranteed. If the disturbance and the reference signal are slowly varying with respect to the sampling frequency, the proposed sliding mode controller can reject the disturbance and output tracking can be approximately achieved. Simulation results are presented to illustrate the proposed approach.     

A new discrete-time sliding-mode control with time-varying gain and neural identification

In this paper, we present a new sliding mode controller for a class of unknown non-linear discrete-time systems. We make the following two modifications. (1) The neural identifier which is used to estimate the unknown non-linear system uses the projection and the dead-zone approaches to assure non-singularity in the controller and stability of identification error. (2) We propose a new sliding mode controller with time-varying gain to reduce chattering. A necessary condition is given to make the switching function decrease exponentially. We prove that the closed-loop system with the sliding mode controller and the neural identifier is stable.     

基于干扰补偿趋近律的离散滑模多周期重复控制

针对离散时间系统的多周期干扰抑制问题,提出一种离散滑模多周期重复控制器设计方法.利用非线性幂次函数设计新型离散趋近律,将周期差分等效干扰以加权形式嵌入到趋近律中,构造带干扰补偿作用的离散趋近律,并据此设计离散滑模多周期重复控制器.为了进行控制器参数整定和表征闭环系统的收敛性能,推导准滑模域边界层的表达式.所提出控制方法既能够消除多周期干扰信号,也能够减小准滑模域边界层.数值仿真验证了所提出控制方法的有效性.     

Discrete-time sliding mode control of flexible rotor-magnetic bearing systems

This paper is concerned with the computer-based sliding mode control of flexible rotor—magnetic bearing systems (FR-MBS). The plant dynamics consisting of actuator dynamics and flexible rotor dynamics are described. The reduced-order model for controller design is given by eliminating higher-order modes of the mechanical and electrical magnetic interaction system. A discrete-time sliding mode controller with a new robust reduced-order variable structure system (VSS) observer is proposed and its robust performance is evaluated with several simulations based on a calculation model. This digital controller is implemented to replace a linear analogue PID compensator. Levitation tests using the proposed digital controller are performed and compared with those of the PID compensator. The unstable modes can be easily controlled with the good stability and the spillover phenomena due to ignored higher-order modes are not generated. It is indicated that the discrete-time sliding mode control has robustness to the model parameter variations and external disturbances. Using the discrete time sliding mode controller with the reduced-order VSS observer, the test rig of the magnetic bearing system can be successfully rotated in a speed range of 0–35 000 rpm, which includes the first critical shaft frequency of the flexible rotor.     

建筑结构基于RBF神经网络的离散滑模控制研究

抖振问题是离散滑模控制在实际系统中应用的突出障碍.根据神经网络控制的优点,采用一种基于RBF神经网络的离散滑模控制方法对地震作用下建筑结构的振动控制问题进行了研究.根据离散系统建模技术,得到了离散时间形式的状态方程,同时给出了确定切换面的方法,并推导了控制律的表达式.以一个三层剪切型建筑结构模型为例来验证所提出的离散滑模控制方法的有效性.算例分析结果表明:本文所提出的控制方法能够有效地减小结构的地震峰值响应,同时达到了削弱控制系统抖振的目的.     

Reaching law for DSMC systems with relative degree 2 switching variable

This paper presents the first attempt to design a reaching law-based discrete-time sliding mode controller with a relative degree 2 switching variable. The current value of this variable is only affected by the control signal and disturbance generated two time instants ago. It is demonstrated that the new reaching law-based strategy offers a smaller quasi-sliding mode band width when compared to a similar control scheme with relative degree 1 switching variable. This in turn leads to reduced system output error in the control system proposed in the paper.     

Fuzzy Sliding Mode Control for Active Suspension System with Proportional Differential Sliding Mode Observer

In this paper, a generalized augmented transformation is considered for the quarter active suspension system with uncertainties. Specifically, the model uncertainties are converted to the augmented states and a new proportion differential sliding mode observer is used to estimate state variables and model uncertainties. A differential geometric method is applied to linearize the nonlinear suspension model. In order to weaken the vibration effect of sliding mode control force and reduce energy consumption, a fuzzy sliding mode controller is designed for the active suspension system and the fuzzy controller is applied to adjust switching control gain according to the reaching condition of sliding mode surface. The simulations are conducted to illustrate the effectiveness and advantages of this proposed observer and control strategy.     

用于离散滑模重复控制的新型趋近律

针对不确定离散时间系统, 提出一种新型的离散趋近律, 构造理想切换动态, 并基于理想切换动态设计离散滑模重复控制器. 在消除系统颤振的同时, 完全抑制周期扰动带来的影响, 改善控制品质. 分别推导了切换函数的绝对收敛层、单调收敛层和拟滑模带的边界, 用于刻画在不同控制器参数下闭环系统的趋近过程和拟滑模运动. 数值仿真和在伺服装置上的实验结果证实了所提出控制方法的有效性.