共查询到19条相似文献,搜索用时 890 毫秒
1.
2.
3.
4.
5.
针对离散线性时滞系统,设计了最优滑模面和最优离散变结构控制律.在设计最优滑模面的过程中,利用逐次逼近算法,将既含有时滞项又含有超前项的两点边值问题转化为不含时滞项和超前项的线性两点边值问题,并证明了其解序列一致收敛于原系统的最优滑模.进一步给出了原系统的变结构控制律. 相似文献
6.
7.
针对高速信号不确定滑模变结构控制系统的抖振问题,提出一种基于Delta算子离散化方法的不确定Delta算子系统的滑模变结构控制器。基于反正切函数给出了一种改进的Delta算子离散趋近律,将系统的不确定部分用其上、下确界代替,然后设计滑模变结构控制律。仿真结果表明了该方法的可行性和有效性,对内部参数摄动和外部干扰具有良好的完全鲁棒性。因此,基于该趋近律方法设计的滑模变结构控制系统既能在有限时间内快速趋近切换面,又最终稳定于平衡状态。 相似文献
8.
为了提高传统二阶终端滑模控制的全局收敛性,提出一种快速二阶终端滑模控制算法.设计一种二阶趋近律,将绝对值函数隐藏在积分项里,并增加线性项以提高全局收敛性.当系统状态未到达滑模面时,采用二阶趋近律,并通过调整参数避免奇异问题;当系统状态到达滑模面时,采用不含不连续符号项的指数趋近律,以保证控制误差有限时间收敛.采用Lyapunov直接法证明快速二阶终端滑模控制算法的稳定性,及其比super twisting算法具有更优良的收敛特性.以下肢外骨骼为研究对象,建立动力学模型.在考虑建模误差和外部干扰的情况下,将该算法应用于下肢外骨骼的姿态控制.仿真结果表明,所提出的控制算法能够有效抑制抖振,并且比super twisting算法具有更良好的跟踪性能,验证了该算法的有效性. 相似文献
9.
针对一类变时滞离散系统,基于一种新型的非线性时变准滑模面设计方案,研究了系统的鲁棒滑模控制问题.首先,给出了该种非线性切换函数的一般形式,该类准滑模面具有时变的特征,且能够动态地改善系统的运动品质.利用自由权矩阵与线性矩阵不等式技术,给出了该类时滞离散系统非线性准滑模面的设计方法,并得到了稳定的非线性准滑模面存在的充分条件;其次,基于一种改进的离散趋近律方法,设计了相应的准滑模控制器,以保证系统的状态在有限时间内到达准滑模,从而将此类非线性系统的滑模变结构控制的分析与综合问题推广到了时滞非线性系统.最后,仿真结果表明,在本文所设计的准滑模面与准滑模变结构控制器的作用下,系统的状态是稳定的,且具有响应速度快、超调量小、调节时间较小等优点,从而说明了本文所设计方法的有效性. 相似文献
10.
11.
Two approximation laws of sliding mode for discrete-time variable structure control systems are proposed to overcome the limitations of the exponential approximation law and the variable rate approximation law. By applying the proposed approximation laws of sliding mode to discrete-time variable structure control systems, the stability of origin can be guaranteed, and the chattering along the switching surface caused by discrete-time variable structure control can be restrained effectively. In designing of approximation laws, the problem that the system control input is restricted is also considered, which is very important in practical systems. Finally a simulation example shows the effectiveness of the two approximation laws proposed. 相似文献
12.
Two approximation laws of sliding mode for discrete-time variable structure control systems are proposed to overcome the limitations of the exponential approximation law and the variable rate approximation law. By applying the proposed approximation laws of sliding mode to discrete-time variable structure control systems, the stability of origin can be guaranteed, and the chattering along the switching surface caused by discrete-time variable structure control can be restrained effectively. In designing of approximation laws, the problem that the system control input is restricted is also considered, which is very important in practical systems. Finally a simulation example shows the effectiveness of the two approximation laws proposed. 相似文献
13.
针对一类离散时间系统,提出一种变结构控制设计方法。为了减小离散指数趋近律的抖振现象,本文构造一种趋近律, 利用它设计变结构控制器,能够大幅度削弱抖振,有效地改善控制品质,使系统最终趋于原点,并使系统稳定。给出数值计算和仿真算例。 相似文献
14.
A new variable structure control algorithm based on sliding mode prediction for a class of discrete-time nonlinear systems is presented. By employing a special model to predict future sliding mode value, and combining feedback correction and receding horizon optimization methods which are extensively applied on predictive control strategy, a discrete-time variable structure control law is constructed. The closed-loop systems are proved to have robustness to uncertainties with unspecified boundaries. Numerical simulation and pendulum experiment results illustrate that the closed-loop systems possess desired performance, such as strong robustness, fast convergence and chattering elimination. 相似文献
15.
On discrete-time variable structure sliding mode control 总被引:1,自引:0,他引:1
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. 相似文献
16.
17.
针对不确定离散时间系统,提出一种基于离散复合非线性反馈的积分滑模(DCNF-ISM)控制策略,并将该算法应用于扰动下的磁盘跟踪问题.该算法由离散复合非线性反馈(DCNF)控制律与积分滑模(ISM)控制律两部分组成,其中DCNF控制律用于保证系统具有较好瞬态性能,基于改进的离散趋近律设计的ISM控制律用于保证系统鲁棒性.基于Lyapunov稳定性理论对本文提出的控制策略的稳定性进行了推导证明,证明了离散时间系统的一致最终有界性.仿真结果表明,本文提出的控制策略能保证系统在扰动下仍然能够精确跟踪给定的参考信号,与传统的DCNF控制相比,该算法能够保证系统具有响应速度快超调量小、鲁棒性强等优点. 相似文献
18.
19.
A binary available bit rate (ABR) scheme based on discrete-time variable structure control (DVSC) theory is proposed to solve the problem of asynchronous transfer mode (ATM) networks congestion in this paper. A discrete-time system model with uncertainty is introduced to depict the time-varying ATM networks. Based on the system model, an asymptotically stable sliding surface is designed by linear matrix inequality (LMI). In addition, a novel discrete-time reaching law that can obviously reduce chatter is also put forward. The proposed discrete-time variable structure controller can effectively constrain the oscillation of allowed cell rate (ACR) and the queue length in a router. Moreover, the controller is self-adaptive against the uncertainty in the system. Simulations are done in different scenarios. The results demonstrate that the controller has better stability and robustness than the traditional binary flow controller, so it is good for adequately exerting the simplicity of binary flow control mechanisms. 相似文献