微手系统的鲁棒无源跟踪控制

近年来, 微手系统作为机器人技术的一个热门研究领域, 受到了越来越多的关注. 由于微手系统是复杂且具有非线性的, 因此在实际应用当中很难达到精确跟踪的性能. 为了解决微手系统的精准控制问题, 本文讨论了微手系统的鲁棒无源跟踪控制. 首先, 运用基于演算子理论的鲁棒右互质分解方法, 建立了微手系统的动态模型. 然后, 通过结合无源补偿算子, 设计了无源鲁棒控制器, 保证了系统的鲁棒稳定性和无源性. 进而提出了基于双Bezout恒等式的鲁棒跟踪控制方案, 使整个非线性系统具有较强的鲁棒性和良好的跟踪性能. 最后, 通过仿真进一步验证了所提出方法的有效性     

基于形状记忆合金驱动器的微纳定位系统鲁棒自适应控制

针对基于智能材料驱动器串联驱动的微纳定位系统,本文主要探讨了此类高精定位系统的控制设计策略.其控制设计的主要任务是消除驱动器中未知回滞特性对系统性能所造成的负面影响.本文重点以形状记忆合金驱动器为例,采用基于广义play算子的广义Prandtl-Ishlinskii回滞模型来表征形状记忆合金驱动器中的未知饱和回滞非线性,并在此基础上提出了一种鲁棒自适应控制设计方法来消除前置回滞存在的影响.设计的控制器在保证全局稳定性的基础上能实现理想的跟踪精度,仿真结果验证了控制策略的有效性和正确性.     

基于反步法的直流电机鲁棒速度跟踪控制

为实现具有电枢反应非线性和参数不确定性的直流电机速度跟踪控制,采用自适应反步法,设计了鲁棒自适应速度跟踪控制器.首先推导了电机的非线性动态模型并考虑了电机转动惯量及负载转矩的不确定性,然后经非线性变换并利用线性参考模型导出了系统的误差动态方程,基于自适应反步法设计了鲁棒速度跟踪控制器,最后时其稳定性进行了分析证明.     

一类具有L∞范数有界扰动的非线性系统鲁棒控制

首先针对不确定非线性系统,基于L∞范数定义了鲁棒稳定化和鲁棒跟踪控制问题.然后利用反馈线性化技术和Lvapunov方法,设计了相应的鲁棒控制器.仿真结果验证了控制器设计的正确性.     

高超声速飞行器非线性鲁棒控制律设计

高超声速飞行器具有模型非线性程度高、耦合程度强、参数不确定性大、抗干扰能力弱等特点,其自主控制具有较大的挑战.论文提出了一种基于鲁棒补偿技术和反馈线性化方法的非线性鲁棒控制方法.文中首先采用反馈线性化的方法对纵向模型进行输入输出线性化,实现速度和高度通道的解耦和非线性模型的线性化.针对得到的线性模型,设计包括标称控制器和鲁棒补偿器的线性控制器.基于极点配置原理,设计标称控制器使标称线性系统具有期望的输入输出特性,利用鲁棒补偿器来抑制参数不确定性和外界扰动对于闭环控制系统的影响.基于小增益定理,证明了闭环控制系统的鲁棒稳定性和鲁棒跟踪性能.相比于非线性回路成形控制方法,仿真结果表明了所设计非线性鲁棒控制算法的有效性和优越性.     

直线伺服系统非线性自适应鲁棒控制器优化设计的研究

对永磁直线电动机伺服系统提出非线性自适应鲁棒控制器的优化设计方法。在永磁直线伺服系统非线性数学模型的基础上,为实现对速度和电流的准确跟踪,建立了误差系统的动态模型。将跟踪和干扰抑制归结为非线性自适应鲁棒控制器设计问题,通过构造存储函数得到自适应鲁棒控制器的定理,以及电阻和电感的辨识算法。证明定理给出的控制器能满足干扰抑制和系统的渐近稳定。最后,用遗传算法对控制器的参数进行优化。仿真结果表明,用该方法设计的系统能很好的抑制扰动和跟踪给定,满足对高性能数控机床永磁直线伺服系统控制的要求.     

一类具有L∞ 范数有界扰动的非线性系统鲁棒控制

首先针对不确定非线性系统, 基于 L_∞ 范数定义了鲁棒稳定化和鲁棒跟踪控制问题. 然后利用反馈线性化技术和Lyapunov方法, 设计了相应的鲁棒控制器. 仿真结果验证了控制器设计的正确性.     

襟翼机电作动器的非线性跟踪控制器设计

针对存在未知扰动的民机襟翼机电作动器,为了实现位置跟踪控制,提出了一种新型的非线性连续鲁棒控制器.利用反向递推理论对非线性连续鲁棒控制器进行了设计.首先通过设计电流虚拟控制量,对未知机械扰动进行了补偿;其次,利用电流虚拟控制量,设计了控制电压,实现了对未知扰动信号的抑制.根据李雅普诺夫稳定性分析方法,论证了在所设计的控制器作用下,受控机电作动器能够实现对参考轨迹的全局渐进跟踪.仿真结果表明,改进控制器能够有效提高机电作动器的位置跟踪控制性能,控制效果优于PID控制.     

具有未知干扰的无人机鲁棒滑模飞行控制

研究无人机飞行稳定性控制问题,由于无人机飞行控制系统存在时变外部干扰,飞行过程中升阴比变化激烈,控制稳定性难度较大。利用滑模控制良好的鲁棒能力提出一种神经网络的鲁棒飞行控制方法。因神经网络有良好非线性逼近能力,可对无人机飞行系统中的不确定进行在线逼近,并将神经网络权值误差引入到权值的自适应律中用以改善系统的动态性能。利用神经网络的组合,设计无人机鲁棒滑模飞行控制器。控制器分为两部分,一部分是等效控制器,另一部分是滑模控制器,能有效减小系统的跟踪误差。最后将所设计的鲁棒滑模控制对无人机飞行姿态控制进行仿真。仿真结果表明,新方法能提高无人机的鲁棒飞行控制能力且能实现无人机姿态的精确跟踪和稳定性控制。     

基于自适应动态规划的非线性鲁棒近似最优跟踪控制

为克服现有近似最优跟踪控制方法只能跟踪连续可微参考输入的局限,本文针对一类具有未知动态的连续时间非线性时不变仿射系统,提出了一种新的基于自适应动态规划的鲁棒近似最优跟踪控制方法.首先采用递归神经网络建立系统模型,然后建立评价神经网络对最优性能指标进行估计,从而得到最优性能指标偏导数的估计值,进而得到近似最优跟踪控制器,最后利用系统输出与参考输入之间的跟踪误差设计鲁棒项对神经网络建模误差进行补偿.分别针对两个非线性系统进行仿真实验,仿真结果表明了所提方法的有效性和优越性.     

Operator‐based robust control for nonlinear plants with uncertain non‐symmetric backlash

This paper presents an operator‐based robust nonlinear control method for nonlinear plants with uncertain non‐symmetric backlash. The control design is achieved by introducing operator‐based robust right coprime factorization. In more detail, using an operator‐theoretic approach, the uncertain non‐symmetric backlash is described as a generalized Lipschitz operator and a bounded parasitic term. Since the generalized Lipschitz operator is unknown, a new robust condition using robust right coprime factorization is proposed to guarantee robust stability of the controlled plant with the uncertain backlash. As a result, based on the proposed robust condition, a stabilized plant is obtained. For eliminating the effect from the parasitic term to ensure the output tracking performance, a nonlinear tracking controller is designed. Simulation results are presented to validate the effectiveness of the proposed control design method. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Operator-based nonlinear feedback control design using robust right coprime factorization

In this note, robust stabilization and tracking performance of operator based nonlinear feedback control systems are studied by using robust right coprime factorization. Specifically, a new condition of robust right coprime factorization of nonlinear systems with unknown bounded perturbations is derived. Using the new condition, a broader class of nonlinear plants can be controlled robustly. When the spaces of the nonlinear plant output and the reference input are different, a space change filter is designed, and in this case this note considers tracking controller design using the exponential iteration theorem.     

Robust tracking control for operator-based uncertain micro-hand actuator with Prandtl–Ishlinskii hysteresis

Since the hysteresis property inherently exists in the rubber material, it is necessary to deal with the control issues for the micro-hand by considering the hysteresis property. Therefore, in this paper, the robust tracking control for the micro-hand systems is discussed from the aspect of the Prandtl–Ishlinskii hysteresis property which is more applicable for the real applications. Firstly, a new model is obtained by combining the dynamic model of the micro-hand with Prandtl–Ishlinskii hysteresis property. Secondly, a new stability condition based on bounded input and bounded output stability is proposed for the Prandtl–Ishlinskii hysteresis modeled micro-hand system from two different cases. Thirdly, by designing the robust controllers based on the internal model control method, the tracking performance can be improved by eliminating the effect from the disturbance. Finally, simulation is used to further demonstrate the effectiveness of the proposed design scheme.     

Robust backstepping output tracking control for SISO uncertain nonlinear systems with unknown virtual control coefficients

The output tracking controller design problem is dealt with for a class of nonlinear strict-feedback form systems in the presence of nonlinear uncertainties, external disturbance, unmodelled dynamics and unknown time-varying virtual control coefficients. A new method based on signal compensation is proposed to design a linear time-invariant robust controller, which consists of a nominal controller and a robust compensator. It is shown that the closed-loop control system with a controller designed by the proposed method has robust asymptotical practical tracking property for any bounded initial conditions and robust tracking transient property if all initial states are zero.     

Operator-Based Robust Nonlinear Free Vibration Control of a Flexible Plate With Unknown Input Nonlinearity

In this paper,a robust nonlinear free vibration control design using an operator based robust right coprime factorization approach is considered for a flexible plate with unknown input nonlinearity.With considering the effect of unknown input nonlinearity from the piezoelectric actuator,operator based controllers are designed to guarantee the robust stability of the nonlinear free vibration control system.Simultaneously,for ensuring the desired tracking performance and reducing the effect of unknown input nonlinearity,operator based tracking compensator and estimation structure are given,respectively.Finally,both simulation and experimental results are shown to verify the effectiveness of the proposed control scheme.     

Operator-based robust control design for a human arm-like manipulator with time-varying delay measurements

In this paper, an operator-based robust nonlinear control for a human multi-joint arm-like manipulator with time-varying delay measurements is proposed by using robust right coprime factorization approach, a delay compensation operator and a forward predictive operator. That is, first, considering the uncertainties of dynamic model consisting of measurement error and disturbances, an operator-based nonlinear feedback control scheme is designed to eliminate effect of uncertainties. Second, an operator controller based on real measured data from human multi-joint arm viscoelasticity is presented to obtain desired motion mechanism of human multi-joint arm viscoelastic properties, the unknown time-varying delay measurements are described by a delay operator, the delay compensation operator is designed to remove the effect of unknown time-varying delay measurements, and the forward predictive operator is designed to compensate the term related to effect of central nervous system (CNS) during human multi-joint arm movements. The BIBO stability can be guaranteed and the tracking performance can be realized by the designed operator controller, the delay compensation operator and the forward predictive operator. Finally, the effectiveness of the proposed design scheme is confirmed by the simulation results based on experimental data.     

Robust adaptive tracking control for servo mechanisms with continuous friction compensation

In this paper, a robust adaptive tracking control scheme is developed for servo mechanisms with nonlinear friction dynamics. A continuously differentiable friction model is used to capture the friction behaviors (e.g. Stribeck effect, Coulombic friction and Viscous friction). The robust integral of the sign of the error (RISE) feedback term is employed to design an innovative adaptive controller to compensate nonlinear friction and bounded disturbances. To reduce the effect of noise pollution, the desired trajectory is employed to replace the output signal in controller design. The developed adaptive controller can guarantee the asymptotic tracking performance for nonlinear servo mechanisms in the presence of nonlinear friction and bounded disturbances. Comparative experimental results are used to validate the effectiveness of the developed control algorithm.     

Operator-Based Robust Nonlinear Control for SISO and MIMO Nonlinear Systems With PI Hysteresis

In this paper, operator based robust nonlinear control for single-input single-output (SISO) and multi-input multi-output (MIMO) nonlinear uncertain systems preceded by generalized Prandtl-Ishlinskii (PI) hysteresis is considered respectively. In detail, by using operator based robust right coprime factorization approach, the control system design structures including feedforward and feedback controllers for both SISO and MIMO nonlinear uncertain systems are given, respectively. In which, the controller design includes the information of PI hysteresis and its inverse, and some sufficient conditions for the controllers in both SISO and MIMO systems should be satisfied are also derived respectively. Based on the proposed conditions, influence from hysteresis is rejected, the systems are robustly stable and output tracking performance can be realized. Finally, the effectiveness of the proposed method is confirmed by numerical simulations.      

PI tracking control for nonlinear time-varying delay Markov jump systems

This paper considers robust stochastic stability and PI tracking control problem for Markov jump systems with both input delay and an unknown nonlinear function. Based on the traditional PI control strategy, a new controller design scheme is proposed for nonlinear time-delay Markov jump systems which can realize multiple control objectives including robust stochastic stability and tracking performance. By using the Lyapunov stability theory and LMI algorithms, a sufficient condition for the solution to robust stochastic stability and tracking control problem is obtained. Then, the desired controller with PI structure is designed, which ensures the resulting closed-loop system is robust stochastically stable and the system state has favorable tracking performance. Finally, a numerical example is provided to illustrate the effectiveness of the proposed results.