基于扩张状态观测器的非线性变结构控制器研究

本文针对极点配置法扩张状态观测器ESO的不足,充分利用系统已知信息设计出一种新型ESO,并将其与变结构控制理论相结合,提出一种非线性鲁棒变结构控制器的设计方法,克服了基于反馈线性化理论的非线性控制因数学模型的误差而影响控制器性能的缺点。仿真结果表明所设计的非线性鲁棒变结构控制器对于对象模型参数摄动和外扰具有良好的适应性和鲁棒性。     

基于鲁棒积分的四旋翼飞行器姿态控制

针对四旋翼飞行器姿态控制过程中广泛存在的外部干扰和参数不确定性,提出了一种基于鲁棒符号误差积分(RISE)的四旋翼姿态控制策略。通过一个模型前馈控制项实现精确的模型补偿,抵消模型非线性影响,以及一个鲁棒积分反馈项,有效抑制系统模型不确定性。设计的控制器在参数不确定性、外部干扰、噪声存在的情况下,实现了四旋翼飞行器精确姿态跟踪。基于Lyapunov理论的稳定性分析验证了所设计控制器的收敛性。最后设计大量仿真和对比试验说明该姿态控制方法的有效性和鲁棒性。     

直流微电网内DC/DC变换器非线性控制策略研究

针对直流微电网内储能DC/DC变换器的非线性特性和输出电压扰动较大等问题。基于精确反馈线性化理论提出一种新颖的非线性级联控制器。在所提出的控制策略中,外部电压采用鲁棒性强的PI控制器,内部电流环采用非线性控制。在此基础上,对所提出的级联控制器策略进行Matlab/Simulink仿真,实验结果表明,所提方法具有良好的动态响应和鲁棒特性,在负载出现波动的情况下输出母线电压仍能保持恒定运行,并极大地提高了直流微电网内储能变换器的抗干扰能力。     

DI/QFT控制器在四旋翼无人直升机飞行控制中的应用

首先建立了四旋翼无人机的非线性数学模型.然后针对该无人机数学模型的不确定性和非线性,采用动态逆(DI)和定量反馈理论(QFT)相结合的方法设计了该无人机姿态回路的鲁棒控制器.应用动态逆方法处理对象的非线性,将系统等效为一个解耦但存在不确定性的线性对象.鉴于动态逆控制在气动参数摄动的情况下不能满足控制要求的事实,设计了QFT控制器,QFT控制器能克服对象的参数不确定性,保障系统的鲁棒性.仿真结果表明,在气动数据变化±20%的范围内,DI/QFT控制器实现了对姿态角的精确控制.     

高超声速滑翔式BTT导弹鲁棒反演控制器设计

综合考虑高超声速滑翔式BTT导弹各种干扰的影响,建立了具有非匹配不确定性的非线性、强耦合姿态运动方程,并转化为标准形式。针对模型中的未知不确定性,提出了鲁棒估计函数,利用反演控制和自适应控制设计了高超声速导弹的自动驾驶仪,解决了由于对期望虚拟控制量进行求导产生的“计算膨胀”问题,证明了每一步反演设计的Lyapunov稳定性,并进行了数字仿真。仿真结果表明,所设计的自适应反演控制器能够精确跟踪姿态角指令,并对大范围气动参数摄动具有很强的鲁棒性。     

空间机器人全局逼近收敛控制

针对自由漂浮空间机器人系统,设计了一种全局逼近收敛控制器,解决了存在初始状态误差及外界干扰条件下的系统鲁棒性问题。首先,根据空间机器人系统的状态空间方程设计控制器,该控制器将控制输出特性与控制增益隔离开,对系统模型的不确定性及外界干扰具有强鲁棒性。另外,该控制方法避免了类似反演控制方法带来的复杂度高的问题。其次,从理论上证明了该控制器能够实现机器人系统对期望路径的跟踪。最后,针对单臂六自由度空间机器人系统,分别使用该控制器与鲁棒补偿控制器进行了仿真分析。仿真结果证实了该控制器的强鲁棒性。     

一种基于周期平稳的鲁棒盲神经网络波束形成器

本文提出了一种鲁棒的盲神经网络波束形成算法。该算法利用信号的周期平稳特性估计阵列的导引矢量,利用LCMV方法抑制噪声干扰,利用对角加载技术增强算法的鲁棒性,利用神经网络的网状计算结构特点便于其实现。理论分析和计算机仿真表明,该算法实现简单,鲁棒性强,易于实时应用。     

一类时滞不确定非线性系统的自适应鲁棒H∞控制

本文针对一类同时具有未知上界时滞不确定性和外部扰动的非线性系统，在非线性H∞控制的理论框架内讨论了系统的自适应鲁棒H∞控制问题，通过自适应律估计时滞不确定性的上界，并且基于Lyapunov-Krasovskii函数和Hamilton-Jacobi不等式获得使鲁棒控制问题可解的自适应鲁棒控制器。     

压电定位系统的自耦PID控制

针对一类存在非线性迟滞特性的纳米定位压电驱动器的控制问题,使用了一种与被控系统无关的自耦比例积分微分(ACPID)控制方法。该方法将系统内部所有复杂因素及外部扰动定义为一个总扰动,建立了以总扰动为激励的受控误差系统,进而设计了基于ACPID控制理论的压电定位控制系统。理论分析了ACPID控制系统的鲁棒稳定性和抗扰动鲁棒性。仿真结果表明,ACPID控制系统的有效性不仅具有更快的响应速度、更高的控制精度,且具有良好的抗扰动鲁棒性,在压电定位系统控制领域具有较大应用价值。     

基于非线性系统描述的超声马达鲁棒跟踪控制

针对行波型超声马达,在非线性系统描述的数学模型基础上,采用了一种新的鲁棒控制方案．该控制器由标称控制器和鲁棒补偿器两部分构成。首先,针对标称系统设计标称控制器得到期望的输出跟踪特性,然后加上鲁棒补偿器,实现鲁棒特性。可以证明,鲁棒稳定性、鲁棒静态特性、鲁棒瞬态特性以及鲁棒跟踪特性可同时得到．仿真和实验结果都表明了控制方案的有效性,而且该控制器结构简单、参数可在线调整.     

PID-type sliding mode-based adaptive motion control of a 2-DOF piezoelectric ultrasonic motor driven stage

This paper presents a new scheme of adaptive sliding mode control (ASMC) for a piezoelectric ultrasonic motor driven X–Y stage to meet the demand of precision motion tracking while addressing the problems of unknown nonlinear friction and model uncertainties. The system model with Coulomb friction and unilateral coupling effect is first investigated. Then the controller is designed with adaptive laws synthesized to obtain the unknown model parameters for handling parametric uncertainties and offsetting friction force. The robust control term acts as a high gain feedback control to make the output track the desired trajectory fast for guaranteed robust performance. Based on a PID-type sliding mode, the control scheme has a simple structure to be implemented and the control parameters can be easily tuned. Theoretical stability analysis of the proposed novel ASMC is accomplished using a Lyapunov framework. Furthermore, the proposed control scheme is applied to an X–Y stage and the results prove that the proposed control method is effective in achieving excellent tracking performance.     

压电陶瓷驱动微进给刀架的迟滞建模

以对称式微位移缩小机构和柔性铰链相结合,压电陶瓷驱动的微进给刀架可实现精密加工,但刀架的迟滞特性影响其定位精度。该文根据非线性Preisach模型的理论知识及压电陶瓷驱动微进给刀架的电压位移特性,将模型进行修改后得到刀架迟滞特性的数学模型,并对数学模型式进行离散化处理。实验结果表明,改进后的迟滞模型形式简单,数据采集简便,模型描述精确,能较好地实现压电驱动微进给刀架的迟滞建模,提高了迟滞模型的实用性。为提高压电陶瓷驱动微进给刀架的定位精度,实现精密控制打下基础。     

基于D/A集成控制的压电陶瓷驱动电源设计

压电陶瓷驱动电源是纳米级工作台系统的关键部件。文章提出了采用多级驱动的电源结构，并在此基础上开发研制了基于D／A集成的单片机控制压电陶瓷驱动电源，该电源由多级数控可调直流电压源串联构成，采用具有过载保护的三端可调稳压集成模块LM317作为稳压核心元件。所设计电源分辨率高，响应速度快，驱动能力强，结构简单，调试方便，适用于压电陶瓷驱动器。     

Robust motion controller design for high-accuracy positioningsystems

This paper presents a controller structure for robust high speed and accuracy motion control systems. The overall control system consists of four elements: a friction compensator; a disturbance observer for the velocity loop; a position loop feedback controller; and a feedforward controller acting on the desired output. A parameter estimation technique coupled with friction compensation is used as the first step in the design process. The friction compensator is based on the experimental friction model and it compensates for unmodeled nonlinear friction. Stability of the closed-loop is provided by the feedback controller. The robust feedback controller based on the disturbance observer compensates for external disturbances and plant uncertainties. Precise tracking is achieved by the zero phase error tracking controller. Experimental results are presented to demonstrate performance improvement obtained by each element in the proposed robust control structure     

一类非均匀采样非线性系统的无模型自适应控制

对一类未知的非均匀采样离散时间非线性非仿射系统,基于在受控系统当前工作点处的等价数据模型,利用输入输出数据对伪雅可比矩阵（PJM）的在线估计,设计出相应的无模型自适应控制器.所提出的控制方法具有如下特点：控制器的设计仅需要非均匀采样的输入输出数据,不包含系统模型的任何信息;控制算法计算量小,算法容易实现.最后,通过一个非均匀采样离散时间非线性系统仿真结果验证提出方法的有效性.     

Robust cerebellar model articulation controller design for unknown nonlinear systems

In this study, a robust cerebellar model articulation controller (RCMAC) is designed for unknown nonlinear systems. The RCMAC is comprised of a cerebellar model articulation controller (CMAC) and a robust controller. The CMAC is utilized to approximate an ideal controller, and the weights of the CMAC are on-line tuned by the derived adaptive law based on the Lyapunov sense. The robust controller is designed to guarantee a specified H/sup /spl infin// robust tracking performance. In the RCMAC design, the sliding-mode control method is utilized to derive the control law, so that the developed control scheme has more robustness against the uncertainty and approximation error. Finally, the proposed RCMAC is applied to control a chaotic circuit. Simulation results demonstrate that the proposed control scheme can achieve favorable tracking performance with unknown the controlled system dynamics.     

Inversion-free force tracking control of piezoelectric actuators using fast finite-time integral terminal sliding-mode

The major hurdles to control the force created by piezoelectric actuators (PEAs) are originated from its strong nonlinear behaviors which include hysteresis, creep, and vibration dynamics. To achieve an accurate, fast and robust force tracking performance without using complicated modeling and parameter identification of PEAs, this paper presents a practical direct force control scheme. The proposed controller is based on two core approaches: 1) fast finite-time integral terminal sliding mode (FFI-TSM) which allows fast convergence and high accuracy to the closed-loop system without control chattering; and 2) an inverse-model-free compensation, named force-based time-delayed estimation (FBTDE) which offers significant robustness with minimum use of plant dynamics information. The finite-time stability of the overall closed-loop system is proven through the Lyapunov’s method. The proposed force tracking controller is implemented on the PEA system driving a variable physical damping actuator mechanism. The overall accuracy, convergence speed, and robustness of the proposed controller are validated under various experimental scenarios. Comparative experimental results are particularly presented to verify the effectiveness of the FFI-TSM term and the FBTDE term.     

基于压电驱动的靶球筛选操作机理及实验研究

针对惯性约束聚变中靶球筛选操作的粘着问题,提出一种基于压电驱动控制的微操作方法,并结合微机电系统(MEMS)技术和微驱动方法,研制压电驱动操作模块用于实验研究.首先,分析微尺度对象粘着机理并进行粘着接触模型的建立,并在此基础上提出对操作工具施加振动,利用惯性力作用克服粘着力的动态操作方法;同时,结合靶球筛选操作的特点,分析操作控制策略;最后建立了基于压电驱动的微操作实验系统.针对直径Φ50～400 μm的靶球对象进行操作实验,成功实现了靶球样品的高效、准确拾取和释放,拾取和释放成功率大于90％.     

Bang-bang impact control using hybrid impedance/time-delay control

For stabilization of a robot manipulator upon collision with a stiff environment, a nonlinear bang-bang impact controller is developed. Under this control, a robot can successfully achieve contact tasks without changing the control algorithm or controller gains throughout all three modes: free space, transition and constrained motion. It uses a robust hybrid impedance/time-delay control algorithm to first absorb impact forces and stabilize the system. This control input alternates with zero when no environment force is sensed due to loss of contact. This alternation of control action repeats until the impact transient subsides and steady state is attained. After impact transient, the hybrid impedance/time-delay control algorithm is again utilized. This bang-bang control method provides stable interaction between a robot with severe nonlinear joint friction and a stiff environment, and achieves rapid response while minimizing force overshoots. During contact transition, we employ one simple control algorithm that switches only to zero and maintains the same gains, while other controllers use more than one control algorithm or different control gains. It is shown via experiments that overall performance is superior or comparable to more complicated existing impact force control techniques.     

A robust distributed controller of a single-link SCARA⧹Cartesian smart materials robot

In this paper, dynamic modelling and controller design are presented for a SCARA⧹Cartesian smart materials robot, a flexible SCARA⧹Cartesian robot bonded with piezoelectric actuators and sensors for better control performance. Conventionally, controller design is usually carried out for a truncated model of partial differential equations (PDEs). In this paper, a novel distributed controller is developed directly based on PDEs, which can guarantee the globally exponential stability of the closed-loop system. Taking into account of bounded disturbances, a robust distributed controller is further developed and stability proof is also given. Different from the conventional approach, truncation is introduced at the stage of the controller implementation. Stability proofs show that the proposed controller can also stabilize the finite dimensional model with arbitrary number of flexible modes. Both simulation and experiment results verify that the robust controller can achieve good performance in the suppression of residual vibrations under the environment of disturbances.