基于压电智能结构状态估计误差补偿的自抗扰振动控制

压电智能结构的模型难以精确建立,且存在外界环境激励干扰和内部参数不确定等问题,从而影响闭环结构的振动控制性能。基于此,将结构的内部干扰和外界激励的影响归结为系统的集总干扰,并利用扩张状态观测器(Extended state observer,ESO)设计不依赖于模型的自抗扰振动控制器。然而当外界扰动激励变化时,扩张状态观测器对扰动和各阶状态的估计不可避免存在偏差,难以保证振动控制的效果。为克服二阶自抗扰策略在振动主动控制中的不足,提出一种基于压电智能板结构的状态估计误差补偿自抗扰振动控制方案。利用状态观测误差信息,对二阶自抗扰控制器进行补偿,从而减小ESO对扰动和各阶状态估计的压力,提高振动控制效果。利用dSPACE实时仿真系统,搭建四面固支压电智能板结构的振动主动试验平台。四种干扰激励的试验结果验证该方法的有效性、实用性和强抗干扰能力。     

On the rejection of internal and external disturbances in a wind energy conversion system with direct-driven PMSG

This paper deals with the critical issue in a wind energy conversion system (WECS) based on a direct-driven permanent magnet synchronous generator (PMSG): the rejection of lumped disturbance, including the system uncertainties in the internal dynamics and unknown external forces. To simultaneously track the motor speed in real time and capture the maximum power, a maximum power point tracking strategy is proposed based on active disturbance rejection control (ADRC) theory. In real application, system inertia, drive torque and some other parameters change in a wide range with the variations of disturbances and wind speeds, which substantially degrade the performance of WECS. The ADRC design must incorporate the available model information into an extended state observer (ESO) to compensate the lumped disturbance efficiently. Based on this principle, a model-compensation ADRC is proposed in this paper. Simulation study is conducted to evaluate the performance of the proposed control strategy. It is shown that the effect of lumped disturbance is compensated in a more effective way compared with the traditional ADRC approach.     

Control of unstable processes with time delays via ADRC

Active disturbance rejection control (ADRC) treats the external disturbance and internal uncertainties as a general disturbance, and uses an extended state observer (ESO) to estimate it in real-time and feeds it back in the control loop, thus can achieve good disturbance rejection performance. However, ADRC is not quite suitable for unstable delayed processes due to its inherent structure. In this paper, a two-degree-of-freedom (2DOF) control structure is proposed for unstable time- delayed systems. Set-point tracking and disturbance rejection are separated in this structure and ADRC is solely responsible for disturbance rejection. A method to tune the ADRC parameters using all the information of the system is proposed, and robustness and performance of the proposed method are analyzed. Simulation examples show that 2DOF-ADRC can achieve good tracking and disturbance rejection performance.     

Enhanced extended state observer-based control for systems with mismatched uncertainties and disturbances

This paper presents an enhanced Extended State Observer (ESO)-based control strategy to deal with the disturbance attenuation problem for a class of non integral-chain systems subject to non-linear mismatched uncertainties and external disturbances. The proposed control strategy does not assume the integral-chain form and it is formed by a state-feedback plus a dynamic disturbance compensation term, which is designed to reject the disturbance effect in the system output. From a theoretical point of view, the proposed strategy is reduced to the conventional ESO when the integral chain form and the matched condition hold. In this sense, this paper is presented as an extension of the ESO principles to cover a wider class of systems. The theoretical results show that the internal zero-dynamics plays an important role in ESO-based control design. Also, the closed-loop stability is analyzed and some numerical simulations show the effectiveness of the proposal in comparison with previous ESO-based techniques.     

Tuning of linear active disturbance rejection controller with robustness specification

Active disturbance rejection control (ADRC) treats all the model uncertainties and all the external disturbances as a generalized disturbance. It uses an extended state observer (ESO) to estimate the generalized disturbance in real time, and compensate it using a state-feedback control law, thus can achieve good disturbance rejection performance. For linear ADRC (LADRC), the parameters can be tuned via the bandwidths of the ESO and the feedback control, thus an LADRC can be regarded as a fixed-structured controller with several parameters to tune, just like a PID controller. To help tuning the parameters of LADRC, a tuning rule is proposed in this paper, with the aim to minimize the load disturbance attenuation performance in the integral of time square error sense, under the constraint of a specified robustness measure for the first-order processes with deadtime. The tuning rule is tested for a variety of benchmark systems and the gravity drained tanks case, and the performances are compared with the well-known PID tuning methods.     

基于微分平坦的旋转倒立摆双闭环抗扰 PID 控制

针对一类不稳定、欠驱动二自由度旋转倒立摆系统, 提出一种基于微分平坦的双闭环抗扰 PID 控制方法。 首先, 建立倒 立摆的非线性动力学模型, 利用近似线性化分析系统的不稳定零动态与非最小相位特性; 然后, 结合微分平坦理论, 设计倒立摆 平坦输出,重构系统平坦状态, 并建立平坦状态与角度输出之间的转化关系,克服倒立摆的非最小相位影响; 进一步, 针对微分 平坦系统, 设计抗扰 PID 双闭环控制结构和带宽化调节方法, 在主动抗扰机制下实现对摆杆角度与悬臂角度的精准控制; 最后, 通过仿真与实验, 验证所提方法的有效性和实用性。 所提方法为欠驱动系统提供了一种结构简单、抗扰能力强的控制方案。     

基于滑模和扩张状态观测器的双绕组无轴承磁通 切换电机转子悬浮控制策略研究

双绕组无轴承磁通切换电机是非线性多变量的复杂对象,传统的转速PI与径向位移PI控制存在超调大,系统易受外界扰动影响等缺点。基于滑模变结构控制思想,提出一种转子径向位移滑模控制策略。针对滑模控制中存在建模不准确,以及转子动力学模型中存在陀螺效应等问题,通过建立一种扩张状态观测器对系统扰动进行观测,并在滑模控制基础上加入扰动前馈补偿,设计出一种径向位移滑模控制与扩张状态观测器的复合控制策略。实验结果表明,所提径向位移滑模控制相比传统PI控制具有响应速度快、径向位移脉动小、抗负载扰动性强等优点。所提径向位移滑模与扩张状态观测器的复合控制策略,相比于径向位移滑模控制可有效减小转子径向位移脉动约30%,进一步增强了系统的鲁棒性。     

机带海水冷却电液伺服系统反步抗扰控制研究

针对船舶传动装置机带海水冷却系统的电液伺服系统,通过详细建立阀控液压马达系统的数学模型,提出反步抗扰控制策略。该方法利用反步设计方法将系统分为3个子系统,分别设计相应的控制率;考虑系统中的非匹配干扰和匹配干扰,结合不确定性和干扰估计器以及观测器设计方法,提出一种状态和干扰估计器,估计系统状态、非匹配干扰和匹配干扰,并将估计值带入反步法设计的控制率,获得最终的反步抗扰控制率。分析状态和干扰估计器的稳定性,证明闭环系统跟踪误差最终一致有界。采用PID控制和反步控制作为对比,仿真验证反步抗扰控制的跟踪性能。结果表明:所提出的反步抗扰控制方法具有较强的抗扰鲁棒性,能够有效补偿干扰,进而获得快速准确的跟踪效果。     

混合煤气管道多变量系统自抗扰解耦控制

针对煤气混合蝶阀串联系统具有强耦合、不确定性、干扰因素多、非线性等特点,应用自抗扰控制（ADRC）静态解耦和扩张状态观测器（ESO）动态解耦技术,给出一种适用于煤气混合蝶阀串联系统的ADRC解耦设计方案。为提高系统的响应速度,减少计算量,控制系统去掉跟踪微分器（TD）,并且ESO和NF（非线性反馈）采用线性函数的ADRC。仿真结果表明,该控制方案不仅解耦效果优良,而且具有较好的跟踪性能和抗扰动能力。     

阀控单出杆缸电液伺服系统二阶线性自抗扰控制

为提高阀控单出杆缸电液伺服系统性能,在构建阀控单出杆缸电液伺服系统动态机理模型基础上,提出了一种具有加速度前馈的二阶线性自抗扰控制(Linear Active Disturbance Rejection Control, LADRC)方法,采用奇异摄动理论分析了闭环系统稳定性,并针对系统响应性能和抗干扰性能与传统PID控制进行仿真和实验对比。结果表明:具有加速度前馈的LADRC对系统中存在的多源不确定扰动具有较强鲁棒性,能有效提高系统动、静态性能,并实现对给定信号的快速、精确轨迹跟踪。     

基于ESO的PMSM系统自抗扰FCS-MPC策略

为了提高三相永磁同步电机(PMSM)系统的控制性能,以反双曲正弦函数为基础,通过改进的扩张状态观测器(ESO)获取转速和反电动势项高精度估值,以自抗扰控制作为转速控制调节器,提出了基于ESO的自抗扰有限控制集模型预测控制(FCS-MPC)策略,以减小电磁转矩脉动,降低算法的复杂性和计算量.与基于PI的 FCS-MPC策略相比,新的控制策略能够保证 PMSM系统稳定运行,具有良好的转速跟踪性、抗干扰性和鲁棒性.     

基于自抗扰重复控制的压电驱动器高精度跟踪控制

针对压电驱动器的高精度控制问题,提出一种自抗扰重复控制设计方法。首先,给出压电驱动系统的动力学模型;然后,在线性自抗扰控制(LADRC)中引入输出反馈积分控制器和一类插入式重复控制器,提出一种具有阶跃、斜坡和周期信号跟踪/抑制能力的自抗扰重复控制策略。进一步,结合小增益定理,分析闭环系统的稳定性及控制系统的设计方法。最后,将所提方法应用于一类压电驱动系统,实验结果表明该方法与LADRC相比,能显著提升控制效果,且高精度跟踪/抑制多种外部信号。     

永磁同步电机位置伺服系统改进变结构自抗扰控制

为进一步提高传统变结构自抗扰控制器的控制精度,增强永磁伺服驱动系统的抗干扰能力,提出一种改进变结构自抗 扰控制策略。 该方法在基于变结构原理设计的扩张状态观测器中引入位置、速度的观测误差以实现状态变量的无差估计,采用 基于指数趋近律设计的非线性状态误差反馈控制律实现线性控制与非线性控制的平滑过渡,并在此基础上引入位置跟踪误差, 提高伺服系统的跟踪性能。 通过实验分析比较了改进变结构自抗扰控制与传统变结构自抗扰控制两种控制策略,结果显示改 进控制策略较传统控制策略的位置跟踪误差减少了约 30% 。 当负载突变时,传统控制策略的跟踪误差约为负载突变前最大跟 踪误差的 3. 4 倍,而改进变结构自抗扰控制策略仍能准确跟踪给定信号。     

Active disturbance rejection boundary control of Timoshenko beam with tip mass

In this paper, the active disturbance rejection control (ADRC) is utilized to stabilize the vibration of perturbed Timoshenko beam model with tip mass. The boundary control design is based on a hybrid PDE–ODE model, and is accompanied with designing a high-gain extended state observer (ESO) that is used to estimate the boundary disturbances. By transforming the model into the appropriate state space, the semigroup theory is employed to prove the well-posedness of the closed-loop system. To this end, it is proved by a frequency domain method that the semigroup generated by the system operator is exponentially stable, which allows to conclude the boundedness of perturbed closed-loop system response. The stability of the closed-loop system is further analyzed using the Lyapunov approach. Simulation results are presented to illustrate the efficacy of the suggested method.     

一种提高转矩控制系统性能的新型控制器

在传统异步电机转矩控制策略的基础上,将自抗扰控制器 (ADRC) 的核心环节--扩张的状态观测器 (ESO)引入速度环调节器,构造了一种基于ESO的新型控制器.建立了常规转矩控制系统和采用新型控制器转矩控制系统的仿真模型,并对仿真结果进行分析比较.仿真结果表明,采用新型控制器能有效改善直接转矩控制系统的性能,提高了系统运行的可靠性.新型控制器结构简单,易于实现.     

带ESO的ANFTSMC控制PMSM的新型MPTC无传感器控制策略

针对电动汽车中永磁同步电机传统控制策略对电机控制性能差的问题,提出了一种新型的自适应非奇异快速终端滑模模型预测转矩控制策略.设计了新型自适应指数趋近率,用性质更佳的双曲正切函数tanh()替换传统的切换函数sgn(),并构造了带ESO扰动观测的新型ANFTSMC作为系统转速控制器,消弱了抖振,提高了系统鲁棒性.为实现调速系统的无传感器控制,构造了基于tanh(Fal)的ESO转速观测器.与传统基于Fal函数的ESO相比,观测误差较小,观测精度较高.同时,针对预测转矩控制策略,提出了新型的目标函数构造方法,避免了权重系数的设计,并对传统电压矢量选择方法进行了改进与优化,减少了算法的计算量,结合所设计的新型控制器可有效提高系统的快速性,增加算法的实用性.     

Active disturbance rejection control based human gait tracking for lower extremity rehabilitation exoskeleton

This paper presents an active disturbance rejection control (ADRC) based strategy, which is applied to track the human gait trajectory for a lower limb rehabilitation exoskeleton. The desired human gait trajectory is derived from the Clinical Gait Analysis (CGA). In ADRC, the total external disturbance can be estimated by the extended state observer (ESO) and canceled by the designed control law. The observer bandwidth and the controller bandwidth are determined by the practical principles. We simulated the proposed methodology in MATLAB. The numerical simulation shows the tracking error comparison and the estimated errors of the extended state observer. Two experimental tests were carried out to prove the performance of the algorithm presented in this paper. The experiment results show that the proposed ADRC behaves a better performance than the regular proportional integral derivative (PID) controller. With the proposed ADRC, the rehabilitation system is capable of tracking the target gait more accurately.     

Modified reduced order observer based linear active disturbance rejection control for TITO systems

This paper proposes an observer based control approach for two input and two output (TITO) plant affected by the lumped disturbance which includes the undesirable effect of cross couplings, parametric uncertainties, and external disturbances. A modified reduced order extended state observer (ESO) based active disturbance rejection control (ADRC) is designed to estimate the lumped disturbance actively as an extended state and compensate its effect by adding it to the control. The decoupled mechanism has been used to determine the controller parameters, while the proposed control technique is applied to the TITO coupled plant without using decoupler to show its efficacy. Simulation results show that the proposed design is efficiently able to nullify the interactions within the loops in the multivariable process with better transient performance as compared to the existing proportional-integral-derivative (PID) control methods. An experimental application of two tanks multivariable level control system is investigated to present the validity of proposed scheme.     

Robust current control-based generalized predictive control with sliding mode disturbance compensation for PMSM drives

This paper addresses the current control of permanent magnet synchronous motor (PMSM) for electric drives with model uncertainties and disturbances. A generalized predictive current control method combined with sliding mode disturbance compensation is proposed to satisfy the requirement of fast response and strong robustness. Firstly, according to the generalized predictive control (GPC) theory based on the continuous time model, a predictive current control method is presented without considering the disturbance, which is convenient to be realized in the digital controller. In fact, it's difficult to derive the exact motor model and parameters in the practical system. Thus, a sliding mode disturbance compensation controller is studied to improve the adaptiveness and robustness of the control system. The designed controller attempts to combine the merits of both predictive control and sliding mode control, meanwhile, the controller parameters are easy to be adjusted. Lastly, the proposed controller is tested on an interior PMSM by simulation and experiment, and the results indicate that it has good performance in both current tracking and disturbance rejection.     

Survey on methods of increasing the efficiency of extended state disturbance observers

This survey presents various methods of improving the overall estimation quality in the class of extended state observers (ESO), which estimate not only the conventional states of the system, but the acting disturbance as well. This type of observers is crucial in forming the active disturbance rejection control structure (ADRC), where the precision of online perturbation reconstruction and cancellation directly influences the robustness of the closed-loop control system. Various aspects of the observer-based disturbance estimation/rejection loop are covered by this work and divided into three categories, related with observer: structure, tuning, and working conditions. The survey is dedicated to researchers and practitioners who are interested in increasing the efficiency of their ADRC-based governing schemes.