An extended state observer with adjustable bandwidth for measurement noise

In this paper,a bandwidth-adjustable extended state observer(ABESO)is proposed for the systems with measurement noise.It is known that increasing the bandwidth of the observer improves the tracking speed but tolerates noise,which conflicts with observation accuracy.Therefore,we introduce a bandwidth scaling factor such that ABESO is formulated to a 2-degree-of-freedom system.The observer gain is determined and the bandwidth scaling factor adjusts the bandwidth according to the tracking error.When the tracking error decreases,the bandwidth decreases to suppress the noise,otherwise the bandwidth does not change.It is proven that the error dynamics are bounded and converge in finite time.The relationship between the upper bound of the estimation error and the scaling factor is given.When the scaling factor is less than 1,the ABESO has higher estimation accuracy than the linear extended state observer(LESO).Simulations of an uncertain nonlinear system with compound disturbances show that the proposed ABESO can successfully estimate the total disturbance in noisy environments.The mean error of total disturbance of ABESO is 15.28% lower than that of LESO.

Civil aircraft fault tolerant attitude tracking based on extended state observers and nonlinear dynamic inversion

For the problem of sensor faults and actuator faults in aircraft attitude control,this paper proposes a fault tolerant control(FTC)scheme based on extended state observer(ESO)and nonlinear dynamic inversion(NDI).First,two ESOs are designed to estimate sensor faults and actuator faults respectively.Second,the angular rate signal is reconstructed according to the estimation of sensor faults.Third,in angular rate loop,NDI is designed based on reconstruction of angular rate signals and estimation of actuator faults.The FTC scheme proposed in this paper is testified through numerical simulations.The results show that it is feasible and has good fault tolerant ability.

Differential geometric guidance command with finite time convergence using extended state observer

For improving the performance of differential geometric guidance command(DGGC), a new formation of this guidance law is proposed, which can guarantee the finite time convergence(FTC) of the line of sight(LOS) rate to zero or its neighborhood against maneuvering targets in three-dimensional(3D) space. The extended state observer(ESO) is employed to estimate the target acceleration, which makes the new DGGC more applicable to practical interception scenarios. Finally, the effectiveness of this newly proposed guidance command is demonstrated by the numerical simulation results.

Extended state observer based smooth switching control for tilt-rotor aircraft

A tilt-rotor aircraft has three flight modes: helicopter mode, airplane mode and conversion mode. Unlike the traditional aircraft, the tilt-rotor aircraft, which combines the characteristics of helicopters and fixed-wing aircraft, is a complex multi-body system with the violent variation of the aerodynamic parameters. For these characteristics, a new smooth switching control scheme is provided for the tilt-rotor aircraft. First, the reference commands for airspeed and nacelle angles are calculated by analyzing the conversion corridor and the conversion path. Subsequently, based on the finite-time switching theorem, an average dwell time condition is designed to guarantee the stability in the switching process. Besides, considering the state vibrations and bumps may appear in switching points, the fuzzy weighted logic is employed to improve the system transient performance. For disturbance rejection, three extended state observers are designed separately to estimate the disturbances in the switched systems. Compared with the traditional auto disturbance rejection control and proportion integration differentiation control, this method overcomes the conservatism of wasting the whole model information. The control performances of robustness and smoothness are verified with simulation, which shows that the new smooth switching control scheme is more targeted and superior than the traditional design method.

基于TNESO的PMSLM分数阶自抗扰控制

线性自抗扰控制(LADRC)以结构简单、易于实现且抗干扰能力强的特点在永磁同步直线电机(PMSLM)中得到广泛应用,但电机启动和负载突变会导致LADRC系统中的线性扩张状态观测器(LESO)扰动估计精度下降。为此,提出一种基于时变增益非线性扩张状态观测器(TNESO)的PMSLM分数阶自抗扰控制策略。结合LESO和非线性扰动观测器(NDOB),并根据误差与增益的关系构建动态增益函数,设计新型状态观测器TNESO;在此基础上,以分数阶PDμ控制律代替线性状态误差反馈控制律(LSEF),建立改进型自抗扰速度控制系统,以进一步提高电机控制的实时性和鲁棒性。仿真与实验结果表明:所设计的速度控制系统可以有效减少直线电机启动、负载突变时的观测响应时间,抑制观测初始时刻扰动峰值,从而满足高性能的PMSLM速度控制要求。

Observer-Based Control for a Cable-Driven Aerial Manipulator under Lumped Disturbances

With the increasing demand for interactive aerial operations,the application of aerial manipulators is becoming more promising.However,there are a few critical problems on how to improve the energetic efficiency and pose control of the aerialmanipulator forpractical application.In this paper,a novel cable-drivenaerialmanipulatorused for remote water sampling is proposed and then its rigid-flexible coupling dynamics model is constructed which takes joint flexibility into account.To achieve high precision joint position tracking under lumped disturbances,a newly controller,which consists of three parts:linear extended state observer,adaptive super-twisting strategy,and fractional-order nonsingular terminal sliding mode control,is proposed.The linear extended state observer is adopted to approximate unmeasured states and unknown lumped disturbances and achieve model-free control structure.The adaptive super-twisting strategy and fractional-order nonsingular terminal sliding mode control are combined together to achieve good control performance and counteract chattering problem.The Lyapunovmethod is utilized to prove the overall stability and convergence of the system.Lastly,various visualization simulations and ground experiments are conducted,verifying the effectiveness of our strategy,and all outcomes demonstrate its superiorities over the existing control strategies.

基于ESO的仿蝙蝠扑翼飞行器姿态控制仿真

针对仿蝙蝠扑翼飞行器的纵向气动特性不稳定、易受扰动的问题,设计了一种基于扩张状态观测器(ESO)的姿态控制方法,实现了扑翼飞行器姿态的稳定与抗干扰控制。首先建立仿蝙蝠扑翼飞行器的动力学模型;进而在该模型基础上分析了扑翼飞行器的纵向稳定性;然后将系统的不确定部分与各种未知的外界扰动作为系统的总扰动,引入ESO模块对总扰动进行实时观测与跟踪;最后在原有的PID控制器中加入扰动补偿环节。数值仿真结果表明,基于ESO的控制算法对于仿蝙蝠扑翼飞行器的控制效果显著优于基于PID的控制方法,阶跃响应的调节时间加快41.27%,对系统输入的白噪声干扰波动峰值从6.02%降低到2.82%,正弦扰动的波动峰值从11.56%降低到3.22%。

基于LESO的PMSM转子位置估算误差补偿方法

高速永磁同步电机运行中,转子位置精确与否确定了系统运行性能优劣,对于只补偿一拍滞后和零阶保持器引起的角度误差,以及通过与前馈解耦做差获得误差角进行补偿的方法,在精度和动态性等方面性能欠佳。为此,通过分析转子位置估算误差产生原因,推导出误差角的通用型数学模型,提出一种基于线性扩张状态观测器(LESO)的转子位置估算误差补偿方法。基于推导模型设计出一种可提取转子位置误差角的LESO,并采用获得的转子位置误差角进行补偿。此转子位置误差角估算考虑了不同类型非理想因素的影响,以及动态过程中电感电压项对误差角的影响,精度高、动态性好。最后搭建系统实验平台,实验结果表明所提转子位置估算误差补偿方法在精度和动态性方面具有优势。

An Improved Deadbeat Predictive Current Control Method for SPMSM Drives with a Novel Adaptive Disturbance Observer

To improve the dynamic performance of conventional deadbeat predictive current control(DPCC)under parameter mismatch,especially eliminate the current overshoot and oscillation during torque mutation,it is necessary to enhance the robustness of DPCC against various working conditions.However,the disturbance from parameter mismatch can deteriorate the dynamic performance.To deal with the above problem,firstly,traditional DPCC and the parameter sensitivity of DPCC are introduced and analyzed.Secondly,an extended state observer(ESO)combined with DPCC method is proposed,which can observe and suppress the disturbance due to various parameter mismatch.Thirdly,to improve the accuracy and stability of ESO,an adaptive extended state observer(AESO)using fuzzy controller based on ESO,is presented,and combined with DPCC method.The improved DPCC-AESO can switch the value of gain coefficients with fuzzy control,accelerating the current response speed and avoid the overshoot and oscillation,which improves the robustness and stability performance of SPMSM.Finally,the three methods,as well as conventional DPCC method,DPCC-ESO method,DPCC-AESO method,are comparatively analyzed in this paper.The effectiveness of the proposed two methods are verified by simulation and experimental results.

基于FxTSMC-ESO的永磁同步电机调速系统滑模控制

针对永磁同步电机速度环中存在的外部负载扰动问题,为了提高速度环控制系统的动态性和鲁棒性,提出一种基于新型固定时间滑模控制器与扩张状态观测器的控制方法。所提出的滑模控制器简化了收敛时间公式,解决了快速响应与抑制抖振的矛盾。为了进一步提升调速系统的鲁棒性,采用固定时间收敛的扩张状态观测器对控制器的扰动进行前馈补偿,该观测器不仅可以减小趋近律的开关函数增益,还能实现扰动的精准观测。仿真验证了所提滑模控制方法的有效性。

基于双层CESO的电液伺服系统线性自抗扰控制

针对含高频噪声的阀控非对称缸不确定扰动抑制问题,采用扰动频率分层技术,利用线性扩张状态观测器低通滤波特性以及扰动估计速度和精度与带宽取值正相关性的特点,提出一种基于双层级联扩张状态观测器的阀控非对称缸电液伺服系统线性自抗扰方法。在分析双层级联线性扩张状态观测器稳定性基础上,与传统线性自抗扰控制方法进行了仿真对比研究。仿真结果表明:该控制方法继承了传统自抗扰控制优点,提高了不确定扰动估计速度和精度,有效抑制了含高频测量噪声不确定扰动带来的不利影响,可实现阀控非对称缸电液伺服系统的高性能控制。

基于ESO的分拣并联机器人无标定视觉伺服自适应滑模控制

针对无标定分拣并联机器人需获取精确图像雅可比矩阵的问题,同时为克服图像检测误差、建模误差及外部干扰对无标定视觉伺服系统的影响,提出一种基于扩张状态观测器(extended state observer,ESO)的分拣并联机器人无标定视觉伺服自适应滑模控制方法。通过将表征机器人图像空间与任务空间映射关系的图像雅可比矩阵与系统不确定项集总到同一通道的状态方程,引入ESO对分拣并联机器人视觉伺服系统的集总不确定性进行在线估计,设计一种基于扩张状态观测器的自适应积分滑模控制器,并通过设计自适应律动态调整滑模控制切换增益,以提高视觉伺服系统精度,同时达到抑制滑模控制抖振的效果。采用Lyapunov稳定性理论证明该控制方法的稳定性,最后通过仿真实验验证了所提出视觉伺服自适应滑模控制方法的可行性和有效性。

基于LESO的DFIG-GSC反馈线性化直接功率控制

为了提高双馈风力发电机网侧变换器(DFIG-GSC)这个强耦合非线性系统的性能,提出了一种反馈线性化直接功率控制策略。首先在αβ坐标系下建立以有功功率、无功功率为变量的DFIG-GSC的数学模型,针对模型中的强耦合项采用反馈线性化进行解耦,得到其线性模型,再结合滑模控制理论设计出功率内环的控制律。由于功率内环控制律中未建模部分和不确定因素会对控制效果产生影响,采用线性扩张状态观测器对其进行观测并对其控制量进行修正。同时电压外环采用滑模控制来提高直流侧电压的响应速度。最后搭建仿真模型与传统PI控制以及直接功率控制进行比较,验证了所提控制策略的合理性和有效性。

基于LESO的MMC-RPC反馈线性化直接功率控制

模块化多电平铁路功率调节器作为一个耦合的多变量非线性系统,传统PI控制的直接功率控制难以实现对系统的精确解耦.本文提出了一种基于线性扩张状态观测器的反馈线性化直接功率控制方法,根据Lie导数构建了模块化多电平铁路功率调节器(MMC-RPC)两输入/两输出功率仿射模型,设计了精确反馈线性化功率解耦控制器.针对不确定因素等扰动对精确反馈线性化控制效果的影响,设计了线性扩张状态观测器对扰动进行观测和补偿,实现了功率的精确跟踪控制.最后,通过MATLAB/Simulink平台搭建仿真模型对所提控制方法进行了验证.

基于改进LESO的四旋翼无人机模糊线性自抗扰控制方法

四旋翼无人机系统具有参数不确定性及强耦合性的特点,其飞行性能容易受到外部干扰而下降.为了保证四旋翼无人机飞行的稳定性,本文提出了一种基于改进线性扩张状态观测器(Linear Extended State Observer,LESO)的模糊线性自抗扰控制方法.通过模糊算法自适应调节线性自抗扰控制器的参数,基于Levant跟踪微分器跟踪四旋翼无人机位置及姿态角的二阶微分信号进而提取四旋翼无人机系统的总扰动,使用总扰动偏差及偏差的微分作为输入的模糊控制器来优化LESO对总扰动的估计精度.此外,分析了LESO的收敛性及闭环系统的稳定性.最后通过对比仿真验证了所提控制策略的有效性,并从系统的控制信号,动态响应能力和抗干扰能力等方面对控制方案的性能进行了定量分析.

基于连续可导ESO的虚拟同步机控制策略

在高比例新能源接入的电网中,虚拟同步机技术被广泛应用,但当面对系统扰动时其稳定性较差,可能会存在电压过限、频率波动等问题。因此,为了提高电能质量,将扩张状态观测器引入虚拟同步机控制技术中,对扰动进行观测、估计与补偿,提高系统稳定性,从而在新能源电源波动及大功率负荷投切时得到更稳定的母线电压及系统频率。此外,进一步对扩张状态观测器中的分段函数fal进行矫正,提出一种连续可导的扩张状态观测器控制算法,免去运算过程中的判断环节,突出了“小误差大增益”的特点,并对算法进行稳定性分析和确定参数选择范围。仿真与实验结果验证了所提策略的有效性与可行性。

基于LESO的轮式移动机器人滑模轨迹跟踪控制

针对轮式移动机器人在车轮打滑情况下的轨迹跟踪控制问题,提出了一种利用线性扩张状态观测器(Linear Extended State Observer,LESO)和积分滑模面的控制方案。首先,根据车轮打滑情况下的非完整约束条件建立轮式移动机器人的运动学模型。根据动能函数和拉格朗日方程建立其动力学模型。将这两种模型相结合得到力矩与速度相关的数学模型。其次,利用LESO对该数学模型进行扩张,并对总扰动进行估计。基于实际速度与虚拟速度之差设计带有积分项的滑模面,将扰动估计值前馈结合滑模面设计动力学控制器,并给出速度跟踪误差在有限时间内收敛的证明。最后,与基于超螺旋干扰观测器设计的控制方案仿真相比,所提出方案角速度跟踪误差在1 s左右时已趋于零,车轮力矩值稳定在3 N·m左右,且无锯齿抖动,扰动误差在1~5 s时波动更小,5~20 s时未出现明显锯齿抖动,仿真结果表明所提方案跟踪效果更好,抗干扰能力更强,观测精度更高。

Solid Rocket Booster Thrust Asynchrony Identification Method for Solid Rocket Bundled Rockets With ESO

The role of the rocket attitude control system is to execute the required maneuvers for guidance and ensure the stability of the rocket's flight attitude. Attitude control technology has always been one of the key technologies for ensuring the success of rocket flights and has been a core topic in carrier rocket technology research. The Gravity-1 solid carrier rocket is the first solid rocket bundled rocket developed by China, adopting a configuration with four boosters and a core stage bundled together. During the actual flight process, the four booster engines are ignited first, and then, in the event of insufficient control force from the boosters, the core stage engine is ignited to participate in control. To address thrust asynchrony during the descent of the four boosters, an Extended State Observer(ESO) is employed in the control scheme for this flight segment. This involves real-time estimation and compensation of attitude parameters during flight, identification of thrust asynchrony among the boosters, and simultaneous determination of whether the core stage engine is ignited to participate in control.Through six degrees of freedom simulation analysis and Y1 flight test validation, this method has been proven to be correct and feasible.

On geometric interpretation of extended state observer: a preliminary study

Borrowing the framework of the geometric approach, this paper tries to analyze and explain why it is possible for the extended state observer (ESO) to estimate the state vector and total disturbance accurately. The geometric approach has provided an elegant and rigorous framework to redefine some key concepts in modern control theory, such as controllability and observability. Moreover, those concepts can be extended to deal with systems in the presence of inaccessible disturbances, such as controlled invariants and conditioned invariants. It is shown in this paper that the augmented system of the ESO is unknown-state unknown-input completely reconstructable in finite time interval. A numerical simulation is given to verify the state vector and total disturbance can be estimated accurately by the ESO if the augmented system is unknown-state unknown-input completely reconstructable.

基于LESO的有源电力滤波器模型预测控制研究

针对在采用LCL滤波器作为输出滤波器的T型三电平有源电力滤波器拓扑中,在应用模型预测控制时存在的对电压、电流传感器需求量大、因系统建模不准确而产生的误差等问题,提出一种基于线性扩张状态观测器的改进有源电力滤波器系统模型。该模型对每一个开关周期内滤波器电容支路电压进行观测,将得到的结果应用于逆变器输出电流计算和有源电力滤波器预测控制模型的建立,能够减少1/3的对传感器的需求,并将因LCL滤波器而引入的误差考虑在控制策略之内,有效提高有源电力滤波器的控制精度和对谐波及无功的补偿效果。在此基础上提出了以逆变器输出电压为控制对象的模型预测电压控制策略。基于Matlab/Simulink的仿真验证了所提模型的有效性,并通过实验验证了其可行性。