A GESO based MPC approach to contour error control of networked motion control system

This paper presents a generalised extended state observer (GESO) based model predictive control (MPC) approach to contour error control for networked multi-axis motion system (NMAMS) with network-induced delays. First, the uncertainties induced by the network-induced delays are modelled as an additive bounded disturbance, and a novel model predictive controller based on the GESO is designed for the uniaxial trajectory tracking control system. The GESO is used to estimate the system state and the disturbance simultaneously, and the effects of the uncertainties induced by the delays are eliminated by the proposed GESO based controller. Then the contour error estimation method is adopted, and a PID controller is designed to compensate the contour error. Finally, experiments are carried out to demonstrate the effectiveness of the proposed method.     

基于参考模型的扰动观测器控制系统

为了补偿控制系统的未知动态和外部扰动,论文提出一种基于参考模型的扰动观测器控制系统.首先,分析了二阶理想参考模型控制系统的设计,并通过闭环传递函数证明了参考模型控制系统的稳定性.然后,设计了二阶系统扰动观测器和基于参考模型的扰动观测器控制律,分析了二阶闭环控制误差系统收敛性.并推广到n阶控制系统,证明了n阶闭环控制误差系统稳定性.最后,仿真实验结果表明,与线性自抗扰控制(LADRC)系统相比,基于参考模型的扰动观测器控制系统阶跃响应的跟踪精度和抗扰性能明显优于LADRC系统,扰动的估计精度高,控制输入量小于LADRC系统;基于参考模型的扰动观测器控制系统正弦跟踪精度和扰动的估计精度也高于LADRC系统.该新型控制系统结构简单,抗扰性能好,控制效率高,具有重要的工程应用价值.     

Robust Repetitive Control and Disturbance Rejection Based on Two‐Dimensional Model and Equivalent‐Input‐Disturbance Approach

A new configuration of a modified repetitive‐control system has been devised for a class of strictly proper plants that suppresses exogenous disturbances and uncertainties in the dynamics of the plant. It extends the applicability of the control system. The system consists of four parts: a two‐dimensional augmented model of the plant, which takes into account the difference in characteristics between continuous control and discrete learning in repetitive control; an equivalent‐input‐disturbance estimator; a state observer; and a state‐feedback controller. A robust‐stability condition expressed in terms of a linear matrix equality is used to determine the gains of the observer and the controller. Finally, a comparison of our method with repetitive control based on linear active disturbance rejection control (LADRC) shows how effective our method is and that it is superior to LADRC‐based repetitive control.     

一类轻载电液位置伺服系统线性自抗扰控制

为解决一类轻载电液位置伺服系统线性自抗扰控制器设计过程中面临的阶次选择问题,本文从系统特性、频域等角度,分析自抗扰框架中“积分器串联结构”与轻载电液位置伺服系统之间的内在联系,得到轻载电液位置伺服系统在自抗扰控制框架下是本质“一阶”系统的结论,从而合理设计了1阶线性自抗扰控制器.在此基础上,提出了有效的控制器参数整定方法,并分析了闭环系统的稳定性.仿真和试验结果表明,与高阶相比1阶线性自抗扰控制器可以更好地控制动态过程较快、负载较轻的惯性负载电液位置伺服系统,为自抗扰控制在液压伺服领域的工程应用提供了参考.     

电液比例位置同步线性自抗扰控制

电液比例位置同步液压系统受到元件安装精度、死区非线性以及系统参数摄动等因素的影响,导致两侧子系统性能不一致进而引起位置不同步.针对这一问题,提出由位置控制器、死区补偿器、同步控制器组成的复合控制方案.首先,建立电液比例位置控制系统数学模型,并分析系统内部参数摄动及比例阀死区特性对同步控制精度造成的影响.在此基础上,设计线性自抗扰同步控制器,实现对系统内外扰动的实时估计与主动补偿,同时为提高液压缸动态性能,减小稳态误差,设计了比例阀死区补偿器.仿真和实验结果表明,自抗扰控制器有效地抑制了内外扰动,提高了位置同步控制精度,而死区补偿器的引入改善了系统动态响应性能,降低了稳态位置同步误差.     

线性自抗扰控制的抗饱和补偿措施

控制输入约束是实际工业过程中普遍存在的现象,然而控制器设计中通常都假设执行机构动态是线性的,因此当执行机构存在约束时,执行机构输出信号与控制器输出信号不一致,使系统的动态性能降低,甚至导致系统不稳定.本文针对线性自抗扰控制(linearactive disturbance rejection control,LADRC)执行机构的约束问题,提出两种抗饱和补偿方案,利用LADRC扩张状态观测器估计控制器状态或者控制器输出与执行器输出的误差,从而使LADRC能快速消除饱和.将这两种方法用到含执行机构饱和的一阶惯性加迟延被控对象进行仿真研究,结果表明两种补偿措施下线性自抗扰控制器能得到较好的控制性能.随后本文将LADRC抗饱和思想推广到负荷频率控制系统(load frequency control,LFC)中,仿真表明基于误差补偿的抗饱和方案对于LFC系统更为有效.     

线性自抗扰控制的适用性及整定

线性自抗扰控制将被控对象看成串级积分系统,把其他信息都当成不确定性.这种处理方法简单,但是对什么样的系统有效,目前还没有理论给出确定的答案.本文证明任何带有积分行为的严格正则传递函数都可以由线性自抗扰控制的反馈控制器等价实现,从而表明线性自抗扰控制具有广泛的适用性,即只要其他线性控制方法能够控制的系统,线性自抗扰控制同样可以适用.为简化线性自抗扰控制器参数整定,本文针对工业过程中广泛存在的PID控制器,提出将PID参数转化为二阶自抗扰控制参数的方法.该方法转化的线性自抗扰参数以带宽形式表示,从而保留了传统线性自抗扰简单易调的特性,为线性自抗扰控制在工业过程的应用准备了基础.     

基于VSG微网储能变流器无缝切换控制策略研究

针对微网储能变流器采用状态跟随控制器进行切换的过程中存在微小电压、电流扰动等问题,本文提出了一种基于线性自抗扰控制器(LADRC)的无缝切换控制策略。在采用P/Q控制和VSG控制相互切换方法的基础上,将电流内环控制器改成线性自抗扰控制器。通过设计一个状态观测器LESO实时在线观测估计输出变量直轴、交轴电流id、iq以及系统的各种扰动;将扰动估计值补偿给P/Q控制器和VSG控制器切换过程中的突变量,从而抑制切换过程中的电压、电流波动。最后,建立基于LADRC的储能变流器无缝切换仿真模型。仿真结果验证了该方法的可行性。     

线性自抗扰控制器的稳定性研究

研究了线性扩张状态观测器(Extended state observer, ESO)的估计能力,并且分析了在线性自抗扰控制(Linear active disturbance rejection control, LADRC)下闭环系统的稳定性. 对于系统模型未知的情形, 给出了线性扩张观测器估计误差有界的证明, 并通过分析得出了如下结论: 在扩张状态观测器跟踪误差趋于零的前提下, 在线性自抗扰控制下的闭环系统可以实现对设定信号的精确跟踪以及输入-输出有界(Bounded input and bounded output, BIBO)稳定.     

Anti‐windup design of active disturbance rejection control for sampled systems with input delay

A novel anti‐windup design of active disturbance rejection control (ADRC) is proposed for industrial sampled systems with input delay and saturation. By using a generalized predictor to estimate the delay‐free system output, a modified extended state observer is designed to simultaneously estimate the system state and disturbance, which could become an anti‐windup compensator when the input saturation occurs. Accordingly, a feedback controller is analytically designed for disturbance rejection. By proposing the desired closed‐loop transfer function for the set‐point tracking, a prefilter is designed to tune the tracking performance while guaranteeing no steady‐state output tracking error. A sufficient condition for the closed‐loop system stability is established with proof for practical application subject to the input delay variation. Illustrative examples from the literature are used to demonstrate the effectiveness and merit of the proposed control design.     

自抗扰实现飞翼布局无人机全包线飞行控制

本文以大展弦比飞翼布局无人机为研究对象,基于线性自抗扰控制(linear active disturbance rejection control,LADRC)理论设计了包含内环姿态控制和外环轨迹控制的全包线飞行控制器.在姿态控制中,提出一种抗时滞LADRC控制方法,可以有效解决控制延迟和执行机构动态特性引起的LADRC响应振荡;在轨迹控制中,考虑飞翼布局无人机的气动特性,分别设计了高度、航向、侧向偏离等常用飞行模态的跟踪控制器.仿真结果表明,在气动参数存在不确定性及强风干扰的全包线环境中连续飞行时,所设计的控制器具有较好的控制性能和较强的鲁棒特性.与常规全包线控制方案相比,本文设计的全包线飞行控制器待整定参数较少,参数整定过程相对简单,为进一步的工程应用提供了参考.     

负荷频率控制系统的线性自抗扰控制

本文研究负荷频率控制系统的线性自抗扰控制(linear active disturbance rejection, LADRC)方法. 考虑负荷频率控制系统的模型及结构, 本文首先通过一仿真例子分析了二阶和三阶LADRC在单区域电力系统的控制性能,指出二阶LADRC在负荷频率控制中的限制. 随后本文针对负荷频率控制中存在的发电速率约束(generation rate constraint, GRC)这一实际问题, 提出一种anti-GRC补偿方案. 该方案将汽轮机理论输出与实际输出误差作为扰动输入, 利用扩张状态观测器进行估计, 从而使LADRC能够快速补偿该误差, 达到抗积分饱和的作用. 最后, 本文将LADRC设计方法推广到具有再热汽轮机和水轮机系统以及多区域电力系统. 仿真表明LADRC是一种独立于模型的普适性控制结构, 所需整定参数少, 能够取得比PID控制更好的抗干扰性能, 可以应用到负荷频率控制系统中.     

Robust‐decentralized tracking control for a class of uncertain MIMO nonlinear systems with time‐varying delays

A new control design method based on signal compensation is proposed for a class of uncertain multi‐input multi‐output (MIMO) nonlinear systems in block‐triangular form with nonlinear uncertainties, unknown virtual control coefficients, strongly coupled interconnections, time‐varying delays, and external disturbances. By this method, the controller design is performed in a backstepping manner. At each step of backstepping procedure, a nominal virtual controller is first designed to get desired output tracking for the nominal disturbance‐free subsystem, and then a robust virtual compensator is designed to restrain the effect of the uncertainties, delays involved in the subsystem, and the couplings among the subsystems. The designed controller is linear and time‐invariant, so the explosion of complexity in the control law is avoid. It is proved that robust stability and robust practical tracking property of the closed‐loop system can be ensured, and the tracking errors can be made as small as desired. Copyright © 2013 John Wiley & Sons, Ltd.     

车辆线控转向路感模拟控制研究

针对车辆线控转向路感模拟控制受外界扰动大、建模困难等问题,基于线性自抗扰控制(LADRC)技术设计了一种车辆线控转向路感模拟控制算法.建立了线控转向路感控制仿真模型,包括驾驶员模型、线控转向系统模型、两自由度车辆模型、轮胎模型及控制器模型等,在给定道路函数条件下进行了系统仿真验证.结果表明,所设计的线性自抗扰控制器可以...     

基于自适应模糊控制器和非线性扰动观测器的永磁直线同步电机反馈线性化控制

由于永磁直线同步电机(PMLSM)伺服系统应用于一些高精密场合,因此克服系统存在的负载扰动、参数变化等不确定性影响是提高系统性能的关键.针对不确定性问题,采用一种基于自适应模糊控制器(AFC)和非线性扰动观测器(NDO)的反馈线性化控制方法.首先设计反馈线性化控制器(FLC)实现系统的线性化,便于位置跟踪;其次采用NDO估计并补偿系统的不确定性,提高跟踪精度.但在实际运行过程中观测器增益较难选取,极易产生较大的观测误差,为此,采用AFC方法逼近NDO的观测误差,通过自适应律动态调整模糊规则,改善模糊控制器的学习能力,增强系统的鲁棒性,并用李雅普诺夫定理保证系统闭环稳定性.实验结果表明,与基于DOB和NDO的反馈线性化位置控制相比,该方法能够明显提高系统的跟踪性和鲁棒性.     

基于高阶控制器设计的线性自抗扰控制参数调整

将反馈控制器/扩张状态观测器闭环极点配置在同一位置是线性自抗扰控制器(linear active disturbance rejection control,LADRC)最常用的整定方法.该方法只需调整两个参数,在工程应用上极为方便.但是,由于极点配置在同一位置的限制,整定的LADRC可能达不到期望的性能.本文提出以现有控制器参数为基础的LADRC调参方法.该方法以现有控制器参数为基础,通过降阶及逼近,保证LADRC控制能接近现有控制系统的性能.仿真设计表明采用高阶控制器设计的LADRC可以取得与原有控制系统相当的控制性能.该方法不受带宽法调参的需使反馈控制器及扩张观测器极点配置在同一位置的限制,因此可以期望获得比带宽法更好的性能.同时,该方法为已经熟悉掌握其他控制器设计方法的工程控制人员提供了一种便捷的调整线性自抗扰控制参数的方案,具有较好的应用价值.     

Stabilization and Tracking Control of X‐Z Inverted Pendulum Using Flatness Based Active Disturbance Rejection Control

A flatness based robust active disturbance rejection control technique scheme with tracking differentiator is proposed for the problem of stabilization and tracking control of the X‐Z inverted pendulum known as a special underactuated, non‐feedback linearizable mechanical system. The differential parameterization on the basis of linearizing the system around an arbitrary equilibrium decouples the underactuated system into two lower order systems, resulting in two lower‐order extended state observers. Using a tracking differentiator to arrange the transient process utilizes the problem of stabilization and tracking control and gives a relatively small initial estimation error, which enlarges the range of the controller parameters. The convincing analysis of the proposed modified linear extended state observer is presented to show its high effectiveness on estimating the states and the extended states known as the total disturbances consisting of the unknown external disturbances and the nonlinearities neglected by the linearization. Simulation results on the stabilization and tracking control of the X‐Z inverted pendulum, including a comparative simulation with an all‐state‐feedback sliding mode controller are presented to show the advantages of the combination of flatness and active disturbance rejection control techniques.     

悬挂伸缩刀具的树障清理空中机器人飞行控制方法

针对输电线路附近的树障进行清理问题,本文提出了一种新型的悬挂伸缩刀具的树障清理空中机器人并进行了仿真和实物验证.首先,对悬挂伸缩刀具的空中机器人进行了伸缩刀具重心变化下的动力学、运动学建模及接触建模.其次,为避免空中机器人接触作业时机器人倾翻的问题,设计了力估计器用于力感知和导纳控制器用于力控制.针对空中机器人非线性强耦合、伸缩刀具时参数摄动及作业时扰动的问题,设计了线性自抗扰控制(LADRC)的机器人位姿控制器.再次,数值仿真验证了导纳控制能有效避免空中机器人接触作业时产生倾翻的问题,以及基于LADRC控制器的位姿控制具有良好的稳定性和抗扰性.最后,通过实物飞行和接触作业测试,进一步验证了本文悬挂伸缩刀具的树障清理空中机器人及其控制方法的有效性.     

基于自适应线性自抗扰控制的飞机防滑刹车系统重构控制

飞机防滑刹车系统是确保飞机安全起飞、着陆和滑跑的重要航空机电系统. 除了其动力学中的强非线 性、强耦合以及参数时变外, 潜在的执行器等组件故障也会严重降低防滑刹车系统的安全性与可靠性. 为满足故障 及扰动状态下系统的性能需求, 本文提出了一种基于自适应线性自抗扰控制的飞机防滑刹车系统重构控制方法. 根据飞机防滑刹车系统的组成结构及工作原理对其进行数学建模, 并对执行器注入故障因子. 设计了自适应线性 自抗扰重构控制器, 同时分析了整个闭环系统的稳定性. 该控制器将组件故障、外部干扰以及测量噪声等视为总扰 动, 根据状态误差反馈和系统输出信息, 利用BP神经网络在线优化更新扩张状态观测器和状态误差反馈律参数, 从 而更精确地观测与补偿总扰动带来的不利影响. 最后, 在不同跑道环境下的仿真结果验证了所提出重构控制器的适 应性和鲁棒性.     

Performance analysis of 2‐DOF tracking control for a class of nonlinear uncertain systems with discontinuous disturbances

In this paper, the tracking control problem is considered for a class of uncertain nonlinear systems with infinite discontinuous points in the external disturbance. The extended state observer–based 2‐degree‐of‐freedom control is used with one degree to estimate and cancel the “total disturbance” and the other to force the closed‐loop system to have desired characteristics. The tracking error between the state vector and its ideal trajectory in the entire transient process is adequately discussed to illuminate the performance of resulting control systems. The quantitative analysis shows that the tracking error can be small enough by tuning the bandwidth of the extended state observer. Moreover, the necessary and sufficient condition for the tracking error and the estimation error of the “total disturbance” to converge to zero is presented. The simulation results of a motion test demonstrate that the desired performance of the control system can be achieved despite discontinuous disturbance and nonlinear uncertainties.