Observer-based State Feedback Control to Suppress Stick-slip Vibrations in Oil Well Drill-string

In drilling field, stick-slip vibrations of the drill-string are the main reason for the failure of the drilling system. To suppress the undesired stick-slip vibrations, an observer-based state feedback control method is proposed. The drilling system is described by a lumped parameter model including a Karnopp friction torque model. A state observer is designed to estimate the bit velocity in bottom hole and a state feedback controller is proposed to control the top drive velocity. By simulation, the performance of the control algorithm is demonstrated. Based on the control algorithm, a stick-slip vibration control system is developed. Test results show that the control system can effectively eliminate stick-slip vibrations of the drill-string and can be applied to the drilling field.

Nonlinear State Feedback Control of PEM Fuel Cell Systems

In this paper, the nonlinear state feedback controller has been developed to control the pressures of the oxygen and the hydrogen in the PEM（Proton Exchange Membrane） fuel cell system. Nonlinear model of the PEM fuel cell system was introduced to study the design problems of the state observer and model based controller. A cascade observer using the filtering technique was used to estimate the pressure derivatives of the cathode and the anode in the system. In order to estimate the pressures of the cathode and the anode, the sliding mode observer was designed by using these pressure derivatives. To estimate the oxygen pressure and the hydrogen pressure in the system, the nonlinear state observer was designed by using the cathode pressure estimates and the anode it. These results will be very useful to design the state feedback controller. The validity of the proposed observers and the controller has been investigated by using a Lyapunov＇s stability analysis strategy.

Adaptive Backstepping Output Feedback Control for SISO Nonlinear System Using Fuzzy Neural Networks

In this paper, a new fuzzy-neural adaptive control approach is developed for a class of single-input and single-output （SISO） nonlinear systems with unmeasured states. Using fuzzy neural networks to approximate the unknown nonlinear functions, a fuzzy- neural adaptive observer is introduced for state estimation as well as system identification. Under the framework of the backstepping design, fuzzy-neural adaptive output feedback control is constructed recursively. It is proven that the proposed fuzzy adaptive control approach guarantees the global boundedness property for all the signals, driving the tracking error to a small neighbordhood of the origin. Simulation example is included to illustrate the effectiveness of the proposed approach.

The Design of Output Feedback Distributed Model Predictive Controller for a Class of Nonlinear Systems

For a class of nonlinear systems whose states are immeasurable, when the outputs of the system are sampled asynchronously, by introducing a state observer, an output feedback distributed model predictive control algorithm is proposed. It is proved that the errors of estimated states and the actual system's states are bounded. And it is guaranteed that the estimated states of the closed-loop system are ultimately bounded in a region containing the origin. As a result, the states of the actual system are ultimately bounded. A simulation example verifies the effectiveness of the proposed distributed control method.

Output Feedback Nonlinear General Integral Control

This paper proposes an output feedback nonlinear general integral controller for a class of uncertain nonlinear system. By solving Lyapunov equation, we demonstrate a new proposition on Equal ratio gain technique. By using Equal ratio gain technique, Singular perturbation technique and Lyapunov method, theorem to ensure regionally as well as semi-globally exponential stability is established in terms of some bounded information. Moreover, a real time method to evaluate the ratio coefficients of controller and observer are proposed such that their values can be chosen moderately. Theoretical analysis and simulation results show that not only output feedback nonlinear general integral control has the striking robustness but also the organic combination of Equal ratio gain technique and Singular perturbation technique constitutes a powerful tool to solve the output feedback control design problem of dynamics with the nonlinear and uncertain actions.

带有状态/输入量化的无人艇航向跟踪控制

[目的]针对水面无人艇(USV)的海上通信受限的问题,提出一种带有状态/输入量化的USV航向跟踪控制方法。[方法]基于反步法设计系统控制律,结合动态面技术降低虚拟控制律的计算量膨胀问题。对于控制系统中存在的不确定项及外界干扰,利用扩张状态观测器(ESO)进行估计。采用均匀量化器分别对控制系统中的状态变量和控制输入进行量化,且量化后的状态反馈信息仅用于跟踪控制。利用量化状态递归设计基于ESO的USV航向控制器,证明闭环控制系统中量化变量和非量化变量间误差的有界性。[结果]基于李雅普诺夫稳定性理论,提出了量化误差考量及闭环系统稳定性判定方法,严格证明了所设计的带有状态量化和输入量化的USV航向跟踪控制系统的稳定性,仿真实验验证了该控制策略的有效性。[结论]结果表明,所提方法可为USV航向跟踪控制提供借鉴。

基于自抗扰方法的无人机控制律设计

针对多平台、多任务的无人机飞行控制律的快速开发问题,提出一种基于自抗扰方法的无人机控制律架构,设计了可复用的扩展状态观测器及微分跟踪器,研究对比了其在3种具有较大差异的无人机平台中的应用,使7 000 kg的超音速UAV_A获得了更优的敏捷性结果,在60 kg的缩比UAV_B完成了5.8g的半滚倒转大过载机动飞行试验,基于10 kg的平直翼UAV_C实现了12架机紧编队的精确轨迹控制飞行试验。仿真及试飞结果表明:所提自抗扰控制结构响应快速、控制精度高、鲁棒性强,能够较好地适应多类无人机、面向多种任务场景的控制需求,且不需调参就能够获得较好的控制效果,为飞行控制算法设计提供了新的技术途径。

Adaptive RISE Control of Winding Tension with Active Disturbance Rejection

A winding system is a time-varying system that considers complex nonlinear characteristics,and how to control the stability of the winding tension during the winding process is the primary problem that has hindered development in this field in recent years.Many nonlinear factors affect the tension in the winding process,such as friction,structured uncertainties,unstructured uncertainties,and external interference.These terms severely restrict the tension tracking performance.Existing tension control strategies are mainly based on the composite control of the tension and speed loops,and previous studies involve complex decoupling operations.Owing to the large number of calculations required for this method,it is inconvenient for practical engineering applications.To simplify the tension generation mechanism and the influence of the nonlinear characteristics of the winding system,a simpler nonlinear dynamic model of the winding tension was established.An adaptive method was applied to update the feedback gain of the continuous robust integral of the sign of the error(RISE).Furthermore,an extended state observer was used to estimate modeling errors and external disturbances.The model disturbance term can be compensated for in the designed RISE controller.The asymptotic stability of the system was proven according to the Lyapunov stability theory.Finally,a comparative analysis of the proposed nonlinear controller and several other controllers was performed.The results indicated that the control of the winding tension was significantly enhanced.

一类严格反馈非线性系统的快速鲁棒控制

针对一类具有外部扰动的高阶严格反馈非线性系统,提出一种新型反正切扩张状态观测器并证明其观测误差有界。结合Lyapunov稳定性理论,设计一种鲁棒控制器,并证明了系统跟踪误差有界。文章给出一个仿真例子检验了所提方法的有效性。

基于自抗扰的反应器温度控制设计及仿真

连续搅拌釜式反应器在化工行业应用广泛,该反应器内的温度控制直接影响产品质量,故研究其温度控制意义重大。根据反应器的工作机理及系统辨识方法得到含有延迟环节的过程模型。在此基础上,应用自抗扰控制原理,引入系统扩张状态观测器并形成反馈控制率,从而完成自抗扰温度控制器的设计,最后对整个系统进行了模拟仿真。实验表明,该控制器的状态观测器可以有效跟踪输入信号和扰动信号。通过与传统的反馈控制器相比较,自抗扰系统具有更快的调节时间,较低的超调量以及鲁棒性强的特点。因此,基于自抗扰技术设计的温度控制器具备更强的环境适应能力。

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。

高空舱进气环境压力模拟新型自抗扰控制

高空舱进气环境压力模拟控制系统在发动机开展过渡态试验中存在强气流扰动及大量随机噪声干扰,为此,提出新型非线性状态误差反馈函数xal及在结构上引入总扰动状态变量反馈环节来设计扩张状态观测器算法(记作xal-ESO),并以此提出基于xal-ESO的高空舱进气环境压力模拟新型自抗扰控制方法。借助数值仿真对比所提出的xal-ESO与常见ESO在状态与总扰动方面的估计能力,结果表明xal-ESO能有效抑制系统输出噪声并取得较好的估计品质。基于系统核心设备模型搭建高空舱进气环境压力模拟仿真平台并进行工程试验,对比了基于xal-ESO的自抗扰控制与当前工程中使用的线性自抗扰控制的进气环境压力控制效果,试验结果显示线性自抗扰控制方法受噪声影响明显,而所提出的新型自抗扰控制方法在发动机过渡态试验中跟踪进气压力时超调量降低了58.70%,稳态误差降低了95.71%,表明该方法能够有效提升高空舱进气环境压力模拟效果,提升发动机过渡态性能评价的准确性。

基于LMI的水轮机调节系统扰动观测状态反馈控制策略研究

为进一步提高水轮机的调节性能和控制精度,针对水轮机调节系统提出了一种基于线性矩阵不等式(LMI)的扰动观测状态反馈控制策略。首先,对水轮机调节系统进行了建模,并设计了一种基于LMI的扰动观测状态反馈控制策略,该策略综合考虑了水轮机的运行状态及扰动观测值;然后通过LMI完成了该控制器的设计与分析;最后,为了验证所提控制策略的有效性和鲁棒性,通过仿真试验进行了测试。结果表明,与传统的控制方法相比,该扰动观测状态反馈控制策略可有效提高水轮机调节系统的响应速度、准确性和稳定性,且降低了系统对扰动的敏感性。

轮式移动工业机器人非奇异终端滑模轨迹跟踪控制

针对轮式移动工业机器人内、外扰动带来的不确定性对轨迹跟踪精度的影响,提出了一种非奇异终端滑模轨迹跟踪控制方法。首先建立了轮式移动工业机器人的动力学模型和轨迹跟踪误差模型;然后设计了扩张状态观测器来估计系统中的不确定性,并设计了非奇异终端滑模控制律,通过对不确定性实时补偿,来抑制内、外扰动对控制系统的影响,实现了轮式移动工业机器人运动轨迹的高精度控制;最后利用Lyapunov理论进行了稳定性分析。仿真结果表明,设计扩张状态观测器能够准确估计出系统中的不确定性,估计的速度和角速度最大误差分别仅为0.02 m/s和0.03 rad/s,设计的非奇异终端滑模控制律与扩展卡尔曼控制方法和积分滑模面控制方法相比,具有更高的跟踪精度和更强的鲁棒性,轨迹跟踪的最大误差仅为0.04 m。测试结果验证了提出的控制方法符合设计预期,轨迹跟踪的最大误差仅为0.07 m,能够确保轮式移动工业机器人更加准确地跟踪期望轨迹。

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MIMO-ESO的高速飞行器自抗扰控制

针对高速飞行器无动力再入过程中具有强耦合、气动参数摄动及不确定性的非线性姿态模型,设计了高速飞行器MIMO-ESO自抗扰姿态控制器。考虑各通道间的耦合影响,结合自抗扰控制中的扩张状态观测器及非线性状态误差反馈律,将不确定性、耦合及参数摄动等干扰作为“总和干扰”,利用扩张状态观测器进行估计并动态反馈补偿,再利用非线性状态误差反馈律抑制补偿残差。仿真结果表明,MIMO-ESO自抗扰控制器能够克服干扰及气动参数大范围摄动的影响,在获取良好的动态品质和跟踪性能的同时,具有较强的鲁棒性,克服了实际工程中难以建立精确被控模型并获取参数摄动范围的困难,具有工程应用价值。

卷到卷制程中基于降维观测器的优化状态反馈控制方法

卷到卷(roll-to-roll,R2R)制程普遍应用于柔性材料的量化生产中,其套色精度是产品质量的关键因素。R2R制程是一个多输入多输出、强耦合的复杂生产过程,实现高速高精度套色控制是其基本要求。首先,根据R2R印刷系统的状态空间模型,设计了基于降维观测器的状态反馈控制方法,同时通过粒子群优化算法对状态反馈的极点进行优化,实现了套色误差的高精度控制。将提出的套色控制方法与最新发表的全解耦比例微分(fully decoupled proportional-derivative,FDPD)套色控制方法进行对比,所提方法在套色精度上获得了50%~80%的提升,调节时间缩短了50%~65%,控制量绝对值之和仅为FDPD控制方法的46%~57%,这不仅减少了对执行机构的冲击,也节约了能量。对比结果证实了降维观测器的估值准确性,也表明所提方法能够明显提高控制性能。

基于ESO与线性化反馈的磁悬浮球系统自适应全局积分滑模控制

【目的】本文针对磁悬浮球系统的非线性特性、不确定性以及其易受外部扰动影响的特性,将线性化反馈控制与自适应全局积分滑模控制(AGISMC)相结合,优化系统控制效果、提高控制精度。【方法】首先,通过线性化反馈建立数学模型,使用自适应控制实现对系统参数的实时估计,降低系统的不确定性;其次,引入全局函数以改善系统的瞬态响应,将滑模函数中的符号函数替换为饱和函数以减小系统抖振;再次,在不确定干扰方面,利用扩张状态观测器(ESO)对系统未知干扰信号做出实时估计;最后,基于Matlab/Simulink进行仿真分析,并搭建试验平台进行试验验证。【结果】仿真和试验结果表明:AGISMC-ESO控制器与比例积分微分(PID)控制器在阶梯响应时均没有超调,且本文设计的AGISMC-ESO控制器到达稳态的时间更短;AGISMC-ESO控制器能在扰动出现后更快进行补偿,使系统快速到达稳态;施加正弦信号下,磁悬浮系统的实际运动轨迹与ESO所观测的位移曲线基本吻合。【结论】与PID控制器相比,本文设计的AGISMC-ESO控制器具有更快的响应速度、更高的控制精度、更好的动态跟踪性能和更优的抗干扰性能。

Research on improved active disturbance rejection control of continuous rotary motor electro-hydraulic servo system

In order to meet the precision requirements and tracking performance of the continuous rotary motor electro-hydraulic servo system under unknown strong non-linear and uncertain strong disturbance factors,such as dynamic uncertainty and parameter perturbation,an improved active disturbance rejection control(ADRC)strategy was proposed.The state space model of the fifth order closed-loop system was established based on the principle of valve-controlled hydraulic motor.Then the three parts of ADRC were improved by parameter perturbation and external disturbance;the fast tracking differentiator was introduced into linear and non-linear combinations;the nonlinear state error feedback was proposed using synovial control;the extended state observer was determined by nonlinear compensation.In addition,the grey wolf algorithm was used to set the parameters of the three parts.The simulation and experimental results show that the improved ADRC can realize the system frequency 12 Hz when the tracking accuracy and response speed meet the requirements of double ten indexes,which lay foundation for the motor application.