基于ADRC的液压支护机器人自适应控制

为促进深层围岩液压支架自动化控制的研究,提出了一种基于ADRC的自适应控制系统。首先,通过液压支架支护系统的拉格朗日动力学分析,建立了液压支架动力学模型。针对该模型的动力耦合和时变特性设计了ADRC控制器,并对跟踪微分器、扩张观测器和非线性误差反馈3部分进行了离散化、分离式的参数整定。最终以MATLAB / Simulink为平台,对液压支架模型和控制系统进行了联合仿真实现,并设计了ADRC与PID控制的对比实验。仿真实验结果表明,该ADRC控制器与PID控制器相比具有更好的控制效果和运动品质。     

A robust decentralized load frequency controller for interconnected power systems

A novel design of a robust decentralized load frequency control (LFC) algorithm is proposed for an inter-connected three-area power system, for the purpose of regulating area control error (ACE) in the presence of system uncertainties and external disturbances. The design is based on the concept of active disturbance rejection control (ADRC). Estimating and mitigating the total effect of various uncertainties in real time, ADRC is particularly effective against a wide range of parameter variations, model uncertainties, and large disturbances. Furthermore, with only two tuning parameters, the controller provides a simple and easy-to-use solution to complex engineering problems in practice. Here, an ADRC-based LFC solution is developed for systems with turbines of various types, such as non-reheat, reheat, and hydraulic. The simulation results verified the effectiveness of the ADRC, in comparison with an existing PI-type controller tuned via genetic algorithm linear matrix inequalities (GALMIs). The comparison results show the superiority of the proposed solution. Moreover, the stability and robustness of the closed-loop system is studied using frequency-domain analysis.     

中储式磨煤机制粉系统的自抗扰控制

中储式磨煤机制粉系统是典型的三入三出系统。其具有强耦合。非线性。大惯性的特点。常规的PID很难满足其控制要求。自抗扰控制器是利用非线性控制理论而设计的新型控制器,能实现对被控对象的良好控制。本文利用了自抗扰控制器,设计了基于自抗扰技术的磨媒机制粉系统。仿真结果表明。自抗扰控制器有很强的抗干扰能力和鲁棒性,有很好的使用价值和应用前景。     

Robust tracking and distributed synchronization control of a multi-motor servomechanism with H-infinity performance

The multi-motor servomechanism (MMS) is a multi-variable, high coupling and nonlinear system, which makes the controller design challenging. In this paper, an adaptive robust H-infinity control scheme is proposed to achieve both the load tracking and multi-motor synchronization of MMS. This control scheme consists of two parts: a robust tracking controller and a distributed synchronization controller. The robust tracking controller is constructed by incorporating a neural network (NN) K-filter observer into the dynamic surface control, while the distributed synchronization controller is designed by combining the mean deviation coupling control strategy with the distributed technique. The proposed control scheme has several merits: 1) by using the mean deviation coupling synchronization control strategy, the tracking controller and the synchronization controller can be designed individually without any coupling problem; 2) the immeasurable states and unknown nonlinearities are handled by a NN K-filter observer, where the number of NN weights is largely reduced by using the minimal learning parameter technique; 3) the H-infinity performances of tracking error and synchronization error are guaranteed by introducing a robust term into the tracking controller and the synchronization controller, respectively. The stabilities of the tracking and synchronization control systems are analyzed by the Lyapunov theory. Simulation and experimental results based on a four-motor servomechanism are conducted to demonstrate the effectiveness of the proposed method.     

Predictive active disturbance rejection control for processes with time delay

Active disturbance rejection control (ADRC) has been shown to be an effective tool in dealing with real world problems of dynamic uncertainties, disturbances, nonlinearities, etc. This paper addresses its existing limitations with plants that have a large transport delay. In particular, to overcome the delay, the extended state observer (ESO) in ADRC is modified to form a predictive ADRC, leading to significant improvements in the transient response and stability characteristics, as shown in extensive simulation studies and hardware-in-the-loop tests, as well as in the frequency response analysis. In this research, it is assumed that the amount of delay is approximately known, as is the approximated model of the plant. Even with such uncharacteristic assumptions for ADRC, the proposed method still exhibits significant improvements in both performance and robustness over the existing methods such as the dead-time compensator based on disturbance observer and the Filtered Smith Predictor, in the context of some well-known problems of chemical reactor and boiler control problems.     

液压柔性机械臂奇异摄动法控制

将液压柔性机械臂系统分为相互耦合的两个部分，即柔性机械臂和液压伺服驱动系统，并通过一个驱动Jacobian矩阵构建其耦合关系。将作用于机械臂上的力视为一虚拟输入，运用奇异摄动法将柔性机械臂的模型分解为快慢两个子系统，其中慢变子系统控制器完成对期望轨迹的跟踪，而快变子系统控制器抑制柔性臂的振动。在此基础上，采用反演控制设计方法，得到液压伺服阀的位移控制律，使液压油缸的实际输出力完全满足柔性臂所需要的驱动力。数字仿真的结果验证了设计控制器的正确性和有效性。     

Nonlinear adaptive robust backstepping force control of hydraulic load simulator: Theory and experiments

High performance robust force control of hydraulic load simulator with constant but unknown hydraulic parameters is considered. In contrast to the linear control based on hydraulic linearization equations, hydraulic inherent nonlinear properties and uncertainties make the conventional feedback proportional-integral-derivative (PID) control not yield to high performance requirements. Furthermore, the hydraulic system may be subjected to non-smooth and discontinuous nonlinearities due to the directional change of valve opening. In this paper, based on a nonlinear system model of hydraulic load simulator, a discontinuous projection-based nonlinear adaptive robust back-stepping controller is developed with servo valve dynamics. The proposed controller constructs a novel stable adaptive controller and adaptation laws with additional pressure dynamic related unknown parameters, which can compensate for the system nonlinearities and uncertain parameters, meanwhile a well-designed robust controller is also synthesized to dominate the model uncertainties coming from both parametric uncertainties and uncertain nonlinearities including unmodeled and ignored system dynamics. The controller theoretically guarantee a prescribed transient performance and final tracking accuracy in presence of both parametric uncertainties and uncertain nonlinearities; while achieving asymptotic output tracking in the absence of unstructured uncertainties. The implementation issues are also discussed for controller simplification. Some comparative results are obtained to verify the high-performance nature of the proposed controller.     

A compound control strategy combining velocity compensation with ADRC of electro-hydraulic position servo control system

In order to enhance the anti-jamming ability of electro-hydraulic position servo control system at the same time improve the control precision of the system, a compound control strategy that combines velocity compensation with Active Disturbance Rejection Controller (ADRC) is proposed, and the working principle of the compound control strategy is given. ADRC controller is designed, and the extended state observer is used for observing internal parameters uncertainties and external disturbances, so that the disturbances of the system are suppressed effectively. Velocity compensation controller is designed and the compensation model is derived to further improve the positioning accuracy of the system and to achieve the velocity compensation without disturbance. The compound control strategy is verified by the simulation and experiment respectively, and the simulation and experimental results show that the electro-hydraulic position servo control system with ADRC controller can effectively inhibit the external disturbances, the precise positioning control is realized after introducing the velocity compensation controller, and verify that the compound control strategy is effective.     

基于自抗扰控制器的电液力伺服加载系统

在航空关节轴承疲劳寿命及性能评价试验中,采用电液力伺服加载控制系统来模拟关节轴承在工作中所承受的真实运动和载荷。传统PID控制技术在工程实际中大量应用,但其具有对于复杂系统控制精度减低及对环境变化的适应能力不足的缺点,因此无法满足试验机在复杂条件下受力载荷的高性能受力要求。引入自抗扰控制器(ADRC),评估系统的状态信息和扰动信息,解决在极端条件、无扰动数学模型下对动态载荷谱加载的精确控制问题。通过仿真与实验证明:在外部条件相同的情况下,自抗扰控制器在电液力伺服加载系统中的控制效果优于PID控制,系统的响应速度、抗干扰能力以及鲁棒性显著提高。     

A disturbance observer-based adaptive control approach for flexure beam nano manipulators

This paper presents a systematic modeling and control methodology for a two-dimensional flexure beam-based servo stage supporting micro/nano manipulations. Compared with conventional mechatronic systems, such systems have major control challenges including cross-axis coupling, dynamical uncertainties, as well as input saturations, which may have adverse effects on system performance unless effectively eliminated. A novel disturbance observer-based adaptive backstepping-like control approach is developed for high precision servo manipulation purposes, which effectively accommodates model uncertainties and coupling dynamics. An auxiliary system is also introduced, on top of the proposed control scheme, to compensate the input saturations. The proposed control architecture is deployed on a customized-designed nano manipulating system featured with a flexure beam structure and voice coil actuators (VCA). Real time experiments on various manipulating tasks, such as trajectory/contour tracking, demonstrate precision errors of less than 1%.     

基于死区补偿的电液位置伺服系统自抗扰控制

针对电液位置伺服控制系统的比例阀死区、参数不确定及外部未知扰动等问题,设计了由自抗扰控制器与死区逆补偿构成的串联控制器.首先基于实验辨识构造死区逆模型对死区进行预补偿,然后根据系统特性设计了一阶自抗扰控制器,构造改进的扩张状态观测器对"总扰动"进行实时估计,并通过非线性控制律给予主动补偿.联合仿真与试验结果表明,所提出...     

变转速泵控马达液压系统仿真分析

变转速液压驱动系统是一种新型的节能传动系统。本文对变转速泵控马达液压系统进行了仿真分析,建立了系统中变频器、异步电动机、定量泵、马达以及负载的数学模型。仿真中采用了PID控制、输入前馈及负载前馈相结合的复合闭环控制技术。仿真结果表明这种控制策略能有效地解决系统存在的速度刚性低,控制特性差等问题。     

A novel practical control approach for rate independent hysteretic systems

A disturbance rejection based control approach, active disturbance rejection control (ADRC), is proposed for hysteretic systems with unknown characteristics. It is an appealing alternative to hysteresis compensation because it does not require a detailed model of hysteresis, by treating the nonlinear hysteresis as a common disturbance and actively rejecting it. The stability characteristic of the ADRC is analyzed. It is shown that, in the face of the inherent dynamic uncertainties, the estimation and closed-loop tracking errors of ADRC are bounded, with their bounds monotonously decreasing with the observer and controller bandwidths, respectively. Simulation results on a typical hysteretic system further demonstrate the effectiveness of the proposed approach.     

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.     

含有测量时延摄动的冷轧机厚控系统控制器设计

针对冷带轧机液压厚控(Hydraulic automatic gauge control, HAGC)系统中带材厚度输出存在测量时延摄动以及系统存在不确定性的情况,提出一种新的控制器设计策略,以提高实际工作中冷带轧机板带材的板厚精度。基于轧机液压厚控系统各环节的方程式,给出具有测量时延摄动和不确定项的数学模型,并将该测量时延转化为时变输入时延考虑,建立最终的HAGC系统模型。针对该模型设计一种新的控制器,并利用Lyapunov稳定性理论对所设计的控制器进行严格的理论证明,得出系统的指数稳定性。针对1700单机架轧机进行Matlab仿真,将所提出的控制器与传统比例积分微分(Proportional integral derivative, PID)控制器的仿真结果进行对比,说明了该控制方法能够克服时延及不确定性的影响,比传统的PID控制器具有更加良好的效果,进一步验证了控制器的有效性和优越性。     

Robust absolute stability analysis for interval nonlinear active disturbance rejection based control system

Active disturbance rejection control (ADRC) is a relatively new, quite different but very practical control technology, which shows much promise in replacement of proportion-integration-differentiation (PID) with unmistakable advantage in performance and practicality. This paper mainly concerns with the robust absolute stability of the ADRC based control system with parameter perturbations of the plant, i.e., ADRC based interval control system. Firstly, the system is transformed into a perturbed indirect Lurie system. Then, the Popov criterion and its robust version are presented and some new methods are developed to analyze the (robust) absolute stability for the interval control system. Furthermore, an example is presented to illustrate (robust) absolute stability analysis via the above methods, which verifies the convenience and practicability of these methods and shows the strong stability robustness of ADRC in the presence of parametric uncertainties.     

集成式电静压伺服机构直流侧电压振荡抑制

电静压伺服机构属于泵控液压系统,驱动控制器将直流电转换为三相交流电以驱动伺服电泵旋转,进而使伺服机构产生往复运动。驱动控制器与伺服机构进行集成化设计可以有效降低强电电磁辐射,减小电缆长度,减少电接触点。但是在集成化设计中,需要降低直流侧支撑电容容量以减小驱动控制器体积。小容量支撑电容情况下,伺服机构作动时直流侧电压会出现不稳定振荡现象。通过主动缓冲的方法降低直流侧电压振荡幅度,满足集成化设计对直流侧电压稳定性和驱动控制器小体积的要求。     

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.     

A robust and adaptive force/position control for two cooperating robot arms under uncertainty

This paper presents a motion coordination of a two-cooperating robot arm when there are unknown system parameters and bounded input disturbances. The order of the model of the two-arm system is reduced. To control this, a force/position control scheme based on an inverse dynamics control scheme is devised. On the top of the control scheme, an adaptive control scheme to take care of parametric uncertainties, and a robust control scheme to compensate coupling forces between two arms and input disturbances are devised. The adaptive and the robust control scheme are derived based on a devised Lyapunov function. The adaptive control algorithm is practical since it does not require the feedback of the second derivative of joint angles and interacting forces. The robust control scheme guarantees that the tracking error of the leader arm and the interacting forces between two arms are confined in a certain region. Numerical examples using dual 3 degree of freedom robot arm are shown.     

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。