H型精密运动平台交叉耦合模糊PID同步控制

针对双直线电机驱动的H型精密运动平台由于永磁直线同步电机参数变化和扰动等不确定因素致使两边的运动不同步问题,提出一种交叉耦合模糊PID控制方法.在单轴中采用模糊PID控制作为位置控制器,速度控制器用普通的PI控制,以保证单轴跟踪精度;双轴间引入交叉耦合控制方法,消除双电机之间存在的机械耦合,进而减小了双轴间的位置同步误差.结果表明,将交叉耦合与模糊PID相结合的控制方法能够使H型精密运动平台的同步误差收敛于零,并且使系统具有较好的跟踪性能与鲁棒性.     

两自由度机械手臂的交叉耦合模糊逻辑控制

针对两自由度机械手臂难以建立数学模型的问题,提出了一种交叉耦合的两级控制系统.利用MATLAB Simulink对建立的交叉耦合模糊逻辑控制器的性能进行了模拟仿真,并与传统的PID控制器、基于遗传算法优化的PID控制器进行对比分析.结果表明:搭建的交叉耦合模糊逻辑控制器对立臂转角和悬臂转角阶跃响应的稳定时间分别为0. 05和0. 12 s,该控制器具有较高的控制精度和收敛速度,在控制稳定性、响应速度和超调量等方面的性能均明显优于其他算法,对两自由度机械手系统具有优异的控制性能.     

基于Fuzzy-PID智能车舵机控制系统

为提高智能车舵机的响应速度,分析了智能车控制系统的特点以及应用常规模糊控制器进行控制的局限性,提出了模糊PID控制算法.推导出模糊PID控制器消除稳态误差的原理,并介绍了模糊PID控制器的设计方法.实验结果表明,模糊PID控制器既能消除稳态误差,又有很强的鲁棒性,对于具有非线性和迟滞性特点的智能车舵机控制系统具有良好的控制性能.     

一种基于模糊滑模监督控制的速度控制器

提出了一种带监督控制器的模糊滑模控制方法,利用监督控制器来保证当系统状态误差远离滑模面时,能迫使系统加速向滑模面运动．先用试错法和直接自适应模糊控制方法设计模糊控制器,然后用改进的滑模函数调整模糊控制器参数以减小系统的抖振,用监督控制器来增强系统的鲁棒性．仿真结果表明,该控制方法是可行的．     

Cross-coupled controller design for triaxial motion systems based on second-order contour error estimation

The cross-coupled control(CCC)is widely applied to reduce contour errors in contour-following applications.In such situation,the contour error estimation plays an important role.Traditionally,the linear or second-order estimation approach is adopted for biaxial motion systems,whereas only linear approach is available for triaxial systems.In this paper,the second-order contour error estimation,which was presented in our previous work,is utilized to determine the variable CCC gains for motion control systems with three axes.An integrated stable motion control strategy,which combines the feedforward,feedback and CCC controllers,is developed for multiaxis CNC systems.Experimental results on a triaxial platform indicate that the CCC scheme based on the second-order estimation,compared with that based on the linear one,significantly reduces the contour error even in the conditions of high tracking feedrate and small radius of curvature.     

Interpolation-based contour error estimation and component-based contouring control for five-axis CNC machine tools

High accuracy contour error estimation and direct contour error control are two major approaches to reduce the contour error. However, two key factors make them complex for five-axis machine tools: the nonlinear kinematics and the coupling between the tool position and orientation. In this study, by finding the reference point nearest to the current actual position, and interpolating the point with two neighboring reference points and using the distance ratio, a new contour error estimation method for five-axis machine tools is proposed, which guarantees high accuracy while depending on only the reference points. By adding a weighted contour error on the tracking error in the workpiece coordinate system, and specifying a desired second-order error dynamics based on the error variable, an effective contouring control method is proposed, which can alleviate the problem: when the contour error components are introduced into the controller, the contour errors increase instead in some regions of the tracking trajectory. A series of experiments are performed on a tilting-rotary-table (TRT) type five-axis machine tool. The results reveal that the proposed estimation method has high accuracy, and compared with the case without contour error control, the proposed control approach can reduce the contour error along the whole trajectory.     

三轴运动平台改进型交叉耦合轮廓控制

为了削弱负载扰动及复杂轮廓误差模型对轮廓精度的影响,在单轴中采用比例控制作为位置环控制器,采用PDFF控制作为速度环控制器,以保证单轴跟踪精度.三轴间采用一种轮廓误差估算法来建立轮廓误差模型,运算更为简单.通过改进的交叉耦合控制结构进行轮廓控制器的设计,将轮廓误差的补偿量置于位置控制器前,能够实现跟踪误差与轮廓误差同时减小,以满足三轴运动平台的高精度加工要求.结果表明,改进后的三轴运动平台控制系统具有较高的轮廓精度和较强的抗扰性.     

A Proposal of Adaptive PID Controller Based on Reinforcement Learning

Aimed at the lack of self-tuning PID parameters in conventional PID controllers, the structure and learning algorithm of an adaptive PID controller based on reinforcement learning were proposed. Actor-Critic learning was used to tune PID parameters in an adaptive way by taking advantage of the model-free and on-line learning properties of reinforcement learning effectively. In order to reduce the demand of storage space and to improve the learning efficiency, a single RBF neural network was used to approximate the policy function of Actor and the value function of Critic simultaneously. The inputs of RBF network are the system error, as well as the first and the second-order differences of error. The Actor can realize the mapping from the system state to PID parameters, while the Critic evaluates the outputs of the Actor and produces TD error. Based on TD error performance index and gradient descent method, the updating rules of RBF kernel function and network weights were given. Simulation results show that the proposed controller is efficient for complex nonlinear systems and it is perfectly adaptable and strongly robust, which is better than that of a conventional PID controller.     

基于ADRC的直接转矩控制系统及其性能

在传统的直接转矩控制(DTC)系统中,速度控制通常采用PI控制器,而PI控制器必须依赖被控对象的数学模型,特别是在低速范围内不能达到令人满意的控制效果.将一种非线性控制器——自抗扰控制器(ADRC)引入直接转矩控制系统,以改善动态性能,并结合转矩控制系统提出了自抗扰控制器的参数整定方法,同时针对系统的抗扰性能进行了仿真分析.仿真结果表明,采用ADRC的转矩控制系统抗扰性能有显著提高.     

基于事件触发的大规模互联非线性系统的自适应分散漏斗控制

研究了一类不确定大规模非线性系统的分散自适应事件触发漏斗控制问题。首先,利用一个新的带有障碍李雅普诺夫函数的漏斗控制方法,构造了一种自适应分散漏斗控制器,以实现给定瞬态行为的输出跟踪。其次,为了解决控制器设计中的互联项问题,引入了一个辅助非线性函数。同时,将命令滤波技术应用到反步设计中,避免了反步过程中的“复杂性爆炸”问题。此外,还设计了一种事件触发机制,以减少控制器和执行器之间不必要的传输,从而提高资源效率。结果表明,所提出的控制方案能保证闭环系统的所有信号都是有界的,并且跟踪误差总是在漏斗中演化。最后,通过一个数值系统验证了该控制方法的有效性。     

变结构自适应控制系统研究

为了改善控制系统瞬态性能,本文从系统稳定性原则出发,提出了多模系统的变结构自适应控制策略,这种控制方法比变结构控制或自适应控制都优越,具有两者的优点.一方面可以适应参数变化,另一方面又可以调节系统的瞬态性能,使系统具有强鲁棒性.     

一种高阶系统的分数阶IMC-ID~μ控制器设计

针对高阶系统提出了一种模型降阶以及分数阶内模IDμ控制器设计方法。首先基于积分平方误差(ISE)性能指标,利用微粒群优化(Particle Swarm Optimization,PSO)算法将高阶系统模型降阶为含有时滞环节的分数阶模型;然后根据内模控制(Internal Model Control,IMC)原理,并用一阶泰勒表达式逼近模型中的时滞环节,推导出了分数阶IMC-IDμ控制器,该控制器仅包含一个可调参数;最后根据系统的最大灵敏度指标,实现了控制器参数的鲁棒整定。仿真结果表明,本文方法可使系统同时具有较好的动态响应、干扰抑制性能以及克服参数摄动的鲁棒性。     

静止无功补偿器的神经元生物智能电压控制仿真

为改善静止无功补偿器传统PID电压调节器的动态调节效果．增强其自适应能力,提出了一种基于神经元控制双层结构生物智能控制器的设计方法,其一级控制单元采用神经元控制,二级控制单元采用传统PID控制,神经元控制器根据实时误差动态调节PID控制器输人的给定值以提高控制效果．采用MATIAB中S—function模块并结合S一函数编程方法建立了控制器的仿真模型。然后用其替代静止无功补偿器控制系统中的P1D电压调节器．仿真结果表明：基于神经元的生物智能控制电压调节器能快速、灵活地调节电压,维持系统电压稳定．     

双永磁同步电动机的交叉耦合同步协调控制

该文分析了永磁同步电动机的数学模型,并在给出交叉耦合控制算法的基础上,设计了一个基于交叉耦合的双永磁同步电动机控制系统,将交叉耦合算法引入双电机同步控制,最后对系统进行了仿真。仿真结果表明,交叉耦合控制能有效地减小双永磁同步电动机同步协调控制的系统误差,验证了控制方案的正确性和可行性。     

建筑结构基于有限状态输出反馈的准滑模控制

为了较好地解决有限状态输出反馈条件下建筑结构滑模控制系统过大的抖振,提出了含饱和函数的指数趋近律形成的控制律和含继电特性连续函数的指数趋近律形成的控制律,基于这两种控制律,采用有限状态输出反馈的准滑模控制方法对地震作用下建筑结构的振动控制问题进行了研究.算例数值分析结果表明,所提出的准滑模控制方法,控制效果明显,能有效地减小结构的地震峰值响应,且控制系统的抖振很小.     

H_∞PSS设计中加权函数的选择及模型降阶

基于H∞鲁棒控制理论的基本原理,设计了电力系统稳定器,克服了传统电力系统稳定器(PSS)鲁棒性差的缺点。针对H∞PSS设计中,权函数的选择较困难,以及H∞PSS阶数往往很高的缺陷,提出了选择权函数时较为通用的方法,以及基于Gram矩阵的均衡降阶方法,并说明了当直接从MATLAB工具箱得到的H∞PSS不是最小实现模型时,如何降阶。为了与传统PSS进行比较,针对单机无穷大系统受到扰动后发生低频振荡的例子,给出了几组仿真试验结果。结果表明H∞PSS能够在较大的运行范围内抑制振荡,显示了良好的鲁棒性。     

Trajectory synchronization of multi-cylinder electrohydraulic lift system with huge load

A kind of four degree-of-freedom (DOF) electrohydraulic lift system is studied in this paper, after analyzing the motion characteristics and the mathematic model of the hydraulic cylinders, a cross-coupled synchronization method with load force and synchronization error feedback had been proposed to solve the synchronization problem encountered when realizing the needed roll and pitch attitude of the lift system. In this paper, mathematic model of asymmetric hydraulic cylinder was established and the lift system had been simplified to a dual-cylinder system. By incorporating the load force and the displacement of each cylinder, a cross-coupled synchronized control method was proposed to fit each cylinder’s tracking performance and multi-cylinder’s trajectory synchronization property. The proposed method not only solved the synchronization problem when multi-cylinder had a same trajectory, but also could fit the coordinated synchronization need when different trajectories of multi-cylinder were desired. Simulations and experiments on a four DOF electrohydraulic lift system with load of 100 tons verified the effectiveness of the proposed method.     

具有未知死区的SISO非仿射非线性系统间接自适应模糊控制

为了解决含有未知死区输入特性的SISO非仿射非线性系统的跟踪控制问题,提出了基于模糊自适应方法的控制器设计方案,把未知死区分解为一个线性项和一个扰动类似项,当系统状态可测时,利用模糊逻辑系统设计间接自适应模糊控制器,并结合跟踪误差信息设计自适应律;系统状态不可测时,通过引入误差观测器估计的状态变量,设计了间接自适应模糊输出反馈控制器．理论论证过程说明两种控制器能使系统的跟踪误差最终收敛到零的某一邻域,且闭环系统所有信号均有界. 仿真实验结果表明利用所设计控制方案可以使系统完成跟踪控制任务．     

基于免疫反馈机理的温度自动控制研究

基于生物免疫系统的反馈机理，提出了一种用免疫控制器与传统PI控制器相结合的复合控制方法，印将传统PJ控制器与免疫控制器相“串联”，在传统PI控制器参数已经优化的情况下，用免疫控制器对其输出进行“再处理”．并针对实际系统提出了一种限制超调量的误差参数函数，介绍了控制系统参数整定的方法．仿真和实验表明，这种复合控制的方法能有效地改善金属有机化合物化学气相淀积系统温度的控制性能．     

Contouring error modeling and simulation of a four-axis motion control system

A layered modeling method is proposed to resolve the problems resulting from the complexity of the error model of a multi-axis motion control system. In this model, a low level layer can be used as a virtual axis by the high level layer. The first advantage of this model is that the complex error model of a four-axis motion control system can be divided into several simple layers and each layer has different coupling strength to match the real control system. The second advantage lies in the fact that the controller in each layer can be designed specifically for a certain purpose. In this research, a three-layered cross coupling scheme in a four-axis motion control system is proposed to compensate the contouring error of the motion control system. Simulation results show that the maximum contouring error is reduced from 0.208 mm to 0.022 mm and the integration of absolute error is reduced from 0.108 mm to 0.015 mm, which are respectively better than 0.027 mm and 0.037 mm by the traditional method. And in the bottom layer the proposed method also has remarkable ability to achieve high contouring accuracy.