非线性离散系统的自适应PID控制器

针对非线性离散系统设计了利用TSK(Takagi Sugeno Kang)模糊模型的自适应PID控制器。利用模糊模型预测控制信号误差,通过控制信号误差自适应PID控制器参数。比较系统输出和模糊模型输出自适应模糊模型的参数。该方法可以弥补系统参数的模糊性、数学模型的模型误差和系统参数的变化。非线性离散系统的仿真实验验证了所设计的自适应PID控制器对非线性离散系统控制的有效性。     

一种新型模糊非线性PID控制器

采用一维输入一维输出的模糊映射关系与传统PID控制器相级联的方式，构成一个模糊非线性PID控制器以提高现有PID控制器的性能．一维模糊控制器无需选择与调整量化因子和比例因子，采用五条规则，易于实现．数值仿真和误差泛函积分评价指标表明，所提出的模糊非线性PID控制器比现有控制器具有更好的动静态性能．     

适用于非线性对象的模糊-神经元控制方法

针对具有严重非线性的受控对象，提出了一种模糊-神经元控制方法。该方法将模糊PID控制器与神经元控制器相结合，用于改善控制器控制非线性对象的性能，以误差、误差变化率及设定值的变化来自调整神经元控制器增益，提高了控制系统的响应速度和鲁棒性。将所提出控制方法用于pH中和过程控制，仿真实验结果表明，该方法具有满意的控制品质及很强的适应性。     

一类非线性系统的积分变结构模糊自适应跟踪控制

针对一类具有未知常数控制增益的不确定非线性系统,基于变结构控制原理,并利用具有非线性可调参数的模糊系统逼近等价控制,提出一种具有监督控制器的积分变结构模糊自适应跟踪控制策略.该策略通过监督控制器保证闭环系统所有信号有界.进一步,通过引入最优逼近误差的自适应补偿项来消除建模误差的影响.理论分析证明了跟踪误差能够收敛到零.仿真结果表明了该方法的有效性.     

基于自适应模糊PID控制器的非线性系统仿真

对于缺乏精确模型的过程或参数时变的滞后过程,传统PID控制难以达到良好的控制效果.普通模糊控制能够对一些非线性系统进行控制,并不需被控对象精确的数学模型,但是模糊控制难以消除系统的静态误差.针对复杂的非线性系统,设计了自适应模糊PID控制器.该控制器将模糊控制的动态性能好的优点和PID控制的稳态精度高的优点结合起来,采用模糊控制与PID控制分段控制策略,当偏差大于某一阈值时,采用模糊推理的方法调整系统的控制量,当偏差小于某一阈值时,切换到PID控制以消除系统的静态误差,较好地克服了传统PID控制和普通模糊控制所存在的主要问题.通过仿真实验分析,证明了该控制方法的有效性.     

最优PID控制器在智能人工腿中的应用

以蚁群算法为基础,提出了一种新的非线性PID控制器及其参数优化设计方法;该控制器是基于PID控制器各增益参数与误差信号之间呈现非线性关系,根据一般控制系统的阶跃响应曲线,在不同响应时间阶段PID三个增益调节参数的理想变化情况,提出根据控制信号与误差、误差变化率之间的调节规律,拟合一组增益参数的非线性函数,并利用蚁群算法搜索出一组最优的非线性PID参数,构造最优非线性PID控制器,称为AS-NLPID控制器;该控制器已被用于CIP-Ⅰ智能人工腿;仿真实验证实AS-NLPID控制器能有效地控制CIP-Ⅰ智能人工腿,并具有良好的动态和稳态性能.     

PID控制器改进方法研究

分析了常规PID(比例—积分—微分)控制特点,针对其在非线性控制中存在的问题,基于参数自整定和控制器误差组合方式,分别设计了参数自整定模糊PID控制器、参数自整定RBF神经网络PID控制器和非线性自抗扰PD控制器.并进行了实验验证,实验结果表明,从参数自整定和控制器误差组合角度出发,所采用的控制策略可使非线性系统具有较好的动态特性、鲁棒性和自适应能力.     

基于粒子群算法的一种非线性PID控制器

基于PID控制器各增益参数与偏差信号之间非线性关系，分析了一种P／I／D各部分参数关于误差的理想变化过程，根据控制与误差之间的调节规律，给定一组增益参数的连续非线性函数，构造出一种非线性PID控制器。粒子群算法具有对整个参数空间进行高效并行搜索的特点，采用该算法寻优整定该非线性PID控制器的各增益参数。仿真结果表明了所提算法的有效性和所设计控制器的优越性能。     

基于粒子群算法的一种非线性PID控制器

基于PID控制器各增益参数与偏差信号之间非线性关系,分析了一种P/I/D各部分参数关于误差的理想变化过程,根据控制与误差之间的调节规律,给定一组增益参数的连续非线性函数,构造出一种非线性PID控制器。粒子群算法具有对整个参数空间进行高效并行搜索的特点,采用该算法寻优整定该非线性PID控制器的各增益参数。仿真结果表明了所提算法的有效性和所设计控制器的优越性能。     

基于感知模糊自适应蚁群算法的非线性PID控制

随着系统复杂度的提高和对象不确定性因素的增加,为克服线性PID动态性能和稳态性能差的缺陷,分析了非线性PID控制器各控制参数对误差的理想变化过程,构造非线性PID控制器。由于增益参数大量增加,传统参数优化方法不再适用,在分析蚁群算法的基础上,提出了基于感知自适应蚁群算法,并加入模糊自适应信息素更新机制,用于优化非线性PID控制器的设计方法。通过仿真实验将该控制器与基于蚁群算法的非线性PID控制器和基于蚁群算法、Z-N法的PID控制器进行对比,并对控制性能和收敛性能进行了分析,结果表明该算法有效克服了传统蚁群算法收敛速度较慢、容易陷入局部最优而停滞的缺陷,该控制器具有更好的动态性能和稳态性能。     

Adaptive hierarchical tuning of fuzzy controllers

Fuzzy controller design includes both linear and non-linear dynamic analysis. The knowledge base parameters associated within the fuzzy rule base influence the non-linear control dynamics while the linear parameters associated within the fuzzy output signal influence the overall control dynamics. For distinct identification of tuning levels, an equivalent linear controller output and a normalized non-linear controller output are defined. A linear proportional-integral-derivative (PID) controller analogy is used for determining the linear tuning parameters. Non-linear tuning is derived from the locally defined control properties in the non-linear fuzzy output. The non-linearity in the fuzzy output is then represented in a graphical form for achieving the necessary non-linear tuning. Three different tuning strategies are evaluated. The first strategy uses a genetic algorithm to simultaneously tune both linear and non-linear parameters. In the second strategy the non-linear parameters are initially selected on the basis of some desired non-linear control characteristics and the linear tuning is then performed using a trial and error approach. In the third method the linear tuning is initially performed off-line using an existing linear PID law and an adaptive non-linear tuning is then performed online in a hierarchical fashion. The control performance of each design is compared against its corresponding linear PID system. The controllers based on the first two design methods show superior performance when they are implemented on the estimated process system. However, in the presence of process uncertainties and external disturbances these controllers fail to perform any better than linear controllers. In the hierarchical control architecture, the non-linear fuzzy control method adapts to process uncertainties and disturbances to produce superior performance.     

Efficient control of a 3-link planar rigid manipulator using self-regulated fractional-order fuzzy PID controller

A self-regulated fractional-order fuzzy proportional–integral–derivative (SRFOFPID) controller is proposed to control a highly non-linear, complex and coupled 3-link planar rigid robotic manipulator in a virtual industrial environment. Industrial environment was simulated by introducing different kind of disturbances in the system and sensor noise. Proposed SRFOFPID controller is a direct non-linear adaptive controller having self-regulating feature and has been realized using fractional-order operators i.e. integrator and differentiator in self-regulated integer-order fuzzy PID (SRIOFPID) controller. Gains of SRFOFPID and SRIOFPID controllers are optimized using Backtracking Search Algorithm by minimizing an amalgamation of integral absolute error signal and integral absolute change in control signal as cost function. Performance of SRFOFPID and SRIOFPID controllers are assessed and compared with reference path under virtually simulated industrial environment. Presented intensive simulation studies revealed that both the controllers offered decent reference trajectory tracking performance under nominal operating conditions while SRFOFPID controller offered exceptionally robust performance under industrial scenario and uncertainties. Finally, the stability analysis of overall closed loop system is performed using small gain theorem and necessary and sufficient bounded-input and bounded-output stability conditions are established.     

Some investigations on fuzzy P + fuzzy I + fuzzy D controller for non-stationary process

The paper addresses the adaptive behaviour of parallel fuzzy proportional plus fuzzy integral plus fuzzy derivative (FP+FI+FD) controller. The parallel FP+FI+FD controller is actually a non-linear adaptive controller whose gain changes continuously with output of the process under control. Two non-stationary processes, whose characteristics change with time, are considered for simulation study. Simulation is performed using software LabVIEW TM . The set-point tracking response of parallel FP+FI+FD is compared with conventional parallel proportional plus integral plus derivative (PID) controller, tuned with the Ziegler-Nichols (Z-N) tuning technique. Simulation results show that conventional PID controller fails to track the set-point and becomes unstable as the process changes its characteristic with time. But the parallel FP+FI+FD controller shows considerably much better set-point tracking response and does not deviate from steady state. Also, a huge spike is observed in the output of PID controller as the reference set-point and process parameters are changed, while the FP+FI+FD controller gives spike free control signal.     

非线性系统的模糊免疫PSD控制与仿真

针对模糊免疫PID控制算法中微分与积分增益不能根据系统特性自动调整的问题,提出了一种模糊免疫PSD(Proportional Summation Derivative)控制算法。该方法将自适应PSD算法与模糊免疫PID算法相结合,利用自适应PSD控制算法根据过程误差的几何特性建立的PSD控制规律,使得模糊免疫PID控制算法中的微分和积分增益可以随比例增益的变化而自适应调整,从而进一步提高控制算法的自适应性能。仿真实验表明,采用该算法可以提高非线性、时变系统的控制性能,并能减少参数调整的工作量。     

非线性动态模糊系统过程控制与稳定性分析

针对自动控制领域中存在的大量的非线性动态模糊系统,提出了非线性动态模糊系统过程控制模型,并给出了动态模糊控制器的设计算法和该模型的稳定性分析,很好地解决了模糊控制系统所不能解决的动态性问题.     

基于最优预测的神经元模糊自整定PID控制

针对工业过程中普遍存在的时滞、非线性、对象参数时变等特性,提出了一种基于最优预测的神经元模糊自整定PID控制算法。该算法利用最优预测克服时滞,利用神经元学习功能和模糊控制调节神经元增益克服系统的非线性和时变问题。仿真结果表明,该控制算法鲁棒性强、响应速度快,具有工业控制应用价值。     

Developments of fuzzy PID controllers

Abstract: This paper describes the development and tuning methods for a novel self-organizing fuzzy proportional integral derivative (PID) controller. Before applying fuzzy logic, the PID gains are tuned using a conventional tuning method. At supervisory level, fuzzy logic readjusts the PID gains online. In the first tuning method, fuzzy logic at the supervisory level readjusts the three PID gains during the system operation. In the second tuning method, fuzzy logic only readjusts the proportional PID gain, and the corresponding integral and derivative gains are readjusted using the Ziegler–Nichols tuning method while the system is in operation. For the compositional rule of inferences in the fuzzy PID and the self-organizing fuzzy PID schemes two new approaches are introduced: the min implication function with the mean of maxima defuzzification method, and the max-product implication function with the centre of gravity defuzzification method. The fuzzy PID controller, the self-organizing fuzzy PID controller and the PID controller are all applied to a non-linear revolute-joint robot arm for step input and path tracking experiments using computer simulation. For the step input and path tracking experiments, the novel self-organizing fuzzy PID controller produces a better output response than the fuzzy PID controller; and in turn both controllers exhibit better process output than the PID controller.     

基于GSAGA的模糊PID控制在自动油门系统中的应用研究

针对现代民用飞机非线性和时变的特点,设计了一种用于民机自动油门控制系统的模糊PID控制器;模糊控制器以速度跟踪误差及其微分信号作为输入调节PID控制器的比例、积分及微分参数,进而控制油门开度以调节发动机推力,最终实现对速度的控制;文中进一步采用广义自适应遗传算法(GSAGA)对模糊PID控制器的输出因子进行优化,在着陆模态下采用所设计的优化控制策略与传统模糊PID控制进行了对比仿真,仿真结果显示,在民机自动油门控制系统中基于GSAGA的模糊PID控制器的控制效果优于传统模糊控制方法,仿真结果符合飞行品质指标,控制效果良好。     

无刷直流电动机积分反演模糊滑模控制

针对普通的无刷直流电动机控制策略受电动机本身因素影响,难以达到理想效果的问题,介绍了一种积分反演自适应滑模变结构控制和模糊控制相结合的控制器。该控制器在滑模面中加入积分项,实现了对速度信号的无静差跟踪,提高了系统的稳态精度;用模糊控制器来解决切换控制增益设定只能靠经验的问题;采用模糊控制算法对不确定性进行估计,有效地减小了滑模控制方法带来的抖振;为了进一步提高控制性能,重新设计了趋近律。仿真结果表明,该控制器能够大幅提升无刷直流电动机控制系统的性能。