基于量子粒子群的斜坡上两轮移动机器人的广义二型模糊控制

两轮移动机器人(2WMR)本身具有多变量和非线性等特征,从而使其控制变得复杂。当2WMR在倾斜的表面上移动时,控制问题变得更加复杂。针对2WMR的非线性模型,设计2WMR的广义二型模糊逻辑平衡控制器和位置控制器。针对广义二型模糊逻辑控制器(GT2FLC)中前、后件中参数难以设定的问题,通过量子粒子群算法(QPSO)优化隶属函数中的参数。针对GT2FLC和区间二型模糊逻辑控制器(IT2FLC)在不同斜面上对移动2WMR的平衡和位置控制的效果进行进一步的对比分析,并干扰对控制效果的影响。仿真结果表明,GT2FLC具有更好的抗干扰能力。     

基于SelQPSO的WMR区间二型模糊逻辑控制

针对轮式移动机器人(WMR)的轨迹跟踪问题,首先根据WMR非线性模型设计了区间二型模糊逻辑控制器(Ⅱ2FLC);其次针对IT2FLC模糊规则中隶属函数参数难以确定问题,通过改进的量子粒子群算法(SelQPSO)优化IT2FLC的隶属函数参数.最后,将经过SelQPSO优化的IT2FLC控制效果分别与经过量子粒子群算法(QPSO)优化的IT2FLC、未经优化的IT2FLC以及T1FLC算法进行对比.此外,进一步考虑外部扰动分别对四种控制方法控制效果的影响.仿真结果表明,与另外三种控制方法相比,经过SelQPSO优化的IT2FLC具有更好的控制效果和抗干扰能力.     

基于改进QPSO的两轮移动机器人区间二型模糊逻辑控制

以两轮移动机器人(TWMR)为对象,针对机器人的非线性模型分别设计控制机器人平衡和位置的区间二型模糊逻辑控制器(IT2 FLC).针对区间二型模糊规则中参数难以设定的问题,通过改进的量子粒子群算法(LTQPSO)优化区间二型模糊集参数,并给出优化算法的流程图.针对区间二型模糊逻辑控制器和一型模糊逻辑控制器(T1 FLC)对平衡和位置的控制效果进行对比.进一步考虑质量不确定和位置扰动对两种控制器控制效果的影响.仿真结果表明,IT2 FLC可以有效地达到设定的控制目标,与T1 FLC相比,IT2 FLC拥有更好的处理不确定性的能力以及更强的抗扰动能力.     

Type-2 fuzzy control for a flexible-joint robot using voltage control strategy

Type-1 fuzzy sets cannot fully handle the uncertainties. To overcome the problem, type-2 fuzzy sets have been proposed. The novelty of this paper is using interval type-2 fuzzy logic controller (IT2FLC) to control a flexible-joint robot with voltage control strategy. In order to take into account the whole robotic system including the dynamics of actuators and the robot manipulator, the voltages of motors are used as inputs of the system. To highlight the capabilities of the control system, a flexible joint robot which is highly nonlinear, heavily coupled and uncertain is used. In addition, to improve the control performance, the parameters of the primary membership functions of IT2FLC are optimized using particle swarm optimization (PSO). A comparative study between the proposed IT2FLC and type-1 fuzzy logic controller (T1FLC) is presented to better assess their respective performance in presence of external disturbance and unmodelled dynamics. Stability analysis is presented and the effectiveness of the proposed control approach is demonstrated by simulations using a two-link flexible-joint robot driven by permanent magnet direct current motors. Simulation results show the superiority of the IT2FLC over the T1FLC in terms of accuracy, robustness and interpretability.     

基于APSO的GIS腔体移动机器人区间二型模糊跟踪控制

为解决气体绝缘封闭开关设备(GIS)腔体移动机器人的轨迹跟踪控制问题，提出一种基于优化算法的麦克纳姆轮全向移动机器人(MWOR)区间二型模糊跟踪系统。建立MWOR在腔体中的非线性模型，并设计相应的区间二型模糊逻辑控制器(IT2FLC);针对IT2FLC隶属度函数难以确定的问题，采用自适应粒子群优化(APSO)算法对隶属度函数进行优化。分别对MWOR在无扰动和有扰动时进行直线和圆轨迹跟踪的仿真实验。结果表明，该方法对MWOR具有很好的控制效果和抗干扰效果。     

结合融合函数的双轮机器人二型模糊控制

针对双轮自平衡机器人的运动控制,设计了区间二型模糊逻辑控制器(T2FLC),提出函数融合的方法,解决模糊控制器规则繁杂的问题。首先对双轮机器人进行运动学建模,针对机器人的数学模型,设计双闭环二型模糊自适应PID控制器,分别控制机器人的直立平衡和行走速度。将机器人的反馈变量进行函数融合,简化T2FLC的模糊规则。对设计的控制器进行仿真,结果表明T2FLC比PID控制器具有更快的响应速度。进一步考虑输入扰动和机器人数学模型参数不确定对控制器的影响,仿真表明T2FLC具有更好的抗干扰能力和更强的鲁棒性。     

具有极点约束的空天飞行器再入姿态的H∞模糊保性能控制

提出一种新的模糊鲁棒控制方法,并应用于空天飞行器(aerospace vehicle, ASV) 再入段姿态的控 制器设计．首先基于ASV 再入姿态动态系统的T-S 模糊模型,考虑外界干扰和系统的不确定性,考察了姿态 角速率和姿态角的镇定问题,然后结合极点约束,导出了具有极点约束的H∞模糊保性能控制律存在的条件． 最后设计了ASV 再入姿态的模糊鲁棒控制器,应用Matlab 的LMI(linear matrix inequality) 和FLC(fuzzy logic control) 工具可得出控制器的解．仿真结果验证了算法的有效性．     

基于LabVIEW的模糊控制器设计与仿真

以LabVIEW编程软件为基础,介绍了其中控制模块中模糊逻辑工具包(Fuzzy LogicToolkit)中的子程序(VI),并应用其中模糊逻辑控制器设计VI构建模糊控制器的方法。设置隶属度函数,建立模糊控制规则,创建模糊推理关系,实现对模糊控制器设计的具体步骤,并结合电液伺服模糊控制系统实例,利用模糊逻辑(Fuzzy logic)模块及LabVIEW提供的仿真模块(Simulation Module)建立系统仿真框图。通过仿真曲线,分析模糊控制器控制效果及其影响因素,从而大大缩短模糊控制器的设计周期,具有较大的工程实用价值。     

基于独立神经元的自适应主动队列管理算法

针对主动队列管理中PI(Proportional-integral)算法的不足,设计了一种基于独立神经元的自适应PI控制器INAPI(Independent neurons-based adaptive PI controller).控制器利用神经网络理论中的神经元模型与学习算法,2个独立的神经元根据系统状态采用最速下降法在线调整PI控制器的控制参数,以适应动态变化的网络参数.仿真结果表明,INAPI的性能要优于使用固定控制参数的PI和FLC(Fuzzy logic controller)算法.     

广义区间二型模糊集合的词计算

普通的模糊集合是点值为二维的一型模糊集合,二型模糊集合(Type-2 fuzzy sets, T2 FS)是点值为三维的模糊集合, T2 FS比相应的一型难以理解和计算. 为了让人们更好地理解T2 FS并推广其应用, 本文提出了广义区间二型模糊集合(Generalized interval type-2 fuzzy sets, GIT2 FS)的定义, 并将其分成三类:离散型、半离散型及连续型,分别给出相应的数学表达式与扩展原理公式,并得到了GIT2 FS在两种不同的模糊逻辑算子下的词计算.     

Genetic learning and performance evaluation of interval type-2 fuzzy logic controllers

Type-2 fuzzy sets, which are characterized by membership functions (MFs) that are themselves fuzzy, have been attracting interest. This paper focuses on advancing the understanding of interval type-2 fuzzy logic controllers (FLCs). First, a type-2 FLC is evolved using Genetic Algorithms (GAs). The type-2 FLC is then compared with another three GA evolved type-1 FLCs that have different design parameters. The objective is to examine the amount by which the extra degrees of freedom provided by antecedent type-2 fuzzy sets is able to improve the control performance. Experimental results show that better control can be achieved using a type-2 FLC with fewer fuzzy sets/rules so one benefit of type-2 FLC is a lower trade-off between modeling accuracy and interpretability.     

A comparative experimental study of type-1/type-2 fuzzy cascade controller based on genetic algorithms and particle swarm optimization

In this study, we introduce the design methodology of an optimized fuzzy controller with the aid of particle swarm optimization (PSO) for ball and beam system.The ball and beam system is a well-known control engineering experimental setup which consists of servo motor, beam and ball. This system exhibits a number of interesting and challenging properties when being considered from the control perspective. The ball and beam system determines the position of ball through the control of a servo motor. The displacement change of the position of ball leads to the change of the angle of the beam which determines the position angle of a servo motor.The fixed membership function design of type-1 based fuzzy logic controller (FLC) leads to the difficulty of rule-based control design when representing linguistic nature of knowledge. In type-2 FLC as the expanded type of type-1 FL, we can effectively improve the control characteristic by using the footprint of uncertainty (FOU) of the membership functions. Type-2 FLC exhibits some robustness when compared with type-1 FLC.Through computer simulation as well as real-world experiment, we apply optimized type-2 fuzzy cascade controllers based on PSO to ball and beam system. To evaluate performance of each controller, we consider controller characteristic parameters such as maximum overshoot, delay time, rise time, settling time, and a steady-state error. In the sequel, the optimized fuzzy cascade controller is realized and also experimented with through running two detailed comparative studies including type-1/type-2 fuzzy controller and genetic algorithms/particle swarm optimization.     

A type-2 fuzzy logic controller design for buck and boost DC–DC converters

Conventional (type-1) fuzzy logic controllers have been commonly used in various power converter applications. Generally, in these controllers, the experience and knowledge of human experts are needed to decide parameters associated with the rule base and membership functions. The rule base and the membership function parameters may often mean different things to different experts. This may cause rule uncertainty problems. Consequently, the performance of the controlled system, which is controlled with type-1 fuzzy logic controller, is undesirably affected. In this study, a type-2 fuzzy logic controller is proposed for the control of buck and boost DC–DC converters. To examine and analysis the effects of the proposed controller on the system performance, both converters are also controlled using the PI controller and conventional fuzzy logic controller. The settling time, the overshoot, the steady state error and the transient response of the converters under the load and input voltage changes are used as the performance criteria for the evaluation of the controller performance. Simulation results show that buck and boost converters controlled by type-2 fuzzy logic controller have better performance than the buck and boost converters controlled by type-1 fuzzy logic controller and PI controller.     

Type-2 fuzzy multi-intersection traffic signal control with differential evolution optimization

This paper proposes a multi-agent type-2 fuzzy logic control (FLC) method optimized by differential evolution (DE) for multi-intersection traffic signal control. Type-2 fuzzy sets can deal with models’ uncertainties efficiently because of its three-dimensional membership functions, but selecting suitable parameters of membership functions and rule base is not easy. DE is adopted to decide the parameters in the type-2 fuzzy system, as it is easy to understand, simple to implement and possesses low space complexity. In order to avoid the computational complexity, the expert rule base and the parameters of membership functions (MF) are optimized by turns. An eleven-intersection traffic network is studied in which each intersection is governed by the proposed controller. A secondary layer controller is set in every intersection to select the proper phase sequence. Furthermore, the communication among the adjacent intersections is implemented using multi-agent system. Simulation experiments are designed to compare communicative type-2 FLC optimized by DE with type-1 FLC, fixed-time signal control, etc. Experimental results indicate that our proposed method can enhance the vehicular throughput rate and reduce delay, queue length and parking rate efficiently.     

Control of a distillation column by type-2 and type-1 fuzzy logic PID controllers

The aim of this paper is to develop a type-1 and a type-2 fuzzy logic PID controller (type-1 FLC and type-2 FLC, respectively) for the control of a binary distillation column, the mathematical model of which is characterized by both high nonlinearities and parameter uncertainties. Attention was focused on the tuning procedure proposed by the authors and representing a development of the original Jantzen [1] method for type-1 and type-2 fuzzy controllers, in particular including input type-2 Gaussian membership functions. A theoretical explanation of the differences in fuzzy controller performance was in fact provided in the light of simulation results. The performance of a type-1 FLC was then compared in simulation with the one of type-2 FLC. All the simulation results confirmed the robustness and the effective control action of each fuzzy controller, with evident advantages for the type-2 FLC.     

Design of interval type-2 fuzzy sliding-mode controller

In this paper, an interval type-2 fuzzy sliding-mode controller (IT2FSMC) is proposed for linear and nonlinear systems. The proposed IT2FSMC is a combination of the interval type-2 fuzzy logic control (IT2FLC) and the sliding-mode control (SMC) which inherits the benefits of these two methods. The objective of the controller is to allow the system to move to the sliding surface and remain in on it so as to ensure the asymptotic stability of the closed-loop system. The Lyapunov stability method is adopted to verify the stability of the interval type-2 fuzzy sliding-mode controller system. The design procedure of the IT2FSMC is explored in detail. A typical second order linear interval system with 50% parameter variations, an inverted pendulum with variation of pole characteristics, and a Duffing forced oscillation with uncertainty and disturbance are adopted to illustrate the validity of the proposed method. The simulation results show that the IT2FSMC achieves the best tracking performance in comparison with the type-1 Fuzzy logic controller (T1FLC), the IT2FLC, and the type-1 fuzzy sliding-mode controller (T1FSMC).     

A hierarchical type-2 fuzzy logic control architecture for autonomous mobile robots

Autonomous mobile robots navigating in changing and dynamic unstructured environments like the outdoor environments need to cope with large amounts of uncertainties that are inherent of natural environments. The traditional type-1 fuzzy logic controller (FLC) using precise type-1 fuzzy sets cannot fully handle such uncertainties. A type-2 FLC using type-2 fuzzy sets can handle such uncertainties to produce a better performance. In this paper, we present a novel reactive control architecture for autonomous mobile robots that is based on type-2 FLC to implement the basic navigation behaviors and the coordination between these behaviors to produce a type-2 hierarchical FLC. In our experiments, we implemented this type-2 architecture in different types of mobile robots navigating in indoor and outdoor unstructured and challenging environments. The type-2-based control system dealt with the uncertainties facing mobile robots in unstructured environments and resulted in a very good performance that outperformed the type-1-based control system while achieving a significant rule reduction compared to the type-1 system.