一种模糊-PI双模控制系统的仿真与设计

为了提高系统的控制性能,综合了模糊控制和PID控制的优点,提出一种基于模糊-PI双模控制器设计方法。典型的二维模糊控制器因缺少积分环节,难以消除稳态误差,控制的精度常常不能满足系统要求;而PI控制器具有良好的消除稳态误差的作用,所以将其与模糊控制器结合构成复合控制器。通过Matlab/Simulink仿真,结果表明,与经典的PID控制方式相比较,该控制方式在快速性、稳态性及准确性方面都有较大提高。     

Adaptive fuzzy proportional integral power control for a cellularCDMA system with time delay

We investigate the use of fuzzy logic control techniques for adaptive power control in a direct-sequence code-division multiple-access (DS/CDMA) cellular system over the mobile fading radio channels with propagation time delay. A fuzzy PI (proportional-plus-integral) control whose input variables are the received power error and error change is introduced to determine each user transmitting power in order to simultaneously equalize all users' signal powers received at the base station and achieve better system stability and control performance. This control strategy can ensure long loop transmission delays without causing the system to become unstable. According to the well-known phase-plane method, the derivation of the fuzzy PI control has been carried out by analyzing the response areas, cross-over, and extreme points of the system step response with apriori knowledge of the dynamics of the CDMA mobile fading channels. For a long time-delay fading process, a methodology is developed to modify the rule base to contain the delay information for reducing the deadtime effects of the process. Moreover, the additional advantages of fuzzy PI control over conventional control theories are: increased robustness in spite of interference and the ability to handle the time-delay process whose parameters are not accurately known. Simulation results show that a good performance can be achieved both in RMS tracking error and traffic capacity by use of fuzzy PI power control, especially in poor interuser interference and long time delay conditions     

具有神经网络前馈控制器的污水处理模糊控制系统设计

为解决污水处理过程中非线性、大时滞及干扰严重的问题,提出一种将模糊控制器和前馈控制器相接合的控制方法。其中在建立前馈控制器时,提出了使用神经网络建立前馈控制器的新方法。使用这种方法建立前馈控制器无需建立控制系统控制通道和干扰通道的数学模型,也不要求干扰是可以测量的。在MATLAB环境下对控制系统进行仿真,结果表明,将模糊控制和前馈控制结合可以有效克服干扰,提高系统的稳态精度;基于神经网络的前馈控制器可以有效补偿污水处理过程中的干扰,具有实际意义。     

适用于AFM的数字智能反馈控制器设计

原子力显微镜(AFM)是进行纳米测量和操作的一种重要工具.近年来,纳米科技的迅速发展使得传统AFM越来越无法满足纳米测量快速和高分辨率的测试需求,而反馈控制器的速度是限制AFM成像速度和分辨率的关键因素之一.为此,本文搭建基于高速数字信号处理器(DSP)的数字反馈控制系统,将模糊控制算法与比例积分PI控制算法结合,利用模糊规则自动选择合适的比例和积分参数,改善Z向反馈系统的鲁棒性.基于自制的AFM系统,将该方法与传统PI控制算法进行对比实验,在相同的扫描条件下,该数字智能反馈控制器可在扫描范围为30μm×30μm时,将AFM的行扫描速度由3 Hz提高到40 Hz,验证了该方法能够有效改善AFM的扫描速度和成像分辨率.     

基于模糊推理的人工气候室温度PID控制器参数的整定

具有较大容积的人工气候室温度控制是一个典型的大时滞、非线性复杂控制问题,应用基于模型的控制理论来进行分析和综合非常困难。运用模糊数学的基本理论和方法,提出了一种基于模糊推理的PID控制器参数自动整定方法。该方法将难以定量描述的参数调整经验用模糊集合来表示,并把对应的模糊推理规则作为知识存入控制器中,控制器根据控制系统的实际运行情况,在实现对PID参数的自动调整。实验表明,提出的模糊PID控制器参数整定方法,适合于具有较大可控率的人工气候室温度控制系统设计,在同类控制系统设计中具有先进性。     

模糊控制在异步电机直接转矩控制系统中的应用

为提高异步电机直接转矩控制系统的低速性能,本文中提出了一种模糊控制和PI闭环校正磁链观测器相结合的控制方法。该方法采用PI闭环校正磁链观测器代替传统U-I模型,给磁链和转矩误差分级,用模糊控制代替传统滞环控制选择合适的电压矢量．为减少模糊控制规则和加快模糊推理,定义了定子磁链角映射。仿真结果表明,此方法能够提高磁链的观...     

T-S fuzzy controllers for nonlinear interconnected systems with multiple time delays

This paper investigates the effectiveness of a passive tuned mass damper (TMD) and fuzzy controller in reducing the structural responses subject to the external force. In general, TMD is good for linear systems. We proposed here an approach of Takagi-Sugeno (T-S) fuzzy controller to deal with the nonlinear system. To overcome the effect of modeling error between nonlinear multiple time-delay systems and T-S fuzzy models, a robustness design of fuzzy control via model-based approach is proposed in this paper. A stability criterion in terms of Lyapunov's direct method is derived to guarantee the stability of nonlinear multiple time-delay interconnected systems. Based on the decentralized control scheme and this criterion, a set of model-based fuzzy controllers is then synthesized via the technique of parallel distributed compensation (PDC) to stabilize the nonlinear multiple time-delay interconnected system and the H/sup /spl infin// control performance is achieved at the same time. Finally, the proposed methodology is illustrated by an example of a nonlinear TMD system.     

基于模糊预测控制的船舶动力定位系统的设计

在系统分析和研究船舶动力定位系统的基础上,提出一种基于模糊预测控制的船舶动力定位的方法,设计了模糊预测控制器。首先,在预测控制部分,探讨预测模型和反馈校正的设计;在模糊控制部分,研究隶属函数和模糊规则的具体制定。最后采用工程数据,对该算法和模糊预测控制器进行了仿真验证和性能评判,结果表明,所设计的控制器能对船舶进行有效的定位。     

自适应模糊PID控制器在供水系统中的仿真研究

对于恒压供水的复杂控制系统,常规的PID控制器难以保证系统在任何工况条件下始终具有较好的控制性能。将模糊控制理论应用于供水系统,设计出了一种自适应模糊PID控制器,通过仿真实验表明:在恒压供水系统中,自适应模糊PID控制较传统PID控制具有更好的静态和动态特性。     

Digital Controller Design for Analog Systems Represented by Multiple Input–Output Time-Delay Transfer Function Matrices with Long Time Delays

This paper presents a digital controller design methodology for multivariable analog systems represented by minimally realizable multiple input–output time-delay transfer function matrices with long time delays. First, the analog transfer function matrix with multiple input–output time delays is minimally realized and represented by a delay-free state-space model and a multiple output-delay function. For a specific multiple time-delay transfer function matrix with complex poles, a minimal realization scheme is newly proposed. Then the minimized delay-free state-space model is utilized for linear quadratic regulator (LQR) design. Furthermore, the designed analog LQR is digitally redesigned via a predictive state-matching method for finding a low-gain digital controller from the pre-designed high-gain analog controller. For implementation of the digitally redesigned controller, a digital observer is constructed for the multiple time-delay system with long time delays. An illustrative example is given to demonstrate the effectiveness of the proposed method.     

环境试验设备系统的一种温度改进控制方案研究

针对典型环境试验设备的温度控制方法进行了研究,给出了相应的改进控制方案。该方案结合模糊控制,模糊PID控制与实时辨识的Smith预估器为一体,达到了良好的控制效果。     

一种基于时滞辨识的模糊Smith控制

利用信号处理中的互相关技术可以对声发射波之间的时间延迟进行测量的功能,实现对变化的时滞参数的跟踪,并将其同模糊控制以及Smith预估控制相结合,形成了一种基于时滞辨识的模糊Smith控制算法,对此算法进行仿真研究。仿真结果证明了此算法的有效性。     

电压模式Buck-Boost变换器变论域模糊PI控制

电压模式Buck-Boost变换器是一个典型的非最小相位系统。根据DC-DC Buck-Boost变换器的工作特性,运用状态空间平均法建立其小信号模型,据此设计PI控制器参数。Buck-Boost变换器是一个时变的非线性系统,传统PI控制难以达到最优的控制效果,由此采用模糊PI控制来规避PI控制的弊端。针对模糊PI控制在被控量变化较大时,控制精确度变差的问题,设计了模糊论域自适应伸缩变化的变论域模糊PI控制器,对Buck-Boost电路进行控制。通过Matlab/Simulink环境仿真,实验结果表明,变论域模糊PI控制具有更好的动态控制性能。     

基于模糊控制的感应电机直接转矩控制系统

根据直接转矩控制理论,在Matlab 6.5/Simulink下构造了一个感应电机直接转矩控制系统的仿真模型。为改善感应电机系统的动、静态品质,设计了模糊自适应PI速度调节器,根据速度偏差与偏差变化率,通过模糊推理在线调整PI参数,提高系统的调速性能。仿真结果表明,这种模糊控制器具有比常规PID控制器更好的控制效果。     

Fuzzy control of mean arterial pressure in postsurgical patientswith sodium nitroprusside infusion

We developed a fuzzy control system to provide closed-loop control of mean arterial pressure (MAP) in postsurgical patients in a cardiac surgical intensive care unit setting by regulating sodium nitroprusside (SNP) infusion. The fuzzy controller, originally expert-system-based, was analytically converted to ten nonfuzzy control algorithms, which reduced execution time dramatically. The core of the control algorithms was a nonlinear proportional-integral (PI) controller whose proportional gain and integral gain adjusted continuously according to error and rate change of error of the process output. The gains became larger when process output was far from desired setpoint and smaller when process output was close to desired setpoint, resulting in more dynamic and stable control performance than the regular PI controller, especially when a linear process with time-delay or a nonlinear process was involved. The control algorithms, encoded in C programming language, were implemented to control MAP in patients. Preliminary clinical results showed that the average percentage of time in which MAP stayed between 90% and 110% of the MAP setpoint was 89.31%, with a standard deviation of 4.96%. These were calculated based on 12 patient trials, with total trial time of 95 and 13 min.     

自调整模糊控制器在永磁同步电机矢量控制中的应用

模糊控制器对系统模型依赖程度低,性能优异,已经在许多场合得到了应用。传统的永磁同步电机矢量控制系统采用PI控制,在电机参数变化或负载波动较大时性能不佳。针对这一问题,本文设计了一种基于量化因子和比例因子自调整的自适应模糊控制器。仿真结果表明,与传统PI和基本模糊控制器相比,这种参数自调整模糊控制器能使系统具有更好的抗扰性和更优良的稳态性能。     

怠速模糊控制算法的研究

在研究传统PID控制算法在发动机怠速应用的基础上,提出了模糊怠速控制策略。在基于MATLAB/SIMULINK的仿真工具上,设计出了发动机怠速系统,并在此基础上设计出了模糊控制器。仿真过程中,研究了模糊控制算法的对怠速的控制能力,包括发动机启动到真正怠速的响应速度,以及发动机在外部负荷变化情况下的响应能力,随时增加负荷或者是减小负荷,模糊控制器都能做出快速响应。实验表明:模糊控制器的抗干扰能力相对PID有了很大的提高,由于不需要精确地数学模型,发动机具有了较强的自适应能力。     

Smith-PID在空气源热泵热水供应系统中的应用

热水供热过程具有大惯性、纯滞后和非线性的特性.Smith预估算法能有效克服纯滞后的问题,而PID控制能提高系统的稳定性和精度性.针对它的这些特点,本文把Smith补偿原理和PID控制方法结合起来,提出一种应用在空气源热泵热水供应系统的Smith-PID控制方法.通过编程仿真结果表明,新的控制方案与传统的PID控制相比,本算法具有良好的控制品质,它不仅具有满意的控制性能,而且响应速度得到了提高,缩小了超调.在实际的工程中有一定的应用价值.     

Robust loop shaping-fuzzy gain scheduling control of a servo-pneumatic system using particle swarm optimization approach

In this paper, a new technique called robust loop shaping-fuzzy gain scheduled control (RLS-FGS) is proposed to design an effective nonlinear controller for a long stroke pneumatic servo system. In our technique, a nonlinear dynamic model of a long stroke pneumatic servo plant is identified by the fuzzy identification method and is used as the plant for our design. The structure of local controllers is selected as PID control which is proven by many research works that this type of control has many advantages such as simple structure, well understanding, and high performance. The proposed technique uses particle swarm optimization (PSO) to find the optimal local controllers which maximize the average stability margin. In addition, performance weighting function which is normally difficult to obtain is automatically determined by PSO. By the proposed technique, the RLS-FGS controller can be designed, and the structure of local controllers is still not complicated. As seen in the simulation and experimental results, our proposed technique is better than the classical gain scheduled PID controller tuned by pole placement and the conventional fuzzy PID controller tuned by ISE method in terms of robust performance.     

基于发动机平均值模型的控制仿真

针对发动机平均值模型进行控制仿真以验证所设计的控制策略对发动机控制的有效性,首先在MATLAB／Simulink中建立发动机的平均值模型,其次分别建立PID控制器和模糊PID控制器对发动机平均值模型进行控制仿真,最后对两种控制器的仿真结果进行比较分析。通过最后的仿真结果可以看出两种控制器都可以稳定控制发动机模型,但模糊PID控制器具有更好的控制效果。发动机是一个非线性、时滞的动力学系统,而模糊控制不需要了解被控对象的特性,故它能精确控制发动机模型。