Study on Multi-variables Decoupled Fuzzy Controller for Confined Pig House in Northern China

In winter, the confined pig house of northern China is severe. The environment variables are nonlinear, time-varying and coupled, which seriously affect the health of pigs and the qualities of the meat. In order to solve the problem multi-variables coupling, a multi-variables decoupled fuzzy logic control method was proposed. Two fuzzy logic controllers were designed based on fuzzy logic theory. The fans, heaters and humidifiers were used to control temperature, humidity and ammonia. The reductions of temperature and humidity caused by ventilating were compensated by heaters and humidifiers respectively which realized the multivariables decoupling. The proposed methods were validated through theoretical, experimental and simulation analysis. The results suggested that the methods were able to regulate the confined pig house environment effectively. In addition, comparing to the manual regulation, the proposed methods could reduce 19% power consumption as well.

Fuzzy Model Free Adaptive Control for Rotor Blade Full-Scale Static Testing

To eliminate the node traction coupling during wind turbine blade full-scale static testing,a model free adaptive control algorithm is presented based on fuzzy control performance function compensation. Based on the universal model theory,the fuzzy model free adaptive control( FMFAC) algorithm is designed by configuring the spot static testing experiences as compensation function F( ·). Then the algorithm implementation process is provided and its quick convergence is proved. Using software to establish static load coupling model of multi-nodes,simulate and verify the validity of FMFAC algorithm,which is applied to wind turbines blade full-scale static testing. The results show that the adaptive decoupling ability of FMFAC is better. The traction of four load points can stay steady and change coordinately. Process error is not over ± 6 k N. The error rate is lower than 1% in special phase.This algorithm effectively eliminates the traction coupling of the static testing process,and makes wind turbine blade testing steadily.

Comparative Study of Different Decoupling Schemes for TITO Binary Distillation Column via PI Controller

This paper presents a comparative study of different decoupling control schemes for a two-input, two-output(TITO) binary distillation column via proportional-integral(PI)controller. The key idea behind this paper is designing two novel fuzzy decoupling schemes that depend on human knowledge,instead of the system mathematical model used in conventional decoupling schemes. Based on conventional and inverted decoupling schemes, fuzzy and inverted fuzzy decoupling schemes are developed. The control effect is compared using simulation results for the proposed two schemes with conventional decoupling and inverted decoupling. The proposed fuzzy decoupling schemes are easy to realize and simple to design, besides they have a good decoupling capability. Two methods are used to prove asymptotic stability of each loop and the entire closed-loop system by applying the proposed fuzzy decoupling-based PI controller.The Wood and Berry model of a binary distillation column is used to illustrate the applicability of the proposed schemes.

Research on Robust Control of Nonlinear Fuzzy VSS for Spacecraft

The nonlinear dynamic system of spacecraft with uncertainty and coupling is analyzed and its general dynamical equation is given.The decoupling-ability and controllability are proved.Aiming at this system,a new nonlinear decoupling controlling method is put forward by synthetically using the variable structure and fuzzy theory.The simulation results show that this method is effective in tracking performances under the existence of uncertainty and outer disturbance.

Intelligent coordinated control of power-plant main steam pressure and power output

An intelligent coordinated control strategy has been proposed and successfully applied to a 300MW boiler-turbine unit i. e. Unit 1 of Yuanbaoshan power plant in China. Load following operation of coal-fired boiler-turbine unit in the power plant leads to changes in operating points which result in nonlinear variations of the plant variables and parameters. For the variation of operating condition and slowly varying dynamics, an intelligent control scheme has been developed by combining fuzzy self-tuning with adaptive control and auto-tuning techniques. As there exist strong couplings between control loops of main steam pressure and power output in the unit, a new design for static decoupler aimed at decoupling for setpoints and unmeasured pulverized coal disturbance of the system at the same time is presented. Satisfactory industrial application results show that such a control system has enhanced adaptability and robustness to the complex process, and better control performance and high economic benefit have been obtained.

Logic and logic-based control

This paper gives a matrix expression of logic. Under the matrix expression, a general description of the logical operators is proposed. Using the semi-tensor product of matrices, the proofs of logical equivalences, implications, etc., can be simplified a lot. Certain general properties are revealed. Then, based on matrix expression, the logical operators are extended to multi-valued logic, which provides a foundation for fuzzy logical inference. Finally, we propose a new type of logic, called mix-valued logic, and a new design technique, called logic-based fuzzy control. They provide a numerically computable framework for the application of fuzzy logic for the control of fuzzy systems.

Mathematical Model and Intelligent Control of a Quadcopter, with Non-conventional Membership Functions

This paper shows detailed steps for modeling a quadcopter with Euler-Lagrange equations, followed by controlling it with intelligent control that includes states decoupling. In addition, this control shows non-conventional membership functions for the most instable states, in order to get a fast and effective response.

用Fuzzy-Smith控制策略实现单元机组调节

针对单元机组协调控制对象的非线性、时变和纯迟延的特点,在Smith预测控制的基础上引入了模糊自整定方案,提出了一种单元机组协调控制设计的方法。对某500MW单元机组进行仿真试验,结果表明:这种新的控制方案不仅具有满意的控制性能,而且具有较强鲁棒性和抗干扰性能,它显著提高了协调控制系统在机组负荷工况变化时的适应性和控制品质。

基于Fuzzy-PI混合控制的无刷直流电动机系统

采用了一种基于模糊规则推理的Fuzzy-PI混合控制器用于无刷直流电动机的转速控制中。在分析无刷直流电动机数学模型的基础上,构造了无刷直流电动机控制仿真模块。仿真结果表明,系统超调量小,响应速度快,具有较高的控制精度和较好的鲁棒性。实验结果显示,较之传统PI控制,采用Fuzzy-PI混合控制在无刷直流电动机实时控制中取得了较好的实验效果,具有较好的动态和静态性能。

锅炉燃烧过程的Smith-Fuzzy集成控制

针对模糊控制特点和锅炉燃烧过程的纯滞后、时变、多输入多输出特性 ,进行燃烧过程控制系统的设计。提出主蒸汽压力的Smith -Fuzzy集成控制方案 ,采用具有参数自整定功能的模糊控制器 ,并将解耦原理用于多变量模糊控制系统。仿真结果证明 ,Smith -Fuzzy集成控制比Smith -PID预估控制具有更强的鲁棒性 。

Fuzzy—PID混合控制在乳化炸药油水相流量控制中的应用

阐述了乳化炸药生产线油水相流量配比控制的工艺流程,针对配比控制的非线性、迟延滞后等特点提出了应用Fuzzy-PID的混合控制,简介了混合控制的思路及算法流程,并介绍了模糊控制器的设计过程,最后通过Matlab6.5中的仿真,表明混合控制具有较好的动态性能,又可消除稳态误差,达到了较好的控制效果。

基于Fuzzy-Smith控制器的营养液pH值调控系统研究

pH值的控制是水肥一体化营养液循环控制系统的重要环节,水肥控制过程中pH值在最优控制范围内有利于根系的发育以及多数矿物质的吸收。营养液调控过程中,由于循环管路以及酸液的缓慢扩散,使得pH值调节过程存在很大的时滞,传统PID难以取得良好效果。本研究根据被控对象特点,建立了描述该过程的数学模型,设计开发了一套具有二次混肥特性的以MSP430单片机为主控的营养液pH值控制系统。由于参数自整定模糊PID不需要精确数学模型以及Smith预估可对纯滞后进行补偿的特点,开发的系统将参数自整定模糊PID控制引入Smith预估当中,既缓解了滞后时间对控制系统的影响,又对模型的不精确性进行了补偿。为了验证该算法以及系统的有效性和优越性,分别对PID、Fuzzy-Smith控制算法进行仿真测试,同时在不同灌溉量下进行性能试验。试验结果表明,在不同灌溉量下Fuzzy-Smith控制算法pH值的平均最大超调量为0.83%,营养液pH值从8.0调节为6.0的平均时间为157 s,优于常规PID控制的2.55%和189 s。

基于模糊控制的温室气候控制器设计

为解决猕猴桃基地“瑞玉”新品种苗木繁育中农业大棚温湿度控制精度、速度、稳定性的难题,依托猕猴桃育苗玻璃温室,设计适合农作物生长的环境因子模糊控制系统。该系统针对温室环境中温湿度的强耦合规律,在控制中增加温湿度解耦算法,通过建立不对称温湿度补偿规则库,将温度、湿度模糊控制的输出变量和解耦补偿输出合成后得出实际温湿度控制输出,对农业大棚的温湿度控制过程进行改善,优化大棚环境监控效果。结果表明:空气温度、空气湿度、光照强度控制精度分别达到了±2℃、±5%RH、±200 Lux,达到稳态时间分别为9 min、16 min、4 min,且基本保持稳定,本系统控制精度较高、调节速度快、鲁棒性好,具有较好的实用价值和推广价值。

基于模糊解耦策略的小型注塑机料筒温度F-PI复合控制器

在塑料产品的生产过程中,注塑机料筒温度的响应速度和稳定性对最终塑料产品的质量具有重要影响。为了提高小型注塑机料筒温度的控制精度,针对料筒具有的惯性大、非线性、大滞后、强耦合等温度特性,在模糊控制不能满足控制要求的背景下,提出了基于相邻加热段之间温差的模糊解耦策略,通过利用相邻加热段之间的温差信息,建立模糊解耦控制器,对各段料筒之间的温度耦合进行解耦控制。实验结果表明,该控制方法效果良好,达到目标温度所用时间为1092 s,最大超调量只有3%,但稳态性能较差。为解决稳态性能较差的问题,在模糊解耦的基础上建立F-PI复合控制器,通过引入积分环节消除系统在稳态下的偏差。在Matlab/Simulink环境下进行仿真并在注塑机上进行验证,结果表明,F-PI复合控制方法不仅具有良好的动态响应,还具有更高的稳态精度,稳态偏差仅为±1℃。因此基于模糊解耦策略的F-PI复合控制方法不仅能对料筒的温度耦合进行解耦控制,还有效提高了系统的稳定性和控制精度,具有良好的鲁棒性。

基于BAS的模糊PID解耦算法在船舶动力定位中的应用

模糊PID应用于船舶动力定位控制时,因无法保证量化比例因子选取到最优值可能限制控制性能。基于某动力定位船舶的三自由度运动模型,利用串联补偿解耦算法消除船舶横荡与首摇控制量的相互影响,选取纵荡与横荡的时间乘绝对误差积分(Integrals of Time-weighted Absolute Error,ITAE)之和为目标函数,尝试利用天牛须搜索算法(Beetle Antennae Search algorithm,BAS)对模糊PID中的量化比例因子进行优化。利用Matlab/Simulink,采用PID、模糊PID、基于BAS的模糊PID等3种控制策略,对定点定位工况下动力定位船舶在无干扰和瞬时干扰条件运动响应进行仿真。研究发现,相比于PID和模糊PID,基于BAS的模糊PID在纵荡和横荡运动控制上可显著提高控制精度并减少超调量,进而可改善动力定位系统性能。

基于模糊解耦线性自抗扰控制的混合微电网直流母线电压波动抑制策略

针对由负载突变、扰动加入、系统并网等因素导致的混合微电网直流母线电压波动现象,提出了解耦型线性自抗扰控制策略。首先,根据混合微电网的电路结构建立了混合微电网变换器的数学模型;然后,为提升系统抗扰性对线性自抗扰做解耦处理,形成解耦型线性自抗扰;进一步地,为达到参数实时优化的目的引入模糊自适应优化算法,形成模糊解耦自抗扰控制策略;最后,搭建混合微电网的物理模型与数字模型,进行仿真与半实物仿真实验;结果显示模糊解耦自抗扰控制策略具有优异的直流母线电压波动抑制能力。

基于模糊解耦的坩埚下降法晶体生长炉温度控制系统

针对坩埚下降法晶体生长炉温度控制系统存在的非线性、滞后性、多温区耦合性等问题。设计了模糊解耦控制器来对生长炉上、下两个温区的温度进行控制,该控制器能够根据上、下温区的实时温度误差以及温度误差变化率,调节两个温区加热棒的功率。与传统解耦和PID算法相比,该方法具有不依赖被控对象的精确数学模型,计算量小,算法设计简单等特点。通过仿真将该方法分别与传统PID算法和传统解耦PID算法进行比较,仿真结果表明,该方法具有很好的动态性能、解耦能力和鲁棒性,有利于提升晶体生长炉的控温精度和加热效率。

基于模糊解耦控制的质子交换膜燃料电池阴极控制方法研究

为实现质子交换膜燃料电池(PEMFC)空气子系统流量和压力的协调控制,应用模糊控制原理,采用Mamdani模糊推理方法推理了模糊解耦控制规则,配合MAP前馈控制,组合设计了模糊解耦复合控制器,最后,将其与模糊PID控制器进行对比测试并补充环境适应测试,结果表明,变载工况下模糊解耦控制器的流量控制误差小于±3g/s,压力控制误差小于±10kPa,具有良好的解耦控制效果,同时具有很好的环境适应性。

三相交错并联飞跨电容DC/DC变换器控制策略研究

非隔离型DC/DC变换器具有高效率、低成本、小体积的优势,广泛应用于大功率储能系统。本研究从提升系统输出功率、减少输出电流纹波角度出发,针对拓扑相间均流问题、飞跨电容电压动态响应能力,提出三相交错并联飞跨电容DC/DC变换器控制方案。设计变换器输出与飞跨电容电压控制解耦方法以及整体控制策略,并设计飞跨电容的模糊自整定PI控制器提升其动态响应能力。仿真试验结果表明:所提控制方法可以减少输出电流纹波,实现相间均流。采用模糊自整定PI控制提升了飞跨电容电压控制的动态响应能力。

Multi-parameter decoupling and slope tracking control strategy of a large-scale high altitude environment simulation test cabin

A large-scale high altitude environment simulation test cabin was developed to accurately control temperatures and pressures encountered at high altitudes. The system was developed to provide slope-tracking dynamic control of the temperature–pressure two-parameter and overcome the control difficulties inherent to a large inertia lag link with a complex control system which is composed of turbine refrigeration device, vacuum device and liquid nitrogen cooling device. The system includes multi-parameter decoupling of the cabin itself to avoid equipment damage of air refrigeration turbine caused by improper operation. Based on analysis of the dynamic characteristics and modeling for variations in temperature, pressure and rotation speed, an intelligent controller was implemented that includes decoupling and fuzzy arithmetic combined with an expert PID controller to control test parameters by decoupling and slope tracking control strategy. The control system employed centralized management in an open industrial ethernet architecture with an industrial computer at the core. The simulation and field debugging and running results show that this method can solve the problems of a poor anti-interference performance typical for a conventional PID and overshooting that can readily damage equipment. The steady-state characteristics meet the system requirements.