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.

Stabilization Variable Structure Control for Singular Decoupling Motor System

This paper describes the important application of variable structure control (VSC) theory on induction motor (IM) decoupling control system. A design scheme using singular system variable structure control method for a decoupling IM system is presented. The scheme is shown to be robust to parametric variations and external disturbances. Simulation results show the stability and effectiveness of the proposed scheme

Multivariable Control Performance Assessment Based on Generalized Minimum Variance Benchmark

This paper is concerned with the control performance assessment based on the multivariable generalized minimum variance benchmark.An explicit expression for the feedback controller-invariant(the generalized minimum variance)term of the multivariable control system is obtained,which is used as a standard benchmark for the assessment of the control performance for multi input multi output(MIMO)process.The proposed approach is based on the multivariable minimum variance benchmark.In comparison with the minimum variance benchmark, the developed method is more reasonable and practical for the control performance assessment of multivariable systems.The approach is illustrated by a simulation example and an industrial application.

Genetic Optimization Algorithm of PID Decoupling Control for VAV Air-Conditioning System

Variable-air-volume (VAV) air-conditioning system is a multi-variable system and has multi coupling control loops. While all of the control loops are working together, they interfere and influence each other. A multivariable decoupling PID controller is designed for VAV air-conditioning system. Diagonal matrix decoupling method is employed to eliminate the coupling between the loop of supply air temperature and that of thermal-space air temperature. The PID controller parameters are optimized by means of an improved genetic algorithm in floating point representations to obtain better performance. The population in the improved genetic algorithm mutates before crossover, which is helpful for the convergence. Additionally the micro mutation algorithm is proposed and applied to improve the convergence during the later evolution. To search the best parameters, the optimized parameters ranges should be amplified 10 times the initial ideal parameters. The simulation and experiment results show that the decoupling control system is effective and feasible. The method can overcome the strong coupling feature of the system and has shorter governing time and less over-shoot than non-optimization PID control.

A Broad Range Triboelectric Stiffness Sensor for Variable Inclusions Recognition

With the development of artificial intelligence,stiffness sensors are extensively utilized in various fields,and their integration with robots for automated palpation has gained significant attention.This study presents a broad range self-powered stiffness sensor based on the triboelectric nanogenerator(Stiff-TENG)for variable inclusions in soft objects detection.The Stiff-TENG employs a stacked structure comprising an indium tin oxide film,an elastic sponge,a fluorinated ethylene propylene film with a conductive ink electrode,and two acrylic pieces with a shielding layer.Through the decoupling method,the Stiff-TENG achieves stiffness detection of objects within 1.0 s.The output performance and characteristics of the TENG for different stiffness objects under 4 mm displacement are analyzed.The Stiff-TENG is successfully used to detect the heterogeneous stiffness structures,enabling effective recognition of variable inclusions in soft object,reaching a recognition accuracy of 99.7%.Furthermore,its adaptability makes it well-suited for the detection of pathological conditions within the human body,as pathological tissues often exhibit changes in the stiffness of internal organs.This research highlights the innovative applications of TENG and thereby showcases its immense potential in healthcare applications such as palpation which assesses pathological conditions based on organ stiffness.

On maximum power point tracking control strategy for variable speed constant frequency wind power generation

Based on the characteristic of AC-excited variable speed constant frequency(VSCF)wind power generation,the vector control technique was applied in a doubly fed induction generator(DFIG).Maximum wind energy or maximum output power point can be tracked by decoupling control of active power and reactive power.The research result shows that the net power of generation system delivered to grid in maximum wind energy tracking mode is not the most.We presented a novel maximum power point tracking(MPPT)control strategy by analyzing the DFIG mathematic model and power relations which delivered the maximum power to the grid.The maximum power point could be tracked automatically without measuring wind speed in the control strategy and the control was independent of optimal turbine power curve,which had excellent dynamic and static performances and robustness.Simulation and experimental results testify the accuracy and validity of the control strategy.

Two Second-Order Ecient Numerical Schemes for the Boussinesq Equations

In this paper,we construct two fully decoupled,second-order semi-discrete numerical schemes for the Boussinesq equations based on the scalar auxiliary variable(SAV)approach.By introducing a scalar auxiliary variable,the original Boussinesq system is transformed into an equivalent one.Then we discretize it using the second-order backward di erentiation formula(BDF2)and Crank-Nicolson(CN)to obtain two second-order time-advanced schemes.In both numerical schemes,a pressure-correction method is employed to decouple the velocity and pressure.These two schemes possess the desired property that they can be fully decoupled with satisfying unconditional stability.We rigorously prove both the unconditional stability and unique solvability of the discrete schemes.Furthermore,we provide detailed implementations of the decoupling procedures.Finally,various 2D numerical simulations are performed to verify the accuracy and energy stability of the proposed schemes.

变长分段直线感应电机数学建模

变长分段直线感应电机参数具有不连续、快速时变及强耦合特性,这给电磁暂态建模带来挑战。该文引入3种时变因子推导出具有参数时变特性的变长分段直线感应电机数学表达式。通过分析变长分段直线感应电机定子与动子的电磁耦合特性及时变因子与状态变量之间的耦合关系,建立定子、动子及时变因子相互解耦的数学模型。仿真结果表明,该数学模型计算的电压、电流和速度与有限元计算结果差别小于6%,验证了数学模型的准确性。硬件在环实验结果表明,在高速工况下数学模型可以准确模拟系统的电磁暂态特性,验证了数学模型的解耦能力及数值运算稳定性。

永磁同步电机变频调速系统动态解耦控制方法

常规的永磁同步电机变频调速系统解耦控制,主要采用系统反馈信号完成解耦控制,忽略了反馈信号的预测误差,导致解耦控制结果负荷响应幅值不够稳定.因此,提出永磁同步电机变频调速系统动态解耦控制方法.建立系统数学模型,在该模型中分离系统模式系数获取控制信号,对该信号进行优化处理,基于输出期望值计算预测误差,加权修正预测值,形成动态控制信号,分离有功-无功信号实现动态解耦控制.实验结果表明:所提方法应用后得出的动态解耦控制结果,表现出的负荷响应幅值较为稳定,满足了永磁同步电机变频调速系统的实际解耦控制需求.

基于高频变极性电流源的交叉耦合电弧焊摆动行为抑制

交叉耦合电弧焊工艺理论上可以实现焊接过程中传热、传质解耦和独立控制,具有很大的发展潜力,然而,传统的交叉耦合电弧工艺中旁路电弧电流一般由低频交流焊接热源提供,工作过程中会出现主电弧随着旁路电弧的极性改变而发生电弧摆动现象,使各个电弧之间的热力分配不平衡,传热、传质解耦不彻底.在增材制造应用中,会面临熔滴落点位置不可控、成型精度低等问题,为了解决主电弧的摆动问题,设计开发了旁路电弧为高频变极性电弧的交叉耦合电弧焊接热源.试验结果表明,这种焊接热源可以通过提高旁路电弧的变极性频率,有效地抑制主电弧的摆动行为,进一步实现交叉电弧中填充焊丝熔化速率与工件热输入之间的传热解耦,同时,抑制主电弧摆动后的现象表现为主电弧高频小幅度振动,理论上可以实现对熔池的搅拌作用,利于枝晶破碎、促进焊缝晶粒细化.

A Soft Robotic Fish with Variable-stiffness Decoupled Mechanisms

A Body and/or Caudal Fin （BCF） fish modulate its body stiffness by mechanisms consisting of antagonistic muscles. The mecha- nisms can be considered as Redundant Planar Rotational Parallel Mechanisms （RPRPM） with antagonistic flexible elements. For a typical RPRPM, its stiffness consists of the adjustable stiffness resulting from internal forces and the inherent stiffness caused by inherent com- pliances of flexible elements. In order to decouple the adjustable stiffness from the inherent stiffness and expand the range of stiffness variation, a variable-stiffness decoupled mechanism based on the Mechanically Adjustable Compliance and Controllable Equilibrium Position Actuator （MACCEPA） is presented and used to construct a soft robotic fish with large stiffness variation. According to the analysis of the evolution from RPRPM to MACCEPA, it can be found that MACCEPA is just a special type of RPRPM with only an adjustable stiffness. In addition, MACCEPA existed before RPRPM mechanism. The prototype of the soft robotic fish with variable- stiffness decoupled mechanisms is built to explore the relationships between the body stiffness and the swimming performance. It is validated experimentally that the stiffness variation multiple of the robotic fish is raised, the swimming performance of the robotic fish is improved when the stiffness is modulated to match the driving frequency.

塔里木河流域实际灌溉面积变化及其对陆地水储量的影响分析

塔里木河(简称塔河)流域是典型的干旱绿洲农业区,明晰农业灌溉面积增长对流域水储量的影响,对于维护流域生态环境稳定和可持续发展尤为重要。本文提出了基于作物长势的实际灌溉面积遥感监测方法,采用Landsat卫星影像解译了塔河流域2003—2022年实际灌溉面积,利用相关系数及脱钩指数评价了流域实际灌溉面积变化与水储量的相关和依赖关系。研究结果表明:(1)干旱区灌溉与非灌溉植被长势差异显著,以卫星遥感影像计算的作物生育期内最大植被指数(NDVI)为分类指标,采用随机森林分类器辅以一定数量的样本,可实现大范围年实际灌溉面积的快速提取;(2)塔河流域2003—2022年间实际灌溉面积由2989万亩增加到5420万亩,增长比例为81.33%。5个地州中增长量最大的是阿克苏地区,共增了926万亩,增长比例为87.94%;其次是喀什地区,共增长了668万亩,增长比例为77.44%;(3)从相关系数上看,塔河流域2003—2022年间实际灌溉面积与陆地水储量的相关系数为-0.74,5个地州中阿克苏相关性最高,为-0.96,克州最小,为-0.56;(4)从脱钩指数上看,整个流域灌溉面积的增长强依赖于水储量消耗,虽然依赖度近年来有所降低,但未达脱钩状态。从空间上看,喀什、克州、巴州、阿克苏均为强依赖状态,和田为脱钩状态。上述结果表明,对塔河流域大部分地区而言,如果灌溉效率没有显著提升,灌溉面积已不宜继续扩大。本文的研究结果可为塔里木河流域水资源管理与可持续发展提供参考。

空调压缩机三点式橡胶隔振脚垫刚度优化与实验验证

针对某变频空调压缩机隔振系统性能不达标的问题进行优化设计,采用三点式隔振脚垫布置法搭建空调压缩机隔振系统模型,以橡胶隔振脚垫的刚度为关键优化参量,隔振系统固有频率及能量解耦率为优化目标,获取隔振脚垫刚度对隔振系统振动特性的影响规律及关键参量的最佳匹配方案,并通过隔振脚垫-压缩机系统振动特性测试验证方案的准确性。结果表明,优化后的压缩机橡胶隔振系统性能有较大提高,能够满足实际隔振需求。

基于ISCSO-BP-PID的SMB组分纯度模糊解耦控制方法研究

针对模拟移动床色谱分离系统中存在的强耦合、多变量、非线性和时滞等问题,提出了一种基于改进沙猫群优化算法的BP神经网络自调整PID参数的模拟移动床组分纯度模糊解耦控制方法。该方法首先通过模糊解耦消除了A、B组分纯度控制回路之间的耦合,然后结合改进的沙猫群优化算法和BP神经网络,实现了PID参数的自适应调整,从而有效控制A、B组分的纯度。在改进的沙猫群优化算法中,引入了Cubic混沌映射来初始化沙猫种群,以提高种群分布的均匀性;在搜索猎物阶段加入了可变螺旋搜索策略,使沙猫群拥有更多的搜索路径来调整自身位置;同时,融合了麻雀搜索算法的警戒机制,以加速算法的收敛速度。通过对12个CEC2022测试函数进行验证,证明了改进沙猫群优化算法的有效性。仿真结果表明,所提方法不仅能够有效消除A、B组分纯度控制回路间的耦合效应,而且在各个实际应用场景中均展现出卓越的性能。与传统的PID控制方法相比,在流量突变情况下,调节时间分别缩短了75.40%和77.57%,超调量分别减少了91.84%和81.96%。该方法具备较强的抗干扰能力和良好的鲁棒性,显著改善了整个系统的控制性能。

石油钻机电控系统的多变量解耦控制方式

石油钻机交流电控系统以多变量变频控制多电机为主。针对异步电机非线性、不确定、非最小相等因素引起的耦合多变量无法精确调参及控制的问题,提出了一种石油钻机电控系统的多变量解耦控制方式。在静态坐标系下建立了电机模型,采用了自适应PID神经元网络解耦多变量,降低了速度、励磁等重要变量的耦合程度。高阶非线性部分采用了前馈补偿方法加以消除,低阶非线性部分则加入了神经网络解耦器。通过广义时域响应曲线消除了耦合影响,达到了优化变频控制参数的目的。实验表明,本文所设计的控制方式可以有效地实现多电机速度、励磁等参数的解耦,其控制系统具有良好的稳定性,其闭环控制也具有良好的鲁棒性。

基于子空间的变风量空调解耦控制研究

变风量空调系统的控制回路多,回路间相互耦合,系统模型参数会因外部环境和运行工况等因素而发生变化。针对变风量空调系统控制多回路、长时滞、不确定等特性,提出一种数据驱动的子空间解耦控制策略。该控制策略采用子空间辨识方法在线识别系统状态空间模型,以计算和更新解耦器参数,建立子空间模型,结合子空间模型被控对象输出关于输出的子空间描述和控制器参数的关系式,构建性能指标,完成PID控制器参数的在线整定。对送水流量—送风温度和送风流量—静压耦合回路进行仿真分析,结果表明,子空间解耦控制方法有效消除了耦合回路之间的相互影响,提高了控制系统的稳定性和响应速度。

六边形变换器在全功率抽水蓄能系统中的应用研究

在抽水蓄能系统中,可调速机组可以适应更宽的水头范围,提高机组运行效率。六边形变换器(Hexverter)作为一种高压大容量变换器,可以解决目前变速抽水蓄能系统中变流装置容量小、能量转换效率低以及调速慢等问题。本文提出了基于六边形变换器的全功率抽水蓄能控制系统,对六边形变换器的一般数学模型进行了分析,提出的基于网侧和机侧两种频率的多重解耦控制策略可以实现网侧和机侧功率的控制以及机侧输出电压电流频率灵活可调,基于零序网络的桥臂直流电压平衡控制策略可以实现桥臂直流均压。最后通过仿真和实验验证了六边形变换器在全功率抽蓄系统的应用的有效性。

VAV变风量空调系统施工技术

以某工程为例,对VAV变风量空调系统施工技术进行研究,通过采用BIM技术对风管的形状、构造及布置进行深化设计,优化了系统布置,降低了能耗;采用DDC数字控制的变风量空调系统,实现与计算机联网一体化智能控制,通过VAV末端,实施对空调房间的智能控制,消除了送风温度的变化对室内温度的影响,达到节能的目的。

BTT导弹的变结构解耦控制系统设计

倾斜转弯(Bank-to-Tum,BTT)导弹由于气动外形不对称,以及存在较大的滚动速率,其各个通道之间存在强烈的耦合。本文在变结构控制理论对外界扰动的不变性原理的基础上,采用变结构控制方法设计了BTT导弹的输出解耦控制律。仿真结果验证了本文设计的变结构解耦控制器对于导弹这类参数快速时变,通道间耦合严重,有不确定因素的系统能够实现解耦控制,并具有动态响应快,超调小的特性。

液压活套多变量系统的建模及积分变结构控制

为了实现热连轧中活套高度与张力系统的解耦控制,需对具有非线性、强耦合、不确定、多约束特性的活套系统建立工程上适用的数学模型.通过对活套系统动态耦合过程的分析,在工作点附件,结合伺服阀和液压缸的模型,建立起液压活套系统的动态数学模型.采用积分滑模变结构多变量解耦控制策略以减弱系统的耦合影响,提高控制效果.仿真结果验证了本算法的有效性,表明解耦后的活套控制系统可获得更好的控制效果.