Composite Adaptive Control of Belt Polishing Force for Aero-engine Blade

The existing methods for blade polishing mainly focus on robot polishing and manual grinding.Due to the difficulty in high-precision control of the polishing force,the blade surface precision is very low in robot polishing,in particular,quality of the inlet and exhaust edges can not satisfy the processing requirements.Manual grinding has low efficiency,high labor intensity and unstable processing quality,moreover,the polished surface is vulnerable to burn,and the surface precision and integrity are difficult to ensure.In order to further improve the profile accuracy and surface quality,a pneumatic flexible polishing force-exerting mechanism is designed and a dual-mode switching composite adaptive control(DSCAC) strategy is proposed,which combines Bang-Bang control and model reference adaptive control based on fuzzy neural network(MRACFNN) together.By the mode decision-making mechanism,Bang-Bang control is used to track the control command signal quickly when the actual polishing force is far away from the target value,and MRACFNN is utilized in smaller error ranges to improve the system robustness and control precision.Based on the mathematical model of the force-exerting mechanism,simulation analysis is implemented on DSCAC.Simulation results show that the output polishing force can better track the given signal.Finally,the blade polishing experiments are carried out on the designed polishing equipment.Experimental results show that DSCAC can effectively mitigate the influence of gas compressibility,valve dead-time effect,valve nonlinear flow,cylinder friction,measurement noise and other interference on the control precision of polishing force,which has high control precision,strong robustness,strong anti-interference ability and other advantages compared with MRACFNN.The proposed research achieves high-precision control of the polishing force,effectively improves the blade machining precision and surface consistency,and significantly reduces the surface roughness.

Interpolation mechanism of fuzzy control

The fuzzy control algorithms used commonly at present are all regarded as some interpolation functions, which is in essence equivalent to discrete response functions to be fitted. This means that fuzzy control method is similar to finite element method in mathematical physics, which is a kind of direct manner or numerical method in control systems.

Fuzzy控制的本质与一类高精度Fuzzy控制器的设计

本文揭示，Fuzzy控制器在本质上就是某种插值器．首先阐明Fuzzy控制的插值机理，然后讨论常用的双输入单输出分片插值器，最后介绍基于论域收缩的一类高精度Fuzzy控制器的设计思想．

基于级联式模糊控制的电氢耦合直流微网能量管理策略研究

针对电氢混合储能系统在平抑直流微网中功率波动时面临的功率分配问题,提出了一种基于级联式模糊控制的电氢耦合直流微网能量管理策略。该策略中一次模糊控制器依据储氢罐储氢状态(stateofhydrogenstorage,SOH)与锂电池荷电状态(state of charge, SOC)求解出一次功率分配因子,对直流微网净功率进行一次分配;二次模糊控制器结合一次功率分配参考值与SOH对一次功率分配因子作出校正。此外,为使氢储能系统中具有非线性工作特性的电流控制型装置(电解槽、燃料电池)能够对能量管理系统作出高效响应,采用插值法将功率分配参考值转换为电流参考值。通过Matlab/Simulink仿真结果证明,所提能量管理策略有效缩小了氢储能系统在非合理区间的功率波动范围并提高了氢储能系统中装置的响应精度与速度。

Adaptive fuzzy controllers based on variable universe

Adaptive fuzzy controllers by means of variable universe are proposed based on interpolation forms of fuzzy control. First, monotonicity of control rules is defined, and it is proved that the monotonicity of interpolation functions of fuzzy control is equivalent to the monotonicity of control rules. This means that there is not any contradiction among the control rules under the condition for the control rules being monotonic. Then structure of the contraction-expansion factor is discussed. At last, three models of adaptive fuzzy control based on variable universe are given which are adaptive fuzzy control model with potential heredity, adaptive fuzzy control model with obvious heredity and adaptive fuzzy control model with successively obvious heredity.

Relationship between fuzzy controllers and PID controllers

The internal relations between fuzzy controllers and PID controllers are revealed. First, it is pointed out that a fuzzy controller with one input and one output is just a piecewise P controller. Then it is proved that a fuzzy controller with two inputs and one output is just a piecewise PD (or I) controller with interaction between P and D (or PI). At last, the conclusion that a fuzzy controller with three inputs and one output is just a piecewise PID controller with interaction among P, I and D is given. Moreover, a kind of difference scheme of fuzzy controllers is designed.

Modelling on fuzzy control systems

A kind of modelling method for fuzzy control systems is first proposed here, which is called modelling method based on fuzzy inference (MMFI). It should be regarded as the third modelling method that is different from two well-known modelling methods, that is, the first modelling method, mechanism modelling method (MMM), and the second modelling method, system identification modelling method (SIMM). This method can, based on the interpolation mechanism on fuzzy logic system, transfer a group of fuzzy inference rules describing a practice system into a kind of nonlinear differential equation with variable coefficients, called HX equations, so that the mathematical model of the system can be obtained. This means that we solve the difficult problem of how to get a model represented as differential equations on a complicated or fuzzy control system.

大型风电机组三维模糊控制器设计与仿真

为提高风电机组的响应速度,获得最大功率,现有大型风电机组普遍采用变速变桨距控制机构。但由于风速的随机性、风电机组参数的时变性和系统的非线性,造成风电机组输出功率的不稳定。根据传统PID控制系统的局限性和风电机组的特性,提出了三维模糊控制器,但多维模糊控制复杂的规则会严重影响系统的实时性。为了达到多维控制系统的控制品质,控制规则以表达式的形式给出,同时结合三元函数的Lagrange插值法,使系统输出的离散变量转变成连续精确的控制变量以提高控制精度。运用SIMULINK的仿真结果表明,三维模糊控制器显著地提高了系统的控制品质,其鲁棒性也明显优于PID控制系统。

提高模糊控制器控制精度的实用方法

分析了常规模糊控制器的控制精度低的原因,提出了一种提高模糊控制器控制精度的实用方法。即当系统误差为零时,通过插值计算得到控制输出的模糊控制器的零点插值算法。仿真结果表明,这种改进的模糊控制器具有消除系统稳态误差的作用,提高了模糊控制器的控制精度,其动态性能好,可以提高采样的速度,减少采样周期,易于实现,有一定的实用价值。

模糊相似度推理算法及其构造的模糊系统逼近性能的分析

本文首先将相似度理论进一步推广,给出了模糊相似度的公理化定义;然后给出了基于模糊相似度的推理算法,证明了该算法是规则再现的;进一步地,对基于模糊相似度推理算法构造的模糊系统的逼近性能进行了理论分析,给出了该系统具有插值性的充要条件,并给出了满足该条件的两个模糊相似度。最后,证明了当满足一定条件时,该系统具有二阶逼近精度。

单入单出模糊控制器控制函数与插值式的偏差分析

本文进一步分析了单入单出模糊控制器的插值机理,借助符号计算推导了模糊蕴涵算子分别选择取小算子和乘积算子时,单入单出模糊控制器控制函数的解析式;得到了控制函数与插值函数间的偏差表达式.最后本文给出了偏差的一个上界估计以及模糊控制器实际使用时确定规则数的公式.

基于模糊控制的数字式自动准同期装置

介绍了一种以 DSP为微处理器的数字式自动准同期装置,采用模糊控制技术对发电机电压和频率进行调节,实现了快速、平稳地达到并网条件;应用线性插值算法预测相角差来自动捕捉合闸时机;除了传统的同期功能外,还具有事件记录、录波等功能。经测试,该装置能实现高精度、快速、可靠、平稳的并网操作。

自适应模糊控制器的实现

设计了一个二维自适应模糊控制器,将误差的量化因子设计成自适应调整因子,并应用线性插值法查控制表。对控制系统进行仿真,将控制结果与一般的模糊控制器的控制效果进行比较,说明此方法对改善控制性能是有利的。

典型模糊PID控制器的插值算法及参数优化

推导出了输入采用正规模糊集、三角形、全交迭的隶属度函数;推理输出采用PID形式的典型模糊PID控制器的插值解析表达式,揭示了其本质特征,为实际应用提供了一种快速精确的控制算法。基于该插值解析表达式,研究了利用遗传算法对这一类模糊控制器进行参数优化的方法。最后通过仿真实例验证了本文方法的有效性。

基于牛顿插值算法的模糊控制器

提出一种基于牛顿在线插值算法的模糊控制器,介绍该控制器的设计方法。该方法既简化了合成推理运算,又能满足模糊控制规则的完整性要求,从本质上消除由于量化误差和调节死区给模糊控制系统带来的稳态误差与颤振现象。通过仿真证明系统的性能得到明显改善。

一种在线插值模糊控制方法及应用

在修正因子模糊控制方法中引入了在线插值算法,并将其应用于水箱液位控制系统中。实验结果表明:此方法能从本质上消除系统的稳态误差,明显地改善了模糊控制系统的稳态性能。

基于不同蕴涵算子的三I算法构造的模糊控制器及其响应能力

以RM,RZ,R03个蕴涵算子为基础,给出了其相应三I算法的表达式,并研究了这3个蕴涵算子基于三I算法构成的单入单出模糊控制器,分析了它们的响应能力.结果表明,当Ri(i=1,2,3)按顺序取R0,RM,RZ时基于三I算法构成的单入单出模糊控制器具有函数的泛逼近性;当Ri(i=1,2,3)按顺序分别取RM,RZ,RZ或R0,RZ,RM时基于三I算法构成的单入单出模糊控制器近似为一元拟合函数;其余情况基于三I算法构成的模糊控制器具有阶跃响应能力.

一种高精度模糊控制系统的设计方法

采用知形域上分片双一次插值方法对模糊控制表进行插值，使在线控制时的模糊控制器输入、输出值均取连续可变量，克服了普通模糊控制系统因控制器输入、输出变量量化所造成的控制精度低与可能出现的稳态颤振等缺点。仿真结果表明该方法具有优良的控制品质。

带自调整函数的模糊控制器在直流电机调速系统中的应用

提出一种带自调整函数的模糊控制器与二元函数的Lagrange插值算法相结合的控制算法,并将该算法应用于直流电机调速系统。自调整函数为指数函数,根据控制对象的具体情况和要求的不同,自调整函数中各参数可通过键盘进行调试。插值算法采用分片双二次Lagrange插值算法,调速实验结果表明了该控制算法的合理性和有效性。

基于样条插值的模糊控制算法

利用三次样条插值函数,直接由控制输入输出数据对建立了控制输入与控制输出之间的映射关系,得到了一元三次样条插值控制算法和二元双三次样条插值控制算法,并将二者分别用于单输入单输出系统和双输入单输出系统的仿真控制。仿真结果表明,上述方法是可行的,并且基于三次样条函数的模糊插值控制,具有响应快,无超调,稳态误差极小等很好的控制效果。其设计简单,不需要过多规则,对稀疏规则库条件下的控制器设计尤为适用。