基于积分时滞系统史密斯预估器的研究

在积分时滞系统(IPDT)中,传统的史密斯预估器不能很好的消除稳态误差,而且在模型失配时易产生欠补偿问题.为此,文中提出了改进型的史密斯预估器,首先利用反馈控制器,将实际过程与模型过程的误差反馈到控制信号端.其次,在控制对象端加上串联控制器和反馈补偿控制器,分别采用不同的方法进行设计,以消除扰动对系统的影响. MATLAB仿真结果显示,系统具有较好的输出响应,能够有效消除扰动误差.     

线性自抗扰控制的抗饱和补偿措施

控制输入约束是实际工业过程中普遍存在的现象,然而控制器设计中通常都假设执行机构动态是线性的,因此当执行机构存在约束时,执行机构输出信号与控制器输出信号不一致,使系统的动态性能降低,甚至导致系统不稳定.本文针对线性自抗扰控制(linearactive disturbance rejection control,LADRC)执行机构的约束问题,提出两种抗饱和补偿方案,利用LADRC扩张状态观测器估计控制器状态或者控制器输出与执行器输出的误差,从而使LADRC能快速消除饱和.将这两种方法用到含执行机构饱和的一阶惯性加迟延被控对象进行仿真研究,结果表明两种补偿措施下线性自抗扰控制器能得到较好的控制性能.随后本文将LADRC抗饱和思想推广到负荷频率控制系统(load frequency control,LFC)中,仿真表明基于误差补偿的抗饱和方案对于LFC系统更为有效.     

基子CYGNAL单片机和FPGA的舞台吊杆控制器的设计

介绍了舞台吊杆控制系统的体系结构,并对组成该系统的舞台吊杆控制器进行了研究,论述了其工作原理,提出了用CYGNAL单片机和FPGA设计该控制器的方法.基于SOC的设计思想,完成了该控制器的硬件和软件两方面的设计,提出了控制系统中的位移测量方法,并对电机惯性引起的误差提出了补偿方法;同时针对该系统采取了相应的抗干扰措施,提高了系统的抗干扰能力.实际应用证明,此控制器抗干扰能力强,吊杆位置控制精确,且安全可靠.     

溶解氧浓度的直接自适应动态神经网络控制方法

针对污水处理过程溶解氧浓度的控制问题,提出一种直接自适应动态神经网络控制方法(direct adaptive dynamic neural network control,DADNNC).构建的控制系统主要包括神经网络控制器和补偿控制器.神经网络控制器由自组织模糊神经网络实现系统状态与控制量之间的映射;提出一种基于规则无用率的结构修剪算法,并给出结构调整后网络收敛的理论证明.同时,为保证系统稳定,设计补偿控制器减小网络逼近误差,参数调整由Layapunov理论给出.国际基准仿真平台上的实验表明,与固定结构神经网络控制器、PID和模型预测控制等已有控制方法相比,DADNNC方法具有更高的控制精度和更强的适应能力.     

模糊免疫PID的Smith预估主汽温控制系统

针对火电厂机组主汽温被控对象的大迟延和模型参数不确定性,结合传统Smith预估控制方法和模糊免疫PID控制方法,设计了基于Smith预估的模糊免疫PID控制器.模糊免疫PID控制器可自整定参数,对被控对象参数变化有自适应能力,在纯迟延现象严重的惰性区使用预估器预先估计出过程在基本扰动下的动态特性,使调节器提前动作,从而明显地减少超调量.将设计的控制器应用到主汽温串级控制系统中,并用Matlab对该系统在不同工况下进行仿真,结果表明所设计的控制系统对模型参数变化有较强的适应能力,在稳定性,准确性方面优于常规Smith预估控制系统和串级控制系统.     

基于扰动观测器补偿的机械臂非奇异快速终端滑模控制

针对机械臂系统在实际应用中存在的建模误差及未知扰动问题, 设计了一种基于扰动观测器的改进型非 奇异快速终端滑模控制策略. 通过扰动观测器准确估计系统存在的总扰动, 并设计恰当的非线性增益函数使扰动观 测误差指数收敛, 实现了对控制器的前馈补偿. 考虑到终端滑模存在的奇异性问题, 结合扰动观测器设计了非奇异 快速终端滑模控制器, 在保证跟踪误差有限时间收敛的同时抑制了滑模控制固有的抖振现象. 同时在控制器设计过 程中, 用fal函数代替sig函数有利于削弱滑模控制抖振, 提高系统稳定性及跟踪精度. 最后, 利用MATLAB软件进行 实验仿真, 验证了所设计控制器的有效性.     

机器人的鲁棒预测控制

本文提出基于误差预测的机器人鲁棒控制器。考虑到机器人的动力学建模误差影响其控制性能,本文建立机器人的误差模型,给出预测建模误差对运动轨迹偏差的作用的有效方法,并提出建模误差的鲁棒性补偿。本文分别在关节空间和直角空间针对冗余机器人和非冗余机器人提出鲁棒预测控制器设计,其有效性由仿真例子检验。     

内置RTC作为电能表计时钟的应用

为降低电能表的成本,提高时钟的精确度,设计了一个基于ST微控制器的RTC时钟控制器.该时钟控制器采用内置RTC的原理,通过温度补偿晶体的频偏和校准秒脉冲的输出等方式得到精准的时钟.试验数据表明,通过温度补偿晶体的频偏和秒脉冲输出校准方法相结合,使RTC时钟在(-40℃,85℃)温度范围内的误差小于0.5 s/d.该RTC时钟控制器目前已应用于国网二代三相多功能电能表.     

弹性飞行器的H∞控制器设计与仿真

弹性飞行器动力学模型用很多自由度来描述弹性模态和刚性模态,由此引起的模型不确定性及建模误差,使用常规控制器很难保证系统的鲁棒稳定性.为此,采用H∞混合灵敏度控制方法设计了能控制弹性飞行器姿态运动又能快速抑制结构振动的鲁棒控制器,采用平衡截断法对此高阶控制器进行了降阶,得到6阶和4阶控制器,对于降阶控制器的控制效果进行了仿真研究.仿真结果表明,降阶后的控制器能很好地实现对原全阶控制器的近似,系统增强稳定性.鲁棒性能满足设计的要求,为飞行系统提供了设计依据.     

主轴回转误差补偿控制器

基于主轴回转误差模板补偿控制方法研制成功了以MCS-51 为核心的主轴回转误差补偿控制器。结构简单、性能稳定、成本低廉,具有良好的应用前景。     

Sub-optimal PID controller settings for FOPDT systems with long dead time

We propose a method for setting up PI and PID controllers based on stable FOPDT process model, where dead-time dynamics is manipulated without approximation. The main idea used is a partial compensation of the system dynamics, which makes possible obtaining simple tuning rules. Remaining unknown controller parameters are determined on the basis of the modulus optimum and the minimum ISE criterions. Besides the performance indices, quality of the settings is also evaluated by the stability margin. Although optimal values of the parameters are valid for the reference tracking problem, a compensation of the disturbance lag that preserves the stability margin is proposed for the disturbance rejection problem.     

State analytical predictor for systems with multiple time delays

An approach for the design of a dead-time compensator for processes with time delays is presented. The proposed algorithm deals with multivariable state-space models instead of input-output models and utilizes not only a single delay but also distributed delays in the feedback loop. Both the continuous-time and discrete-time versions of the algorithm are derived. The design strategy of the controller is based on the approach of LQG design. It is incorporated into the dead-time compensation technique of the analytical predictor, which uses the process model directly to predict the effect of input variables on the process outputs. By introducing an integral action into the observation system, the steady-state observation error of the inaccessible load inputs converges to zero. This permits us to perform disturbance prediction and compensation within a single design. Theoretical analysis shows that this control strategy fully removes time delay elements from a system characteristic equation in the ideal situation of a system without model-plant mismatch and/or noise measurements. By the estimation and prediction of the unknown plant-input disturbances, the capability for rejecting input disturbances has also been improved. The control structure developed is shown to have the same closed-loop relationships as the linear quadratic feedback structure for a system without lime delays. The potential benefits of the proposed controller are demonstrated by the control problem of an industrial grinding system studied previously by Niemi et al. (1982) and Ylinen et al. (1987), which is a challenging problem for MPC-type algorithms.     

典型工业过程鲁棒PID控制器的整定

提出一阶迟延过程、积分迟延过程、不稳定迟延过程和二阶迟延过程等典型工业过程的鲁棒PID整定公式.本文从抗干扰性能和鲁棒性能两方面综合考虑,把鲁棒PID控制器的设计问题转化为求解一个带鲁棒性能约束的绝对误差积分指标(IAE)优化问题.鉴于该问题是非凸的,本文采用遗传算法来求解,并通过曲线拟合得到典型工业过程的PID控制器的整定公式.仿真结果表明本文的PID整定公式有效,且控制器具有良好的抗干扰能力和频域鲁棒性.     

On the explicit dead-time compensation for robust model predictive control

Computational simplicity is one of the most important aspects to take into account in robust model predictive control (MPC). In dead-time processes, it is common to use an augmented state-space representation in order to apply robust MPC strategies but, this procedure may affect computational aspects. In this paper, explicit dead-time compensation will be used to avoid augmented representation. This technique will be analyzed in terms of robust stability and constraint satisfaction for discrete-time linear systems. The results of this discussion will be applied to a robust tube-based MPC strategy which is able to guarantee robust stability and constraint satisfaction of a dead-time system by considering a prediction model without dead-time. Moreover, taking advantage of the proposed scheme, the robust MPC will be particularized for first-order plus dead-time models which simplifies significantly controller synthesis. The proposed dead-time compensation method will be applied to different robust MPC strategies in two case studies: (i) a simulated quadruple-tank system, and (ii) an experimental scaled laboratory heater process.     

具有死区补偿的自抗扰控制下PMSM转矩脉动抑制方法

空间矢量脉宽调制死区效应对永磁同步电机(PMSM) 的调速控制系统及转矩脉动有一定影响, 为了削弱其不利作用, 在永磁同步电机矢量控制基础上, 提出一种新型的具有死区补偿的自抗扰PMSM控制方案, 针对传统自抗扰控制策略下电机转矩脉动较大的缺陷, 在原有的自抗扰控制策略中加入死区补偿. 仿真及实验结果表明, 具有死区补偿的自抗扰PMSM驱动系统, 谐波含量明显减少, 速度驱动系统更加平稳, 有效抑制了转矩脉动.

     

一种基于插值预测的新型电流滤波方法

在常规的死区补偿方法中，大多是建立在预先知道输出电流极性的基础上。但是由于谐波的干扰，输出电流在零点附近会出现振荡反复的现象，从而让常规的死区补偿方法出现错误补偿现象。所以，为了实现死区效应的正确补偿，滤除输出电流的零点振荡与毛刺是必要的。鉴于此点，本文提出了一种新型的电流滤波方法，很好的消除了输出电流的毛刺与零点振荡。     

模糊控制器优化方法及其在传感器补偿中的应用

为了减小压力传感器温度漂移造成的测量误差,使用0阶T—S模糊控制器对压力传感器温度附加误差进行校正,校正后的误差为±0.3%,且零位温度系数和灵敏度温度系数都降低1个数量级以上。使用模拟退火算法对模糊规则进行寻优,提高了校正精度,并保持了0阶T—S模糊控制器运算简单和速度快的特点,使之能快速地完成传感器的温度补偿。     

A unified step response procedure for autotuning of PI controller and Smith predictor for stable processes

The step response autotuning of PI controller and Smith dead-time compensator (DTC), for stable processes, is studied in detail. A simple and effective procedure proposed is based on the first-order plus dead-time model, obtained from the step response by measuring the time to go to ten and sixty three percent of the steady-state value of the process output. The tuning formulae derived contain an adjustable parameter, with a clear meaning with respect to the performance/robustness, enabling the user to specify its value within a well defined range, in accordance with the expected range of process parameter variations and the controller used (PI or DTC). Comparison with recently proposed methods and experimental results presented confirm that high and consistent closed-loop system performance/robustness are obtained for a wide range of dynamic characteristics common to industrial processes.     

Robust compensation of time delayed plant by continuous‐time high frequency periodic controller with negligible output ripples

The present work addresses the problem of ensuring robust stability to time delayed plants, compensated with continuous‐time high frequency periodic controller. An efficient design methodology is proposed to synthesize the periodic controller for robust compensation of time delayed linear time‐invariant plants. The periodic controller, by virtue of its loop zero‐placement capability, is shown to achieve superior gain as well as phase/delay margin compensation, especially for non‐minimum phase plants having right half plane poles and zeros in close vicinity to each other. The periodic controller is considered in the observable canonical form which results in realizable bounded control input as well as ensuring insignificant periodic oscillations in the plant output. As a consequence, this paper, furthermore, establishes the fact that the periodic controller designed and synthesized with the proposed methodology can be implemented in real‐time with an assurance of model matching and robust zero‐error tracking. Simulation and experimental results are illustrated to establish the veracity of the claims. The closed‐loop system comprising of time‐delayed linear time‐invariant plant with the periodic controller is analyzed employing the averaging principle and presented here explicitly in a meticulous approach. Copyright © 2015 John Wiley & Sons, Ltd.