2DOF discrete dead-time compensators for stable and integrative processes with dead-time

This paper presents an analysis of 2DOF discrete dead-time compensators for stable and integrative processes. The proposed structure can be tuned taking into account the performance and robustness of the closed-loop. Also a novel procedure to choose the sampling period is presented considering the robustness and the disturbance rejection response of the closed-loop system. In order to illustrate the results, some simulation examples and experimental results are shown.     

A double two-degree-of-freedom control scheme for improved control of unstable delay processes

A double two-degree-of-freedom control scheme is proposed for enhanced control of unstable delay processes. The scheme is motivated by the modified Smith predictor control in [IEE Proc. Control Theory Appl. 16(5) (1999) 359] and devised to improve in the following ways: (i) one more freedom of control is introduced in our scheme to enable manipulation of disturbance transient response, and is tuned based on minimization of the integral squared error criterion; (ii) four controllers in the scheme are well placed to separately tune the denominators and numerators of closed-loop transfer functions from the set-point and disturbance. This allows easy design of each controller and good control performance for both set-point and disturbance responses. Especially, improvement of disturbance response is extremely great, compared with [IEE Proc. Control Theory Appl. 16(5) (1999) 359; Automatica 36 (2000) 1651]. Internal stability of the proposed structure is analyzed, which has not been reported in the literature on modified Smith predictor control before. Examples are provided for illustration.     

Design of a sliding mode control system for chemical processes

This paper considers the non-linear regulation control of chemical processes. A novel and systematic sliding mode control system design methodology is proposed, which integrates an identified second-order plus dead-time (SOPDT) model, an optimal sliding surface and a delay-ahead predictor. The convergence property of the closed-loop system is guaranteed theoretically by means of satisfying a sliding condition and the control system performance is examined with some typical chemical processes. Besides, with the concept of delay equivalent, the proposed sliding mode control scheme can be utilized directly to the regulation control of a non-minimum phase process. As a special case the proposed scheme is further extended to the control of chemical processes whose dynamics are simply described by a first-order plus dead-time (FOPDT) model. In addition, the decentralized sliding mode control scheme for multivariable processes is also explored in this paper. Extensive simulation results reveal that the proposed sliding mode control system design methodology is applicable and promising for the non-linear regulation of time-delay chemical processes.     

Multi-sensor information fusion white noise filter weighted by scalars based on Kalman predictor

A unified multi-sensor optimal information fusion criterion weighted by scalars is presented in the linear minimum variance sense. The criterion considers the correlation among local estimation errors, only requires the computation of scalar weights, and avoids the computation of matrix weights so that the computational burden can obviously be reduced. Based on this fusion criterion and Kalman predictor, an optimal information fusion filter for the input white noise, which can be applied to seismic data processing in oil exploration, is given for discrete time-varying linear stochastic control systems measured by multiple sensors with correlated noises. It has a two-layer fusion structure. The first fusion layer has a netted parallel structure to determine the first-step prediction error cross-covariance for the state and the filtering error cross-covariance for the input white noise between any two sensors at each time step. The second fusion layer is the fusion center to determine the optimal scalar weights and obtain the optimal fusion filter for the input white noise. Two simulation examples for Bernoulli-Gaussian white noise filter show the effectiveness.     

一类非自衡加纯滞后系统的双预测P I 控制

提出了一类基于非自衡加大纯滞后过程的双预测PI控制器的结构形式，这种控制器结构筒单，可调参数少，参数的调节方便、直观，仿真结果表明：在干扰和模型失配的情况下，此类控制器仍具有良好的控制性能和鲁棒稳定性，是一种值得在实际工程中推广应用的新型控制器。     

三重马氏平稳过程的预测问题

假设 {X(t) ,t∈R1}是由广义Wiener积分所定义的随机过程 .若这个随机过程被有界Borel可测函数 f(·)变换 ,则得到新的随机过程 f(X(t) ) ,记为Y(t) ,即Y(t) =f(X(t) ) .本文中对于较简单的Borel函数f(·) ,讨论随机过程Y(t) =f(X(t) )的最佳非线性预测量及相应的均方误差等问题     

Evaluation and Choice of Various Branch Predictors for Low-Power Embedded Processor

Power is an important design constraint in embedded computing systems.To meet the power constraint,microarchitecture and hardware designed to achieve high performance need to be revisited,from both performance and power angles.This paper studies one of them:branch predictor.As well known,branch prediction is critical to exploit instruction level parallelism effectively,but may incur additional power consumption due to the hardware resource dedicated for branch prediction and the extra power consumed on mispredicted branches.This paper explores the design space of branch prediction mechanisms and tries to find the most beneficial one to realiz elow-power embedded processor.The sample processor studied is Godson-like processor,which is adual-issue,out-of-order processor with deep pipeline,supporting MIPS instruction set.     

Smith预测器在啤酒发酵系统中的应用

针对啤酒发酵过程大滞后的特点,设计了基于Smith算法的控制器,仿真和试验结果表明,该系统性能稳定,抗干扰能力强.     

基于延时补偿的电网谐波电流信号跟踪控制方法研究

针对电力系统中谐波污染严重等问题,以注入式混合的有源电力滤波器IHAPF作为研究对象,提出了基于延时补偿的谐波电流信号跟踪控制方法。该方法主要由π补偿Smith预估器与神经网络PI控制组成,π补偿Smith预估器使系统延时过程中从控制的闭环内部转换到外部,从而减小了控制延时对系统的影响;通过PSO-BP算法对PI控制器参数进行优化处理,最后对所提方法进行了仿真验证。仿真结果表明,与传统方法相比,本研究所提方法具有更好动态响应特性和更高的稳态补偿精度。     

基于预估器的一类多智能体系统神经动态面输出一致控制

本文针对一类含未知扰动与非对称输入饱和的非线性多智能体系统,提出基于预估器的神经动态面输出一致控制策略.在设计预估器的基础上构造预估误差,驱动神经网络更新权值估计系统未知动态,并将预估器与神经网络应用于非线性扰动观测器来补偿广义扰动.本文所提出的控制策略采用神经网络权值范数学习方法,减少学习参数数目.对于非对称的输入饱和,设计辅助系统,其生成的辅助变量与反步法相结合补偿输入限制.结合图论知识和Lyapunov函数等技术,证明多智能体系统的输出一致跟踪误差以及闭环系统中的所有信号最终有界.最后通过一组四旋翼飞行器和数值仿真验证提出控制策略的有效性.