Adaptive harmonic steady‐state control for rejection of sinusoidal disturbances acting on a completely unknown system

This paper presents an adaptive harmonic steady‐state (AHSS) controller that addresses the problem of rejecting sinusoids with known frequencies that act on a completely unknown asymptotically stable linear time‐invariant system. We analyze the stability and closed‐loop performance of AHSS for multi‐input multi‐output systems that are square (ie, the number of controls equals the number of performance measurements). In this case, we show that AHSS asymptotically rejects disturbances, that is, the performance measurement tends to 0. We also present a numerical study of the steady‐state and transient performance of AHSS for square and nonsquare systems.     

Modified reduced order observer based linear active disturbance rejection control for TITO systems

This paper proposes an observer based control approach for two input and two output (TITO) plant affected by the lumped disturbance which includes the undesirable effect of cross couplings, parametric uncertainties, and external disturbances. A modified reduced order extended state observer (ESO) based active disturbance rejection control (ADRC) is designed to estimate the lumped disturbance actively as an extended state and compensate its effect by adding it to the control. The decoupled mechanism has been used to determine the controller parameters, while the proposed control technique is applied to the TITO coupled plant without using decoupler to show its efficacy. Simulation results show that the proposed design is efficiently able to nullify the interactions within the loops in the multivariable process with better transient performance as compared to the existing proportional-integral-derivative (PID) control methods. An experimental application of two tanks multivariable level control system is investigated to present the validity of proposed scheme.     

基于线性自抗扰控制技术的永磁同步电机控制策略研究

永磁同步电机(PMSM)具有体积小、高速度、高精度等优势,广泛应用于现代工程实际当中。在多数情况下其控制策略采用经典的PID控制,但较多的实际复杂环境当中,传统的PID所暴露的固有缺陷已经无法满足PMSM的控制高效性。采用先进的线性自抗扰控制策略,其具有不依赖具体对象模型,控制器自身可以估计补偿作用于被控对象的所有扰动的优势,实验仿真结果表明,该方案有效抑制了扰动,进而提高了系统的控制性能。     

Active disturbance rejection generalized predictive control for a high purity distillation column process with time delay

High purity distillation processes have been widely used in the chemical industry. These processes have unique characteristics including higher order, nonlinearity, strong coupling, and time delay. In order to overcome these control issues, an active disturbance rejection generalized predictive control strategy is designed for the distillation column with time delay. The strategy combines the structures of both active disturbance rejection control and generalized predictive control. A delayed designed extended state observer can estimate the model uncertainty and external disturbance, and a non‐incremental generalized predictive control is proposed to deal with the integrators with time delay. Therefore, it rejects disturbances well and has the capability of overcoming time delay. The computation load is also less than the generalized predictive control. In the simulation experiments, the proposed strategy is compared with robust control and model predictive control. The results illustrate that the proposed control strategy has improved robustness performance in dealing with model uncertainties, various disturbances, and time delay.     

Advanced daytime polysomnographic preprocessing: A versatile approach for stream-wise estimation

The enhancement of monitoring biosignals plays a crucial role to thrive successfully computer-assisted diagnosis, ergo the deployment of outstanding approaches is an ongoing field of research demand. In the present article, a computational prototype for preprocessing short daytime polysomnographic (sdPSG) recordings based on advanced estimation techniques is introduced. The postulated model is capable of performing data segmentation, baseline correction, whitening, embedding artefacts removal and noise cancellation upon multivariate sdPSG data sets. The methodological framework includes Karhunen–Loève Transformation (KLT), Blind Source Separation with Second Order Statistics (BSS-SOS) and Wavelet Packet Transform (WPT) to attain low-order, time-to-diagnosis efficiency and modular autonomy. The data collected from 10 voluntary subjects were preprocessed by the model, in order to evaluate the withdrawal of noisy and artefactual activity from electroencephalographic (EEG) and electrooculographic (EOG) channels. The performance metrics are distinguished in qualitative (visual inspection) and quantitative manner, such as: Signal-to-Interference Ratio (SIR), Root Mean Square Error (RMSE) and Signal-to-Noise Ratio (SNR). The computational model demonstrated a complete artefact rejection in 80% of the preprocessed epochs, 4 to 8 dB for residual error and 12 to 30 dB in signal-to-noise gain after denoising trial. In comparison to previous approaches, N-way ANOVA tests were conducted to attest the prowess of the system in the improvement of electrophysiological signals to forthcoming processing and classification stages.     

Reduced-order model based active disturbance rejection control of hydraulic servo system with singular value perturbation theory

Hydraulic servomechanism is the typical mechanical/hydraulic double-dynamics coupling system with the high stiffness control and mismatched uncertainties input problems, which hinder direct applications of many advanced control approaches in the hydraulic servo fields. In this paper, by introducing the singular value perturbation theory, the original double-dynamics coupling model of the hydraulic servomechanism was reduced to a integral chain system. So that, the popular ADRC (active disturbance rejection control) technology could be directly applied to the reduced system. In addition, the high stiffness control and mismatched uncertainties input problems are avoided. The validity of the simplified model is analyzed and proven theoretically. The standard linear ADRC algorithm is then developed based on the obtained reduced-order model. Extensive comparative co-simulations and experiments are carried out to illustrate the effectiveness of the proposed method.     

Adaptive internal model guidance law for weaving maneuvering target

For the terminal phase guidance problem of the missile intercepting weaving maneuvering target, an adaptive internal model guidance laws in the three-dimensional (3-D) engagement space is proposed in this paper. The guidance law adopts the disturbance rejection theory by treating the target weaving maneuvering accelerations as external disturbance, which comprises of nominal part and adaptive part. The nominal part based on feedback linearization method ensures the whole guidance system stable and the adaptive part based on internal model principle is used to recover the disturbance signals on-line to reject the target maneuver asymptotically. The algorithm guarantees the whole guidance system with satisfying performance both in transient and steady state on the effect of target maneuver on guidance system. The stability analyses and theory proof are provided in this paper. At last, numerical simulations are carried out to illustrate the effectiveness of the proposed guidance law.     

Impact and Assessment of Measurement Systems that Meet the 4:1 Rule

This article considers the impact of a measurement system that meets the 4:1 rule. Probabilities of accepting a bad part and rejecting a good part are evaluated. A simulation study calculates the increased estimates of the population standard deviation when the measurement error is ignored, where both non‐trending and trending populations are considered. Also, the impact of sample size is evaluated on estimates and upper confidence bounds of the measurement system standard deviation that are used to assess the 4:1 rule capability; both measurement systems from a single and multiple sources of variation are explored. Copyright © 2014 John Wiley & Sons, Ltd.     

日盲雪崩探测器滤波膜系的优化设计及器件性能的影响

利用传输矩阵法设计了空气与基本膜系之间具 有3个周期减反膜结构的日盲紫外探测器滤波膜系,并利用半导体 器件仿真软件Atlas分析集成了滤波膜系的GaN/AlGaN异质结雪崩光电探测器(APDs)的光 电性能。研究结果表明,相对 无减反射膜的滤波膜系,本文设计的膜系明显提高了光在日盲区的透过率及截止区的反射率 ,使GaN/AlGaN APDs有更 加平滑的光谱响应曲线、更大的响应度、更陡峭的响应截止边频及更好的滤波性能;同时, GaN/AlGaN APDs比传统AlGaN APDs 更有利于光生空穴的注入,使GaN/AlGaN APDs的最大光谱响应度及紫外/可见抑制比较传统的 APDs提高超过300%。     

高精度稳定平台伺服系统的自抗扰控制

提出了一种应用于高精度稳定平台伺服系统的设计方法。为满足稳定平台快速隔离扰动、稳定视轴的要求,将自抗扰控制应用于平台系统的速度环,和常规PID控制的电流环一起构成ADRC-PID控制。Simulink仿真结果表明,与传统PID控制相比,采用自抗扰控制后系统响应速度快,隔离度有较大的提高。ADRC-PID控制可满足高精度光电稳定平台的性能要求,系统具有响应速度快,隔离度好,鲁棒性强,稳定性高等特点。