High order single step time delay compensation algorithm for structural active control

The optimal instantaneous high order single step algorithm for active control is first discussed and then, the n+1 time step controlling force vector of the instantaneous optimal algorithm is derived from way of n time state vector. An estimating algorithm, is developed from this to solve the problem of active control with time delay compensation. The estimating algorithm based on this high order single step β method (HSM) foundation, is proven by simulation and experiment analysis, to be a valid solution to problem of active control with time delay compensation.

An Analysis of the Static and Dynamic Behavior of the Hydraulic Compensation System of a Multichannel Valve

Electro-hydraulic proportional valve is the core control valve in many hydraulic systems used in agricultural and engineering machinery.To address the problem related to the large throttling losses and poor stability typically associated with these valves,here,the beneficial effects of a triangular groove structure on the related hydraulic response are studied.A mathematical model of the pressure compensation system based on the power-bond graph method is introduced,and the AMESim software is used to simulate its response.The results show that the triangular groove structure increases the jet angle and effectively compensates for the hydrodynamic force.The steady-state differential pressure at the valve port of the new pressure compensation structure was 0.65 MPa.Furthermore,experimental results show that the pressure difference at the main valve port is 0.73 MPa,and that the response time is less than 0.2 s.It is concluded that the new compensation structure has good pressure compensation response characteristics.

Time-delay Positive Feedback Control for Nonlinear Time-delay Systems with Neural Network Compensation

新适应时间延期积极反馈控制器(ATPFC ) 为非线性的时间延期系统的一个班被介绍。建议控制计划由神经基于网络的鉴定和时间延期组成积极反馈控制器。与一个特殊动态鉴定模型一起合并的二个高顺序的神经网络(HONN ) 被采用识别非线性的系统。基于识别模型，本地 linearization 赔偿被用来处理系统的未知非线性。线性化的系统的一个 time-delay-free 逆模型和一个需要的引用模型被利用组成反馈控制器，它能导致系统输出追踪一个引用模型的轨道。为鉴定和靠近环的控制系统的追踪的错误的严密稳定性分析借助于 Lyapunov 稳定性标准被提供。模拟结果被包括表明建议计划的有效性。

Comparison of delay compensation methods for real-time hybrid simulation using frequency-domain evaluation index

The delay compensation method plays an essential role in maintaining the stability and achieving accurate real-time hybrid simulation results. The effectiveness of various compensation methods in different test scenarios, however, needs to be quantitatively evaluated. In this study, four compensation methods （i.e., the polynomial extrapolation, the linear acceleration extrapolation, the inverse compensation and the adaptive inverse compensation） are selected and compared experimentally using a frequency evaluation index （FEI） method. The effectiveness of the FEI method is first verified through comparison with the discrete transfer fimction approach for compensation methods assuming constant delay. Incomparable advantage is further demonstrated for the FEI method when applied to adaptive compensation methods, where the discrete transfer function approach is difficult to implement. Both numerical simulation and laboratory tests with predefined displacements are conducted using sinusoidal signals and random signals as inputs. Findings from numerical simulation and experimental results demonstrate that the FEI method is an efficient and effective approach to compare the performance of different compensation methods, especially for those requiring adaptation of compensation parameters.

Code synchronization based on lumped time-delay compensation scheme with a linearly chirped fiber Bragg grating in all-optical analog-to-digital conversion

We propose a novel lumped time-delay compensation scheme for all-optical analog-to-digital conversion based on soliton self-frequency shift and optical interconnection techniques. A linearly chirped fiber Bragg grating is optimally designed and used to compensate for the entire time-delays of the quantized pulses precisely. Simulation results show that the compensated coding pulses are well synchronized with a time difference less than 3.3 ps, which can support a maximum sampling rate of 151.52 GSa/s. The proposed scheme can efficiently reduce the structure complexity and cost of all-optical analog-to-digital conversion compared to the previous schemes with multiple optical time-delay lines.

A Novel Clock Feedthrough Frequency Compensation for Fast-Settling of Folded-Cascode OTA

Based on the minimum settling time （MST） theory and step-response analysis of the second order system in active switched capacitor （SC） networks, a novel clock feedthrough frequency compensation （CFFC） method for a folded-cascode OTA is proposed. The damping factor r/is adjusted by using MOS capacitors to introduce clock feedthrough so that the OTA can obtain the MST state and thus achieve fast settling. Research results indicate that the settling time of the compensated OTA is reduced by 22.7% ;as the capacitor load varies from 0.5 to 2.5pF,the improved settling time increases approximately linearly from 3.62 to 4.46ns： for VGA application, fast settling can also be achieved by modifying the MOS capacitor value accordingly when the closed loop gain of the compensated OTA varies.

A Delay-Dependent Anti-Windup Compensator for Wide-Area Power Systems With Time-Varying Delays and Actuator Saturation

In this paper, a delay-dependent anti-windup compensator is designed for wide-area power systems to enhance the damping of inter-area low-frequency oscillations in the presence of time-varying delays and actuator saturation using an indirect approach. In this approach, first, a conventional wide-area damping controller is designed by using output feedback with regional pole placement approach without considering time-varying delays and actuator saturation. Then to mitigate the effect of both time-varying delays and actuator saturation, an add-on delay-dependent anti-windup compensator is designed. Based on generalized sector conditions, less conservative delay-dependent sufficient conditions are derived in the form of a linear matrix inequality(LMI) to guarantee the asymptotic stability of the closedloop system in the presence of time-varying delays and actuator saturation by using Lyapunov-Krasovskii functional and Jensen integral inequality. Based on sufficient conditions, the LMI-based optimization problem is formulated and solved to obtain the compensator gain which maximizes the estimation of the region of attraction and minimizes the upper bound of-gain. Nonlinear simulations are performed first using MATLAB/Simulink on a two-area four-machine power system to evaluate the performance of the proposed controller for two operating conditions, e.g.,3-phase to ground fault and generator 1 terminal voltage variation. Then the proposed controller is implemented in real-time on an OPAL-RT digital simulator. From the results obtained it is verified that the proposed controller provides sufficient damping to the inter-area oscillations in the presence of time-varying delays and actuator saturation and maximizes the estimation of the region of attraction.

Periodic Error Compensation for Quartz MEMS Gyroscope Drift of INS

In order to improve the navigation accuracy of an inertial navigation system （INS）, composed of quartz gyroscopes, the existing real-time compensation methods for periodic errors in quartz gyroscope drift and the periodic error term relationship between sampled original data and smoothed data are reviewed. On the base of the results, a new compensation method called using former period characteristics to compensate latter smoothness data （UFCL for short） method is proposed considering the INS working characteristics. This new method uses the original data without smoothing to work out an error conversion formula at the INS initial alignment time and then compensate the smoothed data errors by way of the formula at the navigation time. Both theoretical analysis and experimental results demonstrate that this method is able to cut down on computational time and raise the accuracy which makes it a better real-time compensation approach for periodic error terms of quartz micro electronic mechanical system （MEMS） gyroscope＇s zero drift.

Anti-windup Compensator Gain Design for Time-delay Systems with Constraints

Systems that are subject to both time-delay in state and input saturation are considered. We synthesize the anti-windup gain to enlarge the estimation of domain of attraction while guaranteeing the stability of the closed-loop system. An ellipsoid and a polyhedral set are used to bound the state of the system, which make a new sector condition valid. Other than an iterative algorithm, a direct designing algorithm is derived to compute the anti-windup compensator gain, which reduces the conservatism greatly. We analyze the delay-independent and delay-dependent cases, respectively. Finally, an optimization algorithm in the form of LMIs is constructed to compute the compensator gain which maximizes the estimation of domain of attraction. Numerical examples are presented to demonstrate the effectiveness of our approach.

Ballistic deficit compensation method for a large-volume HPGe detector at high count rates

A large-volume HPGe detector normally has a severe ballistic deficit due to its long rise time of the output signals.Despite the trapezoidal shaping algorithm adopted as a remedy to deal with the signals,the algorithm cannot fully eliminate the ballistic deficit in the case of a high counting rate.To resolve the problem,we propose a ballistic deficit compensation method that is based on the measurement of rise time of the signals before shaping.We find that the ballistic deficit after trapezoidal shaping has little relation to the time constant,but shows a quadratic relationship with the rise time and has a negative correlation with the shaping time.In the case of high count rates,the high resolution is handled by fitting the curve to the rise time and the amplitude deficit of the signal after shaping and by compensating for the signal amplitude after trapezoidal shaping.Tests indicate that when the count rate is about 100 kcps,the resolution of Co-60 improves from traditional 2.32 up to 1.91 keV,thus reaching a higher level.

Attenuation-compensated reverse time migration of GPR data constrained by resistivity

The high-frequency electromagnetic waves of ground-penetrating radar(GPR)attenuate severely when propagated in an underground attenuating medium owing to the influence of resistivity,which remarkably decreases the resolution of reverse time migration(RTM).As an effective high-resolution imaging method,attenuation-compensated RTM(ACRTM)can eff ectively compensate for the energy loss caused by the attenuation related to media absorption under the influence of resistivity.Therefore,constructing an accurate resistivity-media model to compensate for the attenuation of electromagnetic wave energy is crucial for realizing the ACRTM imaging of GPR data.This study proposes a resistivity-constrained ACRTM imaging method for the imaging of GPR data by adding high-density resistivity detection along the GPR survey line and combining it with its resistivity inversion profile.The proposed method uses the inversion result of apparent resistivity data as the GPR RTM-resistivity model for imposing resistivity constraints.Moreover,the hybrid method involving image minimum entropy and RTM is used to estimate the medium velocity at the diff raction position,and combined with the distribution characteristics of the reflection in the GPR profile,a highly accurate velocity model is built to improve the imaging resolution of the ACRTM.The accuracy and eff ectiveness of the proposed method are verified using the ACRTM test of the GPR simulated data of a typical attenuating media model.On this basis,the GPR and apparent resistivity data were observed on a field survey line,and use the GPR resistivity-constrained ACRTM method to image the observed data.A comparison of the proposed method with the conventional ACRTM method shows that the proposed method has better imaging depth,stronger energy,and higher resolution,and the obtained results are more conducive for subsequent data analysis and interpretation.

Stock Price Prediction Using Predictive Error Compensation Wavelet Neural Networks

:Machine Learning(ML)algorithms have been widely used for financial time series prediction and trading through bots.In this work,we propose a Predictive Error Compensated Wavelet Neural Network(PEC-WNN)ML model that improves the prediction of next day closing prices.In the proposed model we use multiple neural networks where the first one uses the closing stock prices from multiple-scale time-domain inputs.An additional network is used for error estimation to compensate and reduce the prediction error of the main network instead of using recurrence.The performance of the proposed model is evaluated using six different stock data samples in the New York stock exchange.The results have demonstrated significant improvement in forecasting accuracy in all cases when the second network is used in accordance with the first one by adding the outputs.The RMSE error is 33%improved when the proposed PEC-WNN model is used compared to the Long ShortTerm Memory(LSTM)model.Furthermore,through the analysis of training mechanisms,we found that using the updated training the performance of the proposed model is improved.The contribution of this study is the applicability of simultaneously different time frames as inputs.Cascading the predictive error compensation not only reduces the error rate but also helps in avoiding overfitting problems.

Design to conditioning circuits of dynamic compensation of reactive power in the intelligence voltage controller

The paper introduces one design idea that making use of SCM to control Real-timely the dynamic compensation of reactive power.Firstly,design one Circuit to Sample the voltage and current,and by these datas we can easily calculate the power factor,and Voltage controller in the microcontroller to determine whether input the compensation capacitance according to the size of power factor,the paper also analyzes the principle of capacitance compensation and calculation method. Dynamic compensation for the entire process is quick and accurate.

TWO NEW TYPES OF MICROWAVE RADIOMETER: A COMPUTER GAIN COMPENSATIVE DESIGN AND A REAL-TIME CALIBRATED DESIGN

Long term stability is the main factor that influences the minimum detectable signal of microwave radiometers. Two new types of microwave radiometer were studied: a computer gain compensative microwave radiometer and a real-time calibrated microwave radiometer. The long term stability of both designs was optimal because they were insensitive to system gain fluctuations. The continuous calibrated microwave radiometer was also insensitive to system noise fluctuations. The minimum detectable signals were 0.13 and 0.19K respectively under an integration time of 0.6s.

Adaptive beamforming and phase bias compensation for GNSS receiver

Adaptive antenna arrays have been used to mitigate the interference on global navigation satellite system（GNSS） receivers. The performance of interference mitigation depends on the beamforming algorithms adopted by the antenna array. However,the adaptive beamforming will change the array pattern in realtime, which has the potential to introduce phase center biases into the antenna array. For precise applications, these phase biases must be mitigated or compensated because they will bring errors in code phase and carrier phase measurements. A novel adaptive beamforming algorithm is proposed firstly, then the phase bias induced by the proposed algorithm is estimated, and finally a compensation strategy is addressed. Simulations demonstrate that the proposed beamforming algorithm suppresses effectively the strong interference and improves significantly the capturing performance of GNSS signals. Simultaneously, the bias compensation method avoids the loss of the carrier phase lock and reduces the phase measurement errors for GNSS receivers.

An Adaptive Response Compensation Technique for the Constant-Current Hot-Wire Anemometer

An adaptive response compensation technique has been proposed to compensate for the response lag of the constant-current hot-wire anemometer (CCA) by taking advantage of digital signal processing technology. First, we have developed a simple response compensation scheme based on a precise theoretical expression for the frequency response of the CCA (Kaifuku et al. 2010, 2011), and verified its effectiveness experimentally for hot-wires of 5 μm, 10 μm and 20 μm in diameter. Then, another novel technique based on a two-sensor probe technique—originally developed for the response compensation of fine-wire thermocouples (Tagawa and Ohta 1997;Tagawa et al. 1998)—has been proposed for estimating thermal time-constants of hot-wires to realize the in-situ response compensation of the CCA. To demonstrate the usefulness of the CCA, we have applied the response compensation schemes to multipoint velocity measure- ment of a turbulent wake flow formed behind a circular cylinder by using a CCA probe consisting of 16 hot-wires, which were driven simultaneously by a very simple constant-current circuit. As a result, the proposed response compensation techniques for the CCA work quite successfully and are capable of improving the response speed of the CCA to obtain reliable measurements comparable to those by the commercially-available constant-temperature hot-wire anemometer (CTA).

大时滞不确定系统的滞后时间削弱与自抗扰控制

针对具有变时滞、变参数和扰动的大时滞不确定系统的控制问题,本文提出了滞后时间削弱与自抗扰控制方法,综合应用了前馈控制、反馈控制和自抗扰补偿控制.为了提高系统的稳定性,在前馈控制器的设计中采用了系统的边界模型确定控制器参数取值范围;采用系统边界模型输出与系统实际输出的动态加权和作为反馈控制器的输入.为了提高系统控制的性能,自抗扰补偿控制回路的设计基于标称模型的补偿控制器.理论证明和仿真结果表明,所提出的方法是有效的,其在具有模型参数变化、滞后时间变化和外部扰动情况下,能保证系统的稳定性和良好的控制性能.

基于ARIMA-TCN混合模型的高速铁路时间同步方法

列控系统作为高速铁路的核心系统,保持其系统的时间同步对于行车安全至关重要。针对现有时间同步方法易受时变上下行传输时延、随机时钟跳变等影响,导致主从时钟偏移估计不准确的问题,提出一种基于差分自回归移动平均-时域卷积神经网络(ARIMA-TCN)混合模型的高速铁路时间同步方法。首先,根据上下行链路传输速率的不对称比,建立高速铁路时钟的数学理论和实际观测模型。然后,使用拉依达准则识别处理跳变异常值,完成实际时间序列的预处理。再次,使用ARIMA模型平滑时间序列中不确定时延带来的噪声抖动,获得平稳的时间序列。最后,通过提出的注意力增强TCN模型进行预测补偿,完成时钟偏移的补偿校正。通过实验仿真,得到基站区间内位置、基站间距以及车速对高速铁路时间同步的影响性分析。实验结果表明:与对比方法相比,所提方法补偿后的均方根误差较最小二乘法减少了75%、较最大似然估计方法误差减少了44.4%,较BP神经网络方法误差减少了16.7%,验证所提方法具有更低的同步误差和更高的同步精度。

COT架构Buck型转换器的纹波补偿电路

针对恒定导通时间(COT)架构的DC/DC Buck变换器,在输出电容的等效串联电阻(ESR)较小时出现的次谐波振荡问题,提出了一种纹波补偿电路,通过纹波补偿减小环路稳定性对于输出电容的大ESR的依赖,并且可通过数控电流源设置电流,从而调节补偿纹波的大小。采用提出的方法,实现了一款基于tsmc180rf工艺的DC/DC Buck变换器,其中输入电压为3.3 V,输出电压为0.9 V,带负载能力为1.5 A。实验结果显示,应用此方法的转换器,其输出电压纹波仅为2.4 mV。该方法可以在保证环路稳定性的同时,避免过补偿,为DC/DC转换器的纹波补偿设计提供了新的思路。