Research on Anti-Fluctuation Control of Winding Tension System Based on Feedforward Compensation

In the fiber winding process,strong disturbance,uncertainty,strong coupling,and fiber friction complicate the winding constant tension control.In order to effectively reduce the influence of these problems on the tension output,this paper proposed a tension fluctuation rejection strategy based on feedforward compensation.In addition to the bias harmonic curve of the unknown state,the tension fluctuation also contains the influence of bounded noise.A tension fluctuation observer(TFO)is designed to cancel the uncertain periodic signal,in which the frequency generator is used to estimate the critical parameter information.Then,the fluctuation signal is reconstructed by a third-order auxiliary filter.The estimated signal feedforward compensates for the actual tension fluctuation.Furthermore,a time-varying parameters fractional-order PID controller(TPFOPID)is realized to attenuate the bounded noise in the fluctuation.Finally,TPFOPID is enhanced by TFO and applied to control a tension control system considering multi-source disturbances.The stability of the method is analyzed by using the Lyapunov theorem.Finally,numerical simulations verify that the proposed scheme improves the tracking ability and robustness of the system in response to tension fluctuations.

Adaptive Robust Servo Control for Vertical Electric Stabilization System of Tank and Experimental Validation

A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevarying but bounded uncertainty within the vertical electric stabilization system:model parameter uncertainty and uncertain nonlinearity.First,the vertical electric stabilization system is constructed as an uncertain nonlinear dynamic system that can reflect the practical mechanics transfer process of the system.Second,the dynamical equation in the form of state space is established by designing the angular tracking error.Third,the comprehensive parameter of system uncertainty is designed to estimate the most conservative effects of uncertainty.Finally,an adaptive robust servo control which can effectively handle the combined effects of complex nonlinearity and uncertainty is proposed.The feasibility of the proposed control strategy under the practical physical condition is validated through the tests on the experimental platform.This paper pioneers the introduction of the internal nonlinearity and uncertainty of the vertical electric stabilization system into the settlement of the tracking stability control problem,and validates the advanced servo control strategy through experiment for the first time.

Tailoring-compensated ferrimagnetic state and anomalous Hall effect in quaternary Mn–Ru–V–Ga Heusler compounds

Cubic Mn_(2)Ru_(x)Ga Heusler compound is a typical example of compensated ferrimagnet with attractive potential for high-density,ultrafast,and low-power spintronic applications.In the form of epitaxial thin films,Mn_(2)Ru_(x)Ga exhibits high spin polarization and high tunability of compensation temperature by freely changing the Ru content x in a broad range(0.3<x<1.0).Herein Mn-Ru-Ga-based polycrystalline bulk buttons prepared by arc melting are systematically studied and it is found that in equilibrium bulk form,the cubic structure is unstable when x<0.75.To overcome this limitation,Mn-Ru-Ga is alloyed with a fourth element V.By adjusting the content of V in the By adjusting the content of V in the Mn_(2)Ru_(0.75)V_(y)Ga and Mn_(2.25-y)Ru_(0.75)V_(y)Ga quaternary systems the magnetic compensation temperature is tuned.Compensation is achieved near 300 K which is confirmed by both the magnetic measurement and anomalous Hall effect measurement.The analyses of the anomalous Hall effect scaling in quaternary Mn-Ru-V-Ga alloy reveal the dominant role of skew scattering,notably that contributed caused by the thermally excited phonons,in contrast to the dominant intrinsic mechanism found in many other 3d ferromagnets and Heusler compounds.It is further shown that the Ga antisites and V content can simultaneously control the residual resistivity ratio(RRR)as well as the relative contribution of phonon and defect to the anomalous Hall effect a"/a0'in Mn-Ru-V-Ga,resulting in a scaling relation a"/a0'∝RRR^(1.8).

Primary frequency control considering communication delay for grid-connected offshore wind power systems

Offshore wind farms are becoming increasingly distant from onshore centralized control centers,and the communication delays between them inevitably introduce time delays in the measurement signal of the primary frequency control.This causes a deterioration in the performance of the primary frequency control and,in some cases,may even result in frequency instability within the power system.Therefore,a frequency response model that incorporates communication delays was established for power systems that integrate offshore wind power.The Padéapproximation was used to model the time delays,and a linearized frequency response model of the power system was derived to investigate the frequency stability under different time delays.The influences of the wind power proportion and frequency control parameters on the system frequency stability were explored.In addition,a Smith delay compensation control strategy was devised to mitigate the effects of communication delays on the system frequency dynamics.Finally,a power system incorporating offshore wind power was constructed using the MATLAB/Simulink platform.The simulation results demonstrate the effectiveness and robustness of the proposed delay compensation control strategy.

Force Compensation Control for Electro-Hydraulic Servo System with Pump-Valve Compound Drive via QFT-DTOC

Each joint of a hydraulic-driven legged robot adopts a highly integrated hydraulic drive unit(HDU),which features a high power-weight ratio.However,most HDUs are throttling-valve-controlled cylinder systems,which exhibit high energy losses.By contrast,pump control systems offer a high efficiency.Nevertheless,their response ability is unsatisfactory.To fully utilize the advantages of pump and valve control systems,in this study,a new type of pump-valve compound drive system(PCDS)is designed,which can not only effectively reduce the energy loss,but can also ensure the response speed and response accuracy of the HDUs in robot joints to satisfy the performance requirements of robots.Herein,considering the force control requirements of energy conservation,high precision,and fast response of the robot joint HDU,a nonlinear mathematical model of the PCDS force control system is first introduced.In addition,pressure-flow nonlinearity,friction nonlinearity,load complexity and variability,and other factors affecting the system are considered,and a novel force control method based on quantitative feedback theory(QFT)and a disturbance torque observer(DTO)is designed,which is denoted as QFT-DTOC herein.This method improves the control accuracy and robustness of the force control system,reduces the effect of the disturbance torque on the control performance of the servo motor,and improves the overall force control performance of the system.Finally,experimental verification is performed using the PCDS performance test platform.The experimental results and quantitative data show that the QFT-DTOC proposed herein can significantly improve the force control performance of the PCDS.The relevant force control method can be used as a bottom-control method for the hydraulic servo system to provide a foundation for implementing the top-level trajectory planning of the robot.

A frequency domain estimation and compensation method for system synchronization parameters of distributed-HFSWR

To analyze the influence of time synchronization error,phase synchronization error,frequency synchronization error,internal delay of the transceiver system,and range error and angle error between the unit radars on the target detection performance,firstly,a spatial detection model of distributed high-frequency surface wave radar(distributed-HFSWR)is established in this paper.In this model,a method for accurate extraction of direct wave spectrum based on curve fitting is proposed to obtain accurate system internal delay and frequency synchronization error under complex electromagnetic environment background and low signal to noise ratio(SNR),and to compensate for the shift of range and Doppler frequency caused by time-frequency synchronization error.The direct wave component is extracted from the spectrum,the range estimation error and Doppler estimation error are reduced by the method of curve fitting,and the fitting accuracy of the parameters is improved.Then,the influence of frequency synchronization error on target range and radial Doppler velocity is quantitatively analyzed.The relationship between frequency synchronization error and radial Doppler velocity shift and range shift is given.Finally,the system synchronization parameters of the trial distributed-HFSWR are obtained by the proposed spectrum extraction method based on curve fitting,the experimental data is compensated to correct the shift of the target,and finally the correct target parameter information is obtained.Simulations and experimental results demonstrate the superiority and correctness of the proposed method,theoretical derivation and detection model proposed in this paper.

Trajectory compensation for multi-robot coordinated lifting system considering elastic catenary of the rope

The multi-robot coordinated lifting system is an unconstrained system with a rigid and flexible coupling.The deformation of the flexible rope causes errors in the movement trajectory of the lifting system.Based on the kinematic and dynamic analysis of the lifting system,the elastic catenary mod-el considering the elasticity and mass of the flexible rope is established,and the effect of the deform-ation of the flexible rope on the position and posture of the suspended object is analyzed.According to the deformation of flexible rope,a real-time trajectory compensation method is proposed based on the compensation principle of position and posture.Under the lifting task of the low-speed move-ment,this is compared with that of the system which neglects the deformation of the flexible rope.The trajectoy of the lifting system considering the deformation of flexible rope.The results show that the mass and elasticity of the flexible rope can not be neglected.Meanwhile,the proposed trajectory compensation method can improve the movement accuracy of the lifting system,which verifies the ef-fectiveness of this compensation method.The research results provide the basis for trajectory plan-ning and coordinated control of the lifting system。

Low level of hepatitis B viremia is associated with increased risk of hepatocellular carcinoma in compensated cirrhotic patients

BACKGROUND Whether patients with compensated cirrhosis and low-level viremia(LLV)of hepatitis B should receive antiviral therapy(AVT)is still controversial,and published results are inconsistent.AIM To investigate the link between LLV in compensated cirrhosis and prognosis concerning hepatocellular carcinoma(HCC),decompensation,and liver-related events.METHODS The PubMed,EMBASE,and Cochrane Library databases were searched up to March 5,2023.Outcomes of interest were assessed by pooled hazard ratios(HRs).The study was registered with PROSPERO(CRD42023405345).RESULTS Six cohort studies representing 3155 patients were included.Compared with patients with undetectable HBV DNA,patients with LLV was associated with increased risk of HCC(HR:2.06,95%CI:1.36-3.13;Q-statistic-P=0.07,I^(2)=51%)regardless of receiving AVT or not(AVT group:HR:3.14;95%CI:1.73-5.69;Qstatistic-P=0.60,I2=0%;un-AVT group:HR:1.73,95%CI:1.09-2.76;Q-statistic-P=0.11,I2=50%).The pooled results showed no statistical association between LLV and decompensation of cirrhosis(HR:2.06,95%CI:0.89-4.76;Q-statistic-P=0.04,I2=69%),and liver-related events(HR:1.84,95%CI:0.92-3.67;Q-statistic-P=0.03,I2=72%),respectively.Grading of Recommendations Assessment,Development and Evaluation assessment indicated moderate certainty for HCC,very low certainty for decompensation of cirrhosis and liver-related clinical events.CONCLUSION LLV in compensated cirrhotic patients is associated with increased risk of HCC,higher tendency for hepatic decompensation and liver-related events.Closer screening of HCC should be conducted in this population.

Exploring Efficient Salary Management Systems:A Case Study of Hefei Yusheng Hotel Management Co.,Ltd.

The issue of brain drain poses a significant obstacle to the development of the hotel and catering industry.Attracting and retaining skilled personnel to engage in management within this sector has emerged as a primary challenge.This paper examines the current landscape of China’s catering service industry and its salary management system,identifying key challenges encountered in salary management within the industry.Drawing upon salary management theory and insights into existing challenges,the paper proposes specific treatment measures and management strategies.

Transformer for the Design of Automatic Control Systems with Prefilters

A machine learning model, using the transformer architecture, is used to design a feedback compensator and prefilter for various simulated plants. The output of the transformer is a sequence of compensator and prefilter parameters. The compensator and prefilter are linear models, preserving the ability to analyze the system with linear control theory. The input to the network is a window of recent reference and output samples. The goal of the transformer is to minimize tracking error at each time step. The plants under consideration range from simple to challenging. The more difficult plants contain closely spaced, lightly damped, complex conjugate pairs of poles and zeros. Results are compared to PID controllers tuned for a similar crossover frequency and optimal phase margin. For simple plants, the transformer converges to solutions which overly rely on the prefilter, neglecting the maximization of negative feedback. For more complex plants, the transformer designs a compensator and prefilter with more desirable qualities. In all cases, the transformer can start with random model parameters and modify them to minimize tracking error on the step reference.

Observer Based Control for a Class of Systems with Output Deadzone Nonlinearity

In this paper, a combination of model based adaptive design along with adaptive linear output feedback controller is used to compensate for robotic manipulator with output deadzone nonlinearity. The deadzone dynamics are utilized to adaptively estimate the deadzone parameter and a switching function is designed to eliminate the error produced in the adaptive observer dynamics. The overall design of the closed loop system ensures stability in the BIBO criterion.

Salvia Polyphenolates Combined with Doxophylline in the Treatment of Patients with Chronic Pulmonary Heart Disease in the Compensated Stage

Objective:To statistically determine the effect of salvia polyphenolates combined with doxophylline treatment in patients with chronic pulmonary heart disease in the compensated stage.Methods:From January 2023 to January 2024,76 patients with chronic pulmonary heart disease in the compensated stage were selected as research subjects.The patients were divided into a research group and a reference group using a randomized numerical table method.The research group was treated with salvia polyphenolates combined with doxophylline,while the reference group received conventional therapy.The treatment effects of the two groups were compared.Results:The patients in the research group,treated with salvia polyphenolates combined with doxophylline,showed maximal ventilation of 73.26±4.83 L/min,left ventricular ejection fraction of 56.14±1.98%,and total effective treatment rate of 94.74%.These results were better than those of the reference group.The differences between the data of the research group and the reference group were statistically significant(P<0.05).Conclusion:For patients with chronic pulmonary heart disease in the compensated stage,treatment with salvia polyphenolates combined with doxophylline significantly improves maximum ventilation and left ventricular ejection fraction,and also results in a higher total effective treatment rate.

PRESSURE COMPENSATION METHOD OF UNDERWATER HYDRAULIC SYSTEM WITH HYDRAULIC POWER UNIT BEING UNDER ATMOSPHERIC CIRCUMSTANCE AND PRESSURE COMPENSATED VALVE

Based on the analysis of the-state-of-the-art of pressure compensation of underwater hydraulic systems （UHSs）, a new method of pressure compensation of UHSs, whose hydraulic power unit is in the atmospheric circumstance, is proposed. And a pilot-operated relief valve with pressure compensation is realized. The pressure compensation precision is guaranteed by direct detection. Its dynamic performance and stability are improved by a dynamic feedback. Theoretical study, simulation and experiment show that the pilot-operated relief valve with pressure compensation has a fine property of tracking underwater ambient pressure and meet the requirement of underwater ambient pressure compensation.

Validation of the albumin-bilirubin score for identifying decompensation risk in patients with compensated cirrhosis

BACKGROUND The albumin-bilirubin(ALBI)score is an index of liver function recently developed to assess prognosis in patients with hepatocellular carcinoma(HCC).It can detect small changes in liver dysfunction and has been successfully applied to the prediction of survival in patients with non-malignant liver diseases of various etiologies.AIM To investigate the ALBI score for identifying decompensation risk at the 3-year follow-up in patients with compensated cirrhosis.METHODS One-hundred and twenty-three patients with compensated cirrhosis without HCC in King Chulalongkorn Memorial Hospital diagnosed by imaging were retrospectively enrolled from January 2016 to December 2020.A total of 113 patients(91.9%)had Child A cirrhosis with a median model for end-stage liver disease(MELD)score of less than 9.Baseline clinical and laboratory variables and decompensation events were collected.The ALBI score was calculated and validated to classify decompensation risk into low-,middle-,and high-risk groups using three ALBI grade ranges(ALBI grade 1:≤-2.60;grade 2:>-2.60 but≤-1.39;grade 3:>-1.39).Decompensation events were defined as ascites development,variceal bleeding,or grade 3 or 4 hepatic encephalopathy.RESULTS Among 123 cirrhotic patients enrolled,13.8%(n=17)developed decompensating events at a median time of 25[95%confidence interval(CI):17-31]mo.Median baseline ALBI score in compensated cirrhosis was significantly lower than that of patients who developed decompensation events[-2.768(-2.956 to-2.453)vs-2.007(-2.533 to-1.537);P=0.01].Analysis of decompensation risk at 3 years showed that ALBI score had a time-dependent area under the curve(tAUC)of 0.86(95%CI:0.78-0.92),which was significantly better than that of ALBI-Fibrosis-4(ALBI-FIB4)score(tAUC=0.77),MELD score(tAUC=0.66),Child-Pugh score(tAUC=0.65),and FIB-4 score(tAUC=0.48)(P<0.05 for all).The 3-year cumulative incidence of decompensation was 3.1%,22.6%,and 50%in the low-,middle-,and high-risk groups,respectively(P<0.001).The odds ratio for decompensation in patients of the high-risk group was 23.33(95%CI:3.88-140.12,P=0.001).CONCLUSION The ALBI score accurately identifies decompensation risk at the 3-year follow-up in patients with compensated cirrhosis.Those cirrhotic patients with a high-risk grade of ALBI score showed a 23 times greater odds of decompensation.

Research on the Sub-synchronous Oscillation in Wind Power Connected to Series Compensated Power System and its Influencing Factors

When wind farms,which is based on double fed induction generator(DFIG),are connected to the series compensation power system,the phenomenon of sub-synchronous oscillation(SSO)may occur.In order to study the sub-synchronous oscillation in wind power connected to series compensated power system and its influencing factors,we used RT-LAB to establish a simulation model concerning wind power connected to series-compensation power system.This model take a wind power connected to series compensation power system in north China as prototype.All influence factors of wind power SSO are simulated and analyzed by using time domain analysis method.The simulation results show that the effects of wind speed,series compensation degree and proportional control coefficient of rotor side converter(RSC)are most obvious.

Excavation compensation theory and supplementary technology system for large deformation disasters

Given the challenges in managing large deformation disasters in energy engineering,traffic tunnel engineering,and slope engineering,the excavation compensation theory has been proposed for large deformation disasters and the supplementary technology system is developed accordingly.This theory is based on the concept that“all destructive behaviors in tunnel engineering originate from excavation.”This paper summarizes the development of the excavation compensation theory in five aspects:the“theory,”“equipment,”“technology,”the design method with large deformation mechanics,and engineering applications.First,the calculation method for compensation force has been developed based on this theory,and a comprehensive large deformation disaster control theory system is formed.Second,a negative Poisson's ratio anchor cable with high preload,large deformation,and super energy absorption characteristics has been independently developed and applied to large deformation disaster control.An intelligent tunnel monitoring and early warning cloud platform system are established for remote monitoring and early warning system of Newton force in landslide geological hazards.Third,the double gradient advance grouting technology,the two-dimensional blasting technology,and the integrated Newton force monitoring--early warning--control technology are developed for different engineering environments.Finally,some applications of this theory in China's energy,traffic tunnels,landslide,and other field projects have been analyzed,which successfully demonstrates the capability of this theory in large deformation disaster control.

Compensated liver cirrhosis:Natural course and disease-modifying strategies

Compensated liver cirrhosis(CLC)is defined as cirrhosis with one or more decompensating events,such as ascites,variceal haemorrhage,or hepatic encephalopathy.Patients with CLC are largely asymptomatic with preserved hepatic function.The transition from CLC to decompensated cirrhosis occurs as a result of a complex interaction between multiple predisposing and precipitating factors.The first decompensation event in CLC patients is considered a significant turning point in the progression of cirrhosis,as it signals a drastic decline in median survival rates from 10-12 years to only 1-2 years.Furthermore,early cirrhosis has the potential to regress as liver fibrosis is a dynamic condition.With the advent of effective non-invasive tools for detecting hepatic fibrosis,more and more patients with CLC are currently being recognised.This offers clinicians a unique opportunity to properly manage such patients in order to achieve cirrhosis regression or,at the very least,prevent its progression.There are numerous emerging approaches for preventing or delaying decompensation in CLC patients.A growing body of evidence indicates that treating the underlying cause can lead to cirrhosis regression,and the use of non-selective beta-blockers can prevent decompensation by lowering portal hypertension.Additionally,address-ing various cofactors(such as obesity,diabetes,dyslipidaemia,and alcoholism)and precipitating factors(such as infection,viral hepatitis,and hepatotoxic drugs)that have a detrimental impact on the natural course of cirrhosis may benefit patients with CLC.However,high-quality data must be generated through well-designed and adequately powered randomised clinical trials to validate these diseasemodifying techniques for CLC patients.This article discussed the natural history of CLC,risk factors for its progression,and therapeutic approaches that could alter the trajectory of CLC evolution and improve outcomes.

Compensated methods for networked control system with packet drops based on compressed sensing

Due to unreliable and bandwidth-limited characteristics of communication link in networked control systems,the realtime compensated methods for single-output systems and multioutput systems are proposed in this paper based on the compressed sensing(CS)theory and sliding window technique,by which the estimates of dropping data packets in the feedback channel are obtained and the performance degradation induced by packet drops is reduced.Specifically,in order to reduce the cumulative error caused by the algorithm,the compensated estimates for single-output systems are corrected via the regularization term;considering the process of single-packet transmission,a new sequential CS framework of sensor data streams is introduced to effectively compensate the dropping packet on single-channel of multi-output systems;in presence of the medium access constraints on multi-channel,the communication sequence for scheduling is coupled to the algorithm and the estimates of the multiple sensors for multi-output systems are obtained via the regularization term.Simulation results illustrate that the proposed methods perform well and receive satisfactory performance.

Large PMD Compensated by Four Free Degrees in OTDM System

By introducing a two-stage polarization mode dispersion (PMD) compensator after a optical fiber link with a large PMD,over 270 ps first-order and 2 000 ps^2 high-order PMD was compensated.The results show that the two-stage compensator can be used to PMD compensation in the 20 Gb/s optical time division multiplexing system with 60 km high PMD fiber.After compensating,the 270 ps DGD is changed into max.7 ps.Moreover,the tunable FBG has a function of dispersion compensation.

Strain compensated type Ⅱ superlattices grown by molecular beam epitaxy

We investigate a strain compensation method for the growth of complex interband cascade laser structures. For thick In As/Al Sb superlattice clad layers, the sublayer thicknesses were adjusted so that the tensile strain energy in the In As sublayer was equal to the compressive strain energy in the Al Sb sublayer. For the four-constituent active region, as the compressive strain in the Ga0.65In0.35Sb alloy layer was large, a tensile strain was incorporated in the chirped In As/Al Sb superlattice region for strain compensation to the Ga0.65In0.35Sb alloy. A laser structure of thickness 6 μm was grown on the Ga Sb substrate by molecular beam epitaxy. The wafer exhibited good surface morphology and high crystalline quality.