Hysteresis Problem Research Articles

Hysteresis modeling and experimental research of pneumatic constant force grinding system based on GRU neural network

The pneumatic constant force grinding system has attracted a lot of attention in the fields of robot grinding. However, the hysteresis behavior of the pneumatic constant force grinding system has multi-valued mapping characteristics and dynamic characteristics related to the frequency and amplitude of the input signal. Aiming at the hysteresis problem of pneumatic constant force device, a gated recurrent unit neural network (GRU) modeling method based on Bayesian optimization is proposed, and the effectiveness of the modeling method is verified by experiments. The ability of the model to describe the hysteresis behavior of the system and the force control performance and polishing effect based on the model are analyzed by experiments. The results show that the GRU model has better description ability for the hysteresis behavior related to amplitude and frequency than the rational Bezier curve fitting method (BCM). Through the grinding test, it can be seen that the output constant force fluctuation range based on the GRU neural network model is −1 ~ 1 N. With the increase of the grinding force, the surface roughness and morphology of the specimen are improved, and the average surface roughness is reduced by 23.79 % at most.

CSTR parameter identification and PID control optimization based on improved swarm intelligence algorithm

Abstract Aiming at the problems of strong coupling and large hysteresis that exist in the production process of a typical thermal object continuous stirred reactor (CSTR), which make it difficult to recognize the system model parameters and control the temperature, an improved firefly algorithm is proposed to recognize the system parameters, and its recognition accuracy is higher than that of the original firefly algorithm; and an improved sparrow search algorithm (BCGSSA) is used to control the temperature of the CSTR system by combining the BCGSSA algorithm with PID control, which significantly improves the dynamic performance of the CSTR system. Then an improved sparrow search algorithm (BCGSSA) is combined with PID control to control the temperature of the CSTR system, which significantly improves the dynamic performance of the CSTR, and the improved algorithm (BCGSSA) has good control accuracy and robustness.

Optimal Path of Education Based on Individual Differences of Students and Hysteresis of Education

Abstract: The problem of educational hysteresis was proposed decades ago, but effective solutions have been rare. In this paper, an analysis of the causes and effects of educational hysteresis, along with finding the correlation between individual differences of students with educational development has been done. Based on the analysis, the hysteresis of education originates from timeline conflicts, reform difficulties, and teachers' acceptability towards new content. These would result in losing the purpose of education: helping students prepare for future careers and maintain equality. This essay also points out the differences in children between different generations, and how students can change in many different aspects like thinking and values. Based on these conclusions, this paper argues that the government should constantly update its system and set specific reform goals for different areas. Teachers should focus on creating opportunities from time to time, incorporating innovations in teaching methods. In addition, teachers should pay attention to the situation of students and achieve personalized teaching.

Smith GA-PID feedback control of hot strip final rolling temperature

Abstract At present, the hot strip finishing temperature control system generally adopts a computer model or mechanism model to predict the strip’s final rolling temperature, which is open-loop control. To realize the precise control of the final rolling temperature of high-performance steel, this paper introduces the PID feedback control strategy at the end of the finishing zone, to realize the high-precision temperature control of the strip steel. The Smith compensator is used to predict the compensation for the large hysteresis problem of the final rolling temperature, and various intelligent algorithms are used to optimize the three parameters of the PID controller, eliminate the nonlinear problem, and obtain better dynamic performance. After the experiment, it is concluded that the Smith GA-PID optimization control strategy system has a small overshoot, the peak time and regulation time are the shortest, and the dynamic response is the fastest. Compared with the traditional PID control method, the overshoot is reduced by 97.6%, and the required regulation time is reduced by 7.85 s.

Coupled hysteresis and resonance control of three-degree-of-freedom tip-tilt-piston piezoelectric stage

In order to solve the coupled hysteresis and resonance problems in three-degree-of-freedom tip-tilt-piston piezoelectric stage, a coupled hysteresis model and a coupled integral resonance compensation model are designed. The inverse coupled hysteresis feedforward control combined multi-axis coupled resonance control and high-gain integral tracking controller are used to improve the tracking speed and positioning accuracy of the stage. Firstly, a kinematic model of the stage is built to translate the three-degree-of-freedom motion of the end-effector into the outputs of three piezoelectric actuators. Then, a coupled hysteresis model based on the rate-dependent Prandtl–Ishlinskii model is established and parameterized to simultaneously compensate for the hysteresis of a single piezoelectric actuator and the coupled hysteresis between multiple piezoelectric actuators. The effectiveness of the model is verified by open-loop and closed-loop inverse model feedforward control experiments. Afterwards, a coupled integral resonance compensation model is also established and parameterized to suppresses the resonance and expand the system bandwidth. Finally, the proposed controller is used to conduct tracking experiments on a composite signal, and the results show that the accuracy and speed of trajectory tracking are further improved, and the mechanical coupling between axes are significantly reduced.

A Data-Driven Model with Hysteresis Compensation for I2RIS Robot.

Retinal microsurgery is a high-precision surgery performed on a delicate tissue requiring the skill of highly trained surgeons. Given the restricted range of instrument motion in the confined intraocular space, snake-like robots may prove to be a promising technology to provide surgeons with greater flexibility, dexterity, and positioning accuracy during retinal procedures such as retinal vein cannulation and epiretinal membrane peeling. Kinematics modeling of these robots is an essential step toward accurate position control. Unlike conventional manipulators, modeling these robots does not follow a straightforward method due to their complex mechanical structure and actuation mechanisms. The hysteresis problem can especially impact the positioning accuracy significantly in wire-driven snake-like robots. In this paper, we propose a data-driven kinematics model using a probabilistic Gaussian mixture model (GMM) and Gaussian mixture regression (GMR) approach with a hysteresis compensation algorithm. Experimental results on the two-degree-of-freedom (DOF) integrated robotic intraocular snake (I2RIS) show that the proposed model with the hysteresis compensation can predict the snake tip bending angle for pitch and yaw with 0.45° and 0.39° root mean square error (RMSE), respectively. This results in overall 60% and 70% improvements of accuracy for yaw and pitch over the same model without the hysteresis compensation.

Reducing Voltage Hysteresis in Li-Rich Sulfide Cathodes by Incorporation of Mn.

Conventional intercalation-based cathode materials in Li-ion batteries are based on charge compensation of the redox-active cation and can only intercalate one mole of electron per formula unit. Anion redox, which employs the anion sublattice to compensate charge, is a promising way to achieve multielectron cathode materials. Most anion redox materials still face the problems of slow kinetics and large voltage hysteresis. One potential solution to reduce voltage hysteresis is to increase the covalency of the metal-ligand bonds. By substituting Mn into the electrochemically inert Li1.33Ti0.67S2 (Li2TiS3), anion redox can be activated in the Li1.33-2y/3Ti0.67-y/3Mn y S2 (y = 0-0.5) series. Not only do we observe substantial anion redox, but the voltage hysteresis is significantly reduced, and the rate capability is dramatically enhanced. The y = 0.3 phase exhibits excellent rate and cycling performance, maintaining 90% of the C/10 capacity at 1C, which indicates fast kinetics for anion redox. X-ray absorption spectroscopy (XAS) shows that both the cation and anion redox processes contribute to the charge compensation. We attribute the drop in hysteresis and increase in rate performance to the increased covalency between the metal and the anion. Electrochemical signatures suggest the anion redox mechanism resembles holes on the anion, but the S K-edge XAS data confirm persulfide formation. The mechanism of anion redox shows that forming persulfides can be a low hysteresis, high rate capability mechanism enabled by the appropriate metal-ligand covalency. This work provides insights into how to design cathode materials with anion redox to achieve fast kinetics and low voltage hysteresis.

Experimental and theoretical study of the harmonic distortion in a ferromagnetic plate excited by a pair of air-cored coils

The harmonic distortion in a ferromagnetic plate is studied both experimentally and using numerical simulations. The electromagnetic field inside the specimen is excited by a couple of air-cored coils, and the field is measured at a specific location using a set of Hall sensors. The considered material is a typical structural steel of an intermediate mechanical and magnetic hardness. The comparison of the numerical results with carefully conducted measurements demonstrates the importance of an accurate and physically consistent hysteresis model. The absence of magnetic circuit reduces the number of the setup uncertainties thereby simplifying the characterisation procedure and making this particular configuration a good benchmark candidate for the validation of numerical codes dealing with the hysteresis problem.

ZIF-8 modified the anode of the magnesium battery to improve the problems of voltage hysteresis and corrosion resistance

Magnesium is a promising anode material. However, the magnesium anode will quickly react with the electrolyte to form an ion-insulated passivation film, resulting in voltage hysteresis. Because the magnesium anode is easily corroded, it leads to a decrease in its electrochemical performance. In this paper, the anode of the magnesium battery was modified by ZIF-8 coating. The ZIF-8 coating can largely prevent contact between water in the solution and the surface of the magnesium anode, which can inhibit the passivation of the magnesium anode. The voltage hysteresis time is significantly reduced from 4 s before modification to 0.3 s, which also effectively reduces the resistance of the battery. Compared with the unmodified magnesium battery, the modified magnesium battery has a larger initial voltage and a longer discharge platform. The anode utilization rate is doubled compared with that before modification, and the specific energy density is also greatly improved. The ZIF-8 coating with porous network structure and hydrophobicity can slow down the infiltration of corrosive substances to some degree, prolong its transmission path, and provide better protection for the magnesium anode.

Attention-based early warning framework for abnormal operating conditions in fluid catalytic cracking units

Fluid Catalytic Cracking Unit (FCCU) is a critical processing technology in the oil refining industry, playing a vital role in energy efficiency and environmental protection. However, FCCU often encounters various abnormal operating conditions, leading to safety hazards, downtime, and reduced production efficiency. Early warning of these abnormal conditions is crucial but challenging due to high noise, strong hysteresis, and class imbalance problems. To tackle these challenges, a novel and universal attention-based framework called AEW-AOC (Attention-based Early Warning for Abnormal Operating Conditions) is specifically designed for FCCU applications. The proposed AEW-AOC framework incorporates three key components: (1) a Self-Correlation Denoiser (SCD) module is proposed to exploit spatiotemporal data correlation to effectively reduce noise; (2) a Convolutional Long Short-Term Memory (Conv-LSTM) module is employed to address the issue of strong hysteresis by capturing temporal variation features of process parameters; (3) an Anomaly Pattern Attention (APA) module is proposed to enhance the distinguishability of abnormal operating conditions based on clustering results from historical abnormal instances. Extensive experiments demonstrate the effectiveness and superiority of the proposed AEW-AOC framework, particularly in practical applications. Specifically, the AEW-AOC framework obtains an impressive fβ score of 91.00% on LIC201, 90.45% on LIC202, and 90.64% on LIC801. The proposed AEW-AOC framework shows great potential in enhancing safety, reducing downtime, optimizing efficiency, promoting sustainability, and expanding its applicability beyond FCCU. Its proactive and versatile nature makes it a valuable tool for improving industrial processes and driving advancements in the field of abnormal operating condition detection and prevention.

Research on measurement error calibration method of TDLAS oxygen concentration detection based on CFD and SVR

Tunable Diode Laser Absorption Spectroscopy (TDLAS) enables rapid online detection of gas concentrations through the absorption of spectral lines by gas molecules in the infrared spectral region. In order to solve the problem of hysteresis and large errors of the measured values relative to the true values when TDLAS detects gases with simultaneous changes in oxygen concentration and flow rate in real-time, the CFD simulation model of the absorption cell is established by Fluent. The relationship between the measured value of TDLAS and the actual concentration change under different flow conditions is analyzed by simulation data, and the support vector machine regression calibration model is established to reduce the measurement error. It successfully reduces the average error from 5.844% to 2.899%, which is a reduction of 50.7%. The average error is further reduced to 1.308% after a secondary calibration based on different starting concentrations. The method is suitable for concentration detection in the presence of rapid changes in oxygen concentration.

Simulation Design of Level Cascade Control System for Double-capacity Water Tanks

As a typical representative of process control, double-capacity water tank level control is a common automation control system used to control the level of two tanks to achieve level stabilisation and control, which is widely used in various fields of industrial production. Liquid level control is the key to the performance of the whole control system due to the existence of hysteresis and other problems in the control. Serial control of the sub-loop has a rapid control role, it can effectively overcome the impact of the disturbance into the sub-loop, improve the dynamic characteristics of the object, so in order to achieve better control performance, this design uses serial control to achieve the level of double-capacity water tank fixed value control. Double-capacity water tank level series control system to the tank level as the controlled quantity, first of all, the characteristics of the tank, the establishment of its mathematical modelling, and then the use of MATLAB on the simulation of the tank as well as PID parameter adjustment, and finally through the response curve to analyze the control performance of the system. The simulation results show that the double-capacity water tank level series control performance is good, the system can achieve the level of static-free regulation, and anti-interference ability is strong, with good dynamic and steady state performance.

Modeling and invariably horizontal control for the parallel mobile rescue robot based on PSO-CPG algorithm

AbstractA walking robot consisting of double Stewarts parallel legs was designed by our research team in the past time, which was mainly used for the transportation of the wounded after the disaster. In order to promote stability of control locomotion and ensure invariably horizontal state of the robot platform in the process of motion, the central pattern generator (CPG) based on particle swarm optimization (PSO) is presented to optimize the kinematic model. The purpose of optimization is to solve the hysteresis problem of displacement variation among the electric cylinders. Moreover, the dynamic model of the robot is established, which can provide mechanical basis for the feedback of control signal and make the robot move stably. The simulation results show that the displacement hysteresis problem of the electric cylinders is solved well. Meanwhile, compared with simulation results based on GA-CPG method, it is demonstrated that the robot motion planned using PSO-CPG method has better motion stability and can avoid the impact of legs landing during the transition phase of the motion cycle. The experimental results show that the platform on the robot can maintain an invariably horizontal state, and the locomotion is more stable. It verifies the feasibility of PSO-CPG model and the correctness of the dynamic model of the parallel mobile rescue robot.

Converging PMF Calculations of Antibiotic Permeation across an Outer Membrane Porin with Subkilocalorie per Mole Accuracy.

The emergence of multidrug-resistant pathogens led to a critical need for new antibiotics. A key property of effective antibiotics against Gram-negative bacteria is their ability to permeate through the bacterial outer membrane via transmembrane porin proteins. Molecular dynamics (MD) simulations are, in principle, capable of modeling antibiotic permeation across outer membrane porins (OMPs). However, owing to sampling problems, it has remained challenging to obtain converged potentials of mean force (PMFs) for antibiotic permeation across OMPs. Here, we investigated the convergence of PMFs along a single collective variable aimed at quantifying the permeation of the antibiotic fosmidomycin across the OprO porin. We compared standard umbrella sampling (US) with three advanced flavors of the US technique: (i) Hamiltonian replica exchange with solute tempering in combination with US, (ii) simulated tempering-enhanced US, and (iii) replica-exchange US. To quantify the PMF convergence and to reveal hysteresis problems, we computed several independent sets of US simulations starting from pulling simulations in the outward and inward permeation directions. We find that replica-exchange US in combination with well-chosen restraints is highly successful for obtaining converged PMFs of fosmidomycin permeation through OprO, reaching PMFs converged to subkilocalorie per mole accuracy.

RISC-V-Based Evaluation and Strategy Exploration of MRAM Triple-Level Hybrid Cache Systems

Magnetic random access memory (MRAM) is considered one of the most promising memories among nonvolatile memories (NVMs), to replace static random access memory (SRAM) in the computing system to improve its cache performance. In this article, performance evaluation and strategy exploration of three-level hybrid cache systems are conducted under the framework of Reduced InstrucTIon Set Computer-Five (RISC-V) instruction set. First, system-level joint calls of Nvsim, Gem5, McPAT, and other cache emulation architectures are implemented based on the system-level simulator called MAGPIE tool. Based on the performance comparison of spin transfer torque (STT)-MRAM, spin-orbit torque (SOT)-MRAM, and SRAM with varied capacities, a variety of combined CPU three-level hybrid cache architectures are simulated. The performances of the proposed hybrid cache systems and the bus impact of interconnecting are evaluated, with better analysis of the cost of CPU system implementation and interactions among levels of cache. The power consumption of different processors with various instruction sets and cores is also evaluated. It is demonstrated that SOT-MRAM and STT-MRAM show great potential applications as L2 and L3 caches in the RISC-V system. RISC-V shows the potential benefits for future CPU cache. Meanwhile, an adaptive stride prefetching strategy is proposed to address the problem of delay hysteresis and high miss rate of STT-MRAM in the L3 cache. The applicability of this strategy to different storage technologies and the comparison with cutting-edge technologies are also illustrated. Simulation results show that the prefetching strategy can achieve at most 64.12% and 94.55% optimization effects on the miss latency and the miss rate of L3 cache, respectively.

Dynamic Response Analysis of Airport Pavement under Impact Loading

The safety of the airport runway, as an infrastructure, is of considerable concern. The existing research has problems of hysteresis and unreasonable load application. In this paper, ANSYS is used to construct a coupled tire–pavement model to study the dynamic characteristics of airport asphalt pavements under impact loading. Taking the Boeing 737–800 as an example, the impact of an aircraft landing on an airport pavement is simulated by applying a dynamic load to the landing gear. The effects of tire pressure, landing pitch angle, and sinking speed on the dynamic response of the airport runway are investigated. The effects of each factor of the airport pavement are analyzed by comparing the maximum effective stress, effective strain, and displacement in the vertical direction at the same position of different structures. The results show that when the tire pressure is 2.0 MPa, the maximum values of effective stress, effective strain, and vertical displacement increase by 29.8%, 19.1%, and 22.2%, respectively, compared with 1.0 MPa. The maximum values of effective stress, effective strain, and vertical displacement at the 3.0 m/s sinking speed increase by 25.2%, 93.1%, and 77.1%, respectively, compared with that at the sinking speed of 1 m/s, which indicates that the effect of sinking speed on the dynamic response of the pavement is more significant. However, the change in the landing pitch angle has little impact on the response parameters of the pavement. Meanwhile, the flexural tensile stress at the bottom of the surface and the equivalent effect at the top of the soil foundation must be considered in the design of the airport pavement structure.

On ways of conversion of silicon dioxide SiO2 in lithium battery systems: a review

Silicon and silicon oxide compounds SiO, SiO2, SiOx and SiOC are considered as a promising family of materials for high-energy lithium batteries due to their high theoretical capacity, widespread in nature, low cost, environmental safety and ease of synthesis. Silicon oxide compounds have replaced silicon in the hope of improving the discharge characteristics of lithium batteries. Oxides of silicon show excellent stability during cycling after structure optimization. However, they suffer from the problem of low Coulomb efficiency and high voltage hysteresis (difference in charge and discharge voltage), which prevents their practical application. Significant bulk expansion of silicon oxides during cycling and irreversible loss of capacity in the initial cycles are an obstacle to their large-scale practical use. This review pays attention to the peculiarities of the conversion of SiO2 and its hybrid compounds into the redox reaction with lithium and ways to overcome existing problems. Silicon dioxide is more resistant to bulk expansion than silicon. Various structural formats of nanometer SiO2 have been developed and tested for lithium batteries, such as nanotubes, nanorods, nanowires, nanoparticles, thin films. To solve problems in the SiO2/Li system, a number of SiO2 composites with carbon, graphene, active and inactive metals, etc. have also been proposed and studied. Analyzing the results of the studies, we found a significant role of the solid electrolyte interphase film in the efficient conversion of SiO2. In turn, the formation of a film on silicon dioxide depends on the method of synthesis of dioxide, which introduces impurities into the final synthesis product. Impurities contribute to the distortion of the solid electrolyte interphase film during the cycling of the SiO2/Li system, and the loss of discharge capacity. SiO2 dioxide obtained in a dry environment of a ball mill differs favorably from that obtained from solutions. Many efforts have been made to overcome the problems in Si-containing electrode materials, however, they have to go a certain way for large-scale practical application.

Continuous Reactor Temperature Control with Optimized PID Parameters Based on Improved Sparrow Algorithm

To address the problems of strong coupling and large hysteresis in the temperature control of a continuously stirred tank reactor (CSTR) process, an improved sparrow search algorithm (ISSA) is proposed to optimize the PID parameters. The improvement aims to solve the problems of population diversity reduction and easy-to-fall-into local optimal solutions when the traditional sparrow algorithm is close to the global optimum. This differs from other improved algorithms by adding a new Gauss Cauchy mutation strategy at the end of each iteration without increasing the time complexity of the algorithm. By introducing tent mapping in the sparrow algorithm to initialize the population, the population diversity and global search ability are improved; the golden partition coefficient is introduced in the explorer position update process to expand the search space and balance the relationship between search and exploitation; the Gauss Cauchy mutation strategy is used to enhance the ability of local minimum value search and jumping out of local optimum. Compared with the four existing classical algorithms, ISSA has improved the convergence speed, global search ability and the ability to jump out of local optimum. The proposed algorithm is combined with PID control to design an ISSA-PID temperature controller, which is simulated on a continuous reactor temperature model identified by modeling. The results show that the proposed method improves the transient and steady-state performance of the reactor temperature control with good control accuracy and robustness. Finally, the proposed algorithm is applied to a semi-physical experimental platform to verify its feasibility.

Ensemble Empirical Mode Decomposition and a Long Short-Term Memory Neural Network for Surface Water Quality Prediction of the Xiaofu River, China

Water quality prediction is an important part of water pollution prevention and control. Using a long short-term memory (LSTM) neural network to predict water quality can solve the problem that comprehensive water quality models are too complex and difficult to apply. However, as water quality time series are generally multiperiod hybrid time series, which have strongly nonlinear and nonstationary characteristics, the prediction accuracy of LSTM for water quality is not high. The ensemble empirical mode decomposition (EEMD) method can decompose the multiperiod hybrid water quality time series into several simpler single-period components. To improve the accuracy of surface water quality prediction, a water quality prediction model based on EEMD–LSTM was developed in this paper. The water quality time series was first decomposed into several intrinsic mode function components and one residual item, and then these components were used as the input of LSTM to predict water quality. The model was trained and validated using four water quality parameters (NH3-N, pH, DO, CODMn) collected from the Xiaofu River and compared with the results of a single LSTM. During the validation period, the R2 values when using LSTM for NH3-N, pH, DO and CODMn were 0.567, 0.657, 0.817 and 0.693, respectively, and the R2 values when using EEMD–LSTM for NH3-N, pH, DO and CODMn were 0.924, 0.965, 0.961 and 0.936, respectively. The results show that the developed model outperforms the single LSTM model in various evaluation indicators and greatly improves the model performance in terms of the hysteresis problem. The EEMD–LSTM model has high prediction accuracy and strong generalization ability, and further development may be valuable.

Моделирование сегнетоэлектриков на основе уравнения Фоккера-Планка и построение замкнутой системы уравнений моментов

The paper considers the modeling of uniaxial ionic ferroelectrics based on the Fokker-Planck equation. The equation is solved numerically using the stochastic analogue method. To describe the quasi-equilibrium state of a ferroelectric, a system of moments is constructed, which is closed using the Gaussian distribution and empirical dependence of critical temperature on key parameters. It is shown that the resulting system gives acceptable results on the problem of temperature hysteresis.