Compensation Characteristics Research Articles

Improved sliding mode dynamic matrix control strategy: Application on spindle loading and precision measuring device based on piezoelectric actuator

Spindle workload simulation and precision measurement are important in evaluating the precision of the spindle under different working conditions. Controlling the loading and measuring system accurately is difficult due to the robustness requirements of the controller, the complex dynamic model of the spindle loading system, the difficulty of obtaining system parameters, and the hysteresis of the piezoelectric actuator (PEA). To overcome this challenge, this study refers to the dynamic matrix control (DMC) method and proposes a highly versatile, robust, improved sliding mode DMC predictive controller (ISLDMC). ISLDMC is a non-inverse model control method with strong stickiness and good tracking characteristics. To help the controller achieve good versatility, this study regards nonlinear links, such as hysteresis of PEA, as an unknown disturbance and collects the step response signals of the piezoelectric system as the model state equation. In consideration of the practical application of the piezoelectric system, the prediction function of the state equation is used at the feedforward end of the controller, and the sliding mode function and incremental output are unified at the output end via weighted form optimization. In the feedback part, a variable correction coefficient is introduced into the state equation of the controller to enhance the tracking characteristics of the controller. This improvement is independently verified in a simulation environment. The design method of the controller is provided, the Schur stability of the closed-loop control system is proven. Moreover, the proposed controller is applied to machine tool spindle workload simulation and a precision-measuring device based on piezoelectric actuators. ISLDMC-based displacement-tracking and force-tracking controllers are designed. The experiment showed that the tracking performance and anti-interference, anti-model mismatch, and linear compensation capabilities of ISLDMC are better than those of the DMC controller, PI controller, and controllers from other studies. Furthermore, the linear compensation and anti-disturbance characteristics of the ISLDMC controller with the step response as the state equation are verified through force tracking experiments, which reveal that ISLDMC has good force tracking performance and anti-disturbance and linear compensation characteristics. The effectiveness of the introduction of dynamic correction coefficients is verified through a separate simulation involving displacement tracking and piezoelectric load experiments. The findings confirm that compared with the DMC controller, the ISLDMC controller improves tracking characteristics to a certain extent and has higher robustness.

Research on back- pressure compensation characteristics of a pilot-assisted load control valve applied in overrunning load hydraulic systems

This paper reports the research of proportion flow control with back-pressure compensation feature on an LCV (load control valve). The back-pressure compensation feature means when back-pressure rises, flow of the LCV can be unchanged or lower. The back-pressure compensation feature is very important to the safety of the system, because high back-pressure will make the main valve open larger and lowering speed be undesired faster. In this paper, static equilibrium equations of LCV were established and influence relationship of back-pressure and other parameters was derived. In addition, back-pressure influence was simulated, based on above analysis a preliminary optimization scheme was proposed and tested. After that, the method of back-pressure compensation was proposed and has been verified by simulation. Finally, an LCV with back-pressure compensation feature was tested on the test rig. Experiment data validates that the main flow of the LCV with back-pressure compensation method was lower under a higher back-pressure and the pilot pressure control region was unchanged.

Research on dynamic characteristics of pressure compensator for deep-sea hydraulic system

The pressure compensator is an important equipment of the deep-sea hydraulic system to provide the functions of pressure and volume compensation. In this paper, the structure features and static force analysis of the pressure compensator are studied. The physical model of the pressure compensator is established, and its dynamic characteristics influenced by the ambient pressure, the compensated flow and the temperature change are all analyzed. The entire working process of the pressure compensator is then researched. Therefore, two design criteria for reliability and dynamic characteristics respectively are proposed. A pressure compensator for 6000 m deep in the sea was designed and manufactured. Simulations and high-pressure experiments of the designed pressure compensator were conducted. The results show that the dynamic response of the compensated pressure under each input is all composed of a ramp change, a step change and a damped oscillation. The effective area of the rolling diaphragm, the spring stiffness and the mass of the diaphragm-piston assembly are the key design parameters to ensure the reliability and good dynamic characteristics of the pressure compensator. Simulation and high-pressure experiments verified the volume and pressure compensation function of the pressure compensator in the deep-sea environment.

An augmented food strategy leads to complete energy compensation during a 15-day military training expedition in the cold.

Soldiers on military expeditions usually fail to compensate for the increase in energy expenditure, with potential deleterious consequences. We therefore analyzed the characteristics of energy compensation in 12 male soldiers, during a 15‐day expedition in the cold, while alleviating some of the contextual limitations of food intake (~20‐MJ daily bags of easy‐to‐use, highly palatable and familiar foods with multiple and long breaks allowed during the day). Body and fat mass losses were low and moderate, respectively (−1.13 ± 1.42% and −19.5 ± 15.6%, respectively, p < .021). Mean energy intake (EI) was high (~16.3 MJ) and increased at each third of the expedition (15.3 ± 2.1, 16.1 ± 2.1, and 17.6 ± 2.0 for D1–5, D6–10 and D11–15, respectively, p < .012). This resulted in reaching a neutral energy balance as soon as the D6 to 10 period and reaching normal energy availability during D11 to 15. Participants only increased their EI during the mid‐day (10:00–14:00) period (p = .002) whereas hunger and thirst only increased in the morning, with higher scores during D11–15 than D1–5 (p < .009). Last, the reward value of sweet foods was also higher during D11–15 than during D1–5 (p = .026). The changes in body mass were positively associated with EI (r = 0.598, p = .040) and carbohydrate intake (r = 0.622, p = .031). This study indicates that complete energy compensation can be reached in challenging field conditions when food intake is facilitated, offering some guidelines to limit energy deficit during operational missions.

Improvement of Voice Quality using a Digital Filter to Compensate for the Spatial Characteristics of MEMS Microphone Chambers

Micro-electromechanical system (MEMS) microphones are sound sensors that are widely used in modern mobile and Internet-of-Things devices. Their market share is rapidly increasing due to their small size, excellent performance characteristics, and low power consumption. However, studies have focused on improving module performance without any spatial considerations. Most voice recognition devices have a small internal chamber in which a sensor is installed. A chamber with an open hole serves as a resonator, which alters the MEMS microphone’s characteristics. The aim of this study is to improve voice quality by using a digital filter to compensate for the effect of the chamber. This will allow the identification of frequency-response compensation characteristics and the acquisition of base data that can be used for product design.

Phase Compensation Method in OPA System Based on the Linear Electro-Optic Effect

Factors such as mechanical deformation and temperature changes lead to phase mismatch in optical parametric amplification systems, impacting energy stability. A phase compensation method via the linear electro-optic effect can overcome this limitation. Phase mismatch compensation characteristics were simulated via the linear electro-optic effect in 70%-deuterated DKDP and 95%-deuterated DKDP. This method was applied to OPA systems to verify its feasibility. The results show that the temperature acceptance bandwidth of 70%-deuterated DKDP and 95%-deuterated DKDP can be ~1.75 and ~2 times larger, respectively, than that of the OPA without compensation. Moreover, the angle acceptance bandwidth of 70%-deuterated DKDP and 95%-deuterated DKDP can be ~2 times larger than that of the OPA without compensation. The abovementioned method can facilitate the compensation of phase mismatch within a range and can be widely used in OPA and optical parametric chirped pulse amplification systems to improve laser stability.

Range Ambiguous Clutter Suppression for FDA-MIMO Forward Looking Airborne Radar Based on Main Lobe Correction

Generally ground clutter has serious range dependence and range ambiguity in the forward-looking array airborne radar system under a high pulse repetition frequency (PRF) system. In this work, a range ambiguous clutter suppression method based on transmitting beam main lobe correction for the FDA MIMO radar is proposed. Firstly, this method uses the designed transmission pulse weights to compensate for the initial phases formed by the accumulation of frequency increments between pulses, so as to solve the problem that the main lobe high gain illuminated angle is inconsistent between the MIMO equivalent transmitting beampattern pulses synthesized at the receiving in the traditional FDA MIMO system. Secondly, by restoring and compensating received echoes, the influence of the main lobe correction weights of the transmitting signal is eliminated. Finally, through the characteristics of transmitter correction compensation to distinguish different range ambiguous clutters, the echoes from the range ambiguous areas can be discretely distributed in the power spectrum while preserving the signal echoes in the observation area. Thus range ambiguous clutter suppression is realized. The simulation results show that the proposed method can improve the clutter suppression performance compared with the MIMO and linear frequency increment FDA radar.

Joint Functional Focus of Models of Civil Liability for Damage Inflicted on Patients

One of the key areas of legal regulation of any aspect of public life (especially when it comes to personal moral rights inalienable from a person, including those that ensure the person's physical existence and reflect the human dignity inherent in every individual) is the establishment of legal guarantees for the observance and protection of subjective rights belonging to a person. The purpose of this study is to determine the centripetal (in value and functional terms) trends in the development and application of similar legal models and means of legal regulation of relations arising from harm inflicted on patients. It was concluded on the inevitability of the intensification of the world, and European, in particular, tendencies regarding the diverse use by national legal systems of similar functional legal instruments for compensation for property and moral damage in order to ensure effective protection of personal non-property and property rights of patients and related persons. Therewith, the identity of a certain national legal mechanism will be determined mainly by the orientation of the legal policy of a particular state towards the top-priority implementation of certain characteristics of compensation and proactive, preventive (which, in the context under consideration, appears as a guarantee for the observance of the rights of patients and the performance of obligations by the providers of medical services) functions of civil liability.

Modeling and Efficiency Analysis of LCC-S Inductive Power Transmission (IPT) system

This paper analyzed the factors affecting the transmission efficiency of IPT system based on LCC-S compensation topology. By modeling LCC-S compensation networks, the condition of input impedance as resistive load is derived and the frequency characteristics of input impedance have been analyzed. And the frequency working range to improve the efficiency of the system have been also derived. The input and output characteristics of LCC-S compensation are further studied, and the effect of parameters on regulating the transmission power of IPT system have been verified, which provide an idea for the parameter design of IPT system compensation network.

Metformin Preserves β-Cell Compensation in Insulin Secretion and Mass Expansion in Prediabetic Nile Rats.

Prediabetes is a high-risk condition for type 2 diabetes (T2D). Pancreatic β-cells adapt to impaired glucose regulation in prediabetes by increasing insulin secretion and β-cell mass expansion. In people with prediabetes, metformin has been shown to prevent prediabetes conversion to diabetes. However, emerging evidence indicates that metformin has negative effects on β-cell function and survival. Our previous study established the Nile rat (NR) as a model for prediabetes, recapitulating characteristics of human β-cell compensation in function and mass expansion. In this study, we investigated the action of metformin on β-cells in vivo and in vitro. A 7-week metformin treatment improved glucose tolerance by reducing hepatic glucose output and enhancing insulin secretion. Although high-dose metformin inhibited β-cell glucose-stimulated insulin secretion in vitro, stimulation of β-cell insulin secretion was preserved in metformin-treated NRs via an indirect mechanism. Moreover, β-cells in NRs receiving metformin exhibited increased endoplasmic reticulum (ER) chaperones and alleviated apoptotic unfold protein response (UPR) without changes in the expression of cell identity genes. Additionally, metformin did not suppress β-cell mass compensation or proliferation. Taken together, despite the conflicting role indicated by in vitro studies, administration of metformin does not exert a negative effect on β-cell function or cell mass and, instead, early metformin treatment may help protect β-cells from exhaustion and decompensation.

Evaluation of Position Controllability of Triaxial Active Control Magnetic Bearing Using Nonlinear Compensator

Magnetic bearings (MBs) levitate and suspend rotors. MBs have some advantages such as low friction, no wear, and no risk of fluid pollution because they can suspend rotors without mechanical contacts and lubricants. To avoid increasing the size of systems, triaxial active control magnetic bearings (triaxial AMBs) have been proposed. We proposed the triaxial AMB without permanent magnets which has an asymmetric structure. It is specially designed for high-temperature turbomachines. However, the triaxial AMB has interference characteris-tics when it suspends a rotor in the radial and thrust direction simultaneously. In order to solve this problem, the position control system with a non-linear compensator is proposed. The compensation characteristics are changed by current and rotor displacement. It is proved that the compensator can suppress the interference. However, it is not clarified how the position controllability changes when the compensation characteristics change. We investigate the position controllability when the compensator has different characteristics.

Ultrathin Three-Axis FBG Wrist Force Sensor for Collaborative Robots

Collaborative robots equipped with multicomponent force-sensing systems at the human-robot-environment interaction interface provides competitive advantages, such as collaboration, flexibility, and reliability. Most wrist force sensors use the cross-beam structures with electrical strain gauge measurement technologies. This article proposes an approach to develop a new ultrathin three-axis fiber Bragg grating (FBG) force sensor. First, an appropriate elastomer with embedded floating beams in ultrathin dimensions to measure three-axis force is designed using a finite-element method (FEM). A temperature-compensated extreme learning machine (TC-ELM) network is proposed to achieve the characteristics of low coupling and temperature compensation (TC). Calibration and experiment on the UR5 robot are conducted, and results illustrate that the highest sensitivity of the sensor can reach 34.07 pm/N, the repetition error is less than 5%, and the maximum coupling error is less than 0.21%. The maximum temperature drift after compensation is less than 20 pm. The proposed sensor has identical output as a commercial sensor and performs well in dynamic loading and unloading operations. Finally, comparison results from commercial and academic alternatives demonstrate the interest of the proposed approach to develop high-performance and integrated force-sensing solutions.

MATLAB Simulation Research on Static Var Compensator

TCR-TSC static reactive power compensator (SVC) is the most widely used in the field of power system reactive power compensation. This type of reactive power compensator can not only compensate the reactive power required in the power system, but also handle the over-compensation problem well. This paper will establish a MATLAB simulation model to simulate the TCR-TSC SVC, focusing on the dynamic reactive power compensation characteristics of the TCR-TSC SVC in suppressing voltage fluctuations. The simulation results show that the TCR-TSC SVC has a better dynamic reactive power compensation effect.

Study on Operation Parameter Characteristics of Induction Filter Distribution Transformer in Low-Voltage Distribution Network

There is a need for induction filter technology in the field of low-voltage distribution networks. This paper proposes an induction filter distribution transformer with a unique Dd0yn11 three-winding configuration. This approach allows for the control of load side harmonics in low-voltage distribution networks. At present, the induction filter technology proposed in the known literature is mostly used in the high-voltage power system, but there is still no research on the application of induction filter technology to the distribution transformer with Dyn11 under the low-voltage distribution network. In this paper, the wiring scheme of inductive filter distribution transformer and filter system in low-voltage distribution network is established firstly, then the mathematical relationship between the harmonic current generated by the load side and the current on the grid side is derived according to the winding model, and it can be deduced that the induction filter distribution transformer with its filtering system has good filtering performance and reactive power compensation characteristics. Finally, the experiment simulates the three-phase harmonic load, detects the current waveform and other parameters of the actual grid side of the new transformer, verifies the correctness of the theoretical analysis. The induction filter distribution transformer proposed in this paper provides a new solution for harmonic suppression and reactive power compensation in low-voltage distribution network, which fills the vacancy of the application of induction filter technology in low-voltage distribution network, This paper reveals that the inductive filter technique has a good filtering performance when applied to low-voltage distribution network. And it provides a reference for further research on improving power grid efficiency, saving energy cost and improving transformer electromagnetic environment under low-voltage distribution network.

An R-L Static Var Compensator (SVC)

Traditional static var compensators (SVCs) employ shunt reactors and capacitors. These standard reactive power shunt elements are controlled to produce rapid and variable reactive power. Power electronic devices like the thyristor etc. are used to switch them in or out of the network to which they are connected in response to system conditions. There are two basic types, namely the thyristor-controlled reactor (TCR), and the thyristor-switched capacitor (TSC). In this paper we wish to investigate a compensator where the reactor or capacitor is replaced by a series connected resistor and reactor (R-L). The performance equations are derived and applied to produce the compensator characteristics for each of the configurations. Their performances are compared, and the contrasts between them displayed. All three configurations are made to achieve unity power factor in a system.

An R-L Static Var Compensator (SVC)

Traditional static var compensators (SVCs) employ shunt reactors and capacitors. These standard reactive power shunt elements are controlled to produce rapid and variable reactive power. Power electronic devices like the thyristor etc. are used to switch them in or out of the network to which they are connected in response to system conditions. There are two basic types, namely the thyristor-controlled reactor (TCR), and the thyristor-switched capacitor (TSC). In this paper we wish to investigate a compensator where the reactor or capacitor is replaced by a series connected resistor and reactor (R-L). The performance equations are derived and applied to produce the compensator characteristics for each of the configurations. Their performances are compared, and the contrasts between them displayed. All three configurations are made to achieve unity power factor in a system.

Research on the simulation of a new compensation strategy for dynamic voltage correction device

A new detection and compensation method for voltage sag is proposed. Dynamic voltage correction device(DVCD) is the most effective device to solve voltage sag. Based on the shortcomings of the traditional compensation strategy, the compensation characteristics of the compensation strategy are analyzed systematically. This paper proposes a new compensation method based on the traditional minimum energy compensation method, which uses different minimum energy methods for different sags, namely zero active power exchange and minimum energy exchange. Through Simulink to establish the simulation model of minimum energy method, and make simulation analysis. The simulation results show that the method can achieve the minimum output active power while ensuring the compensation effect, which proves the feasibility and effectiveness of the method. This method can make full use of energy storage of equipment and has high economic benefits.

Characteristics of Reactive Power Compensation for Islanded Microgrids Based on Synchronized Current Phasor Control

Synchronized Current Phasor Control (SCPC) is a new control method proposed recently for islanded microgrids. This paper firstly investigates the reactive power compensation characteristics of the SCPC islanded microgrid with I-V droop control, then analyzes the influence of the droop coefficient on it. Through this study, we find that the traditional reactive power compensation strategies are no longer adapted to SCPC islanded microgrids, since their characteristics of reactive power compensation are different from the traditional grid or other islanded microgrids controlled by the typical methods.

Single-Line-to-Ground Fault Feeder Selection Considering Device Polarity Reverse Installation in Resonant Grounding System

This paper proposes a new method to select single-line-to-ground (SLG) fault feeder in resonant grounding power distribution system based on compensation characteristic of extinction coil in different frequencies. The proposed method is insusceptible to the influence of device polarity reverse installation. Firstly, through analyzing the zero sequence equivalent circuit under a SLG fault, the difference of zero sequence current share in fundamental frequency and second-harmonic frequency is investigated. And then, according to the change of current share (CCS), fault feeder selection criterion and steps are established. Finally, numerous simulation tests demonstrate the effectiveness of the proposed method in identifying the faulty feeder or the faulty bus. Besides, its reliability is also verified by tests with different system parameters and different fault conditions. Specially, device polarity reverse installation tests and comparisons are also implemented, which shows the advantages of the proposed method in dealing with device polarity reverse installation.

The multi-objective optimal allocation method of static var compensator based on transient voltage security control

Based on the detailed consideration of the dynamic characteristics of Static Var Compensator (SVC), the mathematical method for installing location and optimal capacity of SVC considering transient voltage security is proposed. Firstly, the trajectory sensitivity index is used to determine the key fault set and SVC candidate location. Then, transient voltage security constraint of the bus voltage is restored to 0.75pu within 1s and the bus voltage is restored to 0.9pu within 3s after remove fault, Finally, considering the transient voltage recovery characteristics and dynamic characteristics of SVC, the minimum of bus voltage deviation after fault removed and minimum of installtion capacity of SVC as objective function for hybrid optimal allocation model. The bus voltage and capacity of SVC are introduced as variables into the Crisscross Optimization Algorithm (CSO) for solving. The effectiveness of the proposed SVC installation location and capacity optimization method is verified by the time domain simulation of the IEEE39-bus system.