Compensation Control Research Articles

Model experimental studies on active heave compensation control strategy for electric-driven offshore cranes

Ship-mounted heave compensation offshore cranes are indispensable for isolating connected payloads from the support vessel during lifting operations under harsh sea conditions. In this paper, an innovative adaptive robust control strategy is presented for the electric-driven active heave compensation (EDAHC) system, combining an equivalent model predictive control (EMPC) method with a bias proportional integral derivative (BPID) framework to effectively mitigate the adverse effects of wave-induced heave motions from the support vessel on the suspended payload. Building upon the inherent field-oriented control in the permanent magnet synchronous motor (PMSM), the BPID-based control structure is introduced, motivated by its prompt responsiveness and robust resistance against model discrepancies and irregular disturbances. Facilitated by a torque compensation mechanism, the EMPC-based control scheme, synthesized with an autoregressive integrated moving average (ARIMA)-based heave motion prediction algorithm, is subsequently developed to achieve nonlinear friction deadzone correction and adaptive regulation of BPID parameters, thereby ensuring optimal performance of the EDAHC system within specified state and input constraints. Comparative experimental tests conducted on a scaled EDAHC testbed validate the superior capabilities of the proposal in station-keeping, position tracking, constraint satisfaction, and robustness against parametric uncertainties.

The research on Adaptive Fuzzy Tracking Supervisory Control in the control system of average coolant temperature of lead–bismuth-cooled reactor under multiple operating conditions in the marine environments

Lead–bismuth-cooled reactor nuclear power equipment is severely affected by marine environments, causing operational attitude changes such as heeling and rolling. Conventional controllers cannot track set points rapidly. Therefore, this paper proposes an Adaptive Fuzzy Tracking Supervisory Control method. Firstly, the reactor mathematical model based on fuzzy basis functions is obtained through fuzzy mathematics. Secondly, a coolant average temperature tracking controller is designed on Lyapunov stability theory. To ensure the system returns to stable domain, supervisory compensatory control algorithm is developed. Next, the parameters of fuzzy model are adjusted using Fuzzy universal approximation theorem. By introducing discrepancies between actual system and fuzzy model outputs, parameter adaptive law is designed through Lyapunov theorem. This enables real-time parameter adjustment for fuzzy model and fuzzy tracking supervisory controller, enhancing load tracking performance of coolant’s average temperature. Finally, simulation experiments demonstrate that adaptive fuzzy tracking supervisory controller has stronger adaptability to multiple operating conditions under marine environments.

“God is my vaccine”: the role of religion, conspiracy beliefs, and threat perception in relation to COVID-19 vaccination

AbstractReligious and conspiracy beliefs are based on the assumption that a potent force exists which is capable of affecting people’s destinies. According to compensatory control theory, the belief in such a potent external agent may serve to alleviate feelings of uncertainty and help restore a sense of control. This is of particular relevance and importance to attitudes and behaviour of religious individuals towards vaccinations during the Covid-19 pandemic, where a belief in such a potent external force controlling events and destinies may have lowered the sense of threat posed by Covid-19 and in turn reduced vaccination uptake. To test this, we conducted a cross-sectional study of highly religious adults in Poland (N = 213) and found that the number of COVID-19 vaccine doses taken was negatively predicted by conspiracy beliefs, perceived closeness to God, and frequency of church attendance, and positively predicted by the perceived COVID-19 threat. Furthermore, mediation analysis revealed that both conspiracy beliefs and perceived closeness to God were related to a decreased perception of the COVID-19 threat, which in turn led to a decreased number of vaccine doses received. Our study offers important insights for public health professionals and identifies further research pathways on conspiracy and religious beliefs in relation to health-related behaviours.

Anti-disturbance control strategy in capture stage for AUV dynamic base docking with optical guided constraints

This article investigates the challenge of potential optical guidance failure at the end of the underwater docking process due to relative attitude deviation between the Autonomous Underwater Vehicle (AUV) and the recovery platform, especially in the context of a moving base. A novel anti-disturbance control strategy is presented, accounting for environmental dynamics and optical guidance limitations. Firstly, we establish constraint models such as the effective field of view and the guidance beam associated with the optical guidance method. We then divide the recovery control strategy area based on the constraint model and propose the Line-of-sight Considering Visual Constraints (LOSCVC) docking control strategy. This strategy utilizes the line-of-sight method and the virtual leader method to make motion decisions based on the relative attitude offset and completes the docking operation by tracking the motion of the virtual leader. Furthermore, we consider the effect of ocean currents on the docking process of the moving base and design a disturbance compensation control law based on the Lyapunov redesign method. This strategy ensures the AUV maintains effective and continuous optical guidance during the capture phase, thereby achieving precise, safe, and rapid docking control. Simulation results validate the effectiveness and robustness of the proposed docking control strategy.

Research on photovoltaic grid-connected inverters with source filtering function

Abstract To suppress the current harmonics caused by the nonlinear load connected to the grid when the photovoltaic system is connected to the grid for power generation, this paper adopts a composite control strategy based on the PI-RC controller to realize the synthesis of the command current signal in different modes. According to the different command current signals, the system can work in three modes: photovoltaic grid-connected harmonic compensation control, photovoltaic grid-connected control, and harmonic compensation unified control. Under the composite control strategy, the system realizes the active output of the photovoltaic grid-connected system with the function of source filtering, compensates for the harmonics caused by nonlinear loads, successfully reduces the harmonic distortion rate of grid current, and then realizes the function expansion of photovoltaic grid-connected inverter. Finally, the feasibility and rationality of the unified control strategy designed in this study are verified by simulation experiments.

Rated flow coefficient of geometric compensation control valve

Abstract Aiming at the large design error of the rated flow coefficient of existing control valves, it was difficult to meet the requirements of the equipment system. This study adopts the principle of infinite approximation to the existing flow coefficient calculation equation for geometric shape correction compensation, based on which the rated flow coefficient design method was proposed, and simulation and test verification were carried out. The results show that according to the design method, the rated flow coefficient of the control valve can be accurately designed. The variation rule of the simulated value and the test value under the two kinds of spool inner parts is consistent, and the maximum error is not more than 10%, which meets the requirements of industrial standards. The experiment verifies the accuracy and applicability of the design method.

Development of a prototype to evaluate and monitor energy efficiency aiming at power quality 4.0

In research and development projects, the need to implement prototypes to speed up the development and delivery process is paramount, offering tools to validate scenarios and anticipate challenges. The aim of this research is to experimentally develop a prototype for monitoring electrical power systems using a gateway that converts MODBUS-RTU communication protocols to TCP, providing useful information for technicians and managers of a company in the Manaus Industrial Estate (PIM) in the field of reflective tapes. To achieve this goal, it was necessary to specify the technical requirements for panel assembly and communication via MODBUS, acquire and research materials in accordance with the technical specifications and technological requirements, implement the monitoring system with an IMS Controller for reactive power compensation, and configure and parameterise the MODBUS protocol via the RTU to TCP converter. The prototype is expected to be able to take accurate measurements and, in the data acquisition process, obtain readings of electrical quantities such as: voltage per phase; current per phase; power factor per phase; active power per phase; reactive power per phase; apparent power per phase; frequency; voltage THD and voltage harmonics. The prototype must act intelligently to drive the capacitor bank to control and monitor reactive power. The development of the prototype included crucial stages such as the specification of technical requirements, the acquisition of suitable materials, and the implementation and configuration of the system. The specification ensured that the components were aligned with the project objectives, while the procurement of materials ensured the quality and efficiency of the system. The implementation of the Automatic Reactive Power Compensation Controller was vital for reactive power compensation and the configuration of the MODBUS protocol ensured precise communication between the components. To summarise, this project demonstrates the importance of prototypes in technological advancement, offering practical and efficient solutions for industry. The prototype developed to monitor electrical power systems through a MODBUS-RTU to TCP protocol converter gateway represents a significant advance, providing essential data and contributing to informed decision-making, improving the performance and management of the company's energy resources.

Parallel adaptive RBF neural network-based active disturbance rejection control for hybrid compensation of PMSM

PurposeThis study aims to promote the anti-disturbance and tracking accuracy performance of the servo systems, in which a modified active disturbance rejection control (MADRC) scheme is proposed.Design/methodology/approachAn adaptive radial basis function (ARBF) neural network is utilized to estimate and compensate dominant friction torque disturbance, and a parallel high-gain extended state observer (PHESO) is employed to further compensate residual and other uncertain disturbances. This parallel compensation structure reduces the burden of single ESO and improves the response speed of permanent magnet synchronous motor (PMSM) to hybrid disturbances. Moreover, the sliding mode control (SMC) rate is introduced to design an adaptive update law of ARBF.FindingsSimulation and experimental results show that as compared to conventional ADRC and SMC algorithms, the position tracking error is only 2.3% and the average estimation error of the total disturbances is only 1.4% in the proposed MADRC algorithm.Originality/valueThe disturbance parallel estimation structure proposed in MADRC algorithm is proved to significantly improve the performance of anti-disturbance and tracking accuracy.

Research on gravity compensation control of BPNN upper limb rehabilitation robot based on particle swarm optimization

AbstractA four‐degree‐of‐freedom upper limb exoskeleton rehabilitation robot system with a gravity compensation device is constructed. The objective is to address the rehabilitation training needs of patients with upper limb motor dysfunction. A BP neural network adaptive control method based on particle swarm optimization is proposed. First, the degrees of freedom of the human body are analyzed, and a Lagrange method is employed to construct a dynamic model. Second, a particle swarm optimization back propagation neural network adaptive control algorithm based on particle swarm optimization is presented. Subsequently, the range of motion of the upper limbs is analyzed with reference to muscle anatomy and a three‐dimensional motion capture system. And the robot structure design is analyzed in detail. Finally, simulation experiments were conducted, and the results demonstrated that the proposed method exhibited high effectiveness and accuracy.

Is the Effect of Trust on Risk Perceptions a Matter of Knowledge, Control, and Time? An Extension and Direct-Replication Attempt of Siegrist and Cvetkovich (2000)

The complexity of societal risks such as pandemics, artificial intelligence, and climate change may lead laypeople to rely on experts and authorities when evaluating these threats. While Siegrist and Cvetkovich showed that competence-based trust in authorities correlates with perceived societal risks and benefits only when people feel unknowledgeable, recent research has yielded mixed support for this foundational work. To address this discrepancy, we conducted a direct-replication study (preregistered; 1,070 participants, 33 risks, 35,310 observations). The results contradict the original findings. However, additional non-preregistered analyses indicate an alternative perspective aligning with compensatory control theory and the description-experience framework: experiences with insufficient personal control over a threat may amplify individuals’ dependency on powerful others for risk mitigation. These findings highlight the need to reevaluate how trust shapes risk perceptions. Recent societal and technological shifts might have heightened the desire for control compared to subjective knowledge in why people resort to trust.

High-dynamic steering control of the pump-controlled electro-hydraulic steering system for heavy vehicles with active disturbance suppression

Low-frequency response, strong nonlinearity and unknown disturbances are the main challenges faced by the engineering application of the pump-controlled electro-hydraulic steering systems (EHSSs) for heavy vehicles. To solve the above problems, an active disturbance suppression controller is proposed based on a variable rate reaching law (VRRL) and a terminal sliding mode observer (TSMO) in the framework of the sliding mode control. This controller is unique because, the VRRL introduces a nonlinear activation function, which enables smooth switching between multiple reaching rates, effectively improving the response speed and the disturbance rejection performance of the pump-controlled EHSS. Furthermore, an adaptive incomplete disturbance compensation control strategy is proposed by incorporating a TSMO to further improve the accuracy and robustness of the steering system, which employs a VRRL-based TSMO to realize accurate estimation of the lumped disturbance in finite time, and avoids controller overcompensation by selecting a preferred disturbance compensation coefficient. The stability analysis demonstrates that the proposed controller effectively suppresses the lumped disturbance and reduces the convergence domain of the steering system. A pump-controlled EHSS experimental bench is constructed, and a series of experiments are conducted with various steering frequencies and load conditions, which validate the ability of the proposed controller to achieve high-precision dynamic steering in all-terrain conditions of the pump-controlled EHSS for heavy vehicles.

A quasi-harmonic voltage compensation control of current-controlled battery energy storage systems for suppressing mid-frequency oscillations and harmonics

In grid-connected mode, current-controlled battery energy storage systems (BESS) face the issues of harmonic caused by nonlinear loads and interactive instability under weak grids. Firstly, the mechanisms of mid-frequency oscillations (MFO) and mid-frequency harmonics (MFH) are revealed by the impedance network theory and the circuit principle. Because harmonic currents of nonlinear loads tend to interact with the mid-frequency impedance of BESS to produce harmonic voltage drops, the grid is susceptible to MFH. Worse still, the grid-connected system based on BESS tends to exhibit negative damping characteristics in the mid-frequency band as the grid stiffness decreases, which triggers MFO. Aiming at the above problems, this paper proposes a quasi-harmonic voltage compensation control strategy without any harmonic extractor and provides a detailed parameter design rule. The proposed control strategy can effectively suppress MFO by enhancing the damping between BESS and weak grids. Meanwhile, the disturbance resistance of BESS to nonlinear loads is significantly improved because the impedance magnitude of BESS in the mid-frequency band is obviously reduced. Finally, the effectiveness of the proposed strategy is verified by simulation and experiment.

Contour error control for the biaxial system based on active disturbance rejection generalised prediction

ABSTRACT For the purpose of contour error control in two-axis systems, a cross-coupled controller utilising auto-disturbance rejection generalised predictive control and nonlinear proportional differentiation is proposed. The contour error components along each axis are estimated by utilising the information from the nearest reference point and its adjacent reference points. The combination of ADRC and GPC is utilised for uniaxial tracking control. The LESO is utilised for estimating and compensating for the total disturbance of the system while simplifying it into two cascaded integrators. Because GPC is designed only for the series form of the integrator, the dependence on mathematical models is reduced. A nonlinear cross-coupled controller is designed utilising the fal function, with compensation control quantities for each axis directly obtained from their respective contour error components. Finally, the results obtained from the simulation demonstrate that the control strategy can availably enhance the performance of single-axis tracking and contour processing.

Precise pose control of shaft boring machine considering the characteristic of stratum

The shaft boring machine (SBM) is innovatively applied to shaft engineering with depth and large diameter for the advantages of efficiency, adaptability, and safety. The manual and rough pose control of SBM blocks the improvement of engineering quality and efficiency. This article presents a precise pose control method for SBM considering the characteristics of strata. The kinematic model of SBM and the mechanical-hydraulic-rock coupled dynamic model of grippers actuator are established considering the characteristics of different surrounding rock, respectively. A test rig is established to validate these models. The stratum-adapted double-layer controller is designed for the pose control from the practical aspects, including the deviation and inclination of the SBM center. The upper layer devotes to the kinematic planning between pose and displacement of grippers. The linear active disturbance rejection control (LADRC) method is used to control each gripper in the lower layer. The compensation control strategy is proposed to improve the reliability of the system under the different strata conditions. The stratum-adapted property is validated with the simulation of different surrounding rock characteristics. The control test under hard rock condition is performed with the test rig. The results indicate that the displacement control error of the single gripper cylinder is less than 1.8%, and the corresponding control error of deviation and inclination angle of the SBM center is less than 2.1% and 2.3% respectively. The proposed method can cover the precise pose control under different strata conditions, and it can be applied in the shaft infrastructure construction practically.

Finite-time compensation control with dead-zone estimation for a rehabilitative walker considering internal disturbance forces

This study discusses a finite-time compensation tracking control method for a rehabilitative training walker. The dynamic model with input dead zone was constructed to describe the walker, and a finite-time disturbance forces observation method was proposed based on the impact mechanism on tracking performance. This approach is novel in that the disturbance forces were observed in reverse through their effects on tracking performance, thus successfully obtaining the disturbance forces of the walker. To ensure the practical finite-time stability of the system, the nonlinear finite-time compensation tracking controller with stochastic configuration networks (SCN) dead-zone estimation was built for the rehabilitative walker. Simulation results and comparative analyses confirmed that the proposed compensation control method effectively restrains dead zone and internal disturbance forces.

The Design and Implementation of a Wide-band Circularly Polarized Conformal Antenna

Background: It gives out the design and verification of single-layer dual-band antenna unit and multi-layer dual-band broadband antenna unit of phased array antenna, and verifies that the multi-layer dual-band broadband antenna unit can meet the design requirements of the receiving frequency band. Objective: It gives out the design and implementation of a wide-band circularly polarized conformal antenna, and presents the characteristics analysis of the antenna. Method: Through related simulation methods, the proposed methods are verified and they can effectively solve the array phase compensation and beam shaping and control in the wide-band circularly polarized conformal antenna. Results: Based on the basic design of the antenna, the active superposition algorithm, phase compensation technology and particle swarm optimization antenna beam shaping technology are both studied. Conclusion: The proposed wide-band circularly polarized conformal antenna can be used in the actual application.

Polynomial Excitation Current Compensation Control for Dead Zone and Hysteresis of Three-way Proportional Pressure Reducing Valve

Polynomial Excitation Current Compensation Control for Dead Zone and Hysteresis of Three-way Proportional Pressure Reducing Valve

Sliding Mode Speed Control for PMSM Based on Model Predictive Current

To enhance the dynamic performance and disturbance rejection capability of the permanent magnet synchronous motor speed control system, a novel speed control method based on a novel sliding mode control (NSMC) and load torque observer is proposed on the basis of model predictive current control (MPCC) with a sliding mode disturbance observer. First, on the basis of MPCC, the influence of parameters such as resistance, inductance, and flux linkage on MPCC is analyzed. To address the aggregated disturbance caused by parameter mismatches, a piecewise square-root switching function sliding mode disturbance observer (SMDO) is designed to enhance the robustness of the parameters. To address the poor dynamic performance and inadequate robustness resulting from the proportional-integral-controller (PI) velocity loop control in the MPCC, a novel NSMC velocity control method is proposed. This method utilizes the hyperbolic sine function and fractional-order integral sliding mode surface, resolving the dilemma faced by traditional slide mode controllers (SMC) in balancing fast response and reduced vibration. Additionally, to enhance the system’s disturbance rejection capability, a sliding mode torque observer (SMTO) is designed to continuously update the observed load torque value into the NSMC controller, achieving speed compensation control. Finally, through comparative experiments among the proportional integral controller (PI), SMC, NSMC, and NSMC + SMTO, the results indicate that the proposed NSMC + SMTO exhibits the best speed response, steady-state characteristics, and disturbance rejection capability.

An advanced integral sliding mode controller design for residual current compensation inverters in compensated power networks to mitigate powerline bushfire hazards

AbstractThis work deals with designing an advanced integral sliding mode controller (AISMC) for residual current compensation (RCC) inverters connected with arc suppression coils to compensate for power distribution networks where the main idea is to alleviate hazardous circumstances caused by electric faults on powerlines. The key advancement in the proposed AISMC over traditional sliding mode controllers is the utilization of an improved exponential reaching law which ensures the faster convergence of the desired control objective that is the fault current compensation in this particular application. An improved exponential reaching law (IERL) used in this work is a combination of the exponential and constant‐proportional reaching laws (while existing approaches use constant reaching laws) which assists to minimize the current injection error through the RCC inverter in the steady‐state. The integral action in conjunction with the exponential function in the sliding surface, based on which the proposed controller is designed, helps to eliminate the chattering effects in a quickest way that can be evidenced from the settling time and percentage overshoot. The feasibility of the proposed AISMC is theoretically assessed by analyzing the stability using the Lyapunov stability theory. Simulation and processor‐in‐loop results further justify the theoretical foundation by confirming the desired current injection and compensating voltage and current due to the fault. Finally, results are compared with a TIMSC for demonstrating the superiority of the AISMC.

An improved dynamic Prandtl–Ishlinskii hysteresis model and a PID-type adaptive sliding mode controller for piezoelectric micro-motion platform

Piezoelectric actuators are widely used in the field of micro-nano driving due to their advantages of fast frequency response, high displacement resolution, large stiffness, small size, and low heat generation. However, the hysteresis non-linearity of piezoelectric actuators severely affects their positioning accuracy during operation. Therefore, the study of hysteresis model and compensation control for piezoelectric actuators has always been a hot topic in the field of micro-nano driving. However, existing hysteresis models and control methods cannot well describe the dynamic hysteresis curve of piezoelectric actuators and track the desired trajectory. To address this issue, this paper proposes an improved dynamic Prandtl–Ishlinskii (IDPI) model and a finite-time trajectory tracking adaptive sliding mode control method based on PID-type. Firstly, this paper introduces the construction and parameter identification method of the IDPI model. Secondly, the accuracy of the IDPI model in describing hysteresis curves under different input signals is verified through experiments, and the effectiveness of the feedforward controller based on the IDPI model is validated experimentally. Then, considering the modeling uncertainty, unmodeled internal dynamics, and external environmental disturbances of the piezoelectric micro-motion platform, a finite-time trajectory tracking adaptive sliding mode controller based on PID-type is designed to suppress the non-linear characteristics of the piezoelectric micro-motion platform. Finally, the performance of the compensator is verified through simulation experiments.