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Gimbal systems serve as critical mechanisms for carrying payloads and accurately aligning them with specific lines of sight. Designing controllers for these gimbal systems necessitates robustness against external disturbances and variations in system parameters. Various control methods have been explored in existing literature to address this challenge. In the scope of this study, we investigate the performance of four distinct control strategies—Proportional-Integral (PI) control, Self-Tuning PI control, Integral Action LinearQuadratic regulator (IA-LQR), and Relay Sliding Mode Control based on the Input-Output Model (RSMCIO)—as speed controllers for a gimbal system. We assess their efficacy through both simulation-based experiments and real-world applications, offering a comprehensive analysis of their outcomes. Beyond speed control, we extend our investigation to include cascade position control, employing a ProportionalDerivative (PD) control structure in the outer loop. Our study focuses on evaluating the performance of these diverse control structures when subjected to disturbances and variations in model parameters. To the best of our knowledge, this research marks the first attempt to apply the RSMC-IO approach to gimbal systems, enhancing our understanding of control strategies in this context and offering valuable insights into their practical implications. [ABSTRACT FROM AUTHOR]

According to the operating modes of three‐phase line‐voltage cascaded boost high power factor rectifier topology, the operating characteristics of the rectified output voltage of each module and the characteristics of the topology for automatically balancing the input current under the unbalanced grid are analyzed in this article. Based on the analysis to the unique feature, a simple dual‐loop PI control strategy in the rotating coordinate system is designed with no need to deal with the negative sequence component of grid voltage. In response to the issue of unbalanced DC‐link capacitor voltage of each module caused by unbalanced grid, injection of the zero‐sequence voltage component is adopted in the designed control system, which make the output power of each module be able to be independently regulated, so that the balancing control to the DC‐link capacitor voltage of each module is realized. At the same time, the three‐phase input currents always remain in balance automatically operating under unity power factor. Simulations and experiments have verified the superiority of the topology structure and the feasibility of the control strategy. [ABSTRACT FROM AUTHOR]

This paper presents challenges in the control of 5GDHC networks and proposes an approach for the robust control design of these networks. Temperatures are low and temperature differences are small in 5GDHC networks, in order to minimise heat losses in the distribution network and directly utilise low-temperature heat sources. Therefore, the robust control design of substations is crucial for stable and efficient operation of 5GDHC networks. We proposed the key steps to obtain a consistent control design that can be verified and tested prior to commissioning of the building substations and network. The design approach was elaborated in a case study in an existing neighbourhood in Haarlem, the Netherlands, constructed in the 1930s to 1970s. This neighbourhood will become independent of natural gas using PVT-rooftop panels, individual heat pumps (HP), a 2-pipe, bi-directional energy flow network operating at ultra-low temperatures and ATES system as a seasonal and daily storage facility. [ABSTRACT FROM AUTHOR]

Field-Oriented Control (FOC) is widely recognized as a standard framework for Permanent Magnet Synchronous Motor (PMSM) drives. Linear control techniques are commonly employed in designing controllers for this strategy. However, traditional control methods often exhibit performance limitations and reduced robustness, particularly under harsh operating conditions, which makes the FOC structure less appealing and less effective. To address and overcome these challenges, this study proposes a Second-order Non-singular Terminal Sliding (SNTS) mode approach to achieve fast, accurate, and robust tracking for the FOC control structure applied to PMSM drives. The SNTS method combines the benefits of nonsingular terminal sliding mode and second-order control laws. This approach ensures rapid and precise tracking while minimizing steady-state errors by using a nonlinear terminal sliding mode surface instead of a linear one. Furthermore, the system state transitions smoothly along the sliding mode surface with continuous functions, which reduces chattering around the sliding surface. The second-order control law incorporated into this method helps mitigate chattering and achieve fast convergence. The Lyapunov stability theory is employed to verify the stability of the SNTS technique designed for the PMSM system. Simulation and experimental validation on a hardware platform confirm the effectiveness and superiority of the proposed SNTS method, demonstrating its capability to enhance the performance of speed controllers for PMSM drives. [ABSTRACT FROM AUTHOR]

Abstract This article presents an intelligent stability monitoring and improvement method for the grid‐connected converter system. The model of grid‐connected converter, based on the weighted average current feedback (WACF) and weighted average voltage feedforward (WAVF) control, is first established. Then, the time‐varying grid impedance and parameter perturbation of LCL‐filter are precisely identified by artificial neural network (ANN) module in real time. Furthermore, the control parameters are adaptively tuned by certain rules based on the predicted parameters to increase the high‐frequency stability margin of converter system. Simulation and experimental results are given to validate the proposed identification and parameter tuning method. The proposed method is able to monitor the real‐time operation state of the grid‐connected converter and improve the self‐adaptivity of the grid‐connected converter system against parameter perturbation.

Abstract Given the presence of various non‐ideal conditions, such as detection errors, converter non‐linearity, noise, and parameter mismatches, the flux model experiences the introduction of DC bias and high‐frequency harmonics, which subsequently deteriorate the accuracy of flux estimation. To dispose these issues, an improved non‐linear flux observer (FOIFFO) using a second‐order generalised integrator as an in‐loop filter is proposed for the sensorless control of permanent magnet synchronous motors. The observer demonstrates robust performance in eliminating DC bias and having a strong filtering ability for high‐order harmonics even without amplitude and phase compensation to accurately estimate the rotational speed and rotor position. The performance of the method is analysed by transfer functions and bode plots, while the discretisation method of the FOIFFO is proposed. Finally, the new sensorless control strategy is verified by synthesising the experimental results.

Abstract The multivariable process plays a significant role in industrial applications, and designing a controller for the Multi-Input Multi-Output process is challenging due to dynamic process changes and interactions between system variables. Traditionally, the PI family of controllers has been used for its simple design, easy tuning, and quick deployment. However, these processes require complex control actions due to multiple loops in process plants. Thus, this paper proposes an Iterative Learning Controller Dead-time compensating PI, which utilizes the newly developed hybrid Simulated Annealing-Ant Lion Optimization algorithm for Single-Input Single-Output process simulation and real-time experimentation on the Quadruple Tank System. To validate the effectiveness of the developed controller, Machine Learning techniques such as regression and ensemble trees are used to accurately predict the actual system response using error values from respective processes. The simulation and experimental results demonstrate that the proposed controller achieved better performance. The regression and ensemble tree algorithm models effectively predicted the actual response. The obtained data shows that the proposed controller improved system stability and robustness by minimizing nearly half of the overshoot and improving settling time, with an average of 29.9596% faster than the other controller in the SISO process and 14.6116% in the MIMO process.

Abstract A vast number of mass flow controllers (MFCs) are used in semiconductor industry. For the stable supply, an efficient production method of MFC is required. The gain tuning of the proportional-integral (PI) control to realize a setting flow rate is essential for efficient mass production. The gains are tuned to meet the specifications required for evaluation indices of response time and overshoot amount in a step response waveform. The tuning is complicated especially for the case of pressure-based MFCs. In this paper, we propose a simple method for the PI gain tuning using the Gaussian mixture model (GMM) and the direct inverse analysis applicable to the pressure-based MFCs’ production. The relationship between the gains and evaluation indices for a standard unit of the MFC is modeled as the GMM. The direct inverse analysis calculates the difference between the standard and a test unit. Under the assumption that the difference can be compensated by a simple shift, gains likely to meet the specifications for the test unit are searched. We applied the method to seven test units. The result showed that the gains of all the test units were tuned within only a few iterations whose numbers were much less than the conventional manual tuning method, and there was no untunable unit.

Abstract This paper proposes an improved two‐degree‐of‐freedom active disturbance rejection controller for the coupling problem of asynchronous motor vector system. To simplify the analysis process and accommodate observers of different types, a unified expression based on different controllers for the system output is developed. The closed‐loop transfer function generated by the reference input and load disturbance is given. For the coupling problem of motor output speed and immunity, the structure of a higher‐order extended state observer is reconstructed. The extended state observer estimates both the output speed and the total system disturbance, which serve as feedback and feed‐forward compensation quantities. Compared to the PI controller and traditional active disturbance rejection controller, the proposed controller achieves decoupling of output response speed and immunity, simplifies the process of parameter tuning. Finally, simulation and experiment results verify the feasibility and effectiveness of the algorithm in this paper.

The linear power amplifier (LPA) suffers from low power supply utilization in the DC power supply mode, leading to reduced output efficiency. This paper constructs an efficient power supply mode based on closed‐loop dynamic power supply system (CLDPSs). The CLDPSs can generate a pair of bipolar dynamic power supplies based on a predetermined signal to provide power to LPA, which can maintain a small voltage drop between the power supply and the output of LPA, thereby improving the power supply utilization of LPA. In addition, the study also focuses on the conflicting relationship between the output ripple and the dynamic performance of the CLDPSs, for which a new parametric design of the LC filter circuit is proposed, aiming to achieve a balance between these two aspects. Finally, a voice coil motor driving platform is constructed for experimental testing. The results demonstrate that the output ripple and dynamic performance of the CLDPSs can be balanced. In comparison to the DC power supply mode, the CLDPSs power supply mode can enhance the efficiency of LPA by 2 times while the driving accuracy of voice coil motor is basically unchanged. [ABSTRACT FROM AUTHOR]

Given the presence of various non‐ideal conditions, such as detection errors, converter non‐linearity, noise, and parameter mismatches, the flux model experiences the introduction of DC bias and high‐frequency harmonics, which subsequently deteriorate the accuracy of flux estimation. To dispose these issues, an improved non‐linear flux observer (FOIFFO) using a second‐order generalised integrator as an in‐loop filter is proposed for the sensorless control of permanent magnet synchronous motors. The observer demonstrates robust performance in eliminating DC bias and having a strong filtering ability for high‐order harmonics even without amplitude and phase compensation to accurately estimate the rotational speed and rotor position. The performance of the method is analysed by transfer functions and bode plots, while the discretisation method of the FOIFFO is proposed. Finally, the new sensorless control strategy is verified by synthesising the experimental results. [ABSTRACT FROM AUTHOR]

The fuel cell hybrid test train requires methods to control fuel cell output power. The acceleration and regenerative-brake performance of the train varies with the SOC of the battery. And the energy consumption also varies with the passenger occupancy and the ambient temperature. Therefore, we studied the traction performance and fuel consumption depending on the difference of the control methods and the number of parameters to be considered with using a driving energy simulator. [ABSTRACT FROM AUTHOR]

This article is concerned with the stability issue of PI-based load frequency control (LFC) systems with time-varying delays and load interference. Firstly, a novel augmented Lyapunov–Krasovskii functional (LKF) is developed, in which the single integral term includes the augmented s-dependent integral term of delay-partition. For the purpose of coordinating with the constructed LKF effectively, a generalised free-matrix-based integral inequality and quadratic inequality are utilised to estimate the functional derivatives accurately, so that the stability criterion of less conservative is obtained. Finally, the relationship between the PI gains and the delay margins is presented, and the effects of time delays and PI gains on the system dynamic performance are discussed simultaneously by simulation. The simulation results verify the validity of the proposed method. [ABSTRACT FROM AUTHOR]

This paper compares the performance of a Sliding Mode Control (SMC) and Proportional-Integral (PI) controller under different voltage and load conditions. The study's findings underscore the need to account for load variations in system designs and to continuously seek system optimization irrespective of the controller type chosen. PI controller demonstrates effectiveness under certain circumstances. However, significant drops in voltage and current during abrupt load changes are obtained. On the other hand, SMC enables superior adaptability, efficiently managing voltage transients and load variations without any electrical disturbances, thereby maintaining system stability. A comparative analysis further emphasizes the SMC's superior time response and robustness against reference voltage changes. Consequently, SMC is proven to be a preferable choice over the PI controller in systems experiencing frequent voltage and load variations. However, both controllers achieve the potential for further response time optimization and stability. [ABSTRACT FROM AUTHOR]

This paper proposes an improved two‐degree‐of‐freedom active disturbance rejection controller for the coupling problem of asynchronous motor vector system. To simplify the analysis process and accommodate observers of different types, a unified expression based on different controllers for the system output is developed. The closed‐loop transfer function generated by the reference input and load disturbance is given. For the coupling problem of motor output speed and immunity, the structure of a higher‐order extended state observer is reconstructed. The extended state observer estimates both the output speed and the total system disturbance, which serve as feedback and feed‐forward compensation quantities. Compared to the PI controller and traditional active disturbance rejection controller, the proposed controller achieves decoupling of output response speed and immunity, simplifies the process of parameter tuning. Finally, simulation and experiment results verify the feasibility and effectiveness of the algorithm in this paper. [ABSTRACT FROM AUTHOR]

A vast number of mass flow controllers (MFCs) are used in semiconductor industry. For the stable supply, an efficient production method of MFC is required. The gain tuning of the proportional-integral (PI) control to realize a setting flow rate is essential for efficient mass production. The gains are tuned to meet the specifications required for evaluation indices of response time and overshoot amount in a step response waveform. The tuning is complicated especially for the case of pressure-based MFCs. In this paper, we propose a simple method for the PI gain tuning using the Gaussian mixture model (GMM) and the direct inverse analysis applicable to the pressure-based MFCs' production. The relationship between the gains and evaluation indices for a standard unit of the MFC is modeled as the GMM. The direct inverse analysis calculates the difference between the standard and a test unit. Under the assumption that the difference can be compensated by a simple shift, gains likely to meet the specifications for the test unit are searched. We applied the method to seven test units. The result showed that the gains of all the test units were tuned within only a few iterations whose numbers were much less than the conventional manual tuning method, and there was no untunable unit. [ABSTRACT FROM AUTHOR]

This article presents a buck converter in which the inductor has been replaced by a transmission line. This approach would be practically conceivable if the power supply and load had a greater spatial distance. Alternatively, the model derived in this way could also be regarded as an intermediate model in order to replace a power coil via discretization with a larger number of smaller coils and capacitors. In the time domain, this new converter can be described by a system of coupled partial and ordinary differential equations. In the frequency domain, a transcendental transfer function is obtained. For comparison with an equivalently parameterized conventional converter, Padé approximants are derived. A linear controller is designed for the converter topology under consideration. [ABSTRACT FROM AUTHOR]

Abstract Wireless power transfer (WPT) is a promising technology and has attracted many researchers’ attention due to its inherent advantages such as reliability, safety, flexibility, and low maintenance costs. For WPT systems, the output voltage varies according to the variable loads and the coupling coefficient conditions, affecting system stability and efficiency. In this regard, this study is concerned with the tracking control problem of WPT systems based on fuzzy supervisory proportional–integral (PI) controller and a phase shift modulation technique, which is for the first time proposed by this paper. By introducing appropriate fuzzy rules, the proposed control scheme not only can track the desired output voltage but also has better robust behaviour to deal with the problem of variations of circuit elements and coupling coefficients. That is, the proposed fuzzy supervisory PI control scheme can perform better than the traditional PI controller. Analysis of the designed control method and simulation results validate the superiority of the proposed method over the traditional PI controller in all conditions, which can make it a suitable choice for the applications of electric vehicle charging systems. The analysis is supported by experimental measurements.

Conical tanks have a high application rate in industrial processes, especially in colloidal mills, chemical processes, and food processing. The use of conical tanks presents significant benefits because they contribute to sedimentation and reduce the accumulation of impurities compared to conventional cylindrical tanks. However, level control of a conical tank due to its shape requires advanced strategies to guarantee efficient control. In this research, a model predictive control (MPC) method was designed and implemented for the level control of a conical tank on a laboratory scale. To evaluate the performance of the controller, it was compared with a traditional proportional–integral (PI) controller, and the rise time, settling time, overshoot, and error in the steady state were analyzed when different set point changes were tested. In addition, the system was subjected to disturbances, and the MPC demonstrated better performance in a transient state, as well as smooth and stable action controls that allowed for an increase in the useful life of the actuator. In addition, an interactive graphical interface was developed that allowed a dynamic response in a real plant to be experienced; this provides an academic tool for designing control strategies before implementation in a real process. [ABSTRACT FROM AUTHOR]

Static Synchronous Compensator (STATCOM) is a self-tuning proportional-integral (PI) controller that has been developed to handle the voltage and reactive power of Cascaded H-Bridges (CHB-STATCOM) in order to improve the power system. The purpose of optimizing controller parameters for a Multilevel Converter-based STATCOM (Static Synchronous Compensator) in the context of reactive power compensation is to enhance the performance and efficiency of the STATCOM system in regulating the power factor and voltage of an electrical system. This controller was introduced in this article. This research presented that the STATCOM should have the capability to operate both in inductive and capacitive mode of operation and absorb or injects the desired amount of reactive power into the grid. The reactionary power that is received or supplied contributes to the improvement of the power system. The benefits of the self-tuning PI controller have been optimized to their full potential through the use of Accelerated Particle Swarm Optimization (APSO) strategies. The STATCOM is implemented into the electrical system, and its reaction to varying reactive and voltage levels is analyzed as part of the process of determining whether or not the optimization techniques are successful. Two controllers are now in operation at the STATCOM. The first controller is in charge of managing the DC voltage, and the second controller is in charge of controlling the reactive power. Both controllers are in use at the same time. The output of the controller is then transferred to the phase change carrier, which is followed by pulse width modulation in a sinusoidal pattern. Because of this, the power converter switch may now function properly. [ABSTRACT FROM AUTHOR]

Even though the energy penalties and solvent regeneration costs associated with amine-based absorption/stripping systems are important challenges, this technology remains highly recommended for post-combustion decarbonization systems given its proven capture efficacy and technical maturity. This study introduces a novel centralized and decentralized hybrid control strategy for the post-combustion carbon capture plant, aimed at mitigating main disturbances and sustaining high system performance. The strategy is rooted in a comprehensive mathematical model encompassing absorption and desorption columns, heat exchangers and a buffer tank, ensuring smooth operation and energy efficiency. The buffer tank is equipped with three control loops to finely regulate absorber inlet solvent solution parameters, preventing disturbance recirculation from the desorber. Additionally, a model-based controller, utilizing the model predictive control (MPC) algorithm, maintains a carbon capture yield of 90% and stabilizes the reboiler liquid temperature at 394.5 K by manipulating the influent flue gas to the lean solvent flowrates ratio and the heat duty of the reboiler. The hybrid MPC approach reveals efficiency in simultaneously managing targeted variables and handling complex input–output interactions. It consistently maintains the controlled variables at desired setpoints despite CO2 flue gas flow disturbances, achieving reduced settling time and low overshoot results. The hybrid control strategy, benefitting from the constraint handling ability of MPC, succeeds in keeping the carbon capture yield above the preset minimum value of 86% at all times, while the energy performance index remains below the favorable value of 3.1 MJ/kgCO2. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) is a promising technology and has attracted many researchers' attention due to its inherent advantages such as reliability, safety, flexibility, and low maintenance costs. For WPT systems, the output voltage varies according to the variable loads and the coupling coefficient conditions, affecting system stability and efficiency. In this regard, this study is concerned with the tracking control problem of WPT systems based on fuzzy supervisory proportional–integral (PI) controller and a phase shift modulation technique, which is for the first time proposed by this paper. By introducing appropriate fuzzy rules, the proposed control scheme not only can track the desired output voltage but also has better robust behaviour to deal with the problem of variations of circuit elements and coupling coefficients. That is, the proposed fuzzy supervisory PI control scheme can perform better than the traditional PI controller. Analysis of the designed control method and simulation results validate the superiority of the proposed method over the traditional PI controller in all conditions, which can make it a suitable choice for the applications of electric vehicle charging systems. The analysis is supported by experimental measurements. [ABSTRACT FROM AUTHOR]

This article describes the use of a sliding mode controller (SMC) in conjunction with an integral (PI) controller for a MLI based DSTATCOM to balance DC side voltage, control a cascaded H-bridge inverter, and compensate for power quality issues related to current harmonics. Several benefits come with using SMC for distribution static synchronous compensator (DSTATCOM) link voltage regulation, including a decrease in switching ripple in the DC side voltage and a steady DC side capacitor voltage under dynamic conditions. A DSTATCOM-based CHBMLI supplying threephase loads is used to implement the SMC algorithm. When using the suggested dc link voltage balancing method, the DSTATCOM characteristics perform satisfactorily in terms of voltage balancing and the removal of power quality issues such as current harmonics. Additionally, the DSTATCOM’s improved voltage balancing (IVB) scheme is used to compare the performance of the PI controller with the SMC’s improved voltage balancing method. The real-time investigation validates the performance characteristics, and the enhanced voltage balancing scheme of SMC results in better transient and steady state response. [ABSTRACT FROM AUTHOR]

The metal manufacturing industry employs the reversible cold rolling mill, which is a machine used to process and shape various metal products such as steel sheets, aluminum sheets, and copper sheets. High accuracy control of web velocity and web tension is essential in the manufacturing process for preventing the web from bending or breaking during the entire manufacturing process. In this work, we introduce a control law design method using PI control with unknown parameters for the web winding system to ensure that the final product will not be affected by deformation or breakage. In the first step of the adaptive backstepping procedure, the integral action is obtained by adding the integral of the tracking error to the error considered. The stability of the control design is ensured by the Lyapunov stability theorem. It verifies that the trajectory dynamics are asymptotically stable. To illustrate the effectiveness and performance of the proposed controllers, simulation studies using the MATLAB/Simulink environment are presented. [ABSTRACT FROM AUTHOR]

This letter presents a hybrid control of robot vehicle using the behavior cloning algorithm with PID control for enhanced driving performance. The behavior cloning algorithm based on the convolutional neural network (CNN) has been implemented to the autonomous driving algorithm of a robot vehicle by implementing a supervised learning approach. The algorithm mimics human driving behaviors for autonomous driving by obtaining and learning manual(human) control data. In order to implement the algorithm on the real system, a low-cost camera sensor and controllers with actuators are used so that it achieves robust driving performance. With a successfully developed and validated CNN-based behavior cloning model, a classic PID control algorithm has been combined as a lateral controller to propose an AI-powered hybrid control architecture which improves the performance of trajectory tracking in various environments using the proposed behavior cloning algorithm. The performance of the proposed algorithm has been evaluated via robot vehicle tests. It has been shown from the simulation studies and vehicle tests that the proposed algorithm enhances driving performance. [ABSTRACT FROM AUTHOR]

This study numerically investigates mixed convective cooling in a two‐dimensional horizontal channel containing periodically heated blocks by applying proportional (P), proportional‐integral (PI), and proportional‐integral‐derivative (PID) controllers. Three different controller configurations regulate the amount of cold air entering the chamber. The air's non‐dimensional temperature is continuously monitored at the set point to compare the controllers' performance, and the percentage of overshoot and the steady‐state error are analysed. The investigated chamber comprises one inlet and two exit ports, a temperature sensor, and two heated blocks that are isotherm heat sources. The Galerkin finite element approach computationally solves the equations of continuity, momentum, and energy to analyse the thermo‐fluid phenomena occurring within the chamber. Parametric simulation is carried for different values of the proportional gain (Kp = 0.005, 0.010, 0.050 m s−1 K−1), the integral gain (Ki = 0.05, 0.10, 0.15 m s−2 K−1), the derivative gain (Kd = 10−5, 10−4, 10−3 m K−1) to achieve a consistent and expeditious response. Variations of Reynolds, Richardson, and mean Nusselt numbers with time are plotted to compare the system's performance. The investigation indicates that the PI controller produces a comparable level of performance with the PID controller, reducing the necessity to add a derivative controller. [ABSTRACT FROM AUTHOR]

The global shift towards fuel cell hybrid electric vehicles (FHEVs) is motivated by rising fuel costs and environmental concerns related to emissions. This study evaluates two energy management strategies in a hybrid electric vehicle equipped with a proton exchange membrane fuel cell (PEMFC) as the primary power source and a lithium-ion battery as a secondary source. A traditional proportional-integral (PI) strategy and an intelligent fuzzy logic-based control (FLC) strategy are compared to optimize energy flow and minimize fuel consumption. Both algorithms studied generate the reference power of the PEM fuel cell for each state of charge level of the Li-ion battery and the required power of the vehicle. Simulation results, using the NYCC drive cycle, demonstrate that the fuzzy logic-based control strategy mitigates voltage fluctuations, reduces battery discharging, and hydrogen consumption, thereby improving transient response. [ABSTRACT FROM AUTHOR]

This article presents the results of simulation research of a diesel engine for a light helicopter. The simulations were performed using the 1D software AVL Boost RT. The engine model includes elements such as cylinders, turbine, compressor, inlet and outlet valves, ambient environment definition, and fuel injection control strategy. The simulations aimed to evaluate the engine's response to step changes in the main rotor load, both increasing and decreasing power demands. Parameters analyzed included power deviation, torque, engine rotational speed, and stabilization time of the main rotor rotational speed. All tests were conducted using a single set of PI controller settings. The results demonstrate that these parameters are dependent on the magnitude of the step change in the main rotor load demand. The study compares the maximum engine rotational speed deviation from the nominal value for both increasing and decreasing main rotor load demands. The findings indicate that using PI regulator to control rotational speed in the diesel engine in a light helicopter significantly depends on the change in the load torque on the rotor.

Abstract This paper extends the characteristic ratio approach using novel inequalities to ensure zero/low overshoot for linear‐time‐invariant systems with zeros. The extension provided by this paper is based on the maximally‐flatness property of a transfer function, where the square‐magnitude of the transfer function is ensured to be a low‐pass filter. In order to be able to design low‐order/fixed structure controllers, a partial pole‐assignment approach is used instead of the full pole‐assignment used in the Characteristic Ratio Assignment (CRA) method. The developed inequalities and additional stability conditions are combined into an optimization problem using time domain restrictions when necessary. Although the method given in the paper is general, particular inequalities are developed for PI and PI‐PD controller cases, due to their frequent use in industrial applications. Similarly, First‐Order‐Plus‐Delay‐Time (FOPDT) and Second‐Order‐Plus‐Delay‐Time (SOPDT) systems are considered specifically, since most of the practical systems can be approximated by one of these types. The study is extended to plants with uncertainties where a theorem is developed to decrease computation time dramatically. The benefits of the proposed methods are demonstrated by several examples.

This paper extends the characteristic ratio approach using novel inequalities to ensure zero/low overshoot for linear‐time‐invariant systems with zeros. The extension provided by this paper is based on the maximally‐flatness property of a transfer function, where the square‐magnitude of the transfer function is ensured to be a low‐pass filter. In order to be able to design low‐order/fixed structure controllers, a partial pole‐assignment approach is used instead of the full pole‐assignment used in the Characteristic Ratio Assignment (CRA) method. The developed inequalities and additional stability conditions are combined into an optimization problem using time domain restrictions when necessary. Although the method given in the paper is general, particular inequalities are developed for PI and PI‐PD controller cases, due to their frequent use in industrial applications. Similarly, First‐Order‐Plus‐Delay‐Time (FOPDT) and Second‐Order‐Plus‐Delay‐Time (SOPDT) systems are considered specifically, since most of the practical systems can be approximated by one of these types. The study is extended to plants with uncertainties where a theorem is developed to decrease computation time dramatically. The benefits of the proposed methods are demonstrated by several examples. [ABSTRACT FROM AUTHOR]

In the current landscape of renewable energy systems, optimizing the performance of power electronic converters is crucial for ensuring reliability. Within the realm of direct current (DC)–DC power converter systems, the differential power processing (DPP) converter holds promise. However, realizing its full potential requires meticulous system design, especially in response to varying solar irradiation levels. Poor design can result in performance degradation, leading to system damage and voltage instability due to sudden irradiation fluctuations. To address these challenges, this study investigates the performance optimization of a DPP converter enhanced with a modified switched inductor, tailored for solar photovoltaic applications. To overcome traditional control strategy limitations, we propose an innovative enhanced fuzzy logic controller (E-FLC). This controller's strength lies in its dynamic adaptability, achieved through variable duty cycle control, input parameters, membership functions, and output responses. This paper emphasizes methodological precision, particularly in applying the E-FLC to the modified switched inductor. The use of this controller significantly improves both steady-state and transient response performance compared to traditional switched inductors. It rigorously analyzes the responses of the DPP converter under steady-state and transient conditions, with and without the modified switched inductor. This analytical approach sheds light on a critical yet often overlooked aspect of photovoltaic systems. The core innovation driving this research is the adoption of the E-FLC, which outperforms the commonly used proportional–integral (PI) controller in steady-state performance and transient response characteristics. This paper goes beyond conventional converter optimization studies by introducing a holistic approach encompassing system dynamics, control strategy innovation, and performance evaluation. The proposed E-FLC represents a methodological breakthrough and a substantial improvement in converter efficiency and reliability. As renewable energy continues to reshape the global energy landscape, this research sets a new standard for harnessing the true capabilities of power electronic converters in solar photovoltaic systems. [ABSTRACT FROM AUTHOR]

The objective of this work is to design and implement an adaptive control in conjunction with vector control, with changes in the desired dynamics for the positioning of two degrees of freedom robotic arms. The dynamic model is obtained by applying the Euler-Lagrange method in conjunction with that of a permanent magnet synchronous motor in the synchronous DQ reference frame. An adaptive controller is designed by reference model that generates the reference torque for the vector control of the electric motor. The stability of the closed-loop system is guaranteed by applying the Lyapunov method in the adaptive laws. The control strategy is implemented on the TMS320F28335 processor using the MATLAB and Code Composer tools. The results of the experimental tests are compared with the original control scheme, obtaining a system with lower dynamic errors. [ABSTRACT FROM AUTHOR]

Redundant power supplies are commonly used in systems that require long-term uninterrupted operation and high reliability. When redundant power supplies are used as N+1 backup power supplies to supply power to devices at the same time, parallel current sharing must be considered.In order to solve the problem of large loss of passive redundant power supply and inability to achieve current equalization, this study adopts the design scheme of active redundancy and designs a 1+1 redundant power supply system with two parallel DC voltage inputs.The system uses GD32E103 as the main control chip. By changing the on-resistance of MOSFET(Metal-Oxide Semiconductor Field Effect Transistor), PI(Proportional Integral) control is adopted to realize the automatic balance of the output current of two redundant power supplies.The simulation and experimental results show that the active redundancy design scheme can achieve the purpose of automatic current equalization.In normal operation, the maximum error of the two current channels is less than 0.1 A, and the accuracy of current sharing meets the design requirements. [ABSTRACT FROM AUTHOR]

This article presented simulation and control of a liquid oxygen/liquid methane variable thrust rocket engine pressurized by the electric pump in the throttling process. To get a proper injection pressure drop, the variation of the injection area was investigated and determined. In the control scheme, the combustion pressure and mixture ratio were the targets. To simplify the control scheme, the pressure and mixture ratio were correlated to the oxygen mass flow rate and methane mass flow rate, respectively. By controlling the propellant mass flow rate, the target engine thrust was reached. In addition, the influence of mass flow rate measurement points on the control effect was analyzed. The simulation results showed that the designed controller can reduce the overshoot of the critical engine parameters. Therefore, the maximum temperature of the thrust chamber wall after the regenerative cooling was decreased. Consequently, the thrust control errors were within 3% except for the points where the thrust changed suddenly, which can meet the mission requirements. [ABSTRACT FROM AUTHOR]

The present work presents the design and implementation of a non-isolated DC/DC Boost converter, operating with a nominal load of 20 W, a constant output voltage of 24 V, and a variable input voltage of 12 ± 25%. The development was carried out in the Power Electronics laboratories of the Electromechanical Engineering program at Universidad Francisco de Paula Santander, following the proposed solution methodology. The results demonstrate that the implemented PI control system improves the dynamic response of the converter in closed loop compared to the open loop, with steady-state errors ranging from 1.66% (for a Vin of 9V) to 3.33% (for a Vin of 12V and 15V) relative to the desired 24 V output. The system successfully stabilizes the output voltage against different input voltage variations, highlighting the importance of control systems and simulation tools in the design and analysis of power electronics circuits. [ABSTRACT FROM AUTHOR]

The output rotational speed of the servo drive system fluctuates due to the influence of environmental disturbances and the flexibility of the flexible manipulator with variable length during the process of rotation. The phenomenon will exacerbate the vibration of the flexible manipulator and affect the motion accuracy of the flexible manipulator seriously. Therefore, a proportional‑integral (PI) control strategy based on the disturbance observer is designed to suppress the rotational speed fluctuation of the servo drive system. Firstly, the dynamic model of the dual‑flexible servo blrive system was established and the transmission characteristics of the dual‑flexible servo drive system were analyzed by using the Lagrange’s theorem. Then the PI control strategy based on the disturbance observer was applied to the speed loop in the dual‑flexible servo drive system. The low pass filter parameters of the disturbance observer were designed by robust stability analysis. Finally, numerical simulation analysis and control experiments were carried out. The results verify that the proposed control strategy can effectively reduce the rotational speed fluctuation of the flexible manipulator with variable length and improve the motion accuracy of the servo drive system. [ABSTRACT FROM AUTHOR]

This paper addresses the stabilization of a general class of linear single-input/single-output (SISO) second-order non-minimum phase systems with input channel delays using Proportional-Integral (PI) controllers. Such systems arise in various applications, including power electronic circuits and biochemical reactors. The primary goal is to enhance system performance by determining optimal control gains that shift the spectral abscissa of the closed-loop system as far to the left as possible, thereby improving its decay rate. To achieve this, we introduce a geometric framework that characterizes the stability region of the closed-loop system in three distinct cases. Our main contribution is a systematic tuning approach to achieve the desired decay rate when feasible. Additionally, we discuss the controller’s fragility and the delay margin of the closed-loop system to ensure practical applicability. The effectiveness of the proposed method is demonstrated through numerical simulations for each scenario. Finally, two practical case studies—a boiler steam drum and a DC-DC boost converter—are presented to illustrate the results’ relevance in practice.