Actuators

13 pages, 3359 KB

Open AccessArticle

In-Situ Validation and Performance Analysis of Polymer-Dispersed Liquid Crystal Films for Dynamic Natural Light Control in Smart Greenhouses

by Chiara Vetter, Peyton I. Mann and Alexander H. Pesch

Actuators 2025, 14(10), 500; https://doi.org/10.3390/act14100500 - 15 Oct 2025

Abstract

Polymer-Dispersed Liquid Crystal (PDLC) films offer a promising actuation method for dynamically controlling natural light, particularly in applications like smart greenhouses that require optimized Photosynthetically Active Radiation (PAR). Building upon previous work that established a control-oriented model and validated it under laboratory conditions, [...] Read more.

Polymer-Dispersed Liquid Crystal (PDLC) films offer a promising actuation method for dynamically controlling natural light, particularly in applications like smart greenhouses that require optimized Photosynthetically Active Radiation (PAR). Building upon previous work that established a control-oriented model and validated it under laboratory conditions, this study presents significant extensions. Key novel contributions include (1) the design and implementation of a Mini Greenhouse (MGH) test rig featuring PDLC films angled at 45° to accommodate typical sun angles; (2) extensive in situ validation of the previously developed Proportional–Integral (PI) control scheme under real-world environmental conditions, including varying natural sunlight, cloud cover, rain, and snow over several weeks; (3) analysis of system performance at different PAR setpoints (4 PAR and 10.5 PAR) under these conditions; (4) characterization of the system’s controllable PAR range and transmittance under natural light; (5) calculation of a light reduction ratio attributable to the MGH structure for accurate disturbance modeling; and (6) validation of an extended simulation model using the collected in situ data. The results demonstrate the system’s capability to effectively track setpoints and reject disturbances under dynamic natural light, confirming the robustness of the PDLC control approach. The validated simulation provides a reliable tool for predicting performance and optimizing control strategies for energy-efficient smart greenhouse applications. This work significantly advances the practical assessment of PDLC actuators for agricultural light management beyond laboratory settings. Full article

(This article belongs to the Section Control Systems)

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23 pages, 5673 KB

Open AccessArticle

Numerical Investigation of a Morphing Wing Section Controlled by Piezoelectric Patches

by Mario Rosario Chiarelli, Vincenzo Binante, Salvatore Bonomo, Stefano Botturi, Luca Giani, Jan Kunzmann, Aniello Cozzolino and Diego Giuseppe Romano

Actuators 2025, 14(10), 499; https://doi.org/10.3390/act14100499 - 15 Oct 2025

Abstract

One of the tasks of the FutureWings project, funded by the European Commission within the 7th framework, was to numerically validate the mechanical behavior of a wing whose deflections had to be controlled via a suitable distribution of piezoelectric patches. Starting from a [...] Read more.

One of the tasks of the FutureWings project, funded by the European Commission within the 7th framework, was to numerically validate the mechanical behavior of a wing whose deflections had to be controlled via a suitable distribution of piezoelectric patches. Starting from a reference geometry (a NACA 0012 airfoil), wing profiles were implemented and analyzed using the fluid–structure interaction analysis technique. The wing section was designed with a morphing profile in which both the front and rear parts self-deform via piezoelectric patches that serve actuators glued to the skin of the profile. A Macro Fiber Composite (MFC) was used as the piezoelectric actuator. Aeroelastic analyses were performed at low Mach numbers under the sea-level flight condition. Analysis of the technical solution was based on an examination of the aerodynamic coefficients and polar curves of the profile, as the control voltage of the patches can vary. The results were compared with those available in the literature. As a preliminary step, this work contributes to examining the current technical possibilities of this technology relating to the application of piezoelectric patches as actuators in the field of aerostructures. Full article

(This article belongs to the Special Issue Aerospace Mechanisms and Actuation—Second Edition)

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25 pages, 9469 KB

Open AccessArticle

Optimization and Experimental Investigation of a Single-Actuation Compliant Morphing Trailing Edge for Multiple Aerodynamic Configurations

by Martynas Lendraitis and Vaidas Lukoševičius

Actuators 2025, 14(10), 498; https://doi.org/10.3390/act14100498 - 15 Oct 2025

Abstract

This work presents a low-fidelity optimization method for a compliant morphing wing trailing-edge structure, developed to achieve multiple optimized aerodynamic shapes under combined aerodynamic and control loads using a single actuation pathway. Typically, multiple shape configurations are avoided due to conflicting structural requirements [...] Read more.

This work presents a low-fidelity optimization method for a compliant morphing wing trailing-edge structure, developed to achieve multiple optimized aerodynamic shapes under combined aerodynamic and control loads using a single actuation pathway. Typically, multiple shape configurations are avoided due to conflicting structural requirements that increase optimization complexity. To address this, a parameterization method based on practical considerations of compliant trailing-edge structures is introduced. A particle swarm optimization algorithm is employed, with multi-objective criteria handled through a penalty-based approach. The algorithm is demonstrated by optimizing the trailing edge for one and two aerodynamic configurations with high accuracy, achieving typical shape deviations of 0.04% and 0.08% relative to the chord for two shapes, and as low as 0.023% for a single shape. Several compliant structures are generated, manufactured, and tested for shape accuracy, including in a wind tunnel to evaluate aerodynamic performance. Experimental investigations confirm the feasibility of achieving two aerodynamic shape configurations with a single structure and show that the proposed methodology can improve the lift-to-drag ratio of a wing section with a deflected compliant trailing edge by more than 12.4% compared to conventional flaps at the same deflection. Full article

(This article belongs to the Special Issue Aerospace Mechanisms and Actuation—Second Edition)

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20 pages, 6970 KB

Open AccessArticle

Dynamic Parameter Identification Method for Space Manipulators Based on Hybrid Optimization Strategy

by Haitao Jing, Xiaolong Ma, Meng Chen and Jinbao Chen

Actuators 2025, 14(10), 497; https://doi.org/10.3390/act14100497 - 15 Oct 2025

Abstract

High-precision identification of dynamic parameters is crucial for the on-orbit performance of space manipulators. This paper investigates dynamic modeling and parameter identification under special environmental conditions such as microgravity and vacuum. First, a dynamic model of the manipulator incorporating a nonlinear friction term [...] Read more.

High-precision identification of dynamic parameters is crucial for the on-orbit performance of space manipulators. This paper investigates dynamic modeling and parameter identification under special environmental conditions such as microgravity and vacuum. First, a dynamic model of the manipulator incorporating a nonlinear friction term is established using the Newton-Euler method, and an improved Stribeck friction model is proposed to better characterize high-speed conditions and space environmental effects. On this basis, a hybrid parameter identification method combining Particle Swarm Optimization (PSO) and Levenberg–Marquardt (LM) algorithms is proposed to balance global search capability and local convergence accuracy. To enhance identification performance, Fourier series are used to design excitation trajectories, and their harmonic components are optimized to improve the condition number of the observation matrix. Experiments conducted on a ground test platform with a six-degree-of-freedom (6-DOF) manipulator show that the proposed method effectively identifies 108 dynamic parameters. The correlation coefficients between predicted and measured joint torques all exceed 0.97, with root mean square errors below 5.1 N·m, demonstrating the high accuracy and robustness of the method under limited data samples. The results provide a reliable model foundation for high-precision control of space manipulators. Full article

(This article belongs to the Special Issue Dynamics and Control of Aerospace Systems—2nd Edition)

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20 pages, 3107 KB

Open AccessArticle

Observer-Based Volumetric Flow Control in Nonlinear Electro-Pneumatic Extrusion Actuator with Rheological Dynamics

by Ratchatin Chancharoen, Chaiwuth Sithiwichankit, Kantawatchr Chaiprabha, Setthibhak Suthithanakom and Gridsada Phanomchoeng

Actuators 2025, 14(10), 496; https://doi.org/10.3390/act14100496 - 14 Oct 2025

Abstract

Consistent volumetric flow control is essential in extrusion-based additive manufacturing, particularly when printing viscoelastic materials with complex rheological properties. This study proposes a control framework incorporating simplified rheological dynamics via a Kelvin–Voigt model that integrates nonlinear dynamic modeling, an unknown input observer (UIO), [...] Read more.

Consistent volumetric flow control is essential in extrusion-based additive manufacturing, particularly when printing viscoelastic materials with complex rheological properties. This study proposes a control framework incorporating simplified rheological dynamics via a Kelvin–Voigt model that integrates nonlinear dynamic modeling, an unknown input observer (UIO), and a closed-loop PID controller to regulate material flow in a motorized electro-pneumatic extrusion system. A comprehensive state-space model is developed, capturing both mechanical and rheological dynamics. The UIO estimates unmeasurable internal states—specifically, syringe plunger velocity—which are critical for real-time flow regulation. Simulation results validate the observer’s accuracy, while experimental trials with a curing silicone resin confirm that the system can achieve steady extrusion and maintain stable linewidth once transient disturbances settle. The proposed system leverages a dual-mode actuation mechanism—combining pneumatic buffering and motor-based adjustment—to achieve responsive and robust control. This architecture offers a compact, sensorless solution well-suited for high-precision applications in bioprinting, electronics, and soft robotics, and provides a foundation for intelligent flow regulation under dynamic material behaviors. Full article

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28 pages, 88379 KB

Open AccessArticle

Identification and Fuzzy Control of the Trajectory of a Parallel Robot: Application to Medical Rehabilitation

by Elihu H. Ramirez-Dominguez, José G. Benítez-Morales, Jesus E. Cervantes-Reyes, Ma. de los Angeles Alamilla-Daniel, Angel R. Licona-Rodríguez, Juan M. Xicoténcatl-Pérez and Julio Cesar Ramos-Fernández

Actuators 2025, 14(10), 495; https://doi.org/10.3390/act14100495 - 13 Oct 2025

Abstract

A specific challenge in robotic control applications is the identification and regulation of actuators that provide mechanical traction and motion to the robot links. The design of actuator control laws, grounded in parametric identification and experimental motor characterization, enables numerical simulations to explore [...] Read more.

A specific challenge in robotic control applications is the identification and regulation of actuators that provide mechanical traction and motion to the robot links. The design of actuator control laws, grounded in parametric identification and experimental motor characterization, enables numerical simulations to explore diverse operating scenarios. This article presents the initial phases in the development of a robotic rehabilitation system, focused on the kinematic modeling of a parallelogram-configuration robot for upper-limb therapy, the fuzzy identification of its actuators, and their closed-loop evaluation using a fuzzy Parallel Distributed Compensation (PDC) controller with state feedback (Ackermann), whose poles are optimized via the Grey Wolf Optimizer (GWO) metaheuristic. This controller was selected for its congruence with the nonlinear universe of discourse defined by the identified model, a key feature for operation within specific functional ranges in medical applications. The simulation and hardware platform results provide evidence that fuzzy dynamic models constitute a valuable tool for application in rehabilitation systems. This work serves as a foundation for future physical implementations with the fully coupled robotic system, in order to ensure operational safety prior to the start of clinical trials. Full article

(This article belongs to the Special Issue Actuators and Robotic Devices for Rehabilitation and Assistance—2nd Edition)

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21 pages, 3934 KB

Open AccessArticle

Quadratic Programming Vision-Based Control of a Scale-Model Autonomous Vehicle Navigating in Intersections

by Esmeralda Enriqueta Mascota Muñoz, Oscar González Miranda, Xchel Ramos Soto, Juan Manuel Ibarra Zannatha and Santos Miguel Orozco Soto

Actuators 2025, 14(10), 494; https://doi.org/10.3390/act14100494 - 12 Oct 2025

Abstract

This paper presents an optimal control for autonomous vehicles navigating in intersection scenarios. The proposed controller is based on solving a Quadratic Programming optimization technique to provide a feasible control signal respecting actuator constraints. The proposed controller was implemented in a scale-sized vehicle [...] Read more.

This paper presents an optimal control for autonomous vehicles navigating in intersection scenarios. The proposed controller is based on solving a Quadratic Programming optimization technique to provide a feasible control signal respecting actuator constraints. The proposed controller was implemented in a scale-sized vehicle and is executed using only on-board perception and computing systems to retrieve the state dynamics, i.e., an inertial measurement unit and a monocular camera, to compute the estimated states through intelligent computer vision algorithms. The stability of the error signals of the closed-loop system was proved both mathematically and experimentally, using standard performance indices for ten trials. The proposed technique was compared against LQR and MPC strategies, showing 67% greater accuracy than the LQR approach and 53.9% greater accuracy than the MPC technique, while turning during the intersection. Moreover, the proposed QP controller showed significantly greater efficiency by reducing the control effort by 63.3% compared to the LQR, and by a substantial 78.4% compared to the MPC. These successful results proved that the proposed controller is an effective alternative for autonomously navigating within intersection scenarios. Full article

(This article belongs to the Special Issue Nonlinear Control of Mechanical and Robotic Systems)

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17 pages, 2107 KB

Open AccessArticle

FVSMPC: Fuzzy Adaptive Virtual Steering Coefficient Model Predictive Control for Differential Tracked Robot Trajectory Tracking

by Pu Zhang, Xiubo Xia, Yongling Fu and Jian Sun

Actuators 2025, 14(10), 493; https://doi.org/10.3390/act14100493 - 12 Oct 2025

Abstract

Differential tracked robots play a crucial role in various modernized work scenarios such as smart industry, agriculture, and transportation. However, these robots frequently encounter substantial challenges in trajectory tracking, attributable to substantial initial errors and dynamic environments, which result in slow convergence rates, [...] Read more.

Differential tracked robots play a crucial role in various modernized work scenarios such as smart industry, agriculture, and transportation. However, these robots frequently encounter substantial challenges in trajectory tracking, attributable to substantial initial errors and dynamic environments, which result in slow convergence rates, cumulative errors, and diminished tracking precision. To address these challenges, this paper proposes a fuzzy adaptive virtual steering coefficient model predictive control (FVSMPC) algorithm. The FVSMPC algorithm introduces a virtual steering coefficient into the robot’s kinematic model, which is adaptively adjusted using fuzzy logic based on real-time positional error and velocity. This approach not only enhances the robot’s ability to quickly correct large errors but also maintains stability during tracking.The nonlinear kinematic model undergoes linearization via a Taylor expansion and is subsequently formulated as a quadratic programming problem to facilitate efficient iterative solutions. To validate the proposed control algorithm, a simulation environment was constructed and deployed on a real prototype for testing. Results demonstrate that compared to the baseline algorithm, the proposed algorithm performs excellently in trajectory tracking tasks, avoids complex parameter tuning, and exhibits high accuracy, fast convergence, and good stability. This work provides a practical and effective solution for improving the trajectory tracking performance of differential tracked robots in complex environments. Full article

(This article belongs to the Special Issue Modeling, Perception and Control of Robotic Systems with Real-World Applications)

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19 pages, 4145 KB

Open AccessArticle

RM-Act: A Novel Modular Harmonic Actuator

by Ramesh Krishnan Muttathil Gopanunni, Alok Ranjan, Lorenzo Martignetti, Franco Angelini and Manolo Garabini

Actuators 2025, 14(10), 492; https://doi.org/10.3390/act14100492 - 11 Oct 2025

Abstract

In modern robotics, actuators are crucial for achieving effective movement and ensuring robustness. Although different applications demand specific actuator qualities, an actuator with built-in compliance and high torque density is generally preferred. Recently, harmonic gearboxes have become widely used in robotics for actuation [...] Read more.

In modern robotics, actuators are crucial for achieving effective movement and ensuring robustness. Although different applications demand specific actuator qualities, an actuator with built-in compliance and high torque density is generally preferred. Recently, harmonic gearboxes have become widely used in robotics for actuation due to their zero-backlash, lightweight design, flexibility, and high torque density. However, the intricate and precise machining required for these gearboxes makes them economically unviable in some cases. This work presents the RM-Act, a novel Radial Modular Actuator that employs synchronous belts as a harmonic speed reducer. The RM-Act retains the advantages of the harmonic principle, making it a promising candidate for robotic actuation. This paper describes the novel actuation principle and its validation through a prototype, along with a model identification to define its characteristics. The actuator demonstrates a nominal torque density of 10.08 N·m/kg, indicating its potential for efficient robotic applications. Full article

(This article belongs to the Special Issue Actuation and Sensing of Intelligent Soft Robots)

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37 pages, 5667 KB

Open AccessArticle

Depth Control of Variable Buoyancy Systems: A Low Energy Approach Using a VSC with a Variable-Amplitude Law

by João Bravo Pinto, João Falcão Carneiro, Fernando Gomes de Almeida and Nuno A. Cruz

Actuators 2025, 14(10), 491; https://doi.org/10.3390/act14100491 - 11 Oct 2025

Abstract

Underwater exploration relies heavily on autonomous underwater vehicles and sensor platforms for sustained monitoring of marine environments, yet their operational duration is limited by energy constraints. To enhance energy efficiency, various control strategies have been proposed, including robust, optimal, and disturbance-aware approaches. Recent [...] Read more.

Underwater exploration relies heavily on autonomous underwater vehicles and sensor platforms for sustained monitoring of marine environments, yet their operational duration is limited by energy constraints. To enhance energy efficiency, various control strategies have been proposed, including robust, optimal, and disturbance-aware approaches. Recent work introduced a variable structure controller (VSC) with a constant-amplitude control action for depth control of a platform equipped with a variable buoyancy module, achieving an average 22% reduction in energy use in comparison with conventional PID-based controllers. In a separate paper, the conditions for its closed-loop stability were proven. This study extends these works by proposing a controller with a variable-amplitude control action designed to minimize energy consumption. A formal proof of stability is provided to guarantee safe operation even under conservative assumptions. The controller is applied to a previously developed depth-regulated sensor platform using a validated physical model. Additionally, this study analyzes how the controller parameters and mission requirements affect stability regions, offering practical guidelines for parameter tuning. A method to estimate oscillation amplitude during hovering tasks is also introduced. Simulation trials validate the proposed approach, showing energy savings of up to 16% when compared to the controller using a constant-amplitude control action. Full article

(This article belongs to the Special Issue Advanced Underwater Robotics)

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21 pages, 3744 KB

Open AccessArticle

FPI-Based Adaptive Control with Simultaneous Noise Filtering and Low Frequency Delay

by Bence Varga, Richárd Horváth and József Kázmér Tar

Actuators 2025, 14(10), 490; https://doi.org/10.3390/act14100490 - 9 Oct 2025

Abstract

In the field of life sciences, delay effects are often modeled with two compartments that do not model any particular organ. In this paper the use of this double counterpart model is investigated in Fixed-Point Iteration-based (FPI) Control, which was introduced in 2009 [...] Read more.

In the field of life sciences, delay effects are often modeled with two compartments that do not model any particular organ. In this paper the use of this double counterpart model is investigated in Fixed-Point Iteration-based (FPI) Control, which was introduced in 2009 as an adaptive extension to the Computed Torque Control method. This controller is particularly sensitive to delays and measurement noise due to its iterative nature. It was recognized that, besides modeling the delay effect, this signal tackling also provided the controller with some noise filtering ability; the formerly accumulated effects of noise filtering and formally delayed sampling were avoided. This smeared delay has a noticeable effect even slightly later in time, making the adaptive method based on it more robust. This assumption was investigated both on a simulation and experimental basis. Full article

(This article belongs to the Section Control Systems)

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24 pages, 6824 KB

Open AccessArticle

Analytical Modeling and Simulation of Machinery Containing Hydraulic Lines with Fluid Transients

by David Hullender

Actuators 2025, 14(10), 489; https://doi.org/10.3390/act14100489 - 9 Oct 2025

Abstract

In industrial equipment containing hydraulic lines for power transmission, the lines have boundary conditions defined by components such as pumps, valves, and actuators located at the ends of the lines. Sudden changes in any of the boundary conditions may result in significant pressure/flow [...] Read more.

In industrial equipment containing hydraulic lines for power transmission, the lines have boundary conditions defined by components such as pumps, valves, and actuators located at the ends of the lines. Sudden changes in any of the boundary conditions may result in significant pressure/flow dynamics (fluid transients) in the lines that may be detrimental or favorable to the performance of the equipment. Accurate models for line transients are defined by the exact solution to a set of simultaneous partial differential equations. In this paper, analytical solutions to the partial differential equations provide Laplace transform transfer functions applicable to any set of boundary conditions yet to be specified that satisfy the requirements of causality. Analytical solutions of these partial differential equations from previous publications are reviewed for cases of laminar and turbulent flow for Newtonian and a class of non-Newtonian fluids. This paper focuses on a method for obtaining total system analytical models and time domain solutions for cases in which the end-of-line components can be modeled with linear equations for perturbations relative to pre-transient flow conditions. Examples with pumps, valves, and actuators demonstrate the process of coupling equations for components at the ends of a line to obtain total system transfer functions and then obtain time domain solutions for outputs of interest associated with system inputs and load variations. Full article

(This article belongs to the Special Issue Advances in Fluid Power Systems and Actuators)

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32 pages, 51644 KB

Open AccessArticle

Fault Diagnosis of Planetary Gear Carrier Cracks Based on Vibration Signal Model and Modulation Signal Bispectrum for Actuation Systems

by Xiaosong Lin, Niaoqing Hu, Zhengyang Yin, Yi Yang, Zihao Deng and Zuanbo Zhou

Actuators 2025, 14(10), 488; https://doi.org/10.3390/act14100488 - 9 Oct 2025

Abstract

Planetary gearbox serves as a key transmission component in planetary ball screw actuator systems. Under the action of alternating loads, the stress concentration locations of the planet carrier in actuators with planetary gear trains are prone to fatigue cracks, which can lead to [...] Read more.

Planetary gearbox serves as a key transmission component in planetary ball screw actuator systems. Under the action of alternating loads, the stress concentration locations of the planet carrier in actuators with planetary gear trains are prone to fatigue cracks, which can lead to catastrophic system breakdowns. However, due to the complex vibration transmission path and the interference of uninterested vibration components, the characteristic modulation signal is ambiguous, so it is challenging to diagnose this fault. Therefore, this paper proposes a new fault diagnosis method. Firstly, a vibration signal model is established to accurately characterize the amplitude and phase modulation effects caused by cracked carriers, providing theoretical guidance for fault feature identification. Subsequently, three novel sideband evaluators of the modulation signal bispectrum (MSB) and their parameter selection ranges are proposed to efficiently locate the optimal fault-related bifrequency signatures and reduce computational cost, leveraging the effects identified by the model. Finally, a novel health indicator, the mean absolute root value (MARV), is used to monitor the state of the planet carrier. The effectiveness of this method is verified by experiments on the planetary gearbox test rig. The results show that the robustness of the amplitude and phase modulation effect of the cracked carrier in the low-frequency band is significantly higher than that in the high-frequency band, and the initial carrier crack can be accurately identified using this phenomenon under different operating conditions. This study provides a reliable solution for the condition monitoring and health management of the actuation system, which is helpful to improve the safety and reliability of operation. Full article

(This article belongs to the Special Issue Power Electronics and Actuators—Second Edition)

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25 pages, 7253 KB

Open AccessArticle

Dynamic Trajectory Planning for Automatic Grinding of Large-Curved Forgings Based on Adaptive Impedance Control Strategy

by Luping Luo, Kekang Qiu and Congchun Huang

Actuators 2025, 14(10), 487; https://doi.org/10.3390/act14100487 - 8 Oct 2025

Abstract

In this paper, we proposed a novel method for grinding trajectory planning on large-curved forgings to improve grinding performance and grinding efficiency. Our method consists of four main steps. Firstly, we conducted simulations and analyses on the contact state and contact pressure between [...] Read more.

In this paper, we proposed a novel method for grinding trajectory planning on large-curved forgings to improve grinding performance and grinding efficiency. Our method consists of four main steps. Firstly, we conducted simulations and analyses on the contact state and contact pressure between the grinding tool and curved workpieces, and explored different grinding methods. Based on the Preston equation, a material removal model was established to analyze the grinding force. Secondly, we proposed an adaptive impedance control method based on grinding force analysis, which can control the contact force indirectly by adjusting the end position of the robot. To address the inability of impedance control to adjust impedance parameters in real time, a control strategy involving online estimation of environmental position and stiffness is adopted. Based on the Lyapunov asymptotic stability principle, an adaptive impedance control model is established, and the effectiveness of the adaptive algorithm is verified through simulation. Thirdly, Position correction is realized through gravity compensation of the grinding force and discretization of the impedance control model. Subsequently, a dynamic trajectory adjustment strategy is proposed, which integrates position correction for the current grinding point and position compensation for the next grinding point, to achieve the force control objective in the grinding process. Finally, a constant force grinding experiment was conducted on large-curvature blades using a robotic automatic grinding system. The grinding system effectively removed the knife marks on the blade surface, resulting in a surface roughness of 0.5146 μm and a grinding efficiency of approximately 0.89 cm²/s. The simulation and experimental results indicate that the smoothness and grinding efficiency of the blades are superior to the enterprise’s existing grinding technology, verifying the feasibility and effectiveness of our proposed method. Full article

(This article belongs to the Section Control Systems)

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19 pages, 2433 KB

Open AccessArticle

Two-Dimensional Analytical Magnetic Field Calculation in a Brushless Doubly Fed Reluctance Machine

by Slimane Tahi, Cherif Guerroudj, Smail Mezani, Rachid Ibtiouen and Noureddine Takorabet

Actuators 2025, 14(10), 486; https://doi.org/10.3390/act14100486 - 7 Oct 2025

Abstract

This paper proposes a 2D semi-analytical model based on the subdomain method for the performance analysis of a brushless doubly fed reluctance machine (BDFRM) with a salient pole rotor. In particular, assuming an infinite magnetic permeability of the iron core and assuming a [...] Read more.

This paper proposes a 2D semi-analytical model based on the subdomain method for the performance analysis of a brushless doubly fed reluctance machine (BDFRM) with a salient pole rotor. In particular, assuming an infinite magnetic permeability of the iron core and assuming a smooth stator, the field calculation region is divided into two solution subdomains, i.e., the rotor slot and air-gap. The magnetic vector potential in each subdomain is obtained by solving the governing PDE by the separation of variables method and employing the boundary conditions between adjacent interfaces. Moreover, based on the stored magnetic energy in the air-gap, the calculation of the three-phase windings’ self and mutual inductances is presented. Through a case study involving a 6/2 pole BDFRM, the accuracy of the developed subdomain model is confirmed by comparing its analytically predicted results with those obtained from two-dimensional finite element method (FEM) simulations. Full article

(This article belongs to the Special Issue Advanced Theory and Application of Magnetic Actuators—3rd Edition)

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33 pages, 2954 KB

Open AccessReview

Classification Evolution, Control Strategy Innovation, and Future Challenges of Vehicle Suspension Systems: A Review

by Yixin Mei, Ruochen Wang, Renkai Ding and Yu Jiang

Actuators 2025, 14(10), 485; https://doi.org/10.3390/act14100485 - 6 Oct 2025

Abstract

The suspension system can adapt to different road excitations by adjusting its own stiffness or damping, or outputting active driving force, thereby improving the comprehensive dynamic performance of the vehicle, including ride comfort and vehicle handling. As the automotive industry’s requirements for “intelligence, [...] Read more.

The suspension system can adapt to different road excitations by adjusting its own stiffness or damping, or outputting active driving force, thereby improving the comprehensive dynamic performance of the vehicle, including ride comfort and vehicle handling. As the automotive industry’s requirements for “intelligence, comfort, and safety” continue to increase, the intelligence of suspension systems has become a research hotspot for scientific research institutions and enterprises, with broad development prospects. This article reviews the current development status of automotive suspensions and introduces the working principles and research status of different types of suspension systems, such as passive suspensions, semi-active suspensions, active suspensions, and electromagnetic suspensions. In addition, it summarizes the control methods of vehicle intelligent suspensions, including classical control, modern control, and intelligent control, and expounds the advantages and disadvantages of each control strategy. Finally, it summarizes the challenges and development trends faced by suspension systems. This review can provide technical reference for researchers engaged in the study of intelligent suspension under the modern chassis architecture and offer direction guidance for the development of key suspension technologies. Full article

(This article belongs to the Section Actuators for Surface Vehicles)

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24 pages, 10733 KB

Open AccessArticle

Sensorless Control of Linear Motion in a Linear-Rotary Reluctance Actuator Integrated into an Electromagnetic Dog Clutch

by Bogdan Miroschnitschenko

Actuators 2025, 14(10), 484; https://doi.org/10.3390/act14100484 - 4 Oct 2025

Abstract

A reluctance actuator integrated into the double-sided dog clutch of a gearbox can significantly simplify the gear shifting system. However, its disadvantage is that an axial position sensor is required to shift the neutral gear. The sensor is placed in the aggressive environment [...] Read more.

A reluctance actuator integrated into the double-sided dog clutch of a gearbox can significantly simplify the gear shifting system. However, its disadvantage is that an axial position sensor is required to shift the neutral gear. The sensor is placed in the aggressive environment of a gearbox and reduces the reliability of the entire system. Sensorless methods proposed in the literature deal with electrical machines or actuators with one degree of freedom (linear motion or rotation). In the dog clutch, the shift sleeve rotates and moves along its rotation axis simultaneously, moreover, the coil inductances are highly dependent not only on the axial position but also on the relative angular position between the shift sleeve teeth and the slots of its counterpart. This work proposes an original algorithm of sensorless control, which main novelty is the applicability for systems with two degrees of freedom, such as the considered actuator. The voltage induced in one of the coils and the prediction of the shift sleeve motion, which is based on the electromechanical model of the clutch, are used to control the currents. Not only an axial position sensor but also angular encoders are not required to apply the proposed method. The algorithm was tested both in simulations and experiments under different conditions. The results show that the proposed method allows to shift the neutral gear sensorless at different rotation speeds and different loads on the sleeve, regardless of what gearwheel is initially engaged. Full article

(This article belongs to the Section Control Systems)

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46 pages, 3841 KB

Open AccessSystematic Review

From Static to Adaptive: A Systematic Review of Smart Materials and 3D/4D Printing in the Evolution of Assistive Devices

by Muhammad Aziz Sarwar, Nicola Stampone and Muhammad Usman

Actuators 2025, 14(10), 483; https://doi.org/10.3390/act14100483 - 3 Oct 2025

Abstract

People with disabilities often face challenges like moving around independently and depending on personal caregivers for daily life activities. Traditional assistive devices are universally accepted by these communities, but they are designed with one-size-fits-all approaches that cannot adjust to individual human sizes, are [...] Read more.

People with disabilities often face challenges like moving around independently and depending on personal caregivers for daily life activities. Traditional assistive devices are universally accepted by these communities, but they are designed with one-size-fits-all approaches that cannot adjust to individual human sizes, are not easily customized, and are made from rigid materials that do not adapt as a person’s condition changes over time. This systematic review examines the integration of smart materials, sensors, actuators, and 3D/4D printing technologies in advancing assistive devices, with a particular emphasis on mobility aids. In this work, the authors conducted a comparative analysis of traditional devices with commercially available innovative prototypes and research stage assistive devices by focusing on smart adaptable materials and sustainable additive manufacturing techniques. The results demonstrate how artificial intelligence drives smart assistive devices in hospital decentralized additive manufacturing, and policy frameworks agree with the Sustainable Development Goals, representing the future direction for adaptive assistive technology. Also, by combining 3D/4D printing and AI, it is possible to produce adaptive, affordable, and patient centered rehabilitation with feedback and can also provide predictive and preventive healthcare strategies. The successful commercialization of adaptive assistive devices relies on cost effective manufacturing techniques clinically aligned development supported by cross disciplinary collaboration to ensure scalable, sustainable, and universally accessible smart solutions. Ultimately, it paves the way for smart, sustainable, and clinically viable assistive devices that outperform conventional solutions and promote equitable access for all users. Full article

(This article belongs to the Section Actuators for Robotics)

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18 pages, 4625 KB

Open AccessArticle

Design of Intersect Consequent Pole Rotor for a Radial-Flux IPMSM to Reduce Rare-Earth Magnet Usage

by Yun-Ha Song, Si-Woo Song, Do-Hyeon Choi, Su-Bin Jeon and Won-Ho Kim

Actuators 2025, 14(10), 482; https://doi.org/10.3390/act14100482 - 3 Oct 2025

Abstract

Interior Permanent Magnet Synchronous Motors (IPMSMs) are widely used in the electrification sector; however, reliance on rare-earth magnets imposes constraints stemming from supply instability and mining-related environmental impacts, raising sustainability concerns. To address these issues, this study investigates an IPMSM employing a consequent [...] Read more.

Interior Permanent Magnet Synchronous Motors (IPMSMs) are widely used in the electrification sector; however, reliance on rare-earth magnets imposes constraints stemming from supply instability and mining-related environmental impacts, raising sustainability concerns. To address these issues, this study investigates an IPMSM employing a consequent pole (CP) structure, in which one permanent magnet pole is replaced by iron. Because flux asymmetry in CP IPMSMs can cause torque ripple and associated vibration and noise, we propose an Intersect Consequent Pole (ICP) rotor geometry and evaluate it against a conventional IPMSM under identical stator conditions. The proposed ICP topology reduces permanent magnet usage and provides a rare-earth-reduced design alternative that addresses the vibration/noise trade-off, with a particular focus on electric power steering (EPS) applications. Electromagnetic characteristics and performance were analyzed using finite element analysis (FEA) and verified via FEA-based comparisons. Full article

(This article belongs to the Section High Torque/Power Density Actuators)

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