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Volume 14
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Actuators, Volume 14, Issue 9 (September 2025) – 40 articles

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27 pages, 12457 KB  
Article
Research on Dual-Motor Redundant Compensation for Unstable Fluid Load of Control Valves
by Zhisheng Li, Yudong Xie, Jiazhen Han and Yong Wang
Actuators 2025, 14(9), 452; https://doi.org/10.3390/act14090452 - 15 Sep 2025
Abstract
Control valves are widely applied in nuclear power, offshore oil/gas extraction, and chemical engineering, but suffer from issues like pressure oscillation, flow control accuracy degradation, and motor overload due to unstable fluid loads (e.g., nuclear reactions in power plants and complex marine climates). [...] Read more.
Control valves are widely applied in nuclear power, offshore oil/gas extraction, and chemical engineering, but suffer from issues like pressure oscillation, flow control accuracy degradation, and motor overload due to unstable fluid loads (e.g., nuclear reactions in power plants and complex marine climates). This paper proposes a dual-motor redundant compensation method to address these challenges. The core lies in a control strategy where a single main motor drives the valve under normal conditions, while a redundant motor intervenes when load torque exceeds a preset threshold—calculated via the valve core’s fluid load model. By introducing excess load torque as positive feedback to the current loop, the method coordinates torque output between the two motors. AMESim and Matlab/Simulink joint simulations compare single-motor non-compensation, single-motor compensation, and dual-motor schemes. Results show that under inlet pressure step changes, the dual-motor compensation scheme shortens the stabilization time of the valve’s controlled variable by 40%, reduces overshoot by 65%, and decreases motor torque fluctuation by 50%. This redundant design enhances fault tolerance, providing a novel approach for reliability enhancement of deep-sea oil/gas control valves. Full article
(This article belongs to the Section Control Systems)
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25 pages, 1260 KB  
Article
Fully-Distributed Bipartite Consensus for Linear Multiagent Systems with Dynamic Event-Triggered Mechanism Under Signed Topology Network
by Han Sun, Xiaogong Lin and Dawei Zhao
Actuators 2025, 14(9), 451; https://doi.org/10.3390/act14090451 - 13 Sep 2025
Viewed by 38
Abstract
This article investigates the bipartite consensus control problem of general linear multiagent systems over an antagonistic interaction topology using a dynamic event-triggered mechanism. Primarily, for each agent, a distributed dynamic event-triggered control scheme is proposed based on a signed cooperative–competitive communication graph. Controller [...] Read more.
This article investigates the bipartite consensus control problem of general linear multiagent systems over an antagonistic interaction topology using a dynamic event-triggered mechanism. Primarily, for each agent, a distributed dynamic event-triggered control scheme is proposed based on a signed cooperative–competitive communication graph. Controller updates and triggering condition monitoring are executed only when a specified event is triggered, thereby reducing communication overhead. Subsequently, by integrating the time-varying control gain into the presented control strategy, a fully distributed bipartite controller architecture is defined without using global topology information. As a result, the influence of coupling weights on each agent can be restrained, enabling the realization of bipartite consensus for multiagent systems. Moreover, the proposed dynamic event-triggered control protocol is rigorously proven to exclude Zeno behavior over the entire time horizon. Finally, numerical simulations are presented to demonstrate the effectiveness of the proposed method. Full article
(This article belongs to the Special Issue Advanced Technologies in Actuators for Control Systems)
19 pages, 4083 KB  
Article
Design and Analysis of a Dual-Screw Propelled Robot for Underwater and Muddy Substrate Operations in Agricultural Ponds
by Yan Xu, Pengchao Dai, Mingjin Xin, Liyan Wu and Yuqiu Song
Actuators 2025, 14(9), 450; https://doi.org/10.3390/act14090450 - 12 Sep 2025
Viewed by 170
Abstract
Conventional underwater vehicles, which are typically equipped with oscillating fins or standard propellers, are incapable of effective locomotion within the viscous, high-resistance environment of muddy substrates common in agricultural ponds. To address this operational limitation, this paper presents a compact dual-screw propelled robot [...] Read more.
Conventional underwater vehicles, which are typically equipped with oscillating fins or standard propellers, are incapable of effective locomotion within the viscous, high-resistance environment of muddy substrates common in agricultural ponds. To address this operational limitation, this paper presents a compact dual-screw propelled robot capable of traversing both the water column and soft substrate layers. The robot’s locomotion is driven by two optimized helical screw propellers, while depth control and roll stability are actively managed by a control fin. A dynamic model of the robot–fluid interaction was developed to optimize the screw configuration that achieves a maximum theoretical thrust of 40 N with a calculated 16% slippage rate in mud. Computational fluid dynamics simulations were employed to determine the optimal angle for the control fin, which was found to be 9°, maximizing the lift-to-drag ratio at 12.09 for efficient depth maneuvering. A cable-free remote control system with a response time of less than 0.5 s governs all operations. Experimental validation in a controlled tank environment confirmed the robot’s performance, demonstrating stable locomotion at 0.4 m/s in water and 0.3 m/s in a simulated mud substrate. This dual-screw propelled robot represents a promising technological solution for comprehensive monitoring and operational tasks in agricultural pond environments. Full article
(This article belongs to the Special Issue Design and Control of Agricultural Robotics)
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21 pages, 12614 KB  
Article
Research on Inertial Force Suppression Control for Hydraulic Cylinder Synchronization of Shield Tunnel Segment Erector Based on Sliding Mode Control
by Fangao Zhang, Zhaoqiang Wang, Xiaori Zhang, Xiaoqiang Wang and Xiaoxi Hu
Actuators 2025, 14(9), 449; https://doi.org/10.3390/act14090449 - 11 Sep 2025
Viewed by 165
Abstract
As a critical component in tunnel construction, the segment erector of shield tunneling machines critically influences segment assembly quality and construction efficiency, largely determined by its dual-cylinder synchronization control. Addressing challenges such as dynamic coupling, nonlinear disturbances, and significant inertial force fluctuations inherent [...] Read more.
As a critical component in tunnel construction, the segment erector of shield tunneling machines critically influences segment assembly quality and construction efficiency, largely determined by its dual-cylinder synchronization control. Addressing challenges such as dynamic coupling, nonlinear disturbances, and significant inertial force fluctuations inherent in hydraulic cylinder synchronization under large-inertia loads and variable working conditions, this study proposes an optimized inertial force suppression strategy utilizing an improved sliding mode control (SMC). Mechanical and hydraulic dynamic models of the dual-cylinder lifting mechanism were established to analyze load distribution and force-arm variation patterns, thereby elucidating the influence of inertial forces on synchronization accuracy. Based on this analysis, an adaptive boundary-layer SMC, incorporating real-time inertial force compensation, was designed. This design effectively suppresses system chattering and enhances robustness. Simulation and experimental results demonstrate that the proposed method achieves synchronization errors within ±0.5 mm during step responses, reduces inertial force peaks by 50%, and exhibits significantly superior anti-interference performance compared to conventional PID control. This research provides theoretical foundations and practical engineering insights for high-precision synchronization control in shield tunneling, demonstrating substantial application value. Full article
(This article belongs to the Section Control Systems)
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24 pages, 840 KB  
Article
Adaptive Event-Triggered Full-State Constrained Control of Multi-Agent Systems Under Cyber Attacks
by Jinxia Wu, Pengfei Cui, Juan Wang and Yuanxin Li
Actuators 2025, 14(9), 448; https://doi.org/10.3390/act14090448 - 11 Sep 2025
Viewed by 90
Abstract
For multi-agent systems under Denial-of-Service (DoS) attacks, a relative threshold strategy for event triggering and a state-constrained control method with prescribed performance are proposed. Within the framework of combining graph theory with the leader–follower approach, coordinate transformation is utilized to decouple the multi-agent [...] Read more.
For multi-agent systems under Denial-of-Service (DoS) attacks, a relative threshold strategy for event triggering and a state-constrained control method with prescribed performance are proposed. Within the framework of combining graph theory with the leader–follower approach, coordinate transformation is utilized to decouple the multi-agent system. Inspired by the three-way handshake technology of TCP communication, a DoS detection system is designed based on event-triggering. This system is used to detect DoS attacks, prevent the impacts brought by DoS attacks, and reduce the update frequency of the controller. Fuzzy logic systems are employed to approximate the unknown nonlinear functions within the system. By using a first-order filter to approximate the derivative of the virtual controller, the computational complexity issue in the backstepping method is addressed. Furthermore, The Barrier Lyapunov Function (BLF) possesses unique mathematical properties. When the system state approaches the pre-set boundary, it can exhibit a special variation trend, thereby imposing a restrictive effect on the system state. The Prescribed Performance Function (PPF), on the other hand, defines the expected performance standards that the system aims to achieve in the tracking task, covering key indicators such as tracking accuracy and response speed. By organically integrating these two functions, the system can continuously monitor and adjust its own state during operation. When there is a tendency for the tracking error to deviate from the specified range, the combined function mechanism will promptly come into play. Through the reasonable adjustment of the system’s control input, it ensures that the tracking error always remains within the pre-specified range. Finally, through Lyapunov analysis, the proposed control protocol ensures that all closed-loop signals remain bounded under attacks, with the outputs of all followers synchronizing with the leader’s output in the communication graph. Full article
(This article belongs to the Special Issue Advanced Technologies in Actuators for Control Systems)
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38 pages, 5009 KB  
Article
An Adaptive Estimation Model for the States and Loads in Electro-Hydraulic Actuation Systems
by Dimitar Dichev, Borislav Georgiev, Iliya Zhelezarov, Tsanko Karadzhov and Hristo Hristov
Actuators 2025, 14(9), 447; https://doi.org/10.3390/act14090447 - 11 Sep 2025
Viewed by 76
Abstract
In this study, we introduce an advanced framework for state estimation in electro-hydraulic systems, utilizing a structurally adapted Kalman filter. The proposed model was designed to enhance estimation accuracy and robustness under dynamic load variations and evolving measurement conditions. A notable feature of [...] Read more.
In this study, we introduce an advanced framework for state estimation in electro-hydraulic systems, utilizing a structurally adapted Kalman filter. The proposed model was designed to enhance estimation accuracy and robustness under dynamic load variations and evolving measurement conditions. A notable feature of the approach is the algebraic resolution of one system state during each iteration, enabling the seamless inclusion of variables that are otherwise difficult to measure, without disrupting the model’s linear formulation. In addition, the dynamics of the load torque are empirically characterized through a regression-based model derived from experimental observations. The framework integrates adaptive mechanisms for updating the model and measurement error covariance matrices, facilitating the real-time accommodation of system nonlinearities and environmental changes. Experimental results are presented in different operating modes, reflecting characteristic dynamic movements. They show that the method reduced the root mean square error (RMSE) when estimating angular velocity between five and more than six times, depending on the mode. When evaluating the load torque, even in modes with a sharply changing load, the RMSE value remains stable below 0.05 Nm, which indicates the absence of systematic drift and high stability of the estimates. This confirms the stable operation of the algorithm in dynamic conditions and its applicability in real systems. Full article
(This article belongs to the Section Control Systems)
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14 pages, 1256 KB  
Article
Application-Oriented Analysis of Hexaglide Pose Accuracy in Through-Hole Assembly of Electronic Components
by Mikhail Polikarpov, Yousuf Mehmood and Jochen Deuse
Actuators 2025, 14(9), 446; https://doi.org/10.3390/act14090446 - 9 Sep 2025
Viewed by 179
Abstract
Hexaglide parallel manipulators are characterized by high accuracy and dynamic performance, which makes them suitable for industrial high-precision assembly tasks such as placement of electronic THT components on printed circuit boards. In this paper we describe an assembly system that comprises a Hexaglide [...] Read more.
Hexaglide parallel manipulators are characterized by high accuracy and dynamic performance, which makes them suitable for industrial high-precision assembly tasks such as placement of electronic THT components on printed circuit boards. In this paper we describe an assembly system that comprises a Hexaglide manipulator with vertical ball screws, moving printed circuit boards relative to stationary THT components. We evaluate the effects of the manufacturing tolerances of machine parts, such as bar length tolerance, ball screw axis position uncertainty, and ball screw axis orientation uncertainty, on Hexaglide end-effector pose accuracy using a geometric simulation study based on stochastic tolerance sampling. In the investigated configuration and under standard industrial tolerances, bar length inaccuracy and axis position uncertainty lead to significant position and rotation deviations for the Hexaglide end-effector in the horizontal plane that need to be compensated for by control algorithms to enable THT assembly using the Hexaglide prototype. The geometric simulation method applied in this paper can be used by designers of Hexaglide machines to study and evaluate different machine configurations. Full article
(This article belongs to the Special Issue Industrial and Biomechanical Applications of Actuators and Robots and Eco-Sustainability)
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17 pages, 3584 KB  
Article
Developing an Energy-Efficient Electrostatic-Actuated Micro-Accelerometer for Low-Frequency Sensing Applications
by Umar Jamil, Muhammad Sohaib Zahid, Nouman Ghafoor, Faisal Nawaz, Jose Raul Montes-Bojorquez and Mehboob Alam
Actuators 2025, 14(9), 445; https://doi.org/10.3390/act14090445 - 8 Sep 2025
Viewed by 223
Abstract
Micro-accelerometers are in high demand across many due to their compact size, low energy consumption, and excellent precision. Since gravity causes a large movement when the device is positioned vertically, measuring low gravitational acceleration is challenging. This study examines the intrinsic relationship between [...] Read more.
Micro-accelerometers are in high demand across many due to their compact size, low energy consumption, and excellent precision. Since gravity causes a large movement when the device is positioned vertically, measuring low gravitational acceleration is challenging. This study examines the intrinsic relationship between applied voltage levels and displacement in micro-accelerometers. The study introduces a novel design that integrates hybrid flexures, comprising both linear and angular configurations, with an out-of-plane overlap varying (OPOV) electrostatic actuation mechanism. This design aims to measure the micro-accelerometer’s movement and low frequency response. The proposed device with silicon material is designed and simulated using the IntelliSuite® software, considering its small dimensions and 25 µm thickness. The norm value of 28.0916 μN from gravity’s reaction forces on the body, a resonant frequency of 179.668 Hz at the first desired mode, and a maximum stress of 24.7 MPa were obtained through the electro-mechanical analysis. A comparison of the proposed design was conducted with other configurations, measuring a frequency of 179.668 Hz at a minimum downward displacement of 7.69916 µm under the influence of gravity without electrostatic mechanisms. Following this, an electrostatic actuation mechanism was introduced to minimize displacement by applying different voltage levels, including 1 V, 1.5 V, and 3 V. At 3 V, a significant improvement in displacement reduction was observed compared to the other applied voltages. Additionally, dynamic and sensitivity analyses were carried out to validate the performance of the proposed design further. Full article
(This article belongs to the Special Issue Recent Advances in the Design and Applications for Magnetoelastic and Electroelastic Actuators)
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14 pages, 2638 KB  
Article
The Impact of Pump Cavity Gaps on the Flow Characteristics of Helical Mixed-Flow Pumps
by Wei Han, Yucheng Chen, Tongqing Xue and Pengzheng Lei
Actuators 2025, 14(9), 444; https://doi.org/10.3390/act14090444 - 8 Sep 2025
Viewed by 223
Abstract
The performance of pump-jet propulsion systems is critically important in defense and marine applications. However, their optimization has encountered bottlenecks due to a lack of theoretical understanding of underlying flow mechanisms. This study investigates the influence of the pump cavity gap on the [...] Read more.
The performance of pump-jet propulsion systems is critically important in defense and marine applications. However, their optimization has encountered bottlenecks due to a lack of theoretical understanding of underlying flow mechanisms. This study investigates the influence of the pump cavity gap on the flow characteristics and performance of a helical mixed-flow pump using numerical simulations. The gap size is non-dimensionalized as a gap coefficient—defined as the ratio of pump cavity gap to blade thickness—with the inlet ring gap fixed at 0.2 mm. Results demonstrate that the gap coefficient significantly affects internal flow stability and energy loss. A gap coefficient of 0.15 effectively suppresses leakage and vortex formation, improving efficiency (peak efficiency reaches 75%) and head (1.9 m) under low-flow conditions. This configuration also promotes uniform pressure distribution on the impeller shaft surface and reduces turbulent kinetic energy and axial vorticity. In contrast, a smaller gap coefficient (0.125) exacerbates flow separation at high flow rates, while a larger value (0.2) increases leakage losses and degrades performance. The study elucidates correlations between the pump cavity gap and vortex evolution, pressure gradient, and turbulence distribution, providing theoretical support for the optimized design of helical mixed-flow pumps. Full article
(This article belongs to the Special Issue Advanced Actuators and Magnetic Fluid Systems: Design, Control, and Applications)
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19 pages, 1539 KB  
Article
Design and Evaluation of a Torque-Controlled Ankle Exoskeleton Using the Small-Scale Hydrostatic Actuator: miniHydrA
by Kyrian Staman and Herman van der Kooij
Actuators 2025, 14(9), 443; https://doi.org/10.3390/act14090443 - 8 Sep 2025
Viewed by 265
Abstract
A small-scale electro-hydrostatic actuator, termed miniHydrA, was developed based on biomechanical requirements for gait and integrated into an ankle exoskeleton. The key advantage of this actuator concept lies in its compact size and the low mass of its output stage, combined with the [...] Read more.
A small-scale electro-hydrostatic actuator, termed miniHydrA, was developed based on biomechanical requirements for gait and integrated into an ankle exoskeleton. The key advantage of this actuator concept lies in its compact size and the low mass of its output stage, combined with the ability to deliver high support torques, sufficient for full human assistance. During development, hydraulic cylinder leakage and friction were identified as key challenges. To address control requirements, a dedicated control strategy was proposed and implemented. The prototype exoskeleton was evaluated for joint torque tracking performance across a range of torques (0–120 Nm), both in benchtop tests and during treadmill walking trials. In benchtop experiments, zero-torque tracking was achieved with a mean absolute error ranging from 0.03 to 2.26 Nm across frequencies from 0 to 5 Hz. During treadmill walking, torque tracking errors ranged from 0.70 to 0.95 Nm, with no observable deviations in ankle joint kinematics among the three test subjects. These results show the feasibility of the miniHydrA for remote actuation. Compared to Bowden cables, commonly used in exoskeletons and exosuits, the proposed actuator concept offers two key advantages: it is better suited for high-torque applications, and its friction characteristics can be more accurately predicted and modeled, enabling more effective feedforward control. Full article
(This article belongs to the Special Issue Control of Hydraulic Robotic Manipulators)
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23 pages, 4098 KB  
Article
Modeling of the Dynamic Characteristics for a High-Load Magnetorheological Fluid-Elastomer Isolator
by Yu Tao, Wenhao Chen, Feifei Liu and Ruijie Han
Actuators 2025, 14(9), 442; https://doi.org/10.3390/act14090442 - 5 Sep 2025
Viewed by 169
Abstract
To meet the vibration isolation requirements of engines under diverse operating conditions, this paper proposes a novel magnetorheological fluid-elastomer isolator with high load and tunable parameters. The mechanical and magnetic circuit structures of the isolator were designed and optimized through theoretical calculations and [...] Read more.
To meet the vibration isolation requirements of engines under diverse operating conditions, this paper proposes a novel magnetorheological fluid-elastomer isolator with high load and tunable parameters. The mechanical and magnetic circuit structures of the isolator were designed and optimized through theoretical calculations and finite element simulations, achieving effective vibration isolation within confined spaces. The dynamic performance of the isolator was experimentally evaluated using a hydraulic testing system under varying excitation amplitudes, frequencies, initial positions, and magnetic fields. Experimental results indicate that the isolator achieves a static stiffness of 3 × 106 N/m and a maximum adjustable compression load range of 105.4%. In light of the asymmetric nonlinear dynamic behavior of the isolator, an improved nine-parameter Bouc–Wen model is proposed. Parameter identification performed via a genetic algorithm demonstrates a model accuracy of 95.0%, with a minimum error reduction of 28.8% compared to the conventional Bouc–Wen model. Full article
(This article belongs to the Section Precision Actuators)
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23 pages, 3539 KB  
Article
Synchronous Leveling Control Method of Crane Vehicle Platform Based on Position–Force Coordination
by Feixiang Xu, Haichao Hu, Shiyong Feng and Chen Zhou
Actuators 2025, 14(9), 441; https://doi.org/10.3390/act14090441 - 5 Sep 2025
Viewed by 198
Abstract
Leveling of the crane support platform plays a vital role in operational safety and lifting efficiency; it requires both precise horizontal positioning and the rational distribution of outrigger load. However, the current synchronous leveling methods mainly focus on displacement synchronization leveling while neglecting [...] Read more.
Leveling of the crane support platform plays a vital role in operational safety and lifting efficiency; it requires both precise horizontal positioning and the rational distribution of outrigger load. However, the current synchronous leveling methods mainly focus on displacement synchronization leveling while neglecting the control of outrigger load, resulting in the problem of individual outrigger overloading. To address this problem, a synchronous leveling control method with variable load constraints (SLCM-VLC) is proposed in this paper based on the framework of model predictive control. Firstly, the proposed method conducts independent outrigger modeling and decoupling of outriggers through adjacent cross-coupling; then a displacement synchronization controller (DSC) is designed to ensure efficient synchronous leveling. Secondly, a collaborative controller of displacement and force (DFCC) under variable load constraints is designed to overcome the limitations of traditional independent optimization. Subsequently, an extended state observer (ESO) is introduced to compensate for environmental disturbances and control deviations. Finally, the effectiveness of the proposed method is verified through a co-simulation using Matlab, Adams, and Solidworks. The results show that, compared with existing leveling control methods, the proposed method can achieve high precision and rapid leveling under smaller peak load, thereby extending the service life of the platform’s electric cylinders. Full article
(This article belongs to the Section Control Systems)
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16 pages, 2759 KB  
Article
Research on Linear Active Disturbance Rejection Control of Electrically Excited Motor for Vehicle Based on ADP Parameter Optimization
by Heping Ling, Junzhi Zhang and Hua Pan
Actuators 2025, 14(9), 440; https://doi.org/10.3390/act14090440 - 4 Sep 2025
Viewed by 209
Abstract
In the three-motor hybrid architecture, the auxiliary drive uses electrically excited synchronous motor (EESM), which has the advantages of high torque density, wide speed range and strong anti-demagnetization ability. However, the strong electromagnetic coupling between the field winding and the armature winding leads [...] Read more.
In the three-motor hybrid architecture, the auxiliary drive uses electrically excited synchronous motor (EESM), which has the advantages of high torque density, wide speed range and strong anti-demagnetization ability. However, the strong electromagnetic coupling between the field winding and the armature winding leads to the difficulty of current control, and the traditional PID has limitations in dynamic response and immunity. In order to solve this problem, a linear active disturbance rejection control (LADRC) method for the rotor of EESM is proposed in this paper, linear extended state observer (LESO) is used to estimate and compensate the system internal and external disturbances (such as winding coupling and parameter perturbation) in real time. The method only uses the input and output of the system and does not depend on any mechanical parameters, so that the torque response is improved by 50%, and the steady-state fluctuation is reduced by 10.2%. In addition, an adaptive dynamic programming (ADP) parameter optimization strategy is proposed to solve the bandwidth parameter tuning problem of LADRC algorithm in complex operating conditions, and the related mathematical analysis of optimality properties is given. Finally, the proposed method is compared with the traditional PI controller in several operating conditions of EESM, and the effectiveness of the proposed method is validated by the corresponding results. Full article
(This article belongs to the Section Control Systems)
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20 pages, 5464 KB  
Article
Simulation-Based Testing of Autonomous Robotic Systems for Surgical Applications
by Jun Lin, Tiantian Sun, Rihui Song, Di Zhu, Lan Liu, Jiewu Leng, Kai Huang and Rongjie Yan
Actuators 2025, 14(9), 439; https://doi.org/10.3390/act14090439 - 4 Sep 2025
Viewed by 332
Abstract
Autonomous surgery involves surgical tasks performed by a robot with minimal or no human involvement. Thanks to its precise automation, surgical robotics offers significant benefits in enhancing the consistency, safety, and quality of procedures, driving its growing popularity. However, ensuring the safety of [...] Read more.
Autonomous surgery involves surgical tasks performed by a robot with minimal or no human involvement. Thanks to its precise automation, surgical robotics offers significant benefits in enhancing the consistency, safety, and quality of procedures, driving its growing popularity. However, ensuring the safety of autonomous surgical robotic systems remains a significant challenge. To address this, we propose a simulation-based validation method to detect potential safety issues in the software of surgical robotic systems, complemented by a digital twin to estimate the gap between simulation and reality. The validation framework consists of a test case generator and a monitor for validating properties and evaluating the performance of the robotic system during test execution. Using a robotic arm for needle insertion as a case study, we present a systematic test case generation method that ensures effective coverage measurement for a three-dimensional, irregular model. Since no simulation can perfectly replicate reality due to differences in sensing and actuation, the digital twin bridges the gap between simulation and the physical robotic arm. This integration enables us to assess the discrepancy between virtual simulations and real-world operations by verifying whether the data from the simulation accurately predicts real-world outcomes. Through extensive experimentation, we identified several flaws in the robotic software. Co-simulation within the digital twin framework has highlighted these discrepancies that should be considered. Full article
(This article belongs to the Section Actuators for Robotics)
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15 pages, 1796 KB  
Article
Second- and Third-Order Stability Bounds for High-Order Linear Consensus on Directed Graph Topologies with Partial Relative State Information and Global/Local Gains
by Eric A. Butcher and Mohammad Maadani
Actuators 2025, 14(9), 438; https://doi.org/10.3390/act14090438 - 3 Sep 2025
Viewed by 242
Abstract
A general high-order linear consensus protocol is proposed for coupling topologies defined by directed graphs with partial relative state information and a reference model with lobal/local gains. Necessary and sufficient second-order stability bounds for the cases of relative position feedback with reference velocity [...] Read more.
A general high-order linear consensus protocol is proposed for coupling topologies defined by directed graphs with partial relative state information and a reference model with lobal/local gains. Necessary and sufficient second-order stability bounds for the cases of relative position feedback with reference velocity and relative position and velocity feedback are then reviewed. Next, new necessary and sufficient stability bounds are obtained for third-order consensus for three cases of feedback of full and partial relative state information. The stability bounds obtained, unlike in prior studies, allow for the gains to be conveniently selected in a sequential manner and are shown to utilize those for second-order consensus. Comparisons with conservative stability bounds from previous studies are shown, and illustrative examples of the proposed consensus protocols and the obtained stability bounds are provided. Full article
(This article belongs to the Special Issue New Control Schemes for Actuators—2nd Edition)
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28 pages, 2429 KB  
Article
Neural Network Disturbance Observer-Based Adaptive Fault-Tolerant Attitude Tracking Control for UAVs with Actuator Faults, Input Saturation, and External Disturbances
by Yan Zhou, Ye Liu, Jiaze Li and Huiying Liu
Actuators 2025, 14(9), 437; https://doi.org/10.3390/act14090437 - 3 Sep 2025
Viewed by 228
Abstract
A dual-loop fault-tolerant control scheme is investigated for UAV attitude control systems subject to actuator faults, input saturation, and external disturbances in this paper. In the outer loop of attitude angles, a nonlinear dynamic inversion controller is developed as baseline controller for fast [...] Read more.
A dual-loop fault-tolerant control scheme is investigated for UAV attitude control systems subject to actuator faults, input saturation, and external disturbances in this paper. In the outer loop of attitude angles, a nonlinear dynamic inversion controller is developed as baseline controller for fast response and is augmented by a neural network disturbance observer to enhance the adaptability and robustness. Considering input saturation, actuator faults, and external disturbances in the inner loop of attitude angle velocities, the unbalanced input saturation is first converted into a time-varying system with unknown parameters and disturbances using a nonlinear function approximation method. An L1 adaptive fault-tolerant controller is then introduced to compensate for the effects of lumped uncertainties including system uncertainties, actuator faults, external disturbances, and approximation errors, and the stability and performance boundaries are verified by Lyapunov theorem and L1 reference system. Some simulation examples are carried out to demonstrate its effectiveness. Full article
(This article belongs to the Section Control Systems)
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11 pages, 1251 KB  
Article
AI-Enhanced Model for Integrated Performance Prediction and Classification of Vibration-Reducing Gloves for Hand-Transmitted Vibration Control
by Yumeng Yao, Wei Xiao, Alireza Moezi, Marco Tarabini, Paola Saccomandi and Subhash Rakheja
Actuators 2025, 14(9), 436; https://doi.org/10.3390/act14090436 - 3 Sep 2025
Viewed by 316
Abstract
This study presents a human-centric, data-driven modeling framework for the intelligent evaluation and classification of vibration-reducing (VR) gloves used in hand-transmitted vibration environments. Recognizing the trade-offs between protection and functionality, the integrated performance assessment incorporates three critical and often conflicting metrics: manual dexterity, [...] Read more.
This study presents a human-centric, data-driven modeling framework for the intelligent evaluation and classification of vibration-reducing (VR) gloves used in hand-transmitted vibration environments. Recognizing the trade-offs between protection and functionality, the integrated performance assessment incorporates three critical and often conflicting metrics: manual dexterity, grip strength, and distributed vibration transmissibility at the palm and fingers. Three independent experiments involving fifteen participants were conducted to evaluate the individual performance of ten commercially available VR gloves fabricated from air bladders, polymers, and viscoelastic gels. The effects of VR gloves on manual dexterity, grip strength, and distributed vibration transmission were investigated. The resulting experimental data were used to train and tune seven different machine learning models. The results suggested that the AdaBoost model demonstrated superior predictive performance, achieving 92% accuracy in efficiently evaluating the integrated performance of VR gloves. It is further shown that the proposed data-driven model could be effectively applied to classify the performances of VR gloves in three workplace conditions based on the dominant vibration frequencies (low-, medium-, and high-frequency). The proposed framework demonstrates the potential of AI-enhanced intelligent actuation systems to support personalized selection of wearable protective equipment, thereby enhancing occupational safety, usability, and task efficiency in vibration-intensive environments. Full article
(This article belongs to the Special Issue Human-Centric Intelligent Actuation Systems: Innovations in Control, Sensing, and Multidisciplinary Applications)
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24 pages, 1435 KB  
Article
Robust Sliding Mode Motion Control for an Integrated Hydromechatronic Actuator
by Dom Wilson, Andrew Plummer and Ioannis Georgilas
Actuators 2025, 14(9), 435; https://doi.org/10.3390/act14090435 - 3 Sep 2025
Viewed by 223
Abstract
Electro-hydraulic servoactuators have great potential in mobile robotics due to their robustness, high bandwidth and power density, but compared with electromechanical actuators, they can be inefficient and more difficult to integrate into systems. The Integrated Smart Actuator (ISA) developed by Moog Controls Ltd. [...] Read more.
Electro-hydraulic servoactuators have great potential in mobile robotics due to their robustness, high bandwidth and power density, but compared with electromechanical actuators, they can be inefficient and more difficult to integrate into systems. The Integrated Smart Actuator (ISA) developed by Moog Controls Ltd. is a hydromechatronic device that aims to address these issues by combining a novel efficient servovalve, cylinder, sensors and control electronics into a single component. The aim of this work was to develop a robust motion control algorithm that can make integration of the ISA into a robotic system straightforward by requiring minimal controller set-up despite variations in the load characteristics. The proposed controller is a sliding mode controller with a varying boundary layer that contains two robustness parameters and a single bandwidth parameter that defines the response. The controller outperforms a conventional high-performance linear controller in terms of tracking performance and its robustness to variations in the load mass and fluid bulk modulus. The response when the system was subject to some unachievable demand trajectories, such as large step demands, was found to be poor, and an online velocity, acceleration and jerk limited trajectory filter was demonstrated to rectify this issue. The successful implementation of a robust motion controller enables this highly novel integrated actuator to live up to its ‘smart’ epithet. Full article
(This article belongs to the Special Issue Intelligent and Precision Control for Mechatronic/Electro-Hydraulic Systems—Second Edition)
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30 pages, 2358 KB  
Article
Model-Based Reinforcement Learning for Containing Malware Propagation in Wireless Radar Sensor Networks
by Haitao Lin, Can Tian, Linman Chen, Daizhi Liao, Yunbo Wang and Yubo Hua
Actuators 2025, 14(9), 434; https://doi.org/10.3390/act14090434 - 2 Sep 2025
Viewed by 270
Abstract
To address malware containment challenges in WRSNs—where traditional integer-order models neglect propagation memory effects and standard reinforcement learning (RL) suffers from slow trial-and-error limitations—we propose the following: (1) a fractional-order VCISQ epidemic model capturing temporal dependencies for higher accuracy, and (2) a model-based [...] Read more.
To address malware containment challenges in WRSNs—where traditional integer-order models neglect propagation memory effects and standard reinforcement learning (RL) suffers from slow trial-and-error limitations—we propose the following: (1) a fractional-order VCISQ epidemic model capturing temporal dependencies for higher accuracy, and (2) a model-based Soft Actor–Critic (MBSAC) method, which integrates a learned transition model into an actor–critic architecture to predict future states from limited data, accelerating learning. Experiments confirm MBSAC outperforms RL baselines by reducing control overhead, hastening convergence, and enhancing robustness. It alleviates the rigidity of the traditional method and establishes a reward-driven safeguard for WRSNs. Full article
(This article belongs to the Special Issue Intelligent Sensing, Control and Actuation in Networked Systems)
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18 pages, 3794 KB  
Article
Augmented Recursive Sliding Mode Observer Based Adaptive Terminal Sliding Mode Controller for PMSM Drives
by Qiankang Hou, Bin Ma, Yan Sun, Bing Shi and Chen Ding
Actuators 2025, 14(9), 433; https://doi.org/10.3390/act14090433 - 2 Sep 2025
Viewed by 232
Abstract
Time-varying lumped disturbance and measurement noise are primary obstacles that restrict the control performance of permanent magnet synchronous motor (PMSM) drives. To tackle these obstacles, an adaptive nonsingular terminal sliding mode (ANTSM) algorithm is combined with augmented recursive sliding mode observer (ARSMO) for [...] Read more.
Time-varying lumped disturbance and measurement noise are primary obstacles that restrict the control performance of permanent magnet synchronous motor (PMSM) drives. To tackle these obstacles, an adaptive nonsingular terminal sliding mode (ANTSM) algorithm is combined with augmented recursive sliding mode observer (ARSMO) for PMSM speed regulation system in this paper. Generally, conventional nonsingular terminal sliding mode (NTSM) controller adopts a fixed and conservative control gain to suppress the time-varying disturbance, which will lead to unsatisfactory steady-state performance. Without requiring any information of the time-varying disturbance in advance, a novel barrier function adaptive algorithm is utilized to adjust the gain of NTSM controller online according to the amplitude of disturbance. In addition, the ARSMO is emoloyed to estimate the total disturbance and motor speed simultaneously, thereby alleviating the negative impact of measurement noise and excessive control gain. Comprehensive experimental results verify that the proposed enhanced ANTSM strategy can optimize the dynamic performance of PMSM system without sacrificing its steady-state performance. Full article
(This article belongs to the Section Control Systems)
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16 pages, 11849 KB  
Article
A Modular Soft Gripper with Embedded Force Sensing and an Iris-Type Cutting Mechanism for Harvesting Medium-Sized Crops
by Eduardo Navas, Kai Blanco, Daniel Rodríguez-Nieto and Roemi Fernández
Actuators 2025, 14(9), 432; https://doi.org/10.3390/act14090432 - 2 Sep 2025
Viewed by 501
Abstract
Agriculture is facing increasing challenges due to labor shortages, rising productivity demands, and the need to operate in unstructured environments. Robotics, particularly soft robotics, offers promising solutions for automating delicate tasks such as fruit harvesting. While numerous soft grippers have been proposed, most [...] Read more.
Agriculture is facing increasing challenges due to labor shortages, rising productivity demands, and the need to operate in unstructured environments. Robotics, particularly soft robotics, offers promising solutions for automating delicate tasks such as fruit harvesting. While numerous soft grippers have been proposed, most focus on grasping and lack the capability to detach fruits with rigid peduncles, which require cutting. This paper presents a novel modular hexagonal soft gripper that integrates soft pneumatic actuators, embedded mechano-optical force sensors for real-time contact monitoring, and a self-centering iris-type cutting mechanism. The entire system is 3D-printed, enabling low-cost fabrication and rapid customization. Experimental validation demonstrates successful harvesting of bell peppers and identifies cutting limitations in tougher crops such as aubergine, primarily due to material constraints in the actuation system. This dual-capability design contributes to the development of multifunctional robotic harvesters capable of adapting to a wide range of fruit types with minimal requirements for perception and mechanical reconfiguration. Full article
(This article belongs to the Special Issue Soft Actuators and Robotics—2nd Edition)
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22 pages, 2508 KB  
Article
Intelligent Vehicle Driving Decisions and Longitudinal–Lateral Trajectory Planning Considering Road Surface State Mutation
by Yongjun Yan, Chao Du, Yan Wang and Dawei Pi
Actuators 2025, 14(9), 431; https://doi.org/10.3390/act14090431 - 1 Sep 2025
Viewed by 321
Abstract
In an intelligent driving system, the rationality of driving decisions and the trajectory planning scheme directly determines the safety and stability of the system. Existing research mostly relies on high-definition maps and empirical parameters to estimate road adhesion conditions, ignoring the direct impact [...] Read more.
In an intelligent driving system, the rationality of driving decisions and the trajectory planning scheme directly determines the safety and stability of the system. Existing research mostly relies on high-definition maps and empirical parameters to estimate road adhesion conditions, ignoring the direct impact of real-time road status changes on the dynamic feasible domain of vehicles. This paper proposes an intelligent driving decision-making and trajectory planning method that comprehensively considers the influence factors of vehicle–road interaction. Firstly, real-time estimation of road adhesion coefficients was achieved based on the recursive least squares method, and a dynamic adhesion perception mechanism was constructed to guide the decision-making module to restrict lateral maneuvering behavior under low-adhesion conditions. A multi-objective lane evaluation function was designed for adaptive lane decision-making. Secondly, a longitudinal and lateral coupled trajectory planning framework was constructed based on the traditional lattice method to achieve smooth switching between lateral trajectory planning and longitudinal speed planning. The planned path is tracked based on a model predictive control algorithm and dual PID algorithm. Finally, the proposed method was verified on a co-simulation platform. The results show that this method has good safety, adaptability, and control stability in complex environments and dynamic adhesion conditions. Full article
(This article belongs to the Special Issue Actuator Fault Diagnosis, State Detection and Fault Tolerant Control for Ground and Rail Vehicles)
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31 pages, 14518 KB  
Article
A Novel Laminar Jamming Mechanism for Variable-Stiffness Robotic Arms
by Freddy Caro, Marc G. Carmichael and Jinchen Ji
Actuators 2025, 14(9), 430; https://doi.org/10.3390/act14090430 - 1 Sep 2025
Viewed by 489
Abstract
A central problem in human–robot interaction is the risk of severe injury in humans in the event of a collision with a rigid robot arm. The introduction of variable stiffness into a robot arm mitigates the effects of impact and generates a safe [...] Read more.
A central problem in human–robot interaction is the risk of severe injury in humans in the event of a collision with a rigid robot arm. The introduction of variable stiffness into a robot arm mitigates the effects of impact and generates a safe interaction in its compliant state. An approach to vary the stiffness of members in a robotic arm is Laminar Jamming. In this article, a new lock/unlock mechanism for Laminar Jamming is proposed. The solution consists of a pneumatic actuator that drives a trapezoidal pin to interfere mechanically with the layers, and, in turn, changing the stiffness of the Laminar Jamming Structure. Additionally, frames are placed along the structure to avoid local buckling of the layers. Experiments and finite element simulations were carried out to study the mechanical performance of this new mechanism. Experiments show that the proposed mechanism reached a maximum stiffness ratio of 3.65, which is 15% higher than the stiffness ratio of an equivalent flat clamp mechanism. Experiments also demonstrate that the proposed mechanism does not show the stick-slip phenomenon that exists in the flat clamp mechanism. Computational case studies were carried out to investigate the effects of the angle of the trapezoidal pin, the number of frames, the direction of the transverse force and the behavior at high deflections. Simulations show that the 30° trapezoidal pin has the highest stiffness for pressures larger than 500 kPa, three frames placed along the Laminar Jamming generate the maximum stiffness ratio, the stiffness slightly varies when the transverse force changes direction, and the stiffness decreases with increasing deflection. Full article
(This article belongs to the Special Issue Mechanical, Optical, and Acoustic Metamaterials and Anisotropic Design for Dynamic Control in Actuators and Sensors)
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21 pages, 7257 KB  
Article
A Study on the Transient Performance of Compensated PLL-Type Estimators for Sensorless IPMSMs
by Dongwoo Lee
Actuators 2025, 14(9), 429; https://doi.org/10.3390/act14090429 - 31 Aug 2025
Viewed by 264
Abstract
The transient performance of sensorless control for interior permanent magnet synchronous motors (IPMSMs), based on back-electromotive force (back-EMF) estimation, is a critical factor in ensuring the high reliability of motor drive systems. Although rotor speed and position can be accurately estimated under steady-state [...] Read more.
The transient performance of sensorless control for interior permanent magnet synchronous motors (IPMSMs), based on back-electromotive force (back-EMF) estimation, is a critical factor in ensuring the high reliability of motor drive systems. Although rotor speed and position can be accurately estimated under steady-state conditions, estimation errors tend to increase during transient states such as acceleration, deceleration, and load torque variations. The enhancement of transient stability is closely related to the overshoot in the estimated position and speed errors. In this paper, the maximum overshoot of the estimated position and speed errors during transient operation is analyzed. Furthermore, compensation strategies are proposed to reduce the magnitude of these overshoots. The effectiveness of the proposed sensorless control method is validated through comparative analysis with existing approaches. Full article
(This article belongs to the Section Control Systems)
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19 pages, 8125 KB  
Article
Flow Separation Delay Mechanism and Aerodynamic Enhancement via Optimized Flow Deflector Configurations
by Shengguan Xu, Siyi Wang, Hongquan Chen, Jianfeng Tan, Wei Li and Shuai Yin
Actuators 2025, 14(9), 428; https://doi.org/10.3390/act14090428 - 31 Aug 2025
Viewed by 343
Abstract
This study explores the critical role of the flow deflector in suppressing boundary layer separation and enhancing aerodynamic efficiency through systematic geometric parameterization and computational analysis. By defining eight key design variables, this research identifies optimal configurations that significantly delay flow separation at [...] Read more.
This study explores the critical role of the flow deflector in suppressing boundary layer separation and enhancing aerodynamic efficiency through systematic geometric parameterization and computational analysis. By defining eight key design variables, this research identifies optimal configurations that significantly delay flow separation at high angles of attack. Computational Fluid Dynamics (CFD) simulations reveal that optimized deflector geometries enhance suction peaks near the airfoil leading edge, redirect separated flow toward the upper surface, and inject momentum into the boundary layer to generate a more positive lift coefficient. The numerical results demonstrate that the optimized design achieves a 58.4% increase in lift coefficient and an 83.3% improvement in the lift–drag ratio by effectively mitigating large-scale vortical structures inherent in baseline configurations. Sensitivity analyses further highlight threshold-dependent “sudden-jump” behaviors in lift coefficients for parameters such as element spacing and deflection angles, while thickness exhibits minimal influence. Additionally, pre-stall optimizations show that strategically aligned deflectors preserve baseline performance with a 0.4% lift gain, whereas misaligned configurations degrade aerodynamic efficiency by up to 9.1%. These findings establish a direct correlation between deflector-induced flow redirection and separation suppression, offering actionable insights for passive flow control in stalled regimes. This research advances fundamental understanding of flow deflector-based separation management and provides practical guidelines for enhancing aerodynamic performance in aerospace applications. Full article
(This article belongs to the Special Issue Active Flow Control: Recent Advances in Fundamentals and Applications—3rd Edition)
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21 pages, 1415 KB  
Article
Vibration Reduction and Stability Investigation of Van Der Pol–Mathieu–Duffing Oscillator via the Nonlinear Saturation Controller
by Ashraf Taha EL-Sayed, Rageh K. Hussein, Yasser A. Amer, Sara S. Mahmoud, Sharif Abu Alrub and Taher A. Bahnasy
Actuators 2025, 14(9), 427; https://doi.org/10.3390/act14090427 - 31 Aug 2025
Viewed by 333
Abstract
This study investigates the effect of a nonlinear saturation controller (NSC) on the van der Pol–Mathieu–Duffing oscillator (VMDO). The oscillator is a single degree of freedom (DOF) system. It is driven by an external force. It is described by a nonlinear differential equation [...] Read more.
This study investigates the effect of a nonlinear saturation controller (NSC) on the van der Pol–Mathieu–Duffing oscillator (VMDO). The oscillator is a single degree of freedom (DOF) system. It is driven by an external force. It is described by a nonlinear differential equation (DE). The multiple-scale perturbation method (MSPT) is applied. It gives second-order analytical solutions. The first indirect Lyapunov method is used. It provides the frequency–response equation. It also shows the stability conditions. Internal resonance is included. The analysis considers steady-state responses. It studies simultaneous primary resonance with a 1:2 internal resonance (Λ1≅ϖ1 and ϖ1≅2ϖ2). Time–response simulations are presented. They show controlled and uncontrolled systems. Numerical solutions (NSs) are obtained with the fourth-order Runge–Kutta method (RK-4). They are compared with the approximate analytical solution (AS). The agreement is strong. It confirms the perturbation method. It shows that the method captures the main system dynamics. Full article
(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Nonlinear Control and Dynamics for MEMS)
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19 pages, 4016 KB  
Article
Multibody Dynamics Simulation of Upper Extremity Rehabilitation Exoskeleton During Task-Oriented Exercises
by Piotr Falkowski and Krzysztof Zawalski
Actuators 2025, 14(9), 426; https://doi.org/10.3390/act14090426 - 30 Aug 2025
Viewed by 468
Abstract
Population aging intensifies the demand for rehabilitation services, which are already suffering from staff shortages. In response to this challenge, the implementation of new technologies in physiotherapy is needed. For such a task, rehabilitation exoskeletons can be used. While designing such tools, their [...] Read more.
Population aging intensifies the demand for rehabilitation services, which are already suffering from staff shortages. In response to this challenge, the implementation of new technologies in physiotherapy is needed. For such a task, rehabilitation exoskeletons can be used. While designing such tools, their functionality and safety must be ensured. Therefore, simulations of their strength and kinematics must meet set criteria. This paper aims to present a methodology for simulating the dynamics of rehabilitation exoskeletons during activities of daily living and determining the reactions in the construction’s joints, as well as the required driving torques. The methodology is applied to the SmartEx-Home exoskeleton. Two versions of a multibody model were developed in the Matlab/Simulink environment—a rigid-only version and one with deformable components. The kinematic chain of construction was reflected with the driven rotational joints and modeled passive sliding open bearings. The simulation outputs include the driving torques and joint reaction forces and the torques for various input trajectories registered using IMU sensors on human participants. The results obtained in the investigation show that in general, to mobilize shoulder flexion/extension or abduction/adduction, around 30 Nm of torque is required in such a lightweight exoskeleton. For elbow flexion/extension, around 10 Nm of torque is needed. All of the reactions are presented in tables for all of the characteristic points on the passive and active joints, as well as the attachments of the extremities. This methodology provides realistic load estimations and can be universally used for similar structures. The presented numerical results can be used as the basis for a strength analysis and motor or force sensor selection. They will be directly implemented for the process of mass minimization of the SmartEx-Home exoskeleton based on computational optimization. Full article
(This article belongs to the Special Issue Advances in Intelligent Control of Actuator Systems)
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16 pages, 4547 KB  
Article
Semi-Active Vibration Controllers for Magnetorheological Fluid-Based Systems via Frequency Shaping
by Young T. Choi, Norman M. Wereley and Gregory J. Hiemenz
Actuators 2025, 14(9), 425; https://doi.org/10.3390/act14090425 - 30 Aug 2025
Viewed by 301
Abstract
This study introduces novel semi-active vibration controllers for magnetorheological (MR) fluid-based vibration control systems, specifically a band-pass frequency-shaped semi-active control (FSSC) and a narrow-band FSSC. These algorithms are designed without requiring an accurate damper model or system identification for control current input. Unlike [...] Read more.
This study introduces novel semi-active vibration controllers for magnetorheological (MR) fluid-based vibration control systems, specifically a band-pass frequency-shaped semi-active control (FSSC) and a narrow-band FSSC. These algorithms are designed without requiring an accurate damper model or system identification for control current input. Unlike active controllers, the FSSC algorithms treat the MR damper as a semi-active dissipative device, and their control signal is a control current, not a control force. The performance of both FSSC algorithms is evaluated through simulation using a single-degree-of-freedom (SDOF) MR fluid-based engine mount system. A comparative analysis with the classical semi-active skyhook control demonstrates the advantages of the proposed FSSC algorithms. Full article
(This article belongs to the Special Issue Advances in Electrorheological and Magnetorheological Materials: Material Design, Control and Industrial Applications)
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18 pages, 6348 KB  
Article
A Study on Reducing Loss in PCB Motor Stator Using Multi-Via Structure
by Su-Bin Jeon, Do-Hyeon Choi, Hyung-Sub Han, Yun-Ha Song and Won-Ho Kim
Actuators 2025, 14(9), 424; https://doi.org/10.3390/act14090424 - 29 Aug 2025
Viewed by 445
Abstract
This study proposes a multi-via structure as a loss-reduction design technique to mitigate current crowding in a slotless axial flux permanent magnet motor (AFPM) equipped with printed circuit board (PCB) stators. The PCB stator enables high current density operation through parallel copper-foil stacking [...] Read more.
This study proposes a multi-via structure as a loss-reduction design technique to mitigate current crowding in a slotless axial flux permanent magnet motor (AFPM) equipped with printed circuit board (PCB) stators. The PCB stator enables high current density operation through parallel copper-foil stacking and supports an ultra-compact structural configuration. However, current concentration in the via regions can increase copper loss and phase resistance. In this work, the via position and diameter were defined as design variables to perform a sensitivity analysis of current distribution and phase resistance variation. The effects of current density dispersion and the potential for copper loss reduction were evaluated using three-dimensional finite-element analysis (FEA). The results confirm that adopting a multi-via structure improves current path uniformity and reduces electrical losses, thereby enhancing overall efficiency. Furthermore, the analysis shows that excessive via enlargement or overuse does not necessarily yield optimal results and, in certain cases, may lead to localized current peaks. These findings demonstrate that the multi-via structure is an effective and appropriate design strategy for PCB stators and highlight the importance of optimized via placement tailored to each stator configuration. Full article
(This article belongs to the Special Issue Recent Developments in Precision Actuation Technologies)
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19 pages, 4270 KB  
Article
Fast Terminal Sliding Mode Control Based on a Novel Fixed-Time Sliding Surface for a Permanent Magnet Arc Motor
by Qiangren Xu, Gang Wang and Shuhua Fang
Actuators 2025, 14(9), 423; https://doi.org/10.3390/act14090423 - 29 Aug 2025
Viewed by 280
Abstract
A fast terminal sliding mode control based on a fixed-time sliding surface is proposed for a permanent magnet arc motor (PMAM), effectively improving speed response, control accuracy, and disturbance rejection capability. Due to its piecewise structure and advanced logarithmic characteristics, a PMAM is [...] Read more.
A fast terminal sliding mode control based on a fixed-time sliding surface is proposed for a permanent magnet arc motor (PMAM), effectively improving speed response, control accuracy, and disturbance rejection capability. Due to its piecewise structure and advanced logarithmic characteristics, a PMAM is subject to high-frequency disturbances. Additionally, it is also influenced by external disturbances. To address this, a sliding mode reaching law that combines terminal terms, linear terms, and switching terms is designed to reduce chattering and enhance robustness. Furthermore, to improve the convergence speed of the sliding mode and disturbance rejection ability, a novel fixed-time converging sliding surface based on a variable exponent terminal term is introduced. Numerical simulations verify the convergence and disturbance rejection capabilities of the proposed sliding surface. Stability based on the Lyapunov theorem is strictly proven. Experimental results validate the effectiveness and superiority of the proposed algorithm. Full article
(This article belongs to the Special Issue High-Performance Control of Electromechanical Servo System Based on Motor/Hydraulic Actuator)
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