Actuators

32 pages, 4807 KB

Open AccessArticle

Force-Closure-Based Weighted Hybrid Force/Position Fuzzy Coordination Control for Dual-Arm Robots

by Jun Dai, Yi Zhang and Weiqiang Dou

Actuators 2025, 14(10), 471; https://doi.org/10.3390/act14100471 - 26 Sep 2025

There is a strong coupling between two arms in cooperative operations of dual-arm robots. To enhance the coordination and cooperation ability of dual-arm robots, a force-closure-based weighted hybrid force/position fuzzy coordination control method is proposed. Firstly, to improve the grasping stability of dual-arm [...] Read more.

There is a strong coupling between two arms in cooperative operations of dual-arm robots. To enhance the coordination and cooperation ability of dual-arm robots, a force-closure-based weighted hybrid force/position fuzzy coordination control method is proposed. Firstly, to improve the grasping stability of dual-arm robots, the force-closure dynamic constraints are established by combining the friction cone constraints with the force and torque balance constraints. Then the optimal distribution of contact force is performed according to the minimum energy consumption principle. Secondly, to enhance the coordination of dual-arm robots, the weighted hybrid force/position control method is modified by adding the synchronization error between two arms. Then the Lyapunov method is adopted to prove the stability of the proposed coordination control method. Thirdly, the fuzzy self-tuning technique is adopted to adjust the control gains automatically. Lastly, a simulation and experiment are performed for collaborative transport. The results show that, compared with the position coordination control and the traditional hybrid force/position control, the weighted hybrid force/position fuzzy coordination control can improve control accuracy and has good cooperation ability and strong robustness. Therefore, the proposed method can effectively realize the coordination control of dual-arm robots. Full article

(This article belongs to the Section Actuators for Robotics)

22 pages, 2922 KB

Open AccessArticle

Fuzzy Adaptive PID-Based Tracking Control for Autonomous Underwater Vehicles

by Shicheng Fan, Haoming Wang, Changyi Zuo and Junqiang Han

Actuators 2025, 14(10), 470; https://doi.org/10.3390/act14100470 - 26 Sep 2025

Abstract

This paper addresses the trajectory tracking control problem of Autonomous Underwater Vehicles (AUVs). A comprehensive mathematical model is first established based on Newtonian mechanics, incorporating both kinematic and dynamic equations. By reasonably neglecting the minor influence of roll motion, a five-degree-of-freedom (5-DOF) underactuated [...] Read more.

This paper addresses the trajectory tracking control problem of Autonomous Underwater Vehicles (AUVs). A comprehensive mathematical model is first established based on Newtonian mechanics, incorporating both kinematic and dynamic equations. By reasonably neglecting the minor influence of roll motion, a five-degree-of-freedom (5-DOF) underactuated AUV model is derived. Considering the strong nonlinearities, high coupling, and time-varying hydrodynamic parameters typical of underwater environments, a fuzzy adaptive PID controller is proposed. This controller combines the adaptability of fuzzy logic with the structural simplicity and reliability of PID control, making it well-suited to the demanding requirements of AUV motion control. Extensive simulation experiments are conducted to evaluate the controller’s performance under various operating conditions. The results show that the fuzzy adaptive PID controller significantly outperforms conventional PID and standalone fuzzy logic controllers in terms of convergence speed and oscillation suppression. Furthermore, a theoretical stability analysis is provided to ensure that the proposed control system remains stable under time-varying fuzzy gain scheduling, confirming its effectiveness and potential for practical application in underwater vehicle control. Full article

(This article belongs to the Section Control Systems)

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23 pages, 23760 KB

Open AccessArticle

Optimization of Inlet Flow Pattern and Performance Enhancement in Oil-Gas Multiphase Pumps Using Helical Static Mixer

by Wei Han, Lingrui Zhu, Longlong Zhao, Huiyu Chen, Hongfa Huang, Wanquan Deng and Lei Ji

Actuators 2025, 14(10), 469; https://doi.org/10.3390/act14100469 - 26 Sep 2025

Abstract

With increasing global energy demand and depletion of onshore oil–gas resources, deep-sea hydrocarbon exploration and development have become strategically vital. As core subsea transportation equipment, the performance of helico-axial multiphase pumps directly determines the efficiency and economic feasibility of deep-sea extraction. However, non-uniform [...] Read more.

With increasing global energy demand and depletion of onshore oil–gas resources, deep-sea hydrocarbon exploration and development have become strategically vital. As core subsea transportation equipment, the performance of helico-axial multiphase pumps directly determines the efficiency and economic feasibility of deep-sea extraction. However, non-uniform inflow patterns caused by uneven gas–liquid distribution in pipelines degrade pressure-boosting capability and reduce pump efficiency under actual operating conditions. To address this, an optimization method employing helical static mixers was developed. A mixer with a 180° helical angle was designed and installed upstream of the pump inlet. Numerical simulations demonstrate that the mixer enhances gas-phase distribution uniformity in stratified flow, improving efficiency and head across varying gas void fractions (GVFs). At a stratification height ratio (Ψ) of 0.32, efficiency increased by 15.41% and head rose by 15.64 m, while turbulent kinetic energy (TKE) at the impeller outlet decreased by up to 50%. For slug flow conditions, the mixer effectively suppressed gas volume fraction fluctuations, consistently improving efficiency under different slug flow coefficients (φ) with a maximum head increase of 9.82%. The optimized flow field exhibits uniform gas–liquid velocity distribution, stable pressure boosting, and significantly reduced TKE intensity within impeller passages. Full article

(This article belongs to the Special Issue Advanced Actuators and Magnetic Fluid Systems: Design, Control, and Applications)

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17 pages, 5408 KB

Open AccessArticle

Optimal Design of 3D-Printed Flexible Fingers for Robotic Soft Gripping of Agricultural Products

by Ciprian Lapusan, Radu Stefan Chiorean and Radu Matis

Actuators 2025, 14(10), 468; https://doi.org/10.3390/act14100468 - 25 Sep 2025

Abstract

Handling delicate agricultural products, such as tomatoes, requires careful attention from workers during harvesting, sorting, and packaging processes. This labor-intensive approach is often inefficient and susceptible to human error. A potential solution to improve efficiency is the development of automated systems capable of [...] Read more.

Handling delicate agricultural products, such as tomatoes, requires careful attention from workers during harvesting, sorting, and packaging processes. This labor-intensive approach is often inefficient and susceptible to human error. A potential solution to improve efficiency is the development of automated systems capable of replacing manual labor. However, such systems face significant challenges due to the irregular shapes and fragility of these products, requiring specialized adaptable and soft gripping mechanisms. In this context, this paper introduces a parametric design methodology for 3D-printed flexible fingers in soft grippers, tailored for agricultural applications. The approach was tested in a case study that targeted soft agricultural products with diameters between 45 and 75 mm. Three finger topologies were modeled and compared to identify an optimal configuration. A prototype was then developed using 3D printing with Z-SemiFlex. Experimental tests confirmed that the prototype could grasp different fruits reliably and without surface damage. It achieved an Average Precision (AP) of 87.5% for tomatoes and 92.5% for mandarins across 80 trials. These results validate the feasibility of the proposed design methodology for fingers in soft grippers. Full article

(This article belongs to the Section Actuators for Robotics)

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18 pages, 3921 KB

Open AccessArticle

One Innovative Method for Improving the Power Density and Efficiency of Electro-Hydrostatic Actuators

by Zhenfei Ling, Fengqi Zhou, Hao Liu, Bo Yang and Xiaoping Ouyang

Actuators 2025, 14(10), 467; https://doi.org/10.3390/act14100467 - 25 Sep 2025

Abstract

Although electro-hydrostatic actuators (EHAs) hold broad application prospects in more-electric aircraft and high-end equipment, they face a difficult trade-off between dynamic response and energy efficiency. To simultaneously enhance the dynamic response and energy efficiency of the EHA, this paper designs an innovative variable [...] Read more.

Although electro-hydrostatic actuators (EHAs) hold broad application prospects in more-electric aircraft and high-end equipment, they face a difficult trade-off between dynamic response and energy efficiency. To simultaneously enhance the dynamic response and energy efficiency of the EHA, this paper designs an innovative variable pump displacement and variable motor speed (VPVM) configuration that utilizes an electro-hydraulic servo valve for active displacement control. To address the flow mismatch problem associated with traditional asymmetric single-rod cylinders without reducing the power density of EHA, this paper also designs an innovative symmetric single-rod cylinder configuration. Based on the above two innovative configurations, this paper further develops a corresponding EHA prototype with a rated power density of 0.72 kW/kg. Simulation and experimental results demonstrate that compared to the traditional EHA with the fixed pump displacement and variable motor speed configuration (FPVM-EHA), the EHA with the proposed VPVM configuration (VPVM-EHA) not only improves energy efficiency and reduces motor heat generation under low-speed and heavy-load conditions, but also achieves a dynamic response close to that of the FPVM-EHA under fast dynamic response conditions. Full article

(This article belongs to the Section Control Systems)

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20 pages, 3362 KB

Open AccessArticle

Analysis and Suppression Method of Drag Torque in Wide-Speed No-Load Wet Clutch

by Rui Liu, Chao Wei, Lei Zhang, Lin Zhang, Siwen Liang and Mao Xue

Actuators 2025, 14(10), 466; https://doi.org/10.3390/act14100466 - 25 Sep 2025

Abstract

Under no-load conditions, the wet clutch of vehicles generates drag torque across a wide speed range, which increases power loss in the transmission system and significantly impacts its efficiency and reliability. To address the clutch drag issue over a wide speed range, this [...] Read more.

Under no-load conditions, the wet clutch of vehicles generates drag torque across a wide speed range, which increases power loss in the transmission system and significantly impacts its efficiency and reliability. To address the clutch drag issue over a wide speed range, this study first establishes a low-speed drag torque model that simultaneously considers the viscous friction effects in both the complete oil film region and the oil film rupture zone of the friction pair clearance. Subsequently, by solving the fluid-structure interaction dynamics model of the friction plates, the collision force between high-speed friction pairs and the resulting friction torque are determined, forming a method for calculating high-speed collision-induced drag torque. Building on this, a unified drag torque model for wet clutches across a wide speed range is developed, integrating both viscous and collision-induced drag torques. The validity of the wide-speed-range drag torque model is verified through experiments. The results indicate that as oil temperature and friction pair clearance increase, the drag torque decreases and the rotational speed corresponding to the peak drag torque is reduced, while the onset of collision phenomena occurs earlier. Conversely, with an increase in oil supply flow rate, the drag torque rises and the rotational speed corresponding to the peak drag torque increases, but the onset of collision phenomena is delayed. Finally, with the optimization objectives of minimizing the peak drag torque in the low-speed range and the total drag torque at the maximum speed in the high-speed range, an optimization design model for the surface grooves of the clutch friction plates is constructed. An optimized groove pattern is obtained, and its effectiveness in suppressing drag torque across a wide speed range is experimentally validated. Full article

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

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30 pages, 10255 KB

Open AccessArticle

Hybrid Design Optimization Methodology for Electromechanical Linear Actuators in Automotive LED Headlights

by Mario Đurić, Luka Selak and Drago Bračun

Actuators 2025, 14(10), 465; https://doi.org/10.3390/act14100465 - 24 Sep 2025

Abstract

The development of electromechanical linear actuators (EMLAs) aims at compactness, energy efficiency, and high reliability. Conventional design methods often rely on costly prototypes and individual considerations of mechanics, electromagnetics, and control dynamics. This leads to long development cycles, inadequate treatment of nonlinear effects, [...] Read more.

The development of electromechanical linear actuators (EMLAs) aims at compactness, energy efficiency, and high reliability. Conventional design methods often rely on costly prototypes and individual considerations of mechanics, electromagnetics, and control dynamics. This leads to long development cycles, inadequate treatment of nonlinear effects, and suboptimal performance. To address these challenges, our paper introduces a novel hybrid design methodology, integrating Analytical Modeling, Finite Element Analysis (FEA), Genetic Algorithms (GAs), and targeted experiments. Analytical Modeling provides rapid sizing, FEA combined with a GA refines geometry, and targeted experiments quantify nonlinear effects (friction, wear, thermal variability, and dynamic resonances). Unlike conventional methods, the integration is performed within iterative loops, using empirical data to refine simulation assumptions. As a result, development time is reduced by 30% and nonlinear effects are precisely addressed. The method is demonstrated on an automotive-grade EMLA. Its design is based on a claw-pole Permanent Magnet Stepper Motor, a trapezoidal lead screw, and an open-loop control with Hall effect end-position detection. After applying the method, the EMLA delivers more than 40 N of push force and achieves 600,000 actuations under the required conditions, making it suitable for various applications. Full article

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

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86 pages, 4498 KB

Open AccessReview

Autonomous Driving in Agricultural Machinery: Advancing the Frontier of Precision Agriculture

by Qingchao Liu, Ruohan Yu, Haoda Suo, Yingfeng Cai, Long Chen and Haobin Jiang

Actuators 2025, 14(9), 464; https://doi.org/10.3390/act14090464 - 22 Sep 2025

Abstract

Increasing global food production to address challenges from population growth, labor shortages, and climate change necessitates a significant enhancement of agricultural sustainability. Autonomous agricultural machinery, a recognized application of precision agriculture, offers a promising solution to boost productivity, resource efficiency, and environmental sustainability. [...] Read more.

Increasing global food production to address challenges from population growth, labor shortages, and climate change necessitates a significant enhancement of agricultural sustainability. Autonomous agricultural machinery, a recognized application of precision agriculture, offers a promising solution to boost productivity, resource efficiency, and environmental sustainability. This study presents a systematic review of autonomous driving technologies for agricultural machinery based on 506 rigorously selected publications. The review emphasizes three core aspects: navigation reliability assurance, motion control mechanisms for both vehicles and implements, and actuator fault-tolerance strategies in complex agricultural environments. Applications in farmland, orchards, and livestock farming demonstrate substantial potential. This study also discusses current challenges and future development trends. It aims to provide a reference and technical guidance for the engineering implementation of intelligent agricultural machinery and to support sustainable agricultural transformation. 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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16 pages, 4282 KB

Open AccessArticle

A Fast Response, High Flow Rate, Low Power Consumption Pneumatic Proportional Valve for Medical Ventilators Driven by a Piezoelectric Bimorph

by Shuai Ren, Junling Chen, Tao Wang and Bingbing Ma

Actuators 2025, 14(9), 463; https://doi.org/10.3390/act14090463 - 22 Sep 2025

Abstract

In recent years, pneumatic proportional valves have become increasingly prevalent in ventilators, particularly proportional solenoid valves. However, these traditional valves face challenges, including a slow response, being prone to overheating from long-term work, and high power consumption. This study presents the development of [...] Read more.

In recent years, pneumatic proportional valves have become increasingly prevalent in ventilators, particularly proportional solenoid valves. However, these traditional valves face challenges, including a slow response, being prone to overheating from long-term work, and high power consumption. This study presents the development of a fast response, high flow rate, and low power consumption pneumatic proportional valve specifically designed for medical ventilators. Utilizing a piezoelectric bimorph as the actuator, we innovatively eliminate movable components such as springs while ensuring effective sealing of the valve. A support structure was designed to enhance the mechanical performance of the piezoelectric bimorph. A testing platform was established to rigorously assess the valve’s performance. The results indicate that the valve can achieve a maximum output flow rate of approximately 130 L/min at an input pressure of 4 bar, with a hysteresis rate of 25.3%, a response time of under 10 ms, and a power consumption of just 0.07 W. Furthermore, a comparative analysis with existing commercial proportional solenoid valves demonstrated that it has superior performance in terms of response speed, flow rate, and power efficiency. The piezoelectric proportional valve developed in this study holds the potential to replace conventional proportional solenoid valves, significantly enhancing the response speed of ventilators, reducing their overall power consumption, and facilitating the development of portable ventilators. Full article

(This article belongs to the Section Actuators for Medical Instruments)

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22 pages, 5174 KB

Open AccessArticle

Pre-Processing Optimisation of Robot Control to Reduce Energy Consumption

by Petr Vavruska, Strahinja Protić and Tomas Kratena

Actuators 2025, 14(9), 462; https://doi.org/10.3390/act14090462 - 22 Sep 2025

Abstract

The huge growth in the utilisation of six-axis robots in various technological applications in production calls for a detailed focus on the process of preparing Numerical Control (NC) programmes for effective robot control. Considerable attention is currently being paid to optimisation by increasing [...] Read more.

The huge growth in the utilisation of six-axis robots in various technological applications in production calls for a detailed focus on the process of preparing Numerical Control (NC) programmes for effective robot control. Considerable attention is currently being paid to optimisation by increasing stiffness, but there is also a need to focus on reducing energy consumption in robot control. Focusing on reducing energy consumption is highly justified given the widespread adoption of robotic systems across diverse manufacturing technologies and the significant potential for application. This is particularly relevant today, when minimising production costs is a critical industrial objective. A redundant degree of freedom—which is the possibility to rotate around the end-effector axis and thus influence the adjustment of the rotation of the individual robot joints—can be used for this purpose. Therefore, this paper exploits this redundant degree of freedom to set up a proper robot configuration that reduces energy consumption. The user-friendly solution, including the algorithm design and processing through a function, could be effectively implemented within an industry-standard post-processor solution for generating NC programmes for robots. This solution is unique as it is used for the optimisation of the working section of the toolpaths, where continuous control of the end-effector movement during manufacturing operations occurs. The solution was verified on a KUKA KR60 HA robot; however, it is applicable to any industrial six-axis robot. Substantial energy savings were obtained in multi-axis toolpath operations, with a 7.5% reduction in total energy consumption when using the optimised NC programme. Full article

(This article belongs to the Special Issue Motion Planning, Trajectory Prediction, and Control for Robotics)

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24 pages, 2157 KB

Open AccessArticle

Research on Aerodynamic Force/Thrust Vector Combined Trajectory Optimization Method for Hypersonic Drones Based on Deep Reinforcement Learning

by Zijun Zhang, Yunfan Zhou, Leichao Yang, Wenzhong Jin and Jun Wang

Actuators 2025, 14(9), 461; https://doi.org/10.3390/act14090461 - 22 Sep 2025

Abstract

This paper addresses the cruise range maximization problem for hypersonic drones by proposing a combined aerodynamic force/thrust vector trajectory optimization method. A novel continuous linear parameterization strategy for trajectory optimization is innovatively developed, achieving continuous thrust vector trajectory optimization throughout the entire flight [...] Read more.

This paper addresses the cruise range maximization problem for hypersonic drones by proposing a combined aerodynamic force/thrust vector trajectory optimization method. A novel continuous linear parameterization strategy for trajectory optimization is innovatively developed, achieving continuous thrust vector trajectory optimization throughout the entire flight using only 21 parameters through recursive linear function design. This approach reduces parameter dimensionality and effectively addresses sparse rewards and training difficulties in reinforcement learning. The study integrates the Deep Deterministic Policy Gradient (DDPG) algorithm with deep residual networks for trajectory optimization, systematically exploring the impact mechanisms of different aerodynamic force and thrust vector combination modes on range performance. Through collaborative trajectory optimization of thrust vectors and flight height, simulation results demonstrate that the combined trajectory optimization strategy achieves a total range enhancement of approximately 146.14 km compared to pure aerodynamic control, with continuous linearly parameterized thrust vector trajectory optimization providing superior performance over traditional segmented methods. These results verify the significant advantages of the proposed trajectory optimization approach and the effectiveness of the deep reinforcement learning framework. Full article

(This article belongs to the Section Aerospace Actuators)

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32 pages, 4787 KB

Open AccessReview

Performance Comparison of Mechanical and Ferrofluidic Micropumps: Structural and Operational Perspectives

by Xing Zhou, Zhenggui Li, Baozhu Han, Qinkui Guo and Zhichao Qing

Actuators 2025, 14(9), 460; https://doi.org/10.3390/act14090460 - 20 Sep 2025

Abstract

Since the successful implementation of microfluidic technology in biomedical applications, research on micropumps—the central component of these systems—has gained significant momentum. Benefiting from advancements in pump materials and corresponding fabrication methods, micropumps have evolved from structurally complex mechanical designs to simpler non-mechanical configurations. [...] Read more.

Since the successful implementation of microfluidic technology in biomedical applications, research on micropumps—the central component of these systems—has gained significant momentum. Benefiting from advancements in pump materials and corresponding fabrication methods, micropumps have evolved from structurally complex mechanical designs to simpler non-mechanical configurations. This paper reviews well-developed mechanical micropumps, discussing their diaphragms, pump chambers, materials, and other aspects to outline their developmental trajectory and current applications, while also highlighting their limitations. After identifying the shortcomings of traditional micropumps, we introduce the concept of ferrofluid-based micropumps, emphasizing their structural simplicity, self-sealing capability, and recoverability. Previous research on ferrofluidic micropumps is summarized, demonstrating their superior performance in certain aspects. Finally, we provide an outlook on their potential applications in biomedicine and specialized fields. Full article

(This article belongs to the Section Miniaturized and Micro Actuators)

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24 pages, 102794 KB

Open AccessArticle

Agentic AI for Real-Time Adaptive PID Control of a Servo Motor

by Tariq Mohammad Arif and Md Adilur Rahim

Actuators 2025, 14(9), 459; https://doi.org/10.3390/act14090459 - 20 Sep 2025

Abstract

This study explores a novel approach of using large language models (LLMs) in the real-time Proportional–Integral–Derivative (PID) control of a physical system, the Quanser QUBE-Servo 2. We investigated whether LLMs, used with an Artificial Intelligence (AI) agent workflow platform, can participate in the [...] Read more.

This study explores a novel approach of using large language models (LLMs) in the real-time Proportional–Integral–Derivative (PID) control of a physical system, the Quanser QUBE-Servo 2. We investigated whether LLMs, used with an Artificial Intelligence (AI) agent workflow platform, can participate in the live tuning of PID parameters through natural language instructions. Two AI agents were developed: a control agent that monitors the system performance and decides if tuning is necessary, and an Optimizer Agent that updates PID gains using either a guided system prompt or a self-directed free approach within a safe parameter range. The LLM integration was implemented through Python programming and Flask-based communication between the AI agents and the hardware system. Experimental results show that LLM-based tuning approaches can effectively reduce standard error metrics, such as IAE, ISE, MSE, and RMSE. This study presents one of the first implementations of real-time PID tuning powered by LLMs, and it has the potential to become a novel alternative to classical control, as well as machine learning or reinforcement learning-based approaches. The results are promising for using agentic AI in heuristic-based tuning and the control of complex physical systems, marking the shift toward more human-centered, explainable, and adaptive control engineering. Full article

(This article belongs to the Special Issue Advanced Technologies in Actuators for Control Systems)

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30 pages, 9701 KB

Open AccessArticle

Lightweight Adaptive Feature Compression and Dynamic Network Fusion for Rotating Machinery Fault Diagnosis Under Extreme Conditions

by Kaiyi Zhang, Xuling Liu, Guohua Yang, Kun Zhai, Gaofei An, Yusong Zhang and Chaofeng Peng

Actuators 2025, 14(9), 458; https://doi.org/10.3390/act14090458 - 19 Sep 2025

Abstract

Reliable fault diagnosis of rotating machines under extreme conditions—strong speed, load variation, intense noise, and severe class imbalance—remains a critical industrial challenge. We develop an ultra-light yet robust framework to accurately detect weak bearing, and gear faults when less than 5% labels, 10 [...] Read more.

Reliable fault diagnosis of rotating machines under extreme conditions—strong speed, load variation, intense noise, and severe class imbalance—remains a critical industrial challenge. We develop an ultra-light yet robust framework to accurately detect weak bearing, and gear faults when less than 5% labels, 10 dB noise, 100:1 imbalance and plus or minus 20% operating-point drift coexist. Methods: The proposed Adaptive Feature Module–Conditional Dynamic GRU Auto-Encoder (AFM-CDGAE) first compresses 512 d spectra into 32/48 d “feature modules” via K-means while retaining 98.4% fault energy. A workload-adaptive multi-scale convolution with spatial attention and CPU-aware λ-scaling suppresses noise and adapts to edge–device load. A GRU-based auto-encoder, enhanced by self-attention, is trained with balanced-subset sampling and minority-F1-weighted voting to counter extreme imbalance. On Paderborn (5-class) and CWRU (7-class) benchmarks, the 0.87 M-parameter model achieves 99.12% and 98.83% Macro-F1, surpassing five recent baselines by 3.1% under normal and 5.4% under the above extreme conditions, with only 1.5 to 1.8% F1 drop versus 6.7% for baselines. AFM-CDGAE delivers state-of-the-art accuracy, minimal footprint and strong robustness, enabling real-time deployment at the edge. Full article

(This article belongs to the Section Actuators for Manufacturing Systems)

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22 pages, 3892 KB

Open AccessArticle

Adaptive Sliding Mode Control for Unmanned Surface Vehicle Trajectory Tracking Based on Event-Driven and Control Input Quantization

by Zhihui Li, Mengyuan Li, Xinrui Jing, Changfu Yuan and Kai Wang

Actuators 2025, 14(9), 457; https://doi.org/10.3390/act14090457 - 18 Sep 2025

Abstract

This primary study aims to optimize network resource utilization efficiency in marine control systems. A novel event-triggering condition is proposed to significantly reduce communication traffic, where the error norm is squared while the input norm remains linear. To simulate realistic environmental disturbances, bounded [...] Read more.

This primary study aims to optimize network resource utilization efficiency in marine control systems. A novel event-triggering condition is proposed to significantly reduce communication traffic, where the error norm is squared while the input norm remains linear. To simulate realistic environmental disturbances, bounded unknown parameters are incorporated. Within the networked transmission architecture, input quantization is introduced, enabling the design of a quantized feedback controller without prior knowledge of quantization parameters. By integrating the event-triggering mechanism with sliding mode control, a quantized feedback control system is developed. The closed-loop system’s stability is rigorously proven via Lyapunov theory, with guaranteed boundedness of trajectory tracking errors. Numerical simulations validate the effectiveness of the proposed method for marine vehicle trajectory control under environmental disturbances. Full article

(This article belongs to the Special Issue Control System of Autonomous Surface Vehicle)

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22 pages, 4299 KB

Open AccessArticle

Motion Control of Gallium-Based Liquid Metal Droplets in Abrasive Suspensions Within a Flow Channel

by Yapeng Ma, Baoqi Feng, Kaixiang Li and Lei Zhang

Actuators 2025, 14(9), 456; https://doi.org/10.3390/act14090456 - 18 Sep 2025

Abstract

Gallium-based room-temperature liquid metal is a promising multifunctional material for microfluidics and precision machining due to its high mobility and deformability. However, precise motion control of gallium-based liquid metal droplets, especially in abrasive particle-laden fluids, remains challenging. This study presents a hybrid control [...] Read more.

Gallium-based room-temperature liquid metal is a promising multifunctional material for microfluidics and precision machining due to its high mobility and deformability. However, precise motion control of gallium-based liquid metal droplets, especially in abrasive particle-laden fluids, remains challenging. This study presents a hybrid control framework for regulating droplet motion in a one-dimensional PMMA channel filled with NaOH-based SiC abrasive suspensions. A dynamic model incorporating particle size and concentration effects on the damping coefficient was established. The system combines a setpoint controller, high-resolution voltage source, and vision feedback to guide droplets to target positions with high accuracy. Experimental validation and MATLAB simulations confirm that the proposed dynamic damping control strategy ensures stable, rapid, and precise positioning of droplets, minimizing motion fluctuations. This approach offers new insights into the manipulation of gallium-based liquid metal droplets for targeted material removal in micro-manufacturing, with potential applications in microelectronics and high-precision surface finishing. Full article

(This article belongs to the Section Control Systems)

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17 pages, 1898 KB

Open AccessArticle

Prescribed-Performance-Bound-Based Adaptive Fault-Tolerant Control for Rigid Spacecraft Attitude Systems

by Zixuan Chen, Teng Cao, Shaohua Yang and Yang Cao

Actuators 2025, 14(9), 455; https://doi.org/10.3390/act14090455 - 17 Sep 2025

Abstract

This paper investigates the attitude control problems of spacecraft subject to external disturbances and compound actuator faults, including both additive and multiplicative components. To address these problems, an improved learning observer (ILO) is proposed. Compared to traditional learning observers (TLOs), the improved learning [...] Read more.

This paper investigates the attitude control problems of spacecraft subject to external disturbances and compound actuator faults, including both additive and multiplicative components. To address these problems, an improved learning observer (ILO) is proposed. Compared to traditional learning observers (TLOs), the improved learning observer incorporates the previous-step state estimation error as an iterative term. Based on the observer’s outputs, a robust adaptive fault-tolerant attitude control scheme is developed using the backstepping method, under a prescribed performance bound (PPB). This control framework guarantees that the attitude tracking error adheres to prescribed transient performance specifications, such as bounded overshoot and accelerated convergence. Unlike conventional control schemes, the proposed approach ensures that system trajectories remain strictly within the desired bound throughout the transient process. A comprehensive Lyapunov-based analysis rigorously demonstrates the global uniform ultimate boundedness of all closed-loop signals. Numerical simulations substantiate the efficacy of the proposed approach, highlighting the enhanced disturbance estimation capability of the ILO in comparison to the TLO, as well as the superior transient tracking performance of the PPB-based control strategy relative to existing methods. Full article

(This article belongs to the Section Aerospace Actuators)

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19 pages, 1722 KB

Open AccessArticle

Global-Initialization-Based Model Predictive Control for Mobile Robots Navigating Nonconvex Obstacle Environments

by Seung-Mok Lee

Actuators 2025, 14(9), 454; https://doi.org/10.3390/act14090454 - 17 Sep 2025

Abstract

This paper proposes a nonlinear model predictive control (MPC) framework initialized using an initial-guess particle swarm optimization (IG-PSO) algorithm for mobile robots navigating in environments with nonconvex obstacles. The proposed method is designed to address the local minimum problem inherent in conventional optimization-based [...] Read more.

This paper proposes a nonlinear model predictive control (MPC) framework initialized using an initial-guess particle swarm optimization (IG-PSO) algorithm for mobile robots navigating in environments with nonconvex obstacles. The proposed method is designed to address the local minimum problem inherent in conventional optimization-based MPC by incorporating a PSO-based global search method to generate effective initial guesses. In addition, a grid-based representation of the nonconvex obstacles is implemented to systematically define the collision avoidance constraints within the MPC formulation. The proposed method was validated in real-time simulations using the Robot Operating System (ROS) and the Gazebo physics simulator. The results demonstrate that the proposed MPC initialized by IG-PSO generates collision-free trajectories that avoid local minima and track the desired reference trajectory in environments with nonconvex obstacles. Compared with conventional IPOPT-based MPC, the proposed method exhibited improved performance in the tested scenario. The proposed method also maintains real-time control capabilities by selectively activating the IG-PSO algorithm only as required. The findings of this study demonstrate the potential of the proposed framework for robust and efficient trajectory planning in complex, nonconvex obstacle environments. Full article

(This article belongs to the Section Actuators for Robotics)

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20 pages, 5120 KB

Open AccessArticle

Fast Fourier Transform-Based Activation and Monitoring of Micro-Supercapacitors: Enabling Energy-Autonomous Actuators

by Negar Heidari, Parviz Norouzi, Alireza Badiei and Ebrahim Ghafar-Zadeh

Actuators 2025, 14(9), 453; https://doi.org/10.3390/act14090453 - 16 Sep 2025

Abstract

This work provides the first demonstration of FFTCCV as a dual-purpose method, serving both as a real-time diagnostic tool and as a phase- and morphology-engineering strategy. By adjusting the scan rate, FFTCCV directs the crystallographic evolution of Ni (OH)₂ on Ni foam—stabilizing [...] Read more.

This work provides the first demonstration of FFTCCV as a dual-purpose method, serving both as a real-time diagnostic tool and as a phase- and morphology-engineering strategy. By adjusting the scan rate, FFTCCV directs the crystallographic evolution of Ni (OH)₂ on Ni foam—stabilizing α-nanoflakes at 0.7 V·s⁻¹ and β-platelets at 0.007 V·s⁻¹—while simultaneously enabling electrode-resolved ΔQ tracking and predictive state-of-health (SoH) monitoring. This approach enabled the precise regulation of electrode morphology and phase composition, yielding high areal capacitance (546.5 mF·cm⁻² at 5 mA·cm⁻²) with ~75% retention after 3000 cycles. These improvements advance the development of high-performance micro-supercapacitors, facilitating their integration into wearable and miniaturized devices where compact and durable energy storage is required. Beyond performance enhancement, FFTCCV also enabled continuous monitoring of capacitance during extended operation (up to 40,000 s). By recording both anodic and cathodic responses, the method provided time-resolved insights into device stability and revealed characteristic signatures of electrode degradation, phase transitions, and morphological changes. Such detection allows recognition of early failure pathways that are not accessible through conventional testing. This monitoring capability functions as an embedded health sensor, offering a pathway for predictive diagnosis of supercapacitor failure. Such functionality is particularly important for energy-driven actuators and smart materials, where uninterrupted operation and preventive maintenance are critical. FFTCCV therefore provides a scalable strategy for developing energy-autonomous microsystems with improved performance and real-time state-of-health monitoring. Full article

(This article belongs to the Section Miniaturized and Micro Actuators)

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