Actuators

21 pages, 3678 KB

Open AccessArticle

Dynamic Error Improved Model-Free Adaptive Control Method for Electro-Hydraulic Servo Actuators in Active Suspensions with Time Delay and Data Disturbances

by Hao Xiong, Dingxuan Zhao, Haiwu Zheng and Liqiang Zhao

Actuators 2026, 15(2), 130; https://doi.org/10.3390/act15020130 - 21 Feb 2026

Viewed by 540

Abstract

The Electro-Hydraulic Servo Actuator for Active Suspensions (ASEHSA) plays a decisive role in shaping the holistic performance of vehicle suspension systems through its dynamic response speed and control precision. However, achieving high-performance control of ASEHSA still faces challenges. On one hand, existing model-based [...] Read more.

The Electro-Hydraulic Servo Actuator for Active Suspensions (ASEHSA) plays a decisive role in shaping the holistic performance of vehicle suspension systems through its dynamic response speed and control precision. However, achieving high-performance control of ASEHSA still faces challenges. On one hand, existing model-based control methods are highly sensitive to parameter uncertainties and unmodeled nonlinear hydraulic dynamics, which can easily lead to reduced robustness in practical applications. On the other hand, traditional model-free strategies have limited time-delay compensation capabilities and often struggle to balance overshoot and settling time under delayed and disturbed conditions. To resolve this challenge, this study proposes an improved model-free adaptive control method that incorporates the differentiation of the tracking error (DE-IMFAC). Within the framework of traditional model-free adaptive control (MFAC), this approach reconfigures the time-delay term from an explicit form in the control law to implicit management, substantially mitigating the influence of time delays on system control performance. At the same time, by refining the performance criterion function and integrating a tracking error differentiation term together with dynamic weighting factors, the dynamic performance and adjustment flexibility of the controller are significantly enhanced. Additionally, by leveraging the characteristic equation of discrete autonomous systems and compression mapping theory, the BIBO stability of the DE-IMFAC control system and the monotonic convergence of the tracking error are rigorously established through theoretical analysis. Simulation and experimental results demonstrate that, compared with PID and traditional MFAC methods, DE-IMFAC significantly reduces integral absolute error, overshoot, settling time, and maximum position tracking error, while improving disturbance rejection capability. This approach does not depend on an accurate mathematical model of the ASEHSA system and maintains robust dynamic performance under complex operating environments characterized by time delays and data disturbances, providing a practical solution for ASEHSA and related industrial control systems. Full article

(This article belongs to the Special Issue Advanced Actuation and Control Technologies for Vehicle Driving Systems—2nd Edition)

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12 pages, 1268 KB

Open AccessArticle

Improved Model Reference Adaptive Disturbance Suppression Control for Marine Canned Magnetic Bearings

by Jiawang Pan, Hao Jiang, Zhenzhong Su, Qi Liu and Yajian Li

Actuators 2026, 15(2), 129; https://doi.org/10.3390/act15020129 - 20 Feb 2026

Viewed by 431

Abstract

To overcome the limitations of conventional control strategies in simultaneously suppressing external sway disturbances and internal parameter variations—induced by strong eddy current effects in marine canned magnetic bearings (MBs)—this paper introduces an improved model reference adaptive control (MRAC) method. First, electromagnetic force and [...] Read more.

To overcome the limitations of conventional control strategies in simultaneously suppressing external sway disturbances and internal parameter variations—induced by strong eddy current effects in marine canned magnetic bearings (MBs)—this paper introduces an improved model reference adaptive control (MRAC) method. First, electromagnetic force and dynamic models of the marine canned MBs are developed, taking into account eddy current effects and oscillatory motion. On this basis, a state observer is designed to estimate the system’s unknown dynamics. A predictive error term is formulated to capture the combined influence of model uncertainties and external disturbances. An adaptive law is then applied to compensate for these unknown dynamics and external disturbances. Moreover, the stability of the marine canned MBs system under the proposed improved MRAC scheme is rigorously analyzed using Lyapunov stability theory. Simulation results confirm the effectiveness of the algorithm, showing that, compared with conventional PID control, the improved MRAC approach reduces rotor vibration by more than 53%, significantly strengthening the disturbance rejection performance of marine canned MBs. Full article

(This article belongs to the Special Issue Magnetic Levitation and Actuator Integration: From Fundamental Research to Emerging Applications)

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21 pages, 2709 KB

Open AccessArticle

Adaptive Sliding Mode Control Based on a Peak-Suppression Extended State Observer for Angle Tracking in Steer-by-Wire Systems

by Guoqing Geng, Debang Sun, Jiantao Ma and Haoran Li

Actuators 2026, 15(2), 128; https://doi.org/10.3390/act15020128 - 19 Feb 2026

Viewed by 590

Abstract

To address the degradation of angle tracking performance in steer-by-wire (SBW) systems caused by external disturbances and parameter uncertainties, this paper proposes a composite control strategy integrating adaptive sliding mode control (ASMC) and a peak-suppression extended state observer (PSESO). Firstly, a novel sliding [...] Read more.

To address the degradation of angle tracking performance in steer-by-wire (SBW) systems caused by external disturbances and parameter uncertainties, this paper proposes a composite control strategy integrating adaptive sliding mode control (ASMC) and a peak-suppression extended state observer (PSESO). Firstly, a novel sliding mode reaching law is designed, which incorporates a dynamic adaptive gain function to achieve real-time adjustment of the control gain. This approach accelerates the reaching speed while effectively mitigating chattering. Secondly, to enhance the disturbance rejection capability of the system, a PSESO is developed to estimate the lumped disturbance in the SBW system in real time. By dynamically adjusting the observer bandwidth, the peak phenomenon in state estimation is suppressed, thereby avoiding saturation of the control signal. The disturbance estimate from the PSESO is then fed forward as a compensation term into the adaptive sliding mode (ASM) controller, forming a composite ASMC+PSESO controller that enables active compensation and suppression of disturbances. Finally, the proposed composite control strategy is validated through both simulations and experiments. Experimental results demonstrate that under sinusoidal signal tracking conditions, the proposed method reduces the maximum tracking error, the mean absolute error, and the integral absolute error by 64.4%, 74.2%, and 73.1%, respectively, compared to traditional sliding mode control (TSMC). These results fully underscore its superiority in angle tracking control and disturbance rejection for SBW systems. Full article

(This article belongs to the Special Issue Intelligent Actuation and Advanced Control for Robotics and Autonomous Systems)

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17 pages, 6738 KB

Open AccessArticle

An Origami-Inspired Pneumatic Elbow Exosuit with EMG-Based Active Rehabilitation Control

by Huaiyuan Chen and Weidong Chen

Actuators 2026, 15(2), 127; https://doi.org/10.3390/act15020127 - 17 Feb 2026

Viewed by 786

Abstract

A wearable elbow exosuit system has been proposed in this work, including the origami-inspired exosuit structure along with a portable air source and electromyography (EMG)-based active rehabilitation control method. The elbow exosuit is designed using an origami-inspired pneumatic actuator to meet the biomechanic [...] Read more.

A wearable elbow exosuit system has been proposed in this work, including the origami-inspired exosuit structure along with a portable air source and electromyography (EMG)-based active rehabilitation control method. The elbow exosuit is designed using an origami-inspired pneumatic actuator to meet the biomechanic requirements for elbow assistance. And a portable pneumatic source attached to the waist is also proposed to drive the elbow exosuit. On the basis of exosuit structure design, the active control with cascaded frame is then developed. For the active perspective, the EMG-based motion prediction is accomplished for the input of controller. To achieve real-time and accurate prediction, a simple feedforward neural network is utilized for a motion prediction model based on its fast training. To further reduce the size of the network, the features are extracted from the EMG and angle for the inputs, replacing the end-to-end method. Based on intention prediction, the cascaded controller subsequently completes position control, torque control and pressure servo control. Finally, through preliminary experiments on healthy participants, the elbow can be accurately predicted for the EMG-based method, and the assistance efficiency is verified through task scores and reduction in muscle activation. In summary, the proposed wearable exosuit can provide a reference for the design of wearable devices. Full article

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

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29 pages, 3033 KB

Open AccessArticle

Route-Aware AI-Assisted Fault Diagnosis and Fault-Tolerant Energy Management for Hybrid Hydrogen Electric Vehicles: SIL and PIL Validation

by Sihem Nasri, Aymen Mnassri, Nouha Mansouri, Abderezak Lashab, Juan C. Vasquez and Adnane Cherif

Actuators 2026, 15(2), 126; https://doi.org/10.3390/act15020126 - 16 Feb 2026

Viewed by 597

Abstract

This paper proposes a unified energy management, fault detection, and fault-tolerant control (EMS–FDI–FTC) framework for Hybrid Hydrogen Electric Vehicles (HHEVs) integrating a fuel cell (FC), battery (Bat), and supercapacitor (SC). While such multi-source architectures enable high-efficiency propulsion under dynamic driving conditions, actuator and [...] Read more.

This paper proposes a unified energy management, fault detection, and fault-tolerant control (EMS–FDI–FTC) framework for Hybrid Hydrogen Electric Vehicles (HHEVs) integrating a fuel cell (FC), battery (Bat), and supercapacitor (SC). While such multi-source architectures enable high-efficiency propulsion under dynamic driving conditions, actuator and state faults such as FC voltage sag, Bat internal resistance increase, and SC capacitance degradation can compromise safety, availability, and component lifetime. The proposed framework converts real-world GPS-recorded vehicle speed profiles into route-aware traction power demand and combines interpretable model-based indicators with an AI-based fault detection and classification module. Based on the diagnosis outcome, a fault-tolerant supervisory strategy performs online power reallocation among the FC, Bat, and SC while enforcing operational constraints. Validation is conducted in a MATLAB-based software-in-the-loop (SIL) environment using three urban driving routes collected from on-road measurements in Tunisia with injected ground-truth faults. The results demonstrate reliable fault classification performance and effective service continuity during fault intervals, supplying over 94% of the demanded energy across all routes, with energy-not-served remaining below 0.02 kWh. In addition, processor-in-the-loop (PIL) implementation on an STM32F407VG controller confirms real-time feasibility with a 10 Hz supervisory sampling rate and execution time margins compatible with embedded automotive deployment. Overall, the proposed closed-loop framework provides a practical route-aware diagnosis-to-control solution for robust and fault-resilient HHEV operation under realistic driving variability. All energy and efficiency indicators reported in this study are derived from control-oriented component models and are intended for consistent comparative evaluation across routes and operating scenarios, rather than absolute representation of a specific commercial vehicle. 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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24 pages, 10860 KB

Open AccessArticle

PostureSense: A Low-Cost Solution for Postural Monitoring

by Nicoletta Cinardi, Giuseppe Sutera, Dario Calogero Guastella and Giovanni Muscato

Actuators 2026, 15(2), 125; https://doi.org/10.3390/act15020125 - 16 Feb 2026

Viewed by 712

Abstract

Assistive devices in recent years have transitioned from a passive mode of operation to the integration of smart solutions that enable humans to interact with active and robotic platforms. The main problems in the evolution of this kind of device are accessibility in [...] Read more.

Assistive devices in recent years have transitioned from a passive mode of operation to the integration of smart solutions that enable humans to interact with active and robotic platforms. The main problems in the evolution of this kind of device are accessibility in terms of price and the functional limitations of the smart integrated solutions. This project proposes an armrest prototype for integration into smart walkers or wheelchairs that can detect the user’s intentions at a low development cost. The smart principle of operation is based on Hall-effect sensors, strategically positioned to measure the Center of Pressure (CoP) of the user’s forearm and to classify motor intention using machine learning algorithms such as Random Forest and Leave-One-Subject-Out (LOSO). The detection and correct classification of the user’s intention is a tool that can be integrated as a control system for both motorized and passive assistive devices. Full article

(This article belongs to the Special Issue Rehabilitation Robotics and Intelligent Assistive Devices)

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33 pages, 2460 KB

Open AccessReview

Redundant Robots for Work in Space—Literature Review

by Ivan Chavdarov, Bozhidar Naydenov, Borislava Kostova and Snezhana Kostova

Actuators 2026, 15(2), 124; https://doi.org/10.3390/act15020124 - 16 Feb 2026

Viewed by 1173

Abstract

Space robots operate in unconventional environments, which places specific demands on their mechanical, actuation, and control systems. They need to address a variety of challenges in future space exploitation and exploration, such as in-orbit deployment, active debris removal, or servicing operations. Using robots [...] Read more.

Space robots operate in unconventional environments, which places specific demands on their mechanical, actuation, and control systems. They need to address a variety of challenges in future space exploitation and exploration, such as in-orbit deployment, active debris removal, or servicing operations. Using robots for such applications presents a unique challenge, as a high level of autonomy is required, and the manipulator’s motion affects the position and orientation of the spacecraft. The article presents basic theoretical statements regarding redundancy in space robotics. Various methods for overcoming difficulties in designing, using, and controlling a space robot are considered. Specialized control algorithms based on the null space of the Jacobian matrix and zero reaction maneuvers (ZRMs) are discussed. The review is limited to space robots with one or more arms and does not include mobile and humanoid robots. Furthermore, the primary motion planning algorithms for these systems are evaluated. Redundant space robots are categorized based on their degrees of freedom, number of arms, operational efficiency, primary objectives, and application areas and the most commonly used algorithms for planning movements. The advantages and disadvantages of both redundant and hyper-redundant space robots are analyzed. The objective of this review is to provide a comprehensive overview of the current state and prospects for the development of redundant robots for operation in space conditions. Full article

(This article belongs to the Section Aerospace Actuators)

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15 pages, 3115 KB

Open AccessArticle

A Study on the Efficiency Matching of Energy-Weighted Regions in IPMSM Through Loading Ratio and Stator-Rotor Diameter Ratio Adjustment

by Su-Jin Song, Kan Akatsu, Dong-Woo Lee and Ho-Joon Lee

Actuators 2026, 15(2), 123; https://doi.org/10.3390/act15020123 - 15 Feb 2026

Viewed by 534

Abstract

This study proposes an electromagnetic design strategy to improve the energy efficiency of electric-vehicle (EV) traction motors by defining an operating region with high energy contribution using Urban Dynamometer Driving Schedule (UDDS) data and targeting efficiency improvement within that region. For distributed-winding (DW) [...] Read more.

This study proposes an electromagnetic design strategy to improve the energy efficiency of electric-vehicle (EV) traction motors by defining an operating region with high energy contribution using Urban Dynamometer Driving Schedule (UDDS) data and targeting efficiency improvement within that region. For distributed-winding (DW) and concentrated-winding (CW) IPMSM models, the stator-to-rotor diameter ratio varied, and the resulting change in the loading ratio was used as an indicator to evaluate loss and efficiency variations in the energy-weighted region of the efficiency map via two-dimensional finite element analysis (2D FEA). The results show that the losses within the weighted region decreased by up to 16.64% compared with the reference model, and the UDDS-cycle-based overall energy efficiency improved by up to 0.423%. These findings demonstrate that combining electromagnetic geometric design with driving-cycle data can serve as a practical metric for improving EV energy efficiency. Full article

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

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31 pages, 7717 KB

Open AccessArticle

A High-Performance AEFC Strategy with Intelligent Parameter Tuning for Magnetic Suspension Flywheel Battery

by Weiyu Zhang, Youpeng Chen, Xiaoyan Diao and Qianwen Xiang

Actuators 2026, 15(2), 122; https://doi.org/10.3390/act15020122 - 15 Feb 2026

Viewed by 555

Abstract

In order to reduce the influence of external radial disturbances on the control accuracy and stability of the vehicle magnetic suspension flywheel battery system during driving, and to further enhance the system’s disturbance rejection ability, this paper designs a control method based on [...] Read more.

In order to reduce the influence of external radial disturbances on the control accuracy and stability of the vehicle magnetic suspension flywheel battery system during driving, and to further enhance the system’s disturbance rejection ability, this paper designs a control method based on the Accelerated Engineering Fastest Controller (AEFC) and the improved differential optimization algorithm. A mathematical model of the flywheel battery system is established, and the AEFC scheme with engineering disturbance rejection is adopted in the control loop. The improved differential optimization algorithm is used to obtain the optimal control parameters of AEFC, and a multi-criteria optimization function combining tracking error and smoothness is established. The overall control scheme effectively integrates the characteristics of rapid tracking, interference suppression, and rapid parameter adjustment. The experimental results show that compared with the Engineering Fastest Controller (EFC), in the vehicle turning process, the AEFC controller can reduce the offset by 28% during vehicle driving, and compared with the traditional PID control, it can reduce the offset by 41.94%. In the process of vehicle uphill and speed change, the control effect of AEFC also has a significant improvement. Full article

(This article belongs to the Special Issue Magnetic Levitation and Actuator Integration: From Fundamental Research to Emerging Applications)

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15 pages, 937 KB

Open AccessArticle

An Improved MAPPO for Multi-Surface Vessel Collaboration

by Guangyu Wang, Feng Tian and Chengcheng Ren

Actuators 2026, 15(2), 121; https://doi.org/10.3390/act15020121 - 14 Feb 2026

Viewed by 821

Abstract

Collaborative control of multiple surface vessels remains a significant challenge in autonomous maritime operations, particularly within environments characterized by sparse rewards. Conventional Multi-Agent Proximal Policy Optimization (MAPPO) often suffers from inefficient credit assignment and slow convergence in such scenarios. To address these limitations, [...] Read more.

Collaborative control of multiple surface vessels remains a significant challenge in autonomous maritime operations, particularly within environments characterized by sparse rewards. Conventional Multi-Agent Proximal Policy Optimization (MAPPO) often suffers from inefficient credit assignment and slow convergence in such scenarios. To address these limitations, this paper proposes an enhanced MAPPO framework that integrates a counterfactual baseline—derived from Counterfactual Multi-Agent Policy Gradients (CMAPG)—into the Generalized Advantage Estimation (GAE) formulation. Furthermore, a Prioritized Experience Replay (PER) mechanism with importance sampling is incorporated to improve sample efficiency. The counterfactual baseline is necessary to provide precise, agent-specific learning signals within the on-policy paradigm, directly tackling the credit assignment problem. The PER mechanism, carefully adapted with importance sampling, is essential to break the sample-inefficiency barrier by strategically reusing valuable past experiences without compromising stability. This synergistic approach refines credit assignment by isolating individual contributions and maximizes the utility of valuable historical experiences. Simulation results and comparisons validate the enhanced control performance of the proposed controller. Full article

(This article belongs to the Special Issue Feature Papers in Actuators for Surface Vehicles)

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25 pages, 2116 KB

Open AccessArticle

Structural Design and Modeling Analysis of an Active Magnetic Levitation Vibration Isolation System

by Chunhui Dai, Cuicui Huang, Xinyu Liu and Xiaolong Li

Actuators 2026, 15(2), 120; https://doi.org/10.3390/act15020120 - 14 Feb 2026

Cited by 1 | Viewed by 698

Abstract

This paper addresses the stringent requirements of high-precision equipment for broadband, contactless active vibration isolation by tackling three key research gaps: the lack of an integrated design deeply coupling vertical and lateral subsystems, the absence of explicit characterization of the base-to-load vibration transmission [...] Read more.

This paper addresses the stringent requirements of high-precision equipment for broadband, contactless active vibration isolation by tackling three key research gaps: the lack of an integrated design deeply coupling vertical and lateral subsystems, the absence of explicit characterization of the base-to-load vibration transmission chain in dynamic models, and the disconnect between theory and application due to spatial sensor–actuator mismatch. To bridge these gaps, a novel five-degree-of-freedom active magnetic levitation vibration isolation system is proposed. Its core contributions are threefold. First, an electromagnetic-structure co-design method based on the equal magnetic reluctance principle is introduced, enabling a globally optimized, integrated actuator layout that maximizes force density within spatial constraints. Second, a dynamic model incorporating explicit base kinematic excitation is established, clearly revealing the complete physical mechanism of vibration transmission through the suspension gap and providing an accurate foundation for model-based control. Third, a coordinate reconstruction control model is constructed, which transforms the ideal center-of-mass-based dynamics into a design model using only measurable gap signals via systematic coordinate transformations, thereby fundamentally eliminating control deviations from physical spatial mismatch. This work provides a comprehensive theoretical framework and solution for next-generation high-performance active vibration isolation platforms, encompassing integrated design, precise modeling, and engineering implementation. Full article

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

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22 pages, 3319 KB

Open AccessReview

Research on Key Technologies of Low-Energy-Consumption Magnetic Suspension Flywheel Battery Systems

by Zhibin Li, Xiaoyan Diao, Qianwen Xiang and Weiyu Zhang

Actuators 2026, 15(2), 119; https://doi.org/10.3390/act15020119 - 14 Feb 2026

Viewed by 943

Abstract

As an emerging physical energy storage technology, the magnetic suspension flywheel battery boasts prominent advantages such as high working efficiency, long service life, and short charging time. However, improving the energy conversion efficiency of magnetic suspension flywheel battery systems and reducing their overall [...] Read more.

As an emerging physical energy storage technology, the magnetic suspension flywheel battery boasts prominent advantages such as high working efficiency, long service life, and short charging time. However, improving the energy conversion efficiency of magnetic suspension flywheel battery systems and reducing their overall energy loss have long been critical bottleneck technologies that urgently need to be addressed for practical applications. To promote China’s green and low-carbon energy transition and accelerate the achievement of the “double carbon” goals, this paper summarizes two core components of flywheel battery systems—magnetic bearings and flywheel motors—along with two key technologies: topological structure and control strategy, based on numerous cutting-edge studies. Subsequently, focusing on further reducing the energy consumption of flywheel energy storage systems, technical prospects are extended from aspects including system material selection and intelligent integrated control, aiming to provide research directions for the low-energy-consumption operation of flywheel battery systems. Full article

(This article belongs to the Special Issue Magnetic Levitation and Actuator Integration: From Fundamental Research to Emerging Applications)

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19 pages, 4021 KB

Open AccessArticle

Research on Levitation Control of a Two-Degree-of-Freedom System Based on IWOA-ISMC

by Ziyang Hao, Linjie Hao, Pengfei Liu, Ruichen Wang and Meiqi Wang

Actuators 2026, 15(2), 118; https://doi.org/10.3390/act15020118 - 14 Feb 2026

Viewed by 417

Abstract

Electromagnetic levitation control is a core technology for ensuring the stable operation of maglev trains. To enhance the disturbance rejection capability and stability of the levitation system, an IWOA-ISMC control strategy is proposed in this paper. First, a single-electromagnet levitation model with two [...] Read more.

Electromagnetic levitation control is a core technology for ensuring the stable operation of maglev trains. To enhance the disturbance rejection capability and stability of the levitation system, an IWOA-ISMC control strategy is proposed in this paper. First, a single-electromagnet levitation model with two degrees of freedom is established, in which the effects of spring stiffness and damping are taken into account. Based on this model, an integral sliding mode controller (ISMC) is designed. However, manual parameter tuning based on engineering experience makes it difficult to obtain an optimal parameter combination, and inappropriate controller parameters may lead to significant performance degradation. To address this issue, an improved whale optimization algorithm (IWOA) is introduced to globally optimize the key parameters of the ISMC, resulting in an IWOA-ISMC tailored to the proposed model. Comparative simulations under track irregularity conditions and sudden force disturbances induced by track irregularities are conducted. The results demonstrate that, compared with ISMC, PID, and backstepping controllers, the proposed IWOA-ISMC approach exhibits superior disturbance rejection performance and robustness. Full article

(This article belongs to the Special Issue Magnetic Levitation and Actuator Integration: From Fundamental Research to Emerging Applications)

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22 pages, 5466 KB

Open AccessArticle

Adaptive Longitudinal–Lateral Coordinated Control of Distributed Drive Vehicles Under Unknown Road Conditions

by Jiansen Yang, Zhongliang Han, Zhiguo Zhang, Xuewei Wang, Fan Bai and Yan Wang

Actuators 2026, 15(2), 117; https://doi.org/10.3390/act15020117 - 13 Feb 2026

Viewed by 482

Abstract

Distributed drive vehicles provide enhanced actuation flexibility, making longitudinal–lateral coordinated stability control essential for improving vehicle handling and safety under complex driving conditions. Nevertheless, the existing coordinated control strategies commonly employ stability reference models with fixed tire–road friction coefficients, which restrict their adaptability [...] Read more.

Distributed drive vehicles provide enhanced actuation flexibility, making longitudinal–lateral coordinated stability control essential for improving vehicle handling and safety under complex driving conditions. Nevertheless, the existing coordinated control strategies commonly employ stability reference models with fixed tire–road friction coefficients, which restrict their adaptability to time-varying adhesion environments. In addition, conventional sliding mode-based lateral stability controllers may exhibit limited performance when confronted with strong nonlinear coupling and external disturbances. To address these issues, this paper proposes an integrated longitudinal–lateral coordinated stability control framework for distributed drive vehicles. A dual unscented Kalman filter-based estimator is developed to identify the tire–road friction coefficients and construct a friction-adaptive reference model for yaw rate and sideslip angle. An adaptive fractional power speed controller with resistance compensation is designed to generate the total longitudinal driving torque, while an adaptive neural sliding mode controller produces the corrective yaw moment for lateral stability enhancement. Furthermore, a pseudoinverse-based torque distribution strategy is employed to allocate the longitudinal torque and yaw moment to individual wheels. Simulation results demonstrate that the proposed framework significantly improves vehicle stability and tracking accuracy compared with conventional control methods under varying road conditions. Full article

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

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26 pages, 23010 KB

Open AccessArticle

Risk-Aware Adaptive Safety Margins for Model Predictive Control with Orientation–Motion Coupled Barrier Functions in Dynamic Environments

by Nuo Xu, Zhong Yang, Haoze Zhuo, Lvwei Liao, Yaoyu Sui and Naifeng He

Actuators 2026, 15(2), 116; https://doi.org/10.3390/act15020116 - 13 Feb 2026

Viewed by 1361

Abstract

Safe navigation in dynamic environments remains challenging because classical distance-based constraints ignore the coupling between a robot’s translational motion and attitude dynamics, and fixed safety margins are either over-conservative or risky under varying uncertainty and approach speed. This paper presents a Risk-Aware Model [...] Read more.

Safe navigation in dynamic environments remains challenging because classical distance-based constraints ignore the coupling between a robot’s translational motion and attitude dynamics, and fixed safety margins are either over-conservative or risky under varying uncertainty and approach speed. This paper presents a Risk-Aware Model Predictive Control (RA-MPC) framework that addresses both limitations through two integrated components. First, we introduce Orientation–Motion Coupled Control Barrier Functions (O-MCBFs) that enforce unified safety constraints linking collision avoidance with attitude stability limits, preventing dangerous pose configurations during dynamic obstacle avoidance. Second, we develop Risk-Aware Adaptive Margins (RAAMs) that compute time-varying safety buffers based on relative velocity, robot braking capability, and prediction uncertainty, enabling context-dependent safety–efficiency trade-offs without manual parameter tuning. The proposed method integrates these components into a quadratic programming formulation within MPC, ensuring real-time computational tractability. Experimental results demonstrate higher success rates, smoother trajectories, and improved progress toward the goal, with no observed safety violations under the tested conditions. These findings indicate that coupling pose-space safety with risk-adaptive margins provides a principled and practical path to safe and efficient navigation in dynamic scenes. Full article

(This article belongs to the Section Actuators for Robotics)

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23 pages, 5922 KB

Open AccessArticle

Comparative Study of Stator Electrically Excited Machines with and Without Dual-Armature Windings

by Hui Wen, Bingtuo Chen, Wenting Wang, Yufei Wang and Xiao Qu

Actuators 2026, 15(2), 115; https://doi.org/10.3390/act15020115 - 13 Feb 2026

Cited by 1 | Viewed by 548

Abstract

To meet the demand for high torque density in applications such as actuators, this paper investigates the use of dual-armature (DA) windings on both stator and rotor to enhance torque performance for stator electrically excited machines. A systematic comparison is conducted among four [...] Read more.

To meet the demand for high torque density in applications such as actuators, this paper investigates the use of dual-armature (DA) windings on both stator and rotor to enhance torque performance for stator electrically excited machines. A systematic comparison is conducted among four topologies, namely the conventional flux-switching electrically excited (FSEE) and variable flux reluctance (VFR) machines, as well as their DA counterparts. All machines are optimized under the same copper loss and torque ripple constraints to ensure a fair comparison. The results show that the FSEE machine delivers approximately 49% higher torque than the VFR machine, attributed to its higher stator back-EMF. By integrating the rotor armature winding that fully utilizes the rotor space, the DA-FSEE and DA-VFR machines achieve substantial torque improvements of 81% and 163%, respectively. While the DA-VFR machine shows the most pronounced torque enhancement, the DA-FSEE machine provides the highest-torque output. Benefiting from the improved torque performance, the DA-FSEE and DA-VFR machines also demonstrate 10–20% higher efficiency over their counterparts within a typical speed range. Furthermore, sensitivity analysis of key design parameters reveals that the split ratio has the most profound influence on torque output for all the machines, followed by the stator tooth width. In the DA machines, the rotor yoke thickness emerges as a consistently important factor for achieving high torque performance. These key findings provide valuable guidance for the optimal selection and detailed design of high-performance electrically excited machines in engineering practice. Full article

(This article belongs to the Special Issue Next-Generation Electric Machine Design and Control for Sustainable Mobility)

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21 pages, 1113 KB

Open AccessArticle

A Dynamic Weight Deep Reinforcement Learning Approach for SDN Multi-Objective Optimization with Actuator Integration

by Jian Wang, Zhongxu Liu, Xianzhi Cao and Liusong Yang

Actuators 2026, 15(2), 114; https://doi.org/10.3390/act15020114 - 12 Feb 2026

Cited by 1 | Viewed by 827

Abstract

In recent years, the surge in network traffic has led to a substantial increase in energy consumption, making the construction of green and energy-efficient networks a critical challenge in the field of communications. Software-Defined Networking (SDN), with its centralized control characteristic, provides a [...] Read more.

In recent years, the surge in network traffic has led to a substantial increase in energy consumption, making the construction of green and energy-efficient networks a critical challenge in the field of communications. Software-Defined Networking (SDN), with its centralized control characteristic, provides a new paradigm for the collaborative scheduling of actuators. However, traditional distributed network architectures lack global regulation capabilities, resulting in low resource utilization. Moreover, existing SDN traffic management methods mostly adopt fixed-weight reward functions, which are difficult to adapt to the dynamic fluctuation of network traffic and device heterogeneity, failing to meet the real-time and stability requirements of actuators in control scenarios. To address these issues, this study proposes a Dynamic Weight Generation Deep Q-Network (DWG-DQN) framework. By integrating a Long Short-Term Memory (LSTM) network with the SDN actuator scheduling mechanism, the system dynamically generates adaptive weight vectors, enabling real-time collaborative optimization of energy consumption, load balancing, and bandwidth utilization. Experimental results demonstrate that in fat-tree topology experiments, the proposed method achieves a 12.23% increase in average reward, a 33.93% reduction in energy consumption, a 31.12% improvement in load balancing, and a 24.03% enhancement in bandwidth utilization. Compared with fixed-weight method, it consistently outperforms in key performance indicators. The dynamic weight generation mechanism effectively solves the multi-objective optimization problem of actuators in dynamic network environments, offering a viable solution for the intelligent scheduling of actuators in SDN-based green traffic management. Full article

(This article belongs to the Section Control Systems)

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26 pages, 2752 KB

Open AccessArticle

Force Control of an Active Suspension Hydraulic Servo System Based on BSO-Optimized ESO-Based SMC

by Yunshi Wu, Donghai Su, Yuyan Wei and Jingchao Sun

Actuators 2026, 15(2), 113; https://doi.org/10.3390/act15020113 - 12 Feb 2026

Viewed by 545

Abstract

To mitigate the significant impact of system nonlinearities, time-varying parameters, and external load disturbances on the output force of hydraulic servo systems in active hydraulic suspensions for engineering vehicles, this study proposes a beetle swarm optimization (BSO)-optimized extended state observer (ESO)-based sliding mode [...] Read more.

To mitigate the significant impact of system nonlinearities, time-varying parameters, and external load disturbances on the output force of hydraulic servo systems in active hydraulic suspensions for engineering vehicles, this study proposes a beetle swarm optimization (BSO)-optimized extended state observer (ESO)-based sliding mode control (SMC) strategy. A comprehensive mathematical model of the hydraulic servo system is established, and an ESO-based SMC controller is designed, taking into account the coupled effects of chamber pressure dynamics and external loads on the uncertain output force. The stability of the closed-loop system is rigorously analyzed and verified using Lyapunov stability theory. The effectiveness of the proposed control strategy is verified through both numerical simulations and experimental tests. For step inputs of 5000 N and 8000 N, overshoot is significantly reduced compared with the conventional proportional–integral–derivative control and the standard extended state observer-based sliding mode control, while the settling time is shortened by more than 65% in simulations and up to 75% in experiments. Under sinusoidal force excitations at frequencies of 0.5 Hz, 1 Hz, and 2 Hz, the maximum tracking error, mean error, and standard deviation of the tracking error are substantially reduced, with the maximum error reduction exceeding 90%. These results demonstrate that the proposed method achieves high-precision force tracking under external disturbances and pronounced system uncertainties, providing an effective solution for force control of hydraulic servo systems in active suspension applications for engineering vehicles. Full article

(This article belongs to the Section Control Systems)

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17 pages, 6305 KB

Open AccessArticle

A Collaborative Dynamic Transit Scheduling Method Integrating Timetable Adjustment and Control-Oriented Trajectory Guidance

by Kunmin Teng, Haiqing Liu and Xiao Lu

Actuators 2026, 15(2), 112; https://doi.org/10.3390/act15020112 - 12 Feb 2026

Viewed by 675

Abstract

Dynamic scheduling of public transit is crucial for enhancing comprehensive operational benefits such as service quality and operating costs. However, uncertain passenger demands and the uncontrolled block effects of signalized intersections can lead to timetable deviation, significantly affecting scheduling efficiency. This paper proposes [...] Read more.

Dynamic scheduling of public transit is crucial for enhancing comprehensive operational benefits such as service quality and operating costs. However, uncertain passenger demands and the uncontrolled block effects of signalized intersections can lead to timetable deviation, significantly affecting scheduling efficiency. This paper proposes a collaborative dynamic transit scheduling method to mitigate the negative coupling effect. A passenger demand-aware dynamic timetable scheduling strategy is developed to improve timetable adherence and operational homogeneity. A control-oriented trajectory guidance strategy is established to enhance the effectiveness of the timetable scheduling strategy and reduce the operating costs considering the blocking effects of signalized intersections and transit actuator constraints. Integrating the two strategies, a collaborative optimization framework using a multi-objective nonlinear programming model is constructed to present an optimal comprehensive benefit scheduling scheme. Simulation results demonstrate that, compared to traditional methods within the same simulation scenarios, the proposed method improves the performance of operational homogeneity, timetable adherence, and energy efficiency by up to 67.6%, 71.03%, and 27.5%, respectively. In addition, it also enables the transit to pass through multiple signalized intersections without stopping, significantly enhancing the transit’s operational stability and operating cost. Full article

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

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16 pages, 2975 KB

Open AccessReview

A Review of Passive Linear Gravity Compensation Mechanisms

by Kyung-su Park and Kyung-min Lee

Actuators 2026, 15(2), 111; https://doi.org/10.3390/act15020111 - 11 Feb 2026

Cited by 1 | Viewed by 1138

Abstract

This study presents a review of passive linear gravity compensation (GC) mechanisms. Linear GC is defined as the realization of a displacement-independent constant upward force along a vertical axis to balance the gravitational load over the entire stroke. This paper focuses on passive [...] Read more.

This study presents a review of passive linear gravity compensation (GC) mechanisms. Linear GC is defined as the realization of a displacement-independent constant upward force along a vertical axis to balance the gravitational load over the entire stroke. This paper focuses on passive systems that counteract gravity solely through mechanical or magnetic energy storage elements, without relying on external power sources. The main energy sources in passive systems—springs, permanent magnets, counterweights, and fluid pressure—are surveyed with emphasis on their ability to generate a constant force. Representative spring-based constant-force mechanisms, cam–spring linkages, and quasi-zero-stiffness magnetic gravity compensators are summarized, together with their applications in vibration isolation systems. Finally, reported performance data are compiled to outline the practical operating envelope of passive linear GC in terms of force level, stroke, and equivalent stiffness. This review reveals that permanent-magnet-based approaches are advantageous for short-stroke, high-precision applications, whereas spring-based mechanisms offer superior suitability for long-stroke requirements due to their greater design flexibility. Consequently, this review provides a strategic selection guideline based on the inherent trade-offs of energy-storage elements to meet specific application requirements. Full article

(This article belongs to the Section Actuators for Robotics)

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19 pages, 1679 KB

Open AccessArticle

Time-Varying Formation Tracking Control of Linear Multi-Agent Systems with Magnitude and Rate Saturation and Unknown Disturbances

by Pengyuan Li, Zhongzheng Li and Ke Wang

Actuators 2026, 15(2), 110; https://doi.org/10.3390/act15020110 - 9 Feb 2026

Viewed by 580

Abstract

In this paper, we study the leader-following time-varying formation (TVF) tracking control of general linear multi-agent systems (MASs) with nonzero control input of the leader, and the followers which have magnitude and rate saturation (MRS) and unknown disturbances. Under the assumption that only [...] Read more.

In this paper, we study the leader-following time-varying formation (TVF) tracking control of general linear multi-agent systems (MASs) with nonzero control input of the leader, and the followers which have magnitude and rate saturation (MRS) and unknown disturbances. Under the assumption that only the followers connecting to the leader have access to the leader’s input and state, an output feedback controller incorporating a distributed extended state observer (ESO) is developed to ensure the asymptotic convergence of the formation errors without input saturation. Then, a saturation model is inserted to each follower’s dynamics to constrain the magnitude and rate of the control input, with consideration of MRS. Anti-windup protection loops are applied to compensate for the saturated signals to improve the closed-loop performance. Finally, the theoretical findings are demonstrated via a series of numerical simulations. Full article

(This article belongs to the Section Control Systems)

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26 pages, 13257 KB

Open AccessArticle

Multi-Scale Feature Enhancement for Gearbox Fault Diagnosis Under Variable Operating Conditions

by Xianping Zeng, Chaoqi Jiang, Yanpeng Wu, Jinmin Peng and Yihan Wang

Actuators 2026, 15(2), 109; https://doi.org/10.3390/act15020109 - 9 Feb 2026

Viewed by 618

Abstract

Effective and intelligent fault diagnosis is essential for ensuring the operational safety and reliability of gearbox systems. In practical engineering environments, however, weak fault-related features are often obscured by strong background noise, pronounced nonstationarity, and time-varying operating conditions, which significantly degrade the performance [...] Read more.

Effective and intelligent fault diagnosis is essential for ensuring the operational safety and reliability of gearbox systems. In practical engineering environments, however, weak fault-related features are often obscured by strong background noise, pronounced nonstationarity, and time-varying operating conditions, which significantly degrade the performance of conventional feature extraction techniques. To address these challenges, this paper proposes an adaptive feature extraction approach that integrates the complementary advantages of variational mode decomposition (VMD), Teager energy operator (TEO), and multi-scale permutation entropy (MPE) to enhance the characterization of weak and transient fault signatures. Vibration signals associated with different fault conditions are first adaptively decomposed into a series of intrinsic mode functions (IMFs) using VMD, enabling the effective separation of fault-sensitive components and enrichment of fault-related information. Subsequently, an enhanced multi-scale permutation entropy (EMPE) method is developed to emphasize transient impulsive characteristics and capture fault-induced complexity variations across multiple temporal scales. By jointly exploiting instantaneous energy modulation and multi-scale dynamical complexity analysis, the proposed approach exhibits improved sensitivity to weak fault signatures and enhanced robustness against variable operating conditions. The effectiveness and generalization capabilities of the proposed framework are validated using three experimental datasets involving gearboxes and rolling bearings under diverse operating conditions. Comparative results demonstrate that the proposed method outperforms conventional entropy-based approaches in terms of fault feature separability and diagnostic performance, highlighting its potential for practical condition monitoring and fault diagnosis of rotating machinery. Full article

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

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26 pages, 8590 KB

Open AccessArticle

Anti-Disturbance Trajectory Tracking Control of Large Space Flexible Truss by Four Space Robots

by Luyao Li, Zhengtao Wei and Weidong Chen

Actuators 2026, 15(2), 108; https://doi.org/10.3390/act15020108 - 8 Feb 2026

Viewed by 476

Abstract

This paper addresses the high-precision transportation control of a large space flexible truss using four space robots, with a focus on dynamic modeling and control strategy design. The system’s dynamic model is derived based on Kane’s method, which facilitates efficient modeling of the [...] Read more.

This paper addresses the high-precision transportation control of a large space flexible truss using four space robots, with a focus on dynamic modeling and control strategy design. The system’s dynamic model is derived based on Kane’s method, which facilitates efficient modeling of the complicated rigid–flexible dynamics. Considering the truss’s flexible vibration as a key disturbance source, a nonlinear disturbance observer (NDO) is designed to achieve effective disturbance estimation. Then, to ensure high-precision trajectory tracking of such a complicated dynamics system, an integral sliding mode control (ISMC) strategy is developed based on NDO. Furthermore, leveraging the system’s actuator redundancy, the actuator inputs are weighted and allocated by accounting for individual actuator performance, which enhances the operational reliability. The effectiveness of the proposed control strategy is verified through theoretical analysis and numerical simulations. Full article

(This article belongs to the Section Aerospace Actuators)

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29 pages, 7055 KB

Open AccessArticle

Control of Powered Ankle–Foot Prostheses on Compliant Terrain: A Quantitative Approach to Stability Enhancement

by Chrysostomos Karakasis, Camryn Scully, Robert Salati and Panagiotis Artemiadis

Actuators 2026, 15(2), 107; https://doi.org/10.3390/act15020107 - 7 Feb 2026

Viewed by 664

Abstract

Walking on compliant terrain presents a substantial challenge for individuals with lower-limb amputation, further elevating their already high risk of falling. While powered ankle–foot prostheses have demonstrated adaptability across speeds and rigid terrains, control strategies optimized for soft or compliant surfaces remain underexplored. [...] Read more.

Walking on compliant terrain presents a substantial challenge for individuals with lower-limb amputation, further elevating their already high risk of falling. While powered ankle–foot prostheses have demonstrated adaptability across speeds and rigid terrains, control strategies optimized for soft or compliant surfaces remain underexplored. This work experimentally validates an admittance-based control strategy that dynamically adjusts the quasi-stiffness of powered prostheses to enhance gait stability on compliant ground. Human subject experiments were conducted with three healthy individuals walking on two bilaterally compliant surfaces with ground stiffness values of 63 and

25 \frac{kN}{m}

, representative of real-world soft environments. Controller performance was quantified using phase portraits and two walking stability metrics, offering a direct assessment of fall risk. Compared to a standard phase-variable controller developed for rigid terrain, the proposed admittance controller reduced short-term maximum Lyapunov exponents by an average of 7%, indicating improved local dynamic stability. These results support the potential of adaptive prostheses control to enhance gait stability on compliant surfaces, contributing to the development of more robust human–prosthesis interaction. Full article

(This article belongs to the Special Issue Actuation, Biomechanics, and Control Strategies of Prosthetics, Orthotics, and Exoskeletons)

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14 pages, 2237 KB

Open AccessArticle

Dynamic Parameter Identification of a Hip Exoskeleton Using RLS-GA

by Wentao Sheng, Yunxia Cao, Farzan Ghalichi, Li Ding and Tianyu Gao

Actuators 2026, 15(2), 106; https://doi.org/10.3390/act15020106 - 6 Feb 2026

Viewed by 607

Abstract

Lower-limb exoskeletons require accurate dynamic models to achieve stable and compliant human–robot interactions. However, least-squares-based identification often relies on demanding experiments and may yield limited accuracy for exoskeletons with non-standard structures and actuator-induced uncertainties. This paper proposes a two-stage dynamic parameter identification method [...] Read more.

Lower-limb exoskeletons require accurate dynamic models to achieve stable and compliant human–robot interactions. However, least-squares-based identification often relies on demanding experiments and may yield limited accuracy for exoskeletons with non-standard structures and actuator-induced uncertainties. This paper proposes a two-stage dynamic parameter identification method that integrates recursive least squares (RLS) and a genetic algorithm (GA), denoted as RLS-GA. RLS is first executed offline to estimate the variation ranges of the inertial parameter vector and to construct a finite, physically meaningful search space. GA then refines the parameters within these bounds by minimizing the regression residual norm. Experiments on a hip exoskeleton show that RLS-GA achieves higher identification accuracy than LS and unconstrained GA, while converging faster than GA under identical conditions. Full article

(This article belongs to the Section Actuators for Robotics)

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15 pages, 7694 KB

Open AccessArticle

Fault-Tolerant Control of Quadrotors with Actuator Faults: Experimental Verification of a Backstepping-Based Adaptive Controller

by Yasuyuki Satoh and Anan Tabata

Actuators 2026, 15(2), 105; https://doi.org/10.3390/act15020105 - 6 Feb 2026

Cited by 1 | Viewed by 760

Abstract

In many unmanned aerial vehicle (UAV) applications, achieving stable flight despite actuator failures is crucial. Among the many existing fault-tolerant control (FTC) methods, adaptive control is a practical approach. In this article, we present experimental verification of a backstepping-based adaptive fault-tolerant controller previously [...] Read more.

In many unmanned aerial vehicle (UAV) applications, achieving stable flight despite actuator failures is crucial. Among the many existing fault-tolerant control (FTC) methods, adaptive control is a practical approach. In this article, we present experimental verification of a backstepping-based adaptive fault-tolerant controller previously proposed by the authors. As the first step of the experimental verification, we focus on the attitude-loop control of the quadrotor. We construct a quadrotor testbed integrating a self-developed flight controller. After parameter identification, we implement the adaptive fault-tolerant controller on the quadrotor. Finally, real-time experiments on attitude stabilization following actuator faults are conducted. As a result, we confirmed that the controller can be implemented and can stabilize the attitude even in the presence of multi-actuator faults. Full article

(This article belongs to the Special Issue Adaptive Fault-Tolerant Control Strategies for Uncertain Nonlinear Systems: Mitigating Actuator Faults)

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23 pages, 9435 KB

Open AccessArticle

Triplet-Fusion Self-Attention-Enhanced Pyramidal Convolutional Neural Network for Surgical Robot Kinematic Solution

by Tiecheng Su, Lu Liang, Mingzhang Pan, Changcheng Fu, Hengqiu Huang, Jing’ao Li and Ke Liang

Actuators 2026, 15(2), 104; https://doi.org/10.3390/act15020104 - 5 Feb 2026

Viewed by 552

Abstract

Surgical robots are increasingly utilized in medicine for their reliability and convenience. An accurate kinematic model is essential for precise robot control and enhanced surgical safety. However, the high nonlinearity and computational complexity of kinematics pose significant challenges to traditional numerical methods. This [...] Read more.

Surgical robots are increasingly utilized in medicine for their reliability and convenience. An accurate kinematic model is essential for precise robot control and enhanced surgical safety. However, the high nonlinearity and computational complexity of kinematics pose significant challenges to traditional numerical methods. This study designs a surgical robotic arm and establishes the motion mapping relationship between the joint space and the end-effector workspace. Subsequently, a hybrid kinematic estimation model based on deep pyramid convolutional neural network (DPCNN) is proposed, which integrates data sampling and an attention mechanism to improve computational accuracy. The Latin hypercube sampling technique is used to improve the uniformity of dataset sampling, and the triplet-fusion self-attention mechanism (TFSAM) is employed for multi-scale feature information. Experimental results show that the TFSAM-DPCNN model achieves coefficient of determination (R²) values exceeding 0.99 across all testing scenarios. Compared with other models, the proposed model reduced the root mean square error (RMSE) by up to 81.34%, exhibiting superior performance. Furthermore, the developed 3D simulation platform validates the effectiveness of the proposed model. This study offers a robust solution for multi-degree-of-freedom robot modeling, with potential applications across a range of robotic motion control systems. Full article

(This article belongs to the Section Actuators for Robotics)

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15 pages, 3071 KB

Open AccessArticle

In-Plane Vibration-Driven Miniature Piezoelectric Motor: Design, Modeling, and Experimental Characterization

by Yunlai Shi, Cong Tang, Junhan Wang and Ruijun Wang

Actuators 2026, 15(2), 103; https://doi.org/10.3390/act15020103 - 5 Feb 2026

Viewed by 1222

Abstract

High-speed miniature rotary actuators are critical components in compact, high-performance systems. However, conventional electromagnetic micromotors face a prominent trade-off between miniaturization and output performance, which restricts their applicability in highly integrated devices. To address this challenge, a novel high-speed rotary piezoelectric ultrasonic motor [...] Read more.

High-speed miniature rotary actuators are critical components in compact, high-performance systems. However, conventional electromagnetic micromotors face a prominent trade-off between miniaturization and output performance, which restricts their applicability in highly integrated devices. To address this challenge, a novel high-speed rotary piezoelectric ultrasonic motor is proposed. The proposed motor consists of a titanium alloy metal body with offset driving teeth, piezoelectric ceramic plates, two conical rotors, a compression spring, an output shaft, and a fastening sleeve. Four PZT-8 plates are bonded to the periphery of the metal body and excited to generate in-plane bending vibration modes; these vibrations are then transformed into unidirectional rotary motion through the periodic contraction and expansion of the offset driving teeth and frictional contact with the rotors. The operating principle and structural parameters of the proposed motor were analyzed and optimized using finite element analysis (FEA), including modal, harmonic response, and transient analyses. A prototype was fabricated to evaluate its mechanical properties. The stator has a compact size of 12 mm × 12 mm × 4 mm and a mass of 2.3 g. Experimental results demonstrate that under an excitation voltage of 350 V_p-p at the resonant frequency of 28.6 kHz, the motor achieves a maximum rotational speed of 4720 rpm and a maximum stall torque of 0.36 mN·m. With its simple structure, compact size, lightweight design, and excellent output performance, the proposed ultrasonic motor provides a solution for compact high-speed rotary actuation. Full article

(This article belongs to the Section Actuator Materials)

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25 pages, 7886 KB

Open AccessArticle

Wind Tunnel Tests on a Piezo-Based Ice Protection System

by Luigi Mangiacrapa, Thorsten Klaas, Lorenzo Pellone, Filomena Piscitelli, Nadine Rehfeld, Giuseppe Mingione, Francesco Amoroso, Antonio Concilio and Salvatore Ameduri

Actuators 2026, 15(2), 102; https://doi.org/10.3390/act15020102 - 5 Feb 2026

Viewed by 709

Abstract

The requirements of the upcoming aircraft generation based on hybrid or electric propulsion discourage the use of Ice Protection Systems (IPSs) based on hot-air spilled from engine or demanding a large consumption of electrical power. In line with this need, a low-power IPS [...] Read more.

The requirements of the upcoming aircraft generation based on hybrid or electric propulsion discourage the use of Ice Protection Systems (IPSs) based on hot-air spilled from engine or demanding a large consumption of electrical power. In line with this need, a low-power IPS based on piezoelectric (PZT) technology is investigated in the current article. Its main objective is to protect an aerodynamic surface by removing ice accretions (de-icing). The idea at the basis of the concept is to drive mechanical waves at the interface between the skin and the ice layer to cause the breaking and the detachment. Moving from an assessed layout and numerical simulations providing the most effective design configuration, dedicated small-scale airfoil demonstrators (NACA 0012 with a chord of 310 mm and a span of 150 mm) were manufactured, with the aim of testing the technology within the representative environment of the IFAM Icing Wind Tunnel (IWT). The test results showed, for power consumption of 4.4 kW/m², ice detachment levels -based on the ice-covered area- between 40 and 50% at −10 °C, about 40% at −20 °C, and a maximum of 15% at −4 °C. The results highlighted the impact of some specific parameters (environmental temperature, skin, and ice thickness) on the effectiveness of the IPS. Full article

(This article belongs to the Special Issue The Impact of Smart Structures in Contemporary and Future Aerospace Scenarios)

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34 pages, 4019 KB

Open AccessArticle

A Custom Genetic Algorithm Framework for Early-Stage Optimization of Electromechanical Actuators

by Michelangelo Levati, Antonio Carlo Bertolino, Roberto Guida, Domenico Fabio Migliore, Edoardo Finamore and Massimo Sorli

Actuators 2026, 15(2), 99; https://doi.org/10.3390/act15020099 - 4 Feb 2026

Viewed by 726

Abstract

This work presents a systematic methodology for the preliminary design and optimization of electromechanical actuators, aimed at minimizing overall mass and rotational inertia while satisfying torque and speed requirements. The proposed approach integrates dimensionless scaling relationships, derived and corrected from catalog data, with [...] Read more.

This work presents a systematic methodology for the preliminary design and optimization of electromechanical actuators, aimed at minimizing overall mass and rotational inertia while satisfying torque and speed requirements. The proposed approach integrates dimensionless scaling relationships, derived and corrected from catalog data, with a genetic algorithm that performs multi-parameter optimization across different actuator architectures. The algorithm enables the exploration of non-linear and multi-modal design spaces, allowing the identification of balanced solutions between mechanical efficiency and dynamic performance, employing custom functions for individual generation, constraint handling, and compatibility verification to ensure feasible and consistent architecture designs throughout the optimization process. A case study on the steering system of an aircraft nose landing gear illustrates the method’s ability to define optimal design parameters in real mechanical systems. Linear and non-linear dynamic analyses confirmed the compliance of the optimized design with control and stability requirements. The study demonstrates how the developed custom constrained genetic optimization approach can effectively support the early design phase, reducing the computational effort required in further stages and improving the overall consistency of electromechanical actuator development. Full article

(This article belongs to the Special Issue Flight Control Systems and Dynamic Simulation for Aerospace Applications—2nd Edition)

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