Actuators

24 pages, 11163 KB

Open AccessArticle

Design and Implementation of a Quick-Change End-Effector Control System for Lightweight Robotic Arms in Workpiece Assembly Applications

by Guangxin Luan, Lingyan Hu and Raofen Wang

Actuators 2025, 14(12), 619; https://doi.org/10.3390/act14120619 - 18 Dec 2025

Viewed by 812

Abstract

This paper presents a lightweight end-effector quick-change control system for robotic arms, designed for scenarios such as workpiece assembly that require rapid switching between multiple end-effectors. The system utilizes a proprietary quick-change mechanism as its hardware foundation. Its main disk employs a modular [...] Read more.

This paper presents a lightweight end-effector quick-change control system for robotic arms, designed for scenarios such as workpiece assembly that require rapid switching between multiple end-effectors. The system utilizes a proprietary quick-change mechanism as its hardware foundation. Its main disk employs a modular and lightweight design compatible with small collaborative robots like the UR3. Motor-driven claws enable automatic tool locking and unlocking. To unify control interfaces for heterogeneous motor-driven tools, this paper proposes a universal peripheral adapter circuit based on the RS485 bus and a tool ID recognition mechanism, establishing a standardized four-wire interface for multi-tool sharing. At the control level, embedded control programs were developed for both the quick-change device and the tool end. An upper-level control platform based on ROS and MoveIt was established to achieve automatic quick-change and task sequence control during typical robotic operations such as “drilling-assembly workpiece.” Statistics from 20 locking time and communication success rate tests, along with 30 complete assembly experiments, demonstrate that the average quick-change locking time is 1.81 s, communication success rate is 100%, and a 93.3% assembly process success rate. These results validate the feasibility and stability of the proposed lightweight robotic arm end-effector quick-change control system in workpiece assembly scenarios, providing an expandable and reproducible quick-change control solution for multi-task operations of lightweight robotic arms. Full article

(This article belongs to the Section Actuators for Robotics)

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16 pages, 2902 KB

Open AccessArticle

Adaptive Backstepping Control for Battery Pole Strip Mill Systems with Friction and Dead-Zone Input Nonlinearities

by Gengting Qiu, Yujie Hao, Gexin Chen, Guishan Yan and Yao Chen

Actuators 2025, 14(12), 618; https://doi.org/10.3390/act14120618 - 17 Dec 2025

Viewed by 331

Abstract

The dead-zone input and hydraulic cylinder friction of the pump-controlled automatic gauge control (AGC) system introduce significant challenges to the high-precision rolling of lithium battery pole pieces. To address these nonlinearities, this paper establishes the friction and dead-zone model of the pump-controlled AGC [...] Read more.

The dead-zone input and hydraulic cylinder friction of the pump-controlled automatic gauge control (AGC) system introduce significant challenges to the high-precision rolling of lithium battery pole pieces. To address these nonlinearities, this paper establishes the friction and dead-zone model of the pump-controlled AGC system, and a slide-mode observer is designed to estimate the friction state z in the LuGre model. Furthermore, an adaptive compensation method is adopted to identify the unknown parameters of the input dead-zone and friction models. Meanwhile, combined with the framework of backstepping control design, both matched and mismatched disturbances are effectively compensated. Stability analysis guarantees the convergence of the estimation errors and closed-loop signal boundedness. Finally, experimental results validate the effectiveness and robustness of the proposed control strategy. Full article

(This article belongs to the Special Issue High-Performance Control of Electromechanical Servo System Based on Motor/Hydraulic Actuator)

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18 pages, 2222 KB

Open AccessArticle

Model-Free Multi-Parameter Optimization Control for Electro-Hydraulic Servo Actuators with Time Delay Compensation

by Haiwu Zheng, Hao Xiong, Dingxuan Zhao, Yinying Ren, Shuoshuo Cao, Ziqi Huang, Zeguang Hu, Zhuangding Zhou, Liqiang Zhao and Liangpeng Li

Actuators 2025, 14(12), 617; https://doi.org/10.3390/act14120617 - 17 Dec 2025

Cited by 3 | Viewed by 442

Abstract

System time delays and nonlinear unmodeled dynamics severely constrain the control performance of the Active Suspension Electro-Hydraulic Servo Actuator (ASEHSA). To tackle these challenges, this paper presents a Dynamic Error Differentiation-based Model-Free Adaptive Control (DE-MFAC) strategy integrated with an Improved Particle Swarm Optimization [...] Read more.

System time delays and nonlinear unmodeled dynamics severely constrain the control performance of the Active Suspension Electro-Hydraulic Servo Actuator (ASEHSA). To tackle these challenges, this paper presents a Dynamic Error Differentiation-based Model-Free Adaptive Control (DE-MFAC) strategy integrated with an Improved Particle Swarm Optimization (IPSO) algorithm. Established under the Model-Free Adaptive Control (MFAC) framework, the DE-MFAC integrates a dynamic error differentiation mechanism and an implicit expression of time delays, thus removing the dependence on a precise system model. The traditional PSO algorithm is improved by incorporating an inertia weight adjustment strategy and a boundary reflection wall strategy, which effectively mitigates the issues of local optima and boundary stagnation. In AMESim 2021, a 1/4 vehicle active suspension electro-hydraulic actuation system model is constructed. To ensure an impartial evaluation of controller performance, the IPSO algorithm is employed to optimize the parameters of the PID, MFAC, and DE-MFAC controllers, respectively. Co-simulations with Simulink 2023b are conducted under two time delay scenarios using a composite square-sine wave signal as the reference. The results indicate that all three IPSO-optimized controllers realize effective position tracking. Among them, the DE-MFAC controller exhibits the optimal performance, demonstrating remarkable advantages in reducing tracking errors and balancing settling time with overshoot. These findings verify the effectiveness of the proposed control strategy, time delay compensation mechanism, and optimization algorithm. Future research will involve validation on a physical ASEHSA platform, further exploration of the method’s applicability and robustness under diverse operating conditions, and extension to other industrial systems with similar nonlinear time delay features. Full article

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

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27 pages, 16212 KB

Open AccessArticle

Fault Tolerant Robust Control of Four-Wheel Independent Electro-Mechanical Brake Actuators Using Time Delay Control with Relative Weighting to Lateral Velocity and Yaw Rate

by Oh-Seok Kwon

Actuators 2025, 14(12), 616; https://doi.org/10.3390/act14120616 - 17 Dec 2025

Viewed by 325

Abstract

The electrification of vehicle chassis systems is increasingly important due to benefits such as vehicle lightweighting, enhanced safety, and design flexibility. However, faults in these systems can seriously compromise safety, making Fault Tolerant Control (FTC) essential. This study investigated FTC of four-wheel independent [...] Read more.

The electrification of vehicle chassis systems is increasingly important due to benefits such as vehicle lightweighting, enhanced safety, and design flexibility. However, faults in these systems can seriously compromise safety, making Fault Tolerant Control (FTC) essential. This study investigated FTC of four-wheel independent Electro-Mechanical Brake (EMB) actuators and proposed a method to prevent lane departure under actuator faults. Fault Tolerant Robust Control (FTRC) of four-wheel independent EMB actuators using Time Delay Control (TDC) was applied without Fault Detection and Diagnosis (FDD) to maintain real-time capability, and without steering control to reduce system complexity. In addition, for actuator faults causing large lateral displacements, a control strategy applying relative weighting to lateral velocity and yaw rate was introduced. The results showed that, even when the faults of the EMB actuators were severe and asymmetric between the left and right sides of the vehicle, overall vehicle stability—including lateral and yaw motions—was preserved through the proposed FTRC approach without FDD and steering control. Moreover, the relative weighting strategy effectively reduced lateral displacement, preventing lane departure. These findings highlight the significance of the proposed method for ensuring FTRC in electrified braking systems, enhancing safety, reducing lateral displacement, preventing lane departure, ensuring real-time capability, and reducing the complexity required in practical FTC. Full article

(This article belongs to the Special Issue Modeling and Control for Chassis Devices in Electric Vehicles—2nd Edition)

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28 pages, 5033 KB

Open AccessArticle

Simulation Method for Hydraulic Tensioning Systems in Tracked Vehicles Using Simulink–AMESim–RecurDyn

by Zian Ding, Shufa Sun, Hongxing Zhu, Zhiyong Yan and Yuan Zhou

Actuators 2025, 14(12), 615; https://doi.org/10.3390/act14120615 - 17 Dec 2025

Viewed by 832

Abstract

We developed a robust tri-platform co-simulation framework that integrates Simulink, AMESim, and RecurDyn to address the dynamic inconsistencies observed in traditional tensioning models for tracked vehicles. The proposed framework synchronizes nonlinear hydraulic dynamics, closed-loop control, and track–ground interactions within a unified time step, [...] Read more.

We developed a robust tri-platform co-simulation framework that integrates Simulink, AMESim, and RecurDyn to address the dynamic inconsistencies observed in traditional tensioning models for tracked vehicles. The proposed framework synchronizes nonlinear hydraulic dynamics, closed-loop control, and track–ground interactions within a unified time step, thereby ensuring causal consistency along the pressure–flow–force–displacement power chain. Five representative operating conditions—including steady tension tracking, random road excitation, steering/braking pulses, supply-pressure drops, and parameter perturbations—were analyzed. The results show that the tri-platform model reduces tracking error by up to 60%, shortens recovery time by 35%, and decreases energy consumption by 12–17% compared with dual-platform models. Both simulations and full-scale experiments confirm that strong cross-domain coupling enhances system stability, robustness, and energy consistency under variable supply pressure and parameter uncertainties. The framework provides a high-fidelity validation tool and a transferable modeling paradigm for electro-hydraulic actuation systems in tracked vehicles and other multi-domain machinery. Full article

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

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26 pages, 22711 KB

Open AccessFeature PaperArticle

Advanced Servo Control and Adaptive Path Planning for a Vision-Aided Omnidirectional Launch Platform in Sports-Training Applications

by Shuai Wang, Yinuo Xie, Kangyi Huang, Jun Lang, Qi Liu and Yaoming Zhuang

Actuators 2025, 14(12), 614; https://doi.org/10.3390/act14120614 - 15 Dec 2025

Viewed by 772

Abstract

A system-level scheme that couples a multi-dimensional attention-fused vision model and an improved Dijkstra planner is proposed for basketball robots in complex scenes. Fast-moving object detection, cluttered background recognition, and real-time path decision are targeted. For vision, the proposed YOLO11 with Multi-dimensional Attention [...] Read more.

A system-level scheme that couples a multi-dimensional attention-fused vision model and an improved Dijkstra planner is proposed for basketball robots in complex scenes. Fast-moving object detection, cluttered background recognition, and real-time path decision are targeted. For vision, the proposed YOLO11 with Multi-dimensional Attention Fusion (YOLO11-MAF) is equipped with four modules: Coordinate Attention (CoordAttention), Efficient Channel Attention (ECA), Multi-Scale Channel Attention (MSCA), and Large-Separable Kernel Attention (LSKA). Detection accuracy and robustness for high-speed basketballs are raised. For planning, an improved Dijkstra algorithm is proposed. Binary heap optimization and heuristic fusion cut time complexity from

O (V^{2})

to

O ((V + E) \log V)

. Redundant expansions are removed and planning speed is increased. A complete robot platform integrating mechanical, electronic, and software components is constructed. End-to-end experiments show the improved vision model raises mAP@0.5 by 0.7% while keeping real-time frames per second (FPS). The improved path planning algorithm cuts average compute time by 16% and achieves over 95% obstacle avoidance success. The work offers a new approach for real-time perception and autonomous navigation of intelligent sport robots. It lays a basis for future multi-sensor fusion and adaptive path planning research. Full article

(This article belongs to the Special Issue Advanced High-Precision Servo Control Systems in Industrial Applications)

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17 pages, 3579 KB

Open AccessArticle

Accuracy Evaluation of a Linear Servo Positioning System

by Tamás Tornai, János Simon, László Gogolák and Igor Fürstner

Actuators 2025, 14(12), 613; https://doi.org/10.3390/act14120613 - 15 Dec 2025

Viewed by 625

Abstract

Reliable positioning performance is crucial in precision industrial automation, especially under dynamic conditions. This research focuses on examining the accuracy of a toothed belt driven linear servo motor positioning system, with the aim of identifying the main factors influencing position deviation. The system [...] Read more.

Reliable positioning performance is crucial in precision industrial automation, especially under dynamic conditions. This research focuses on examining the accuracy of a toothed belt driven linear servo motor positioning system, with the aim of identifying the main factors influencing position deviation. The system was built on a Power Belt ITO 060M shaft, controlled by an Rtelligent RS200-G servo controller and an Omron CP1L-E PLC. Position measurement was performed by a laser distance meter and a Cognex IS2000C-130-40-SR8 industrial camera, both calibrated with certified gauge blocks. The linear unit was moved to predefined points at different speeds, accelerations, and decelerations profiles and the resulting position deviation was recorded for each case. Several analytical methods were used to evaluate the collected measurement data to determine which factors have the greatest impact on positioning error. The result showed that speed significantly affected the accuracy of the system, while the effects of deceleration and acceleration were less pronounced. The study contributes to the fine-tuning of linear motion system and the targeted improvement of their performance. Full article

(This article belongs to the Section Precision Actuators)

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11 pages, 2456 KB

Open AccessCommunication

A Three-Stage Amplification Mechanism for a Compact Piezoelectric Actuator

by Hsien-Shun Liao, Chi-Yun Wu and Chung-Hsu Lin

Actuators 2025, 14(12), 612; https://doi.org/10.3390/act14120612 - 15 Dec 2025

Viewed by 460

Abstract

Mechanical amplifiers can enhance the travel range of piezoelectric actuators, thereby expanding the applications of these actuators. Various amplification mechanisms have been proposed for piezoelectric actuators with different design requirements. For instance, rhombus- and bridge-type amplification mechanisms are compact and can therefore be [...] Read more.

Mechanical amplifiers can enhance the travel range of piezoelectric actuators, thereby expanding the applications of these actuators. Various amplification mechanisms have been proposed for piezoelectric actuators with different design requirements. For instance, rhombus- and bridge-type amplification mechanisms are compact and can therefore be applied in many applications with size restrictions. However, the amplification ratio of a single-stage rhombus- or bridge-type mechanism is limited. In this study, a novel three-stage amplifier was developed to achieve a high amplification ratio while keeping the device compact. A piezoelectric actuator integrated with this amplifier had a travel range of 207.5 μm, an amplification ratio of 13.7, and dimensions of 33.5 mm × 34.2 mm × 10 mm. Moreover, this actuator was used to construct a compact jetting dispenser with dimensions of 69 mm × 72 mm × 20 mm. Experimental results suggested that this dispenser can generate uniform and stable droplets, confirming the practical utility of the developed piezoelectric actuator. Full article

(This article belongs to the Section Actuator Materials)

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28 pages, 3859 KB

Open AccessArticle

Experimental Assessment of Semi-Active ECS Under Low-Friction Conditions with Integrated Roll–Yaw Control

by Jeongwoo Lee and Jaepoong Lee

Actuators 2025, 14(12), 611; https://doi.org/10.3390/act14120611 - 15 Dec 2025

Viewed by 392

Abstract

This study quantitatively evaluated the performance of a semi-active electronically controlled suspension (ECS) on low-friction (low-μ) road surfaces. A mid-size passenger vehicle equipped with a reverse-type continuously variable damper was tested through double lane change (DLC) maneuvers on the snow-covered Arjeplog test track [...] Read more.

This study quantitatively evaluated the performance of a semi-active electronically controlled suspension (ECS) on low-friction (low-μ) road surfaces. A mid-size passenger vehicle equipped with a reverse-type continuously variable damper was tested through double lane change (DLC) maneuvers on the snow-covered Arjeplog test track in Sweden. The proposed semi-active control logic, based on Skyhook control, was designed to enhance handling stability by integrating roll rate control with yaw moment compensation control using roll moment distribution. Under semi-active only operation, the peak yaw-rate amplitude decreased by approximately 16% compared with the conventional fixed-damping mode, confirming a clear improvement in yaw stability. Furthermore, when the ECS operated in conjunction with the vehicle dynamic control (VDC) system through a lateral-acceleration signal linkage, the vehicle exhibited smoother roll and yaw responses, as well as highly repeatable steering behavior, across multiple tests. These results demonstrate that the proposed semi-active ECS not only improves transient yaw stability but also enhances response consistency when combined with VDC, providing a practical foundation for integrated chassis control development under real-world low-µ conditions, such as snow and wet roads. Full article

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

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17 pages, 906 KB

Open AccessArticle

Observer-Based Adaptive Cruise Control with Input Saturation and Disturbance Attenuation: An LMI Approach

by Hayoon Jeon, Kwangil Lee and Han Sol Kim

Actuators 2025, 14(12), 610; https://doi.org/10.3390/act14120610 - 15 Dec 2025

Viewed by 372

Abstract

This paper addresses the observer-based controller design for adaptive cruise control (ACC) systems using a linear matrix inequality (LMI) framework, considering both input saturation and disturbance attenuation performance. To formulate the controller design problem as LMIs, the nonlinear input saturation is represented as [...] Read more.

This paper addresses the observer-based controller design for adaptive cruise control (ACC) systems using a linear matrix inequality (LMI) framework, considering both input saturation and disturbance attenuation performance. To formulate the controller design problem as LMIs, the nonlinear input saturation is represented as a convex combination of linear state feedback controllers. Unlike conventional approaches that only reformulate input saturation, this work further incorporates the estimated state and the decay rate of a Lyapunov function to establish an invariant level set condition, leading to a novel LMI-based design criterion. The proposed method incorporates level set conditions to handle input constraints and employs an

H_{\infty}

criterion to ensure disturbance attenuation. Since the resulting design conditions are non-convex due to bilinear matrix terms, a two-step approach is applied to derive the controller design conditions in the form of LMIs. Finally, simulation results are presented to demonstrate the effectiveness of the proposed method. Full article

(This article belongs to the Special Issue Advances in Dynamics and Motion Control of Unmanned Aerial/Underwater/Ground Vehicles—2nd Edition)

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12 pages, 3163 KB

Open AccessArticle

Cloud-Assisted Nonlinear Model Predictive Control with Deep Reinforcement Learning for Autonomous Vehicle Path Tracking

by Yuxuan Zhang, Bing Chen, Yan Wang and Nan Li

Actuators 2025, 14(12), 609; https://doi.org/10.3390/act14120609 - 13 Dec 2025

Viewed by 660

Abstract

Model Predictive Control (MPC) stands out as a prominent method for achieving optimal control in autonomous driving applications. However, the effectiveness of MPC approaches critically depends on the availability of accurate dynamic models and often necessitates substantial computational overhead for real-time optimization procedures [...] Read more.

Model Predictive Control (MPC) stands out as a prominent method for achieving optimal control in autonomous driving applications. However, the effectiveness of MPC approaches critically depends on the availability of accurate dynamic models and often necessitates substantial computational overhead for real-time optimization procedures at every iteration. Recently, the research community has been increasingly drawn to the concept of cloud-assisted MPC, which harnesses the capabilities of powerful cloud computing to provide users with on-demand computational resources and data storage services. Within these cloud-assisted MPC frameworks, control signals are merged with a cloud-based MPC, which leverages the substantial processing power of cloud infrastructure to determine optimal control actions using detailed nonlinear models for greater accuracy. Simultaneously, a local MPC runs on simplified linear models constrained by limited on-device computing resources, delivering prompt control responses at the cost of reduced model accuracy. To achieve an effective trade-off between rapid response and model fidelity, this work presents a new model-free deep reinforcement learning structure designed to merge cloud and local MPC outputs. Tests conducted on path-following scenarios show that the introduced method achieves superior control performance compared to existing reinforcement learning baselines and conventional rule-based fusion strategies. Full article

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

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23 pages, 7516 KB

Open AccessArticle

Ensuring Safe Physical HRI: Integrated MPC and ADRC for Interaction Control

by Gao Wang, Zhihai Lin, Feiyan Min, Deping Li and Ning Liu

Actuators 2025, 14(12), 608; https://doi.org/10.3390/act14120608 - 12 Dec 2025

Cited by 1 | Viewed by 449

Abstract

This paper proposes a safety-constrained interaction control scheme for robotic manipulators by integrating model predictive control (MPC) and active disturbance rejection control (ADRC). The proposed method is specifically designed for manipulators with complex nonlinear dynamics. To ensure that the control system satisfies safety [...] Read more.

This paper proposes a safety-constrained interaction control scheme for robotic manipulators by integrating model predictive control (MPC) and active disturbance rejection control (ADRC). The proposed method is specifically designed for manipulators with complex nonlinear dynamics. To ensure that the control system satisfies safety constraints during human–robot interaction, MPC is incorporated into the impedance control framework to construct a model predictive impedance controller (MPIC). By exploiting the prediction and constraint-handling capabilities of MPC, the controller provides guaranteed safety throughout the interaction process. Meanwhile, ADRC is employed to track the target joint control signals generated by the MPIC, where an extended state observer is utilized to compensate for dynamic modeling errors and nonlinear disturbances within the system, thereby achieving accurate trajectory tracking. The proposed method is validated through both simulation and real-world experiments, achieving high-performance interaction control with safety constraints at a 2 ms control cycle. The controller exhibits active compliant interaction behavior when the interaction stays within the constraint boundaries, while maintaining strict adherence to the safety constraints when the interaction tends to violate them. Full article

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

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20 pages, 7461 KB

Open AccessArticle

A Wall-Climbing Robot with a Mechanical Arm for Weld Inspection of Large Pressure Vessels

by Ming Zhong, Mingjian Pan, Zhengxiong Mao, Ruifei Lyu and Yaxin Liu

Actuators 2025, 14(12), 607; https://doi.org/10.3390/act14120607 - 12 Dec 2025

Viewed by 580

Abstract

Inspecting the inner walls of large pressure vessels requires accurate weld seam recognition, complete coverage, and precise path tracking, particularly in low-feature environments. This paper presents a fully autonomous mobile robotic system that integrates weld seam detection, localization, and tracking to support ultrasonic [...] Read more.

Inspecting the inner walls of large pressure vessels requires accurate weld seam recognition, complete coverage, and precise path tracking, particularly in low-feature environments. This paper presents a fully autonomous mobile robotic system that integrates weld seam detection, localization, and tracking to support ultrasonic testing. An improved Differentiable Binarization Network (DBNet) combined with the Spatially Variant Transformer (SVTR) model enhances digital stamp recognition, while weld paths are reconstructed from three-dimensional position data acquired via binocular stereo vision. To ensure complete traversal and accurate tracking, a global–local hierarchical planning strategy is implemented: the A-star (A*) algorithm performs global path planning, the Rapidly Exploring Random Tree Connect (RRT-Connect) algorithm handles local path generation, and point cloud normal–based spherical interpolation produces smooth tracking trajectories for robotic arm motion control. Experimental validation demonstrates a 94.7% digital stamp recognition rate, 95.8% localization success, 1.65 mm average weld tracking error, 2.12° normal fitting error, 98.2% seam coverage, and a tracking speed of 96 mm/s. These results confirm the system’s capability to automate weld seam inspection and provide a reliable foundation for subsequent ultrasonic testing in pressure vessel applications. Full article

(This article belongs to the Topic Advances in Mobile Robotics Navigation, 2nd Volume)

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18 pages, 2520 KB

Open AccessArticle

Dynamics Analysis of Multibody Systems Based on Flexible Thermal Coupling Solid Elements

by Zuqing Yu and Yibin Shen

Actuators 2025, 14(12), 606; https://doi.org/10.3390/act14120606 - 12 Dec 2025

Viewed by 371

Abstract

In high-precision fields such as automotive and aerospace, solid elements are commonly used to verify the dynamic response of key components, which can comprehensively simulate three-dimensional stress, deformation, and temperature field changes. In this study, a new thermo-dynamic coupled solid element is proposed, [...] Read more.

In high-precision fields such as automotive and aerospace, solid elements are commonly used to verify the dynamic response of key components, which can comprehensively simulate three-dimensional stress, deformation, and temperature field changes. In this study, a new thermo-dynamic coupled solid element is proposed, which is suitable for large deformations based on the absolute nodal coordinate formulation (ANCF). In ANCF, the position and gradient vectors, as generalized coordinates, are used to describe displacement fields. Similarly, the temperature and temperature gradient are used as generalized coordinates for describing the temperature field. The physical meaning of the temperature gradient is the change in temperature relative to the coordinates of matter. Therefore, the temperature field and displacement field can be described within the same isoparametric element. Based on the unified element grid to establish dynamic equations and heat transfer equations, it can describe the bidirectional coupling effect of two physical fields. The generalized-α method simultaneously solves the dynamic and heat transfer equations within one time step. For thermally induced vibrations of simply supported beams, the maximum absolute error of dimensionless displacement at test points is less than 0.001, and temperature error is less than 0.5 K. The remaining two examples demonstrate that the proposed method can be used for the dynamic response calculation of thermally coupled multibody systems. Full article

(This article belongs to the Section Control Systems)

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16 pages, 705 KB

Open AccessArticle

Event-Triggered Control for Discrete-Time Linear Systems Under Actuator and Sensor Constraints

by Jinze Jia, Yonggang Chen, Jishen Jia, Liping Luo and Rui Dong

Actuators 2025, 14(12), 605; https://doi.org/10.3390/act14120605 - 12 Dec 2025

Viewed by 487

Abstract

This paper focuses on designing an event-triggered dynamic output feedback controller for discrete-time linear systems subject to actuator and sensor constraints as well as external disturbances. A dynamic event-triggered condition with two generalized weighting parameters is introduced to regulate sensor-to-controller communication. By integrating [...] Read more.

This paper focuses on designing an event-triggered dynamic output feedback controller for discrete-time linear systems subject to actuator and sensor constraints as well as external disturbances. A dynamic event-triggered condition with two generalized weighting parameters is introduced to regulate sensor-to-controller communication. By integrating generalized sector conditions, Lyapunov analysis, and linearization techniques, sufficient conditions are derived in terms of linear matrix inequalities, ensuring bounded closed-loop trajectories, prescribed

H_{\infty}

performance, and asymptotic stability in the disturbance-free case. Furthermore, optimization problems are formulated to maximize the event-triggering rate while preserving the desired system performance. Simulation results show that, compared to time-triggered control, the event-triggered control effectively reduces the communication frequency, thereby significantly conserving communication resources. Compared with existing results, this work presents the first event-triggered dynamic output feedback scheme for discrete-time linear systems with dual saturation constraints. The inclusion of generalized weighting parameters and the use of generalized sector conditions allow the design to be carried out within a flexible local framework with reduced conservatism. Full article

(This article belongs to the Section Control Systems)

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27 pages, 1372 KB

Open AccessArticle

Discovering Control Scheduler Policies Through Reinforcement Learning and Evolutionary Strategies

by Aureo Guilherme Dobrikopf, Gabriel Abatti and Douglas Wildgrube Bertol

Actuators 2025, 14(12), 604; https://doi.org/10.3390/act14120604 - 12 Dec 2025

Viewed by 536

Abstract

This work investigates the viability of using NNs to select an appropriate controller for a dynamic system based on its current state. To this end, this work proposes a method for training a controller-scheduling policy using several learning algorithms, including deep reinforcement learning [...] Read more.

This work investigates the viability of using NNs to select an appropriate controller for a dynamic system based on its current state. To this end, this work proposes a method for training a controller-scheduling policy using several learning algorithms, including deep reinforcement learning and evolutionary strategies. The performance of these scheduler-based approaches is evaluated on an inverted pendulum, and the results are compared with those of NNs that operate directly in a continuous action space and a backpropagation-based Control Scheduling Neural Network. The results demonstrate that machine learning can successfully train a policy to choose the correct controller. The findings highlight that evolutionary strategies offer a compelling trade-off between final performance and computational time, making them an efficient alternative among the scheduling methods tested. Full article

(This article belongs to the Special Issue Neural Networks-Based Modeling and Control for Uncertain Dynamical Systems)

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21 pages, 3658 KB

Open AccessArticle

Fault Tolerant Control of Integrated Autonomous Wheel Module Vehicle Subject to Independent Steering Actuator Degradation

by Liqiang Jin, Bohao Jin, Yan Huang, Qixiang Zhang, Haixia Yi and Ronghua Li

Actuators 2025, 14(12), 603; https://doi.org/10.3390/act14120603 - 10 Dec 2025

Viewed by 742

Abstract

This study investigates the issue of fault-tolerant motion control in the distributed chassis system (DCS) subject to degradation in independent steering actuators. First, the dynamic behavior of the independent steering system is analyzed to establish a fault-dynamics model for independent steering. The steering [...] Read more.

This study investigates the issue of fault-tolerant motion control in the distributed chassis system (DCS) subject to degradation in independent steering actuators. First, the dynamic behavior of the independent steering system is analyzed to establish a fault-dynamics model for independent steering. The steering powertrain degradation coefficient is then mapped to the contraction of the feasible tire-force region. Subsequently, the model predictive controller (MPC) is designed to solve for the required generalized forces/torques. Moreover, along the direction of the generalized demand force vector, the boundary values for the current cycle are obtained and used to correct the generalized demand force. Finally, an adaptive weighting scheme for the tire force distribution objective function, which accounts for degradation coefficients, is proposed. Sequential quadratic programming (SQP) is employed to achieve optimal utilization of tire forces. Simulation studies for different steering degradation scenarios and road conditions are conducted using a CarSim 2019 and Simulink 2021B co-simulation platform. The simulation results demonstrate that the proposed integrated chassis motion controller maintains excellent motion control performance even under independent steering actuator degradation. 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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18 pages, 4234 KB

Open AccessArticle

A Four-Chamber Multimodal Soft Actuator and Its Application

by Jiabin Yang, Helei Zhu, Gang Chen, Jianbo Cao, Jiwei Yuan and Kaiwei Wu

Actuators 2025, 14(12), 602; https://doi.org/10.3390/act14120602 - 9 Dec 2025

Viewed by 524

Abstract

Soft robotics represents a rapidly advancing and significant subfield within modern robotics. However, existing soft actuators often face challenges including unwanted deformation modes, limited functional diversity, and a lack of versatility. This paper presents a four-chamber multimodal soft actuator with a centrally symmetric [...] Read more.

Soft robotics represents a rapidly advancing and significant subfield within modern robotics. However, existing soft actuators often face challenges including unwanted deformation modes, limited functional diversity, and a lack of versatility. This paper presents a four-chamber multimodal soft actuator with a centrally symmetric layout and independent pneumatic control. While building on existing multi-chamber concepts, the design incorporates a cruciform constraint layer and inter-chamber gaps to improve directional bending and reduce passive chamber deformation. An empirical model based on the vector superposition of single- and dual-chamber inflations is developed to describe the bending behavior. Experimental results show that the actuator can achieve omnidirectional bending with errors below 5% compared to model predictions. To demonstrate versatility, the actuator is implemented in two distinct applications: a three-finger soft gripper that can grasp objects of various shapes and perform in-hand twisting maneuvers, and a steerable crawling robot that mimics inchworm locomotion. These results highlight the actuator’s potential as a reusable and adaptable driving unit for diverse soft robotic tasks. Full article

(This article belongs to the Section Actuators for Robotics)

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26 pages, 7133 KB

Open AccessArticle

HASEL Actuators Activated with a Multi-Channel Low-Cost High Voltage Power Supply

by Levi Tynan, Upul Gunawardana, Daniele Esposito, Jessica Centracchio, Simone Minucci, Andrea Gaetano Chiariello and Gaetano Gargiulo

Actuators 2025, 14(12), 601; https://doi.org/10.3390/act14120601 - 8 Dec 2025

Viewed by 727

Abstract

Hydraulically Amplified Self-Healing Electrostatic (HASEL) actuators promise a future of adaptive robotics in a world where robotics is becoming increasingly integrated into our daily lives. Adaptive robotics needs to control multiple outputs with precision and speed. Unfortunately, expensive High Voltage control restricts the [...] Read more.

Hydraulically Amplified Self-Healing Electrostatic (HASEL) actuators promise a future of adaptive robotics in a world where robotics is becoming increasingly integrated into our daily lives. Adaptive robotics needs to control multiple outputs with precision and speed. Unfortunately, expensive High Voltage control restricts the development of the HASEL actuator for commercial applications. This paper demonstrates a low-cost multi-channel High Voltage Power Supply (HVPS). The HVPS takes a 6 V input and controls multiple HASEL actuators from 0 to 10 kV, with a slew rate of up to 117.7 kV/s. In addition to controlling multiple channels, the low-cost HVPS can control two outputs with a single control module in an alternating pattern, similar to the way muscles control movement in alternating sequences—e.g., biceps and triceps. Previous work has shown that this low-cost HVPS is 95% cheaper than other power supplies used in the field of HASEL actuators. This work builds on the work reducing the cost of the HVPS by an additional 40%. This low-cost HVPS also reduces the amount of input required for control from four PWMs to one PWM with enable pins, drastically improving the performance of the device for multi-channel operation. Full article

(This article belongs to the Special Issue Multifunctional Actuators: Design, Control and Integration)

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20 pages, 4884 KB

Open AccessArticle

Research on a Passive-Tuned Magnetorheological Damper for Whole-Spacecraft Vibration Isolation

by Lifan Wu, Xiaomin Dong, Kaixiang Wang, Jialong Wang, Xiangcheng Fang and Huan Zhou

Actuators 2025, 14(12), 600; https://doi.org/10.3390/act14120600 - 8 Dec 2025

Viewed by 508

Abstract

During the launch phase of a carrier rocket, the spacecraft carried by the rocket will be subjected to strong vibrations from the rocket body. Therefore, based on the special working conditions during the rocket launch phase, a passive-tuned magnetorheological (PT-MR) damper using the [...] Read more.

During the launch phase of a carrier rocket, the spacecraft carried by the rocket will be subjected to strong vibrations from the rocket body. Therefore, based on the special working conditions during the rocket launch phase, a passive-tuned magnetorheological (PT-MR) damper using the magnetorheological (MR) composite was proposed, which achieves stable and efficient operational performance using permanent magnets (PMs). Firstly, the influence of squeeze mode on the performances of the MR composite was analyzed for different vibration conditions. Then, by analyzing the squeeze strengthening effect of the MR composite and the influence of non-uniform radial gap size on the damping force, the mechanical model of the proposed damper was derived. Furthermore, the damper prototype was fabricated and its mechanical properties were tested, and the test results showed that the proposed damper can generate a damping force exceeding 800 N. Finally, the vibration isolation effectiveness of the proposed damper was verified from a system perspective by building the simulation model of whole-spacecraft vibration isolation. Full article

(This article belongs to the Special Issue Advances in Electrorheological and Magnetorheological Materials: Material Design, Control and Industrial Applications)

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25 pages, 17821 KB

Open AccessArticle

Study on Hydrodynamic Characteristics of a New Type of Cartridge-Type Locking Valve

by Guangchao Zhang, Yudong Xie, Yi Wan, Chuanying Wang, Fujian Chen, Xiangqian Zhu, Shuai Ji, Dong Wang, Xiao Han, Zhisheng Li, Zilei Ji, Shawuti Yingming and Geyu Zhu

Actuators 2025, 14(12), 599; https://doi.org/10.3390/act14120599 - 7 Dec 2025

Viewed by 349

Abstract

As a core safety component in the hydraulic system of CNC stretching pads, the safety locking valve undertakes precise stamping position maintenance and emergency braking protection; its performance dictates the hydraulic system’s operational stability. Existing ones induce hydraulic oil volume dynamic changes during [...] Read more.

As a core safety component in the hydraulic system of CNC stretching pads, the safety locking valve undertakes precise stamping position maintenance and emergency braking protection; its performance dictates the hydraulic system’s operational stability. Existing ones induce hydraulic oil volume dynamic changes during opening/closing, significantly affecting blank holder force control. To solve this, its structure is innovatively optimized. Based on the CFD method, a dynamic calculation framework integrating unsteady flow characteristics and structural motion characteristics has been constructed, realizing accurate simulation research on the dynamic characteristics of the safety locking valve. Through simulation analysis, the distribution law of the internal flow field during the transient opening and closing process of the locking valve has been thoroughly explored, the distribution mechanism of the transient flow field has been systematically revealed, and finally, the fluid regulation characteristic parameters of the safety locking valve have been obtained, providing an important theoretical basis for subsequent engineering applications. Full article

(This article belongs to the Special Issue Flow Control and Beyond Enhancing Performance and Energy Efficiency in Complex Fluid System)

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16 pages, 2857 KB

Open AccessArticle

Validation of Pneumatic Actuation for Fast Fatigue Testing of Additive-Manufactured Polymers

by Davide D’Andrea, Giacomo Risitano and Dario Santonocito

Actuators 2025, 14(12), 598; https://doi.org/10.3390/act14120598 - 7 Dec 2025

Viewed by 1832

Abstract

In the modern industrial context, many manufacturers design universal testing machines (UTMs) equipped with servo-hydraulic or electromechanical linear actuators, which offer excellent control capabilities and high-quality force signal measurement, at the expense of high costs due to the need for hydraulic power units [...] Read more.

In the modern industrial context, many manufacturers design universal testing machines (UTMs) equipped with servo-hydraulic or electromechanical linear actuators, which offer excellent control capabilities and high-quality force signal measurement, at the expense of high costs due to the need for hydraulic power units or dedicated electrical networks. The complexity of these systems discourages manufacturers of mechanical components, especially the ones produced through additive manufacturing (AM), from investing in machines for the determination of mechanical properties according to international standards, settling instead for information derived from technical datasheets of the base material (filament or powders), which rarely include information about fatigue life. Within this context, the Fast Fatigue Machine (FFM), designed by KnoWow srl and ItalSigma srl, makes mechanical characterization of materials a process accessible to any organization that may require it. This was made possible by designing a pneumatic benchtop testing machine with a built-in setup for Thermographic Methods (TMs) usage. The aim of this work is to validate pneumatic actuators as a viable alternative to servo-hydraulic systems, demonstrating their effectiveness and reliability. Frequency analysis on both sinusoidal waveforms, root mean square error (RMSE) evaluation, and percentage total harmonic distortion (THD%) calculations showed that, while the servo-hydraulic system closely follows the load signal with a THD of around 5%, regardless of the applied load intensity, the pneumatic system exhibits higher distortion (THD of approximately 9%, strongly dependent on the load levels) and a high-frequency harmonic component, which, however, does not affect the overall results. Life cycle assessment (LCA) analysis confirmed the convenience of the pneumatic system and TMs in material testing and fatigue characterization. Full article

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

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25 pages, 3707 KB

Open AccessArticle

Coordinated Control for Stability of Four-Wheel Steering Vehicles Based on Game Theory

by Gang Liu

Actuators 2025, 14(12), 597; https://doi.org/10.3390/act14120597 - 7 Dec 2025

Viewed by 494

Abstract

To address the poor stability of four-wheel steering vehicles under extreme conditions, this paper proposes a coordinated control strategy for vehicles with four-wheel independent drive. The strategy combines the Active Four-Wheel Steering system with the Direct Yaw Moment Control system. First, a shared [...] Read more.

To address the poor stability of four-wheel steering vehicles under extreme conditions, this paper proposes a coordinated control strategy for vehicles with four-wheel independent drive. The strategy combines the Active Four-Wheel Steering system with the Direct Yaw Moment Control system. First, a shared steering control model is constructed by considering both the vehicle’s path-tracking performance and handling stability. Based on this model, a control strategy for the four-wheel steering system is proposed using a non-cooperative Nash game. Next, a direct yaw moment controller is designed to improve vehicle lateral stability under dangerous driving conditions. To achieve synergy between rear-wheel steering and direct yaw moment control, a rule-based coordination strategy is introduced to optimize the working intervals of each sub-controller. Finally, experimental verification is performed under double-lane-change and slalom conditions using the CarSim/Simulink hardware-in-the-loop platform. All computations were done in MATLAB R2024a, using specific m-files and Simulink functions for implementation, and the controller was implemented using the Micro-Autobox tool. The results demonstrate that the proposed control strategy significantly enhances vehicle path-tracking accuracy and handling stability under extreme driving conditions. Full article

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

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24 pages, 6391 KB

Open AccessReview

Machine Learning for Fault Diagnosis of Electric Motors in Actuator Systems

by Wenjie Liu, Zhexiang Zou, Fengshou Gu and Guoji Shen

Actuators 2025, 14(12), 596; https://doi.org/10.3390/act14120596 - 6 Dec 2025

Cited by 1 | Viewed by 1323

Abstract

Electric linear or rotary actuators are the ultimate power-dense execution units in modern industrial and transportation systems, yet their dependability is directly governed by the health of the driving electric motor. To guarantee fail-safe operation of the electromechanical actuator chain, condition monitoring and [...] Read more.

Electric linear or rotary actuators are the ultimate power-dense execution units in modern industrial and transportation systems, yet their dependability is directly governed by the health of the driving electric motor. To guarantee fail-safe operation of the electromechanical actuator chain, condition monitoring and fault diagnosis of the embedded motor have become indispensable. The motor fault diagnosis process can be comprehensively summarized into four key steps: signal acquisition, feature extraction, condition monitoring, and fault identification. Based on the data obtained by signal acquisition, machine learning methods can be effectively integrated into the latter three steps. Feature extraction techniques primarily revolve around autoencoders. In terms of condition monitoring technology, in-depth research has been conducted on image recognition, including the identification of two-dimensional and three-dimensional images. In terms of fault identification, various machine learning methods have been applied, such as convolutional neural networks, autoencoders, transfer learning, long short-term memory networks, and support vector machines. Finally, the potential application of the Large Language Model in motor fault diagnosis was explored. Full article

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

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16 pages, 2849 KB

Open AccessArticle

On the Iron Loss Reduction Design Improvement of an Axial Flux Permanent Magnet Motor

by Seung-Mi Oh, Kan Akatsu, Dong-Woo Lee and Ho-Joon Lee

Actuators 2025, 14(12), 595; https://doi.org/10.3390/act14120595 - 5 Dec 2025

Viewed by 757

Abstract

Reducing iron loss in axial flux permanent magnet (AFPM) motors is critical for improving efficiency. This study proposes a design-optimization procedure that combines 3D finite-element analysis (FEA) data with an artificial neural network (ANN) surrogate. For four design variables—airgap length, rotor back-yoke thickness, [...] Read more.

Reducing iron loss in axial flux permanent magnet (AFPM) motors is critical for improving efficiency. This study proposes a design-optimization procedure that combines 3D finite-element analysis (FEA) data with an artificial neural network (ANN) surrogate. For four design variables—airgap length, rotor back-yoke thickness, stator slot width, and stator slot depth—the search bounds were defined to avoid tooth and back-yoke saturation, and the corresponding space was sampled to construct a dataset. Using this dataset, the ANN was trained and then used to explore low-iron loss solutions. On an independent validation set, ANN predictions showed high agreement with 3D-FEA reference values, enabling rapid evaluation of many design candidates. As a result of the optimization, total iron loss decreased relative to the baseline, and torque increased by 3 Nm. These results demonstrate that the ANN-based surrogate model can reliably perform geometry-dependent iron loss optimization in AFPM motors, providing a fast and accurate alternative to repetitive 3D-FEA evaluations. Full article

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

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31 pages, 19249 KB

Open AccessArticle

Research on the Dynamic Behavior of Rotor–Stator Systems Considering Bearing Clearance in Aeroengines

by Yongbo Ma, Zhihong Song, Zhefu Yang, Chao Li, Yanhong Ma and Jie Hong

Actuators 2025, 14(12), 594; https://doi.org/10.3390/act14120594 - 4 Dec 2025

Cited by 1 | Viewed by 516

Abstract

The high-performance aeroengine operates under extreme loads. In engineering practice, the vibration problems caused by stator vibrations have become increasingly prominent, with impacts on the rotor dynamic behavior. This paper takes the rotor–stator system of aeroengines as the analysis object and studies the [...] Read more.

The high-performance aeroengine operates under extreme loads. In engineering practice, the vibration problems caused by stator vibrations have become increasingly prominent, with impacts on the rotor dynamic behavior. This paper takes the rotor–stator system of aeroengines as the analysis object and studies the influence of stator modal vibration on the rotor dynamic behavior. The dynamic model of the rotor–stator system has been established, and the influence of the contact state of cylindrical roller bearings (CRBs) has been analyzed by considering bearing clearance. To precisely capture the transient contact state within the CRBs, a numerical method combining the Newmark-β method with the Event Function has been developed. The numerical calculation results show that the collision effect introduced by the bearing clearance will excite a localized stator mode at the supercritical state, which fundamentally alters the rotor dynamic behavior: generating prominent combination frequencies

f_{M} \pm f_{r}

due to modulation between the rotor rotation

f_{r}

and the stator vibration

f_{M}

. Moreover, good consistency between the experimental and calculated results has been obtained. This study demonstrates that the stator modal vibration can critically modify rotor dynamic behavior in supercritical operation, leading to potentially hazardous non-synchronous whirl. The integrated model and numerical method provide a robust framework for analyzing complex rotor–stator interactions, offering significant insights for vibration control and fault diagnosis in high-speed rotating machinery. Full article

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

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16 pages, 4893 KB

Open AccessArticle

Precision Pressure Pump Featuring Dual-Valve Control and Onboard Compression for Microfluidic Systems

by Mohammad Zein, Ruddy Moussahou, Sousso Kelouwani and Marie Hébert

Actuators 2025, 14(12), 593; https://doi.org/10.3390/act14120593 - 4 Dec 2025

Cited by 1 | Viewed by 658

Abstract

The essence of microfluidics lies in its ability to manipulate fluids within compact and portable systems. However, existing pressure pumps rely on bulky external compressors and are costly. Open-source solutions are generally suited for passive microfluidic applications due to their slow settling times [...] Read more.

The essence of microfluidics lies in its ability to manipulate fluids within compact and portable systems. However, existing pressure pumps rely on bulky external compressors and are costly. Open-source solutions are generally suited for passive microfluidic applications due to their slow settling times (1500–2500 s). The innovative pressure regulator developed uses two proportional solenoid valves and a built-in compression unit. The pressure regulation is ensured by a Proportional–Integral–Derivative (PID) controller. A comparative analysis is conducted between the developed regulator and a commercial regulator (Marsh Bellofram). Both regulators provide a comparable accuracy of about ±0.01 psi (±0.7 mbar) from the desired pressure. However, our regulator demonstrates a faster settling time (∼100 ms vs. ∼200 ms), which is particularly desirable for implementation in an active system, while offering a lower price (∼USD 250 vs. ∼USD 1000). We present a cost-effective, compact pressure pump that does not rely on bulky compressors. It delivers fast and precise pressure, even at low pressure, making it suitable for both active and passive microfluidic applications. This design improves access to pressure regulation in microfluidics for low-budget laboratories and limited infrastructure environments. Full article

(This article belongs to the Special Issue Design, Hydrodynamics, and Control of Valve Systems)

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19 pages, 10396 KB

Open AccessArticle

A Fan-Array Robotic-Arm Approach to Characterization of Pitch-Rate Dynamics of a Flapping-Wing MAV

by Woei-Leong Chan, De-Jing Liu, Hung-Yu Chen and Chia-Le Chin

Actuators 2025, 14(12), 592; https://doi.org/10.3390/act14120592 - 4 Dec 2025

Cited by 1 | Viewed by 531

Abstract

Flapping-wing micro-air vehicles (FWMAVs) exhibit unique aerodynamic characteristics that differ fundamentally from other aircraft, yet little is known about their dynamic stability derivatives. This study aims to identify pitch-rate stability derivatives of an in-house prototype, CKopter-1, to advance the modeling and control of [...] Read more.

Flapping-wing micro-air vehicles (FWMAVs) exhibit unique aerodynamic characteristics that differ fundamentally from other aircraft, yet little is known about their dynamic stability derivatives. This study aims to identify pitch-rate stability derivatives of an in-house prototype, CKopter-1, to advance the modeling and control of bio-inspired flight. Experiments were conducted using a robotic-arm fan-array system that enabled prescribed pitching motions under controlled inflow. Aerodynamic forces and moments were measured with a six-axis load cell, while vehicle kinematics were captured using motion tracking and synchronized during post-processing. Tests consisted of quasi-static cycles and dynamic cycles at pitch rates of 35°/s, 58.8°/s, and 68.4°/s. The results revealed static instability below an angle of attack of 33°, a trim condition near 58.5°, and positive stability up to 72.5°. Dynamic cases showed clear pitch-rate effects in the longitudinal components, from which the derivatives were extracted. A comparison with previous studies confirmed comparable magnitudes, with systematic differences attributable to wing dihedral and tail length. This study demonstrates that the fan-array robotic-arm method enables stability derivative identification even beyond feasible flight regimes, providing valuable parameters for future flight dynamics modeling and control of FWMAVs. Full article

(This article belongs to the Special Issue Analysis and Design of Linear/Nonlinear Control System—2nd Edition)

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14 pages, 3238 KB

Open AccessArticle

An Adaptive Preload Device for High-Speed Motorized Spindles for Teaching and Scientific Research

by Haipeng Yan, Zongchu Zhang, Guisen Wang, Jinda Zhu and Tingting Sun

Actuators 2025, 14(12), 591; https://doi.org/10.3390/act14120591 - 3 Dec 2025

Viewed by 429

Abstract

This study focuses on an experimental device for the adaptive adjustment of the preload of high-speed motorized spindles. Firstly, based on Hirano’s criterion, the optimal preload for bearings at different rotational speeds was determined, and an adaptive preload adjustment mechanism was developed, with [...] Read more.

This study focuses on an experimental device for the adaptive adjustment of the preload of high-speed motorized spindles. Firstly, based on Hirano’s criterion, the optimal preload for bearings at different rotational speeds was determined, and an adaptive preload adjustment mechanism was developed, with its accuracy experimentally validated. Secondly, the optimal lubrication conditions were obtained by a single-factor experiment. Then, the vibration characteristics under different preload conditions were explored, and the axial displacement variations were analyzed across a range of rotational speeds. Finally, the temperature rise in the bearings with the speed at the constant preload force and the optimal preload force were compared. The results demonstrated that the adaptive preload adjustment device outperformed the constant preload application. In teaching practice, this study enhanced students’ systematic understanding of the adaptive preload adjustment process in motorized spindles, promoted the integration of theoretical knowledge with practical application, and strengthened their learning interest. In addition, this device can provide experimental equipment for studying the performance of high-speed motorized spindles and bearings in scientific research. Full article

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

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17 pages, 4374 KB

Open AccessArticle

Nonlinear Controller for Keeping Pulsed-Power Resonant Inverter Driving Time-Varying Series RLC Load in Resonance

by Ohad Akler, Natan Schecter and Alon Kuperman

Actuators 2025, 14(12), 590; https://doi.org/10.3390/act14120590 - 3 Dec 2025

Viewed by 654

Abstract

Capacitor-powered resonant inverters are often employed in pulsed-power applications to feed an equivalent series resistance–inductance–capacitance (RLC) load with time-varying component values. Establishing the short-time dynamics of such an arrangement is nontrivial since the system does not reach a steady state within a single [...] Read more.

Capacitor-powered resonant inverters are often employed in pulsed-power applications to feed an equivalent series resistance–inductance–capacitance (RLC) load with time-varying component values. Establishing the short-time dynamics of such an arrangement is nontrivial since the system does not reach a steady state within a single pulse period. As a result, linearization around a single operation point cannot be applied for the sake of simplified system modeling. Consequently, the design of feedback controllers for such systems (aiming for, e.g., resonant frequency tracking or energy transfer rate regulation) is highly cumbersome and challenging since a linear time-invariant regulator is unable to bring the system to desired performance within the whole expected operation range. To cope with the modeling task, a reduced-order envelope model of a capacitor-fed resonant inverter feeding a time-varying RLC load was recently proposed by the authors. In this paper, this model is further simplified and split into linear and nonlinear parts, allowing the employment of a combination of feedback linearizing (nonlinear) action with a linear time-invariant regulator to form a nonlinear control structure allowing the attainment of resonant frequency tracking within a wide operation range. The proposed controller design methodology is accurately validated by multiple time-domain simulations. Full article

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

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Actuators, Volume 14, Issue 12 (December 2025) – 54 articles

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