Actuators

15 pages, 36452 KiB

Open AccessArticle

Adaptive NN Force Loading Control of Electro-Hydraulic Load Simulator

by Zanwei Chen, Hao Yan, Peng Zhang, Jiefeng Shan and Jiafeng Li

Actuators 2024, 13(12), 471; https://doi.org/10.3390/act13120471 - 22 Nov 2024

To address the issues of derivative explosion in traditional backstepping control and the strong nonlinearity of hydraulic systems, this paper develops an adaptive neural network control method tailored for electro-hydraulic load simulators. Neural networks are employed to handle external disturbances, modeling uncertainties, and [...] Read more.

To address the issues of derivative explosion in traditional backstepping control and the strong nonlinearity of hydraulic systems, this paper develops an adaptive neural network control method tailored for electro-hydraulic load simulators. Neural networks are employed to handle external disturbances, modeling uncertainties, and the derivatives of virtual control inputs. First, the precise state-space equations of the system are derived. Next, the approximation property of neural networks is used to design an adaptive backstepping controller, and the symmetric barrier Lyapunov function is used to prove the boundedness of the controller and control parameters. Finally, experiments are conducted to verify the effectiveness and reliability of the control algorithm. The results demonstrate that the proposed control algorithm exhibits excellent tracking performance and effectively reduces control errors. Full article

(This article belongs to the Section Control Systems)

16 pages, 1955 KiB

Open AccessArticle

Adaptive Recognition and Control of Shield Tunneling Machine in Soil Layers Containing Plastic Drainage Boards

by Qiuping Wang, Wanli Li, Zhikuan Xu and Yougang Sun

Actuators 2024, 13(12), 470; https://doi.org/10.3390/act13120470 - 22 Nov 2024

Abstract

The underground plastic vertical drains (PVDs) are a significant problem for shield machines in tunneling construction. At present, the main method to deal with PVDs is to manually adjust the parameters of the shield machine. To ensure that a shield machine autonomously recognizes [...] Read more.

The underground plastic vertical drains (PVDs) are a significant problem for shield machines in tunneling construction. At present, the main method to deal with PVDs is to manually adjust the parameters of the shield machine. To ensure that a shield machine autonomously recognizes and adjusts the control in soil layers containing PVDs, this study constructs a shield machine advance and rotation state-space model utilizing Bayesian decision theory for the judgment of excavation conditions. A Bayesian model predictive control (Bayes-MPC) method for the shield machine is proposed, followed by a simulation analysis. Finally, a validation experiment is conducted based on a Singapore subway project. Compared with traditional methods, the method proposed in this paper has better performance in the simulation, and it also has demonstrated effectiveness and accuracy in experiments. The research outcomes can provide a reference for the adaptive assistance system of shield machines excavating underground obstacles. Full article

(This article belongs to the Section Actuators for Land Transport)

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14 pages, 2335 KiB

Open AccessArticle

Multi-Objective Parameter Optimization of Rotary Screen Coating Process for Structural Plates in Spacecraft

by Yanhui Guo, Yanpeng Chen, Peibo Li, Xinfu Chi and Yize Sun

Actuators 2024, 13(12), 469; https://doi.org/10.3390/act13120469 - 22 Nov 2024

Abstract

A multi-objective grasshopper optimization algorithm (MOGOA) with an adaptive curve c(t) and the enhanced Levy fight strategy (CLMOGOA) was proposed to optimize the process parameters of rotary screen coating, setting the thickness and uniformity of the adhesive layer on the structural plates in [...] Read more.

A multi-objective grasshopper optimization algorithm (MOGOA) with an adaptive curve c(t) and the enhanced Levy fight strategy (CLMOGOA) was proposed to optimize the process parameters of rotary screen coating, setting the thickness and uniformity of the adhesive layer on the structural plates in spacecraft as its optimization objectives. The adaptive curve strikes a balance between global exploration and local development and accelerates the convergence speed. The enhanced Levy strategy helps the algorithm to escape local optimizations, increases the population diversity, and possesses dual searching capabilities. After multiple runs, the average values of the CLMOGOA’s reverse generation distance were 0.0288, 0.0233, and 0.1810 on the test sets, which were less than those of the MOGOA. The best Pareto-optimal front obtained by the CLMOGOA had a higher accuracy and better coverage compared to that of the MOGOA. Thus, it is indicated that the CLMOGOA managed to outperform the MOGOA on the test functions. In order to solve the optimization problem, 108 sets of process experiments were designed, and then the experimental data were used to train a Back Propagation Neural Network (BPNN), a Least Squares Support Vector Machine (LSSVM), and Random Forest (RF) to obtain the best prediction model for the process parameters. Considering the thickness and uniformity of the adhesive layer as the objectives, the improved algorithm was used to optimize the prediction model to obtain the optimal process parameters. The actual coating effect showed that the optimization algorithm improved the efficiency and qualification rate of the product. Full article

(This article belongs to the Section Aircraft Actuators)

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15 pages, 7374 KiB

Open AccessArticle

Hysteresis Compensation and Butterworth Pattern-Based Positive Acceleration Velocity Position Feedback Damping Control of a Tip-Tilt-Piston Piezoelectric Stage

by Helei Zhu, Jinfu Sima, Peixing Li, Leijie Lai and Zhenfeng Zhou

Actuators 2024, 13(12), 468; https://doi.org/10.3390/act13120468 - 21 Nov 2024

Abstract

In order to solve the hysteresis nonlinearity and resonance problems of piezoelectric stages, this paper takes a three-degree-of-freedom tip-tilt-piston piezoelectric stage as the object, compensates for the hysteresis nonlinearity through inverse hysteresis model feedforward control, and then combines the composite control method of [...] Read more.

In order to solve the hysteresis nonlinearity and resonance problems of piezoelectric stages, this paper takes a three-degree-of-freedom tip-tilt-piston piezoelectric stage as the object, compensates for the hysteresis nonlinearity through inverse hysteresis model feedforward control, and then combines the composite control method of positive acceleration velocity position feedback damping control and high-gain integral feedback controller to suppress the resonance of the system and improve the tracking speed and positioning accuracy. Firstly, the three-degree-of-freedom motion of the end-pose is converted into the output of three sets of piezoelectric actuators and single-axis control is performed. Then, the rate-dependent Prandtl–Ishlinskii model is established and the parameters of the inverse model are identified. The accuracy and effectiveness of parameter identification are verified through open-loop and closed-loop compensation experiments. After that, for the third-order system, the parameters of positive acceleration velocity position feedback damping control and high-gain integral feedback controller are designed as a whole based on the pattern of the Butterworth filter. The effectiveness of the design method is proved by step signal and triangle wave signal trajectory tracking experiments, which suppresses the resonance of the system and improves the bandwidth of the system and the tracking speed of the stage. Full article

(This article belongs to the Section Control Systems)

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26 pages, 10651 KiB

Open AccessArticle

Research on Speed Control Strategies for Explosion-Proof Diesel Engine Monorail Cranes

by Hai Jiang, Dongjie Wang, Jiameng Cheng, Penghui Li, Xiaodong Ji, Yang Shen and Miao Wu

Actuators 2024, 13(12), 467; https://doi.org/10.3390/act13120467 - 21 Nov 2024

Abstract

This paper introduces a control method tailored for the speed regulation of monorail cranes in coal mines. Initially, an analysis of the structure and load conditions of the monorail crane drive components is conducted to calculate the traction force, clamping force, and target [...] Read more.

This paper introduces a control method tailored for the speed regulation of monorail cranes in coal mines. Initially, an analysis of the structure and load conditions of the monorail crane drive components is conducted to calculate the traction force, clamping force, and target travel speed across varying operational scenarios. Subsequently, the hydraulic system schematic of the monorail crane is analyzed to develop a mathematical model for speed control, enabling the assessment of system stability using transfer functions. A simulation model of the monorail crane speed control loop is then created in AMESim, where fuzzy adaptive PID controllers and MPC controllers are optimized in a collaborative simulation with Simulink. Experimental findings reveal that in a single acceleration condition, both controllers demonstrate superior dynamic response compared to a traditional PID controller, with the MPC controller exhibiting an overshoot of merely 8.9%. In speed variation conditions, the MPC controller achieved a settling time in the range of 0.26–0.3 s. Notably, the MPC controller displays a maximum overshoot of 11%, substantially enhancing the dynamic response performance of speed regulation in monorail cranes. Full article

(This article belongs to the Special Issue Intelligent and Precision Control for Mechatronic/Electro-Hydraulic Systems)

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18 pages, 15595 KiB

Open AccessArticle

Vehicle Attitude Control of Magnetorheological Semi-Active Suspension Based on Multi-Objective Intelligent Optimization Algorithm

by Kailiang Han, Yiming Hu, Dequan Zeng, Yinquan Yu, Lei Xiao, Jinwen Yang, Weidong Liu and Letian Gao

Actuators 2024, 13(12), 466; https://doi.org/10.3390/act13120466 - 21 Nov 2024

Abstract

A multi-objective intelligent optimization algorithm-based attitude control strategy for magnetorheological semi-active suspension is proposed to address the vehicle attitude imbalance generated during steering and braking. Firstly, the mechanical properties of the magnetorheological damper (MRD) are tested, and the parameters in the hyperbolic tangent [...] Read more.

A multi-objective intelligent optimization algorithm-based attitude control strategy for magnetorheological semi-active suspension is proposed to address the vehicle attitude imbalance generated during steering and braking. Firstly, the mechanical properties of the magnetorheological damper (MRD) are tested, and the parameters in the hyperbolic tangent model of the magnetorheological damper are identified through experiments. Secondly, a simulation model of the whole vehicle multi-degree-of-freedom vehicle dynamics including magnetorheological damper is established, and the whole-vehicle Linear Quadratic Regulator (LQR) controller is designed. Then, the optimization design model of the joint vehicle controller and vehicle dynamics is established to design the optimization fitness function oriented to the body attitude control performance, and the attitude optimal controller is calculated with the help of multi-objective intelligent optimization algorithm. Simulation results show that the proposed control method is able to improve the body roll angle, body pitch angle, and suspension dynamic deflection well on the basis of ensuring no deterioration in other performance indexes, ensuring good attitude control capability of the vehicle and verifying the feasibility of the control strategy. Full article

(This article belongs to the Special Issue Magnetorheological Actuators and Dampers)

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12 pages, 3356 KiB

Open AccessArticle

The Potential of Shape Memory Alloys in Riveting Applications

by Edgar Camacho, Patrícia Freitas Rodrigues and Francisco Manuel Braz Fernandes

Actuators 2024, 13(11), 465; https://doi.org/10.3390/act13110465 - 20 Nov 2024

Abstract

This study explores the use of shape memory alloys, specifically nickel-titanium (NiTi- Ti-rich), in plate joining processes through riveting. Through the shape memory effect (SME), SMAs offer innovative solutions for joining components, mainly in the aeronautical and aerospace fields, indicating their promising applications. [...] Read more.

This study explores the use of shape memory alloys, specifically nickel-titanium (NiTi- Ti-rich), in plate joining processes through riveting. Through the shape memory effect (SME), SMAs offer innovative solutions for joining components, mainly in the aeronautical and aerospace fields, indicating their promising applications. This research presents several characterizations, including differential scanning calorimetry, compression dilatometry, X-ray diffraction using synchrotron radiation, and thermomechanical testing, to assess the feasibility and performance of shape memory alloy rivets. In addition, the samples were subjected to recrystallization heat treatment to evaluate their reusability. The results demonstrated that shape memory alloy rivets are effective, achieving a maximum load of 340 N for two joined components. However, their application is optimal for materials with yield strengths lower than the stress-induced SME. Moreover, the process enhances the joined components’ hardening and increases the rivet’s thermal hysteresis. This research confirms the viability of shape memory alloys for riveting processes, offering a new avenue for advanced joining techniques. The findings provide a foundation for their further development and application in various industries requiring precise and reliable joining methods. Full article

(This article belongs to the Special Issue Shape Memory Alloys and Piezoelectric Materials and Their Applications—2nd Edition)

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22 pages, 9463 KiB

Open AccessArticle

A Novel Chaotic Particle Swarm Optimized Backpropagation Neural Network PID Controller for Four-Switch Buck–Boost Converters

by Luoyao Ren, Dazhi Wang, Xin Yan, Yupeng Zhang and Jiaxing Wang

Actuators 2024, 13(11), 464; https://doi.org/10.3390/act13110464 - 19 Nov 2024

Abstract

The emergence of intelligent control strategies has made optimization techniques essential for the precise control of DC converters. This study aims to enhance the performance of the Four-Switch Buck–Boost (FSBB) converter through control system optimization. Backpropagation neural networks (BPNNs) have been widely used [...] Read more.

The emergence of intelligent control strategies has made optimization techniques essential for the precise control of DC converters. This study aims to enhance the performance of the Four-Switch Buck–Boost (FSBB) converter through control system optimization. Backpropagation neural networks (BPNNs) have been widely used for optimizing proportional–integral–derivative (PID) controllers. To further improve the FSBB control system, particle swarm optimization (PSO) is employed to optimize the BPNN, reducing dynamic response time and enhancing robustness. Despite these advantages, the PSO method still suffers from limitations, such as slow convergence and poor stability. To address these challenges, chaotic optimization algorithms are integrated with BPNN. The chaotic particle swarm optimization (CPSO) algorithm enhances the global search capability, enabling a faster system response and minimizing overvoltage. This hybrid CPSO-BPNN approach refines the optimization process, leading to more precise control of the FSBB converter. The simulation results show that the CPSO-BPNN-PID controller reaches a steady state more quickly and exhibits superior performance compared to traditional PID controllers. Full article

(This article belongs to the Section Control Systems)

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13 pages, 5359 KiB

Open AccessArticle

Displaying Tactile Sensation by SMA-Driven Vibration and Controlled Temperature for Cutaneous Sensation Assessment

by Tomohiro Nozawa, Renke Liu and Hideyuki Sawada

Actuators 2024, 13(11), 463; https://doi.org/10.3390/act13110463 - 18 Nov 2024

Abstract

In this paper, we propose a novel tactile display that can present vibration patterns and thermal stimuli simultaneously. The vibration actuator employs a shape memory alloy (SMA) wire to generate micro-vibration with a frequency control of up to 300 Hz. The micro-vibration is [...] Read more.

In this paper, we propose a novel tactile display that can present vibration patterns and thermal stimuli simultaneously. The vibration actuator employs a shape memory alloy (SMA) wire to generate micro-vibration with a frequency control of up to 300 Hz. The micro-vibration is conducted to a tactile pin for amplifying the vibration, to be sufficiently recognized by a user. A thermal stimulation unit, on the other hand, consists of four Peltier elements with heatsinks for heat radiation. Four vibration actuators and a thermal unit are arranged in a flat plane with a size of 20 mm × 20 mm, on which a user places the tip of an index finger to feel the presented vibratory stimuli under different temperature conditions. We conducted an experiment by employing nine subjects to evaluate the performance of the proposed tactile display and also to investigate the effects of temperature on recognizing tactile sensation. The results demonstrated that the proposed device was feasible for the quantitative diagnosis of tactile sensation. In addition, we verified that the sensitivity of tactile sensation decreased with colder stimuli. Full article

(This article belongs to the Special Issue Innovative Actuators Based on Shape Memory Alloys)

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15 pages, 17738 KiB

Open AccessArticle

Assessing the Impact of Force Feedback in Musical Knobs on Performance and User Experience

by Ziyue Piao, Christian Frisson, Bavo Van Kerrebroeck and Marcelo M. Wanderley

Actuators 2024, 13(11), 462; https://doi.org/10.3390/act13110462 - 16 Nov 2024

Abstract

This paper examined how rotary force feedback in knobs can enhance control over musical techniques, focusing on both performance and user experience. To support our study, we developed the Bend-aid system, a web-based sequencer with pre-designed haptic modes for pitch modulation, integrated with [...] Read more.

This paper examined how rotary force feedback in knobs can enhance control over musical techniques, focusing on both performance and user experience. To support our study, we developed the Bend-aid system, a web-based sequencer with pre-designed haptic modes for pitch modulation, integrated with TorqueTuner, a rotary haptic device that controls pitch through programmable haptic effects. Then, twenty musically trained participants evaluated three haptic modes (No-force feedback (No-FF), Spring, and Detent) by performing a vibrato mimicry task, rating their experience on a Likert scale, and providing qualitative feedback in post-experiment interviews. The study assessed objective performance metrics (Pitch Error and Pitch Deviation) and subjective user experience ratings (Comfort, Ease of Control, and Helpfulness) of each haptic mode. User experience results showed that participants found force feedback helpful. Performance results showed that the Detent mode significantly improved pitch accuracy and vibrato stability compared to No-FF, while the Spring mode did not show a similar improvement. Post-experiment interviews showed that preferences for Spring and Detent modes varied, and the applicants provided suggestions for future knob designs. These findings suggest that force feedback may enhance both control and the experience of control in rotary knobs, with potential applications for more nuanced control in DMIs. Full article

(This article belongs to the Special Issue Actuators for Haptic and Tactile Stimulation Applications)

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28 pages, 13483 KiB

Open AccessReview

Review of Key Technologies for Aviation Intelligent Pumps

by Xudong Han, Yan Wang, Liming Yu, Yongling Fu and Deming Zhu

Actuators 2024, 13(11), 461; https://doi.org/10.3390/act13110461 - 15 Nov 2024

Abstract

The airborne intelligent hydraulic system is an effective way to solve the ineffective power consumption and temperature rise of an aircraft hydraulic system. An intelligent pump that can work in a variety of modes according to the change of flight conditions is an [...] Read more.

The airborne intelligent hydraulic system is an effective way to solve the ineffective power consumption and temperature rise of an aircraft hydraulic system. An intelligent pump that can work in a variety of modes according to the change of flight conditions is an inevitable requirement for the realization of airborne intelligent hydraulic system, and it is also the development trend of aviation pumps in the future. In this paper, key technologies for aviation intelligent pumps are reviewed. This paper briefly describes its development process and summarizes the research on aviation intelligent pumps from the aspects of the system scheme, working mode, structure form, and control strategy. Finally, the conclusions and trends of the research status of intelligent pumps are given, which can provide a reference for subsequent research on further improving the performance of aviation intelligent pumps. Full article

(This article belongs to the Section Aircraft Actuators)

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13 pages, 6930 KiB

Open AccessArticle

Development of Electro-Mechanical Actuator for Wheel Steering of Railway Vehicles

by Hyun Moo Hur, Jung Won Seo, Kyung Ho Moon and Jong Hyun Choi

Actuators 2024, 13(11), 460; https://doi.org/10.3390/act13110460 - 15 Nov 2024

Abstract

We developed an electro-mechanical actuator for use as a steering device for railway vehicles. The specifications for a 50 kN-class electro-mechanical actuator capable of steering control for a sharp of a railway radius curve of up to 250 m, and with Direct Drive [...] Read more.

We developed an electro-mechanical actuator for use as a steering device for railway vehicles. The specifications for a 50 kN-class electro-mechanical actuator capable of steering control for a sharp of a railway radius curve of up to 250 m, and with Direct Drive motor (DD motor) specifications, were derived as a power source to drive it. The DD motor and an electric mechanical steering actuator equipped with it were designed and a prototype was manufactured. As a result of testing laboratory tests on motor and actuator prototypes, all performance requirements were satisfied. We conducted a field test on the actuator prototype by installing it on a railway vehicle to verify the steering angle performance. The steering action of the actuator worked well when running in curved sections, and the steering angles measured for each curve were in line with the target steering angles. The mean error between the target steering angle and the measured steering angle was only 3.4%, indicating that the wheel steering action of the developed steering system was working very well. Therefore, the developed electro-mechanical actuator is expected to be fully utilized as a steering device for railway vehicles by meeting all the performance requirements of the steering system. Full article

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

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19 pages, 5103 KiB

Open AccessArticle

Dual-Sliding-Surface Robust Control for the PEMFC Air-Feeding System Based on Terminal Sliding Mode Algorithm

by Shiyi Fang, Jianan Feng, Xinyu Fan, Daifen Chen and Cao Tan

Actuators 2024, 13(11), 459; https://doi.org/10.3390/act13110459 - 15 Nov 2024

Abstract

The proton exchange membrane fuel cell (PEMFC) is the most widely used fuel cell, but it also has some limitations. One of the research pain points is controlling the oxygen content in PEMFCs. A moderate excess of oxygen boosts electrochemical reaction efficiency, while [...] Read more.

The proton exchange membrane fuel cell (PEMFC) is the most widely used fuel cell, but it also has some limitations. One of the research pain points is controlling the oxygen content in PEMFCs. A moderate excess of oxygen boosts electrochemical reaction efficiency, while an appropriate oxygen content ensures system stability. In this paper, a fourth-order nonlinear mathematical model of a PEMFC stack air supply system is established to solve the problem of optimal oxygen excess ratio (OER) control under dynamic load conditions. Based on the model, a nonsingular terminal sliding mode controller (NTSMC) based on a sliding mode observer (SMO) is proposed. The NTSM exhibits superior robustness and performance compared to other sliding mode structures. Meanwhile, the SMO accurately predicts system states, facilitating precise control actions. Additionally, the dual sliding mode surfaces enhance system stability against parameter uncertainties and external disturbances. Our results demonstrate that the proposed controller outperforms traditional ones in terms of robustness and performance, which significantly enhances PEMFC system efficiency and stability. Full article

(This article belongs to the Section Control Systems)

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18 pages, 11599 KiB

Open AccessArticle

Path Planning for Robots Combined with Zero-Shot and Hierarchical Reinforcement Learning in Novel Environments

by Liwei Mei and Pengjie Xu

Actuators 2024, 13(11), 458; https://doi.org/10.3390/act13110458 - 15 Nov 2024

Abstract

Path planning for robots based on reinforcement learning encounters challenges in integrating semantic information about environments into the training process. In unseen or complex environmental information, agents often perform sub-optimally and require more training time. In response to these challenges, this manuscript pioneers [...] Read more.

Path planning for robots based on reinforcement learning encounters challenges in integrating semantic information about environments into the training process. In unseen or complex environmental information, agents often perform sub-optimally and require more training time. In response to these challenges, this manuscript pioneers a framework integrating zero-shot learning combined with hierarchical reinforcement learning to enhance agent decision-making in complex environments. Zero-shot learning enables agents to infer correct actions for previously unseen objects or situations based on learned semantic associations. Subsequently, the path planning component utilizes hierarchical reinforcement learning with adaptive replay buffer, directed by the insights gained from zero-shot learning, to make decisions effectively. Two parts are trained separately, so zero-shot learning is available in different and unseen environments. Through simulation experiments, we compare the traditional hierarchical reinforcement learning method with the proposed method. The results prove that this structure can make full use of environmental information to generalize across unseen environments and plan collision-free paths. Full article

(This article belongs to the Section Actuators for Land Transport)

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15 pages, 18745 KiB

Open AccessArticle

Robust Adaptive Robotic Visual Servo Grasping with Guaranteed Field of View Constraints

by Liang Li, Junqi Luo, Peitao Hong, Wenhao Bai, Zhenyu Zhang and Liucun Zhu

Actuators 2024, 13(11), 457; https://doi.org/10.3390/act13110457 - 14 Nov 2024

Abstract

Visual servo grasping technology has garnered significant attention in intelligent manufacturing for its potential to enhance both the flexibility and precision of robotic operations. However, traditional approaches frequently encounter challenges such as task failure when visual features move outside the camera’s field of [...] Read more.

Visual servo grasping technology has garnered significant attention in intelligent manufacturing for its potential to enhance both the flexibility and precision of robotic operations. However, traditional approaches frequently encounter challenges such as task failure when visual features move outside the camera’s field of view (FoV) and system instability due to interaction matrix singularities, limiting the technology’s effectiveness in complex environments. This study introduces a novel control strategy that leverages an asymmetric time-varying performance function to address the issue of visual feature escape. By strictly limiting the range of feature error, our approach ensures that visual features consistently remain within the camera’s FoV, thereby enhancing both transient and steady-state system performance. Furthermore, we have developed an adaptive damped least squares controller that dynamically adjusts the damping term to mitigate numerical instability resulting from interaction matrix singularities. The effectiveness of our method has been validated through grasping experiments involving significant rotations around the camera’s optical axis and other complex movements. Full article

(This article belongs to the Section Actuators for Robotics)

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18 pages, 5097 KiB

Open AccessArticle

An Interpolator for a Non-Uniform Rational B-Spline Curve with a High Efficiency and Accuracy Using Polynomial Representations

by Zhuiliang Huang and Jianxiong Chen

Actuators 2024, 13(11), 456; https://doi.org/10.3390/act13110456 - 13 Nov 2024

Abstract

This paper introduces an efficient and accurate interpolator for NURBS (non-uniform rational B-spline) curves, addressing the challenge of regulating feedrate under machining accuracy and dynamic constraints, particularly at sensitive corners. A recursive matrix representation and polynomial conversion are utilized to enhance the computation [...] Read more.

This paper introduces an efficient and accurate interpolator for NURBS (non-uniform rational B-spline) curves, addressing the challenge of regulating feedrate under machining accuracy and dynamic constraints, particularly at sensitive corners. A recursive matrix representation and polynomial conversion are utilized to enhance the computation of NURBS curve intermediate points and derivatives. An improved adaptive planning method is presented to adjust the feedrate at sensitive corners, ensuring that chord error and dynamic constraints are met. The method integrates linear acceleration and deceleration stages to mitigate abrupt changes in acceleration and jerk. Additionally, a prediction–correction scheme-based interpolator is developed, employing an asynchronous mechanism to improve computational efficiency. The proposed method’s effectiveness and correctness are validated through simulation tests and machining experiments. Full article

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

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36 pages, 5740 KiB

Open AccessReview

PEMFC Gas-Feeding Control: Critical Insights and Review

by Shiyi Fang, Jianan Feng, Xinyu Fan, Daifen Chen and Cao Tan

Actuators 2024, 13(11), 455; https://doi.org/10.3390/act13110455 - 13 Nov 2024

Abstract

Proton exchange membrane fuel cells (PEMFCs) are currently a relatively mature type of hydrogen energy device due to their high efficiency and low noise compared to traditional power devices. However, there are still challenges that hinder the large-scale application of PEMFCs. One key [...] Read more.

Proton exchange membrane fuel cells (PEMFCs) are currently a relatively mature type of hydrogen energy device due to their high efficiency and low noise compared to traditional power devices. However, there are still challenges that hinder the large-scale application of PEMFCs. One key challenge lies in the gas supply system, which is a complex, coupled nonlinear system. Therefore, an effective control strategy is essential for the efficient and stable operation of the gas control system. This paper aims to provide a comprehensive and systematic overview of the control strategies for PEMFC anode and cathode supply systems based on an analysis of 182 papers. The review covers modern control theories and optimization algorithms, including their design, objectives, performance, applications, and so on. Additionally, the advantages and disadvantages of these control methods are thoroughly evaluated and summarized. Full article

(This article belongs to the Section Control Systems)

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15 pages, 3407 KiB

Open AccessArticle

Minimalist Design for Multi-Dimensional Pressure-Sensing and Feedback Glove with Variable Perception Communication

by Hao Ling, Jie Li, Chuanxin Guo, Yuntian Wang, Tao Chen and Minglu Zhu

Actuators 2024, 13(11), 454; https://doi.org/10.3390/act13110454 - 13 Nov 2024

Abstract

Immersive human–machine interaction relies on comprehensive sensing and feedback systems, which enable transmission of multiple pieces of information. However, the integration of increasing numbers of feedback actuators and sensors causes a severe issue in terms of system complexity. In this work, we propose [...] Read more.

Immersive human–machine interaction relies on comprehensive sensing and feedback systems, which enable transmission of multiple pieces of information. However, the integration of increasing numbers of feedback actuators and sensors causes a severe issue in terms of system complexity. In this work, we propose a pressure-sensing and feedback glove that enables multi-dimensional pressure sensing and feedback with a minimalist design of the functional units. The proposed glove consists of modular strain and pressure sensors based on films of liquid metal microchannels and coin vibrators. Strain sensors located at the finger joints can simultaneously project the bending motion of the individual joint into the virtual space or robotic hand. For subsequent tactile interactions, the design of two symmetrically distributed pressure sensors and vibrators at the fingertips possesses capabilities for multi-directional pressure sensing and feedback by evaluating the relationship of the signal variations between two sensors and tuning the feedback intensities of two vibrators. Consequently, both dynamic and static multi-dimensional pressure communication can be realized, and the vibrational actuation can be monitored by a liquid-metal-based sensor via a triboelectric sensing mechanism. A demonstration of object interaction indicates that the proposed glove can effectively detect dynamic force in varied directions at the fingertip while offering the reconstruction of a similar perception via the haptic feedback function. This device introduces an approach that adopts a minimalist design to achieve a multi-functional system, and it can benefit commercial applications in a more cost-effective way. Full article

(This article belongs to the Special Issue Advanced Actuation, Intelligent Sensor and Precise Manipulation Technology in Human–Robot Interaction)

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14 pages, 6557 KiB

Open AccessArticle

Design, Modeling, and Characteristics Analysis of Halbach Permanent Magnetic Spring

by Yuexuan Lou, He Zhang and Haoran Cai

Actuators 2024, 13(11), 453; https://doi.org/10.3390/act13110453 - 12 Nov 2024

Abstract

Magnetic springs, which can be used to replace traditional mechanical springs, have many advantages, such as necessitating no physical contact, generating no friction, no vibration or noise, and having a long lifespan. Nevertheless, their strong nonlinearity limits their widespread application. In this study, [...] Read more.

Magnetic springs, which can be used to replace traditional mechanical springs, have many advantages, such as necessitating no physical contact, generating no friction, no vibration or noise, and having a long lifespan. Nevertheless, their strong nonlinearity limits their widespread application. In this study, we developed a novel permanent magnet spring to address this issue: a Halbach permanent magnetic spring, with a large levitation force and an approximately linear force characteristic curve. First, we introduce the structure and the parameters of the Halbach permanent magnetic spring. Second, we describe the levitation force performance and the stiffness performance of the Halbach permanent magnetic spring using finite element analysis. Third, we analyze the trends through which different parameters influence the levitation force performance and stiffness performance. Finally, we provide recommendations for the future design of and improvement in the Halbach permanent magnetic spring. Full article

(This article belongs to the Special Issue Advanced Theory and Application of Magnetic Actuators—2nd Edition)

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