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Actuators
Volume 13
Issue 4
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Actuators, Volume 13, Issue 4 (April 2024) – 39 articles

Cover Story (view full-size image): Soft fiber-reinforced actuators have demonstrated significant potential across various robotics applications. However, their actuation motion is typically limited to a single type of motion behavior. This paper presents two novel hybrid actuators in which shape memory alloy (SMA) wires are used as reinforcement for pneumatic actuation, and upon electrical activation, they create twisting motion. As a result, the hybrid soft SMA-reinforced actuators can select between twisting and bending or twisting and extending. The resulting pneumatic–electric-driven soft actuators enhance dexterity and versatility, making them suitable for applications in walking robots, in-pipe crawling robots, and in-hand manipulation. View this paper
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19 pages, 7110 KiB  
Article
Deployable Structures Based on Non-Flat-Foldable and Non-Developable Origami with Constant Curvature
by Bo Qin, Shiwei Liu, Jianzhi Wang and Shengnan Lyu
Actuators 2024, 13(4), 156; https://doi.org/10.3390/act13040156 - 19 Apr 2024
Viewed by 268
Abstract
Deployable structures based on origami are widely used in the application of actuators. In this paper, we present a novel family of origami-based deployable structures with constant curvature. Two categories of non-flat-foldable and non-developable degree-4 vertices (NFND degree-4 vertices) are introduced. Pyramid structures [...] Read more.
Deployable structures based on origami are widely used in the application of actuators. In this paper, we present a novel family of origami-based deployable structures with constant curvature. Two categories of non-flat-foldable and non-developable degree-4 vertices (NFND degree-4 vertices) are introduced. Pyramid structures are constructed based on the NFND degree-4 vertices. Doubly symmetric and singly symmetric spherical origami tubular cells (SOTCs) are established based on pyramid structures. To construct deployable origami modules using SOTCs, linking units are introduced. The mobility of the SOTCs and origami modules is analyzed using constraint screws. To realize the construction and simulation of deployable structures, kinematic and geometric analyses of the doubly symmetric and singly symmetric SOTCs are performed. Finally, we introduce four cases for deployable structures in spherical actuators based on the combination of multiple origami modules. These case studies demonstrate the potential of these deployable origami structures in the design of spherical actuators. Full article
(This article belongs to the Special Issue Actuators in 2024)
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15 pages, 6302 KiB  
Article
A New Rotary Magnetorheological Damper for a Semi-Active Suspension System of Low-Floor Vehicles
by Yu-Jin Park, Byung-Hyuk Kang and Seung-Bok Choi
Actuators 2024, 13(4), 155; https://doi.org/10.3390/act13040155 - 18 Apr 2024
Viewed by 306
Abstract
This study explores the significance of active suspension systems for vehicles with lower chassis compared to conventional ones, aiming at the development of future automobiles. Conventional linear MR (magnetorheological) dampers were found inadequate in ensuring sufficient vibration control because the vehicle’s chassis becomes [...] Read more.
This study explores the significance of active suspension systems for vehicles with lower chassis compared to conventional ones, aiming at the development of future automobiles. Conventional linear MR (magnetorheological) dampers were found inadequate in ensuring sufficient vibration control because the vehicle’s chassis becomes lowered in the unmanned vehicles or purposed-based vehicles. As an alternative, a rotary type of MR damper is proposed in this work. The proposed damper is designed based on prespecified design parameters through mathematical modeling and magnetic field analyses. Subsequently, a prototype of the rotary MR damper identical to the design is fabricated, and effectiveness is shown through experimental investigations. In configuring the experiments, a proportional-integral (PI) controller is employed for current control to reduce the response time of the damper. The results presented in this work provide useful guidelines to develop a new type of MR damper applicable to various types of future vehicles’ suspension systems with low distance from the tire to the body floor. Full article
(This article belongs to the Special Issue Actuators and Dampers for Vibration Control: Damping and Isolation Applications - Volume II)
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16 pages, 4207 KiB  
Article
Quadcopter Trajectory Tracking Control Based on Flatness Model Predictive Control and Neural Network
by Yong Li, Qidan Zhu and Ahsan Elahi
Actuators 2024, 13(4), 154; https://doi.org/10.3390/act13040154 - 18 Apr 2024
Viewed by 271
Abstract
In this paper, a novel control architecture is proposed in which FMPC couples feedback from model predictive control with feedforward linearization. The proposed approach has the computational advantage of only requiring a convex quadratic program to be solved instead of a nonlinear program. [...] Read more.
In this paper, a novel control architecture is proposed in which FMPC couples feedback from model predictive control with feedforward linearization. The proposed approach has the computational advantage of only requiring a convex quadratic program to be solved instead of a nonlinear program. Feedforward linearization aims to overcome the robustness issues of feedback linearization, which may be the result of parametric model uncertainty leading to inexact pole-zero cancellation. A DenseNet was trained to learn the inverse dynamics of the system, and it was used to adjust the desired path input for FMPC. Through experiments using quadcopter, we also demonstrated improved trajectory tracking performance compared to that of the PD, FMPC, and FMPC+DNN approaches. The root mean square (RMS) error was used to evaluate the performance of the above four methods. The results demonstrate that the proposed method is effective. Full article
(This article belongs to the Special Issue Fault-Tolerant Control for Unmanned Aerial Vehicles (UAVs))
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34 pages, 11051 KiB  
Article
Integrated Spatial Kinematics–Dynamics Model Predictive Control for Collision-Free Autonomous Vehicle Tracking
by Weishan Yang, Yixin Su, Yuepeng Chen and Cheng Lian
Actuators 2024, 13(4), 153; https://doi.org/10.3390/act13040153 - 18 Apr 2024
Viewed by 285
Abstract
The development of intelligent transportation technology has provided a significant impetus for autonomous driving technology. Currently, autonomous vehicles based on Model Predictive Control (MPC) employ motion control strategies based on sampling time, which fail to fully utilize the spatial information of obstacles. To [...] Read more.
The development of intelligent transportation technology has provided a significant impetus for autonomous driving technology. Currently, autonomous vehicles based on Model Predictive Control (MPC) employ motion control strategies based on sampling time, which fail to fully utilize the spatial information of obstacles. To address this issue, this paper proposes a dual-layer MPC vehicle collision-free trajectory tracking control strategy that integrates spatial kinematics and vehicle dynamics. To fully utilize the spatial information of obstacles, we designed a vehicle model based on spatial kinematics, enabling the upper-layer MPC to plan collision avoidance trajectories based on distance sampling. To improve the accuracy and safety of trajectory tracking, we designed an 8-degree-of-freedom vehicle dynamic model. This allows the lower-layer MPC to consider lateral stability and roll stability during trajectory tracking. In collision avoidance trajectory tracking experiments using three scenarios, compared to two advanced time-based algorithms, the trajectories planned by the proposed algorithm in this paper exhibited predictability. The proposed algorithm can initiate collision avoidance at predetermined positions and can avoid collisions in predetermined directions, with all state variables within safe ranges. In terms of time efficiency, it also outperformed the comparative algorithms. Full article
(This article belongs to the Special Issue Advances in Dynamics and Motion Control of Unmanned Aerial/Underwater/Ground Vehicles)
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21 pages, 4986 KiB  
Article
Optimization Approach for Multisensory Feedback in Robot-Assisted Pouring Task
by Mandira S. Marambe, Bradley S. Duerstock and Juan P. Wachs
Actuators 2024, 13(4), 152; https://doi.org/10.3390/act13040152 - 18 Apr 2024
Viewed by 318
Abstract
Individuals with disabilities and persons operating in inaccessible environments can greatly benefit from the aid of robotic manipulators in performing daily living activities and other remote tasks. Users relying on robotic manipulators to interact with their environment are restricted by the lack of [...] Read more.
Individuals with disabilities and persons operating in inaccessible environments can greatly benefit from the aid of robotic manipulators in performing daily living activities and other remote tasks. Users relying on robotic manipulators to interact with their environment are restricted by the lack of sensory information available through traditional operator interfaces. These interfaces deprive users of somatosensory feedback that would typically be available through direct contact. Multimodal sensory feedback can bridge these perceptual gaps effectively. Given a set of object properties (e.g., temperature, weight) to be conveyed and sensory modalities (e.g., visual, haptic) available, it is necessary to determine which modality should be assigned to each property for an effective interface design. The goal of this study was to develop an effective multisensory interface for robot-assisted pouring tasks, which delivers nuanced sensory feedback while permitting the high visual demand necessary for precise teleoperation. To that end, an optimization approach was employed to generate a combination of feedback properties to modality assignments that maximizes effective feedback perception and minimizes cognitive load. A set of screening experiments tested twelve possible individual assignments to form this optimal combination. The resulting perceptual accuracy, load, and user preference measures were input into a cost function. Formulating and solving as a linear assignment problem, a minimum cost combination was generated. Results from experiments evaluating efficacy in practical use cases for pouring tasks indicate that the solution was significantly more effective than no feedback and had considerable advantage over an arbitrary design. Full article
(This article belongs to the Special Issue Rehabilitation Robots and Assistive Devices: A Special Issue in Honor of Prof. Dr. Rory A. Cooper)
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36 pages, 2377 KiB  
Review
Dielectric Elastomer-Based Actuators: A Modeling and Control Review for Non-Experts
by Hector Medina, Carson Farmer and Isaac Liu
Actuators 2024, 13(4), 151; https://doi.org/10.3390/act13040151 - 17 Apr 2024
Viewed by 456
Abstract
Soft robotics are attractive to researchers and developers due to their potential for biomimicry applications across a myriad of fields, including biomedicine (e.g., surgery), the film industry (e.g., animatronics), ecology (e.g., physical ‘animats’), human–robot interactions (e.g., social robots), and others. In contrast to [...] Read more.
Soft robotics are attractive to researchers and developers due to their potential for biomimicry applications across a myriad of fields, including biomedicine (e.g., surgery), the film industry (e.g., animatronics), ecology (e.g., physical ‘animats’), human–robot interactions (e.g., social robots), and others. In contrast to their rigid counterparts, soft robotics offer obvious actuation benefits, including their many degrees of freedom in motion and their potential to mimic living organisms. Many material systems have been proposed and used for soft robotic applications, involving soft actuators, sensors, and generators. This review focuses on dielectric elastomer (DE)-based actuators, which are more general electro-active polymer (EAP) smart materials. EAP-based soft robots are very attractive for various reasons: (a) energy can be efficiently (and readily) stored in electrical form; (b) both power and information can be transferred rapidly via electrical phenomena; (c) computations using electronic means are readily available. Due to their potential and benefits, DE-based actuators are attractive to researchers and developers from multiple fields. This review aims to (1) provide non-experts with an “easy-to-follow” survey of the most important aspects and challenges to consider when implementing DE-based soft actuators, and (2) emphasize current solutions and challenges related to the materials, controls, and portability of DE-based soft-actuator systems. First, we start with some fundamental functions, applications, and configurations; then, we review the material models and their selection. After, we outline material limitations and challenges along with some thermo-mechano-chemical treatments to overcome some of those limitations. Finally, we outline some of the control schemes, including modern techniques, and suggest using rewritable hardware for faster and more adaptive controls. Full article
(This article belongs to the Special Issue Actuators in 2024)
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16 pages, 3399 KiB  
Article
Progressive Optimal Fault-Tolerant Control Combining Active and Passive Control Manners
by Dan Du, Zetao Li and Boutaib Dahhou
Actuators 2024, 13(4), 150; https://doi.org/10.3390/act13040150 - 16 Apr 2024
Viewed by 279
Abstract
This study develops a progressive optimal fault-tolerant control method based on insufficient fault information. By combining passive and active fault-tolerant control manners during the process of fault diagnosis, insufficient fault information is fully used, and optimal fault-tolerant control effect is achieved. In addition, [...] Read more.
This study develops a progressive optimal fault-tolerant control method based on insufficient fault information. By combining passive and active fault-tolerant control manners during the process of fault diagnosis, insufficient fault information is fully used, and optimal fault-tolerant control effect is achieved. In addition, the fault-tolerant control method based on guaranteed robust cost control is introduced. The proposed progressive optimal fault-tolerant control method considers two aspects. First, as the amount of fault information continually increases, the performance index of the progressive optimal fault-tolerant controller improves. Second, at each moment, based on the corresponding insufficient fault information and prior knowledge, optimal fault-tolerant control is achieved according to current fault information. The process of progressive optimal fault-tolerant control converges to active fault-tolerant control when the fault is completely identified, and the optimal fault-tolerant controller is no longer reconfigured until no more useful fault information can be provided. Furthermore, a progressive optimal fault-tolerant control algorithm based on the grid segmentation in the parameter uncertainty domain and the selection of different auxiliary center points is introduced. Simulation results verified the feasibility of the proposed algorithm and the validity of the proposed theory. Full article
(This article belongs to the Section Control Systems)
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18 pages, 9671 KiB  
Article
Development of a Tool to Manipulate Flexible Pieces in the Industry: Hardware and Software
by Francisco José Martínez-Peral, Jorge Borrell Méndez, José Vicente Segura Heras and Carlos Perez-Vidal
Actuators 2024, 13(4), 149; https://doi.org/10.3390/act13040149 - 16 Apr 2024
Viewed by 479
Abstract
Currently, the textile industry is a poorly automated sector, due in part to problems in the handling of deformable leather and textile parts during production operations. In this work, several problems in the handling process of leather and textile parts are addressed, introducing [...] Read more.
Currently, the textile industry is a poorly automated sector, due in part to problems in the handling of deformable leather and textile parts during production operations. In this work, several problems in the handling process of leather and textile parts are addressed, introducing methods to increase the automation of the process. A pneumatic actuator designed to pick up textile or leather parts avoiding their deformation during transport has been developed. This actuator maximizes the number of gripping points to improve handling, making it more stable and efficient. Additionally, a vision system has been implemented in the part-picking task which, in conjunction with the CAD information of the part, sends the modified gripping position of the part to the robot. This allows customized handling of each textile or leather part. Finally, validation tests have been carried out on this development, both in simulations and in laboratory conditions, demonstrating its viability and direct applicability in the production line. Full article
(This article belongs to the Section Actuators for Robotics)
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16 pages, 9180 KiB  
Article
Non-Electrically Driven Acoustic Actuator
by Takeru Niwano and Mitsuharu Matsumoto
Actuators 2024, 13(4), 148; https://doi.org/10.3390/act13040148 - 16 Apr 2024
Viewed by 479
Abstract
Nuclear power plants have high radiation levels and humans cannot work directly on them. Therefore, it is necessary to establish effective repair work methods. One promising approach is the use of disaster relief robots. However, strong radiation affects circuits and electronic devices. Because [...] Read more.
Nuclear power plants have high radiation levels and humans cannot work directly on them. Therefore, it is necessary to establish effective repair work methods. One promising approach is the use of disaster relief robots. However, strong radiation affects circuits and electronic devices. Because typical robots contain electrical circuits and are controlled by radio waves, they are difficult to use in highly radioactive environments. In this study, we propose a non-electrically driven acoustic actuator that does not use electronic circuits and is driven by sound waves. To realize this goal, we have investigated a sound wave drive using a cylindrical container. Full article
(This article belongs to the Special Issue Actuators in 2024)
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16 pages, 6814 KiB  
Article
Research on Bearing Mechanism of Spherical Valve Pairs of Axial Piston Pumps
by Shunhai Xu, Chunxiao Zhao, Dian He, Nan Xu, Bin Zhang and Guofang Gong
Actuators 2024, 13(4), 147; https://doi.org/10.3390/act13040147 - 15 Apr 2024
Viewed by 368
Abstract
The hydraulic system drives the cutter head mechanism to realize the excavation of large tunnel boring equipment, which puts forward the technical requirements of high pressure and large flow to the pump source. The traditional small displacement axial piston pump uses a planar [...] Read more.
The hydraulic system drives the cutter head mechanism to realize the excavation of large tunnel boring equipment, which puts forward the technical requirements of high pressure and large flow to the pump source. The traditional small displacement axial piston pump uses a planar valve plate. However, under high flow and heavy load conditions, the planar valve plate configuration is prone to uneven wear due to the high-pressure and -velocity (PV) value and pressure shock, which ultimately affects the reliability of the system. A simulation analysis of the load-bearing characteristics of the spherical valve plate mechanism is conducted. The Computational Fluid Dynamics (CFD) method was used to construct flow field models for different valve plate oil film structures to calculate differences in their load-bearing capacities. Additionally, the reasons for variations in load-bearing characteristics based on the curvature radius of the spherical valve plate were analyzed. The simulation results demonstrate that the spherical valve plate exhibits superior leak and load-bearing performance compared to the traditional flat valve plate. Furthermore, the curvature radius of the spherical valve plate directly affects the pulsation characteristics of the piston pump. Smaller curvature radii increase the contact area of the oil film, resulting in greater fluctuation in oil film load-bearing, whereas larger curvature radii lead to increased oil film leakage. Using simulation calculations on heavy-load, high-displacement axial piston pumps, it is determined that the optimal curvature radius for stable load-bearing is 350 mm. Full article
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14 pages, 10865 KiB  
Article
A Novel Thermal Deformation Self-Stabilization Flexible Connection Mechanism
by Fahui Feng, Zhihang Lin and Hui Tang
Actuators 2024, 13(4), 146; https://doi.org/10.3390/act13040146 - 15 Apr 2024
Viewed by 359
Abstract
In micro-LED chip repair, a nanopositioner is commonly used to adjust the positioning of the LED chip. However, during the bonding process, the heat generated can cause the positioning system to deform, leading to inaccurate alignment and poor-quality chip repair. To solve this [...] Read more.
In micro-LED chip repair, a nanopositioner is commonly used to adjust the positioning of the LED chip. However, during the bonding process, the heat generated can cause the positioning system to deform, leading to inaccurate alignment and poor-quality chip repair. To solve this issue, a novel flexible connection structure has been proposed that can eliminate thermal deformation. The principle of this novel flexible connection structure is that the thermal distortion self-elimination performance is achieved via three flexible connection modules (FCM) so that the thermal stress is automatically eliminated. First, the paper introduces the principle of thermal deformation elimination, and then the design and modeling process of the proposed structure are described. A heat transfer model is then developed to determine how temperature is distributed within the structure. A thermal deformation model is established, and the size of the FCM is optimized using a genetic algorithm (GA) to minimize the thermal deformation. Finite element analysis (FEA) is used to simulate and evaluate the thermal distortion self-elimination performance of the optimized mechanism. Finally, experiments are conducted to verify the reliability and accuracy of the simulation results. The simulations and experiments show that the proposed structure can eliminate more than 38% of the thermal deformation, indicating an excellent thermal deformation self-eliminating capability. Full article
(This article belongs to the Section Actuators for Manufacturing Systems)
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27 pages, 24163 KiB  
Article
Terminal Sliding Mode Force Control Based on Modified Fast Double-Power Reaching Law for Aerospace Electro-Hydraulic Load Simulator of Large Loads
by Yingna Zhao, Cheng Qiu, Jing Huang, Qifan Tan, Shuo Sun and Zheng Gong
Actuators 2024, 13(4), 145; https://doi.org/10.3390/act13040145 - 15 Apr 2024
Viewed by 318
Abstract
This paper addresses the force-tracking problem of aerospace electro-hydraulic load simulators under the influence of high inertia, large loads, and a strong coupling force disturbance. An accurate mathematical model is initially derived to describe the characteristics of the load simulator system, the cause [...] Read more.
This paper addresses the force-tracking problem of aerospace electro-hydraulic load simulators under the influence of high inertia, large loads, and a strong coupling force disturbance. An accurate mathematical model is initially derived to describe the characteristics of the load simulator system, the cause of the surplus force, and the strong phase lag due to large inertia. In order to overcome the position interference of the system and the large phase lag problem, a terminal sliding mode control strategy based on the modified fast double-power reaching law is proposed, based on the accurate mathematical model. This control strategy effectively suppresses the chattering problem of the sliding control and implements the finite time convergence of the system through the design of the reaching law and terminal sliding surface, ensuring the robustness of the system and the accuracy of the force-tracking problem. Finally, a comparison of the simulation and experimental results based on the design of different strategy controllers is performed to verify the effectiveness of the control strategy and system adaptability. Full article
(This article belongs to the Special Issue Flight Control Systems and Dynamic Simulation for Aerospace Applications)
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12 pages, 978 KiB  
Article
Eco-Driving on Hilly Roads in a Mixed Traffic Environment: A Model Predictive Control Approach
by A. S. M. Bakibillah, Md Abdus Samad Kamal, Jun-ichi Imura, Masakazu Mukai and Kou Yamada
Actuators 2024, 13(4), 144; https://doi.org/10.3390/act13040144 - 14 Apr 2024
Viewed by 637
Abstract
Human driving behavior significantly affects vehicle fuel economy and emissions on hilly roads. This paper presents an ecological (eco) driving scheme (EDS) on hilly roads using nonlinear model predictive control (NMPC) in a mixed traffic environment. A nonlinear optimization problem with a relevant [...] Read more.
Human driving behavior significantly affects vehicle fuel economy and emissions on hilly roads. This paper presents an ecological (eco) driving scheme (EDS) on hilly roads using nonlinear model predictive control (NMPC) in a mixed traffic environment. A nonlinear optimization problem with a relevant prediction horizon and a cost function is formulated using variables impacting the fuel economy of vehicles. The EDS minimizes vehicle fuel usage and emissions by generating the optimum velocity trajectory considering the longitudinal motion dynamics, the preceding vehicle’s state, and slope information from the digital road map. Furthermore, the immediate vehicle velocity and angle of the road slope are used to tune the cost function’s weight utilizing fuzzy inference methods for smooth maneuvering on slopes. Microscopic traffic simulations are used to show the effectiveness of the proposed EDS for different penetration rates on a real hilly road in Fukuoka City, Japan, in a mixed traffic environment with the conventional (human-based) driving scheme (CDS). The results show that the fuel consumption and emissions of vehicles are significantly reduced by the proposed NMPC-based EDS compared to the CDS for varying penetration rates. Additionally, the proposed EDS significantly increases the average speed of vehicles on the hilly road. The proposed scheme can be deployed as an advanced driver assistance system (ADAS). Full article
(This article belongs to the Special Issue Advanced Actuation and Control Technologies for Vehicle Driving Systems)
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15 pages, 6137 KiB  
Article
Comparison of Magnetostrictive-Actuated Semi-Active Control Methods Based on Synchronized Switching
by An Li, Yuusuke Kobayashi, Yushin Hara, Keisuke Otsuka and Kanjuro Makihara
Actuators 2024, 13(4), 143; https://doi.org/10.3390/act13040143 - 12 Apr 2024
Viewed by 300
Abstract
Three distinct synchronized switching circuits based on a magnetostrictive actuator are compared in this paper to examine their control mechanisms and circuit characteristics. These circuits include a semi-active shunt circuit, a semi-active current inversion and amplification circuit, and a semi-active automatic current inversion [...] Read more.
Three distinct synchronized switching circuits based on a magnetostrictive actuator are compared in this paper to examine their control mechanisms and circuit characteristics. These circuits include a semi-active shunt circuit, a semi-active current inversion and amplification circuit, and a semi-active automatic current inversion and amplification circuit. Each circuit type employs an additional electronic switch. The synchronized switching method enables the rational control of the circuit current generated by the magnetostrictive actuator to fulfill any desired control strategy. Simulation and experimental results on a 10-bay truss structure reveal that the three circuits can effectively adjust the polarity of the induced current as needed. The three circuits are then compared to thoroughly analyze their unique characteristics and explain their respective advantages and dis-advantages. Using the comparison results, various options available for control circuit design are demonstrated. Full article
(This article belongs to the Special Issue Actuators in 2024)
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26 pages, 5964 KiB  
Article
State Observer-Based Conditioned Reverse-Path Method for Nonlinear System Identification
by Atta Oveisi, Umaaran Gogilan, Jafar Keighobadi and Tamara Nestorović
Actuators 2024, 13(4), 142; https://doi.org/10.3390/act13040142 - 11 Apr 2024
Viewed by 355
Abstract
In light of the complex behavior of vibrating structures, their reliable modeling plays a crucial role in the analysis and system design for vibration control. In this paper, the reverse-path (RP) method is revisited, further developed, and applied to modeling a nonlinear system, [...] Read more.
In light of the complex behavior of vibrating structures, their reliable modeling plays a crucial role in the analysis and system design for vibration control. In this paper, the reverse-path (RP) method is revisited, further developed, and applied to modeling a nonlinear system, particularly with respect to the identification of the frequency response function for a nominal underlying linear system and the determination of the structural nonlinearities. The present approach aims to overcome the requirement for measuring all nonlinear system states all the time during operation. Especially in large-scale systems, this might be a tedious task and often practically infeasible since it would require having individual sensors assigned for each state involved in the design process. In addition, the proper placement and simultaneous operation of a large number of transducers would represent further difficulty. To overcome those issues, we have proposed state estimation in light of the observability criteria, which significantly reduces the number of required sensor elements. To this end, relying on the optimal sensor placement problem, the state estimation process reduces to the solution of Kalman filtering. On this ground, the problem of nonlinear system identification for large-scale systems can be addressed using the observer-based conditioned RP method (OBCRP) proposed in this paper. In contrast to the classical RP method, the current one can potentially handle local and distributed nonlinearities. Moreover, in addition to the state estimation and in comparison to the orthogonal RP method, a new frequency-dependent weighting is introduced in this paper, which results in superior nonlinear system identification performances. Implementation of the method is demonstrated on a multi-degree-of-freedom discretized lumped mass system, representing a substitute model of a physical counterpart used for the identification of the model parameters. Full article
(This article belongs to the Special Issue Actuators and Dampers for Vibration Control: Damping and Isolation Applications - Volume II)
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16 pages, 1685 KiB  
Article
Novel Extension Control Instrument for Power Wheelchair Based on Kalman Filter Head Motion Detection
by Yixin Zhang, Zhuohang Ying, Xinyu Tian, Siyuan Jin, Junjie Huang and Yinan Miao
Actuators 2024, 13(4), 141; https://doi.org/10.3390/act13040141 - 11 Apr 2024
Viewed by 326
Abstract
People with upper limb disabilities or high quadriplegia have extremely high requirements for the maneuverability and functionality of power wheelchairs. Normal wheelchairs cannot meet travel tasks, while smart customized wheelchairs are expensive and cannot be popularized. Therefore, a novel extension control instrument for [...] Read more.
People with upper limb disabilities or high quadriplegia have extremely high requirements for the maneuverability and functionality of power wheelchairs. Normal wheelchairs cannot meet travel tasks, while smart customized wheelchairs are expensive and cannot be popularized. Therefore, a novel extension control instrument for power wheelchairs with low cost, strong scalability, and convenient usage is proposed, which can realize the control of the wheelchair by sensing a change of head posture. The device is divided into a head motion sensing unit (HMSU) and a wheelchair assistance control unit (WACU). The mapping relationship between the head attitude and the subject’s motion intention is established. The inertial measurement module in the HMSU collects the head attitude data and uses the Kalman filtering method to obtain the accurate Euler angle. The WACU is fixed on the original controller of the wheelchair. The joystick is inserted into the extended control mechanism and controlled, instead of the hand, through a 2-degree-of-freedom servo system combined with the pinion and rack push rod structure, thus controlling the movement of the wheelchair. In proceeding, the system can also detect the distance of objects in the environment in real time through the three-direction (front, left, right) ultrasonic ranging sensors installed on the WACU, with a certain obstacle avoidance function. The prototype experiments prove that the extension control instrument developed in this paper based on the Kalman filter can quickly and accurately identify head motion and accurately control the movement of the wheelchair. It is easy to operate and has strong universality, which presents a new low-cost solution for the travel of patients with disabilities. Full article
(This article belongs to the Special Issue Rehabilitation Robots and Assistive Devices: A Special Issue in Honor of Prof. Dr. Rory A. Cooper)
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18 pages, 3983 KiB  
Article
Intelligent Reduced-Dimensional Scheme of Model Predictive Control for Aero-Engines
by Zhen Jiang, Xi Wang, Jiashuai Liu, Nannan Gu and Wei Liu
Actuators 2024, 13(4), 140; https://doi.org/10.3390/act13040140 - 10 Apr 2024
Viewed by 445
Abstract
Model Predictive Control (MPC) has many advantages in controlling an aero-engine, such as handling actuator constraints, but the computational burden greatly obstructs its application. The current multiplex MPC can reduce computational complexity, but it will significantly decrease the control performance. To guarantee real-time [...] Read more.
Model Predictive Control (MPC) has many advantages in controlling an aero-engine, such as handling actuator constraints, but the computational burden greatly obstructs its application. The current multiplex MPC can reduce computational complexity, but it will significantly decrease the control performance. To guarantee real-time performance and good control performance simultaneously, an intelligent reduced-dimensional scheme of MPC is proposed. The scheme includes a control variable selection algorithm and a control sequence coordination strategy. A constrained optimization problem with low computational complexity is first constructed by using only one control variable to define a reduced-dimensional control sequence. Therein, the control variable selection algorithm provides an intelligent mode to determine the control variable that has the best control effect at the current sampling instant. Furthermore, a coordination strategy is adopted in the reduced-dimensional control sequence to consider the interaction of control variables at different predicting instants. Finally, an intelligent reduced-dimensional MPC controller is designed and implemented on an aero-engine. Simulation results demonstrate the effectiveness of the intelligent reduced-dimensional scheme. Compared with the multiplex MPC, the intelligent reduced-dimensional MPC controller enhances the control quality significantly by 34.06%; compared with the standard MPC, the average time consumption is decreased by 64.72%. Full article
(This article belongs to the Special Issue Dynamics and Control of Aerospace Systems)
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15 pages, 4347 KiB  
Article
A Novel DC Electroosmotic Micromixer Based on Helical Vortices
by Sri Manikandan Saravanakumar, Mohsen Jamshidi Seresht, Ricardo Izquierdo and Paul-Vahe Cicek
Actuators 2024, 13(4), 139; https://doi.org/10.3390/act13040139 - 09 Apr 2024
Viewed by 421
Abstract
This work introduces a novel direct current electroosmosis (DCEO) micromixer designed for rapid and efficient fluid mixing. This micromixer demonstrates excellent capability, achieving approximately 98.5% mixing efficiency within a one-second timespan and 99.8% efficiency within two seconds, all within a simple channel of [...] Read more.
This work introduces a novel direct current electroosmosis (DCEO) micromixer designed for rapid and efficient fluid mixing. This micromixer demonstrates excellent capability, achieving approximately 98.5% mixing efficiency within a one-second timespan and 99.8% efficiency within two seconds, all within a simple channel of only 1000 µm in length. A distinctive feature of this micromixer is its ability to generate robust and stable helical vortices by applying a controlled DC electric field. Unlike complex, intricate microfluidic designs, this work proposes a simple yet effective approach to fluid mixing, making it a versatile tool suitable for various applications. In addition, through simple modifications to the driving signal configuration and channel geometry, the mixing efficiency can be further enhanced to 99.3% in one second. Full article
(This article belongs to the Special Issue Actuators in 2024)
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18 pages, 6690 KiB  
Article
Augmented Kalman Estimator and Equivalent Replacement Based Taylor Series-LQG Control for a Magnetorheological Semi-Active Suspension
by Juncheng Wang, Mingyao Zhou, Jiacheng Tong, Jinyu Liu and Shian Chen
Actuators 2024, 13(4), 138; https://doi.org/10.3390/act13040138 - 08 Apr 2024
Viewed by 453
Abstract
This research presents an augmented Kalman estimator and an equivalent replacement-based Taylor series (ERBTS)-linear quadratic Gaussian (LQG) control strategy to cope with the control accuracy and response delay of magnetorheological (MR) dampers for vehicle semi-active suspensions. The parameters in the MR model are [...] Read more.
This research presents an augmented Kalman estimator and an equivalent replacement-based Taylor series (ERBTS)-linear quadratic Gaussian (LQG) control strategy to cope with the control accuracy and response delay of magnetorheological (MR) dampers for vehicle semi-active suspensions. The parameters in the MR model are identified from experimental measurements. Then, two main sources of control error, namely, modelling error and real-time variety of the MR damper output force, are defined as an integrated compound real-time variety. Subsequently, they are written into a differential equation with characteristics of the minimum system to augment the state equation of the semi-active suspension system. The augmented Kalman estimator is constructed to estimate the abovementioned compound real-time variety. To calculate an acceptable time-delay compensation predictive control force, an equivalent operation is implemented beforehand in the suspension comprehensive performance index by replacing a part of the squared time-delay control force with the corresponding predictive control force. Simulation results verify the effectiveness of the proposed augmented Kalman estimator, and the newly developed ERBTS-LQG controller almost achieves control effectiveness of the ideal time delay free semi-active suspension. Full article
(This article belongs to the Special Issue Fault Detection and Isolation, Fault Tolerant Control for Autonomous and Transport Vehicles)
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18 pages, 5855 KiB  
Article
An Improved Zero-Flowrate Switching Control Method to Reduce Switching Losses in a Hydraulic Actuator
by Shuang Peng, Fanglong Yin and Yong Hu
Actuators 2024, 13(4), 137; https://doi.org/10.3390/act13040137 - 08 Apr 2024
Viewed by 374
Abstract
Hydraulic switching actuators are high-efficiency, fast response, and low-cost solutions for hydraulic control systems. One of the challenging problems is throttling losses during valve transitions. Previously, the authors proposed a zero-flowrate switching method to reduce the throttling energy loss of the switching valve, [...] Read more.
Hydraulic switching actuators are high-efficiency, fast response, and low-cost solutions for hydraulic control systems. One of the challenging problems is throttling losses during valve transitions. Previously, the authors proposed a zero-flowrate switching method to reduce the throttling energy loss of the switching valve, where a hydraulic resonator is applied to make the flowrates through the lines approaching zero before the valves are switched off. The major challenge of this approach is fast switching valves whose transition times are less than 2 ms. In this paper, an improved zero-flowrate switching method is presented. It utilizes the capacity with independent inlet/outlet ports to regulate flowrates through the lines. Models of capacity applied in a simple line with different pressure signals are developed to explore characteristics of the capacity, based on which a complete actuation system is developed. In the complete model, resistance and inductance are optimized to achieve the desired flowrate response. The improved zero-flowrate switching method reduces throttling energy losses by 99.945% compared to a hard switching system. The simulation results demonstrated that the improved zero-flowrate switching method performs as expected in the design condition. A capacity with proper volume is able to regulate flowrates through all the lines to zero, with the help of appropriate resistance and inductance. Compared to the previous zero-flowrate switching method, the novel strategy allows slower switching valves applied in hydraulic actuation systems and achieves better efficiency performance. This research paves a new avenue for reducing throttling energy losses and improves system efficiency in hydraulic switching actuators, as well as most of the hydraulic switch-mode circuits. Full article
(This article belongs to the Section Control Systems)
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14 pages, 977 KiB  
Article
Adaptive Quick Sliding Mode Reaching Law and Disturbance Observer for Robust PMSM Control Systems
by Hyeongki Ahn, Sangkyeum Kim, Jihoon Park, Yoonuh Chung, Mingyuan Hu and Kwanho You
Actuators 2024, 13(4), 136; https://doi.org/10.3390/act13040136 - 08 Apr 2024
Viewed by 411
Abstract
The permanent magnet synchronous motor (PMSM) has been of interest to eco-friendly industries on account of its advantages such as high performance, efficiency, and precision control. However, perturbations due to PMSM parameter uncertainty, load torque, and external disturbance interfere with the construction of [...] Read more.
The permanent magnet synchronous motor (PMSM) has been of interest to eco-friendly industries on account of its advantages such as high performance, efficiency, and precision control. However, perturbations due to PMSM parameter uncertainty, load torque, and external disturbance interfere with the construction of PMSM precision control systems. Therefore, a robust control system is needed to avoid unnecessary system movement caused by perturbations. In this paper, sliding mode control (SMC) is adopted to implement a robust control system for the PMSM. In order to reduce the reaching time from the initial system state to the sliding surface and the chattering phenomenon that can cause the system to malfunction, the adaptive quick sliding mode reaching law based on an exponential function and power equation is proposed. Although the SMC is robust to disturbance and parameter uncertainty, unexpected disturbances can destabilize the system. To estimate the unmatched disturbance in a short time, the second-order fast terminal sliding mode observer (SFTSMO) is proposed. The results show that the motor control system based on the proposed method has a fast convergence speed to an objective value, position tracking performance, and robustness. Full article
(This article belongs to the Special Issue Actuators in 2024)
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17 pages, 1770 KiB  
Article
A Wear Prediction Framework for Ball-Screw of Electro-Mechanical Brake Unit on Railway Trains
by Tianhe Ma, Jingjing Weng, Chun Tian and Mengling Wu
Actuators 2024, 13(4), 135; https://doi.org/10.3390/act13040135 - 08 Apr 2024
Viewed by 427
Abstract
The electro-mechanical brake is a new advancement in railway train braking. Ball-screws are important components of electro-mechanical braking units (EMBUs), and their wear can cause EMBUs to degrade in performance or even fail to function. In this paper, we present a framework for [...] Read more.
The electro-mechanical brake is a new advancement in railway train braking. Ball-screws are important components of electro-mechanical braking units (EMBUs), and their wear can cause EMBUs to degrade in performance or even fail to function. In this paper, we present a framework for prediction of ball-screw wear with discrete operating conditions as inputs, taking into account the time-varying characteristics of EMBUs. The framework includes determining the contact type, analyzing relative motion, calculating contact deformations, and estimating wear. The contact type is determined based on the quasi-static approach of Hertz theory. A dynamics model using multiple coordinate systems is established to analyze how balls and raceways move in relation to each other. The contact deformations of the ball–raceway contact are determined using numerical calculation. Then, the wear depth increment is calculated using the Archard model. The results of the calculation and the endurance test indicate that the wear on the screw raceway is greater than that on the nut raceway. The effect of velocity is greater than the effect of axial force. The presented calculation framework is reasonable and can be used for predicting EMBU ball-screw wear. Full article
(This article belongs to the Section Actuators for Land Transport)
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24 pages, 43488 KiB  
Article
Lateral Stability Control for Intelligent Commercial Vehicle Based on Reconstructed Objective Function Method
by Yafei Li, Yiyong Yang, Xiangyu Wang and Chengbiao Wang
Actuators 2024, 13(4), 134; https://doi.org/10.3390/act13040134 - 08 Apr 2024
Viewed by 403
Abstract
In this paper, a novel electric-hydraulic power steering (EHPS) system and a vehicle stability coordination control algorithm are proposed which can not only ensure the accuracy of the trajectory tracking but also solve the coordination control problem between the stability of the lateral [...] Read more.
In this paper, a novel electric-hydraulic power steering (EHPS) system and a vehicle stability coordination control algorithm are proposed which can not only ensure the accuracy of the trajectory tracking but also solve the coordination control problem between the stability of the lateral control and the stability of the roll in the extreme condition. Firstly, the EHPS system is designed to provide accurate control input of front wheel angle for vehicle lateral dynamics control. Secondly, on the basis of optimal preview theory, a new trajectory tracking fusion controller combined with sliding mode control is proposed to improve the accuracy and stability of the system in the process of vehicle lateral trajectory tracking control. Then, the stability domain boundary function of the phase plane is determined according to the phase plane of the sideslip angle-yaw rate, and the stability margin of the phase plane is calculated during the steering process. Finally, considering the tracking accuracy, lateral stability and roll stability performance in the process of trajectory tracking, the linear weighted algorithm is used to coordinate above three objectives, and the HIL bench test and real vehicle experiment verify that the proposed algorithm has good reliability and effectiveness. Full article
(This article belongs to the Special Issue Advanced Actuation and Control Technologies for Vehicle Driving Systems)
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22 pages, 31417 KiB  
Article
Two-Stage Predefined-Time Exact Sliding Mode Control Based on Predefined-Time Exact Disturbance Observer
by Bojun Liu, Wenle Ma, Zhanpeng Zhang and Yingmin Yi
Actuators 2024, 13(4), 133; https://doi.org/10.3390/act13040133 - 06 Apr 2024
Viewed by 400
Abstract
This paper is concerned with the predefined-time exact sliding mode control issue of a class of high-order uncertain nonlinear systems with disturbances. The proposed control scheme is composed of a predefined-time exact disturbance observer and a two-stage predefined-time exact sliding mode controller. The [...] Read more.
This paper is concerned with the predefined-time exact sliding mode control issue of a class of high-order uncertain nonlinear systems with disturbances. The proposed control scheme is composed of a predefined-time exact disturbance observer and a two-stage predefined-time exact sliding mode controller. The disturbance observer can estimate the system disturbances accurately within an arbitrary predefined observation time, and the time can be set as the handover time between two control stages. The classic sliding mode controller guarantees bounded system states in the first control stage. Then, a predefined-time sliding mode controller is designed based on time-varying tuning function, regulating the system states to exact zero within a final predefined settling time in the second stage. It is shown that the control input signal is always chattering-free with respect to time. The effectiveness and superiority of the proposed control scheme is demonstrated with simulation examples. Full article
(This article belongs to the Special Issue New Control Schemes for Actuators—2nd Edition)
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24 pages, 13343 KiB  
Article
Research on Mechanical Leg Structure Design and Control System of Lower Limb Exoskeleton Rehabilitation Robot Based on Magnetorheological Variable Stiffness and Damping Actuator
by Chenglong Zhao, Zhen Liu, Chongsong Zheng, Liucun Zhu and Yuefei Wang
Actuators 2024, 13(4), 132; https://doi.org/10.3390/act13040132 - 05 Apr 2024
Viewed by 468
Abstract
During the walking process of lower limb exoskeleton rehabilitation robots, inevitable collision impacts will occur when the swinging leg lands on the ground. The impact reaction force from the ground will induce vibrations in the entire robot’s body from bottom to top. To [...] Read more.
During the walking process of lower limb exoskeleton rehabilitation robots, inevitable collision impacts will occur when the swinging leg lands on the ground. The impact reaction force from the ground will induce vibrations in the entire robot’s body from bottom to top. To address this phenomenon, considering the limitations of traditional active compliance and passive compliance methods, a variable stiffness and damping actuator (VSDA) leg structure using a magnetorheological damper (MRD) is proposed. Firstly, experimental methods are used to obtain the ground reaction force (GRF) exerted on a normal person during walking. Then, a mathematical model of the VSDA leg structure is constructed, and its working principle is analyzed. Based on human mass and dimensions, a 3D model is designed and selected. Finally, a simulation model is built in the MATLAB/Simulink environment using the fuzzy switch damping control strategy to simulate the acceleration and displacement of the human body under sinusoidal and random excitations. The results indicate that under sinusoidal excitation, employing fuzzy switch damping control optimizes human displacement by 72.47% compared to the high stiffness and high damping system, and by 16.95% compared to the switch damping system. Human acceleration is optimized by 52.09% compared to the high stiffness and high damping system, and by 25.2% compared to the switch damping system. Under random excitation, adopting fuzzy switch damping control optimizes human displacement by 59.09% compared to the high stiffness and high damping system, and by 21.74% compared to the switch damping system. Human acceleration is optimized by 78.74% compared to the high stiffness and high damping system, and by 31.66% compared to the switch damping system. This validates the VSDA design structure and control method, demonstrating certain advantages in improving the compliance and stability of lower limb exoskeleton rehabilitation robots. Full article
(This article belongs to the Special Issue Soft Actuators for Medical Robotics)
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23 pages, 1782 KiB  
Article
Predefined Time and Accuracy Adaptive Fault-Tolerant Control for Nonlinear Systems with Multiple Faults
by Yakun Su, Yaling Jiang, Miao Tong and Huanqing Wang
Actuators 2024, 13(4), 131; https://doi.org/10.3390/act13040131 - 05 Apr 2024
Viewed by 452
Abstract
This work mainly studies the issue of predefined time and accuracy adaptive fault-tolerant control for strict-feedback nonlinear systems with multiple faults. The faults in the controlled system include actuator faults and external system faults. The unknown functions for nonlinear systems are approximated by [...] Read more.
This work mainly studies the issue of predefined time and accuracy adaptive fault-tolerant control for strict-feedback nonlinear systems with multiple faults. The faults in the controlled system include actuator faults and external system faults. The unknown functions for nonlinear systems are approximated by fuzzy logic systems (FLSs). And then, according to the backstepping technique and the predefined time stability theory, an adaptive fuzzy control algorithm is presented, which can make sure that all closed-loop system signals remain predefined time bound and the tracking error converges to a predefined accuracy within the predefined time. Ultimately, the effectiveness of the presented control algorithm is proved through two simulation examples. Full article
(This article belongs to the Special Issue Actuators in 2024)
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33 pages, 6190 KiB  
Article
Practical System Identification and Incremental Control Design for a Subscale Fixed-Wing Aircraft
by Rasmus Steffensen, Kilian Ginnell and Florian Holzapfel
Actuators 2024, 13(4), 130; https://doi.org/10.3390/act13040130 - 04 Apr 2024
Viewed by 445
Abstract
An incremental differential proportional integral (iDPI) control law using eigenstructure assignment gain design is tested in flight on a subscale platform to validate its suitability for fixed-wing flight control. A kinematic relation for the aerodynamic side-slip angle rate is developed to apply a [...] Read more.
An incremental differential proportional integral (iDPI) control law using eigenstructure assignment gain design is tested in flight on a subscale platform to validate its suitability for fixed-wing flight control. A kinematic relation for the aerodynamic side-slip angle rate is developed to apply a pseudo full state feedback. In order to perform the gain design and assessment, a plant model is estimated using flight test data from gyro, accelerometer, airspeed and surface deflection measurements during sine-sweep excitations. Transfer function models for the actuators and surface deflections are identified both in-flight and on the ground for several different actuators and control surfaces using hall sensor surface deflection measurements. The analysis reveals a large variation in bandwidth between the different types of servo motors. Flight test results are presented which demonstrates that the plant model estimates based on tests with good frequency excitation, high bandwidth actuators and surface deflection measurements can be used to reasonably predict the closed-loop dynamic behavior of the aircraft. The closed-loop flight test results of the iDPi control law show good performance and lays the groundwork for further development. Full article
(This article belongs to the Special Issue From Theory to Practice: Incremental Nonlinear Control)
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21 pages, 6425 KiB  
Article
In-Flight Calibration of Lorentz Actuators for Non-Contact Close-Proximity Formation Satellites with Cooperative Control
by He Liao, Mingxuan Song, Chenglin Weng and Daixin Wang
Actuators 2024, 13(4), 129; https://doi.org/10.3390/act13040129 - 03 Apr 2024
Viewed by 396
Abstract
The non-contact close-proximity formation satellite (NCCPFS) is one of the technical solutions to improve the attitude performance, consisting of a payload module (PM) and a support module (SM). The non-contact Lorentz actuator (NCLA), as the core components of the NCCPFS, directly affect the [...] Read more.
The non-contact close-proximity formation satellite (NCCPFS) is one of the technical solutions to improve the attitude performance, consisting of a payload module (PM) and a support module (SM). The non-contact Lorentz actuator (NCLA), as the core components of the NCCPFS, directly affect the attitude control performance of the entire satellite. In order to ensure the ultra-high attitude pointing performance and stability of the PM, an in-flight calibration method for the NCLAs based on minimum model error (MME) algorithm and Kalman filtering (KF) with cooperative control strategy is proposed in this article. In this method, the NCLAs generate a periodic nominal torque that causes the attitude of the PM to be periodically deflected. This periodic torque also reacts on the SM, and the SM counteracts this periodic torque through the flywheel to realize the cooperative tracking relative to the PM. Then, the gyroscope data are substituted into the MME algorithm to obtain the angular acceleration of the two modules, and the KF algorithm is adopted to observe the actual output torque of the NCLAs to complete the in-flight calibration of the NCLAs. Numerical simulation results show that the accuracy of the proposed calibration algorithm can reach about 8%, which proves the effectiveness of the proposed method. Full article
(This article belongs to the Section Aircraft Actuators)
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22 pages, 14173 KiB  
Article
Enhancing Damage Detection in 2D Concrete Plates: A Comprehensive Study on Interpolation Methods and Parameters
by Alaa Diab and Tamara Nestorović
Actuators 2024, 13(4), 128; https://doi.org/10.3390/act13040128 - 03 Apr 2024
Viewed by 395
Abstract
In an era marked by increasing demands for stability and durability in construction, the importance of damage detection in concrete structures cannot be overstated. As these structures underpin the safety and longevity of vital assets, this paper embarks on a comprehensive exploration of [...] Read more.
In an era marked by increasing demands for stability and durability in construction, the importance of damage detection in concrete structures cannot be overstated. As these structures underpin the safety and longevity of vital assets, this paper embarks on a comprehensive exploration of methodologies to enhance precision and reliability in 2D concrete plate damage detection. By focusing on the interpolation of damage index values and leveraging the insights gained from energy loss analysis and the characterization of the time of arrival of signals, we address the pressing need for improved non-destructive damage detection techniques. Our study encompasses a range of simulation attempts, each involving various interpolation parameters, and systematically evaluates their performance. The culmination of this research identifies the most effective combination of techniques and parameters, leading to the best results in damage detection. This multidimensional investigation promises to provide valuable contributions to the field of structural health monitoring, benefiting both researchers and practitioners engaged in the evaluation of concrete structures. Full article
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16 pages, 16001 KiB  
Article
On Combining Shape Memory Alloy Actuators and Pneumatic Actuators for Performance Enhancement in Soft Robotics
by Florian-Alexandru Brașoveanu and Adrian Burlacu
Actuators 2024, 13(4), 127; https://doi.org/10.3390/act13040127 - 03 Apr 2024
Viewed by 409
Abstract
Through soft robotics, flexible structures confer an elevated degree of protection and safety in usage, as well as precision and reliability. Using theoretical models while combining different types of soft components opens a wide variety of possibilities for the development of new and [...] Read more.
Through soft robotics, flexible structures confer an elevated degree of protection and safety in usage, as well as precision and reliability. Using theoretical models while combining different types of soft components opens a wide variety of possibilities for the development of new and better alternatives to rigid robots. Modeling and controlling soft robotic structures is still a challenge and is presented in different ways by the scientific community. The present scientific work aims to combine two of the most popular types of soft actuators, specifically shape memory alloy and pneumatic actuators. The purpose is to observe the interaction between individual entities and the resulting combined dynamics, highlighting the distinctive effects and influences observed in the combined system. An evaluation is conducted from a numerical simulation perspective in the MATLAB environment using representative mathematical models. The tests prove that a structure combining these particular actuators benefits from the advantages of both components and even compensates for individual downsides. Full article
(This article belongs to the Special Issue Advanced Robots: Design, Control and Application—2nd Edition)
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