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We propose a new type of soft actuator based on carbon nanotube (CNT) composite paper (CNTCP), i.e., a paper actuator. In our previous study, we demonstrated that actuator operation was possible when using CNTCPs as electrodes with ordinary paper containing ionic liquid between the electrodes; however, their bending motion was not sufficient. Therefore, we here attempt to modify the paper actuator. For this, we tried to soften CNTCPs by first reducing the ratio of contained CNTs. In addition, as a new strategy, we took advantage of the fact that the proposed actuator was made of paper and introduced the Kirigami (introducing periodical slits to papers) technique into the structure of our paper actuator. As a result, the performance of the actuator was improved, and its bending motion became visibly larger. The response of the improved actuator to the input voltage was investigated in detail, and the detailed operating conditions could be clarified. Moreover, it was found that not only a bending motion but also a twisting motion could be realized in specific slit patterns. It is thought that the fact that the variation in movement can be increased simply by adding incisions is unique to the proposed paper actuator. [ABSTRACT FROM AUTHOR]

The deterioration of large steel structures, such as bridges and power generation facilities built in the 1960s, has become a problem. Such infrastructure requires regular inspections every few years, and many robots have been proposed for structural inspection. However, inspection technology for large steel structures by robots has not yet been established. The establishment of inspection technology in bridges is one of the most important issues in the maintenance of social infrastructure. This paper proposes a novel vibration actuator as a new robot drive source, which combines mechanical resonance and electromagnetic force and enables reciprocating movement by orthogonally arranging multiple vibration components. By controlling the phase difference of these vibration components with only a simple signal generator and amplifier, machine tests showed that reciprocating and rotating reciprocating motions with almost the same characteristics are possible. Experimental results reveal that the vibration actuator is able to pull a load mass of 150 g. In addition, motion analysis is conducted by applying the energy method and considering the effects of phase control on the linear and rotational motions of the vibration actuator. The results obtained in the machine test and the analysis results are mostly in agreement. This confirms that even if the parameters for the vibration actuator are varied, the linear and rotational characteristics of the actuator can be predicted by theoretical calculations. A new drive source for robots and the operation of electromagnetic motors capable of linear and rotational motion are established in this paper. For this reason, the possibility of realizing social infrastructure improvement for large steel structures such as bridges is demonstrated. [ABSTRACT FROM AUTHOR]

Enhancing the transparency of high-transmission-ratio linear actuators is crucial for improving the safety and capability of high-force robotic systems having physical contact with humans in unstructured environments. However, realizing such enhancement is challenging. A proposed solution for active body weight support systems involves employing a macro–mini linear actuator incorporating an electrorheological-fluid brake to connect a high-force unit with an agile, highly back-drivable unit. This paper introduces the use of an electromagnetic (EM) brake with reduced rotor inertia to address this challenge. The increased torque capacity of the EM brake enables integration with a low-gear-ratio linear transmission. The agile translation of the endpoint is propelled by a low-inertia motor (referred to as the "mini") via a pulley-belt mechanism to achieve high transparency. The rotor of the EM brake is linked to the pulley. Damping modulation under high driving force is achieved through the adjustment of the brake torque relative to the rotational speed of the pulley. When the brake is engaged, it prevents any relative motion between the endpoint and the moving carrier. The endpoint is fully controlled by the ball screw of the high-force unit, referred to as the "macro". A scaled prototype was constructed to experimentally characterize the damping force generated by the mini motor and the EM brake. The macro–mini linear actuator, equipped with an intrinsic failsafe feature, can be utilized for active body weight support systems that demand high antigravity force. [ABSTRACT FROM AUTHOR]

Cyber–physical testing has been applied for a decade in hydrodynamic laboratories to assess the dynamic performance of floating wind turbines (FWTs) in realistic wind and wave conditions. Aerodynamic loads, computed by a numerical simulator fed with model test measurements, are applied in real time on the physical model using actuators. The present paper proposes a set of short and targeted benchmark tests that aim to quantify the performance of actuators used in cyber–physical FWT testing. They aim at ensuring good load tracking over all frequencies of interest and satisfactory disturbance rejection for large motions to provide a realistic test setup. These benchmark tests are exemplified on two radically different 15 MW FWT models tested at SINTEF Ocean using a cable-driven robot. [ABSTRACT FROM AUTHOR]

Piezoelectric (PZT) stack actuators are widely used in many fields due to the advantages such as small stroke and high force output. However, failures of one or more PZT layers may exist in PZT stacks and then have influences on their performances. This paper investigates dynamic responses of normal and partially failed PZT stack actuators, in order to evaluate the influences of a failed layer at different positions and furthermore explore the rules, which is of great significance for understanding and improving the performances of partially failed PZT stack actuators. Firstly, a group of experiments were performed and responses of PZT stacks were obtained under sinusoidal voltages with DC biasing. Then a multiple degree-of-freedom (DOF) spring-mass system was built as a theoretical model which was verified by the experimental results to simulate output responses of PZT stack actuators. Based on that, the influences of a failed PZT layer at different positions in the stack were obtained by solving the model under various conditions. The results reveal that the farther the failed PZT layer is from the fixed end, the more significant the influences on the displacement or force output of the PZT stack are. Moreover, the rules of influences of a failed PZT layer at different positions were expressed as a general formula which can be used to better understand, evaluate or identify health conditions of PZT stack actuators. [ABSTRACT FROM AUTHOR]

The paper proposes a novel automatic control system for the attitude of the mini-satellites equipped with an actuator having N = 2 DGMSCMGs (Double Gimbal Magnetically Suspended Control Moment Gyros) in parallel and orthogonal configuration, as well as a DGMSCMG-type sensor for the measurement of the satellite absolute angular rate. The proportional-derivative controller, designed based on the Lyapunov-functions theory, elaborates the control law according to which the angular rates applied to the servo systems for the actuation of the DGMSCMGs gyroscopic gimbals are computed. The gimbal's angular rates create gyroscopic couples acting on the satellite in order to control its attitude with respect to the local orbital frame. The new proposed control architecture was software implemented and validated, and the analysis of the obtained results proved the cancellation of the convergence errors and excellent angular rate precision. [ABSTRACT FROM AUTHOR]

This review paper discusses the development trends of agricultural autonomous all-terrain vehicles (AATVs) from four cornerstones, such as (1) control strategy and algorithms, (2) sensors, (3) data communication tools and systems, and (4) controllers and actuators, based on 221 papers published in peer-reviewed journals for 1960–2023. The paper highlights a comparative analysis of commonly employed control methods and algorithms by highlighting their advantages and disadvantages. It gives comparative analyses of sensors, data communication tools, actuators, and hardware-embedded controllers. In recent years, many novel developments in AATVs have been made due to advancements in wireless and remote communication, high-speed data processors, sensors, computer vision, and broader applications of AI tools. Technical advancements in fully autonomous control of AATVs remain limited, requiring research into accurate estimation of terrain mechanics, identifying uncertainties, and making fast and accurate decisions, as well as utilizing wireless communication and edge cloud computing. Furthermore, most of the developments are at the research level and have many practical limitations due to terrain and weather conditions. [ABSTRACT FROM AUTHOR]

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The crank-type vibration exciters represent innovative and promising actuators for a variety of vibratory technological equipment. Extensive research has demonstrated their potential for generating specific trajectories of the working components of various technological machines. This study builds upon previous investigations of the authors, focusing on the kinematics and dynamics of crank-type vibration exciters, with a specific emphasis on analyzing the forces, moments, and torques acting on the elements of the twin crank-type actuating mechanism. The research methodology involves the development of a simplified dynamic diagram of the mechanism and derivation of the analytical expressions to describe its force parameters. Mathematical modeling and computer simulation are then conducted to analyze the forces, moments, and torques experienced by the mechanism during its motion under different operational conditions and design parameters. The results obtained provide time-dependent profiles of these parameters across various conditions and design configurations of the twin crank-type mechanism. A key scientific contribution of this paper consists in the development of the theoretical basis for creating novel techniques of dynamic and strength analysis and optimization of design and operational parameters of enhanced vibration exciters equipped with twin crank-type mechanisms. The research findings offer valuable insights for engineers involved in the development and enhancement of vibratory technological machines equipped with crank-type vibration exciters. [ABSTRACT FROM AUTHOR]

Recently, antiferroelectric and antiferroelectric‐like materials have regained interest in electronic devices, such as field‐effect transistors, memory, and transducers. Particularly in micro/nano‐electromechanical coupling systems such as actuators, these innovative materials, with their peculiar phase transition between antiferroelectric and ferroelectric phases, show promise in offering large electro‐strain, fast response, and low power consumption devices. However, compared to numerous computational models of ferroelectric actuators, numerical modeling of antiferroelectric and antiferroelectric‐like actuators remains relatively unexplored. In this paper, we propose a phenomenological model of uniaxial antiferroelectric and antiferroelectric‐like actuators based on their switching polarization behavior. Specifically, both the double hysteresis loop of antiferroelectric materials and the pinched hysteresis loop of antiferroelectric‐like materials can be captured by two hyperbolic tangent functions. This allows us to cast a polarization‐dependent strain and piezoelectric tensor into the constitutive laws. The proposed model is then implemented into a finite element framework, in which the voltage‐induced deformation can be solved using the Newton–Raphson procedure. Numerical examples of both antiferroelectric and antiferroelectric‐like actuators are illustrated and compared with experimental data, showing our proposed model can serve as a useful tool for the design and development of antiferroelectric and antiferroelectric‐like actuators. [ABSTRACT FROM AUTHOR]

In machine hammer peening, an actuator system moves a ram in oscillating motion, which is oriented in angular position, preferably perpendicular, to a workpiece surface. On the tip of the ram, a hammer head with application specific shapes can be mounted. The hammer head is moved across the targeted workpiece surface area by means of a machine tool or an industrial robot. The impacts in defined patterns enable modifications of the surface integrity like smoothing the surface roughness or increasing fatigue strength by induced compressive residual stresses. This paper presents a novel DC-driven actuator system using a highly dynamic short-stroke linear reluctance motor to provide a time or trigger controlled hammer head movement including a system for process monitoring. In contrast to conventional systems, Deterministic Impact Peening (DIP) can be realized by position or speed related triggering of the impacts. The reluctance-based actuator with its geometrically optimized mechatronic system design provides performance characteristics favorable to known machine hammer peening systems. The position-controlled triggering of the hammer head is able to achieve uniform or defined local elastoplastic deformations on the workpiece surface, thus resulting in deterministic residual stress distributions. [ABSTRACT FROM AUTHOR]

Crawling is a rhythmic locomotor behavior of animals, and its underlying mechanisms has been studied by many scholars for over a hundred years. With the continuous progress of computer integration technology, materials science, aerodynamics, micro-nano manufacturing, and artificial intelligence technology, the research on bionic crawling robots is developing towards miniaturization and intelligence. This paper provides a comprehensive review on the cutting-edge dynamic development of insect level micro crawling robots, and provides constructive suggestions for the future development of micro crawling robots based on the current development trend. First, the research background and basic concepts of micro crawling robots are introduced, and the motion mechanism and stability criteria of micro crawling robots are briefly analyzed. Second, the driving methods of micro crawling robots are analyzed and the performance of various micro crawling robots is compared. Finally, the key technologies of micro crawling robots are summarized from three aspects: Energy supply, manufacturing, and design. The problems faced in the research of micro crawling robots are discussed, and the future application prospects and development directions of micro crawling robots are proposed. [ABSTRACT FROM AUTHOR]

A variety of parameters influence the performance of piezoelectric sensors and actuators, such as support and concentrated mass. This paper presents a finite element formulation for piezoelectric structures and studies the effect of parameters on them. This method was developed based on the Bernoulli-Euler beam and the model is considered for use as a beam structure using the Variation Principle. The model was used for static and vibration analysis. The effects of support on the deflection of the piezoelectric beam were studied. Modal analysis was also carried out for the electromechanical coupling and uncoupling beams, and the effect of the concentrated mass was deduced. The finite element model was developed with FORTRAN programming Language and was implemented with MATLAB software. A comparison of the results between the analytical method, engineering software, and this program, showed acceptable accuracy. [ABSTRACT FROM AUTHOR]

Poly(ionic liquid) (PIL)‐based porous membranes are extensively investigated as soft polymer actuators. While PILs have shown significant advancements in membrane fabrication and stabilization of metal nanoparticles (MNPs), research on integrating MNPs into porous membranes to achieve actuation behavior under multiple stimuli is limited. Herein, this work presents a new paradigm for designing a porous PIL‐polyacrylic acid (PAA) membrane with a distinct MNP gradient via a top‐bottom diffusion approach involving a metal salt precursor solution and NaBH4 as a reducing agent. The strong binding sites provided by PILs, combined with the gradient distribution of ‐COO− groups across the membrane cross‐section, play a significant role in controlling the MNPs' gradient distribution. Interestingly, the MNPs within the membrane display excellent catalytic activity in exothermic reactions such as H2O2 decomposition, dissipating uneven heat that quickly permeates the membrane network. This induces asymmetrical swelling of polymer chains, resulting in rapid membrane bending. Furthermore, such MNP‐loaded membrane could serve as a portable test paper for visually monitoring H2O2. This advancement paves the way for the development of intricate smart actuation materials and expands their practical applications in various real‐life scenarios. [ABSTRACT FROM AUTHOR]

It is the responsibility of every individual to ensure the cleanliness and sustainability of the environment. We have created a waste management model that utilizes various sensors such as soil moisture sensors, ultrasonic sensors, and inductive proximity sensors, along with a conveyor belt, to automate the process of waste segregation. The ultrasonic sensor is used to detect dry waste based on its distance from the sensor, while the soil moisture sensor is employed to identify wet waste by measuring the moisture content in the waste. The inductive proximity sensor plays a crucial role in identifying metal waste by detecting any metallic objects present in the waste stream. The entire system is designed to streamline the waste separation process, thereby minimizing the need for manual sorting and enhancing overall efficiency. By integrating these sensors with the conveyor belt mechanism, the system enables real-time waste detection and segregation, thereby optimizing waste management operations. The proposed intelligent waste management system offers numerous advantages, including enhanced precision in waste categorization, reduced human errors, increased efficiency in waste collection, and the potential for recycling and resource recovery. [ABSTRACT FROM AUTHOR]

This paper proposes an improved actuator system model for UAV elevators using multibody dynamics simulation. The multibody dynamics simulation employs the Simscape Multibody, module in MATLAB coupled with Simulink to model the servo and hinge moment calculation. The actuator system comprises an electrical servo and mechanical components, including arms, push rods, horns, and the elevator. The electrical servo is modeled using a PID controller and a simplified motor model. The multibody dynamics simulation is employed to capture the dynamics of the mechanical components, coupled with the electrical servo through torque delivery to the mechanical components. The simulation is applied to the elevator of a medium altitude long endurance (MALE) UAV with a Maximum Take Off Weight of 1300 Kg. Generating these quantities provide a benefit in capturing the operational envelope of the servo to be compared to its limitations. Given the features of this simulation, it is proposed to extend the research by integrating this method with flight dynamics simulation. [ABSTRACT FROM AUTHOR]

Shape memory alloy (SMA) actuators are widely used in various actuators due to their advantages of simplicity, high strength, and flexibility. The mapping relationship between the resistance change and displacement during the phase transition process of SMA enables its self-sensing control without external displacement sensors. However, the limited accuracy and high complexity of existing self-sensing models are two crucial factors restricting the wide application of self-sensing control. Due to the high nonlinearity of the SMA wire's phase transition process, it is challenging to achieve accurate position estimation using a simple self-sensing model. Thus, this paper proposes a novel approach by utilizing the simplest linear model for position estimation. The inevitable modeling errors are directly compensated in the final control results, rather than compensating for estimation errors. This significantly reduces the implementation difficulty of SMA self-sensing control and effectively improves control accuracy. Furthermore, a highly integrated prototype of SMA actuator is designed in this paper, where the additional position sensor and self-resetting loading device are integrated, greatly reducing the size of the SMA actuator. A series of self-sensing tracking experiments are conducted on this prototype, validating that the compensated self-sensing control can achieve comparable performance to the control method with external sensors. [Display omitted] • A novel highly integrated prototype of an SMA actuator is designed. • A simple linear self-sensing model is constructed to realize closed-loop control. • A zero-phase error compensation scheme is proposed to improve tracking accuracy. [ABSTRACT FROM AUTHOR]

This review paper discusses the development trends of agricultural autonomous all-terrain vehicles (AATVs) from four cornerstones, such as (1) control strategy and algorithms, (2) sensors, (3) data communication tools and systems, and (4) controllers and actuators, based on 221 papers published in peer-reviewed journals for 1960–2023. The paper highlights a comparative analysis of commonly employed control methods and algorithms by highlighting their advantages and disadvantages. It gives comparative analyses of sensors, data communication tools, actuators, and hardware-embedded controllers. In recent years, many novel developments in AATVs have been made due to advancements in wireless and remote communication, high-speed data processors, sensors, computer vision, and broader applications of AI tools. Technical advancements in fully autonomous control of AATVs remain limited, requiring research into accurate estimation of terrain mechanics, identifying uncertainties, and making fast and accurate decisions, as well as utilizing wireless communication and edge cloud computing. Furthermore, most of the developments are at the research level and have many practical limitations due to terrain and weather conditions.

This paper presents the design, analysis, and development of a dexterous hand driven by TCP actuators, termed the SoroAgilHand-1. Using the elastic stress of the TCP array with the measured Young's modulus, a mapping model of the tendon-contracted length to the joint angle of the dexterous hand was developed and validated by the recorded trajectory of the thumb-index finger. We introduced a self-sensing model for the TCP array in the SoroAgilHand-1 system and established an integrated closed-loop control system using the tensile sensors and strain-measuring devices. Considering the Kapandji test and the Feix taxonomy, the grasping performance of SoroAgilHand-1 was evaluated using postures from the collected data. The experimental results show that the soft dexterous hand can achieve 33 grasping postures and pass the Kapandji test, implying that it fulfils the anthropomorphic design goal using TCP actuators. Moreover, based on the grabbing stability test from the Feix taxonomy, the finger-tip trajectory of the closed-loop controller for the driven TCP was significantly improved and exhibited greater stability than that in open-loop driving. [Display omitted] • Twisted and coiled polymer actuators are applied in the dexterous hand robot. • The self-sensing controller for TCP is applied by measured tensile and strain. • The trajectory of robot fingers is improved by self-sensing control for TCP. • Posture-test are conducted on the robot based on the Kapandji and Feix taxonomy [ABSTRACT FROM AUTHOR]

[Display omitted] • A 3D numerical study was conducted on a micromixer with an oscillating microbeam. • Effects of oscillation frequency and Reynolds number on mixing were investigated. • The optimum operating condition was found for this micromixer. • Four novel designs were proposed by adding passive techniques to this micromixer. • The maximum mixing index was 88% in 0.4 s. In this research, we numerically studied a three-dimensional (3-D) T-shaped active micromixer which works based on the oscillations of a cantilever microbeam. We explored the influence of microbeam's oscillation frequency (10–40 Hz) and flow Reynolds number (2.5–30) on mixing performance, revealing optimal operating conditions. Under optimal operating conditions, using a simple microbeam in a short straight microchannel, the micromixer achieved a 76.7 % mixing index within just 0.4 s. In the next part of this paper, we introduced modifications to the microbeam and microchannel geometries to enhance mixing performance further. Adding a circular part to the channel improved the mixing index to 85.7 %. In a more complex configuration, characterized by a perforated microbeam and a circular microchannel, the micromixer achieved its highest efficiency of 88 %. Additionally, a novel configuration employing two microbeams within a straight channel achieved a mixing efficiency of 82.2 %. [ABSTRACT FROM AUTHOR]

Actuators based on shape memory polymers and composites incorporating nanomaterial additives have been extensively studied; achieving both high output stress and precise shape change by low‐cost, scalable methods is a long‐term‐desired yet challenging task. Here, conventional polymers (polyurea) and carbon nanotube (CNT) fillers are combined to fabricate reinforced composite fibers with exceptional actuation performance, by a wet‐spinning method amenable for continuous production. It is found that a thermal‐induced shrinkage step could obtain densified strong fibers, and the presence of CNTs effectively promotes the tensile orientation of polymer molecular chains, leading to much improved mechanical properties. Consequently, the CNT/ polyurea composite fibers exhibit stresses as high as 33 MPa within 0.36 s during thermal actuation, and stresses up to 22 MPa upon electrical stimulation enabled by the built‐in conductive CNT networks. Utilizing the flexible thin fibers, various shape change behavior are also demonstrated including the conversion between different structures/curvatures, and recovery of predefined simple patterns. This high‐performance composite fibers, capable of both thermal and electrical actuation and produced by low‐cost materials and fabrication process, may find many potential applications in wearable devices, robotics, and biomedical areas. [ABSTRACT FROM AUTHOR]

The increasing demand for innovative grippers and actuators for the automation sector encourages the development of new and innovative functional principles. Intelligent materials are particularly suitable for this purpose based on their high energy density. In this study, a two-finger gripper driven by shape memory alloys (SMA) for use in automation technology is presented. Previous grippers driven by SMA can only be found in the field of micro gripping due to the limited stroke generated by SMA. Based on a methodical product development, a new type of gripper was developed and is presented in this study, which can achieve an opening width comparable to conventional grippers based on transmission mechanisms. Two different variants of the gripper are shown and compared aiming to minimize the installation space and weight of the gripper. In addition to the design presentation, a prototype is built, and the functionality is demonstrated through various test series. [ABSTRACT FROM AUTHOR]

Actuators based on moisture-sorption-responsive materials can convert moisture energy into mechanical/electrical energy, making the development of moisture-sorption materials a promising pathway for harnessing green energy to address the ongoing global energy crisis. The deformability of these materials plays a crucial role in the overall energy conversion performance, where moisture sorption capacity determines the energy density. Efforts to boost the moisture absorption capacity and rate have led to the development of a variety of moisture-responsive materials in recent years. These materials interact with water molecules in different manners and have shown diverse application scenarios. Here, in this review, we summarize the recent progress on moisture-sorption-responsive materials and their applications. We begin by categorizing moisture-sorption materials—biomaterials, polymers, nanomaterials, and crystalline materials—according to their interaction modes with water. We then review the correlation between moisture-sorption and energy harvesting performance. Afterwards, we provide examples of the typical applications using these moisture-sorption materials. Finally, we explore future research directions aimed at developing next-generation high-performance moisture-sorption materials with higher water uptake, tunable water affinity, and faster water absorption. [ABSTRACT FROM AUTHOR]

Developing hydroscopic actuators with simultaneous high elasticity, shape programmability and tunable actuating behaviors are highly desired but still challenging. In this study, we propose an orthogonal composite design to develop such a material. The developed composite elastomer comprises carboxyl group-grafted polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene (SEBS-g-COOH) as the elastic substrate, and a synthesized azobenzene derivative as the functional filler (Azo12). By surface treatment using acidic and base solutions, the carboxyl groups on the surface can reversibly transform into carboxylate groups, which render the composite tunable hygroscopic actuating functionality. On another aspect, the added filler undergoes trans-to-cis isomerization when exposed to UV light irradiation, leading to liquefaction of the crystalline aggregates formed by Azo12 molecules. The liquefied Azo12 molecules can autonomously resotre their trans form and reform the crystalline structure. This reversible change in crystralline structure is utilized to realize the shape memory property, and 5 wt% of Azo12 addition is adequate for the composite to exhibit photo-responsive shape memory behavior without compromising much of the elasricity. The regualtion of external geometry by shape memory effect is effective in altering the actuating behavior. The proposed method can be extend to designing different composites with the demonstrated functionalities. [ABSTRACT FROM AUTHOR]

Owing to their physical and chemical properties and stimuli-responsive nature, gels and hydrogels play vital roles in diverse application fields. The three-dimensional polymeric network structure of hydrogels is considered an alternative to many materials, such as conductors, ordinary films, constituent components of machines and robots, etc. The most recent applications of gels are in different devices like sensors, actuators, flexible screens, touch panels, flexible storage, solar cells, batteries, and electronic skin. This review article addresses the devices where gels are used, the progress of research, the working mechanisms of hydrogels in those devices, and future prospects. Preparation methods are also important for obtaining a suitable hydrogel. This review discusses different methods of hydrogel preparation from the respective raw materials. Moreover, the mechanism by which gels act as a part of electronic devices is described. [ABSTRACT FROM AUTHOR]

Precision research and technological equipment, as a rule, is not able to provide its specification characteristics without a high-quality vibration protection system. Active vibration control of an object is provided with the help of an additional source of movement, an actuator. The most promising high accuracy actuators are based on smart materials, such as materials with shape memory, piezoelectric and magnetostrictive materials, electro- and magnetic active fluids and elastomers. Dielectric elastomer is one of the types of electroactive polymers. Actuators based on a dielectric elastomer show high performance in terms of accuracy and speed and operate due to the controllable deformation of the elastomer under the action of a high voltage electric field. The paper provides a comparison of actuators based on sheet and thin film control electrodes. The influence of the quality of the polymer surface and the type of electrodes on the travel range of the actuator and maximum amplitude of vibrations the system can suppress on the basis of a dielectric elastomer is estimated. The formation of the electrode by magnetron sputtering in vacuum makes it possible to create a thin-film layer of copper that covers the elastomer, despite the developed surface. The effect of ion treatment of an elastomer before coating on the quality of the formed electrode is considered. After the ion treatment, the surface of the elastomer acquires a more uniform regular structure. A thin-film electrode layer is formed according to the topology of the elastomer to an accomplished standard.

A variety of parameters influence the performance of piezoelectric sensors and actuators, such as support and concentrated mass. This paper presents a finite element formulation for piezoelectric structures and studies the effect of parameters on them. This method was developed based on the Bernoulli-Euler beam and the model is considered for use as a beam structure using the Variation Principle. The model was used for static and vibration analysis. The effects of support on the deflection of the piezoelectric beam were studied. Modal analysis was also carried out for the electromechanical coupling and uncoupling beams, and the effect of the concentrated mass was deduced. The finite element model was developed with FORTRAN programming Language and was implemented with MATLAB software. A comparison of the results between the analytical method, engineering software, and this program, showed acceptable accuracy.

The paper presents the design of a damper based on a multilayer magnetorheological elastomer that has high load capacity, up to 500 N. The damper is able to operate in all vibration control modes, depending on its control signal. The damper cooling system is presented. Vibration tests were carried out and the damper amplitude-frequency characteristics were obtained. The transition process of damper displacement with a control step signal was analyzed.

The development of fast-responding electrically conductive polymers as actuators activated by low electrical current is now regarded as an urgent matter. Due to their limited electrical conductivity, actuators based on polymeric hydrogels must be activated using a high voltage (up to 200 V) and frequency (up to 500 Hz) when employing AC power. In this work, to improve the electrical conductivity of the hydrogel and decrease the required activation voltage of the hydrogel actuators, lithium chloride (LiCL) was added as a conductive filler to the polymer matrix of polyvinyl alcohol (PVA). In order to ascertain the deformation of actuators, activation and relaxation times, actuator efficiencies, and generated force under the conditions of activation, linear actuators that can be activated by extension/contraction (swelling/shrinking) cycles were prepared and investigated depending on the LiCl content, applied voltage, and frequency. Under a load of approximately 20 kPa and using a 90 V AC power at a 50 Hz frequency with a 30 wt.% LiCl content, it was found that the actuators' total contraction, reinforced by a woven mesh braided material, was about 20% with a ~2.2 s activation time, while the actuators' total extension, reinforced by a spiral weave material, was about 52% with a ~2.5 s activation time, after applying a 110 V AC at a 50 Hz frequency with a 10 wt.% LiCl content. Furthermore, as the lowest voltage, a 20 V AC power can operate these actuators by increasing the LiCl weight content to the same PVA mass content. Moreover, the PVA/LiCl hydrogels' activation force can be greater than 0.5 MPa. The actuators that have been developed have broad applications in soft robotics, artificial muscles, medicine, and aerospace fields. [ABSTRACT FROM AUTHOR]

AISI 440C is a high carbon martensitic stainless steel with superior wear and abrasion resistance among all grades of stainless steel. Hydraulic amplifier valve (HAV) spools, made of AISI 440C stainless steel, are used in flow control devices of launch vehicle actuator systems. In the present case, a failure occurred near the undercut region of the HAV spool during the vibration test. The failure was observed specifically at M5 threaded region of the spool. A detailed investigation has been carried out to understand the root cause of the failure. 612 µm deep pit was observed with corrosion products on the fracture surface near to the undercut region of M5 thread. Elemental chemical composition analysis via energy-dispersive X-ray spectroscopy (EDS) confirmed the presence of oxygen and chlorine in the pit location. Primary carbides exposed to the rough machined surface at the undercut region lead to the pit initiation and propagation because of the galvanic potential difference between matrix and primary carbides. Failure of the HAV spool is attributed to corrosion-assisted overload. [ABSTRACT FROM AUTHOR]

To meet the requirements of amphibious exploration, ocean exploration, and military reconnaissance tasks, a pneumatic amphibious soft bionic robot was developed by taking advantage of the structural characteristics, motion forms, and propulsion mechanisms of the sea lion fore-flippers, inchworms, Carangidae tails, and dolphin tails. Using silicone rubber as the main material of the robot, combined with the driving mechanism of the pneumatic soft bionic actuator, and based on the theory of mechanism design, a systematic structural design of the pneumatic amphibious soft bionic robot was carried out from the aspects of flippers, tail, head–neck, and trunk. Then, a numerical simulation algorithm was used to analyze the main executing mechanisms and their coordinated motion performance of the soft bionic robot and to verify the rationality and feasibility of the robot structure design and motion forms. With the use of rapid prototyping technology to complete the construction of the robot prototype body, based on the motion amplitude, frequency, and phase of the bionic prototype, the main execution mechanisms of the robot were controlled through a pneumatic system to carry out experimental testing. The results show that the performance of the robot is consistent with the original design and numerical simulation predictions, and it can achieve certain maneuverability, flexibility, and environmental adaptability. The significance of this work is the development of a pneumatic soft bionic robot suitable for amphibious environments, which provides a new idea for the bionic design and application of pneumatic soft robots. [ABSTRACT FROM AUTHOR]

This paper proposes an improved actuator system model for UAV elevators using multibody dynamics simulation. The multibody dynamics simulation employs the Simscape Multibody, module in MATLAB coupled with Simulink to model the servo and hinge moment calculation. The actuator system comprises an electrical servo and mechanical components, including arms, push rods, horns, and the elevator. The electrical servo is modeled using a PID controller and a simplified motor model. The multibody dynamics simulation is employed to capture the dynamics of the mechanical components, coupled with the electrical servo through torque delivery to the mechanical components. The simulation is applied to the elevator of a medium altitude long endurance (MALE) UAV with a Maximum Take Off Weight of 1300 Kg. Generating these quantities provide a benefit in capturing the operational envelope of the servo to be compared to its limitations. Given the features of this simulation, it is proposed to extend the research by integrating this method with flight dynamics simulation.

Shape-shifting polymers are widely used in various fields such as intelligent switches, soft robots and sensors, which require both multiple stimulus-response functions and qualified mechanical strength. In this study, a novel near-infrared-light (NIR)-responsible shape-shifting hydrogel system was designed and fabricated through embedding vinylsilane-modified carbon nanotubes (CNTs) into particle double-network (P-DN) hydrogels by micellar copolymerisation. The dispersed brittle Poly(sodium 2-acrylamido-2-methylpropane-1-sulfonate) (PNaAMPS) network of the microgels can serve as sacrificial bonds to toughen the hydrogels, and the CNTs endow it with NIR photothermal conversion ability. The results show that the CNTs embedded in the P-DN hydrogels present excellent mechanical strength, i.e., a fracture strength of 312 kPa and a fracture strain of 357%. Moreover, an asymmetric bilayer hydrogel, where the active layer contains CNTs, can achieve 0°–110° bending deformation within 10 min under NIR irradiation and can realise complex deformation movement. This study provides a theoretical and experimental basis for the design and manufacture of photoresponsive soft actuators. [ABSTRACT FROM AUTHOR]

Wearable mechatronics for powered orthoses, exoskeletons and prostheses require improved soft actuation systems acting as 'artificial muscles' that are capable of large strains, high stresses, fast response and self-sensing and that show electrically safe operation, low specific weight and large compliance. Among the diversity of soft actuation technologies under investigation, pneumatic devices have been the focus, during the last couple of decades, of renewed interest as an intrinsically soft artificial muscle technology, due to technological advances stimulated by applications in soft robotics. As of today, quite a few solutions are available to endow a pneumatic soft device with linear actuation and self-sensing ability, while also easily achieving these features with off-the-shelf materials and low-cost fabrication processes. Here, we describe a simple process to make self-sensing pneumatic actuators, which may be used as 'inverse artificial muscles', as, upon pressurisation, they elongate instead of contracting. They are made of an elastomeric tube surrounded by a plastic coil, which constrains radial expansions. As a novelty relative to the state of the art, the self-sensing ability was obtained with a piezoresistive stretch sensor shaped as a conductive elastomeric body along the tube's central axis. Moreover, we detail, also by means of video clips, a step-by-step manufacturing process, which uses off-the-shelf materials and simple procedures, so as to facilitate reproducibility. [ABSTRACT FROM AUTHOR]

Green houses are being built and expanded at a breakneck pace. The green house climate directly affects plant's development, and its continuous indoor environment monitoring is critical. Most green house systems rely on manual temperature and humidity monitoring which can be inconvenient for personnel required to visit the green house daily and manually control it. This research uses a modern approach by implementing automated environmental control technology to improve green house control technology effectively. The integration of the Internet of Things (IoT) and artificial intelligence (AI) can develop a capacity for independently predicting and controlling IoT devices. The microcontroller controls the system, which serves as the central processing unit for sensors and actuators. The sensor data utilizes input parameters for the microcontroller, which processes it using the long short-term memory (LSTM) approach to anticipate output parameters for controlling actuators, such as fan exhaust, misting, and motor control. Intelligent control is not placed directly on the embedded system but on a framework known as Laravel through the results of knowledge trained by the LSTM method. Using the traditional embedded system, no data can be learned using only simple conditioning. The test findings from the LSTM training data obtained that the learning rate was less than 0.002 with a total of 250 steps, where the results were processed from the accumulation of data every minute for one month, are near to a good value. Consequently, the proposal can accurately forecast the actuator control in three minutes based on data collected from the accumulated data in the preceding three minutes. The system will collect data for future use to anticipate and optimise the melon product. The primary purpose of using AI, IoT and LSTM is that the system can see the wide range of agricultural applications by taking into account several other complex parameters, each owned by LSTM to be applied using IoT devices, so that they can be will be applied directly using publish and subscribe method. [ABSTRACT FROM AUTHOR]

Morphing aircraft can change its aerodynamic configurations to obtain optimized aerodynamic performance. Smart material actuator and flexible skin are the key technologies of morphing aircraft. Smart materials have the advantages of light weight，simple structure，and large driving force. Flexible skin can meet the requirements of large deformation and withstand local aerodynamic loads，both of which have very good application prospects. In this paper，the research of actuators made of shape memory alloys，piezoelectric materials and magneto strictive materials is introduced. The development of flexible skin based on material elasticity and structure design is analyzed. The related research issue and interests are summarized and prospected.

Enhancing the transparency of high-transmission-ratio linear actuators is crucial for improving the safety and capability of high-force robotic systems having physical contact with humans in unstructured environments. However, realizing such enhancement is challenging. A proposed solution for active body weight support systems involves employing a macro–mini linear actuator incorporating an electrorheological-fluid brake to connect a high-force unit with an agile, highly back-drivable unit. This paper introduces the use of an electromagnetic (EM) brake with reduced rotor inertia to address this challenge. The increased torque capacity of the EM brake enables integration with a low-gear-ratio linear transmission. The agile translation of the endpoint is propelled by a low-inertia motor (referred to as the “mini”) via a pulley-belt mechanism to achieve high transparency. The rotor of the EM brake is linked to the pulley. Damping modulation under high driving force is achieved through the adjustment of the brake torque relative to the rotational speed of the pulley. When the brake is engaged, it prevents any relative motion between the endpoint and the moving carrier. The endpoint is fully controlled by the ball screw of the high-force unit, referred to as the “macro”. A scaled prototype was constructed to experimentally characterize the damping force generated by the mini motor and the EM brake. The macro–mini linear actuator, equipped with an intrinsic failsafe feature, can be utilized for active body weight support systems that demand high antigravity force.