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In the process industry, the actuator has complex operating processes. Its steady working conditions are easy to change. Moreover, it is in a dynamic process for long periods of time. These phenomena reduce the accuracy and timeliness of many condition monitoring (CM) methods. In this paper, a fault detection mechanism considering the complex operating processes of the actuator is proposed. One of its main feature is that it can detect faults under steady state regardless of variable load changes. The other is that it has ability to detect faults during dynamic processes refusing the interference of nonlinearity and dynamic characteristics. Firstly, an actuator data model library based on historical data is established offline. Secondly, in the online situation, after the R indicator divides the testing data into steady state or dynamic, it is input into the model library to obtain a standard training set. Finally, the steady-state/dynamic fault detection module will determine whether a fault has occurred based on the testing data and the training set. Moreover, open-loop experiments based on the DAMADICS (Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems) platform and closed-loop experiments based on the water tank system are designed. These experiments show that, compared with other methods, the proposed fault detection framework has better monitoring performance during complex operating processes of actuators. • A novel actuator fault detection method is proposed. • It can deal with various complex operating processes containing steady and dynamic state. • It contains two novel extended non-negative matrix factorization algorithms. • The presented mechanism is verified by simulations and experiments. [ABSTRACT FROM AUTHOR]

In this paper, we propose a method for taking into account uncertainties of a micro-pump system using Shape Memory Alloy (SMA), based on the perturbation method. The proposed method is used to determine the thermo-mechanical response of a system. Comparisons with the mean value reference solution, illustrate the efficiency of the proposed method. The results are discussed in order to investigate the influence of the most influential parameters of the thermomechanical SMA model. The simulation results are obtained by the proposed method for static analysis with uncertainties.The perturbation method results are compared with the mean value reference solution. The results are discussed in order to investigate the influence of the Young's modulus E, the two transformations strain magnitude ɛ t r a c T and ɛ t r a c T F A , the martensite start M s and austenite finish A f temperatures and the stress reorientation F ε on the static response of a micro-pump system. [ABSTRACT FROM AUTHOR]

• A real-time hybrid testing based on shaking table and actuator is proposed for cable tray system. • The proposed method is validated by numerical simulations. • The proposed method is experimentally validated by one cable tray system. For precisely disclosing the seismic performance of cable tray systems, one novel Real-Time Hybrid Testing based on Shaking Table and Actuator (RTHT-STA) is proposed in this paper. In the proposed method, one shaking table is used to simulate the ground motion, and one servo-hydraulic actuator controlled with displacement mode is set up on the shaking table for truly simulating the transverse shear boundary conditions between the numerical substructure and the experimental substructure of cable tray systems. The advantage of the proposed method is accurately realizing the loading requirements of high-precision large deformation on cable tray systems. The effectiveness and accuracy of the proposed method are validated by numerical simulations and experimental tests. The experimental results show that the real-time hybrid testing system is stable and reliable. The correlation coefficients between the results of the proposed method and those of the traditional shaking table tests are higher up to 91.78%. The results indicate the effectiveness and the high accuracy of the proposed RTHT-STA for cable tray systems. The RTHT-STA provides an economical and precise investigation strategy for disclosing the seismic performance of cable tray systems and may have broad application prospects in the field of communication engineering and civil engineering. [ABSTRACT FROM AUTHOR]

In this paper, a novel actuator in the form of a Kagome truss composed of shape memory alloy (SMA) wires and common metallic wires is described. In the actuator, the SMA wires play dual roles as load supporters and actuating elements. The intersections between the SMA wires and between the SMA wires and the common metallic wires were joined by using shrinkable tubes, which induced the kinematically compatible buckling of the columns of SMA wires under compression, consequently enabling the large actuation displacement of up to 30% of the height with some sacrifice of the load capacity. An analytic solution was derived using the elementary mechanics of buckling and geometric relation of curved column, which gave fairly good estimation of the behavior of the Kagome actuator for the deformation and actuation stages, based on the behavior of a single SMA wire. The lightness and large actuation range of this actuator appear to be useful for practical applications. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates the electro-mechanical behaviour of a thick, laminated actuator with piezoelectric and isotropic lamina under externally applied electric loading using a new two-dimensional computational model. The elastic core is relatively thick and thus it is modelled by Timoshenko thick-beam theory. Although the piezoelectric lamina is a beam-like layer, it is formulated via a two-dimensional model because of not only the strong electro-mechanical coupling, but also of the presence of a two-dimensional electric field. It is shown in this paper that a one-dimensional model for the piezoelectric beam-like layer is inadequate. The piezoelectric model is constructed within the scope of linear piezoelectricity. The actuation response is induced through the application of external electric voltage. Under the strong coupling of elasticity and electricity, the strain energy and work of electric potential are presented. The electro-mechanical response of the laminated Timoshenko beam is formulated and determined via a variational energy principle. Numerical examples presented illustrate convincing comparison with finite element solutions and existing published data. New numerical solutions are also presented to investigate the geometric effect on the electro-mechanical bending behaviour. [Copyright &y& Elsevier]

At first a detailed fast shutter design was finalized for the ITER core charge exchange recombination spectroscopy (CXRS) diagnostic. The shutter has approximately 70 kg of mass and a length of 2.1 m. It operates in fractions of a second (0.7 s) protecting critical optical components against degradation and providing means of calibration for the optical system. The shutter structure is driven by a bidirectional frictionless helium actuator, with forces and axial strokes of 3.4 kN and 2 mm respectively. The shutter structure consists of: (a) two blades made of CuCrZr and stainless steel, calibration surfaces (currently Al 2 O 3 ) on the top and on the bottom a protective TZM (Mo–0.5Ti–0.08Zr) screens, (b) two arms interconnected that form one cooling circuit including the blades, (c) a bumper system to limit the arms movement, and (d) a support. A description of these components and their functions are given in this paper, followed by some issues, and their corresponding solutions or ongoing investigations, encountered during the design work. Detailed manufacturing drawings have been developed as the deliverable final product of this design stage, and are used in the prototyping phase which includes testing, numerical benchmarking, and validation of the shutter concept. [ABSTRACT FROM AUTHOR]

Soft actuators with large deformation and high stability in response to multi-stimuli are highly demanded in biomimetic applications. However, most of the present actuators driven by a single stimulus often exhibit low performance and high energy consumption. In this work, a sandwich structural soft actuator (MPDMS/MXene/PTFE) which possesses electrothermal/magnetic coupling actuation is fabricated by combining magnetic NdFeB/Polydimethylsiloxane (MPDMS) composite layer, MXene film, and PTFE tape together. Due to the large difference of thermal expansion coefficient between MPDMS film and PTFE tape, the soft actuator shows a wonderful electrothermal actuation and the bending deformation can reach to as high as 353° under a 3 V power supply. The excellent electrical conductivity of MXene component endows the sandwich film with good thermal management performance, thus the soft MPDMS/MXene/PTFE sandwich films can be applied in the thermal treatment of body and thermal imaging. Most importantly, the soft actuator also exhibits a typical magnetic biomimetic actuation and the programmable actuation performance of the dragonfly actuator can be demonstrated by both experiments and finite element simulations. Eventually, the electrothermal/magnetic coupling actuation is successfully applied in an intelligent crawling robot to overcome the traditional inchworm movement simulation. A dual-mode biomimetic soft actuator based on MPDMS/MXene/PTFE with excellent electrothermal and magnetic drive performance is developed. The soft actuator enables to prepare grippers for transferring objects and assemble the wings of a biomimetic dragonfly in a magnetic field. Finally, a crawling robot is developed to demonstrate the electrothermal/magnetic coupling actuation. [Display omitted] • The highlight of this work is: • The MPDMS/MXene/PTFE soft actuator presents both electrothermal and magneto-actuated deformation behaviors. • The soft actuator shows a wonderful electrothermal actuation and the bending deformation can reach to as high as 353° under a 3 V power supply. • The finite element analysis model can provide design guidance for the deformation process of bionic actuator with complex structure. • The soft actuator strategy presented in this paper is expected to be useful for the development of bionic intelligent actuators with multi-stimulus response. [ABSTRACT FROM AUTHOR]

Abstract: For the ITER core charge exchange recombination spectroscopy (CXRS) upper port plug #3 (UPP) diagnostics, a fast shutter is necessary for the first optical mirrors. The shutter concept for the reference CXRS layout has been well developed and studied focusing on the structure dynamic behavior. This paper presents two shutter concepts for the new baseline layout. Concept-1 is similar to the reference concept, including the helium actuator attached to the diagnostic shielding module (DSM) in the primary vacuum. Concept-2 considers the actuator outside the primary vacuum. It is attached to the back side of the UPP and connected to the shutting mechanism with a push–pull rod. Assembly and disassembly, actuator location, and actuation type are key issues for concept assessment. For a feasibility study, two different leak cases for the shutter concepts have also been analyzed. Concept-1 requires a specialized actuator design compatible with the in-vessel conditions. The actuator size is limited by the lack of available space in the DSM. This option needs complex procedures to access the actuator for maintenance. Concept-2 allows the use of standard pneumatic/hydraulic actuators and other industrial components. Space allocation is needed inside the UPP to accommodate the push–pull rod system. Concept-2 allows independent maintenance procedures for the actuator(s) and the shutting mechanism. It was generally concluded that both options are suitable for the new baseline layout, and are to be studied in detail. [Copyright &y& Elsevier]

Abstract: The behaviour of a piezoelectric actuator is strongly affected by the bonding condition along the interface between the actuator and the host structure. The current paper represents an analytical study of the static effect of the mechanical and geometrical properties of the adhesive layer on the coupled electromechanical behaviour of a thin piezoceramic actuator bonded to an elastic medium. An actuator model with an imperfect adhesive bonding layer, which undergoes a shear deformation, is proposed to simulate the two dimensional electromechanical behaviour of the integrated system. Analytical solution of the problem is provided by solving the resulting integral equations in terms of the interfacial stress. Numerical simulation is conducted to study the effect of the bonding layer upon the actuation process. The effect of interfacial debonding on the response of the layered structure and on the interlaminar strain and stress transfer mechanisms is discussed. [Copyright &y& Elsevier]

Abstract: A protocol for characterizing a novel light-weight actuator with high actuating capability is proposed and analyzed in this paper. The actuator is a sandwich structure composed of truss cores and smart face-sheets in which overall bending may occur when actuated. The deformation of this beam actuator is generated by varying the voltage applied at the face-sheets made up of smart material. The basic mechanical properties, such as the effective moduli of the structure, are discussed, and then optimization is designed to obtain the minimum weight or maximum achievable displacement subjected to two types of constraints. Analysis indicates that the composite trusses have higher stiffness and strength than the metal-trusses structure with the same density. The relationship between the actuating capability and geometric parameters is also investigated by numerical simulations. Compared with two corrugated-core actuators, the truss-core actuator has better actuating capability within a specific weight range. [Copyright &y& Elsevier]

Abstract: In this paper, the carbon nano-fibers (CNFs) were used to improve the performance of sulfonated poly(styrene-b-[ethylene/butylene]-b-styrene) (SSEBS) composite actuator. The SSEBS actuator, which was developed in our previous study, does not have good electromechanical performance because the SSEBS ionic polymer is too flexible and soft. CNFs as a reinforcement for the polymer membranes greatly increased the bending performance of the SSEBS actuators. The surface and cross-sectional morphologies of the CNF-SSEBS actuators were investigated by SEM observation. The results show that carbon nano-fibers were homogeneously dispersed in the SSEBS polymer matrix without local agglomeration. The bending responses of the CNF-SSEBS composite actuators under step inputs and sinusoidal excitations were compared with those of the pure SSEBS actuator. The tip displacement of the CNF-SSEBS actuator was much faster and larger than that of the pure SSEBS actuator. [Copyright &y& Elsevier]

[Display omitted] • One monolayer Janus bio-nanocomposite film with stimulus response is developed. • Janus structure and bonding intensity is obtained by incorporating nanocellulose into PVA. • Asymmetric structure, good mechanical properties, and water-resistance are realized. • Janus bio-nanocomposite film exhibits a smart and controllable responsiveness to salts. • Janus bio-nanocomposite film based actuators are controllably designed and explored. Stimuli-responsive materials have been increasingly explored to construct actuators and develop soft robots. Herein, one strategy via regulating lignin-containing cellulose nanofibrils (LCNF) distribution in PVA network followed by alkaline treatment (AT) and pre-stretching to fabricate bio-nanocomposite derived Janus films with stimulus response is proposed. LCNF/PVA-AT film displays obvious asymmetric structure, good mechanical properties, and water-resistance. Based on Janus structure and Hofmeister effect of PVA in salt solution, the applied pre-stretching treatment further enables the as-prepared LCNF/PVA-AT film with an excellently smart and controllable responsiveness to salt solutions. In addition, by adjusting some factors including length–width ratio of the film, salt type and concentration, the deformation degree and response/recovery time of LCNF/PVA-AT film and its based actuators can be controllably designed. The study will enrich the development of green, sustainable and biodegradable polymers derived Janus films, and expand their wide potential applications in multifunctional actuators. [ABSTRACT FROM AUTHOR]