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As the main prerequisite for flow in microfluidic chips, micropumps have always been the core component of microfluidic systems. With the continuous development trend of the three dimensions and high integration for microfluidic systems in recent years, combining the characteristics of micro and drivable fluid flowing in 3D space is the current mainstream research goal in the functions of the micropumps. Here, based on the continuous electrowetting effect in a confined space of the Ga‐based liquid metal (LM), an LM driving micropump structure is proposed that enables fluid to be pumped up to 200 mm in height, which meets the major demands of microfluidic system working environments. The pumping mechanism is experimentally analyzed and demonstrated, as well as the working performance of the micropump under different output modes (continuous flow and pulsatile flow). The feasibility of this micropump is also verified through a fluid pumping experiment in complex shaped channels and a temperature management experiment in 3D space. This work is envisaged to expand the function and application area of the electric actuators driven by the Ga‐based LM and provide new support for micropumps in the 3D microfluidic chip system. [ABSTRACT FROM AUTHOR]

To the challenges posed by the complex structure and low reliability of existing hydraulic actuators used for more electric aircraft landing gear, this paper proposes an optimised design method for an electric actuator based on the principles of tubular permanent magnet linear motor employing a Halbach array. For this electric actuator, a subdomain model considering the longitudinal end effect is established by setting virtual permanent magnet regions at both ends of the Halbach array. The effectiveness of the proposed method is verified through a comparison with the finite element method. Subsequently, a surrogate model is developed using the proposed subdomain model, and an uncertain optimisation model considering machining and assembly errors is developed based on the interval possibility and the interval order theory. Compared to its initial design, the optimised structure increased the average thrust by 13.4% and reduced the thrust ripple rate by 87.2%, significantly improving the overall performance of the electric actuator. Finally, prototype experiments are carried out to verify the effectiveness of the proposed subdomain method and optimised approach. [ABSTRACT FROM AUTHOR]

Sensorless control of permanent magnet synchronous motor (PMSM) can increase the reliability of electric actuators of more electrical aircraft. Numerical online parameter estimation method will enhance the performance for sensorless control methods based on sliding mode observer (SMO). However, numerical online parameter identification methods typically assume zero rotor position estimation error to ensure full rank of the identification equation set. This assumption actually leads to errors in parameter identification, resulting in steady‐state errors in rotor position estimation. This paper focuses on a compensation method for PMSM online parameter identification that takes into account rotor position estimation error. This method is used for sensorless control based on SMO, using model reference adaptive systems for online parameter identification, and no additional parameter adjustment required. Validation is conducted on a PMSM experimental platform with maximum load of 15kW. The experimental results of 1000 r/min steady state operation proved the effectiveness of the method, and the dynamic experiments with 5 and 15kW loads proved that the method has no significant adverse effect on the system dynamics. [ABSTRACT FROM AUTHOR]

Bionic robots have great potential in healthcare, rescue, and surveillance. However, most soft actuators can only realize one or two deformation modes, which largely limit the application in complex environments. This study develops electric/Infrared (IR) light/magnetic multi‐field coupling soft actuators by combining liquid crystal elastomers (LCE), liquid metal (LM) and magnetic Ecoflex (Mecoflex). Originated from the synergistic effect of the differed thermal expansion and the liquid crystal phase transition, the actuator can realize outstanding large deformations (bending angle > 300°) at ultra‐low voltages (1.0 V). In addition, by designing the molecular orientation in the LCE layer and programming the magnetization in the Mecoflex layer, the bending or helical bending deformations can be controlled under electric/magnetic and IR light/magnetic coupling actuation. Based on the complex deformation capability, bionic climbing plants and two kinds of quadrupedal robots are developed. With the structural design of the quadrupedal robots, they can flexibly switch deformations to pass through complex environments by controlling the externally applied coupling fields, which demonstrates their broad potential in practical applications. [ABSTRACT FROM AUTHOR]

The authors propose an analytical modelling approach for the linear transverse flux permanent magnet motor using the magnetic equivalent circuit method. The main focus of this study is to predict the phase flux‐linkage characteristic of the motor. Essential equations required for implementation of the model and how to solve it are described clearly so that someone can use it easily. A typical motor is selected to apply the proposed model and simulation results, including static characteristics of flux‐linkage and thrust, are presented. To validate the developed analytical model, the discussed motor is also analysed with 3D finite element method using MAXWELL software and the obtained simulation results are compared to each other. [ABSTRACT FROM AUTHOR]

In this study, task space tracking control of robot manipulators driven by brushless DC (BLDC) motors is considered. Dynamics of actuators are taken into account and the entire electromechanical system (i.e. kinematic, dynamic, and electrical models) is assumed to include parametric/structured uncertainties. A novel adaptive controller is designed and the stability of the closed loop system is ensured via novel Lyapunov type tools. To demonstrate performance and applicability of the proposed method, a simulation study is conducted using the model of a two degree of freedom, planar robotic manipulator driven by BLDC motors. [ABSTRACT FROM AUTHOR]

Agricultural mechanization although reduces the food demand and supply gap through improved and smart technologies, it also risks the lower‐limb disability of workers due to accidents that restrict them to participate in agricultural operations due to the unavailability of appropriate assistive technologies. The lack of use of ergonomics further minimizes the inclusion of female workers in farming operations. Therefore, this study is focused on the development of a sensor‐based wireless hand control system for tractor clutch and brake operation to assist lower‐limb‐disabled agricultural workers and abled females in tractor operation. Actuation force and speed of conventional clutch and brake pedals were evaluated using an integrated foot transducer and used as a reference for the design of the system (clutch: 92–310 N, 36–43 mm/s; brake: 106–329 N, 57–63 mm/s). The hand control system consists of a transmitter and a receiver node incorporating a single‐board computer, matrix keypad, voltage regulators, relay switches, wireless communication through radio frequency modules, and electric linear actuators connected with the pedals through L‐shaped clips, nuts, bolts, and chains. The response time of the developed system was determined as 100 ms and the stopping distance of the tractor using the hand control system ranged from 44.0 to 190.7 cm at a forward speed of 2.1–7.9 km/h. The ergonomic evaluation measured using the K4b2 oxygen analyzer identified the foot control usage in tractors as high energy consuming (9.7–15.1 kJ/min) compared with the hand control usage (7.3–14.1 kJ/min). Electromyography‐root mean square (EMG‐RMS) of upper limb muscle, extension digitorum was found to be highest (14.76–45.29 µV) and was significantly affected by forward speed, gender, subjects, and type of control (p < 0.01) whereas, EMG‐RMS of other selected upper limb muscles, middle deltoid, flexor carpi radialis, and brachioradialis was not significantly affected by the type of control (foot or hand). Muscle workload of all the muscles was observed within the recommended limit (<30%) during the tractor operation with the developed hand control system. The developed hand control system provides options to bypass foot‐based actuation requirement for lower limb disabled as well as female workers. The novel design requires minimal workplace and operating forces and is inclusive of operator ergonomics. [ABSTRACT FROM AUTHOR]

To improve the speed of mass transfer, a magnetic suspension platform (MSP) is used to transport the display chips. A novel 6‐DOF MSP is proposed in this paper. An improved Halbach array is used to supply the magnetic flux density. Two types of permanent magnets are utilised in the improved Halbach array. The smaller permanent magnet serves to consolidate the magnetic flux density, thereby enhancing the uniformity of the magnetic field. The finite element method is employed to analyse how variations in angle impact both the strength and uniformity of the magnetic flux density. The results show that the magnetisation direction of 45° is the most effective in terms of improving the uniformity and strength of the magnetic density. Finally, a 6‐DOF MSP prototype is manufactured. A magnetic density measurement experiment and a stable suspension experiment for the actuator are conducted. The results indicate an enhancement in the uniformity of the magnetic field within the air gap. Additionally, the maximum suspension positioning accuracy of the actuator is about 750 nm. [ABSTRACT FROM AUTHOR]

In this article, a chitosan‐based bio‐gel electric actuator with tannic acid and carboxymethyl cellulose (CMC)as cross‐linked materials was fabricated. By evaluating the output force and electrochemical characteristics of the electric actuator under different doping amounts of tannic acid and CMC, it was found that the sample with appropriate amount of cross‐linking can improve its output force, service life, specific capacitance. Infrared spectroscopy, scanning electron microscopy(SEM), and ion channel test showed that tannic acid and CMC were uniformly distributed in the chitosan matrix. The proper crosslinking was beneficial to transform the internal dense and uniform structure into a loose and porous structure, promote the migration of ions, improve the electrochemical performance of the electric actuator, and thereby improve its output performance. This study provided a facile and eco‐friendly method to construct chitosan‐based electromotive membrane with enhanced output properties. [ABSTRACT FROM AUTHOR]

Electric machines are widely employed in a variety of sectors, including automotive and aerospace industry. With the rising trend towards electrification in aviation, electric machines with increased power density and efficiency are becoming key enabling technologies, requiring the development of innovative design procedures. In this study, a preliminary design procedure for Surface Mounted Permanent Magnet Synchronous Machines (SPMSMs) intensively cooled by means of oil channels placed in the stator slots is proposed. The analytical derivation of SPMSM sizing equations, including the sub‐domain model and optimisation algorithm will be reported in detail. Indeed, both the electromagnetic and thermal equations of the machine are considered for the derivation of the sizing tool. As a result, the latter allows to capture variation of the machine design not only in terms of mechanical demands, such as power and speed, but also in terms of coolant characteristics, and can be effectively employed to perform trade‐off studies at a preliminary design stage. The proposed design tool will be used for a specific case study: The design of a high‐speed machine for an aerospace hydraulic actuator. The accuracy of the proposed design tool is validated for different parameters by comparing the results to experimental measurements performed on an existing 8‐pole 9‐slot prototype SPMSM. [ABSTRACT FROM AUTHOR]

Summary: Real‐time hybrid simulation (RTHS) is a relatively new method of vibration testing for characterizing the system‐level dynamic response of physical hardware components or substructures. With RTHS, a structural dynamic system can be partitioned into separate physical and numerical substructures and interfaced together in real time as a cyber‐physical system similar to hardware‐in‐the‐loop testing. Control actuation and sensing are used to enforce the compatibility and equilibrium conditions between the physical and numerical substructures. Since RTHS involves a feedback loop, the frequency‐dependent dynamics of the actuator transfer system can introduce inaccuracy and potential instability during closed‐loop testing. This paper presents a robust stability and performance analysis method for multi‐actuator RTHS based on concepts from robust stability theory for multiple‐input multiple‐output (MIMO) feedback control. This method involves casting the actuator dynamics as a multiplicative uncertainty and applying the small gain theorem to derive the sufficient conditions for robust stability and performance. The attractive feature of this method is that it accommodates linearized modeled or measured frequency response functions for the physical substructure and actuator dynamics. The method is demonstrated using Network for Earthquake Engineering Simulation (NEES) experimental data from a two‐actuator RTHS test of a seismically excited two‐story steel frame structure. Results show that the robust stability and performance analysis method provides a versatile and useful tool for pre‐test planning and post‐test diagnostics of RTHS tests involving multiple actuators. [ABSTRACT FROM AUTHOR]

Ultra‐reliable low‐latency communication (URLLC) has gained significant interest since it deals with short packet transmission adopted to reduce latency; however, this implies that the conventional Shannon capacity formula is not applicable, and the achievable data rate becomes a complex function of the decoding error probability and blocklength. This paper studies URLLC transmission using a time‐division multiple access scheme with an arbitrary number of actuators utilising a reconfigurable intelligent surface. The authors optimisze the weighted sum rate of this system subject to reliability, total energy, and latency constraints. For the blocklength allocation in a scenario where each actuator is allocated equal power, a closed‐form analytical solution is provided. Also, for the case of joint optimization of the blocklength and power of each actuator, an analytical solution is provided for the case of two actuators, while an iterative sequential quadratic programing method is adopted for the case of an arbitrary number of actuators. The proposed methodology provides a low‐complexity, fast solution, which is more efficient than using exhaustive search techniques. The results show that in some cases, optimization of the blocklength provides a near‐optimal solution at low complexity, while jointly optimising the blocklength and the power per actuator has an improved performance at the cost of additional complexity. [ABSTRACT FROM AUTHOR]

Amongst the various types of paddy transplanters; walk‐behind‐type transplanters are more economically viable as compared with riding‐type paddy transplanters. But, it requires more human involvement because the operator has to walk behind the two‐wheel walk‐behind‐type paddy transplanter in puddled field conditions up to about 10–22 km during a day‐long period under high temperature and humid conditions. To reduce the workload of the operator, a wireless remote‐controlled system has been developed to control the various hand control levers of walk‐behind‐type paddy transplanter through electric linear actuators and electronic control unit. The present study emphasizes the performance evaluation of the remote control system and optimizes the machine–field parameters. Response surface methodology was used with three levels of soil puddling settlement period (4, 26, and 48 h), three forward speeds (1.40, 1.85, and 2.30 km h−1) in two types of soils (light‐textured and medium‐textured). The response factors, that is, the effective field capacity (EFC) and field efficiency (FE) were found affected by forwarding speed, soil type, and soil puddling settlement period, but no significant effect was observed at the interaction level. The optimal value of soil puddling settlement period was 26 h at a forward speed of 2.0 km h−1 for light‐textured soil, whereas for medium‐textured soil, it was 30 h at 1.82 km h−1. A total saving of up to 18.18% labor requirement was observed as required in the existing walk‐behind‐type paddy transplanter. The increase in EFC was observed up to 20%, resulting the net benefit per unit area and per year has been increased up to 6.59% and 15.86%, respectively. The overall results of the field evaluation showed that the remote‐controlled system for the two‐wheel paddy transplanter would be feasible at optimized field and machine parameters. [ABSTRACT FROM AUTHOR]

Water‐responsive (WR) materials that reversibly deform in response to humidity changes show great potential for developing muscle‐like actuators for miniature and biomimetic robotics. Here, it is presented that Bacillus (B.) subtilis' peptidoglycan (PG) exhibits WR actuation energy and power densities reaching 72.6 MJ m−3 and 9.1 MW m−3, respectively, orders of magnitude higher than those of frequently used actuators, such as piezoelectric actuators and dielectric elastomers. PG can deform as much as 27.2% within 110 ms, and its actuation pressure reaches ≈354.6 MPa. Surprisingly, PG exhibits an energy conversion efficiency of ≈66.8%, which can be attributed to its super‐viscous nanoconfined water that efficiently translates the movement of water molecules to PG's mechanical deformation. Using PG, WR composites that can be integrated into a range of engineering structures are developed, including a robotic gripper and linear actuators, which illustrate the possibilities of using PG as building blocks for high‐efficiency WR actuators. [ABSTRACT FROM AUTHOR]

Light‐driven actuation of synthetic polymers is an emerging field of interest because it offers simple remote addressing without complicated hydraulic, electric, or magnetic systems. Reviews on this area predominantly emphasize on the development of mechanical motions like bending, twisting, folding, etc. However, the scientific and fundamental aspects of these materials are critical in order to expand applications and industrial relevance. Polymer actuators driven by light, not only comprise soft actuators (large deformations at low stress) but also include stiff actuators (high actuation stress at low strain). Synthetic polymeric materials with photo‐responsive additives together with underlying mechanisms, processing parameters, and final properties are required to broaden the scope of the field. In particular, parameters like actuation stress, actuation strain, and work capacity have been given limited attention in the past and are discussed extensively. This work gives a comprehensive critical review on all light‐driven synthetic polymer actuators, their actuating mechanisms, and materials. A holistic perspective together with an insight into future prospects can lead academia and industry toward future innovations and applications of these exciting functional materials. [ABSTRACT FROM AUTHOR]

The hydraulically amplified self‐healing electrostatic actuator is an emerging driving component for soft robotics, which is composed of a flexible dielectric polymer shell that is partially covered by conductive electrodes and filled with a liquid dielectric. However, the low permittivity and dielectric strength of the polymer shell remain a challenge that limits the actuator performance. Herein, a Peano‐hydraulically amplified self‐healing electrostatic actuator is constructed by innovatively integrating a bilayer polymer shell for combined favorable properties of high dielectric strength, dielectric permittivity, and elastic modulus. Compared with a traditional single‐layer shell actuator, the new bilayer actuator architecture generates an increased strain (164%) at 5 kV and improves load‐bearing capability (620 mN) at 6 kV, thereby providing a significantly enhanced actuation performance. The new actuator is further applied in driving a ratchet system, which converts the reciprocating motion of the actuator into a rotating motion and a flexible output torque, in order to protect the rotating components from impact. The high strain and load characteristics of the bilayer configuration and the easy‐to‐deform characteristics of the new actuator design make it an attractive approach to fabricate complex geometries and achieve a variety of motion modes in soft systems. [ABSTRACT FROM AUTHOR]

A new electrode architecture for dielectric elastomer actuators (DEAs) is introduced in which a soft polyacrylate film is coated with a biphasic mixture of silver, indium, and gallium. This Ag–In–Ga coating functions as a soft electrode that is ultrathin, highly compliant, highly conductive, stretchable, and non‐smearing. Compared to carbon grease, sputter‐deposited metal coating, and particle‐filled conductive elastomers, this biphasic coating exhibits a unique combination of solid‐state integrity, extreme mechanical compliance, and low electrical resistivity. Herein, how DEAs with an Ag–In–Ga coating exhibit a 5× larger actuation speed compared to carbon‐coated dielectric films is shown. The influence of coating thickness on the mechanical stiffness and blocking force is also examined. [ABSTRACT FROM AUTHOR]

Dielectric elastomer actuators (DEAs) are energy efficient, compact, and operate silently. DEAs consist of an elastomer membrane sandwiched between two stretchable electrodes. Optimizing the quality of both the elastomer and the stretchable electrodes is essential to improve the DEAs performance. Herein, novel strategies are reported to achieve fast, reliable, and low‐cost fabrication of DEAs. The strategies utilize a soft brush to directly pattern carbon nanotube (CNT) powder on the elastomer membrane and tune the mechanical and surface‐adhesiveness characteristics of a polydimethylsiloxane (PDMS) membrane by altering the mixing ratio of the curing agent and base polymer. A uniaxial engineering tensile test on PDMS indicates that a softer material is formed when less curing agent is used. The softer PDMS has a sticky surface, which allows the CNT powder to be physically bound to the surface. Field‐emission scanning electron microscopy (FE‐SEM) images prove that the strong CNT network is formed on the surface of the elastomer. The electromechanical investigation also indicates that the electrical conductivity is improved for a stickier PDMS surface. The optimal performance of PDMS 30‐1 in static and cyclic DEA tests shows that the brushing of CNT combined with soft and sticky elastomer membranes can increase the DEA performance. [ABSTRACT FROM AUTHOR]

The first dielectric elastomer actuators based on electroactive nanocomposites with octakis(phenyl)‐T8‐silsesquioxane (phenyl‐T8), obtained ex‐situ, used as voltage stabilizer filler for silicone elastomers are reported. The incorporation and homogeneous dispersion of crystalline phenyl‐T8 in percentages of 2.5, 3.5, 5, and 10 into the amorphous matrix consisting in a polydimethylsiloxane‐α,ω‐diol with Mn = 240,000 g/mol was successfully achieved by solution mixing and crosslinking. For the sample with the best actuation performance (that containing 3.5 wt.% filler), an optimized filled elastomer was obtained by dispersing 3.6 wt. % phenyl‐T8 in the matrix using a suitable surfactant (Pluronic L81), thus gaining an increased electrical breakdown of 30% compared with the pristine sample. Beside dielectric strength, the matured films were characterized in terms of morphology, mechanical, dielectric and actuation tests. In spite of structural incompatibility between the filler and the matrix, the obtained materials are soft elastomers showing high strain (~800%) and low Young's modulus of 50–100 kPa. The use of phenyl‐T8 in a silicone matrix lead to electroactive films with slightly increased lateral actuation strain and electric breakdown strength. [ABSTRACT FROM AUTHOR]

Dielectric elastomer actuators (DEAs) have shown promises in numerous applications such as bio‐inspired robotics, tactile displays, tunable optics, and microfluidics, owing to their unique combination of large actuation strain, high energy density, and light weight. However, the practical applications of the DEAs have been hindered partly due to their poor reliability and durability under high‐strain actuation. A major failure mechanism is from the localized electrical breakdown. Compliant electrodes with self‐clearing capability have been studied to prevent premature failures. Here, an interpenetrating bilayer compliant electrode comprising a thin layer of a water‐based polyurethane (WPU) overcoated on an ultrathin single‐walled carbon nanotube (SWNT) layer is reported. The thin polyurethane layer serves as the dielectric barrier to suppress corona discharges of the nanotubes in air. The SWNT+WPU bilayer electrode has the capability to self‐clear at the breakdown sites, enhancing the fault tolerance and mendability of the DEA at a large‐strain actuation. Stable actuation at 150% area strain for 1000 cycles under square‐wave voltage and 5.5‐h continuous actuation at a constant voltage have been achieved for acrylic elastomer‐based DEAs. [ABSTRACT FROM AUTHOR]

The dynamical characteristics of the electrical and mechanical domains are usually detected by means of electromechanical model of piezoelectric actuator; this is because it manages extremely small displacements in the range from 10 pm (1 pm = 10−12 m) to 100 μm. This manuscript is dedicatedly written on the fractional modeling of electromechanical model of piezoelectric actuator through modern fractional definitions, namely, Atangan–Baleanu and Caputo–Fabrizio fractional operators, which are based on capturing the full memory effects with and without Markovian and non‐Markovian properties. The modeled governing partial differential equation of displacement is solved by means of Laplace transform method. The investigated solutions of displacement have been expressed in terms of Fox‐H function and series format for avoiding the involvement of gamma functions. A comparative analysis is performed graphically between solutions obtained from Atangan–Baleanu fractional operator and Caputo–Fabrizio fractional operator. Our results suggest that displacement via Atangan–Baleanu fractional operator dominates than displacement via Caputo–Fabrizio fractional operator for controller design even to bypass the hysteresis effect. Additionally, comparison of both fractional techniques on displacement suggests that the utilization of the frequency domain is much more effective than the displacement via classical approaches. [ABSTRACT FROM AUTHOR]

This article analytically investigates the temperature influence on the performance of laterally constrained dielectric elastomer actuators. The effects of both temperature and stretches on the permittivity are taken into consideration. The governing equations of state are established by modeling the actuator as a thermodynamic system of three degrees of freedom. Various failure modes, including electromechanical instability, electric breakdown, loss of tension, and tensile rupture are considered to restrict the operation state and to determine the region of allowable state. Numerical calculations are performed to depict the variations of some important physical quantities with generalized coordinates and to gain insight on the influence of temperature on the critical curves of failures. It is shown that the temperature has obvious effects on the operation state and the allowable region. The present results can be used for designing and optimizing an actuator, and the present approach can be extended to other kinds of dielectric elastomer actuators with complex geometries. [ABSTRACT FROM AUTHOR]

The influence of the electrode length and the voltage pulses on the discharge characteristics of the surface dielectric barrier discharge actuators were investigated numerically by using the plasma kinetic model. The governing equations including the coupled continuity plasma discharge equation, drift‐diffusion equation, electron energy equation, Poisson's equation, and Navier–Stokes equation were solved in quiescent air at atmospheric pressure. The results show that the shorter pulse rising time results in higher discharge characteristics, more intense discharge, and bigger discharge region. Differently, the compared discharge characteristics for the electrodes with different lengths prove that the length of the powered and ground electrodes has little effect on the surface dielectric barrier discharge driven by nanosecond pulsed voltage. [ABSTRACT FROM AUTHOR]

Soft actuators driven by pneumatic or electric means are heavy and clumsy with physical connections, which hinders their applications in human–machine interactive, wearable, and biomedical fields. Herewith, a light fabric bimorph actuator is reported that is driven wirelessly by optical, thermal, and magnetic energy sources. Being fabricated by laminating electrically conductive fabric and biaxially oriented polypropylene film, the actuators show a large bending curvature of 0.75 cm−1 with optical stimulus and 0.55 cm−1 with magnetic stimulus, a response time of 0.27 s with a bending angle of 100° to magnetic stimulus, more than twice faster than previously reported bimorph actuators. Their remarkable performance is attributed to the optimal structural design based on a verified Timoshenko model, electrothermal and optical properties of the conductive fabric coated by copper/nickel. It is greatly enhanced by the large difference of thermal expansion coefficients between the film and fabric. Various wireless controlled prototypes are demonstrated, including a soft gripper, soft kickers, and artificial blooming flowers, illustrating a new way to mass produce cost‐effective bimorph actuators via a simple, green, and fast approach for applications in robots, wearable, and functional textiles. [ABSTRACT FROM AUTHOR]

A methodology for the experimental modelling of the electric actuators of a multirotor is presented in this work. These actuators are usually brushless DC motors which are driven by electronic speed controllers in an open loop. The duty cycle of a PWM signal, generated by the electronic control unit, is the input of the electronic controller. However, during the control design procedure for the multirotor, it is important to account with a model of the actuators as its dynamical features define the closed-loop performance of the overall aircraft. Hence, a procedure, based on low-cost electronic components, to obtain approximated transfer functions of the actuators of a multirotor is presented. Moreover, as the proposed signal processing algorithms are simple, the computational capabilities of the required embedded system are also low. Given that different control schemes require different information from the actuator, two models were obtained: a duty cycle vs. angular velocity transfer function and a duty cycle vs. consumed current transfer function. The effectivity of the proposal is validated with experimental results on common electric actuators of a multirotor. [ABSTRACT FROM AUTHOR]

This article presents a design of a high thrust density moving magnet linear actuator for linear refrigerator compressor. The shape of permanent magnet (PM) shows great effect on cost, fabrication and magnetic flux density generation in the actuator. Axially magnetised disk shaped PMs are low cost and convenient for fabrication. Moreover, axially magnetised PMs generate high flux density in a specific direction compared to radial magnets. This paper investigates the design of axially magnetised moving magnet linear oscillating actuator (LOA) which operates on single phase alternating supply. Additionally, an alternative path is proposed for the return of magnetic flux from mover to the stator. Using finite element method (FEM) tools, all the parameters of LOA are optimised. Moreover, with the help of a specially designed experimental setup, FEM simulation results are validated. This actuator demonstrates great advancement in thrust force density, motor constant and output power compared to the size of proposed LOA. [ABSTRACT FROM AUTHOR]

Simulation of musculoskeletal systems using dynamic optimization is a powerful approach for studying the biomechanics of human movements and can be applied to human‐robot interactions. The simulation results of human movements augmented by robotic devices may be used to evaluate and optimize the device design and controller. However, simulations are limited by the accuracy of the models which are usually simplified for computation efficiency. Typically, the powered robotic devices are often modeled as massless, ideal torque actuators that is without mass and internal dynamics, which may have significant impacts on the simulation results. This article investigates the effects of including the mass and internal dynamics of the device in simulations of assisted human movement. The device actuator was modeled in various ways with different detail levels. Dynamic optimization was used to find the muscle activations and actuator commands in motion tracking and predictive simulations. The results showed that while the effects of device mass and inertia can be small, the electrical dynamics of the motor can significantly impact the results. This outcome suggests the importance of using an accurate actuator model in simulations of human movement augmented by assistive devices. Novelty Demonstrating the effects of including mass and internal dynamics of the actuator in simulations of assisted human movementA new OpenSim electric motor actuator class to capture the electromechanical dynamics for use in simulation of human movement assisted by powered robotic devices [ABSTRACT FROM AUTHOR]

High reliability and security have become the hallmarks of complex electromechanical systems. Owing to the difficulties in fault data collection, ambiguity and uncertainty have been inevitably associated with complex electromechanical systems. Thus, the ability to perform reliability evaluation using scarce fault data is of immense significance to these machines and is the focus of this study. A similarity based cloud model is proposed to evaluate the running state of complex electromechanical systems. By combining objective and subjective factors, the reliability of complex electromechanical systems is evaluated by calculating the similarity between the cloud models of actual and standardised states. Next, the inverter of an offshore wind turbine is used to verify the accuracy and effectiveness of the proposed approach. The cloud model based framework for reliability evaluation inherits the preponderance of the uncertainty problem, overcomes the drawbacks of the current reliability approaches, and provides a theoretical basis, as well as a practical approach for the maintenance and repair of complex electromechanical systems with missing fault data. Additionally, it also provides a new methodology for solving the uncertainty problems caused by paucity of data. [ABSTRACT FROM AUTHOR]

To meet the challenges posed by the increasing use of electrical actuation on board next generation aircraft, advanced experimental testing capabilities are required to investigate optimal system design, performance and control. Rapid control-prototyping and hardware-in-the-loop (HiL) techniques provide the ability to expedite experimental testing, allowing for elements of the system to be validated without requiring fully realised hardware. Previously, this would require large scale laboratory setups, where the entire electrical and mechanical system would have to be designed and built prior to experimental testing. This study presents the development of a laboratory HiL and rapid-prototyping test-bench, capable of investigating the performance of actuator motor control schemes, under a variety of test conditions. Experimental testing is carried out using a laboratory test-bench, demonstrating the performance of landing gear electromechanical actuator controls under power system and load transients. [ABSTRACT FROM AUTHOR]

Conventional flap and slat high-lift surfaces actuation systems in a commercial aircraft consist of actuators mechanically connected via a transmission system across the wingspan, driven from a centralised power drive unit comprising of a hydraulic, electric, or hybrid hydraulic/electric motor arrangement. The permanent coupling to the shafts makes the entire flap system move in unison, as do the slats. This paper will investigate and discuss different potential system architecture, and present the benefits associated with such architecture. It will also present the advantage that can be linked to a full electric flap configuration. [ABSTRACT FROM AUTHOR]

This paper assesses the advantages, drawbacks, and overall suitability of different soft-stop techniques to provide smooth deceleration of ultra-fast linear actuators used in hybrid HVDC breaker designs, with the help of FEA simulations. The paper compares active and passive damping techniques in terms of efficacy, energy consumption, and interference with the ultra-fast operation needed from the actuator. The possibility of combining active and passive damping techniques is discussed. [ABSTRACT FROM AUTHOR]

An electric oil pump (EOP) must be used to supply oil for actuators in the hybrid continuously variable transmission (CVT) on the launch state of vehicle. To develop this EOP, the current CVT‐based hybrid schemes and the use of EOP on traditional automatic transmissions are analysed. Permanent magnet synchronous motor (PMSM) type is chosen as the power source of the developed EOP for its advantages of high efficiency and long‐life cycle. The PMSM EOP motor is designed and simulated by ANSYS EM. Based on the parameters of the simulation results, the sensor‐less speed controller of the EOP is designed. Then, the model of the EOP and its load CVT hydraulic system are established by Simulink and AMEsim, respectively, for joint simulation. The simulation results show that the EOP can respond to the speed command request quickly, and when the load of the hydraulic system changes it also can keep the speed stable. Finally, based on the developed prototype of EOP and hybrid CVT, the correctness of the developed EOP and its sensorless speed controller are verified by bench test. [ABSTRACT FROM AUTHOR]

This paper presents the development and control methodology of a military rescue robot for a casualty extraction task. The new rescue robot (HURCULES) equipped with electric actuators for the casualty extraction task on the battle field is introduced. In this paper, mechanical designs of the HURCULES are described in detail. One of the noticeable features in the mechanical design is to use the worm gear in the joint to maintain the safety of the casualty even with power‐off and to reduce the energy through a selected operating mode. Moreover, unlike the upper body of a conventional humanoid robot, the chest plate is installed and used to properly distribute the casualty's weight to the dual‐arm manipulator and the chest plate when carrying the wounded person. The HURCULES is valuable because the rescue robots for use on the battle field are very rare. And, the HURCULES is the first rescue robot for use on the battle field in South Korea. Primarily, a semiautonomous control strategy is applied to the HURCULES. The maneuvering stability of the HURCULES is needed when approaching and escaping a casualty while maneuvering on uneven terrain, and it maintains autonomously by the HURCULES. A variety of maneuvering experiments on various terrains were conducted, and satisfactory results for the casualty extraction task were obtained. In particular, the field experiments in this paper were performed at an accredited test site. Besides, additional experiments were conducted to enhance the field applicability. [ABSTRACT FROM AUTHOR]

This study presents modelling and control of a high-voltage ratio flyback converter for driving capacitive loads including smart material dielectric elastomer actuators (DEAs). These actuators find various applications including artificial muscles, optical devices, smart skin, and acoustics but require high actuation voltages. To this end, a high-voltage bidirectional flyback converter for driving a capacitive load is studied in terms of modelling and control and applied to a DEA. The state-space model of the converter is obtained for the capacitor charge and discharge modes when the converter operates in the continuous conduction mode and used to obtain a load voltage controller using the feedback linearisation method. The converter can be used to regenerate the capacitor charge into the dc source. The proposed hardware and control strategy was built and validated by driving DEA capacitive loads operating at high voltages around 4 kV. The experimental results are presented which validate the performance of the proposed converter and its control strategy. [ABSTRACT FROM AUTHOR]

This study presents the design of an electric motorisation for a landing gear. The concept of More Electric Aircraft is currently with one of the major concerns of all aircraft manufacturers and equipment suppliers throughout the world. The objective consists of eliminating, to the greatest extent possible, the use of any actuator containing fluid pressure and increasing the use of electric actuators. This applies to all airplane orders and accessories. The choice of this motorisation was to design synchronous machines with toothed coupling. When actuators of very high mass performance are required, the use of this type of actuator is an interesting solution, compared with conventional actuators with polar coupling. The principles used in our design method are based on two‐dimensional finite‐element simulations. The study and the calculation can be performed in two dimensions from a simple element called an elementary pattern, representing the interaction of magnets with stator teeth. Following a summary presentation of this type of actuator and its dimensioning, two prototypes are presented. To replace the hydraulic cylinders in the landing gear of an A320 aircraft, a vernier machine, and a multi‐air gap linear motor has been dimensioned, manufactured and tested. [ABSTRACT FROM AUTHOR]

Abstract: This paper is concerned with the formal deduction of piezoelectric plate models in microstretch elasticity, by means of an asymptotic analysis with respect to a small parameter ε, being the thickness of the plate. Two different boundary conditions pertaining to electric quantities are considered, leading to two different models: the sensor model and the actuator model, respectively. Each of the two plate problems turns out to be decoupled into a bending problem and a certain microstretch membrane problem, partially coupled with the electric behavior. [ABSTRACT FROM AUTHOR]

SUMMARY: This paper reports a piezoelectric in‐plane resonant actuator for a speckle dissolution device used in a laser‐type projector. An optical diffuser is oscillated by this actuator to reduce the coherency of a scanned laser beam. A PZT unimorph actuator combined with a Moonie‐type displacement amplifier and a resonant structure was used to obtain a large displacement. The L18 design of experiment method was used for the optimal design. Both 1‐axis and 2‐axis actuators were designed and fabricated. The maximum displacement as high as 239.5 μm at a resonance frequency of 325.2 Hz was obtained for the 1‐axis actuator, and the maximum displacements of 109.5 μm and 67 μm for l.5 Hz for both x‐ and y‐direction at resonance frequencies of 621.5 Hz and 288.5 Hz were obtained for the 2‐axis actuator (10 V). The actuator was also tested with a dummy optical diffuser to evaluate the influence of the additional mass. [ABSTRACT FROM AUTHOR]

Answer: c. 7.2 mg/L/h b Oxygen uptake rate is the amount of oxygen consumed in a given time. The pressure at which the blower stops running b. The pressure that's the maximum the blower can produce c. The pressure against which there's no more flow through the blower d. The pressure where the inlet and outlet pressures are identical B 4. I Cryptosporidium i and turbidity b. I Cryptosporidium i , I Giardia i , and turbidity c. I Cryptosporidium i , I Escherichia coli i , and turbidity d. I Giardia i and I Escherichia coli i B 2. [Extracted from the article]

Compared with the fault diagnosis, detection, and isolation literature, very few results are available to discuss control algorithms directly for multi-input multi-output nonlinear systems with both sensor and actuator faults in the fault tolerant control literature. In this work, we present a fault tolerant control algorithm to address the system output stabilization problem for a class of multi-input multi-output nonlinear systems with both parametric and nonparametric uncertainties, subject to sensor and actuator faults that can be both multiplicative and additive. All elements of the sensor measurements and actuator components can be faulty. Besides, the control input gain function is not fully known. Backstepping method is used in the analysis and control design. We show that under the proposed control scheme, uniformly ultimate boundedness of the system output is guaranteed, while all closed-loop system signals stay bounded. In the cases where the sensor faults are only multiplicative, exponential convergence of the system state variables into small neighbourhoods around zero is guaranteed. An illustrative example on a robot manipulator model is presented in the end to further demonstrate the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

This study presents a discrete‐time sliding mode control (DSMC) with an input filter for a low damping electro‐hydraulic actuator (EHA) suffering from large control volume variation. Non‐switching type reaching law and one‐step delayed estimation of disturbance are combined in the DSMC. Different from existing DSMC strategies which view parametric uncertainty as a lumped bounded disturbance, the influence of parametric uncertainty on the system stability is analysed, which results to a two terms iterative expression of state. The stability criterion for this iteration is put forward. To stabilise the EHA that has a large control volume variation, a first‐order input filter for the control input is introduced. The disturbance resulting from the input filter is expressed and the stability criterion with the input filter is derived. Both simulation and experimental results show the effectiveness of the proposed approach on the position tracking of the EHA with large volume variation. [ABSTRACT FROM AUTHOR]

Liquid‐metal pixels are used to demonstrate a frequency‐tunable dipole antenna that can be reconfigured for horizontal or vertical polarisation. Each dipole consists of 14 pixels, each of which can be electrically actuated with the liquid metal Galinstan to achieve different antenna states. [ABSTRACT FROM AUTHOR]

The incorporation of gold nanoparticles within thermally responsive poly( N-isopropyl acrylamide) hydrogels provides a simple means to define photothermally addressable materials. Relying on such composite gels, it is established here that micropatterned bilayer photoactuators demonstrate rapid and highly reversible bending and unbending behavior in response to illumination with visible light. In addition to actuation by free space light, as in most previous research on such responsive nanocomposite hydrogels, light from a 532 nm laser is also waveguided through a plastic optical fiber directly into the photoactuator, providing remotely controllable actuators that do not require line-of-sight access. [ABSTRACT FROM AUTHOR]

This paper considers a class of uncertain nonlinear systems exactly described by Takagi-Sugeno (T-S) fuzzy models, with or without matched uncertainties and/or disturbances, within an operating region in the state space. Considering the plant subject to actuator saturation is proposed, a switched control design method such that the equilibrium point of the controlled systems is locally asymptotically stable with an adequate decay rate, for all initial conditions in a region obtained in the design procedure, that is within a given operating region. Moreover, an exact representation of the minimum function using signal functions is presented. Therefore, it is offered a bridge between the switched control and variable structure control laws, because they are usually based on minimum and signal functions, respectively. Considering the well-known approximation of the signal function by a sigmoid function, this paper introduces the 'smooth minimum' function. The smooth minimum function allowed the design of 'smooth switched' control laws, without chattering, for the aforementioned class of systems. The proposed smooth switched control laws guarantee the uniform ultimate boundedness of the controlled systems. Design examples and simulation results illustrate the control design procedures and the effectiveness of the proposed control laws. Future researches in this subject may explore the presented relationship between the switched control and variable structure control laws, in order to obtain new useful control laws. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Dielectric elastomers are a type of actuator materials that exhibit excellent performance as artificial muscles, but a high driving voltage is required for their operation. By using the amazingly high output voltage generated from a triboelectric nanogenerator (TENG), a thin film dielectric elastomer actuator (DEA) can be directly driven by the contact-separation motion of TENG, demonstrating a self-powered actuation system. A TENG with a tribo surface area of 100 cm2 can induce an expansion strain of 14.5% for the DEA samples (electrode diameter of 0.6 cm) when the system works stably within the contact-separation velocity ranging from 0.1 to 10 cm s−1. Finally, two simple prototypes of an intelligent switch and a self-powered clamper based on the TENG and DEA are demonstrated. These results prove that the dielectric elastomer is an ideal material to work together with TENG and thereby the fabricated actuation system can potentially be applied to the field of electronic skin and soft robotics. [ABSTRACT FROM AUTHOR]

In the present paper, a Takagi-Sugeno (TS) model is used to simultaneously represent the behaviour of a nonlinear system and its saturated actuators. With the TS formalism and the Lyapunov approach, stabilization conditions are expressed as linear matrix inequalities for different controller designs. Static parallel distributed compensation (PDC) state feedback and static and dynamic PDC output feedback controllers for nonlinear saturated systems are proposed. The descriptor approach is used to obtain relaxed conditions to compute the controller gains. The nonlinear cart-pendulum system is used to illustrate the proposed control laws. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper studies the problem of semi-global leader-following output consensus of a multi-agent system. The output of each follower agent in the system, described by a same general linear system subject to external disturbances and actuator saturation, is to track the output of the leader, described by a linear system, which also generates disturbances as the exosystem does in the classical output regulation problem. Conditions on the agent dynamics are identified, under which a low-gain feedback-based linear state-control algorithm is constructed for each follower agent such that the output consensus is achieved when the communication topology among the agents is a digraph containing no loop, and the leader is reachable from any follower agent. We also extend the results to the non-identical disturbance case. In this case, conditions based on both the agent dynamics and the communication topology are identified, under which a low-gain feedback-based linear state-control algorithm is constructed for each follower agent such that the leader-following output consensus is achieved when the communication topology among the follower agents is a strongly connected and detailed balanced digraph, and the leader is a neighbor of at least one follower. In addition, under some further conditions on the agent dynamics, the control algorithm is adapted so as to achieve semi-global leader-following output consensus for a jointly connected undirected graph and the leader reachable from at least one follower. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Electro-mechanical valve actuators (EMVA) formed by two opposed electromagnets and two balanced springs are appealing solutions to implement advanced combustion concepts for camless engines. A crucial control problem for this valve actuator regards the first valve lift manoeuvre (termed 'first catching') to be rapidly performed after each insertion of the engine ignition key, when the EMVA rests at middle position where electromagnets offer low control authority. The control problem is challenging due to system nonlinear behavior. Mathematically, the EMVA system can be assumed to be a spring-mass impacting system affected by a non-smooth friction force and a dynamic saturated magnetic force. In this work an effective valve position-based first catching control strategy is proposed to control the strongly nonlinear system. Bifurcation analysis and parameter space simulations are used to study the closed-loop system behavior and to tune the controller gains as well. The effectiveness of the control approach is validated through numerical simulations of a highly predictive dynamic model of the valve actuator developed by authors in a previous work. [ABSTRACT FROM AUTHOR]

SUMMARY Working in extreme environments (e.g., at disaster sites) is dangerous for humans. Hence, it is important to use teleoperated robots in such extreme environments. Because heavy lifting work is involved, hydraulic actuators with high output are more commonly used than electric actuators. Therefore, it is necessary to operate remotely controlled robots driven by hydraulic actuators. Bilateral control is remote control with a sense of force. Because most bilateral control systems have been studied mainly using electric actuators, bilateral control using hydraulic actuators is still a challenge. In this study, we propose placing a bilateral controller between an electric actuator on the master side and a hydraulic actuator on the slave side using position and velocity. The controller exhibits the dynamics of bilateral control systems using position and velocity. In addition, the control performance of conventional methods and that of the proposed method are compared and experimentally verified. [ABSTRACT FROM AUTHOR]

The study discusses a model‐based fault diagnosis scheme for detection of faults in power systems. The fault models in power generating units (PGUs) and transmission and distribution networks (T&DN) have been derived in state space form. An observer‐based fault detection filter (FDF) has been used to detect these faults. Observer‐based FDF is used because of its simplicity, reliability and ease of implementation. A single machine infinite bus power system is considered wherein a synchronous generator is connected to a T&DN through a bus system. Actuator and sensor faults in PGU, and symmetric faults in T&DN have been modelled and simulated in Matlab/Simulink. The simulation results show that a fault, whenever occurs in the aforementioned parts of power systems, is detected using the knowledge of the faults models proposed in this work. [ABSTRACT FROM AUTHOR]

This paper studies the semi-global leader-following consensus problem for a group of linear systems in the presence of both actuator position and rate saturation. Each follower agent in the group is described by a general linear system subject to simultaneous actuator position and rate saturation. For each follower agent, we construct both a linear state feedback control law and a linear output feedback control law by using low gain approach. We show that semi-global leader-following consensus can be achieved by using these control laws when the communication topology among follower agents is a connected undirected graph, and the leader is a neighbor of at least one follower. Simulation results illustrate the theoretical results. [ABSTRACT FROM AUTHOR]