Characteristics Of Actuator Research Articles

Study on Multi-flow Field Characteristics of Unloading Groove Spacing of Bidirectional Gear Pump

Improving the output flow quality of the high-precision micro bidirectional gear pump can effectively improve the position control accuracy and dynamic characteristics of the electro-hydraulic actuator. In order to meet the appeal requirements and reduce the vibration and noise of the gear pump and prolong its working life, this paper starts with the research of the key part of the gear pump–the unloading groove structure. The three characteristics of trapped oil phenomenon, cavitation phenomenon, and flow were used as key indices to evaluate gear pump performance. Using numerical simulation analysis, the dynamic grid simulation method was used to explore the influence of unloading groove spacing on the transient multi-flow field characteristics of the gear pump under conventional design range. Our results show that reducing the distance between unloading grooves can greatly reduce the trapped oil pressure and the amount of gas precipitation in the flow field, while reducing flow pulsation and improving volumetric efficiency. However, when the unloading groove spacing is too small, the instantaneous flow curve loses the pulsation characteristics and the flow stability decreases. Considering the influence of the gear pump on the accuracy of the electro-hydraulic actuator and the performance of the gear pump itself, the analytic hierarchy process was used to obtain the 1 mm unloading slot spacing, which best meets the engineering requirements of high flow accuracy and low vibration noise. The results provide a basis for work on the structural optimization of high-precision micro gear pumps.

Integrated Pressure Estimation and Control for Electro-hydraulic Brake Systems of Electric Vehicles Considering Actuator Characteristics and Vehicle Longitudinal Dynamics

In the automotive field, electro-hydraulic brake systems (EHB) has been developed to take place of the vacuum booster, having the advantage of faster pressure built-up and continuously pressure regulation. Pressure control, one of the most crucial issues to be solved for EHB, is influenced by the system nonlinearities (e.g., pressure-position, friction). Recently, there are a series of studies that focus on this issue. However, the pressure control based on pressure estimation is rarely investigated in the previous literatures. In order to achieve cost-effective and highly integrated, the pressure is regulated without any add-in sensors, making it very difficult to achieve a satisfactory performance. A pressure control system based on pressure joint estimation is developed in this article according to a requirement-oriented model. The pressure joint estimation is designed considering actuator characteristics and vehicle dynamics. The wheel speed feedback is used for modification via a proportional-integral observer. A pressure control combining feedforward, torque-adaptive friction compensation with feedback controller is employed to improve the pressure-tracking performance. The constraint of feedback gain of controller is derived based on the small-gain theorem to remain the input–output stability of the overall control system. Superior to the estimation method based on actuator characteristics, the joint estimation method improves the accuracy by more than 10%. The pressure-tracking performance and robustness of system are validated by vehicle experiments under the typical common braking situations.

Effects of effective voltages, electrode types and stretching states on electrical properties and actuation characteristics of dielectric elastomer materials

In this study, the electrical properties of DE materials were systematically tested, and the effects of different effective voltages, electrode types and stretching states on permittivity, dielectric loss, conductivity, capacitance and electrical efficiency were discussed. The frequency dependence of the electric dipole in the material is revealed from the microscopic point of view. Finally, based on the structure and volume incompressibility of the DE, the actuation coefficient of the DE is proposed to characterize its deformation effect. The results show that the permittivity of the DE is very sensitive at high frequency, especially for DE materials with carbon electrode and gold-carbon electrode. At the same effective voltage and gold electrode, the permittivity decreases with the increase of equal biaxial stretching. For the same stretching area, the permittivity of equal biaxial stretching is larger than that of unequal biaxial stretching. The DE with carbon electrode has the largest dielectric loss and is easy to be destroyed in engineering application, which needs further optimization. The dielectric loss decreases with the increase of equal biaxial stretching, which is mainly due to the decrease of orientation deviation between main chain and side chain in DE material. The electric efficiency at low frequency is generally higher than that at high frequency, and the highest electric efficiency can reach 99.64%. With the increase of frequency, the actuation deformation coefficient decreases rapidly. This work will further promote the development of DE materials used in soft robot, and provide a theoretical reference for the design of actuators and sensors.

Modeling and control of rate-dependent hysteresis characteristics of piezoelectric actuators based on analog filters

The hysteresis nonlinearity and rate dependence of piezoelectric actuators seriously affect their positioning accuracy in precise positioning. Proper compensation needs to be given to improve the positioning accuracy of the actuator. In this paper, the static hysteresis characteristics are described by improving the BP neural network model based on the adaptive particle swarm optimization algorithm, and the PI model is used as the hysteresis factor by the extended space method to realize the multi-valued mapping of hysteresis nonlinearity. And input three types of voltage signals, compare and analyze the experimental data and model prediction output, and use the maximum relative error and root mean square error as the evaluation indicators to prove the accuracy of the built model. Based on the improved BP neural network model, a second-order low-pass analog filter is introduced to construct a rate-dependent hysteresis model. Comparing and analyzing the rate-dependent hysteresis model and the static hysteresis model, the experimental results show that when the signal frequency is 10 Hz, 40 Hz, and 100 Hz, the predicted output of the rate-dependent hysteresis model is compared with that of the static hysteresis model, and the root mean square error decreases by 46.3%. %, 59.6%, and 65.1%, the model can more accurately describe the hysteresis characteristics of piezoelectric actuators. Finally, a rate-dependent hysteresis inverse model is established, and the rate-dependent hysteresis inverse model is used as a feedforward combined with a single neuron network PID control to form a composite controller, and the experimental verification is carried out. The results show that the maximum error between the composite controller and the actual expectation is only 2.15%. Therefore, the established model can accurately express the rate-dependent hysteresis characteristics of piezoelectric actuators, and the use of a composite controller can effectively reduce the accuracy error caused by the hysteresis nonlinear characteristics of piezoelectric actuators.

Humidity‐Driven High‐Performance Electrothermal Actuation of Vertically Stacked 2D PtTe2 Layers/Cellulose Nanofibers

A new type of soft actuators based on a vertical stack of nanoporous 2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐oxidized cellulose nanofibers (TOCNs) and atomically thin 2D platinum ditelluride (PtTe2) layers is reported. The actuation of TOCNs is driven by the interfacing 2D PtTe2 layers whose electrothermal proficiency precisely controls their hydration/dehydration states sensitive to mechanical deformation. These vertically stacked TOCN/2D PtTe2 actuators present excellent actuation characteristics such as high linearity of bending curvature versus applied voltage and well‐preserved reversibility during cyclic operations. Most notably, they exhibit an extremely large weight‐lifting ratio, i.e., ≈1000 times the mass of the TOCN layers, confirming superior mechanical robustness. Furthermore, complicated actuations such as twisting in a 3D manner are demonstrated by judiciously controlling the surface wettability of TOCN layers. This study unveils opportunities for CNFs and 2D materials for actuator applications, as well as suggests new design strategies broadly applicable to soft robotics and biomimetic devices.

Modeling and Characterization of Tensegrity Structures Integrating Dielectric Elastomer Actuators

Tensegrity structures, architectures that consist of elastic cables and rigid rods, have attracted attention as a building block of robots because of their compliance, lightweight properties, and mechanical robustness. This article describes a method to create electroactive tensegrity structures that employs a dielectric elastomer actuator (DEA) as the actuation principle. Two different types of DEA‐tensegrities are considered herein: a membrane type and a cable type. In these devices, DEAs are made of an acrylic elastomer (3 m, VHB 4905) and a stretchable conductive film (Adhesives Research, ARcare 90336) used as dielectric and electrode layers, respectively. An analytical model of DEA‐tensegrities is built that guides the fabrication of experimental devices. The fabricated DEA‐tensegrities are characterized by the actuation strain in the height direction. As a result, voltage‐controlled actuation strains of 7.5% and 2.0% are observed at 10 kV for membrane type and cable type DEA‐tensegrity, respectively, while the model prediction captures the actuation characteristics.

Mean model of the dielectric barrier discharge plasma actuator including photoionization

A numerical algorithm is proposed for simulation of the dielectric barrier discharge plasma actuators including photo-ionization. The computational bottleneck related to a very long computing time has been circumvented by suppressing the discharge pulses and proposing a mean discharge model. It incorporates an artificial damping term into the electron transport equation to suppress the formation of pulses, which significantly accelerates the simulation. Based on the fluid description of three generic species: electrons, positive and negative ions, the model accounts for the drift, diffusion, and reaction terms. The reaction coefficients are extracted from the Boltzmann equation considering the local field approximation. A self-sustained discharge is achieved by including photo-ionization during the positive voltage phase, and the secondary electron emission from the metal surface, during the negative voltage phase. The proposed methodology compromises the computational burdens of the first-principle approaches and inadequacy of the simplistic models in incorporating the problem physics. The accuracy of the proposed methodology has been validated by comparing the computational and experimental data for the electrical and flow characteristics of a laboratory actuator.

Event-triggered adaptive control of hypersonic vehicles subject to actuator nonlinearities

This paper investigates the event-triggered adaptive control problem for air-breathing hypersonic vehicles (AHVs) subject to physical actuator nonlinearities. In contrast with abundant AHV control strategies belonging to the traditional sample-data framework, the presented adaptive control works with an event-triggered mechanism, which naturally reduces the executing frequency of scramjet fuel-to-air equivalency ratio (FER) and aerodynamic control surface (ACS). During the event-triggered controller design, practical actuator characteristics including magnitude-rate composite constraints and servo transient dynamics are synthetically considered. In the velocity loop, the built-in FER saturation, which is a fusion of physical FER magnitude and rate constraints, is handled by reshaping the velocity reference with the help of an adaptive reference governor. Meanwhile in the altitude loop, a neural control allocator directly generates feasible ACS commands via a neural network that is well trained by means of the optimal control allocation. As the result, ACS magnitude-rate composite constraints and servo transient dynamics can be accommodated without implementing any time-consuming optimization searching process. Theoretical analysis indicates the guaranteed closed-loop stability and tracking performance while excluding the undesired Zeno behavior. Simulations validate the effectiveness of the proposed event-triggered adaptive control.

Control of Inchworm Driven by Strain Characteristics of Piezoelectric Actuator

Control of Inchworm Driven by Strain Characteristics of Piezoelectric Actuator

Research on impedance network modeling and output characteristics of magnetostrictive electro-hydraulic actuator

Research on impedance network modeling and output characteristics of magnetostrictive electro-hydraulic actuator

An Inchworm and Stick-Slip Dual Mode Piezoelectric Linear Actuator for Cell Injection

Cell injection system for biomedical engineering demands that actuators have large stroke, high resolution and speed for cell positioning and injection. Single mode piezoelectric actuators could meet some of these requirements but hardly all. Stick-slip actuator is easy to achieve high-speed operation, but it is prone to setback; The speed characteristics of the inchworm actuator are lower than those of the stick-slip actuator, but the step is more stable and the setback is lower. This study proposes an inchworm and stick-slip dual mode piezoelectric actuator (ISSPA) for cell injection. It integrates two working modes into one actuator and both modes drive the same slider. The stick-slip mode works at high frequency for fast positioning to the cell and the inchworm mode drives the needle to puncture the cell membrane and accurately locates to the specified location. The structure and working principle of the ISSPA are provided. A prototype of the proposed ISSPA is fabricated and experiments are conducted. When the driving voltage of the piezoelectric stack is 100 V and the frequency is 500 Hz,the maximum speed of the ISSPA is 2.287 mm/s in the stick-slip mode. When the driving voltage of the piezoelectric stack is 60 V, the frequency is 3 Hz and the load is 0.5 kg,the minimum step displacement is 57 nm in inchworm mode. Demonstration of cell injection is carried out by using the ISSPA to positioning and puncturing a zebrafish embryo. Fast positioning with the stick-slip mode and accurate puncture with the inchworm mode are achieved with the ISSPA alone, taking 12 seconds for the whole injection process. It could be expected to apply the ISSPA to cells with wide range of diameter, as the frequency of the stick-slick mode and the voltage of the inchworm mode could be well regulated.

Flow control performance evaluation of a tri-electrode sliding discharge plasma actuator

Tri-electrode sliding discharge (TED) plasma actuators are formed by adding a direct current (DC) exposed electrode to conventional dielectric barrier discharge (DBD) plasma actuators. There are three TED modes depending on the polarity and amplitude of the DC supply: DBD discharge, extended discharge and sliding discharge. This paper evaluates the electrical, aerodynamic and mechanical characteristics of a TED plasma actuator based on energy analysis, particle image velocimetry experiments and calculations using the Navier–Stokes equation. The flow control performances of different discharge modes are quantitatively analyzed based on characteristic parameters. The results show that flow control performance in both extended discharge and sliding discharge is more significant than that of DBD, mainly because of the significantly higher (up to 141%) body force of TED compared with DBD. However, conductivity loss is the primary power loss caused by the DC polarity for TED discharge. Therefore, power consumption can be reduced by optimizing the dielectric material and thickness, thus improving the flow control performance of plasma actuators.

Jet Velocity and Acoustic Excitation Characteristics of a Synthetic Jet Actuator

The effect of the excitation frequency of synthetic jet actuators on the mean jet velocity issuing from an array of circular orifices is investigated experimentally, focusing on the acoustic excitation characteristics of the actuator’s cavity. Two cavity configurations are considered. In the first configuration, synthetic jets are generated by exciting a single, large cavity having an array of sixteen orifices via sixteen piezoelectric elements. In the second configuration, the cavity volume of the first configuration is divided into eight isolated compartments, each with two orifices and two piezoelectric elements. Several distinct resonant peaks were observed in the frequency response of the synthetic jet actuator built with a single large-aspect-ratio cavity, whereas the case of compartmentalised cavities exhibited a single resonant peak. Acoustic simulations of the large-aspect-ratio-cavity volume showed that the multiple peaks in its frequency response correspond to the acoustic standing-wave mode shapes of the cavity. Due to its large aspect ratio, several acoustic mode shapes coexist in the excitation frequency range aside from the Helmholtz resonance frequency. When the actuator’s cavity volume is compartmentalised, only the Helmholtz resonance frequency is observed within the excitation frequency range.

Characteristics Analysis of an Electromagnetic Actuator for Magnetic Levitation Transportation

In this article, an electromagnetic actuator is proposed to improve the driving performance of magnetic levitation transportation applied to ultra-clean manufacturing. The electromagnetic actuator mainly includes the stator with the Halbach array and the mover with a symmetrical structure. First, the actuator principle and structure are illustrated. Afterward, in order to select a suitable secondary structure and analyze the characteristics of the actuator, the electromagnetic characteristics of actuators with different secondary structures are analyzed by the finite element method (FEM). Analysis results show that the actuator adopting the secondary structure with a Halbach array will increase the electromagnetic force and working stability. The secondary with the three-section Halbach array is selected for the electromagnetic actuator. Then, the influence of secondary permanent magnet (PM) thickness on the electromagnetic force is analyzed by FEM. The results indicate that the increase in PM thickness will lead to increased electromagnetic force and decreased utilization ratio of PM. Finally, a prototype of an electromagnetic actuator is built, and experiments are implemented. The correctness of the theoretical analysis and the effectiveness of the electromagnetic actuator are verified by experimental results.

Silicon Distribution-Induced Actuation Film with Bidirectional Bending Deformation and Versatile Bionic Applications.

As an important branch of intelligent materials, the research and development of stimulus-responsive flexible intelligent actuation materials is of great significance to promote the industrialization of intelligent materials. In this study, the asymmetric PVA-co-PE/silicon nanoparticle (PPSN) composite films and PVA-co-PE/silicon sol (PPSS) composite film with different silicon distributions were prepared by a simple spraying method. The silicon nanoparticle layer in the PPSN composite film was similar to the sand-like water-absorbing layer, which can quickly absorb water and permeate it into the interior region, leading to the hygroscopic expansion behavior on one side of the nanofiber film. Then, the PPSN composite film would quickly bend and deform to the silicon nanoparticle side. However, in the PPSS composite film, due to the excellent hygroscopicity and swelling characteristics of the silica sol layer, the composite film can be rapidly deformed to the PVA-co-PE nanofiber film side under moisture stimulation. The above results subvert the traditional asymmetric actuation film, which mainly depends on the hydrophilicity difference to determine the hygroscopic responsiveness and deformation direction, and ignore that the swelling degree is the main factor determining the bending direction of actuator. In addition, both the composite films can quickly respond to moisture stimulation (<1 s) and produce large-scale bending deformation (180°). Furthermore, due to the excellent interface adhesion formed by the continuity structure in the PPSS composite film, it has better actuation stability than the PPSN composite film. The excellent actuation characteristics and different bending directions of the PPSN and PPSS composite films make it a great application prospect in the field of bionics in the future.

Aluminum/Bromate and Aluminum/Iodate Mechanically Rechargeable Batteries

The ever-increasing characteristics of microcomputers, sensors, actuators, and communication systems require more powerful and more compact autonomous power sources. Al/bromate and Al/iodate flow batteries are proposed as new power supply units for use in oxygen-deficient environments. The batteries employ a mechanically rechargeable aluminum anode flooded with aqueous salt electrolytes or seawater, a cation-exchange membrane, and a carbonaceous porous cathode, where acidified alkali metal bromate, or iodate, is reduced in a six-electron process. The theoretical energy density of an Al/bromate flow cell per reactants is 0.65 kWh kg−1. Seawater is assumed as an electrolyte for the anode compartment. Using a H2/iodate flow cell, it is shown that iodate–iodine–iodide electrochemical transformations can be realized in both directions in acidic media at carbonaceous electrodes. At 30 °C, the area-specific power of the single cells of the Al/bromate and Al/iodate flow batteries reaches 0.26 W cm−2 and 0.075 W cm−2, respectively.

Preface

The 2022 International Conference on Electronics Technology and Artificial Intelligence (ETAI 2022) was successfully held on September 23rd-25th, 2022 in Chongqing, China (online conference). ETAI 2022 promoted scientific innovation, expanded channels of international academic exchange in science and technology, boosted the development of the Greater Bay Area, and strengthened academic cooperation between China and the outside world.In the conference, we were greatly honored to have Prof. Zhikui Chen from Dalian University of Technology, China to serve as our Conference General Chair. The conference was composed of keynote speeches, oral presentations and online Q&A discussion, attracting 100 delegates worldwide. Firstly, the keynote speakers were each allocated 30-45 minutes to address their speeches. Then in the next part, oral presentations, the excellent papers we had selected were presented by their authors one by one.Four distinguished professors were invited to hold keynote speeches during the conference. Primarily, Prof. Ning Sun from Nankai University, China performed a keynote speech on Modeling, Dynamics, and Intelligent Control of Complicated Underactuated Cranes: Theory and Experiments. And then, Prof. Huajun Dong from Dalian Jiaotong University, China made a report on the title Researches on Characteristics of Vacuum Switching Arc and Actuator. Moreover, Assoc. Prof. Guanglei Wu from Dalian University of Technology, China reported on Path Planning of Industrial Robots for Obstacle Avoidance. Last but not the least, Prof. Bhanu Prakash Kolla from K L University, India shared with us his research: Quantum Computing. All of them combined their own research areas with the conference theme to make dramatic keynote speeches, which triggered heated discussion in the conference. Every participant praised this conference for disseminating insightful knowledge.We are glad to share with you that we’ve selected a bunch of high-quality papers from the submissions and compiled them into the proceedings after rigorously reviewing them. These papers feature but are not limited to the following topics: Electronic Signals, Advanced Electromagnetics, Intelligent Automation, Fuzzy Logic, etc. All the papers have been checked through rigorous review and processes to meet the requirements of publication.We would like to acknowledge all of those who supported ETAI 2022 and made it a great success. In particular, we would like to thank the Journal of Physics: Conference Series, for the hard work of all its colleagues in publishing this paper volume. We sincerely hope that ETAI 2022 turned out to be a forum for excellent discussions that enable new ideas to come about, promoting collaborative research.The Committee of ETAI 2022List of Committee member is available in this Pdf.

Evolution of a single sessile droplet under the influence of the dielectric barrier discharge plasma actuator

Ice accretion on airplane surfaces has been widely recognized as a significant safety threat, and corresponding investigations of anti-/de-icing technologies have experienced tremendous growth during the last two decades. Dielectric barrier discharge plasma actuators involve different characteristics, such as thermal, acoustic, and flow characteristics, which are well suited for reducing and preventing ice accretion on wing surfaces effectively and safely. However, the correlation between the droplet, as the core of ice formation, and the plasma actuator is still not very clear. In order to understand the anti-/de-icing mechanism of the plasma actuator further, the evolution of a single sessile droplet under the influence of a symmetrical plasma actuator is studied. Interestingly, the oscillation of the droplet is first observed on the initiation of the plasma actuator, which is quite different from the droplet variation under traditional heating or cooling. Then, the flow field inside the droplet under the effect of the induced flow field of the plasma actuator is first uncovered by using the particle image velocimetry system. Subsequently, the evolution process of droplet deformation, deformed droplet moving downstream, deformed droplet moving downstream and evaporating, and water film moving downstream and evaporating is revealed. In addition, the underlying mechanism of the evolution process of the droplet is discussed based on the different characteristics of the plasma actuator. This study provides an in-depth understanding of the correlation between the droplet and the plasma actuation and lay a foundation for proposing the optimized strategy of anti-/de-icing using plasma actuators.

Plasma kernel model and energy transformation characteristic of plasma synthetic jet actuator

This article conducted a theoretical, experimental, and numerical investigation to clarify the plasma kernel model and energy transformation characteristics of the plasma synthetic jet actuator (PSJA). Plasma kernel and blast wave theory were used to describe the formation and evolution of the arc-discharge energy deposition process and build a plasma kernel model. Schlieren experiment visualized the formation and evolution of the synthetic jet flow and used it as a validation of the numerical simulation. Five plasma synthetic jet actuators with different cavity volumes (128–512 mm3) and different discharge energy (2.8–11.3 mJ) were modeled numerically to investigate the energy transformation characteristic of PSJA. Results showed that plasma kernel radius and formation time could be theoretically predicted with specific deposition energy and correspond well with simulation results. The peak pressure and temperature rise in the cavity can also be calculated. Moreover, the proportion of kinetic energy increases linearly with non-dimensional deposition energy, while potential energy has a reverse tendency with non-dimensional cavity volume and deposition energy.

Study of the influence of current pulse parameters on kinematic and energy characteristics of a plasma actuator based on a moving electric arc

In this work, a parametric study of the flow induced during the movement of an arc channel in a transverse constant magnetic field in initially still air is carried out. The analysis of the flow structure, integral energy and kinematic characteristics of the arc acceleration process is carried out. Instantaneous velocity fields in the induced flow were experimentally obtained for the range of discharge current amplitudes from 8 to 160 A and pulse durations from 40 to 380 μs. A parametric study of the flow structure in the wake behind the arc is carried out by the method of two-dimensional numerical simulation in the MHD approximation. In the particular case of a single-mode current pulse, the shape of the current pulse is optimized to maximize the gas momentum in the near-wall region. It is shown that similar conditions for the balance of local acceleration, convective acceleration and viscous forces are observed for the problem of flow past an arc and a cylinder for regimes with a conditionally steady vortex shedding in the wake. In this case, the coincidence of the vortex shedding frequency occurs when the characteristic scale of the streamlined body is chosen equal to half the height of the thermal cavity.