Design Of Actuator Research Articles

Towards Automatic Design of Soft Pneumatic Actuators: Inner Structure Design Using CNN Model and Bézier Curve-Based Genetic Algorithm

Towards Automatic Design of Soft Pneumatic Actuators: Inner Structure Design Using CNN Model and Bézier Curve-Based Genetic Algorithm

Lightweight design of piezoelectric linear displacement accumulation actuator for airfoil deployment

The electromagnetic servo steering gear commonly used in the modern small guided aircraft has parasitic electromagnetic fields that affect the navigation and guidance accuracy, and its deceleration mechanism will increase the volume and mass, and the operating temperature range of the electromagnetic steering gear is small. A recently developed piezoelectric linear displacement accumulating high-power density actuator can solve those problems effectively. A virtual prototype model of piezoelectric linear displacement accumulating high-power density actuator is established, and the reliability of the virtual prototype model is verified by comparing with the experimental data. In order to make the actuator with the lightest weight under the requirements of wing deployment, Isight and Adams co-simulation were used to optimize the parameters of the piezoelectric actuator, such as the outer diameter, length, and excitation frequency. Finally, the output power of 50.8 W/kg is achieved, which is comparable with the power density of the existing servo motor.

Performance evaluation of a walking-type piezoelectric actuator with compliant mechanism for wide-range speed driving and high-precision positioning

To achieve a wide operating velocity range, stepping without backward motion, and high positioning resolution, a walking-type piezoelectric actuator with compliant mechanisms is developed. There are few academic research reports on this type of actuator, and this paper clarifies the features and advantages of this actuator. A systematic modeling and experimental evaluation of the proposed actuator are carried out. First, the configuration of the proposed actuator and the working principle of the alternating elliptical movements of the two driving feet are described. Then, dynamic models are built to simulate the output characteristics of the proposed actuator with in-phase and opposite-phase drive, which provide guidance for the design and optimization of walking-type actuators. An actuator prototype is fabricated and experimentally evaluated. The experimental results indicate that, under the opposite-phase drive, the proposed actuator can operate at a driving frequency of 1–15000 Hz. At a frequency of 14000 Hz, a maximum velocity of 24.6 mm/s is achieved at a voltage of 36 Vpp, and the dead zone of the actuator is 0–6 Vpp. A step displacement of 2.25 μm without backward motion is accomplished at a voltage of 72 Vpp and a frequency of 1 Hz. Furthermore, the positioning resolution in the forward and reverse directions are 144 and 152 nm, respectively. The repeatability of the actuator is ±25 to ±50 nm for strokes of 325–725 nm, respectively. Therefore, compared to two driving feet being driven in phase, driving them in opposite phase as if they were walking has been confirmed to increase thrust, shorten the rise time, reduce the dead zone of driving voltage, eliminate backward motion, and provide high repeatability.

Design and development of a piezoelectric-hydraulic hybrid actuator with quarter-wavelength tubes

The piezoelectric hydraulic actuator is a hybrid device consisting of a hydraulic pump driven by a piezoelectric stack connected to a hydraulic cylinder. For this type of piezoelectric actuator, the inertial force caused by the flow pulsation of the liquid will inhibit the movement of the piezoelectric vibrator and reduce its output performance. To solve these issues, two tubes were embedded into the piezoelectric-hydraulic hybrid actuation system for the first time to act as mechanical bandstop filters by interfering with the propagation of acoustic waves. The acoustic power transmission loss of the tube is derived from the one-dimensional wave equation. According to the experimental results, when the excitation frequency is close to the optimal operating frequency corresponding to the tubes, the liquid pulsation rate is reduced, the influence of inertial force on the actuator is weakened, and the output performance is relatively significantly improved. This strategy finally leads to a maximum no-load velocity of 153.5 mm s−1 and a maximum blocking force of 261.5 N for the hybrid actuator with 300 mm tubes; the maximum no-load velocity and blocking force of the hybrid actuator with 500 mm tubes are 94.45 mm s−1 and 230 N, respectively. Furthermore, this strategy can be used in other electrohydraulic actuators to enhance their capabilities.

Design and Optimization of a Spherical Magnetorheological Actuator

Recently, an increasing number of electromagnetic devices have been using smart fluids. These include ferrofluids, electrorheological fluids, and magnetorheological (MR) fluids. In the paper, magnetorheological fluids are considered for use in a spherical actuator for haptic applications. An approach is presented to the design and optimization of such a device, using finite element method modelling linked with differential evolution (DE). Much consideration was given to the construction of the objective function to be minimized. A novel approach to objective function assembly was used, using reference values based on the model design and created with parameters set to the midpoint values of the selected range. It was found to be a useful strategy when the reference values are unknown. There were four parameters to be optimized. Three of them gravitated towards the boundary value, and the fourth (actuator radius) was somewhere in between. The value of the objective function reached a minimum in the range of actuator radius between 42.9880 mm and 45.0831 mm, which is about a 5% difference in regard to the actuator radius. Three passes of optimization were performed with similar results, proving the robustness of the algorithm.

A gradient-based approach for optimal actuator design with morphing wings

A gradient-based approach for optimal actuator design with morphing wings

Technical note: Studying lithium metaborate fluxes and extraction protocols with a new, fully automated in situ cosmogenic 14C processing system at PRIME Lab

Abstract. Extraction procedures for in situ cosmogenic 14C (in situ 14C) from quartz require quantitative isotopic yields while maintaining scrupulous isolation from atmospheric and organic 14C. These time- and labor-intensive procedures are ripe for automation; unfortunately, our original automated in situ 14C extraction and purification systems, reconfigured and retrofitted from our original systems at the University of Arizona, proved less reliable than hoped. We therefore installed a fully automated stainless-steel system (except for specific borosilicate glass or fused-silica components) incorporating more reliable valves and improved actuator designs, along with a more robust liquid nitrogen distribution system. As with earlier versions, the new system uses a degassed lithium metaborate (LiBO2) flux to dissolve the quartz sample in an ultra-high-purity oxygen atmosphere, after a lower-temperature combustion step to remove atmospheric and organic 14C. We compared single-use high-purity Al2O3 against reusable 90 %Pt / 10 %Rh (Pt/Rh) sample combustion boats. The Pt/Rh boats heat more evenly than the Al2O3, reducing procedural blank levels and variability for a given LiBO2 flux. This lower blank variability also allowed us to trace progressively increasing blanks to specific batches of fluxes from our original manufacturer. Switching to a new manufacturer returned our blanks to consistently low levels on the order of (3.4 ± 0.9) × 104 14C atoms. We also analyzed the CRONUS-A intercomparison material to investigate sensitivity of extracted 14C concentrations to the temperature and duration of the combustion and extraction steps. Results indicate that 1 h combustion steps at either 500 or 600 ∘C yield results consistent with the consensus value of Jull et al. (2015), while 2 h at 600 ∘C results in loss of ca. 9 % of the high-temperature 14C inventory. Results for 3 h extractions at temperatures ranging from 1050 to 1120 ∘C and 4.5 h at 1000 ∘C yielded similar results that agreed with the nominal value and published results from most laboratories. On the other hand, an extraction for 3 h at 1000 ∘C was judged to be incomplete due to a significantly lower measured concentration. Based on these results, our preferred technique is now combustion for 1 h at 500 ∘C followed by a 3 h extraction at 1050 ∘C. Initial analyses of the CoQtz-N intercomparison material at our lab yielded concentrations ca. 60 % lower than those of CRONUS-A, but more analyses of this material from this and other labs are clearly needed to establish a consensus value.

A controllable main wing module design and working strategy for a water-jet hybrid underwater glider

A water-jet hybrid underwater glider (WJHUG) is a hybrid-driven underwater glider (HUG) developed by Huazhong University of Science and Technology (HUST) that has a gliding mode, a fixed depth propulsion mode, and a hybrid gliding mode. However, the fixed hydrodynamic shape cannot satisfy the application requirements of the WJHUG to operate in multiple modes. To realize an actively changing hydrodynamic shape in a WJHUG, we propose a controllable main wing module (CMWM) design concept. The specific layout scheme and actuator design of the CMWM are presented. Using surrogate-based optimization (SBO), the optimization of the rectifier appendage design for the CMWM is accomplished. Analysis of the WJHUG working strategy with the CMWM is carried out by global optimization for the optimal variable wing angle under different modes. Compared with the original model, the final evaluation results show that the lift-to-drag ratio in gliding mode of the WJHUG with the CMWM was improved by a maximum of 9.4%, and the drag was decreased by a maximum of 21.5% under small angles of attack (AOAs) in fixed depth propulsion mode. Finally, the strong performance of the CMWM design and working strategy are verified by field experiments.

Design, Implementation, and Control of a Linear Electric Actuator for Educational Mechatronics

Kinematics is a fundamental topic in engineering, robotics, mechatronics, and control systems and significantly resolves some of these fields’ most pressing issues. It is essential to assess the balance between a topic’s theoretical framework and its empirical validation to succeed in engineering. Educational tools have gained significant attention for their ability to enhance the learning experience by providing the hands-on experiences necessary to assess theoretical frameworks and empirical validations. This paper presents a system incorporating state-of-the-art features, including a fuzzy controller enabling precise control of a linear actuator and a USB camera, to provide an interactive experience. The USB camera captures the position of the actuator, providing real-time visual feedback and allowing the students to validate their theoretical understanding through practical experiments. Precision, accuracy, resolution, and the implementation of the fuzzy controller are measured to evaluate the whole system’s performance. The design, implementation, and control of our educational electrical linear actuator for teaching kinematics concepts contribute to a practical educational tool and advance interactive learning approaches in the field.

Shape-Programmable Liquid-Crystalline Polyurethane-Based Multimode Actuators Triggered by Light-Driven Molecular Motors.

In recent years, light-driven soft actuators have been rapidly developed as enablers in the fabrication of artificial robots and biomimetic devices. However, it remains challenging to amplify molecular isomerization to multiple modes of macroscopic actuation with large amplitude and complex motions. Here, a strategy is reported to build a light-responsive liquid-crystalline polyurethane elastomer by phototriggered overcrowded alkene-based molecular motors. A trifunctional molecular motor modified with an ethylene glycol spacer on the rotor and stator functions as a crosslinker and unidirectional stirrer that amplifies molecular motion into macroscopic movement. The shape-programmable polymeric film presents superior mechanical properties and characteristic shape-memory effect. Furthermore, diverse modes of motions including bending, unwinding, and contracting with tunable actuation speed over a wide range are achieved. Such research is hoped to pave a new way for the design of advanced light-responsive soft actuators and robots.

Design and Characteristics of Shape Memory Alloy Bidirectional Torsional Actuator

To overcome the problems of the low power/weight ratio of traditional servo motors, complex transmission systems, and large space occupied by hydraulic drive systems, this paper designs a bidirectional torsional actuator using the shape memory effect of Ti-Ni shape memory alloy (SMA) wire, which aims to realize the folding and unfolding of the wings of flying cars. The model of the designed actuator was established and the theoretical calculation was analyzed, based on which the experimental verification was carried out. It is found that when the heating current is 1.6 A, the mechanism can take into account the economy under the premise of meeting a certain folding speed. When the pre-stretching amount of SMA wire is 3%, the residual strain corresponding to the wire is small, about 0.577%, and it can provide driving torque and torsion angle to meet the design requirements of the actuator. This verifies the feasibility of the actuator and obtains the driving characteristics of the actuator. Finally, the shortcomings and improvement measures of the actuator are analyzed briefly.

Achieving Significant Burst Motion Based on Epicycloid Induction Principle for Stick–Slip Piezoelectric Actuator

The burst motion as a potential motion is discovered in recent years and has important effects on the output performance of the piezoelectric actuator. How to induce the burst motion has become a research hotspot and a current challenge in the field of piezoelectric actuator. To eliminate the backward motion and induce significant burst motion, an epicycloid induction principle (EIP) was proposed in this paper. Correspondingly, a stick-slip piezoelectric actuator with a special dual feet compliant mechanism (DFCM) was designed, and the corresponding prototype was fabricated to verify the EIP. Under the excitation of square wave signals, the driving and clamping feet alternately pushed the bearing, and the epicycloid motion of the bearing induced the burst motion of the slider. The threshold voltage about the clamping foot of the prototype with no backward motion was set through the pre-experiment. At this voltage, the displacement-time curves in one period showed three consecutive steps, which confirmed the feasibility of the EIP. In addition, the prototype has the resolution of 160 nm and the vertical loading capacity greater than 5 N. The proposed EIP is effective for inducing significant burst motion and offers a novel idea for the structure design of the stick-slip actuators.

A single actuator vs. multi-actuator design of an input-feedback control for the generalized Kuramoto–Sivashinsky equation

A single actuator vs. multi-actuator design of an input-feedback control for the generalized Kuramoto–Sivashinsky equation

Design and characterization of electro-active soft actuator based on phase transition of microencapsulated silicon-ethanol composite

In this study, we demonstrate the development of a fast-response soft composite actuator fabricated by mechanical mixing of silicone elastomer (matrix) and ethanol (as phase-change fluid). Joule heating generated by electrical actuation causes a liquid-vapor transition of ethanol embedded in silicone microcapsules; provides the required pressure for mimicking the natural movements. We discuss the critical design variables to improve the temperature response, chemical composition, mechanical properties, force generated, and microstructure of soft actuator. Our soft actuator produces a high load-to-weight ratio (1000 times greater than its own) using a low-voltage source (˂20V). The stability of the soft actuator under multiple working cycles would bring the application to different robotic areas. The actuator using the mechanism presented here is easy to manufacture, automate, and recyclable. It can be used in a range of robotic applications.

Influence of temperature on the SMA-PDMS interfacial bond behavior and its modeling with temperature dependent trapezoidal cohesive law

Soft actuators composed of shape memory alloy (SMA) wires embedded in polydimethylsiloxane (PDMS) matrix are potential in shape-morphing structures and soft robots. However, the SMA-PDMS interface is inevitably subjected to high temperatures during actuation due to Joule heating of the SMA, which affects its bond properties. However, knowledge of how temperature impacts SMA-PDMS interfacial bond properties is still insufficient. This paper conducted fiber pull-out experiments at various interface temperatures to monitor and trace the debonding process with high-speed camera. Results show that the maximum debonding load, critical debonding displacement, and friction load are in exponential decay with interface temperature. Notably, interfacial strength degradation exceeds 50 % when the interface temperature increases from 25 °C to 100 °C, and the traction-separation behavior of SMA-PDMS interface shifts from trapezoidal to triangular as the interface temperature increases. A finite element model was developed to simulate the debonding behavior of SMA-PDMS, in which the interface was modeled using the cohesive zone model with temperature-dependent trapezoidal constitutive law. Simulation results agree well with experiments. Stress distribution during the interface debonding process was also analyzed and discussed. The work demonstrates the importance of accounting for interface bond strength degradation caused by temperature in the design of SMA-PDMS soft actuators.

Analytical input-output modelling of surface dielectric barrier discharge plasma actuator

Surface dielectric barrier discharge (SDBD) actuators are a type of asymmetric dielectric barrier discharge (DBD) actuator that can be used to generate ions and produce thrust for near-space vehicles. In this paper, a physics-based model for SDBD produced thrust is developed that accounts for geometric and environmental variation between SDBDs. The presented SDBD analytical model (SDBD-AM) is based on models for parallel-plate DBDs but accounts for the ‘virtual electrode’ resulting from changing plasma length that is particular to SDBDs. To validate the model, thrust measurements from 12 different configurations from previous studies were used, and the mean absolute percentage error (MAPE) between each configuration and SDBD-AM was determined. The observed effects on the model were attributed to structural effects including electrode width, electrode spacing, dielectric, and environmental effects including pressure, and the apparent uncertainties are different for each effect. As a result, it was obtained that the MAPE between SDBD-AM and the experimental data for different structures is 11%, and for different pressures, it is 12%. The body force field has been simulated using SDBD-AM and a distribution function in COMSOL software, and the body force profile near the exposed electrode has been validated with a previous numerical model. This model can be used for the design and optimization of SDBD actuators and also in the design of control systems such as spacecraft attitude control in order to increase the accuracy and performance of the controller.

Aeroelastic Analysis of Actuated Adaptive Wingtips Based on Pressure Actuation

Folding wingtips address the challenges posed by high-aspect-ratio wings, such as airport conformity and increased wing root bending moment. Actuated adaptive wingtips extend the functionalities of folding wingtips by using a stiffness-adaptive aeroelastic hinge that is actively adjustable in flight. The objective of this paper is the aeroelastic analysis of a wing equipped with an adaptive-stiffness hinge. While the structural design of the wingtip actuator based on pressure-actuated cellular structures (PACS) was developed in a previous study, in this study the authors verify the concept of actuated adaptive wingtips through aeroelastic analysis. This study shows that the investigated PACS actuator, structurally designed from glass-fiber-reinforced plastic, is capable of bearing the loads acting on the wingtips of a Cessna Citation X. The adaptive-stiffness hinge, positioned between 86.7 and 91.2% of the semispan, reduces the wing root bending moment by up to 7.8% in a 2.5g maneuver load case, while keeping the wing straight in cruise. A further increase in load alleviation potential can be achieved in the future by extending the actuator’s operating envelope and thus increasing its load-bearing capacity. The functional verification of the actuated adaptive wingtip concept by means of aeroelastic analysis forms the basis for the manufacturing and testing of a functional prototype.

Design and performance evaluation of a noncontact rotation actuator driven by near-field ultrasonic energy

The innovation of novel drive methods based on smart materials is an important way to promote the development of machines and equipment to the direction of high speed, high efficiency, clean and intelligence. Based on the piezoelectric drive principle and near-field acoustic levitation (NFAL) technology, a noncontact rotation actuator is proposed driven by ultrasonic energy. Under the action of ultrasonic energy generated by the ultrasonic emitter, the object can be stably levitated and driven to rotate at a certain speed. The electroacoustic conversion structure of the actuator is designed and its performance parameters are predicted. To verify the levitation and driving performance, a testing system for the actuator is developed. The structural and dynamic parameters’ influence on the rotor motion are investigated by experimental means, and the optimal parameter combination is acquired. The experiment results show that the maximum driving speed of the optimized rotor can reach 3145 rpm and the maximum noncontact driving torque is about 1.24 mNm under the excitation frequency of 20.21 kHz and the excitation voltage of 225 Vp-p. The proposed levitating drive method based on ultrasonic energy is expected to show great potential in the field of noncontact operation or actuation.

Dynamic Suspension Utilizing PID Control with MATLAB

This research paper proposes a PID controlled electromagnetic actuator design for active suspension system. In this method the ride profile is an unknown disturbance and we only measure the vertical displacement of the vehicle body caused by irregular ride profile. The simulation result show that proposed control can achieve better suspension performance and requires less information, also achieves better traction after encountering irregularities on the road.

Methodology for Preliminary Flight Control Actuator Design

In this paper, a methodology for the preliminary design of decentralized civil-use flight control actuators is presented that is able to perform the calculations with a very small amount of input data. This enables the user to achieve good actuator key characteristics regarding the weight, power, and volume in the preliminary aircraft design stage without the need for an empirical database. Optionally adjustable setting parameters of the individual components allow the component design to be customized in detail. Both electromechanical and electrohydrostatic actuators are considered. The methodology presented here aims at sizing each individual component of the actuators in terms of volume, mass, and power consumption. The components are broken down into simple geometric shapes where possible. The methodology is evaluated on several actuators of different performance and weight classes from 3.2 kg up to 66.9 kg and provides more accurate results than other common approaches, which is suitable in the preliminary aircraft design stage.