In this work, we proposed a control moment generator, which is called Trailing Edge Change (TEC) mechanism, for attitudes change in hovering insect-like tailless flapping-wing MAV. The control moment generator was installed to the flapping-wing mechanism to manipulate the wing kinematics by adjusting the wing roots location symmetrically or asymmetrically. As a result, the mean aerodynamic force center of each wing is relocated and control moments are generated. The three-dimensional wing kinematics captured by three synchronized high-speed cameras showed that the flapping-wing MAV can properly modify the wing kinematics. In addition, a series of experiments were performed using a multi-axis load cell to evaluate the forces and moments generation. The measurement demonstrated that the TEC mechanism produced reasonable amounts of pitch, roll and yaw moments by shifting position of the trailing edges at the wing roots of the flapping-wing MAV.
As an effort to explore the potential implementation of wing feather separation and lead-lagging motion to a flapping
wing, a biomimetic flapper with separable outer wings has been designed and demonstrated. The artificial wing feather
separation is implemented to the biomimetic wing by dividing the wing into inner and outer wings. The features of
flapping, lead-lagging and feather separation of the flapper are captured by a high-speed camera for evaluation. The
performance of the biomimetic flapper with separable outer wings is compared with that of a flapper with inseparable
outer wings in terms of lift and thrust production. For low flapping frequency ranging from 2.47 Hz to 3.90 Hz, the biomimetic flapper shows higher thrust and lift generation capability, which is demonstrated from a series of experiments. The experiments show that the outer parts of the separable wing are able to deform largely resulting smaller amount of drag production during upstroke, while still producing relatively larger lift and thrust during downstroke.
This paper presents a concept of a fish robot actuated by an SMA-based actuator. The bending-type actuator system is
composed of a 0.1mm diameter SMA wire and a 0.5mm thick glass/epoxy strip. The SMA wire is installed to the bent
composite strip. The actuator can produce about 200gf of blocking force and 3.5mm displacement at the center of the glass/epoxy strip. The bending motion of the actuator is converted into the tail-beat motion of a fish robot through a linkage system. The fish robot is evaluated by measuring the tail-beat angle, swimming speed and thrust produced by the fish robot. The tail-beat angle is about 20° and the maximum swimming speed is about 1.6cm/s. The measured thrust is about 0.4gf when the fish robot is operated at 0.9Hz.
The purpose of this study is improvement of a fish robot actuated by four light-weight piezocomposite actuators
(LIPCAs). In the fish robot, we developed a new actuation mechanism working without any gear and thus the actuation
mechanism was simple in fabrication. By using the new actuation mechanism, cross section of the fish robot became 30%
smaller than that of the previous model. Performance tests of the fish robot in water were carried out to measure tail-beat
angle, thrust force, swimming speed and turning radius for tail-beat frequencies from 1Hz to 5Hz. The maximum swimming
speed of the fish robot was 7.7 cm/s at 3.9Hz tail-beat frequency. Turning experiment showed that swimming direction
of the fish robot could be controlled with 0.41 m turning radius by controlling tail-beat angle.
This paper describes an approach to increase the flapping frequency of a previously developed flapper actuated by Lightweight Piezo-
Composite Actuator (LIPCA) to mimic the flapping frequency of Allomyrina Dichotoma of which flapping frequency is typically
30Hz. To achieve this purpose, the dynamic characteristics of the LIPCA and modification of a four-bar linkage have been studied.
The parametric study showed that an appropriate combination of linkage lengths can provide a better moment transmission for a given
flapping angle amplification, thus the flapping frequency could be increased. A newly designed four-bar linkage system was
fabricated based on the parametric study and then tested to verify the possibility. The test results showed that the optimal flapping
frequency of the modified flapper was measured to be about 15 Hz, which is about 50% increases compared to that of the previous
flapper. The modified flapper could also produce 3.02 gram force in vertical direction with 97 degree of flapping angle at the optimal
frequency.
KEYWORDS: Digital image correlation, Scanning electron microscopy, Electron microscopes, Veins, Cameras, 3D metrology, Natural surfaces, Composites, 3D image processing, CCD cameras
In the present study, a digital image correlation method has been applied to measure the elastic modulus of a beetle wing
membrane. Specimens were prepared by cutting beetle wing carefully with a size of 3.0 mm in width and 5.0 mm in
length. We used a scanning electron microscope for exactly measuring the membrane thickness of a beetle wing
membrane. The specimen was attached to a designed fixture to induce a uniform displacement using a micromanipulator.
We measured the applied load and the corresponding displacement by a load cell with a maximum capacity of 5 N and
by an ARAMIS system based on the digital image correlation method respectively. The measured thickness of a beetle
wing varied from point to point of the wing part and the elastic modulus was different according to the loading direction.
In conclusion, we successfully measured the elastic modulus of a beetle wing with an ARAMIS system based on the
digital image correlation method.
Nowadays active vibration suppression of flexible manipulators is important in many engineering applications, such as
robot manipulators and high-speed flexible mechanisms. The demand for short settling time and low energy
consumption of the vibration suppression has necessitated the consideration to optimal control. For a wide range of
operating conditions, the fixed optimal parameters determined for a control algorithm might not produce the highest
performance. Hence, a self-tuning optimal control method for a flexible manipulator should be used to enhance the
performance. This method can tune itself to the optimal parameters on the basis of the initial maximum responses of the
controlled system. In this study, the multi-objective genetic algorithm is used to search for optimal parameters with
regard to positive position feedback, thereby minimizing the settling time and energy consumption multi-objective
functions. The experimental results reveal that the energy consumption can be reduced significantly while the settling
time is still slightly increased.
We have analyzed and experimentally examined the flapping performances in terms of aerodynamic force generation,
flapping frequency and flapping angle of the two flappers actuated by the original LIPCA and the compressed LIPCA,
respectively. The flapping tests for two wing shapes were conducted at three different wing rotation angles and various
flapping frequencies to search for the optimum flapping frequency, at which the maximum aerodynamic force was
achieved, and investigate the effect of wing shape and wing rotation angle on the force generation of the flapper. The
aerodynamic forces were calculated by subtracting the inertia forces measured in the vacuum from the total forces
measured in the air. For the CFD simulation, we established the corresponding kinematical equations of the wing by
examining the high-speed camera images taken from front and top at the same time. The experimental results showed we
could improve the flapping angle 18.2 % and the average vertical aerodynamic force 24.5 % by using the compressed
LIPCA.
This paper presents an experiment and parametric study of a biomimetic fish robot actuated by the Lightweight Piezocomposite
Actuator (LIPCA). The biomimetic aspects in this work are the oscillating tail beat motion and shape of
caudal fin. Caudal fins that resemble fins of BCF (Body and Caudal Fin) mode fish were made in order to perform
parametric study concerning the effect of caudal fin characteristics on thrust production at an operating frequency range.
The observed caudal fin characteristics are the shape, stiffness, area, and aspect ratio. It is found that a high aspect ratio
caudal fin contributes to high swimming speed. The robotic fish propelled by artificial caudal fins shaped after
thunniform-fish and mackerel caudal fins, which have relatively high aspect ratio, produced swimming speed as high as
2.364 cm/s and 2.519 cm/s, respectively, for a 300 Vp-p input voltage excited at 0.9 Hz. Thrust performance of the
biomimetic fish robot is examined by calculating Strouhal number, Froude number, Reynolds number, and power
consumption.
In this study, the actuation displacement and blocking force of the LIPCA (Lightweight Piezo-Composite Actuator)
under various combination of the external compressive load and prescribed voltage have been numerically and
experimentally examined. For numerical analysis, the full three-dimensional model of the LIPCA including two end-tabs
in the simply supported configuration was used and the measured nonlinear behavior of the bare piezoceramic wafer
(3203HD, CTS) was implemented in the geometrically nonlinear finite element analysis. The central out-of-plane
displacement of the LIPCA was measured while applying various electric fields and compressive loads at the same time.
Dummy weights were added at the center of the LIPCA until the LIPCA cannot produce additional central actuation
displacement for a given excitation voltage and the sum of the dummy weight was regarded as the blocking force. The
numerical results acquired by geometrical/material nonlinear finite element analysis and the measured data showed a
good agreement even for high electric field and compressive load. The investigation showed that the actuation
displacement and blocking force of the LIPCA were significantly increased by pre-applied compressive load. At the
same electric field, the actuation displacements of the LIPCA under nearly buckling load could be about two times larger
than those without compressive load. The results also indicate that the positive voltage should be better applied to the
actuator than the negative voltage. Therefore, the high negative electric field, which causes the polarization switching in
the piezoceramic wafer, can be avoided in applications. At +150V, the blocking force of the compressed actuator under
near buckling load was also increased around 26% higher than that of the actuator without compressive load.
In this work, behavior of a unimorph piezoceramic actuator, LIPCA (Lightweight Piezo-Composite Actuator) under compression has been experimentally and numerically investigated. The LIPCA composed of composite laminated tabs, piezoceramic material layer, glass/epoxy composite and carbon fiber composite layers was modeled and analyzed by using a full three-dimensional finite element modeling technique. The geometrically nonlinear analysis was used in the analysis because the LIPCA has the initial curvature due to the curing process, which acts like an initial geometric imperfection. The LIPCA was installed in the simply supported configuration and compressive load was applied in the test jig. By measuring the lateral displacement created by the compressive load, the buckling load of the LIPCA was determined. The measured buckling load agreed well with the computed linear buckling load from the finite element analysis based on the thermal analogy. As various electric fields were applied to the LIPCA under the compressive load, the lateral displacement was measured to examine behavior of the LIPCA under the compressive load and electric field at the same time. From this test, proper combinations of the compressive load and prescribed voltage could be figured out, which can create controlled buckling of the LIPCA under compression by applying the electric field. The measured data showed that the lateral displacement of the LIPCA is significantly increased when a proper electric field is prescribed to the LIPCA in addition to the pre-determined compressive load. The measured data was compared with the computed result from the geometrically nonlinear finite element analysis based on the thermal analogy. The numerical simulation agreed well with the measurement for low compressive load (< 3N) and low electric field (< 150V). The strength of the LIPCA is also calculated to make sure that the actuator can be operated without fracture.
This paper presents a mechanical design, fabrication and test of biomimetic fish robot using the Lightweight Piezocomposite Curved Actuator (LIPCA). We have designed a mechanism for converting actuation of the LIPCA into caudal fin movement. This linkage mechanism consists of rack-pinion system and four-bar linkage. We also have tested four types of caudal fin in order to examine effect of different shape of caudal fin on thrust generation by tail beat.
Subsequently, based on the caudal fin test, four caudal fins which resemble fish caudal fin shapes of ostraciiform, subcarangiform, carangiform and thunniform, respectively, are attached to the posterior part of the robotic fish. The swimming test using 300 Vpp input with 1 Hz to 1.5 Hz frequency was conducted to investigate effect of changing tail beat frequency and shape of caudal fin on the swimming speed of the robotic fish. The maximum swimming speed was reached when the device was operated at its natural swimming frequency. At the natural swimming frequency 1 Hz,
maximum swimming speeds of 1.632 cm/s, 1.776 cm/s, 1.612 cm/s and 1.51 cm/s were reached for ostraciiform-, subcarangiform-, carangiform- and thunniform-like caudal fins, respectively. Strouhal numbers, which are a measure of thrust efficiency, were calculated in order to examine thrust performance of the present biomimetic fish robot. We also approximated the net forward force of the robotic fish using momentum conservation principle.
This paper presents an improved version of the insect-mimicking flapping-wing mechanism actuated by LIPCA (Lightweight Piezo-Composite Actuator). As the previous version, the actuation displacement of the actuator is converted into flapping-wing motion by a mechanical linkage system that functioned as displacement amplifier as well. In order to provide feathering motion, the wing is attached to the axis through a hinge system that allows the wing rotation at each end of half-stroke, due to air resistance. In this improved version, the total weight has been reduced to the half of the previous one. The device could produce about 90 degree of flapping angle when it operated at around 10 Hz, which was the natural flapping-frequency. Several flapping tests under different parameter configurations were conducted in order to investigate the characteristic of the generated lift. In addition, the smoke-wire test was also conducted, so that the vortices around the wing can be visually observed. Even though the present wing has smaller wing area, it could produce higher lift then before.
Manufacturing and characterization of ionic polymer metal composites (IPMCs) with silver as electrodes have been investigated. Tollen's reagent that contains ion Ag(NH3)2+ was used as a raw material for silver deposition on the surfaces of the polymer membrane Nafion"R". Two types of inner solvents, namely common water based electrolyte solution (LiOH 1N) and ionic liquid were used and investigated. Compared to IPMCs with platinum electrodes, silver-plated IPMCs with water electrolyte showed higher conductivity. The actuation response of silver-plated IPMCs with the water based electrolyte was faster than that of platinum IPMCs. However, the silver electrode was too brittle and severely damaged during the solvent exchange process from water to ionic liquid, resulted in high resistance and hence very low actuation behavior.
The degradation mechanism of ionic polymer metal composites (IPMCs) containing hydrophobic ionic liquids has been investigated. The ionic liquid was mixed with ethylene glycol in order to obtain high solvent uptake. The actuation response of the IPMCs with the mixed solvent was faster than that with only ethylene glycol. During the actuation durability tests under an AC square wave input, the IPMCs suffered from liquid squeezing-out problem, resulting in lower solvent concentration inside the IPMCs and hence poor actuation response. The degradation development of the IPMCs was influenced by the applied AC frequency. The tip displacement and the electric current were used to study the degradation development under AC electric field. Tin layer of polyurethane was applied on the IPMC surface to minimize the squeezing problems. The degradation was not significant observed after being subjected to 3V square wave input for more than 20 hours. However, the conductivity of the coated IPMCs was lower than that of the uncoated ones.
In this paper, we present design, manufacturing, and wind tunnel test for a small-scale expandable morphing wing. The wing is separated into inner and outer wings as a typical bird wing. The part from leading edge of the wing chord is made of carbon composite strip and balsa. The remaining part is covered with curved thin carbon fiber composite mimicking wing feathers. The expandable wing is driven by a small DC motor, reduction gear, and fiber reinforced composite linkages. Rotation of the motor is switched to push-pull linear motion by a screw and the linear motion of the screw is transferred to linkages to create wing expansion and folding motions. The wing can change its aspect ratio from 4.7 to 8.5 in about 2 seconds and the speed can be controlled. Two LIPCAs (Lightweight Piezo-Composite Actuators) are attached under the inner wing section and activated on the expanded wing state to modify camber of the wing. In the wind tunnel test, change of lift, drag, and pitching moment during wing expansion have been investigated for various angles of attack. The LIPCA activation has created significant additional lift.
In this paper, we present our recent progress in LIPCA (Lightweight Piezo-Composite Actuator) application for actuation of flapping wing device. The flapping device uses linkage system that can amplify the actuation displacement of LIPCA. The feathering mechanism is also designed and implemented such that the wing can rotate during flapping. The natural flapping-frequency of the device was 9 Hz, where the maximum flapping angle was reached. The flapping test under 4 Hz to 15 Hz flapping frequency was performed to investigate the flapping performance by measuring the produced lift and thrust. Maximum lift and thrust produced when the flapping device was actuated near the natural flapping-frequency.
KEYWORDS: Ferroelectric materials, Actuators, Active vibration control, Control systems, Aluminum, Power supplies, Structural dynamics, Switching, Circuit switching, Data acquisition
This paper presents the application of Lightweight Piezo-composite Curved Actuator (LIPCA) to suppress vibration as actuator. LIPCA is composed of a piezoelectric layer, a carbon/epoxy layer and glass/epoxy layers. When compared to the bare piezoelectric ceramic (PZT), LIPCA has advantages such as high performance, durability and reliability. In this study, performances of LIPCA are estimated in an active vibration control system. Experiments are performed on an aluminum beam by cantilever configuration. In this test, strain gages and single LIPCA are attached on the aluminum beam with epoxy resin in order to investigate their performance. Comparison of actuation force between LIPCA and bare PZT showed that performance of LIPCA was better than that of bare PZT. In addition, digital on-off control algorithm is applied into the system to exhibit performance of LIPCA as actuator in active vibration control system. The results showed LIPCA could suppress free vibration of the aluminum beam. It is possible to apply LIPCA as actuator to control vibration of dynamic structures.
This paper presents the design and analysis of an IPMC (Ionic Polymer-Metal Composite) driven micropump. It should be noted that IPMC is a promising material candidate for micropump applications since it can be operated with low input voltages and can produce large stroke volumes along with controllable flow rates. Moreover, the micropump manufacturing process with IPMC is convenient. It is anticipated that the manufacturing cost of the IPMC micropump is competitive when compared to other competing technologies. In order to design an effective IPMC diaphragm that functions as an actuating motor for a micropump, a finite element analysis was utilized to optimize the shape of IPMC diaphragm and estimate stroke volume through several parametric studies. In addition, effect of the pump chamber's pressure on the stroke volume was numerically investigated. Appropriate inlet and outlet nozzle/diffusers for the micropump were also chosen. Based on the selected geometry of nozzle/diffusers and the estimated stroke volume, flow rate of the IPMC micropump was predicted.
An IMPC actuated flapping wing has been designed and demonstrated for mimicking flapping motion of a bird wing. The flapping wing can produce twist motion as well as flap up and down motions. For design of the wing, an equivalent beam model has been proposed based on the measured force-displacement data. The equivalent model is used to determine suitable IPMC actuator patterns that can create twist motion during up- and down-strokes of the wing. The IPMC actuator pattern is inserted in a wing-shaped plastic film to form a complete flapping wing. Experimental results show that the properly shaped IPMCs can create aniosotropic motion that is often required for producing effective thrust and lift forces in bird flight.
In this paper, we present our recent progress in application of LIPCA (LIghtweight Piezo-Composite Actuator) to design and demonstration of a flapping wing device. The flapping device has flexible wings actuated by the LIPCA. The device is designed such that it can create twist motion during up- and down-stroke like bird or insect wings. The motion could be generated by using LIPCA actuator pivoted to the wing. The wing can bend and twist due to bending-twist coupling of the specially designed pivot system. Experimental results show that the properly designed flapping device powered by LIPCA can create anisotropic motion that is often required for producing effective thrust and lift forces in bird or insect flight.
In this paper, material nonlinear behavior of PZT wafer (3202HD, CTS) under high electric field and tensile stress is experimentally investigated and the nonlinearity of the PZT wafer is numerically simulated. In the simulation, new definitions of the piezoelectric constant and the incremental strain are proposed. Empirical functions that can represent the nonlinear behavior of the PZT wafer have been extracted based on the measured piezo-strain under stress. The functions are implemented in an incremental finite element formulation for material nonlinear analysis. With the new definition of the incremental piezo-strain, the measured nonlinear behavior of the PZT wafer has been accurately reproduced even for high electric field.
This paper describes the development of biomimetic structure systems with LIPCA (LIghtweight Piezo-Composite Actuator) and battery supported power control unit. To apply LIPCA as a biomimetic actuator for the control surface of small unmanned air vehicle, a battery supported power control unit was developed, which is composed of a lithium polymer, one step-up converter, four power switching high voltage transistors, on Schmitt triggered comparator, and control logics. A simple RC circuit is used to sample the voltage applied to the LIPCA. H-switch was applied which is composed of the four high voltage transistors to control the voltage or charge and its polarity applied to the LIPCA. From experiments, it was observed that the developed biomimetic adaptronic systems could be constructed with relatively compact and light units and could produce enough displacement and force to be used as a control surface for the elevator and the rudder of a small unmanned vehicle.
This paper is concerned with the fatigue characteristics of LIPCA (LIghtweight Piezo-Composite Actuator) device systems, composed of a piezoelectric ceramic layer and fiber reinforced light composite layers, where the PZT ceramic layer is typically sandwiched by a top fiber layer with a low CTE (coefficient of thermal expansion) and base layers with a high CTE. The advantages of the LIPCA design include the use of lightweight fiber reinforced plastic layers without compromising the generation of a high force and large displacement, and design flexibility in selecting the fiber direction and size of the prepreg layers. In addition, a LIPCA device can be manufactured without adhesive layers since epoxy resin plays role of bonding material. To investigate the degradation of the actuation performance of LIPCAs due to repeated fatigue loading, repeated loading tests up to several million cycles were performed and the actuation displacement for a given excitation voltage measured during the test. The fatigue characteristics were measured using an actuator test system consisting of an actuator-supporting jig, high-voltage actuating power supplier, and non-contact laser measuring system and evaluated.
Biomimetic wing sections actuated by piezoceramics actuator LIPCA have been designed and their actuation displacements estimated by using the thermal analogy and MSC/NASTRAN based on the linear elasticity. The wing sections are fabricated as the design and tested for evaluation. Measured actuation displacements were larger than the estimated values mainly due to the material non-linearity of the PZT wafer. The biomimetic wing sections can be used for control surfaces of small scale UAVs.
In the present work, the existing formulation of nine-node shell element based on Hellinger-Reissner principle is expanded for electro-mechanically coupled field analysis. The electro-mechanical coupling effect of the piezoelectric material is introduced to the formulation through the constitutive relation. Based on the formulation, a linear finite element code is constructed and it is validated by several numerical tests. By using the code, linear analysis of LIPCA(LIghtweight Piezoelectric Composite Actuator) is performed to calculate actuation displacement and stress. Moreover, to improve simulation result more accurately, an experimental piezo-strain function of PZT(3203HD, CTS) wafer that is embedded in LIPCA is obtained from measured data and the function is implemented into the code by adopting incremental method. And then, the actuation displacement of LIPCA is recalculated and the result is compared with the measured data.
KEYWORDS: Actuators, Ceramics, Ferroelectric materials, Manufacturing, Laser systems engineering, Semiconducting wafers, Design for manufacturability, Epoxies, Composites, Active vibration control
This paper is concerned with the performance evaluation and comparison for several kinds of LIPCA device system. LIPCA device system is composed of a piezoelectric ceramic layer and fiber reinforced light composite layers, typically a PZT ceramic layer is sandwiched by a top fiber layer with low CTE and base layers with high CTE. To investigate the effect of lay-up structure of the LIPCA system, four kinds of actuator with different lay-up stacking sequence have been designed, manufactured, and tested. The performance of each actuator was evaluated using an actuator test system consisted of an actuator supporting jig, a high voltage actuating power supplier, and a non-contact laser measuring system. From the comparison of the performance of the LIPCA prototypes, it was found that the actuator with larger actuation moment arm length and lower total flexural stiffness can generate larger actuating displacement.
This paper deals with a fully coupled assumed strain solid element that can be used for simultaneous moiling of thin sensors and actuators. To solve fully coupled field problems, electric potential is regarded as a nodal degree of freedom in addition to three translations in an eighteen node assumed strain solid element. Therefore, the induced electric potential can be calculated for a prescribed deformation or an applied load. Since the original assumed strain solid element is free of locking, the element can be used to analyze behavior of very thin actuators without locking. Numerical examples, such as a typical bimorph actuator/sensor beam problem shows that the present element can handle fully coupled problems. Using the solid element, we have analyzed the actuation performance of THUNDER and compared the result with measured data. The comparison shows that the numerical estimation agrees well with measured displacement for simply supported boundary condition. It is also found that a particular combination of materials for layers and curvature of THUNDER improve actuation displacement.
LIPCA (LIghtweight Piezo-composite Curved Actuator) is an actuator device which is lighter than other conventional piezoelectric ceramic type actuator. LIPCA is composed of a piezoelectric ceramic layer and fiber reinforced light composite layers, typically a PZT ceramic layer is sandwiched by a top fiber layer with low CTE (Coefficient of thermal expansion) and base layers with high CTE. LIPCA has curved shape like a typical THUNDER (Thin-layer composite unimorph ferroelectric driver and sensor), but it is lighter than THUNDER. Since the curved shape of LIPCA is from the thermal deformation during the manufacturing process of unsymmetrically laminated lay-up structure, and analysis for the thermal deformation and residual stresses induced during the manufacturing process is very important for an optimal design to increase the performance of LIPCA. To investigate the thermal deformation behavior and the induced residual stresses of LIPCA at room temperature, the curvatures of LIPCA were measured and compared with those predicted from the analysis using the classical lamination theory. A methodology is being studied to find an optimal stacking sequence and geometry of LIPCA to have larger specific actuating displacement and higher force. The residual stresses induced during the cooling process of the piezo- composite actuators have been calculated. A lay-up geometry for the PZT ceramic layer to have compression stress in the geometrical principal direction has been designed.
A numerical method for the performance evaluation of LIPCA actuators is proposed using a finite element method. Fully-coupled formulations for piezo-electric materials are introduced and eight-node incompatible elements used. After verifying the developed code, the behavior of LIPCA actuators is investigated.
This paper is concerned with design, manufacturing and performance test of lightweight THUNDER using a top fiber composite layer with near-zero CTE, a PZT ceramic wafer and a bottom glass/epoxy layer with high CTE. The main point of this design is to replace the heavy metal layers of THUNDER by the lightweight fiber reinforced plastic layers without losing capabilities to generate high force and displacement. It is possible to save weight up to about 30 percent if we replace the metallic backing materials by the light fiber composite layer. We can also have design flexibility by selecting the fiber direction and the size of prepreg layers. In addition to the lightweight advantage and design flexibility, the proposed device can be manufactured without adhesive layers when we use epoxy resin prepreg system. Glass/epoxy prepregs, a ceramic wafer with electrode surfaces, and a graphite/epoxy prepreg were simply stacked and cured at an elevated temperature by following autoclave bagging process. It was found that the manufactured composite laminate device had a sufficient curvature after detaching form a flat mold. From experimental actuation tests, it was observed that the developed actuator could generate larger actuation displacement than THUNDER.
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