Piezoceramic functional grading methods, such as the Dual Electro/Piezo Property (DEPP) technique, can successfully produce monolithic actuators which generate higher order deformations when activated (bending, twisting, etc.) while simultaneously increasing reliability by eliminating bonding layers. By synergistically combining ceramic powder with elevated piezoelectric coefficients with a high permittivity dielectric, DEPP actuators are not constrained to the one dimensional property variations as other grading methods. This paper explores the new capability of producing multi-dimensionally graded piezoceramics via the DEPP technique coupled with the Micro-Fabrication by Co-eXtrusion (MFCX) process. It also presents a modeling technique based upon transfer matrix method that builds up the full actuator performance model from elemental beam models derived using an energy approach which captures all the material variations and the resulting complex electric fields. To validate both the fabrication and modeling techniques, a rippling DEPP FGP actuator was fabricated and tested with three oppositely graded regions, demonstrating two dimensional gradients through the length and thickness. This work sets the foundation for monolithic multi-dimensional FGP opening the door to a new class of applications.

This paper presents a study in which clamped unimorph rectangular piezoelectric diaphragms are analyzed to determine the importance of electrode patterning. There has been a great deal of interest in getting increased deflection out of smaller piezoelectric devices with lower input power. In previous work, it has been shown that a clamped circular diaphragm can generate much increased deflection in response to an electric loading when the electrode has a "regrouped" pattern. Regrouping refers to the process of segmenting the electrodes into regions that are electrically disconnected so that the corresponding polarity can be set in opposite directions. The rectangular diaphragm actuator is studied in this paper to determine the effects of electrode patterns and the shape of the piezoelectric layer on the actuator's static displacement. From the analytical results, it is shown that regrouping the electrode pattern on a rectangular actuator can increase deflection, and subsequently volumetric displacement, by many times.

Positioning precision is crucial to today's increasingly high-speed, high-capacity, high data density, and miniaturized hard disk drives (HDDs). The demand for higher bandwidth servo systems that can quickly and precisely position the read/write head on a high track density becomes more pressing. Recently, the idea of applying dual-stage actuators to track servo systems has been studied. The push-pull piezoelectric actuated devices have been developed as micro actuators for fine and fast positioning, while the voice coil motor functions as a large but coarse seeking. However, the current dual-stage actuator design uses piezoelectric patches only without passive damping. In this paper, we propose a dual-stage servo system using enhanced active-passive hybrid piezoelectric actuators. The proposed actuators will improve the existing dual-stage actuators for higher precision and shock resistance, due to the incorporation of passive damping in the design. We aim to develop this hybrid servo system not only to increase speed of track seeking but also to improve precision of track following servos in HDDs. New piezoelectrically actuated suspensions with passive damping have been designed and fabricated. In order to evaluate positioning and track following performances for the dual-stage track servo systems, experimental efforts are carried out to implement the synthesized active-passive suspension structure with enhanced piezoelectric actuators using a composite nonlinear feedback controller.

Due to improvements in material properties through research, actuation mechanisms utilizing shape memory alloys (SMA) have been attracting more attention. Many actuation mechanisms have utilized the phase transformation of SMA's to generate motion. One new arena for the application of the alloys is the automotive industry, where they can reduce size and cost of the actuator in current models. The three major types of actuators employing SMA wires will be discussed. One such type, the antagonistic actuator, has begun to find applications where position can be controlled through the use of SMA wire. Based on this antagonistic actuator, a novel two degree of freedom SMA actuator is proposed which controls the position of an external rear view mirror. This design would replace the current DC motor design with a cheaper and more compact mechanism. The prototype concept is implemented using an antagonistic actuator based on an SMA wire, a joystick and a microcontroller.

The response of NiMnGa ferromagnetic shape memory alloy to static and dynamic magnetic fields was studied. Tests involving excitation of the samples up to 10 Hz for constant stress and constant strain conditions were conducted. Based on these results, performance parameters were measured and discussed including power density, total power output and electromechanical efficiency. The effects of strain rate and material damping were also measured. It was shown that both power density and total power output were strong functions of applied stress. A maximum volumetric power density of 31 MW/m³ was measured. Once the NiMnGa behavior was characterized, an analytical model based on four experimentally measured parameters was formulated to predict the induced strain in response to a dynamic magnetic field. Comparison of the analytical model to experimental data showed good correlation for applied stresses below 0.6 MPa and above 1.33 MPa. Although requiring further refinement, the model's results are encouraging, indicating that it could be developed into a useful analytical tool for predicting NiMnGa actuator behavior.

FSMAs like Ni₂MnGa have attracted significant attention over the last few years. As actuators, these materials offer high energy density, large stroke, and high bandwidth. These properties make FSMAs potential candidates for developing Solid-Fluid Hybrid Actuations (SFHA), where the FSMA actuator provides the mechanical energy by the linear reversible displacements. In order to develop effective hydraulic pumps with the FSMA actuators, it is important to study the dynamic behavior in these materials. In this paper, a dynamic model is presented for an Ni₂MnGa actuator. The Ni₂MnGa actuator model consists of the dynamics of the actuator, kinematics of the actuator, constitutive model of the material, and reorientation kinetics. A constitutive model is proposed to take into account the elastic deformation as well as the reorientation. Simulations results are presented to demonstrate the dynamic behavior of the actuator.

Short-bowel syndrome (SBS) is a rare, potentially lethal medical condition where the small intestine is far shorter than required for proper nutrient absorption. Current treatment, including nutritional, hormone-based, and surgical modification, have limited success resulting in 30% to 50% mortality rates. Recent advances in mechanotransduction, stressing the bowel to induce growth, show great promise; but for successful clinical use, more sophisticated devices that can be implanted are required. This paper presents two novel devices that are capable of the long-term gentle stressing. A prototype of each device was designed to fit inside a short section of bowel and slowly extend, allowing the bowel section to grow approximately double its initial length. The first device achieves this through a dual concentric hydraulic piston that generated almost 2-fold growth of a pig small intestine. For a fully implantable extender, a second device was developed based upon a shape memory alloy actuated linear ratchet. The proof-of-concept prototype demonstrated significant force generation and almost double extension when tested on the benchtop and inside an ex-vivo section of pig bowel. This work provides the first steps in the development of an implantable extender for treatment of SBS.

A novel Morphing Flight Control Surface (MFCS) system has been developed. The distinction of this research effort is that the SenAnTech team has incorporated our innovative Highly Deformable Mechanism (HDM) into our MFCS. The feasibility of this novel technology for deformable wing structures, such as airfoil shaping, warping or twisting with a flexure-based high displacement PZT actuator has been demonstrated via computational simulations such as Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD). CFD was implemented to verify the accuracy of the complex potential flow theory for this application. Then, complex potential flow theory, kinematics, geometry, and static force analysis were incorporated into a multidisciplinary GUI simulation tool. This tool has been used to aid the design of the MFCS. The results show that we can achieve up to five degrees of wing twisting with our proposed system, while using minimal volume within the wing and adding little weight.

The Micro Aerial Vehicle (MAV) represents a strategic and industrial goal. The challenge is truly technical, as the needs are very specific in terms of mission and efficiency. The aerospace French agency (Onera ) has launched an internal program on that purpose including many research topics, essential to understand how to reach the goals. Thus, aerodynamic (generally unsteady with low Reynolds number), structural dynamics, propulsion, actuation, control,.. are being studied in this field. On a structural and mechanical actuation point of view, presently our main interest, the problem is already very large. So before analyzing and formulating, we found not so meaningless to look how nature proceeds and to start a design study with a "biologically-inspired" approach (dragonfly).

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.

There have been persistent interests in high performance actuators suitable for the actuation of control surfaces of small aircraft and helicopter blades and for active vibration control of aerospace and submarine structures that need high specific force and displacement. What is really needed for active actuation is a large-displacement actuator with a compact source, i.e., much higher strain. A lot of effort has been made to develop compact actuators with large displacement at a high force. One of the representative actuator is LIPCA actuator that was introduced by Yoon et al. The LIPCA design offers the advantages to be applied as actuator for the small aerial vehicle comparing with any other actuators. The weight is one of the main concerns for aerospace field, and since LIPCA has lighter weight than any other piezo-actuator thus it is suitable as actuator for small aircraft control surface. In this paper, a conceptual design of LIPCA-actuated control surface is introduced. A finite element model was constructed and analyzed to predict the deflection angle of the control surface. The hinge moment that produced by the aerodynamic forces was calculated to determine the optimum position of the hinge point, which could produce the deflection as high as possible with reasonable hinge moment. To verify the prediction, a prototype of SUAV (small unmanned air vehicle) control surface was manufactured and tested both in static condition and in the wind tunnel. The prediction and test results showed a good agreement on the control surface deflection angle.

This paper presents the use of a new class of flight control actuators employing Post-Buckled Precompressed (PBP) piezoelectric elements in morphing wing Uninhabited Aerial Vehicles (UAVs). The new actuator relies on axial compression to amplify deflections and control forces simultaneously. Two designs employing morphing wing panels based on PBP actuators were conceived. One design employed PBP actuators in a membrane wing panel over the aft 60% of the chord to impose roll control on a 720mm span subscale UAV. This design relied on a change in curvature of the actuators to control the camber of the airfoil. Axial compression of the actuators was ensured by means of rubber bands and increased end rotation levels with almost a factor of two up to ±13.6° peak-to-peak, with excellent correlation between theory and experiment. Wind tunnel tests quantitatively proved that wing morphing induced roll acceleration levels in excess of 1500 deg/s². A second design employed PBP actuators in a wing panel with significant thickness, relying on a highly compliant Latex skin to allow for shape deformation and at the same time induce an axial force on the actuators. Bench tests showed that due to the axial compression provided by the skin end rotations were increased with more than a factor of two up to ±15.8° peak-to-peak up to a break frequency of 34Hz. Compared to conventional electromechanical servoactuaters, the PBP actuators showed a net reduction in flight control system weight, slop and power consumption for minimal part count. Both morphing wing concepts showed that PBP piezoelectric actuators have significant benefits over conventional actuators and can be successfully applied to induce aircraft control.

In the present study, we have developed a smart flapping wing with a MFC (macro-fiber composites) actuator. To mimic the flying mechanisms of nature's flyers such as birds or insects, the aerodynamic characteristics related to the birds and ornithopters are investigated. To measure the aerodynamic forces of flapping devices, a test stand consisting of two loadcells is manufactured, and the dynamic tests are performed for an onithopter. The smart flapping wing is designed and manufactured using composite materials and MFC actuators. The camber of the wing can be changed by using the surface actuators to enhance the aerodynamic performance of the wing. Finally, aerodynamic tests are performed in a subsonic wind tunnel to evaluate the dynamic characteristics of the smart flapping wing. Experimental results show that unsteady flow effects are increased with low velocity in high flapping frequency regions, and that the deformation of the wing surface generated by the MFC is enough to control the lift and thrust. The lift generated by the smart flapping wing can be increased by 20% when the MFC is actuated.

An energy-harvesting thermoelectric generator (TEG) is being developed to provide power for wireless sensors used in health monitoring of Navy machinery. TEGs are solid-state devices that convert heat directly into electricity without any moving parts. In this application, the TEGs utilize the heat transfer between shipboard waste heat sources and the ambient air to generate electricity. In order to satisfy the required small design volume of less than one cubic inch, Hi-Z is using its innovative thin-film Quantum Well (QW) thermoelectric technology that will provide a factor of four increase in efficiency and a large reduction in the device volume over the currently used bulk Bi₂Te₃ based thermoelectics. QWs are nanostructured multi-layer films. These wireless sensors can be used to detect cracks, corrosion, impact damage, and temperature and vibration excursions as part of the Condition Based Maintenance (CBM) of the Navy ship machinery. The CBM of the ship machinery can be significantly improved by automating the process with the use of self-powered wireless sensors. These power-harvesting TEGs can be used to replace batteries as electrical power sources and to eliminate power cables and data lines. The first QW TEG module was fabricated and initial tests were successful. It is planned to conduct performance tests the entire prototype QW TEG device (consisting of the TEG module, housing, thermal insulation and the heat sink) in a simulated thermal environment of a Navy ship.

This paper presents force-feedback control performance of a new type of haptic device featuring spherical geometry and smart materials that can be used for minimally invasive surgery (MIS). A spherical electrorheological (ER) joint is designed and optimized based on the mathematical torque modeling. Force response of the manufactured ER joint is then experimentally evaluated. Subsequently, the 2-DOF force-feedback device is manufactured by integrating the spherical ER joint with AC motor. In order to achieve desired force trajectories of the haptic device, a sliding mode controller (SMC), which is robust to uncertainty, is formulated and experimentally realized. Tracking control performances for various force trajectories are presented in time domain, and their tracking errors are evaluated.

A major limitation of current dedicated impact energy management structures and passive devices used in the transportation industry is that their starting volume is their maximum volume, i.e. they dissipate energy by crushing or stroking from a larger to a smaller volume. This space so occupied is not available for other uses, including such necessary/desirable functions as vehicle serviceability and repair, operational clearances, and interior spaciousness. This limitation has led to the proposal of a class of "smart" impact energy management devices, based on unexpanded aluminum honeycomb (HOBE), that initially occupy a small volume and based on sensor input are rapidly expanded to a much larger crushable volume (nominally 75 times greater) just prior to or in response to an impact. This paper documents the first portion of an experimental exploration of the viability of this technology. Specific goals of the herein documented test program were the demonstration, starting from blocks of unexpanded aluminum honeycomb, a) of the feasibility (and robustness) of sensor triggered rapid expansion both in terms of the integrity and uniformity of the resulting expanded honeycomb, and b) that expansion mechanisms that were required could be simple and have low energy/force requirements. The test program documented here was successful in both respects, demonstrating and thus validating the feasibility and robustness of low energy rapid expansion of aluminum honeycomb.

Synthetic Jet Actuators have been the topic of extensive study in the aerospace industry because of their ability to actively control flow over aerodynamic surfaces without discrete control surfaces such as a flap. One challenge has been to develop a low frequency, lightweight actuator that can provide large displacements. This study will discuss the modeling, design, manufacture, and testing of a bimorph piezo-composite actuator that will provide such displacements at low frequencies. The design employs two opposing benders that provide a piston-type motion. The initial goals of this study were to achieve 30 m/s out of the slot while maintaining the mechanical resonant frequency of the system at about 100 Hz.

Present study is looking at the problem of integrating drug delivery microcapsule, a bio-sensor, and a control mechanism into a biomedical drug delivery system. A wide range of medical practices from cancer therapy to gastroenterological treatments can benefit from such novel bio-system. Drug release in our drug delivery system is achieved by electrochemically actuating an array of polymeric valves on a set of drug reservoirs. The valves are bi-layer structures, made in the shape of a flap hinged on one side to a valve seat, and consisting of thin films of evaporated gold and electrochemically deposited polypyrrole (PPy). These thin PPy(DBS) bi-layer flaps cover access holes of underlying chambers micromachined in a silicon substrate. Chromium and polyimide layers are applied to implement "differential adhesion" to obtain a voltage induced deflection of the bilayer away from the drug reservoir. The Cr is an adhesion-promoting layer, which is used to strongly bind the gold layer down to the substrate, whereas the gold adheres weakly to polyimide. Drug actives (dry or wet) were pre-stored in the chambers and their release is achieved upon the application of a small bias (~ 1V). Negative voltage causes cation adsorption and volume change in PPy film. This translates into the bending of the PPy/Au bi-layer actuator and release of the drug from reservoirs. This design of the drug delivery module is miniaturized to the dimensions of 200μm valve diameter. Galvanostatic and potentiostatic PPy deposition methods were compared, and potentiostatic deposition method yields film of more uniform thickness. PPy deposition experiments with various pyrrole and NaDBS concentrations were also performed. Glucose biosensor based on glucose oxidase (GOx) embedded in the PPy matrix during elechtrochemical deposition was manufactured and successfully tested. Multiple-drug pulsatile release and continuous linear release patterns can be implemented by controlling the operation of an array of valves. Varying amounts of drugs, together with more complex controlling strategies would allow creation of more complex drug delivery patterns.

To solve a wide range of vibration problems with the active structures technology, different simulation approaches for several models are needed. The selection of an appropriate modeling strategy is depending, amongst others, on the frequency range, the modal density and the control target. An active system consists of several components: the mechanical structure, at least one sensor and actuator, signal conditioning electronics and the controller. For each individual part of the active system the simulation approaches can be different. To integrate the several modeling approaches into an active system simulation and to ensure a highly efficient and accurate calculation, all sub models must harmonize. For this purpose, structural models considered in this article are modal state-space formulations for the lower frequency range and transfer function based models for the higher frequency range. The modal state-space formulations are derived from finite element models and/or experimental modal analyses. Consequently, the structure models which are based on transfer functions are directly derived from measurements. The transfer functions are identified with the Steiglitz-McBride iteration method. To convert them from the z-domain to the s-domain a least squares solution is implemented. An analytical approach is used to derive models of active interfaces. These models are transferred into impedance formulations. To couple mechanical and electrical sub-systems with the active materials, the concept of impedance modeling was successfully tested. The impedance models are enhanced by adapting them to adequate measurements. The controller design strongly depends on the frequency range and the number of modes to be controlled. To control systems with a small number of modes, techniques such as active damping or independent modal space control may be used, whereas in the case of systems with a large number of modes or with modes that are not well separated, other control concepts (e.g. adaptive controllers) are more convenient. If other elements (e.g. signal amplifiers or filters) in the signal paths have a significant influence on the transfer functions, they must be modeled as well by an adequate transfer function model. All the different models described above are implemented into one typical active system simulation. Afterwards, experiments will be performed to verify the simulations.

Complex structural nonlinearities of piezoelectric materials drastically degrade their performance in variety of micro- and nano-positioning applications. From the precision positioning and control perspective, the multi-path time-history dependent hysteresis phenomenon is the most concerned nonlinearity in piezoelectric actuators to be analyzed. To realize the underlying physics of this phenomenon and to develop an efficient compensation strategy, the intelligent properties of hysteresis with the effects of non-local memories are discussed. Through performing a set of experiments on a piezoelectrically-driven nanostager with high resolution capacitive position sensor, it is shown that for the precise prediction of hysteresis path, certain memory units are required to store the previous hysteresis trajectory data. Based on the experimental observations, a constitutive memory-based mathematical modeling framework is developed and trained for the precise prediction of hysteresis path for arbitrarily assigned input profiles. Using the inverse hysteresis model, a feedforward control strategy is then developed and implemented on the nanostager to compensate for the system everpresent nonlinearity. Experimental results demonstrate that the controller remarkably eliminates the nonlinear effect if memory units are sufficiently chosen for the inverse model.

The dynamics of a self-sensing microcantilever beam for mass sensing applications are presented. The microcantilever is assumed to be uniform and obeying the Euler-Bernoulli beam theory assumptions. The beam possesses an unknown tip mass to be measured and a piezoelectric patch actuator deposited on the cantilever surface. The actuator is operated in a self-sensing mode, in the sense that the same piezoelectric patch is used to simultaneously actuate the beam and sense the voltage induced due to beam vibrations. A balanced impedance bridge is used to supply voltage to the piezoelectric actuator and to read the induced voltage. Mathematical models for this mechatronic system actuated through a pure capacitive and a resistive-capacitive bridge network are derived. Equations of motion are obtained using the Hamilton's principle by considering the microcantilever as a distributed-parameters system. A technique to estimate the unknown tip mass, based on the inverse solution to the characteristic equation problem is presented along with sensitivity analysis of the unknown mass with respect to the characteristic equation parameters. A closed-form solution for the determination of unknown tip mass is obtained which has many advantages over numerical estimation methods in a widespread mass sensing application.

This paper presents the concept, control strategy, and simulations of thrust vector control of satellites. First, an innovative thrust vector control concept is introduced, which utilizes the UHM multifunctional smart parallel manipulator to provide precision position control of the thruster vector and vibration suppression capability while the thruster fires. The configuration of the thrust vector control system is then illustrated, and the satellite attitude dynamic model is built. Third, the UHM smart parallel manipulator is introduced and its kinematics and controller design are discussed. The fuzzy logic controller is employed to precisely position the smart parallel manipulator and to compensate the non-linearities due to the friction and backlash of the actuators and the tolerance of the joints. Finally, the satellite attitude controller and the fuzzy logic controller are designed, and simulations are carried out to realize the thrust vector control of a satellite. The results indicate that the smart parallel manipulator can precisely achieve the thrust vector control, the misalignment of the trust vector of the satellite can be corrected effectively, and the position accuracy of the thrust vector is 0.68 arc minutes.

In this paper, admittance is introduced to represent electro-mechanical characteristics of piezoelectric structures and to predict the performance of piezoelectric shunt system. It is shown that admittance of the piezoelectric structure is proportional to the dissipated energy in the shunt circuit. Admittance is used as a design index to construct the piezoelectric shunt system and obtained by finite element method. Vibration reduction of the piezoelectric structure with shunt circuit is realized by experiments. Damped system response of piezoelectric structure in frequency and time domain proved that admittance is proportional to the performance of piezoelectric shunt system. Therefore, a new design method of piezoelectric shunt system using admittance analysis is proposed to save design cost of the piezoelectric structure.

The mission of the Fraunhofer Gesellschaft, one of the biggest research facilities in Germany, is to identify technologies with a high impact potential for commercial applications and to take all necessary steps to successfully promote them by performing cooperative industrial research activities. One of these technologies is called smart structures, also known as adaptive structures. Most recently, Fraunhofer decided to strategically extend its portfolio to include this technology and summarize its R&D activities in the FIT (Fraunhofer Innovation Topics) ADAPTRONIK. To improve Fraunhofer's competencies in adaptronics, especially with respect to system design and implementation, the Fraunhofer internal project MAVO FASPAS was launched in 2003. Now, after 3 years of work, the project comes to a close. This article discusses some major project results.

The methodology to restrain the growth of wrinkling region in inflatable boom is numerically and experimentally investigated. The inflatable boom structure is numerically modeled by using ABAQUS finite element program with membrane elements. To consider the nonlinear deformations of inflatable boom due to wrinkling, the numerical algorithm of wrinkling based on Miller-Hedgepeth membrane theory is developed using user defined material (UMAT) subroutine supported by ABAQUS. The experimental model of inflatable boom is made of Kapton film. To characterize the nonlinear behaviors of inflatable boom, the bending tests for various internal pressures are performed. To delay the growth of wrinkled region and restore the deformed shape of inflatable boom, shape memory alloy (SMA) wire actuator attached on surface of the structure is applied.

This paper discusses work relevant to small, low-cost, membrane-based lightweight adaptive fast steering mirrors. Small deformable membrane mirrors can in principle provide higher order modes such as defocus, coma, and astigmatism in addition to the frequently available tip and tilt modes. This work uses a small number of electrostatic actuators located very close to two opposite boundaries to avoid possible "print through" problems. A Green's function based formulation is used to obtain the analytical solution. The role of membrane tension on the available modes and stroke is examined in detail, and it is found that greater tension enables low-order correction modes, while small values of tension lead to higher order correction modes. Experimental work on an initial experimental model is also described.

Shape memory alloys (SMA) are a class of smart material having the unique ability to return to a predefined shape when heated. SMA based actuators have the potential to be very compact and low weight. As a result, much research has been devoted to the design of SMA based actuators; however, commercialization has been largely impeded by the small strain capacity inherent to SMA. To address this deficiency, this paper conveys the design of a large-strain SMA actuator (in excess of 30%) whose feasibility is investigated by integrating the actuators as artificial muscles in a two link anthropomorphic arm. The ensuing experimental results indicate that the actuators show great potential for a variety of emerging applications. Finally the design of an SMA based dextrous robotic hand evaluation facility is proposed, and provides a case study illustrating how smart structures provide a superior alternative to conventionally voluminous and heavy prosthetic actuators.

The smart material, Galfenol, is being explored for its uses as a magnetostrictive material. This project seeks to determine if Galfenol can be used as a tactile sensor in a 2-D grid array, magnetic circuit system. When used within a magnetic circuit, Galfenol indicates induced stress and force as a change in flux, due to a change in permeability of the material. The change in flux is detected by Giant MagnetoResistive (GMR) Sensors, which produce a voltage change proportional to the field change. By using Galfenol in an array, this research attempts to create a sensory area. Galfenol is an alloy made of Iron and Gallium. Fe_100-xGa_x, where 15 ≤ x ≤ 28, creates a material with useful mechanical and transduction attributes (Clark et al. and Kellogg). Galfenol is also distinguished by the crystalline structure of the material. Two types currently exist: single crystal and polycrystalline. Single crystal has higher transduction coefficients than polycrystalline, but is more costly. Polycrystalline Galfenol is currently available as either production or research grade. The designations are related to the sample growth rate with the slower rate being the research grade. The slower growth rate more closely resembles the single crystal Galfenol properties. Galfenol 17.5-18% research grade is used for this experiment, provided by Etrema Products Inc. The magnetic circuit and sensor array is first built at the macro scale so that the design can be verified. After the macro scale is proven, further development will move the system to the nano-level. Recent advances in nanofabrication have enabled Galfenol to be grown as nanowires. Using the nanowires, research will seek to create high resolution tactile sensors with spatial resolutions similar to human finger tips, but with greater force ranges and sensitivity capabilities (Flatau & Stadler). Possible uses of such systems include robotics and prosthetics.

This work is the first step to develop a programmable tactile array based on MR fluid technology. A prototype of display incorporating magnetorheological (MR) fluid has been developed and investigated. Electromagnets based on a commercial solenoid with several modifications are used as the magnetic field generator due to its small size. Surface force responses of the tactile display under various magnetic fields have been measured while a probe was moved across the upper surface. As the applied magnetic field was varied, the sensed surface profiles changed in synchronisation with the magnet field strength. With the MR actuator, the displayed surface information is stable and repeatable.

Twin-tail fighter aircraft such as the F/A-18 may experience intense buffet loads at high angles of attack flight conditions and the broadband buffet loads primarily excite the first bending and torsional modes of the vertical fin that results in severe vibration and dynamic stresses on the vertical fin structures. To reduce the premature fatigue failure of the structure and to increase mission availability, a novel hybrid actuation system was developed to actively alleviate the buffet response of a full-scale F/A-18 vertical fin. A hydraulic rudder actuator was used to control the bending mode of the fin by engaging the rudder inertial force. Multiple Macro Fiber Composites actuators were surface mounted to provide induced strain actuation authority to control the torsional mode. Experimental system identification approach was selected to obtain a state-space model of the system using open-loop test data. An LQG controller was developed to minimize the dynamic response of the vertical fin at critical locations. Extensive simulations were conducted to evaluate the control authority of the actuators and the performance of the controller under various buffet load cases and levels. Closed-loop tests were performed on a full-scale F/A-18 empennage and the results validated the effectiveness of the real-time controller as well as the development methodology. In addition, the ground vibration test demonstrated that the hybrid actuation system is a feasible solution to alleviate the vertical tail buffet loads in high performance fighter aircraft.

In this paper, a research for the performance improvement of the straight-bladed vertical axis wind turbine is described. To improve the performance of the power generation system, which consists of several blades rotating about axis in parallel direction, the cycloidal blade system and the individual active blade control system are adopted, respectively. Both methods are variable pitch system. For cycloidal wind turbine, aerodynamic analysis is carried out by changing pitch angle and phase angle based on the cycloidal motion according to the change of wind speed and wind direction, and control mechanism using the cycloidal blade system is realized for 1kw class wind turbine. By this method, electrical power is generated about 30% higher than wind turbine using fixed pitch angle method. And for more efficient wind turbine, individual pitch angle control of each blade is studied. By maximizing the tangential force in each rotating blade at the specific rotating position, optimal pitch angle variation is obtained. And several airfoil shapes of NACA 4-digit and NACA 6-series are studied. Aerodynamic analysis shows performance improvement of 60%. To realize this motion, sensing and actuating system is designed.

The Manta Ray, Manta birostris, is an amazing creature, propelling itself through the water with the elegant and complex flapping of its wings. Achieving outstanding efficiencies, engineers are looking for ways to mimic its flight through the water and harness its propulsive techniques. This study combines two biologically inspired aspects to achieve this goal: morphing structures actuated with a biomimetic neural network control system. It is believed that this combination will prove capable of producing the oscillatory motions necessary for locomotion. In this paper, a four-truss structure with three actuators is chosen and its performance capabilities are analyzed. A synthetic central pattern generator, which provides the fundamental control mechanisms for rhythmic motion in animals, is designed to realize an oscillatory control of the three actuators. The control system is simulated using Matlab, then combined with LabVIEW to control the four-truss structure. The system's performance is analyzed, with specific attention to both transient and steady-state behavior.

Current attempts to build fast, efficient, and maneuverable underwater vehicles have looked to nature for inspiration. However, they have all been based on traditional propulsive techniques, i.e. rotary motors. In the current study a promising and potentially revolutionary approach is taken that overcomes the limitations of these traditional methods-morphing structure concepts with integrated actuation and sensing. Inspiration for this work comes from the manta ray (Manta birostris) and other batoid fish. These creatures are highly maneuverable but are also able to cruise at high speeds over long distances. In this paper, the structural foundation for the biomimetic morphing wing is a tensegrity structure. A preliminary procedure is presented for developing morphing tensegrity structures that include actuating elements. A shape optimization method is used that determines actuator placement and actuation amount necessary to achieve the measured biological displacement field of a ray. Lastly, an experimental manta ray wing is presented that measures the static and dynamic pressure field acting on the ray's wings during a normal flapping cycle.

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 V_pp 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 describes metal based active or multifunctioal structural material systems suitable for smart structures developed by simple and innovative methods without using sophisticated and expensive actuator/sensor materials. The following topics are mainly examined: (1) the proposed active material based on SiC/Al composites was fabricated and its actuation was examined by fundamental experiments to investigate the effect of fiber distribution on maximization of deformation, reproducibility of deformation during heating cycles, the effect of fiber length on thermal deformation, and some other aspects, (2) a nickel based active composite aiming at high temperature use was fabricated and its workable temperature was investigated, and (3) a multifunctional aluminum-matrix composite was made by embedding Ti oxide/Ti composite fiber in an aluminum matrix active composite for generation of heat for actuation and sensing temperature/deformation.

An active approach for initiating rigidization in carbon-fiber reinforced polymer (CFRP) thermosets links controllable mechanical stiffening to inherent electrical resistivity. With direct applications toward the rigidization of ultra-lightweight, inflatable space structures, temperature-controlled resistive heating is used to create oncommand rigidization. As required by the on-orbit conditions in space, flexible, rigidizable structures demand stable and space-survivable materials that incorporate techniques for providing shape control and structural stiffening. Methods currently employed to achieve a mechanical hardening include many passive techniques: UV curing, sub-T_g hardening, and hydro-gel evaporation. The benefits of a passive system (simplicity, energy efficiency) are offset by their inherent lack of control, which can lead to long curing times and weak spots due to uneven curing. In efforts to significantly reduce the transition time of the composite from a structurally-vulnerable state to a fully-rigidized shape and to increase control of the curing process, an active approach is taken. Specifically, temperature-controlled internal resistive heating initiates thermoset curing in a coated carbon fiber composite to form an electrically-controlled, thermally-activated material. Through controlled heating, this research examines how selective temperature control can be used to prescribe matrix consolidation and material rigidization on two different thermosetting resins, U-Nyte Set 201A and 201B. Feedback temperature control, based on a PID control algorithm, was applied to the process of resistive heating. Precise temperature tracking (less than 1.1°C RMS or ±3.3% error) was achieved for controlled sample heating. Using samples of the thermoset-coated carbon-fiber tow, composite hardening through resistive heating occurred in 24 minutes and required roughly 1 W-hr/inch of electrical energy. The rigidized material was measured to be 14-21 times stiffer in bending than the uncured material. In addition, the cure completion of the resin was measured through differential scanning calorimetry (DSC).

A theoretical model is developed for the magnetoelectric (M-E) voltage coefficient α for a magnetostrictive-piezoelectric layered composite (MPLC). Three field orientations; including longitudinal, transverse, and in-plane, with two in plane geometries, 2D and 1D, are presented and studied with respect to the volume fraction of piezoelectric phase and the material properties of magnetostrictive phase. Results show that the phase volume fraction to achieve maximum M-E coupling effect is determined by the compliance of magnetostrictive phase. Higher compliance values shift α' peaks to lower piezoelectric volume fraction and weaken α' values. This study also investigates the influence of the piezomagnetic coefficient q₃₃ and the ratio q₃₃/q₃₁. For constant ratio of q₃₃/q₃₁, larger q₃₃ values increase the M-E coupling effect. On the contrary, changing the ratio of q₃₃/q₃₁ changes the relative α' values for each of the six cases. This demonstrates that the ratio q₃₃/q₃₁ strongly influences the selection of MPLC configurations to produce the largest α'.

Traditional methods used for strengthening of reinforced concrete (RC) structures, such as bonding of steel plates, suffer from inherent disadvantages. In recent years, strengthening of RC structures using carbon fiber reinforced polymer (CFRP) plates has attracted considerable attentions around the world. Most existing research on CFRP plate bonding for flexural strengthening of RC beams has been carried out for the strength enhancement. However, little research is focused on effect of residual deformations on the strengthening. The residual deformations have an important effect on the strengthening by CFRP plates. There exists a very significant challenge how the residual deformations are reduced. Shape memory alloy (SMA) has showed outstanding functional properties as an actuator. It is a possibility that SMA can be used to reduce the residual deformation and make cracks of concrete close by imposing the recovery forces on the concrete in the tensile zone. It is only an emergency damage repair since the SMA wires need to be heated continuously. So, an innovative method of a RC beam strengthened by CFRP plates in combination with SMA wires was first investigated experimentally in this paper. In addition, the nonlinear finite element software of ABAQUS was employed to further simulate the behavior of RC beams strengthened through the new strengthening method. It can be found that this is an excellent and effective strengthening method.

Control of jet noise continues to be an important research topic. Exhaust nozzle chevrons have been shown to reduce jet noise, but parametric effects are not well understood. Additionally, thrust loss due to chevrons at cruise suggests significant benefit from deployable chevrons. The focus of this study is development of an active chevron concept for the primary purpose of parametric studies for jet noise reduction in the laboratory and technology development to leverage for full scale systems. The active chevron concept employed in this work consists of a laminated composite structure with embedded shape memory alloy (SMA) actuators, termed a SMA hybrid composite (SMAHC). The actuators are embedded on one side of the middle surface such that thermal excitation generates a moment and deflects the structure. A brief description of the chevron design is given followed by details of the fabrication approach. Results from bench top tests are presented and correlated with numerical predictions from a model for such structures that was recently implemented in MSC.Nastran and ABAQUS. Excellent performance and agreement with predictions is demonstrated. Results from tests in a representative flow environment are also presented. Excellent performance is again achieved for both open- and closed-loop tests, the latter demonstrating control to a specified immersion into the flow. The actuation authority and immersion performance is shown to be relatively insensitive to nozzle pressure ratio (NPR). Very repeatable immersion control with modest power requirements is demonstrated.

In this research, the authors target on the construction of structural health monitoring system of Advanced Grid Structure (AGS) made of Carbon fiber reinforced plastic (CFRP). AGS has often been applied to aerospace structures because of the following advantages: (1) Since ribs carry only axial forces, the weakness in the transverse direction of the CFRP unidirectional laminates is negligible. (2) AGS has damage tolerance because the fracture of a rib hardly affects other ribs, namely AGS is a fail-safe structure. In this research, in order to detect existence and regions of rib fractures in AGS, we embedded multiplexed fiber Bragg grating (FBG) sensors into AGS in rib longitudinal directions for measurement of strains. Monitoring of the change in rib longitudinal strains is the most effective SHM system for AGS. In order to confirm our proposal, we carried out following discussions. First, we analytically revealed that the change in rib longitudinal strains was the most sensitive signal for damage detection because of AGS's structural redundancy. Then, we introduced a statistical outlier analysis technique into the SHM system for damage recognition. Finally, we established AGS with the SHM system and verified experimentally. The result of the test showed that damage existence and regions in AGS could be detected with the proposed SHM system.

The sensitivity and consistency of a damage index based on instantaneous phase values obtained through vibration measurements of a structure is investigated experimentally. An 'empirical mode decomposition' is performed to decompose structural vibrations into a small number of 'intrinsic mode functions' following the methodology generally known as the Hilbert-Huang Transform. Instantaneous phase information is derived through the Hilbert transform of intrinsic mode functions. The damage index is based on the idea that the difference in phase functions between any two points on a structure is altered if the structure is damaged. Experimental investigations are performed on a beam structure with varying excitations (white noise signals), damage levels, and damage locations. The damage index shows generally consistent results, but its sensitivity to damages needs improvements for practical applications.

A new technique to characterize localized linear elastic constitutive behavior within a Fiber Optic Sensor (FOS) embedded parallel to reinforcing fibers has been developed. A unit cell model has been developed with stresses anywhere within the unit cell formulated as a function of sensor strains. A slicing approach has been implemented within the unit cell to determine effective stresses within each slice of the unit cell. Different layers of the FOS are modeled using individual slices to model the stresses within a given slice. Numerical results are presented for SMF-28 FOS. The accuracy of the developed slicing based micromechanics approach has been validated by comparisons with results obtained using an established micromechanics analysis code based on the Generalized Method of Cells and a general purpose finite element technique. Effective unit cell stress results from all three models show close correlation to one another. In addition, convergence of normal stresses was also investigated with increasing volume fraction of surrounding reinforcing carbon fibers.

This paper presents recent results from an ongoing investigation on the use of non-collocated actuator/receiver pair to enable dynamic testing of a thin membrane in order to detect cracks. The current focus is on obtaining the transfer function of a Kapton membrane excited at one end by a polyvinilidine fluoride (PVDF) actuator. A receiver of identical specifications is located at the other end. The actuator operates in the d₃₁ mode which under sinusoidal excitation leads to a periodic variation in membrane tension. The paper shows that the resulting dynamics can be analyzed with the help of the Mathieu equation. As such, the frequency response of this membrane is complicated. The presence of a crack could in principle be detected by the corresponding decrease in the output voltage amplitude at the drive frequency in the Fourier transform of the output, but this was found difficult in practice. Detailed analysis of the parametrically excited dynamics with and without a crack could lead to precise and reliable signatures for healthy and cracked membranes.

The availability of inexpensive and high-resolution commercial digital video cameras has brought forth a new area of application that based on the processing of high quality of digital images. Videogrammetry is a three-dimensional measurement technique that combines the traditional photogrammetry and the computer vision technique. This technique has been previously demonstrated to provide reliable accuracy comparable to that of the traditional sensors for dynamic measurement. Potentially, the technique can measure three-dimensional deformation time history of either a few selected targets or a continuous spatial profile on a structure. In this paper, a novel technique based on videogrammetry is proposed for investigation of structural dynamic behavior, which can measure deformation with sub-pixel accuracy is first established to extract the temporal-spatial deformation of a structure. A simple modal identification method in frequency domain is then applied to extract structural vibration parameters using dynamic responses reconstructed from the image sequence. For demonstration of proof-of-concept, a lab test of identifying the free vibration of a steel cantilever beam is performed. Results have indicated that the proposed technique can achieve a good agreement with the analytical analysis, and show its significant potential for vibration-based real applications.

Acoustic emission (AE) testing is potentially a highly suitable technique for structural health monitoring (SHM) applications due to its ability to achieve high sensitivity from a sparse array of sensors. For AE to be deployed as part of an SHM system it is essential that its capability is understood. This is the motivation for developing a forward model, referred to as QAE-Forward, of the complete AE process in real structures which is described in the first part of this paper. QAE-Forward is based around a modular and expandable architecture of frequency domain transfer functions to describe various aspects of the AE process, such as AE signal generation, wave propagation and signal detection. The intention is to build additional functionality into QAE-Forward as further data becomes available, whether this is through new analytic tools, numerical models or experimental measurements. QAE-Forward currently contains functions that implement (1) the excitation of multimodal guided waves by arbitrarily orientated point sources, (2) multi-modal wave propagation through generally anisotropic multi-layered media, and (3) the detection of waves by circular transducers of finite size. Results from the current implementation of QAE-Forward are compared to experimental data obtained from Hsu-Neilson tests on aluminum plate and good agreement is obtained. The paper then describes an experimental technique and a finite element modeling technique to obtain quantitative AE data from fatigue crack growth that will feed into QAE-Forward.

The motivation for using guided acoustic waves as the sensing mechanism for large area structural health monitoring (SHM) is explained and the logic for using baseline signal subtraction as the fundamental signal processing tool is presented. In the first part of this paper, a simple experimental example is presented to illustrate how a guided wave SHM using baseline subtraction could be used to detect and locate simulated damage in a 1 m by 1.5 m by 3 mm thick aluminum plate. The experiment shows for an SHM system to be useful it must have a coherent noise floor around 40 dB lower in amplitude that the amplitude of a signal reflected from the edge of the structure. The experiment demonstrates that the sensitivity is severely limited by the stability of the baseline subtraction procedure which deteriorates rapidly over time. In the second part of the paper, the factors affecting the stability of the reference signal subtraction approach are investigated. Experimental and modeling studies on a simple test structure are presented that show that a change in temperature of a few degrees leads to coherent artifacts after baseline subtraction that are of a similar magnitude to the signals arising from defects. A possible strategy for overcoming this barrier to reliable baseline signal subtraction is then considered and shown to provide an improvement in sensitivity of around 10 dB.

Phased array can interrogate large structural areas from a single location using ultrasonic guided waves generated by tuned piezoelectric wafer active sensors that are permanently attached (embedded) to the structure. Various array parameters determine the array beamforming and steering characteristics. This paper aims to bring up several one or two dimension array designs and research on their beamforming properties and damage detection performance through both analytical simulation and laboratory experiments. The paper will firstly present the generic guided wave phased array beamforming formulation and explain how the beamforming characteristics are affected by the array parameters such as number of elements, element spacing, and steering angle. Preliminary work of implementing a one dimensional linear phase array is then followed to exemplify how our embedded ultrasonic structural radar (EUSR) scans and detects damage on the plate structures. However, such a linear array has the limitations that it has limited scanning range due to the beamforming directionality deficiency and it can only scan the 0^o~180^o range either in front of or behind it, i.e., it can not tell if the damage is in the positive or negative direction in the polar coordinates. Hence, we proposed several improved array designs including: (1) a miniaturized array using smaller PWAS; (2) an array using rectangular PWAS; (3) a cross-shaped two dimensional array; (4) a L-shaped two dimensional array. Extensive simulation work has been done to explore the beamforming and beamsteering properties of those arrays. Laboratory experiments have also been conducted to testify the arrays damage detection abilities. The results show that the miniaturized array can look into larger area and be used for damage detection of compact specimen with complicated geometry. Signal rectangular PWAS has directional rather than omnidirectional beamforming which resulting in improved beamforming of the phased array using such PWAS. Two dimensional arrays show directional beamforming within full range of 0^o ~ 360^o degrees though having limited working steering angles. We finally end up with discussion and conclusion of the arrays and some expectations for future work.

This paper presents a self-diagnostic and sensor validation procedure that performs in-situ monitoring of the operational status of piezoelectric (PZT) sensors and actuators used in structural health monitoring (SHM) applications. The sensor/actuator self-diagnostic procedure, where the sensors/actuators are confirmed to be functioning properly during operation, is a critical component to successfully complete the SHM process with large numbers of active sensors typically deployed in a structure. Both degradation of the mechanical/electrical properties of a PZT transducer and the bonding defects between a PZT patch and a host structure could be identified using the proposed procedure. First, the effects of bonding defects between a PZT patch and a host structure on high frequency SHM techniques, including Lamb wave propagations and impedance methods, have been experimentally investigated. It has been found that the effects are remarkable, modifying wave phase and amplitude, creating new wave modes, and changing measured impedance spectrum. These changes can lead to the false indications on structural conditions without an efficient sensor-diagnostic procedure. The feasibility of the proposed sensor diagnostics procedure was then demonstrated by analytical studies and experimental examples, where the functionality of surface-mounted piezoelectric sensors was continuously deteriorated. The proposed procedure can provide a metric that can be used to determine the sensor functionality over a long period of service time or after an extreme loading event. Further, the proposed procedure can be useful if one needs to check the operational status of a sensing network right after its installation.

Nastic structures are capable of three dimensional shape change using biological principles borrowed from plant motion. The plant motor cells increase or decrease in size through a change in osmotic pressure. When nonuniform cell swelling occurs, it causes the plant tissue to warp and change shape, resulting it net movement, known as nastic motion, which is the same phenomena that causes plants to angle their broad leaf and flower surfaces to face light sources. The nastic structures considered in this paper are composed of a bilayer of microactuator arrays with a fluid reservoir in between the two layers. The actuators are housed in a thin plate and expand when water from the fluid reservoir is pumped into the actuation chamber through a phospholipid bilayer with embedded active transport proteins, which move the water from the low pressure fluid reservoir into a high pressure actuation chamber. Increasing water pressure inside the actuator causes lateral expansion and axial bulging, and the non-uniform net volume change of actuators throughout the nastic structure results in twisting or bending shape change. Modifying the actuation displacement allows controlled volume change. This paper presents an analytical model of the driving and blocking forces involved in actuation, as well as stress and strain that occurs due to the pressure changes. Actuation is driven by increasing osmotic pressure, and blocking forces are taken into consideration to plan actuator response so that outside forces do not counteract the displacement of actuation. Nastic structures are designed with use in unmanned aerial vehicles in mind, so blocking forces are modeled to be similar to in-flight conditions. Stress in the system is modeled so that any residual strain or lasting deformation can be determined, as well as a lifespan before failure from repeated actuation. The long-term aim of our work is to determine the power and energy efficiency of nastic structures actuation mechanism.

A Ni-Ti-Co alloy exhibits shape memory effect, pseudo-elasticity, and these transition properties depending on the temperature when used. This paper examined a first-step application of such an alloy to an earthquake resistant structural system by making and testing a pseudo-elastic bracing system. Substructure pseudo-dynamic tests were performed to examine the behavior of pseudo-elastic bracing system during an earthquake when combined with fictitious hysteretic dampers. A pseudo-elastic bracing system is better to be used with other hysteretic elements such as a hysteretic damper. A damper provides energy dissipation within small displacement levels, and a pseudo-elastic bracing system works in turn as a back-up/fail-safe system when an accidental failure of damper or damper interface occurs, and also it helps to pull back the structure to the original position by uninstalling the damper after earthquake.

This paper describes development of high performance CFRP/metal active laminates and demonstrations of them in complicated forms. Various types of the laminates were made by hot-pressing of an aluminum, aluminum alloys, a stainless steel and a titanium for the metal layer as a high CTE material, a unidirectional CFRP prepreg as a low CTE/electric resistance heating material, a unidirectional KFRP prepreg as a low CTE/insulating material. The aluminum and its alloy type laminates have almost the same and the highest room temperature curvatures and they linearly change with increasing temperature up to their fabrication temperature. The curvature of the stainless steel type jumps from one to another around its fabrication temperature, whereas the titanium type causes a double curvature and its change becomes complicated. The output force of the stainless steel type attains the highest of the three under the same thickness. The aluminum type successfully increased its output force by increasing its thickness and using its alloys. The electric resistance of the CFRP layer can be used to monitor the temperature, that is, the curvature of the active laminate because the curvature is a function of temperature. The aluminum type active laminate was made into complicated forms, that is, a hatch, a stack, a coil and a lift types, and their actuation performances were successfully demonstrated.

Compliant mechanisms have a wide range of application in microassembly, micromanipulation and microsurgery. This article presents a low cost Flexure-Stage actuated by two SMA-wires that produces displacement in one direction in a range from 0 to 10 μm. The Flexure-Stage acts as a mechanical transform by reducing and changing the direction of the SMA actuator output displacement. The Flexure-Stage system has its application in microassembly operation and was built at cost of US$ 35 cost. The design methodology of a flexure-stage from concept design through FEA modeling and finally to construction and characterization is presented in this paper.