This paper describes the commercial applications of Metal Rubber, the first material of its kind, a self-assembled free-standing electrically conductive elastomer in biomedical, aerospace and microelectronic areas. Metal Rubber is a novel nanocomposite formed via the self-assembly processing of metal nanoparticles and elastomeric polyectrolytes. This type of processing allows for control over bulk mechanical and electrical properties and requires only ppm quantities of metal to achieve percolation. The use of nanostructured precursors also results in transparent, electrically conductive nanocomposites. Metal Rubber elastomers are being developed as electrodes, for biomedical applications; flexible interconnects for microelectronics, and sensors to detect fatigue, impact and large strain for aerospace applications. This novel material may be formed as a conformal coating on nearly any substrate or as free standing films.

Electrical, optical and hydraulic conductors are vital components of most modern engineered systems. Damage to wiring and other conductors can degrade system performance, require expensive maintenance, and may cause catastrophic failures. This paper describes some efforts at developing active methods for self-healing wiring and conductor insulation. The concept is that there may be situations where it is beneficial to use self-healing cabling. One-part and two-part self-healing systems are fabricated and tested. Localized toughening in the face of localized damage has been realized in bench top experiments.

Magnetostrictive particulate composites promises to be a revolutionary new damping solution with possible loss factors similar to current viscoelastic systems but coupled with a significantly higher modulus ~ 10GPa. Magnetostrictive particulate composites fabricated from Terfenol-D (Tb_xDy_1-xFe_1.92) particles and epoxy resin, were mechanically tested under cyclic compressive loads in an MTS load frame to determine hysteric losses, from which an approximate tanδ was derived to quantify damping performance. DMA results on the same composites corroborated the MTS results. Various off-stoichiometric compositions of Terfenol-D were studied with varying Tb composition of x = 0.35, 0.4, 0.45, 0.5, 0.75 and 1.0. Results indicated better damping with higher Tb compositions peaking at Tb=0.5.

Innovations in the use of thin film SMA materials have enabled the development of a harsh environment pressure sensor useful for combustion monitoring and control. Development of such active combustion control has been driven by rising fuel costs and environmental pressures. Active combustion control, whether in diesel, spark ignited or turbine engines requires feedback to the engine control system in order to adjust the quantity, timing, and placement of fuel charges. To be fully effective, sensors must be integrated into each engine in a manner that will allow continuous combustion monitoring (turbine engines) or monitoring of each discrete combustion event (diesel and SI engines). To date, the sensors available for detection of combustion events and processes have suffered from one or more of three problems: 1) Low sensitivity: The sensors are unable to provide and adequate signal-to-noise ratio in the high temperature and electrically noisy environment of the engine compartment. Attempts to overcome this difficulty have focused on heat removal and/or temperature compensation or more challenging high temperature electronics. 2) Low reliability: Sensors and/or sensor packages have been unable to withstand the engine environment for extended periods of time. Issues have included gross degradation and more subtle issues such as migration of dopants in semiconductor sensor materials. 3) High cost: The materials that have been used, the package concepts employed, and the required support electronics have all contributed to the high cost of the few sensor systems available. Prices have remained high due to the limited demand associated with the poor reliability and the high price itself. Ternary titanium nickel alloys, with platinum group metal substitution for the nickel, are deposited as thin films on MEMS-based diaphragms and patterned to form strain gages of a standard metal film configuration. The strain induced phase transformation of the SMA is used as a natural signal enhancement. These sensors are maintained at a temperature just in excess of the austenite finish temperature (Af). When the diaphragm is deformed by an applied pressure, the film undergoes the reversible martensite phase transformation. The fraction of the austenite transformed to martensite is a fraction of the applied pressure. The large difference in the resistivity of the two phases results in a very sensitive strain gage, and hence a pressure sensor with a very high gage factor. The combination of the thin film and the fact that the transformation is strain induced (rather than thermally induced) results in a sensor with very high response rate. In fact, the response rate of the sensor has been shown to be strictly a function of the mechanical response of the diaphragm. Unlike other sensor systems, the temperature of the SMA sensor is controlled above the temperature of the local environment. By controlling above the temperature of the environment, the sensor is largely immune to temperature fluctuations that can affect the response of other sensors. This technology has been demonstrated for a variety of target temperature regimes and a variety of pressure regimes. Sensor design and testing to date has ranged from 180C to >500C; and design pressures of 50 to 3500 psi, with higher pressures achievable. Characterization has included analysis of the response rate, the temperature sensitivity, reliability, and the effect of gross alloy changes. Sensor performance has also been evaluated in a diesel engine test cell. Ongoing work includes the sensitivity to minor composition changes, sensitivity to film thickness, and extended reliability and engine testing.

Cornerstone Research Group, Inc. (CRG) has recently demonstrated the feasibility of filament winding complex compound-curved composite shapes on shape memory polymer (SMP) mandrels. Under thermal stimuli, SMPs can exhibit a radical change from a rigid polymer to a flexible, elastic state, and then back to a rigid state again. SMP tubes were fabricated using CRG's Veriflex, a thermoset SMP resin system. The SMP tubes were raised above the transition temperature, the temperature at which the SMP becomes pliable and rubber-like and inflated inside a clamshell master metal mold with a cavity in the shape of the desired mandrel. The SMP was then cooled; the lowering of the temperature allows the SMP to become a rigid structure again, resulting in an exact replica of the cavity without the need of air pressure. A composite part was filament wound onto the SMP mandrel and after curing of the composite, the SMP mandrel is again raised above the transition temperature. This allows the mandrel to return to its memory shape for easy extraction. This paper will demonstrate and discuss the feasibility of SMP mandrels for filament winding and fiber placement composite manufacturing techniques allowing for quick, easy, and low cost mandrels that are dimensionally accurate, autoclave-tolerant, rapidly removable, and reusable .

The use of smart materials and multifunctional components has the potential to provide enhanced performance, improved economics, and reduced safety concerns for applications ranging from outer space to subterranean. Elastic Memory Composite (EMC) materials, based on shape memory polymers and used to produce multifunctional components and structures, are being developed and qualified for commercial use as deployable components and structures. EMC materials are similar to traditional fiber-reinforced composites except for the use of a thermoset shape memory resin that enables much higher packaging strains than traditional composites without damage to the fibers or the resin. This unique capability is being exploited in the development of very efficient EMC structural components for deployable spacecraft systems as well as capability enhancing components for use in other industries. The present paper is intended primarily to describe the transition of EMC materials as smart structure technologies into viable industrial and commercial products. Specifically, the paper discusses: 1) TEMBO EMC materials for deployable space/aerospace systems, 2) TEMBO EMC resins for terrestrial applications, 3) future generation EMC materials.

Continuous product development and technology integration efforts using shape memory polymers (SMPs) have uncovered a need for faster response times. As with most smart materials, SMP responds to a specific stimulus. Traditionally SMP is triggered by thermal stimulus; increasing the temperature of the SMP above a Tg will transition the polymer from a glassy state to a rubbery state. The transition is reversible upon cooling below the Tg. It has been determined that many SMP applications can be significantly enhanced with non-thermal triggering. Non-thermal triggering eliminates the need for heating mechanisms and reduces cycle time. Furthermore, it has been found that with a faster response time many new applications become viable. Previous successful attempts have been made to improve response time of SMP by increasing its thermal conductivity with various thermally conductive additives1. However, thermal heating and cooling of polymers and composites of substantial thickness, thermally conductive or not, takes time. In an effort to facilitate system integration and increase the response time of SMP, researchers at Cornerstone Research Group, Inc. (CRG) have sought to eliminate the thermal dependency of SMP by developing light-activated shape memory polymer (LASMP). In this work, monomers which contain photo-crosslinkable groups in addition to the primary polymerizable groups were developed. These monomers were formulated and cured with other monomers to form LASMP. The mechanical properties of these materials, the kinetics, and the reversibility of the light-activated shape memory effect were studied. The near-, mid-, and far-term potential of this new material technology for system level applications is discussed.

The goal of this effort was to design and prototype on advanced tie down system for the restraint of M1A1 tanks on Naval Hovercrafts. The ties were required to restrain 35,000 lbs of tensile load, interface with current craft hardware and electrical systems, as well as provide increased ease of operation as compared to current ties. The new ties were designed to accommodate the force and displacement constraints of shape memory alloy actuators, the strength of support materials, shape limitations of the assembled system, and the power limitations of energy storage and transmission devices. These tasks included the design of numerical simulations, FEA models, and plastic rapid prototypes. The functional prototype utilizes wire based SMA actuators with superelastic spring actuated power-off re-tensioning. The system was designed to utilize energy stored in batteries released remotely via RF signals provided by COT transmitters and receivers. Switching was accomplished utilizing specially designed MOSFET arrays with provisions for PWM power modulation under full SMA contraction. The system was also designed to use advanced synthetic fiber webbing as tension materials to reduce overall system weight and size.

A method to determine the moisture content from the complex impedance measurements of a parallel-plate capacitor with a single shelled or in-shell peanut between the plates, at two frequencies 1 and 5 MHz, is described here. Capacitance (C), phase angle (θ) and dissipation factor (D) of the parallel-plate system at the two frequencies were measured. Using these values in a derived empirical equation, the moisture content (mc) of the peanuts was estimated to an accuracy of within 1% of the standard air-oven value. The moisture range of the peanuts tested was between 5 and 20%. The method is rapid and nondestructive and was found earlier to be applicable in certain types of grain such as corn. The study establishes a basis for the development of a practical instrument that could be useful in the grain and peanut industry.

Sample return and in-situ sampling and analysis is one of the major objectives of future NASA exploration missions. Existing drilling techniques are limited by the need for large axial forces, holding torques, and high power consumption. Lightweight robots and rovers have difficulties accommodating these requirements. To address these key challenges to the NASA objective of planetary in-situ rock sampling and analysis, a drilling technology called ultrasonic/sonic driller/corer (USDC) was developed. The USDC uses a novel driving mechanism, transferring ultrasonic vibration to sonic frequency impacts with the aid of a free-flying mass block (free-mass). The free mass then drives the drill bit. The actuator consists of a stack of piezoelectric disks with a horn that amplifies the induced vibration amplitudes. The standard USDC is a slender device, and some times its length is too long for specific NASA missions. It is of current interest to have novel designs that reduce the length of the device. For this purpose, two novel horn designs were examined analytically. One is the flipped horn, the other is the planar folded horn. The new designs of the horn were analyzed using finite element modeling and the results allow for the determination of the control parameters that can optimize the performance of the ultrasonic horn in terms of the tip displacement and velocity. The results of the modeling are described and discussed in this paper.

The lost foam casting (LFC), or expendable pattern casting, process is employed worldwide in foundries as an efficient casting technology that offers the advantages of consolidation of components, reduced machining, and recirculation of casting mold material. Currently, many foundries develop a schedule of sand raining flow rates and flask excitation accelerations for each specific pattern through an often-lengthy trial and error procedure. During casting, a single flask acceleration measurement is typically the only measurement by which the sand compaction is monitored. The current research focuses on developing an array of measurement tools to be used in measuring parameters critical to the sand compaction stage of the lost foam casting process to aid in the development of filling and vibration schedules as well as to provide additional inline measurements during foundry operation. In particular, the study focuses on the use of minimally intrusive transducers placed inline to provide direct feedback that can be then used in both passive and active process control.

The Boeing Company is funded by Air Force Research Laboratory (AFRL) to perform research and development activities on Structural Health Monitoring (SHM) and Assessment Techniques for Advanced Aerospace Vehicles. This effort includes two SHM aspects, i.e., on-board sensors and ground based NDE techniques. The first aspect focuses on prototyping a SHM system that integrates several different types of sensors to generate structural health information based on real-time or near real-time sensor data. The second aspect focuses on a ground system that provides a linkage between the on-board sensors and ground based NDE techniques with a prototype system capable of rapidly gathering and interpreting structural health information. They can be viewed as two parts of a SHM system that are complimentary to one another. Developing such an SHM system is intended to help advance aerospace vehicle's safety and reliability, satisfy the required turnaround time, reduce cost and cycle time in design, operation and maintenance. The primary vehicle platform considered for this program is the Space Operation Vehicle (SOV)¹, a future high speed vehicle. The baseline vehicle description will be used to determine system requirements for a SHM/NDE system and to evaluate candidate technologies throughout the technology down select process. This paper will discuss an evaluation test in which candidate sensors and NDE methods are applied to space structure components tested at a simulated flight load environment.

Visual signature suppression (VSS) methods for several classes of aircraft from WWII on are examined and historically summarized. This study shows that for some classes of uninhabited aerial vehicles (UAVs), primary mission threats do not stem from infrared or radar signatures, but from the amount that an aircraft visually stands out against the sky. The paper shows that such visual mismatch can often jeopardize mission success and/or induce the destruction of the entire aircraft. A psycho-physioptical study was conducted to establish the definition and benchmarks of a Visual Cross Section (VCS) for airborne objects. This study was centered on combining the effects of size, shape, color and luminosity or effective illumance (EI) of a given aircraft to arrive at a VCS. A series of tests were conducted with a 6.6ft (2m) UAV which was fitted with optically adaptive electroluminescent sheets at altitudes of up to 1000 ft (300m). It was shown that with proper tailoring of the color and luminosity, the VCS of the aircraft dropped from more than 4,200cm2 to less than 1.8cm² at 100m (the observed lower limit of the 20-20 human eye in this study). In laypersons terms this indicated that the UAV essentially "disappeared". This study concludes with an assessment of the weight and volume impact of such a Visual Suppression System (VSS) on the UAV, showing that VCS levels on this class UAV can be suppressed to below 1.8cm² for aircraft gross weight penalties of only 9.8%.

This paper describes a new class of flight control actuators using Post-Buckled Precompressed (PBP) piezoelectric elements. These actuators are designed to produce significantly higher deflection and force levels than conventional piezoelectric actuator elements. Classical laminate plate theory (CLPT) models are shown to work very well in capturing the behavior of the free, unloaded elements. A new high transverse deflection model which employs nonlinear structural relations is shown to successfully predict the performance of the PBP actuators as they are exposed to higher and higher levels of axial force, which induces post buckling deflections. A proof-of-concept empennage assembly and actuator were fabricated using the principles of PBP actuation. A single grid-fin flight control effector was driven by a 3.5" (88.9mm) long piezoceramic bimorph PBP actuator. By using the PBP configuration, deflections were controllably magnified 4.5 times with excellent correlation between theory and experiment. Quasi-static bench testing showed deflection levels in excess of ±6° at rates exceeding 15 Hz. The new solid state PBP actuator was shown to reduce the part count with respect to conventional servoactuators by an order of magnitude. Power consumption dropped from 24W to 100mW, weight was cut from 108g to 14g, slop went from 1.6° to 0.02° and current draw went from 5A to 1.4mA. The result was that the XQ-138 subscale UAV family experienced nearly a 4% reduction in operating empty weight via the switch from conventional to PBP actuators while in every other measure, gross performance was significantly enhanced.

This paper presents a new method used to determine the optimum group configuration of any specified number of piezoelectric actuators for vibration control of a flexible aircraft fin. A finite element model of the fin was used to obtain the frequency response function (FRF). The fitness function for optimization using a genetic algorithm was derived directly from this FRF, eliminating the need for a closed-form analytical solution. In comparison to the existing approaches, the novelty of this method is in that it allows optimization on much more complex geometries where the derivation of an analytical fitness (cost) function is prohibitive or impossible. Optimum configurations of pre-determined numbers of actuators are presented for single mode and multi-modal acceleration and displacement control criteria. Group efficiency and control authority are also examined, allowing a suitable number of actuators to be selected for any application. Actuator efficiency was higher for single mode control; however, actuation authority was much higher in multi modal control, reflecting the fact that it is desirable to select actuators that are able to exert substantial control authority over several modes.

Cornerstone Research Group, Inc. (CRG) is developing a unique adaptive wing structure intended to enhance the capability of loitering Unmanned Air Vehicles (UAVs). In order to tailor the wing design to a specific application, CRG has developed a wing structure capable of morphing in chord and increasing planform area by 80 percent. With these features, aircraft will be capable of optimizing their flight efficiency throughout the entire mission profile. The key benefit from this morphing design is increased maneuverability, resulting in improved effectiveness over the current design. During the development process CRG has overcome several challenges in the design of such a structure while incorporating advanced materials capable of maintaining aerodynamic shape and transferring aerodynamic loads while enabling crucial changes in planform shape. To overcome some of these challenges, CRG is working on integration of their shape memory polymer materials into the wing skin to enable seamless morphing. This paper will address the challenges associated with the development of a morphing aerospace structure capable of such large shape change, the materials necessary for enabling morphing capabilities, and the current status of the morphing program within CRG.

This investigation addresses basic characterization of a shape memory polymer (SMP) as a suitable structural material for morphing aircraft applications. Tests were performed for monotonic loading in high shear at constant temperature, well below, or just above the glass transition temperature. The SMP properties were time-and temperature-dependent. Recovery by the SMP to its original shape needed to be unfettered. Based on the testing SMPs appear to be an attractive and promising component in the solution for a skin material of a morphing aircraft. Their multiple state abilities allow them to easily change shape and, once cooled, resist large loads.

The search for existing or past life in the Universe is one of the most important objectives of NASA's mission. For this purpose, effective instruments that can sample and conduct in-situ astrobiology analysis are being sought. In support of this objective, a novel Ultrasonic/Sonic Driller/Corer (USDC) based mechanism has been developed to probe and sample rocks, ice and soil. The USDC consists of an ultrasonic actuator that impacts a coring or drilling bit at sonic frequencies through the use of an intermediate free-mass. The USDC can produce both a core and powdered cuttings as well as emit elastic waves into the penetrated medium. For planetary exploration, this mechanism has the important advantage of requiring low axial force, virtually no torque, and can be duty cycled to require low average power. This low axial load advantage overcomes a major limitation of planetary sampling in low gravity environments and when operating from lightweight robots and rovers. The low average power operation produces a minimum temperature rise which is important for the acquisition of biologically meaningful samples. The development of the USDC is being pursued on various fronts ranging from analytical modeling to improvements of the mechanism while seeking a wide range of applications. In this paper, the latest status of the USDC development and applications that are underway is reviewed and discussed.

Future NASA's missions include the search for past and existing life in the Universe and evidence on how the planets in the Solar system formed and evolved. In order to fulfill these goals sampling systems that meet the stringent requirements of the various environments are required to be developed. To support these objectives an ultrasonic/sonic driller/corer (USDC) device has been developed at Jet Propulsion Laboratory (JPL) to allow drilling and coring rocks for in-situ planetary analysis [Bar-Cohen et al, 2001]. The site location and method of sampling are of vital importance to scientists. Surface rocks abrasion, small depth soil drilling, and deep drilling have been proposed. It has been suggested that another possible source of mineralogical or astrobiological information can be found by exploring the sidewall of canyons. The exploration of such sites requires the development of a limbed robotic system capable of walking and climbing slopes up to and including vertical faces and overhangs. An anchor/drilling mechanism is currently under development and is being installed on each leg of the four-legged Steep Terrain Access Robot (STAR). This paper presents the modeling, design, and preliminary testing results of the USDC for use as end-effectors of walking/climbing robots.

Various design modifications were proposed for a torque actuator based on ferromagnetic shape memory alloy composites. These modifications were implemented into the design of the torque actuator, and prototypes were built and measured for their maximum torque, angle of twist, and work output characteristics. The design changes had an effect of increasing one or more of these characteristics with each iteration.

An improved version of the membrane actuator has been designed and constructed based on our previous diaphragm actuator. It consists of ferromagnetic shape memory alloy composite (FSMA) diaphragm and an electromagnet system. The actuation mechanism of the membrane actuator is the hybrid mechanism that we proposed previously. The high momentum airflow will be produced by the oscillation of the circular FSMA composite diaphragm driven by electromagnets close to its resonance frequency. This membrane actuator is designed for the active flow control technology on airplane wings. The active flow control (AFC) technology has been studied and shown that it can help aircraft improve aerodynamic performance and jet noise reduction. AFC can be achieved by a synthetic jet actuator injecting high momentum air into the airflow at the appropriate locations on aircraft wings. Due to large force and martensitic transformation on the FSMA composite diaphragm, the membrane actuator can produce 190 m/s synthetic jets at 220 Hz. A series connection of several membrane actuators is proposed to construct a synthetic jet actuator package for distributing synthetic jet flow along the wing span.

The implementation of smaller, lighter, and more agile military systems requires new actuation technologies that offer high power density in compact form factors. The Compact Hybrid Actuator Program (CHAP) is pursuing active material based, rectifying actuators to create new actuation solutions for these demanding applications. Our actuator approach is based on thin film NiTi membranes operating in parallel (high intrinsic power density, >125 kW/kg) combined with liquid rectification, MEMS passive check valves, and commercially available power electronics. Previous results demonstrated 8 micron thick membrane actuation with 150 Hz forced convection response and force output of 100N. This paper focuses on two developments critical in scaling up previous single membrane results to power levels sufficient for military applications. This first is the development of SOI MEMS fabricated microvalve arrays which exhibit high flow rate at high frequencies. The second focus area is the design, fabrication, and assembly of a form factor compact actuator. The initial prototype demonstration of this concept shows great promise for thin film NiTi based actuation both in military technologies and in other areas which demand extremely compact actuation such as embedded fluid delivery for biomedical applications.

Currently, there exist several different types of structural health monitoring (SHM) systems that are in the stage of development and/or are being tested for use in real-world applications. For a number of years, Structural Health Monitoring (SHM) systems have demonstrated feasibility in laboratory and controlled testing environments. Acellent has been developing and testing strategies to bring the SHM field to the next level. These include issues involved with system installation, calibration, reliability and connections for structures fabricated with composite materials. Composite structures are susceptible to hidden or barely visible damage caused by impacts and/or excessive loads that if unchecked may lead to lower structural reliability, higher life-cycle costs, and loss in operational capability. Current maintenance and inspection techniques for in-service composite structures can be labor-intensive and time-consuming. Utilization of an integrated sensor network system such as that developed by Acellent can greatly reduce the inspection burden through fast in-situ data collection and processing. Using a built-in network of actuators and sensors, Acellent Technologies is providing the tools required for a practical SHM system. In this paper, key development and testing issues concerning real-world implementation of the SHM system on composite structures are presented.

The authors have been developing a new lightweight composite grid structure equipped with a health monitoring system utilizing FBG (Fiber Bragg Grating) sensors for aircraft applications. A grid structure, comprising multiple interconnected ribs in a truss-like arrangement, has a very simple path of stress, which is easily detected with FBG sensors embedded in the ribs. In this study, manufacturing technology for embedding optical fibers into the grid structure was studied, in order to enable an embedded multi-point FBG sensor network. A total of 29 FBG sensors were embedded in a 525 x 550 mm test panel. A third test panel was also fabricated to evaluate effect of steering the optical fiber through the grid panel nodes. The strain data obtained from embedded FBG sensors were compared to ones from conventional strain gages in several loading conditions, which showed very good accordance. An appropriate arrangement of the grating wavelength of the embedded FBG sensors was also studied to show the feasibility a new lightweight composite grid structure with an excellent health monitoring system.

This paper describes the development and testing of a structural-acoustic sensing and alert system that continuously monitors a pipeline without the need of an external power source. This system is based on Mide's patented PowerAct conformable packaged piezoelectric actuator and sensor. These sensors are extremely sensitive with very high gain and can detect the most minute and high frequency strains. Since leaks in high-pressure gas pipes fit this description, there is currently no better sensor to apply to the specific problem. The results of this effort led to the design of a system that can sense, locate and report leaks and impacts in a buried pipeline system. This system is estimated to cost less than $400 / km of pipe. In conclusion, the results of this paper are encouraging and indicate that it is feasible to use the PowerAct sensors in a cost effective system to locate impacts and leaks in pipelines.

Packaged piezoelectric bi-morph actuators offer an alternative power source for health monitoring using localized vibrational power harvesting. Packaging piezoelectric wafers simplify the integration of piezoelectric ceramic wafers into products and improve the durability of the brittle piezoelectric ceramic material. This paper describes a model for predicting the power harvested from a resonant cantilevered beam piezoelectric power harvester across a resistive load. The model results are correlated with experimental power harvesting measurements made using a commercially available piezoelectric bi-morph actuator. Additionally, experimental power harvesting levels were determined under high root strain conditions and varying command frequencies. Finally, the power production capability of the packaged piezoelectric bi-morph generator was evaluated over millions of cycles at very high root strains levels, representative of the loads expected in an industrial application. Results from the testing indicate that packaged piezoelectric wafer products used in power harvesting devices are very reliable and well suited for harsh industrial application environments.

This paper describes the actively damped optical table developed and introduced as a standard product, ST series SmartTable(TM), by Newport Corporation. The active damping system is self-adjusting and robust with respect to changes in payload and vibration environment. It outperforms not only the broadband damped optical tables, but also the top-of-the-line tables equipped with tuned passive vibration absorbers. The maximum resonance vibration amplitudes are reduced about ten times. Additionally, the user has the benefit of being able to monitor and analyze vibration of the table by the conditioned low-noise signals from the embedded vibration sensors. Theoretical background, analysis, design rationale and experimental verification of the system are presented, with emphasis on sensor-actuator pairs architecture, signal processing and adaptive controls.

This paper reports a numerical and experimental study on a new multi mode vibration reduction concept for struts of machine tools or shafts of automotives. The example described in detail validates this new concept for high dynamic parallel kinematic struts. The structural advantages of parallel kinematic mechanisms are undisputed. However statical and dynamical bending and torsional loads must be considered during the design process of the structure and thus effect the shape of the strut geometry. The here described new actuator concept for multi mode vibration reduction is to influence these bending and torsional loads. It uses piezopatches based on the MFC technology licensed by NASA. Initial simulation and experimental tests were done at an one side clamped aluminium beam with applicated 45°-MFC's on both sides. Simulation results show, that driving the piezos in opposite direction leads to a bending deflection of the beam, driving them in the same phase leads to a torsional deflection of the aluminium beam. Experimental measurements confirm the simulation results. The benefit we get is a decreased number of actuators for multimode vibration reduction. Likewise these actuators allow the separation or selective combination of bending and torsion. This new actuation concept is not limited on beams. Further simulations for cylindrical struts result in a design of a MFC-ring with eight segments with changing fiber orientation for separation of bending and torsion on struts and shafts. The selective controlled activation of each of the segments leads to bending in x-direction, bending in y-direction or torsion.

As having ability of changing its apparent viscosity in presence of magnetic field in millisecond, magnetorheological fluids (MRF) exhibit widely potential application in devices or systems for controlling vibration and noise. In addition to shear stress strength, another import performance index of MRF is its stability under long time static state. For most applied conditions, without hard agglomeration is more important than higher shear stress strength. However, up to now, only a few reports pay attention to evaluate method of MRF's settling. This make it is difficult to optimize manufacturing technique of MRF and study its principle. A novel testing instrument, which made based on theory of that varying magnetic particle's volume content of MRF would induce its correspondingly changing of magnetic conductivity, designed and fabricated. And settling state of several MRF were tested by that instrument, factors which influence accuracy of that instrument is also discussed. Research shows that, the novel settled and laminated testing instrument (NSLTI) is potential to be used to evaluate settling stator and monitor settling process of magnetic particles. Moreover, study also shows that strength of magnetic field, position of magnetic field sensor, sensitivity of Tesla meter, type of MRF and testing time may influence accuracy of NSLTI.

High bandwidth actuation systems that are capable of simultaneously producing relatively large forces and displacements are required for use in automobiles and other industrial applications. Conventional hydraulic actuation mechanisms used in automotive brakes and clutches are complex, inefficient and have poor control robustness. These lead to reduced fuel economy, controllability issues and other disadvantages. This paper involves the design, development, testing and control of a two-stage hybrid actuation mechanism by combining classical actuators like DC motors and advanced smart material actuators like piezoelectric actuators. The paper also discusses the development of a robust control methodology using the Internal Model Control (IMC) principle and emphasizes the robustness property of this control methodology by comparing and studying simulation and experimental results.

A single small actuation system that provides high resolution [step size] of 2 nanometers (nm) over an extended range of 20 mm with consistent forces of 100 Newtons [peak values exceed 180 N] and integral power-off hold is described. Speeds of 60 mm/second can be shown but electronic efficiencies are much higher at 1 to 10 mm/s. Open- and closed-loop control is described. Progress on potential applications in adaptive optics, large optical beam control, and photonic and semiconductor test and measurement are noted. New data is presented showing ± 5-nm control of 100 Newton loads. Heat generation is estimated to be very small [110 mJ/hr] while actively holding position. Comparison of encoder and capacitance gage stability over time and temperature is discussed because it affects control in the 5-nm regime. This response can be contrasted with previous 2 kHz over 30-micrometer response for vibration or adaptive optics control. Performance of a new Class D switching amplifier that offers higher efficiencies at peak demands is described. The actuator design uses a set of three piezoelectric elements. These constitute 1100 nF of load. High speeds in the 20 to 60 mm/s range [up to 2500 Hz clamp change cycles] significantly affect power needed and design efficiencies. Alternative design options are presented with rationale for present design choices and resultant performance. The basic design allows for choices based on performance needed.

Three small, low cost piezo-hydraulic pumps have been developed. The pumps deliver up to 600 psi of blocked pressure and 338 cc/min of free flow, while the smallest weighs less than 90 grams. The pumps utilize cofired multilayer piezoelectric actuators for low drive voltages and low cost. The properties of these pumps make them suitable for distributed actuation systems where pump, control valve and hydraulic actuator are located at the point of actuation, minimizing the system weight and length of hydraulic tubing.

Mechanical actuators are integral components of many engineered systems. Many of the presently available actuator systems lack the desired stroke, power, controllability and reliability. The hierarchical actuator is a natural extension of the trend toward improving the performance of actuators through increments in geometric complexity and control. The hierarchical concept is to build integrated actuators out of a combination of smaller actuators. The smaller actuators are arranged geometrically and controlled so as to extend the performance of the total actuator into ranges that are not possible with actuators that are based on a few active elements and levels of control. Precision, speed increase, force output, load sharing, efficiency under smooth load/displacement control, smooth motion, stroke amplification/reduction and redundancy are all possible. Mechanics and mechanisms of hierarchical actuators are examined, along with a few experiments to demonstrate the operating principles.

Any future NASA mission would require protection of our planet from the risk of possibly returning uncontrolled biological materials. For this purpose, it is necessary to contain the acquired samples and destroy any potential biological materials that may contaminate the external surface of the container while protecting the sample itself for further analysis. A novel method that allows simultaneous separation, seaming and sealing using brazing (S3B) process for sample containerization and planetary protection has been conceived and demonstrated. A double wall container is used with clean inner-walls allowing brazing the container base (containing the sample) to its lid while separating it from the support mount and assuring its seal. The use of brazing materials that melt at temperatures that are higher than 500°C assures sterilization of the exposed areas that can potentially be contaminated by biological materials from Mars and other planets. The results of this study and the issues that were identified to require attention will be described and discussed.