This paper describes a new type of hydraulic rotary actuator specifically developed to provide precision motion control in a very large, man rated, underwater telerobotic manipulator system. The high pressure, high torque rotary actuators are hydrostatically balanced, provide continuous rotation, constant torque output, exhibit minimal “stick-slip” and zero backlash. It is believed that the combination of features and the performance exhibited by these actuators represent an improvement in actuator technology to such an extent as to make projects previously determined unfeasible, now practical. Features of particular design value are a very large diameter through bore, and a truly modular design permitting use as an integral structural member. This paper will address design rationale, operating principles, key design features, product development highlights, an astronaut trainer case study, future development and potential applications.

The response of polymer matrix composites under combined proportional axial and torsional loading has been studied. Experiments were performed on solid cylindrical specimens of glass/vinylester and carbon/vinylester composites at a fiber volume fraction, V f equal to 50%. The specimens were loaded under displacement and rotation control in a proportional manner. The Budiansky-Fleck kinking model was specialized to the case of a solid cylindrical specimen and the predictions were compared to the experimental results. It was found that the compression strength of carbon composites is approximately a linear function of the applied rotation but in the case of glass composites the compression strength is initially unaffected due to shear. At a critical value of shear, the compression strength is seen to diminish rapidly. This suggests that the Budiansky-Fleck model might not be suitable for predicting the effect of shear on compression strength of glass fiber composites.

The low yawing natural frequency of vehicle system and/or the coupled natural frequency of driver-vehicle system is considered as a reason for vehicle fluctuation. In the case of passenger cars, it is well known that the yaw-gain-peak of vehicle system exists at 1–2 Hz and that of driver-vehicle system exists at 0.3–0.4Hz. In the case of large sized vehicle systems, I, Momiyama, reported in SAE No.892519 that the yaw-gain exists at 0.3–0.4 Hz. As this value is so close to the value of driver-vehicle system, sometimes the discussion regarding the vehicle dynamics of large sized vehicles seems to be confused. The purpose of this paper is to confirm the yawing behavior and to clarify the reason for the low yawing frequency of vehicle system. Firstly verification procedure and a 7DOF vehicle model considering the lateral and rotational motion of sprung mass, front/rear un-sprung mass and rotational motion of steering system are introduced. Secondly the lateral fluctuation running under fixed steering wheel is shown. We named this behavior “tottering”. Thirdly the yaw response test results by random steering input based upon ISO/TR8726 are shown. From the above testing and calculating analysis the existence of a low yaw-eigen value is confirmed. From the vector analysis of the low yaw-eigen value it is known the main factor of the low frequency is the low rigidity of steering with power steering system. The low rigidity is caused by the low spring constant of power steering servo-valve that has the dead zone at on-center.

We have fabricated and tested a magnetically actuated microplatform system for intravascular ultrasound imaging (IVUS). The system consists of a torsional microplatform located above a magnetic drive source. The magnetic source is fabricated on a separate wafer and is made up of a pair of U-shaped permalloy yokes with surrounding coils. Two Ni bars on the ends of the microplatform complete two magnetic circuits that are individually activated to tilt the corresponding side of the microplatform. Experiments show that the microplatform can rotate through a mechanical-scan angle of 14.8°. The initial magnetic source design requires a dc current of 1.48A to achieve this rotation, which can be substantially reduced by replacing the single-turn coils with dual-layer multiturn coils. The magnetically actuated microplatform system could be built at lower cost and provide greater operational flexibility than are available with present-day state-of-the-art IVUS systems.

This paper reports a high-aspect-ratio, silicon-based vertical comb drive used to actuate a micromirror. The large displacement is achieved by the curled-up comb drives. This high-aspect-ratio vertical comb drive uses the vertical capacitance gradient of the sidewall capacitor existing between comb fingers. The electrical isolation is realized by using the undercut of the deep Si etch. The 1 mm by 1 mm micromirror is made of an approximately 40 μm-thick single-crystal silicon membrane with aluminum coated on the surface. The mirror has a peak-to-peak curling of 0.5 μm. The mechanical rotation angle of the mirror is ±5°. The fabrication process is compatible with standard CMOS processes, and there is no need for wafer bonding and accurate front-to-backside alignment. Such capability has potential applications in optical switches, optical scanners, interferometric systems, and vibratory gyroscopes.

A laser opto-microactuator with four flat blades made of aluminum or Pyrex glass plates is proposed in this paper. The effects of the heat conductivity of the actuator materials on rotation phenomena are discussed. Through molecular gas dynamics effects, the actuator is rotated upon irradiation by an argon-ion laser beam. The blade surfaces of the actuator were coated with carbon black powder to absorb laser beam power and heat the surfaces. Three kinds of blades, noncoated, single-side-coated and both-sides-coated blades, were manufactured. The rotation rate of the actuator with both surfaces of one blade coated with the powder is faster than that of the actuator with only one surface coated with the powder because the total amount of radiation from the both-sides-coated surface is greater than that of a single-side-coated surface.

A numerical study is performed to investigate thermal transport phenomena in circular Couette flow in a concentric annulus, in which an axially rotating inner cylinder and stationary outer cylinder are strongly heated under the same heat flux condition. The anisotropic t 2 ¯ - ε t heat-transfer model together with the anisotropic k-ε turbulence model is employed to determine thermal eddy diffusivity. When the inner cylinder is at rest, the turbulent kinetic energy and temperature variance substantially diminish over the whole annular cross-section along the flow, resulting in laminarization, i.e., a deterioration in heat-transfer performance at the inner and outer cylinder walls. In contrast, a substantial reduction in the turbulent kinetic energy and temperature variance in the laminarizing flow is suppressed in the presence of inner core rotation. In other words, inner core rotation contributes to the suppression of laminarization in a strongly heated gas flow. These characteristics in thermal fluid flow with temperature-dependent thermal property are summarized in the form of dimensionless heat flux parameter versus inlet Reynolds number with the Taylor number, as the parameter.

An offset planetary pump fabricated in five-level polysilicon surface micromachining is introduced. The pump consists of a ring gear enclosing two planetary gears and an offset sun gear, which generates pumping due to its eccentric rotation. The pump is driven by an electrostatically actuated comb-drive microengine and mechanical power is transmitted to the ring gear through a micro gear train. The paper presents a derivation of pump capacity and the detailed design of its mechanical elements, demonstrating the implementation of relatively advanced mechanical functions in multi-level surface micromachining, including axial roller bearing support, fluidic seal and planetary gear transmission.

Magnetic fields have been widely used in industry to enhance the performance of crystal growth processes. However, no attempts have been made at applying optimization strategies to effect optimal enhancements. Here, a mathematical formulation and computational techniques are presented to describe optimal control and design strategies for the suppression of turbulent motions in the melt and the minimization of temperature gradients in the crystal in Czochralski crystal growth processes. It is shown that an axial magnetic field can effectively suppress convection in Czochralski growth of silicon. Other control parameters such as crystal and crucible rotation rates are found to be less effective.

Gas annular seals are commonly adopted for leakage control in turbomachinery applications. Scallop seal is an representative example of damper seals, and is attractive from rotordynamic stability viewpoint. To understand flow physics in such seals a computational analysis is developed to study compressible, turbulent flow in it. The following issues are addressed: (i) validation of results obtained using periodic boundary conditions accounting for turbulent and compressible flows, (ii) effect of the rotor rotation and inlet swirl ratio on flow development in the seal, (iii) extrapolation of the full-length results from limited periodic simulations, and (iv) breakdown of the friction factor on contributing pressure and shear stress components. The computational techniques presented can help address the design related issues more economically, and the findings offer insight into the fluid physics associated with a scallop seal.

In this paper the problem of frost growth within the narrow flow passages of a regenerative rotary wheel is formulated. Frost growth is assumed to occur for the portion of the wheel subject to warm humid airflow. While the wheel is subject to cold dry airflow the frost is cooled but no frost grows. This cyclic frost growth and cooling process is continued with each wheel rotation. An analytical and numerical model is developed to simulate the frost growth over one to two hours while the wheel rotates at speeds from 5 to 35 rpm.

Thin films of dielectric materials are used as insulating layers in microelectronic systems, including integrated circuits and printed circuit boards. Polymer and spin-on-glasses are widely used as coatings and interlevel dielectrics. The dielectric permitivity and loss are the electrical properties of most interest. However, characterization and optimization of the mechanical properties is essential to the successful implementation and usage of these insulators. In this presentation, thin-film structures for measuring direction-dependent properties (dielectric constant, elastic modulus, and coefficient of thermal expansion), and nano-indentation results on spin-on-glass materials will be presented. Significant improvement in the fracture toughness of nanoporous methylsilsesquioxane glass films has been demonstrated upon introduction of porosity into the films.

Boeing-SVS has developed an integrated modeling tool, Zelink, which effectively combines three commercial standard codes, Zemax, Simulink and Nastran, to predict the effect of quasistatic and dynamic disturbances on optical metrics of interest in optical space structures. Examples of optical metrics are time-varying wavefront error, point spread functions and predictions of image degradation. A simulation might involve specification of a slew angle and prediction of time-varying wavefront error. Different command shaping and attitude control techniques might be evaluated with respect to their ability to minimize wavefront error. Implementation of such simulations has shown significant dependence of simulation results on the structural modeling approach. In particular, one approach may introduce errors in the optical metric of interest, where another approach may avoid errors. The sensitivity of the optical metric is related to the necessity of maintaining the optical prescription when there is no structural deformation. A quasistatic rotation of the space structure should not significantly distort the optical prescription, since there is almost no structural deformation associated with this maneuver. This paper discusses structural modeling approaches and makes recommendations specific to optical space structure simulations.

The Bennett linkage is a 3D over-constrained linkage consisting of four pieces with the axes of rotation neither parallel nor concurrent. In this paper, we present the result of our investigation of whether the Bennett linkage can achieve the highest expansion/packaging ratio for the purpose of using it as basic units of large foldable structures. Based on the conditions of compact folding and maximum expansion we have proved that special forms of the Bennett linkage exist which enables the mechanism to be folded to a bundle. Under certain circumstance, the said forms also allow the mechanism to be flattened (expanded) to a rhombus. Hence, effective deployable element can be created from the Bennett linkages. This work has paved the way for using such a 3-d mechanism as basic construction unit for large deployable structures.

This paper is a discussion of a numerical simulation and a numerical stability study of the dynamics of a paper machine roll grinding process with an additional time delay effect, which is originated from a shape error trace on the surface of the roll under grinding. The simulation model presents the dynamic interaction between the roll and the grindstone during the process, the lateral deformations of the roll and the torsional rigid body vibration system of the roll and the grindstone with its drive. The normal and tangential forces of the grinding contact based on the wear theory and the driving torques of the roll and the grindstone with PD-controllers are considered. The mechanical model of the roll is described as a simply supported continuous beam element expressed in an eigenvector basis and in rotating coordinates. The time delay equation is based on the classical linear time delay theory with a constant delay. The numerical simulations conducted in time domain provide a view to observe the dynamic behavior and the stability of this grinding process and a tool for the design, analysis and verification of industrial roll grinding measurements in the future.

We conducted studies using micropatterned substrates to elucidate how cell shape and geometric confinement regulates the inter- and intracellular signaling pathways required for cell motility. When cells were cultured on individual cell-sized square adhesive islands coated with ECM, they extend to the edge of the island and assume a square shape. When these cells were stimulated with growth factors, they preferentially extended lamellipodia from the corners versus the sides. This process was mediated by myosin-generated isometric tension that induced tight spatial localization of Rac in the corners. When two or three capillary endothelial cells are constrained to a fibronectin (FN) island, coordinated cell migration results in stable rotation of the entire system about its center. Thus, the emergent pattern is due to the coordinated migration behavior of the cells. These observations suggest that ECM-induced mechanotransduction potentiates compartmentalized signaling pathways and the multicellular organization required of tissue morphogenesis.

This paper proposes an inverse dynamic approach to determie the required actuating torque and force for a planar flexible-link manipulator with revolute-prismatic joints such that its end-point follows a given trajectory. The formulation includes all of the non-linear terms due to large rotation of the links. Since one of the joints is prismatic, the resulting system of equations is time varying too. The results show that by applying actuating loads found by the proposed algorithm, the tracking error becomes smaller than that resulting from actuating loads obtained based on rigid link modeling.

In this paper a finite element model of a rotating paper machine roll for nip unit rolling contact analyses is discussed. This work presented here is based on the earlier work of the authors presented in [1] and [2]. The major motivations for developing a tailored FE-model including the large spin rotation are firstly to include the complex vibration phenomena as the shell vibrations of the roll structure in the analyses and secondly to reduce the computational costs of the numerical simulations due to the large number of degrees of freedom. The approach used is the use of the modal analysis i.e. to express the dynamics of the roll in terms of the lowest eigenmodes. The equations of motion are at first written in the rotating coordinates and then in addition to this the equations are expressed by using the modal coordinates. Numerical tests executed show that this modeling technique reduces computational costs significantly. Furthermore, use of the (semidefinite) eigenmode basis maintains the vibration characteristics of the roll structure. For verification purposes a test model was constructed and these simulation results were compared to the standard geometrically non-linear finite element analysis.

During flexion/extension, of the head-neck system, cervical spine undergoes a stepwise motion from the upper to lower regions with a specific time lag. Motion of each vertebrae is composed of a translation and a rotation with respect to lower vertebrae, which may be considered as an absolute rotation about an axis called Instantaneous Axis of Rotation (IAR). Location of this axis is different between normal, and degenerated spines. In this research intersegmental force-moments are evaluated and compared in normal, degenerated, and fused subjects employing a biomechanical model of head-neck system based on IAR’s concept and the results are presented.

A compliant tower in the ocean environment is modeled as a beam undergoing coupled transverse and axial motion. The beam is supported by a torsional spring and has a point mass at the other end. It is assumed that the strains are small but the rotation is moderate compared to the strain so that the equations of motion for the axial and transverse motion are nonlinearly coupled. The nonlinear coupled equations of motion are derived here using Hamilton’s principle. The forced responses due to random waves are observed here. The responses are obtained numerically using the finite difference approach.