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The article deals with the design of the control concept of the sorting conveyor device, which is controlled using a programmable logic automaton. Sensors for detecting objects are designed, and manipulation mechanisms for sorting products according to the detected properties of objects are also designed. It is possible to sort according to the material or according to the dimensions of the objects. The simulation confirms the correctness of the designed control concept. In the next part, a visualization of the simulation of the designed control concept is shown. [ABSTRACT FROM AUTHOR]

Control of laminar-turbulent transition in a swept-wing-type boundary-layer flow, subject to primary crossflow instability, is investigated using direct numerical simulations. In our previous works, we explored a direct base-flow stabilization aimed at a spanwise homogenous flow manipulation or a direct crossflow-vortex manipulation by plasma actuators. In this paper, the technique of upstream flow deformation (UFD) is applied, needing by far the least energy input. The actuators, modeled by local volume forcing, are set to excite amplified steady crossflow vortex (CFV) control modes with a higher spanwise wavenumber than the most amplified modes. The resulting nonlinear control CFVs are spaced narrower than the naturally occurring vortices and are less unstable with respect to secondary instability. They generate a beneficial mean-flow distortion attenuating the primary crossflow instability, and thus a delay of the transition to turbulence. Unlike roughness elements for UFD, the employed dielectric barrier discharge plasma actuators allow to set the force direction: Forcing against the crossflow has a direct, fundamental stabilizing effect due to a reduction of the mean crossflow, whereas forcing in the crossflow direction locally invokes the opposite due to a local increase of the mean crossflow. The differences between these settings, also with respect to forcing in streamwise direction, are discussed in detail, and it is shown that a significant transition delay can be achieved indeed with both, however with a differing efficiency and robustness. Additionally, a comparison to a set-up with an excitation of the control modes by synthetic blowing and suction is performed to clarify the role of the direct effect on the base flow. [ABSTRACT FROM AUTHOR]

To develop simulation techniques for reconstructing microdischarges in a dielectric barrier discharge (DBD) plasma actuator and analyze spanwise non-uniformity in a body force field, three-dimensional discharge plasma simulations of a DBD plasma actuator were conducted assuming step-like positive and negative applied voltages. Our study showed that to break the spanwise uniformity, some disturbances were required in the computational conditions to reconstruct the three-dimensional microdischarges, and the attachment of some minute bumps (several tens of micrometers in size) on the electrode edge allowed for the successful reconstruction of glow-type microdischarges and streamer-type filamentary discharges in the negative and positive applied voltage cases, respectively. The tentative body force field has strong spanwise non-uniformity corresponding to the plasma structure, and in addition, a spanwise directional body force also exists, especially in the streamer discharge. However, the spanwise averaged body force has the same spatial-distribution and time-evolution characteristics obtained with the two-dimensional simulation. VC 2014 AIP Publishing LLC. [ABSTRACT FROM AUTHOR]

This paper designs an active fault-tolerant control system for spacecraft attitude control in the presence of actuator faults, fault estimation errors, and control input constraints. The developed fault-tolerant control system is able to detect the actuator fault without false alarms caused by external disturbances, and also estimate the total fault effects accurately through an indirect fault identification approach, in which an auxiliary variable is utilized to build the relation between fault and system states. Once the fault identification is completed with certain degree of reconstruction accuracy, a fault-tolerant backstepping controller using the nonlinear virtual control input is reconfigured to accommodate the detected actuator faults effectively, in spite of actuator saturation limitations and fault estimation errors. Numerical simulation is carried out to demonstrate that the proposed active fault-tolerant control system is successful in fault detection, identification, and controller reconfiguration for handling actuator faults in attitude control systems. [ABSTRACT FROM AUTHOR]

This article presents a novel, passive approach to creating variable actuator recruitment in bundles of fluidic artificial muscles. The passive recruitment control approach is inspired by the functionality of mammalian muscle tissues, in which a single activation signal from the nervous system sequentially triggers contraction of progressively larger actuation elements until the required force is generated. Biologically, this behavior is encoded by differences in electrical resistance properties between smaller and larger muscle-fiber groups. The approach presented here produces analogous behavior using a uniform applied pressure to all fluidic artificial muscles while creating differential pressure responses and threshold pressures among the fluidic artificial muscles via tailored bladder elasticity parameters. A model for using elastic bladder stiffness to control an artificial muscle bundle with a single valve is explored and used to compare a bundle of fluidic artificial muscles with both low and high threshold pressure units to a single fluidic artificial muscle of equivalent displacement and force capability. The results of this analysis indicate the efficacy of using this control method; it is advantageous in cases where a wide range of displacements and forces are necessary and can increase efficiency when the system primarily operates in a low-force regime but requires occasional bursts of high-force capability. [ABSTRACT FROM AUTHOR]

Summary: Servo‐hydraulic actuators have been widely used for experimental studies in engineering. They can be controlled in either displacement or force control mode depending on the purpose of a test. It is necessary to control the actuators in real time when the rate‐dependency effect of a test specimen needs to be accounted for under dynamic loads. Real‐time hybrid simulation (RTHS) and effective force testing (EFT) method, which can consider the rate‐dependency effect, have been known as viable alternatives to the shake table testing method. Due to the lack of knowledge in real‐time force control, however, the structures that can be tested with RTHS and EFT are fairly limited. For instance, satisfying the force boundary condition for axially stiff members is a challenging task in RTHS, while EFT has a difficulty to be implemented for nonlinear structures. In order to resolve these issues, this paper introduces new real‐time force control methods utilizing the adaptive time series (ATS) compensator and compliance springs. Unlike existing methods, the proposed force control methods do not require the structural modeling of a test structure, making it easy to be implemented especially for nonlinear structures. The force tracking performance of the proposed methods is evaluated for a small‐scale steel mass block system with a magneto‐rheological damper subjected to various target forces. Accuracy, time delay, and resonance response of these methods are discussed along with their force control performance for an axially stiff member. Overall, a satisfactory force tracking performance was observed by using the proposed force control methods. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Machine Construction & Maintenance is the property of Institute for Sustainable Technologies - National Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, stabilization is presented for a networked control system with actuator saturation and network-induced delays. A method is exploited at updating steps of control signal rather than sampling steps in the networked control system under actuator saturation. A network-based controller is designed under the limitation of actuator saturation. With a cone complementary linearization approach, a presented scheme is also used to estimate the domain of attraction for the networked control system. A numerical simulation is provided to show the effectiveness and correctness of the method in this paper. [ABSTRACT FROM AUTHOR]

Structural Optimization and efficiency improvement of an electrothermal microactuator compared to its fundamental architectural design is reported in this paper. The principal component in the proposed device design is an electrothermal V-beam microactuator which is implemented to actuate a pre-stressed bistable curved beam, a switching element and thereby establishes a bistable MEMS switch. The proposed device is fabricated on SOI wafer with 10 µm thick device Si layer using SOIMUMPs(Silicon-On-Insulator Multi User MEMS Process) process with 3 masks. The optimized design provides 11.11% improvement in the actuation force and 8.81% increase in the axial displacement compared to the conventional V-beam actuator. [ABSTRACT FROM AUTHOR]

Shunt capacitive radio-frequency microelectromechanical system (RF MEMS) switches were fabricated on silicon substrate and characterized in the RF domain. Various switch typologies were obtained by three different approaches, which are: (1) the change of the bridge geometric parameters, (2) the covering of the actuator with a floating metal, and (3) the deposition of the bridge directly on the actuator. The S parameters of the fabricated switches were measured in the up and down states, observing the impact on the RF performance of the variation of the geometric parameters and the fabrication process. The electromagnetic modelling of the fabricated switches was used to interpret the measured RF behaviour, allowing to elucidate the drawbacks of the non-perfect conforming of the bridge on the actuator. Finally, the reliability of the fabricated RF MEMS switches under a bipolar voltage excitation was evaluated by cycling tests. Hence, the study presented here provides guidelines to solve some issues of the tight correlation between design, fabrication, performance, and reliability of RF MEMS switches, in view of a large-scale development of these devices. [ABSTRACT FROM AUTHOR]

The reliability and stability of hard disk drives (HDDs) is especially important as the areal recording density increasing rapidly target to 10 Tb/in in the future. The vibration of the Head Gimbals Assembly (HGA) is inevitable by internal fluid flow during operational process. In order to improve this undesirable problem, an acoustic piezoelectric transducer (PZT) actuator which can be used to transform an electric current to an acoustic pressure field, is glued on the HDD cover inner surface to generate acoustic pressure to suppress the flow-induced off-plate vibration (FIOPV) of the HGA. In this paper, a three-dimensional finite element model of HDD is built with an acoustic PZT actuator. The FIOPV of the HGA in the air and helium-filled drives are investigated by fluid-structure interaction simulation method. The acoustic pressure induced vibration (APIV) of the HGA is analyzed by acoustics-piezoelectric-structure interaction simulation method. After that, the suppressed FIOPV after superposing the APIV and the FIOPV is obtained by following the superposition principle. [ABSTRACT FROM AUTHOR]

The article focuses on a study of engineers from the U.S. Army Research Laboratory (ARL) and the University of Minnesota (UMN) on the next-generation robots that mimic the movements of invertebrates. It reports that development of 3D-printed dielectric elastomer actuator (DEA) will be helpful as printable robots.

Shape-Memory-Alloys (SMA) are suited for miniaturized drives since they possess a high specific workload and scalability. However, most SMA drives still require guidance to realize stiffness. But, there is a design approach for actuators which realize both. Here, the stiffness in the non-moving directions is achieved by the arrangement of the SMA as wire robot. This paper presents a general description of such actuators. Based on that the design of such actuators is formulated as a mathematical optimization algorithm providing a correlation between the variables for design and specification. In order to evaluate this approach, a rotary and a linear actuator are designed and experimentally investigated. [ABSTRACT FROM AUTHOR]

Purpose - This paper aims to propose preliminary design models of actuator housing that enable various geometries to be compared without requiring detailed knowledge of the actuator components. Aerospace actuation systems are currently tending to become more electrical and fluid free. Methodologies and models already exist for designing the mechanical and electrical components, but the actuator housing design is still sketchy. Design/methodology/approach - The approach is dedicated to linear actuators, the most common in aerospace. With special attention paid to mechanical resistance to the vibratory environment, simplified geometries are proposed to facilitate the generation of an equivalent formal development. The vibratory environment imposes the sizing of the actuator housing. Depending on the expected level of details and to vibration boundary conditions, three levels of modeling have been realized. Findings - This paper shows that the vibrations induced by aircraft environment are not design drivers for conventional hydraulic actuators but can be an issue for new electromechanical actuators. The weight of the latter can be optimized through a judicious choice of the diameter of the housing. Practical implications - This approach is applied to a comparison of six standard designs of linear actuator geometries after validation of the consistency of the different models. Early conclusions can be drawn and may lead to design perspectives for the definition of actuator architecture and the optimization of the design. Originality/value - This paper has demonstrated the importance of the vibratory environment in the design of linear actuator housing, especially for electro-mechanical actuators with important strokes. Developed analytical models can be used for the overall design and optimization of these new aerospace actuators. [ABSTRACT FROM AUTHOR]

Copyright of Acta Universitaria is the property of Universidad de Guanajuato/Acta Universitaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An adaptive compensation control scheme is proposed by using backstepping techniques for a class of uncertain nonlinear systems preceded by m hysteretic actuators, which exhibit unknown backlash nonlinearity and possibly experience unknown failures. An estimated smooth inverse of the actuator backlash is utilized in the controller design to compensate for the effects of the backlash and actuator failures. It is shown that the designed controllers can ensure all signals of closed-loop system bounded for any failure pattern of hysteretic actuators and tracking performance is also maintained. Simulation studies confirm the effectiveness of the proposed controller, especially the improvement of system performances. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

An orientation measurement method based on Hall-effect sensors is proposed for permanent magnet (PM) spherical actuators with three-dimensional (3D) magnet array. As there is no contact between the measurement system and the rotor, this method could effectively avoid friction torque and additional inertial moment existing in conventional approaches. Curved surface fitting method based on exponential approximation is proposed to formulate the magnetic field distribution in 3D space. The comparison with conventional modeling method shows that it helps to improve the model accuracy. The Hall-effect sensors are distributed around the rotor with PM poles to detect the flux density at different points, and thus the rotor orientation can be computed from the measured results and analytical models. Experiments have been conducted on the developed research prototype of the spherical actuator to validate the accuracy of the analytical equations relating the rotor orientation and the value of magnetic flux density. The experimental results show that the proposed method can measure the rotor orientation precisely, and the measurement accuracy could be improved by the novel 3D magnet array. The study result could be used for real-time motion control of PM spherical actuators. [ABSTRACT FROM AUTHOR]

In this paper the performance-optimized design of an electromagnetic micro-actuator for a Probe data-storage system is described. The Probe recording system considered in this study consists of a MEMS-based recording head array that can translate relative to a Ferroelectric media substrate. The probe device is slated to achieve 1 Tb/in2 recording density and a read/write data rate of 100 Mb/s while operating within a total power budget of 100 mW. Stringent requirements apply to the form-factor and packaging, power consumption, and operating environment making the design of the mechanical architecture and in particular, the actuator a challenging task. A methodology based on an analytical model framework for performance-optimal design of the actuator meeting these constraints is developed and presented. [ABSTRACT FROM AUTHOR]

In this paper, a novel concept of a thermo-mechanical MEMS actuator using aluminum thin-film heaters on a thermal oxide for electrical insulation is presented. The actuator is part of an universal tensile testing platform for thermo-mechanical material characterization of one dimensional materials on a micro- and nano-scopic scale under different environmental conditions, as varying temperatures, pressure, moisture or even vacuum and is realised in BDRIE technology. It is shown, that the actuator concept fulfills the requirements for the use in a tensile loading stage along with heterogeneously integrated nanofunctional elements, following a specimen centered approach in line with bottom-up self-assembly processes. Simulation and experiment agree very well in the thermal and mechanical domain and allow subsequent optimisation of the actuator performance. [ABSTRACT FROM AUTHOR]

In biomechanics and biorobotics, muscles are often associated with reduced movement control effort and simplified control compared to technical actuators. This is based on evidence that the nonlinear muscle properties positively influence movement control. It is, however, open how to quantify the simplicity aspect of control effort and compare it between systems. Physical measures, such as energy consumption, stability, or jerk, have already been applied to compare biological and technical systems. Here a physical measure of control effort based on information entropy is presented. The idea is that control is simpler if a specific movement is generated with less processed sensor information, depending on the control scheme and the physical properties of the systems being compared. By calculating the Shannon information entropy of all sensor signals required for control, an information cost function can be formulated allowing the comparison of models of biological and technical control systems. Exemplarily applied to (bio-)mechanical models of hopping, the method reveals that the required information for generating hopping with a muscle driven by a simple reflex control scheme is only I = 32 bits versus I = 660 bits with a DC motor and a proportional differential controller. This approach to quantifying control effort captures the simplicity of a control scheme and can be used to compare completely different actuators and control approaches. [ABSTRACT FROM AUTHOR]

Lamination under pressure at an elevated temperature is one of the steps of fabricating multilayer ceramics including multilayer actuators. It is generally assumed that during the lamination process the pressure applied, albeit within a range, has a trivial role in the ultimate behaviour of fired multilayer actuators. However, in the present work, we show that lamination pressure plays an important role in the most critical property, viz, strain response of multilayer actuators. Depending on the lamination pressure, the strain values may change more than hundred percent, though other properties like hysteresis, capacitance, tan δ and coupling coefficient remain nearly unaffected. [ABSTRACT FROM AUTHOR]

In this paper, we report a methodology, developed in the context of Smart Energy Efficient Middleware for Public Spaces European Project, aimed at exploiting ICT monitoring and control services to reduce energy usage and CO footprint in existing buildings. The approach does not require significant construction work as it is based on commercial-off-the-shelf devices and, where present, it exploits and integrates existing building management systems with new sensors and actuator networks. To make this possible, the proposed approach leverages upon the following main contributions: (a) to develop an integrated building automation and control system, (b) to implement a middleware for the energy-efficient buildings domain, (c) to provide a multi-dimensional building information modelling-based visualisation, and (d) to raise people's awareness about energy efficiency. The research approach adopted in the project started with the selection, as case studies, of representative test and reference rooms in modern and historical buildings chosen for having different requirements and constraints in term of sensing and control technologies. Then, according to the features of the selected rooms, the strategies to reduce the energy consumptions were defined, taking into account the potential savings related to lighting, heating, ventilation, and air conditioning (HVAC) systems and other device loads (PC, printers, etc.). The strategies include both the control of building services and devices and the monitoring of environmental conditions and energy consumption. In the paper, the energy savings estimated through simulation, for both HVAC and lighting, are presented to highlight the potential of the designed system. After the implementation of the system in the demonstrator, results will be compared with the monitored data. [ABSTRACT FROM AUTHOR]

Sensors and actuators are two indispensable parts in the paradigm of feedback control. Their implementation cost should be properly evaluated and constrained. In the previous work, a Petri net monitor with the least cost is synthesized through integer programming formulation. Despite its technical correctness, the existing method may lead to undesirable results when the net structure contains some shared or unshared resource places of a manufacturing-oriented net model. A necessary and sufficient condition is established to show that certain structures can lead to deadlock-prone supervisors. An efficient algorithm is developed to identify such structures. Furthermore, it is shown that if one can identify such structures at the initial stage, it is possible to achieve desirable controllers for the original systems. The theoretical correctness of the proposed algorithm is discussed. A manufacturing example is provided to illustrate the proposed approach. [ABSTRACT FROM AUTHOR]

The paper presents a novel pneumatic positioning system, designed around the concept of accurate positioning of a mechanical stopper for a pneumatic cylinder. This is performed by an electrical actuator, designed according to the high accuracy intended and the implied forces. [ABSTRACT FROM AUTHOR]

This paper presents a comb-drive actuator integrated with parylene-based flexible beams for large displacements at a low driving force. Single-crystal silicon and polysilicon are the traditional materials used for comb-drive actuators in the microeletromechanical systems industry. However, the larger Young's modulus limits the displacement at a low applied voltage. This study uses the parylene beams with the characteristic of a low modulus of the elastic comb-drive actuator as a compliant suspension to create a larger displacement (>50 μm) with smaller driving forces than that of silicon. High-aspect-ratio parylene beams can be fabricated through the deposition and removal of parylene in multiple stages on a silicon micro-trench. The proposed process uses a silicon-on-insulator wafer as the substrate to fabricate suspended silicon and parylene beams as rigid and compliant structures, respectively. The test devices of parylene- and silicon-based comb-drive actuators were fabricated with 100 pairs of comb fingers with gaps of 5 μm, and compliant beams of 15 μm in width, 2000 μm in span and 50 μm in thickness. When a driving voltage of 40 V dc was applied, the parylene-based comb-drive actuator generated a displacement of up to 55 μm, whereas the silicon-based comb-drive actuator generated a displacement of 2 μm. The parylene-based comb-drive actuator can generate about 27 times of displacement than that of silicon. This design is suitable for application in devices with large in-plane displacement and low switching speed. [ABSTRACT FROM AUTHOR]

Laser thermal adjustment as an application of laser forming in microsystems has received considerable attentions in recent years. This process is a noncontact and high precision forming method. The traditional mechanical microforming technologies for the adjustment step used in microsystem assembly are often limited in their accuracy and are also time consuming. This paper presents an analytical model for describing the in-plane deformation of actuators during laser thermal adjustment. A formula for calculating the in-plane bending angle of the actuator generated by the laser processing is derived. The proposed analytical model is demonstrated by the comparison of the predicted bending angles with the numerical and experimental results. Finally, a formula to predict the possible buckling of the actuator during the laser processing is also developed, from which one can design the opening of the actuator in order to avoid the buckling of the actuator during a heating stage of the process. [ABSTRACT FROM AUTHOR]

In this work, we designed an interactive stylus interface for touch-screen devices, the wUbi-Pen haptic stylus. The stylus has functions of providing both vibration and impact with a single actuator, and it is a stand-alone system including its own battery and communication module.We present a new interaction scheme on the graphical user interface (GUI) based on sensory feedback events for clicking, drag-and-drop, moving, sliding, highlighting, and drawing. Experiments evaluating stylus performance indicated that the haptic cues improved precise control of GUI elements. A simple interactive digital sketchbook was also implemented, which provided a variety of haptic feedback while drawing and touching objects. [ABSTRACT FROM AUTHOR]

Abstract: Actuators were developed using activated and non-activated multi-walled carbon nanotube (MWCNT)–ionic liquid (IL) gel electrodes and compared to a single-walled carbon nanotube (SWCNT)-based actuator with respect to the electrochemical and electromechanical properties. The activated MWCNT–COOH/polymer actuator surpassed the SWCNT/polymer actuator in terms of the generated strain. [Copyright &y& Elsevier]

Block copolymers are versatile designer macromolecules where a "bottom-up" approach can be used to create tailored materials with unique properties. These simple building blocks allow us to create actuators that convert energy from a variety of sources (such as chemical, electrical and heat) into mechanical energy. In this review we will discuss the advantages and potential pitfalls of using block copolymers to create actuators, putting emphasis on the ways in which these materials can be synthesised and processed. Particular attention will be given to the theoretical background of microphase separation and how the phase diagram can be used during the design process of actuators. Different types of actuation will be discussed throughout. [ABSTRACT FROM AUTHOR]

An actuator disk model which includes slipstream rotation and radial load distribution is derived. Its validity is assessed through comparisons with an isolated propeller prior to using it to rate the influence of propeller rotation on the distribution of forces over a wing. In particular, the down-between-engines concept is gauged with respect to inboard up rotation. The model uses RANS computations on a semi-span wing to compute spanwise lift and drag distributions. These distributions are analyzed together with pressure coefficient contours. [ABSTRACT FROM AUTHOR]

Abstract: This contribution deals with an energy based controller design for an under-actuated mechanical system with a hydraulic piston actuator. In particular, the example consists of a single acting piston actuator and a rigid mass between two springs. For the resulting system a static feedback control is designed based on energy consideration. Since the control algorithm requires the velocities, which are not measurable in this application, it is extended by a reduced observer. In addition, the stability of the desired equilibrium of the closed loop system is proven and the results are illustrated by simulation. [Copyright &y& Elsevier]

This paper deals with a new 3-degree-of-freedom (DOF) parallel mechanism for a flat-panel TV mounting device with two rotations and one translation. The most important operational requirements of this device are that it should support the heavy weight of the flat-panel TV and should be foldable to save space between the flat panel and the wall. An asymmetric parallel structure that has three kinematic chains with internal four-bar linkage is proposed to meet such requirements. Kinematic modeling was performed along with actuator sizing. Finally, the mechanism was developed and tested to show its effectiveness as a flat-panel TV mounting device. [ABSTRACT FROM AUTHOR]

With the aim of manipulating macroscopic objects, the possibility of improving energy conversion efficiency of light-driven actuators (LDAs) was investigated. Thermal expansion is one of the most efficient mechanisms reported so far but a rough estimation revealed that its upper limit in efficiency is ∼10-4%. Thermodynamics suggests several percent can be achieved in theory, so by using a suitable mechanism there is room for improvement. Based on those considerations we propose a LDA using a pre-tensioned wire of shape memory alloy. This design reduces the energy loss in converting the input light into mechanical motion. We demonstrated that a force larger than 1 Newton and an energy conversion efficiency of 1 percent can be achieved. [ABSTRACT FROM AUTHOR]

The nonlinearities of hydraulic systems represent an important issue for the compensator's design. The main nonlinearities of the hydraulic systems arise from friction, compressibility of the hydraulic fluid, complex flow properties, saturation and backlash. They depend on factors which are difficult to measure and to estimate online such as oil bulk modulus, viscosity and temperature. A linear model of hydraulic actuators is sufficient for some cases; however, for high performance control systems a non-linear model is required. The aim of this paper is to identify the main nonlinearities and to highlight their influence over hydraulic actuator performances. Additionally, this paper presents an experimental work on modeling of friction for a single rod hydraulic actuator. [ABSTRACT FROM AUTHOR]

In this study, we developed a small pneumatic actuator that can be used as an extracorporeal biventricular assist device. It incorporated a bellows-transforming mechanism to generate blood-pumping pressure. The cylindrical unit is 88 ± 0.1 mm high, has a diameter of 150 ± 0.1 mm, and weighs 2.4 ± 0.01 kg. In vitro, maximal outflow at the highest pumping rate (PR) exceeded 8 L/min when two 55 mL blood sacs were used under an afterload pressure of 100 mm Hg. At a pumping rate of 100 beats per minute (bpm), maximal hydraulic efficiency was 9.34% when the unit supported a single ventricle and 13.8% when it supported both ventricles. Moreover, pneumatic efficiencies of the actuator were 17.3% and 33.1% for LVAD and BVAD applications, respectively. The energy equivalent pressure was 62.78∼208.10 mm Hg at a PR of 60∼100 bpm, and the maximal value of dP/dt during systole was 1269 mm Hg/s at a PR of 60 bpm and 979 mm Hg/s at a PR of 100 bpm. When the unit was applied to 15 calves, it stably pumped 3∼4 L/min of blood at 60 bpm, and no mechanical malfunction was experienced over 125 days of operation. We conclude that the presently developed pneumatic actuator can be utilized as an extracorporeal biventricular assist device. [ABSTRACT FROM AUTHOR]

The swimming mechanism of the underwater fish-like robot, which is controlled by the giant magnetostrictive material actuator, is studied with the aid of the non-linear vibration method. A mechanics model of the robot is presented based on the relationship between the driving force and frequencies, which is controlled by external magnetic fields. The numerical results show that steady and unsteady solution of the project accord with the dynamic characteristics of tuna and pike fish, respectively. [ABSTRACT FROM AUTHOR]

Actuator arrays are planar arrangements of simple actuators that cooperate to translate and orient objects. This paper derives the equations of motion for manipulating an object in stick/slip contact with the actuators. A controller derived from kinematics considerations is presented and its stability analyzed with the multivariable circle criterion. Stability results are verified through simulation and experimental results on a 20 unit macroscopic actuator array. [ABSTRACT FROM AUTHOR]

This paper reviews various processes for manufacturing new type of robots termed “soft biomimetic robots.” Most robots are made of rigid metallic materials. But in recent years, various biomimetic robots based on soft materials and compliant parts have been developed. New manufacturing processes are required to fabricate these types of robots, and the processes include Shape Deposition Manufacturing (SDM) and Smart Composite Microstructures (SCM). Since the design of robots are limited by the available material and manufacturing processes, it is important to develop new manufacturing processes that will enable development of novel soft biomimetic robots. In this paper, various manufacturing processes which can be applied to soft robot fabrication are summarized, and features of those processes are described. Processes are divided into three categories; soft robot body fabrication, actuators for soft robots and stretchable electronics. This review provides a guideline for selecting manufacturing processes for soft robots and developing new processes that will enable new type of robots to be designed. [ABSTRACT FROM AUTHOR]

This paper presents the basic aspects regarding the development of a three fingered anthropomorphic hand (structural analysis, actuation concept, fabrication of the parts), followed by the experimental testing. [ABSTRACT FROM AUTHOR]

The problem studied here is passive fault tolerant control (FTC) for actuator faults as a result of loss of effectiveness. This FTC problem is formulated in the ‘absolute stability theory framework’. Based on this formulation, different tools from absolute stability theory are applied. Four controllers are proposed for four problem settings: (a) LTI certain plants, (b) uncertain LTI plants, (c) LTI models with input saturations and (d) non-linear affine single-input plants. The proposed controllers are tested on the hovercraft numerical example. [ABSTRACT FROM AUTHOR]

This paper presents the design of a Nonlinear Energy Sink (NES) controller and its application to active sus-pension systems in the Virtual Reality Environment. In this environment, the design engineers are immersed in an audio-visually coupled tele-operated environment whereby direct interaction with and control of the design process is achieved in real time. In this manner, the behavior of synthetic models of the full car can be monitored by literally walking around the car and adjusting the design parameters of the suspension as needed to ensure optimal performance while satisfying design and operational requirements. The control actuators which provide forces equivalent to nonlinear stiffness and damping elements are attached to the vehicle in order to actively isolate it from road excitation. The effect of the parameters of the NES controller on the vehicle performance is studied both in the frequency and time domain. The effectiveness of the NES controller is validated by numerical simulation. The robustness of the nonlinear energy pumping process is studied by varying the magnitude of road excitation. The simulation results in the Virtual Reality Environment show that under certain conditions, the nonlinear energy pumping can be induced and significant vibration isolation can be achieved. The performance of vehicle including the ride com-fort and road holding capability can be improved significantly. When the magnitude of road excitation is increased, the capacity of the NES to absorb energy from the main system is also enhanced. This is very important to achieve vibration isolation objectives. The virtual reality simulation results also show that the nonlinear NES controller performs better than the classical LQR controller particularly as the road condition becomes worst. [ABSTRACT FROM AUTHOR]

Abstract: An autonomous catamaran, based on a modified Prindle-19 day-sailing catamaran and fitted with several sensors and actuators was built to test the viability of GPS-based system identification for precision control. Using an electric trolling motor for propulsion, and lead ballast to match all-up weight, several system identification passes were performed to excite system modes and model the dynamic response. The identification process used the Observer Kalman IDentification (OKID) method for identifying a linear time invariant plant model and associated pseudo-Kalman filter. System identification input was generated using a human pilot driving the catamaran on roughly straight line passes. A fourth order discrete time model was generated from the data, and showed excellent prediction results. Using these models, linear quadratic Gaussian (LQG) controllers were designed and tested with the electric trolling motor. These controllers demonstrated excellent line-tracking performance, with error standard deviations of less than 0.15m. The wing-sail propulsion system was fitted, and these same controllers re-tested with the wing providing all propulsive thrust. Line-following performance and disturbance rejection were excellent, with the cross-track error standard deviations of approximately 0.30m, in spite of wind speed variations of over 50% of nominal value. [Copyright &y& Elsevier]

Abstract: This paper presents a systematical design and characteristic evaluation approach for constructing a one-wheeled actuator driven by one piezoelectric element. Such an actuator is of quite simple construction and equipped with a beam and one movable piezodisc, thereby giving a direct drive which can be particularly useful in applications for micro motion devices. A theoretical model of the actuator is derived based on the lateral elliptical motion, in order to predict driving frequencies of the actuator. Finite element analysis (FEA) modal patterns are employed to investigate dynamic vibration modes, driving frequencies and characteristics of the actuator. Experimental results are conducted for illustration of validity of the proposed design and analysis method, and for verification of characteristics of the one-wheeled actuator. [Copyright &y& Elsevier]

This paper solves the minimum-energy output-transition problem for dual-stage systems, such as dual-stage disk-drives, where the second actuator can be used to increase the bandwidth and precision of conventional single-actuator systems. The objective is to find optimal inputs that change the system output from an initial value to a final value during a specified output-transition time interval. The paper shows that, for dual-stage systems, inputs applied outside the output-transition time interval (i.e., pre- and postactuation) can substantially reduce the required input energy. For an experimental dual-stage system, results are presented to show that the input energy can be reduced by 65% with the use of pre- and postactuation inputs when compared to standard methods that do not use such pre- and postactuation. [ABSTRACT FROM AUTHOR]

As a major human sensory function, the implementation of the tactile sensation for the human-machine interface has been one of the core research interests for long time. In this paper, an innovative tactile display device based on the soft actuator technology is presented. Using electroactive polymer for the construction of the tactile display device, it can provide stimulation on the human skin without any additional electromechanical transmission. Softness and flexibility of the device structure, ease of fabrication, possibility for miniaturization, and low cost for mass production are the representative benefits of the presented device. Especially, the device application is open to many different purposes since the flexible structure offers the excellent adaptability to any contour of the human body. To prove its feasibility, a wearable device that can fit to the distal part of the human finger is presented and its performance is evaluated, experimentally. [ABSTRACT FROM AUTHOR]