Actuators and Sensors

A strategy for adaptive control and energetic optimization of aerobic fermentors was implemented, with both air flow and agitation speed as manipulated variables. This strategy is separable in its components: control, optimization, estimation. We optimized parameter’s estimation (from the usual KLa correlation) using sinusoidal excitation of air flow and agitation speed. We have implemented parameter’s estimation trough recursive least squares algorithm with forgetting factor. We carried separate essays on control, optimization and estimation algorithms. We carried our essays using an original computational simulation environment, with noise and delay generating facilities for data sampling and filtering.

Our results show the convergence and robustness of the estimation algorithm used, improved with use of both forgetting factor and KLa dead-band facilities. Control algorithm used in our work compares favorably with PID using the integrated area criteria for deviation between oxygen molarity and critical molarity (set point). Optimization algorithm clearly reduces energetic consumption, respecting critical molarity. Integration of control, optimization and adaptive algorithms was implemented, but future work is needed for stability. Methods were defined and implemented for stability improvement. We have implemented data acquisition and computer manipulation of air flow and agitation speed for actual fermentors.

An Emergency Response (ER) Cyber-Physical System (CPS) to avoid landslides and survey areas located on or near slopes is introduced that handles two problems: electronic waste disposal, and environmental disasters. Uncomplicated detection circuits using salvaged components can pinpoint floods in impoverished regions. CPSs simplify hazard prediction and mitigation in disaster supervision. Nonetheless, few green practices and efforts have been accomplished in this regard. Recent technical advances help landslides studies and the evaluation of suitable risk alleviation measures. This work addresses in situ meters, and cameras to observe ground movements more accurately. The ER-CPS identifies and can help mitigate landslides using techniques based on motion detection that can productively predict and monitor the zone conditions to classify it, and the landslide-related data can be transmitted to inspecting stations to lessen the erosion/sedimentation likelihood while increasing security.

This paper develops a model based on an original lumped-parameter network configuration for the thermal transient analysis of a permanent magnet synchronous motor (PMSM). The specific PMSM was designed and optimized for a demanding aerospace application. The validity of the proposed lumped-parameter model is verified by measurements carried out in a thermal chamber.

This research focuses on the development of an active rotor system capable of primary control and vibration reduction for rotorcraft.  The objective is to investigate the feasibility of a novel Trailing Edge Flap (TEF) actuation system driven by Pneumatic Artificial Muscles (PAMs).  A significant design effort led to a series of experimental apparatuses which tested various aspects of the performance of the actuators themselves and of TEF systems driven by them.  Analytical models were developed in parallel to predict the quasistatic and dynamic behavior of these systems.
Initial testing of a prototype blade section with an integrated PAM driven TEF proved the viability of the concept through successful benchtop testing under simulated M = 0.3 loading and open jet wind tunnel tests under airspeeds up to M = 0.13.  This prototype showed the ability of PAM actuators to generate significant flap deflections over the bandwidth of interest for primary control and vibration reduction on a rotorcraft.  It also identified the importance of high pneumatic system mass flow rate for maintaining performance at higher operating frequencies.
Research into the development and improvement of PAM actuators centered around a new manufacturing technique which was invented to directly address the weaknesses of previous designs.  Detailed finite element model (FEM) analysis of the design allowed for the mitigation of stress concentrations, leading to increased strength.  Tensile testing of the swaged actuators showed a factor of safety over 5, and burst pressure testing showed a factor of safety of 3.  Over 120,000,000 load cycles were applied to the actuators without failure.  Characterization testing before, during, and after the fatigue tests showed no reduction in PAM performance.
Wind tunnel testing of a full scale Bell 407 blade retrofitted with a PAM TEF system showed excellent control authority.  At the maximum wind tunnel test speed of M  = 0.3 and a derated PAM operating pressure of 28 psi, 18.8° half-peak-to-peak flap deflections were achieved at 1/rev (7 Hz), and 17.1° of half-peak-to-peak flap deflection was still available at 5/rev (35 Hz).  A quasistatic system model was developed which combined PAM forces, kinematics and flap aerodynamics to predict flap deflection amplitudes.  This model agreed well with experimental data.
Whirl testing of a sub-span whirl rig under full scale loading conditions showed the ability of PAM TEF systems to operate under full scale levels of centrifugal (CF), aerodynamic, and inertia loading.  A commercial pneumatic rotary union was used to provide air in the rotating frame.  Extrapolation of the results to 100% of CF acceleration predicts 15.4° of half-peak-to-peak flap deflection at 1/rev (7 Hz), and 7.7° of half-peak-to-peak flap deflection at 5/rev (35 Hz).
A dynamic model was developed which successfully predicted the time domain behavior of the PAM actuators and PAM TEF system.  This model includes control valve dynamics, frictional tubing losses, pressure dynamics, PAM forces, mechanism kinematics, aerodynamic hinge moments, system stiffness, damping, and inertia to solve for the rotational dynamics of the flap.
Control system development led to a closed loop control system for PAM TEF systems capable of tracking complex, multi-sinusoid flap deflections representative of a combined primary control and vibration reduction flap actuation scheme.
This research shows the promise that PAM actuators have as drivers for trailing edge flaps on active helicopter rotors.  The robustness, ease of integration, control authority and tracking accuracy of these actuators have been established, thereby motivating further research.

This paper proposes a new design of shape memory alloy (SMA) wire actuated gripper for open mode operation. SMA can generate smooth muscle movements during actuation which make them potentially good contenders in designing grippers. The principle of the shape memory alloy gripper is to convert the linear displacement of the SMA wire actuator into the angular displacement of the gripping jaw. Steady state analysis is performed to design the wire diameter of the bias spring for a known SMA wire. The gripper is designed to open about an angle of 22.5° when actuated using pulsating electric current from a constant current source. The safe operating power range of the gripper is determined and verified theoretically. Experimental evaluation for the uncontrolled gripper showed a rotation of 19.97°. Forced cooling techniques were employed to speed up the cooling process. The gripper is simple and robust in design (single movable jaw), easy to fabricate, low cost, and exhibits wide handling capabilities like longer object handling time and handling wide sizes of objects with minimum utilization of power since power is required only to grasp and release operations.

A lawnmower is a machine that uses a revolving blade or blades to cut a lawn grass. Many designs have been made, each suited to a particular purpose. Manual grass cutter has environmental issues regarding pollution's and also require the need of man power to operate and has a great maintenance to its engine. This robot is design to be environment friendly and operated by a rechargeable battery and can be describe as an intelligent robot because the micro-controller receives information from several sensors (PIR, Humidity and Bumper switches) connected to it in avoiding obstacle to ensure a neat pattern of cut and use the information to actuate the left and right motors driving the wheels and the center motor driving blade and at the same time it obeys all parameters of work and its program database. The result obtained from the test and analysis carried out shows that our development of the autonomous lawn mower from locally sourced materials is highly recommended because it is safer to use, environmental friendly, easy to operate, and fully automated.

In this paper, a newly modeled 3-D MEMS electrothermally actuated microgripper has been designed and simulated using COMSOL 4.3b based on finite element method (FEM). Electrothermal mechanism is the most widely used mechanism for providing large displacements at very small voltages. The new model is designed by combining asymmetric arm structure and a thin gold layer is inserted in the asymmetric arms which make it a typical bimorph structure. The microgripper presented here is electro-thermally actuated and optimized geometrically and materially to explore the effect of dimensional variation and material change on its performance. The in-plane, out of plane displacements, strain, stress ,current density and temperature has been analyzed and the results are discussed.

Shape control of adaptive wings has the potential to improve wing aerodynamic performance in off-design conditions. A possible way to attain this objective is to implement specific technologies for trailing edge morphing, aimed at changing the airfoil camber. In the framework of SARISTU project (EU-FP7), an innovative structural system incorporating a gapless deformable trailing edge was developed. A related key technology is the capability to emulate and maintain pre-selected target wing shapes within an established margin, enabling optimal aerodynamic performance under current operational pressure loads. In this paper, the actuation and control logics aimed at preserving prescribed geometries of an adaptive trailing edge under variable conditions are numerically and experimentally detailed. The actuation concept relies on a quick-return mechanism, driven by load-bearing actuators acting on morphing ribs, directly and individually. The adopted unshafted distributed electromechanical system arrangement uses servo-rotary actuators, each rated for the torque of a single adaptive rib of the morphing structure. The adopted layout ensures compactness and weight limitations , essential to produce a clean aerodynamic system. A Fiber Bragg Grating (FBG)-based distributed sensor system generates the information for appropriate open-and closed-loop control actions and, at the same time, monitors possible failures in the actuation mechanism.

—In this paper 1 , the actuator-sizing problem has been addressed for exoskeleton to operate effectively and smoothly. The purpose of this exoskeleton is to assist paralyzed children to move their lower limb and perform a gait motion. Motor torques are calculated by applying the quasi-static loads produced by worst-case poses to child lower limb, and also, by the aid of normalized bio-mechanical data extracted from literature. Also, a virtual model is developed using Matlab-Simulink to verify the results.

3-D printed magnetic soft magnetic helical coil actuators of iron oxide embedded polydimethylsiloxane. Abstract Soft actuators have grown to be a topic of great scientific interest. As the fabrication of soft actuators with conventional microfabrication methods are tedious, expensive, and time consuming, employment of 3-D printing fabrication methods appears promising as they can simplify fabrication and reduce the production cost. Complex structures can be fabricated with 3-D printing such as helical coils that can achieve actuation performances, which otherwise would be impossible with simpler geometries. In this study, development of soft magnetic helical coil actuators of iron oxide embedded polydimethylsiloxane (PDMS) was achieved with embedded 3-D printing techniques. Composites with three different weight ratios of 10%, 20%, and 30% iron nanoparticles to PDMS were formulated. Using iron nanoparticles with the size of 15-20 nm helps preserve viscosity of the printing material low enough to print it with a small-bore needle (30-gauge, 180 micrometers inner diameter). The hydrogel support of Pluronic f-127 bath and the ability to maintain the ratio of the printed fiber's diameter to coil diameter about 0.25 resulted in the successful fabrication and release of fabricated helical coil structures. This enabled 3-D printed structures characterized as magnetic actuators to achieve linear and bending actuation of more than 300% and 80° respectively in the case of composites 1 Preprint: Rasoul Bayaniahangar, Shahab Bayani Ahangar, Zhongtian Zhang, Bruce P.Lee, Joshua M.Pearce. 3-D printed magnetic soft magnetic helical coil actuators of iron oxide embedded polydimethylsiloxane. with 30% iron oxide nanoparticles. Moreover, it was shown that the 3-D printed helical coils with 10% iron oxide nanoparticles can be utilized as untethered soft robots capable of locomotion on 45 and 90 degrees inclines under an applied magnetic field.

An electric linear actuator is a device that converts the rotational motion of an electric motor into linear motion (push or pull movement).

An electric linear actuator can be used anywhere a machine pushes or pulls a load, raises or lowers a load, roughly positions a load, or rotates a load.

TiMOTION specializes in linear actuators and motion systems that are best suited for medical, industrial, ergonomic, and furniture applications.

Morphing aircraft concepts require powerful, compact and lightweight actuators in order to realize the significant changes in shape and aerodynamics desired. One source of inefficiency and lost performance common to all types of actuators is the mismatch between the force versus stroke profile available from the actuator and that required by the load. This work investigates a novel spiral spooling pulley mechanism that allows for kinematic tailoring of the actuator force profile to better match the force required to drive a given load. To show the impact of kinematic tailoring on actuator efficiency, a representative case study is made of a Pneumatic Artificial Muscle driven morphing camber airfoil employing the Fish Bone Active Camber concept. By using an advanced spiral pulley kinematic mechanism, the actuator force profile is successfully tailored to match that required, with an additional torque margin added to account for any unmodeled effects. Genetic algorithm optimization is used to select the geometric parameters of the spiral pulley that maximize energy efficiency of the actuator while ensuring it is able to produce the required torque levels. The performance of the optimized spiral pulley is compared to a baseline case employing an optimized circular pulley which does not alter the shape of the actuator force profile to show the performance improvement provided by the kinematic tailoring.

electrothermally actuated microgripper has been designed and simulated using COMSOL 4.3b based on finite element method (FEM). Electrothermal mechanism is the most widely used mechanism for providing large displacements at very small voltages. The new model is designed by combining asymmetric arm structure and a thin gold layer is inserted in the asymmetric arms which make it a typical bimorph structure. The microgripper presented here is electro-thermally actuated and optimized geometrically and materially to explore the effect of dimensional variation and material change on its performance. The in-plane, out of plane displacements, strain, stress, current density and temperature has been analyzed and the results are discussed.

Ionic polymer-metal composites (IPMCs) are electroactive materials that bend under an applied electric field. Existing work has typically dealt with the control of IPMC actuators themselves. In this paper we investigate the stabilization of an inverted pendulum on a cart using an IPMC actuator. Different from the traditional setting of cart- pendulum systems, we require that the voltage on the IPMC actuator stay close to zero, to prolong the actuator life and reduce power consumption. A state-space model is developed for the system, based on which an LQR controller together with an observer is designed. The proposed control scheme is able to stabilize the inverted pendulum for the entire duration of the experiment (five minutes). These results indicate that IPMC actuators hold potential for more sophisticated control applications.

Burgeoning transendoscopic procedures, such as endoscopic submucosal dissection (ESD), provide a promising means of treating early-stage gastric neoplasia in a minimally-invasive way. However, the remote locations of these lesions, coupled with their origination in the submucosal layers of the gastrointestinal tract, often lead to extreme technical, cogni-tive and ergonomic challenges which combat the widespread applicability and adoption of these techniques. Among these challenges is achieving the in vivo dexterity required to retract and dissect tissue. By leveraging workspace and force data obtained through clinical studies, we developed a modular, disposable, distally-mounted actuator (an 'active endcap') that can augment an endoscopist's distal dexterity in ways that are not achievable with the endoscope's built-in degrees-of-freedom. The device consists of a flexible articulating 'exoskeleton' manufactured via printed-circuit MEMS (PCMEMS) which engages and deflects electrosurgical tools that are passed through the endoscopic working channel. Embedded proprioceptive sensing is implemented on-board using distributed LED/phototransistor pairs and the principle of light intensity modulation (LIM). The distal degree-of-freedom is actuated using shape memory alloy (SMA) technology, and the actuation transmission system is fully contained within a 1-inch-long end cap that can be mounted on the distal end of the endoscope, thereby obviating the need for a mechanical connection to a proximal source. Proof-of-concept tests demonstrate that the actuator adds over 50 degrees of distal articulation to existing tools and can generate 450 mN of lateral force which has been clinically determined to be sufficient for performing circumferential incisions in ESD.

Conducting polymers are soft, wet and reactive gels capable of mimicking biological functions. They are the
electrochemomechanical actuators having the ability to sense the surrounding variables simultaneously. The
sensing and actuating signals are sent/received back through the same two connecting wires in these materials. The
sensing ability is a general property of all conducting polymers arises from the unique electrochemical reaction
taking place in them. This sensing ability is verified for two different conducting polymers here – for an
electrochemically generated polypyrrole triple layer bending actuator exchanging cations and for a chemically
generated polytoluidine linear actuator exchanging anions. The configuration of the polypyrrole actuator device
corresponds to polypyrrole-dodecyl benzene sulfonate (pPy-DBS) film/tape/ pPy-DBS film in which the film on
one side of the triple layer is acted as anode and the film on the other side acted as cathode simultaneously, and the
films interchanged their role when move in the opposite direction. The polytoluidine linear actuator was
fabricated using a hydrgel microfiber through in situ chemical polymerization. The sensing characteristics of these
two actuators were studied as a function of their working conditions: applied current, electrolyte concentration and
temperature in aqueous electrolytes. The chronopotentiometric responses were studied by applying square electrical
currents for a specified time. For the pPy actuator it was set to produce angular movement of ± 45º by the free end
of the actuator, consuming constant charges of 60 mC. In both the actuators the evolution of the muscle potential
along the electrical current cycle was found to be a function of chemical and physical variables acting on the
polymer reaction rates: electrolyte concentration, temperature or driving electrical current. The muscle potential
evolved decreases with increasing electrolyte concentrations, increasing temperatures or decreasing driving
electrical currents. The electrical energy consumed during reaction was a linear function of the working
temperature or of the driving electrical current and a double logarithmic function of the electrolyte concentration.
Thus, the conducting polymer based actuators exchanging cations or anions during electrical current flow is a
sensor of the working physical and chemical conditions which is a general property of all conducting polymers.

An active trailing-edge flap system for helicopter rotor blades using pneumatic artificial muscles was investigated, with the goal of generating flap deflections suitable for both vibration mitigation and primary flight control. Prior work with these actuators showed that large deflections were possible under full-scale conditions. This study developed and demonstrated an inner loop feedback controller that enables the flap to track the complex waveforms required to achieve its goal. Control algorithm development began with proportional feedback, but required the addition of a dead time compensator to reduce tracking error and increase bandwidth. The dead time compensator initially had a fixed value, though this transitioned to a variable to cope with potential changes in the dead time due to changing operating conditions. In this case, the system can continuously adjust the dead time estimate from the position error and predict future tracking error using that estimate, and adjust the control action accordingly. This approach requires no system model and no a priori information about the desired command signal. As such, it is well suited to the active rotor problem. Testing of this controller on single sine waves and complex waveforms composed of a sum of the first four odd harmonics of the rotor frequency showed good tracking for all conditions.

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We would like to invite you to join this exciting new project as a chapter contributor. Since this is a textbook, a great deal of this chapter entails a survey on the topic under the paradigm of cyber-physical systems, what can be done onboard and remotely, the distributed nature of the system and some exercises on futurology (anticipating trends can shed some light on upcoming designs). IET will bring great visibility to your work. You are welcome to suggest another topic/chapter title if you feel it would be more suitable. Each chapter should be around 20-25 pages each and can be submitted as a Word or Latex File. The IET will send you additional information (formatting, permission form, etc.) with the contributor's agreement once you have agreed to contribute to the book. Visit http:// www.theiet.org/resources/author-hub/books/index.cfm to get all information you need as a contributor to an IET research-level book. Each book is expected to have a total number of 500 printed pages (based on approximately 550 words per page with a 20% allowance for figures and tables). We have included a tentative schedule and list of topics below. If this is something you would consider, please send me the title of your chapter, a short description/abstract of the chapter content, and your full contact details. We will expect original content and new results for this book. You can, of course, reuse published material but the percentage of material reuse for the chapter should be less than 40%. The IET will run a piracy software on the full manuscript to control that you are including original material and will reject chapters who contain a large amount of already-published material so please do take this into consideration.

This chapter aims to be an introduction to the use of LCEs in Microsystems Technology and, specifically, to the integration of such smart soft materials into MEMS/MOEMS. First, the preparation—polymerization and crosslinking—and alignment of the macroscopic sample—mechanical, magnetic, electrical, surface or viscosity alignment—, as well as the main characteristics of LCEs—actuation modes and interaction of the environment—will be presented in the Sect.19.1.Finally, Sect.19.2 will be devoted to the state of the art for the integration of LCEs in Microsystems Technology in the fabrication of prototypes of MEMS/MOEMS.

This paper presents an enhanced haptic-enabled master-slave teleoperation system which can be used to provide force feedback to surgeons in minimally invasive surgery (MIS). One of the research goals was to develop a combined-control architecture framework that included both direct force reflection (DFR) and position-error-based (PEB) control strategies. To achieve this goal, it was essential to measure accurately the direct contact forces between deformable bodies and a robotic tool tip. To measure the forces at a surgical tool tip and enhance the performance of the teleoperation system, an optical force sensor was designed, prototyped, and added to a robot manipulator. The enhanced teleoperation architecture was formulated by developing mathematical models for the optical force sensor, the extended slave robot manipulator, and the combined-control strategy. Human factor studies were also conducted to (a) examine experimentally the performance of the enhanced teleoperation system w...

"Electromagnetic vibratory drives offer easy and simple
control of the mass flow of particulate and bulk materials. In
comparison to mechanical drives (pneumatics, hydraulics, or
inertial), these have a more simple construction and they are
compact, robust, and reliable in operation. The absence of
wearing mechanical parts, such as gears, cams belts, bearings,
eccentrics, or rotational actuators, makes the vibratory drives
(conveyors, bins, hoppers, feeders etc.) as most economical
equipment. Vibrations of bins or hoppers, in which the
particulate material is placed, produced by electromagnetic
linear exciter induce the movement of material particles, so that
they resemble a highly viscous liquid, and the material becomes
easier to transport and to dose. A mathematical model of
electromagnetic vibratory exciter is presented in this paper.
Based on this mathematical model is generate the simulation
circuit for analysis of vibratory exciter behavior in the stationary
and transient regimes. Simulation and experimental results and
their comparisons are exposed in this paper. Experimental
results are recorded on practically realized vibratory drive for
efficient discharge of collecting hoppers in electrostatic
precipitator plants."

"This paper presents an enhanced haptic-enabled master-slave teleoperation system which can be used to provide force feedback to surgeons in minimally invasive surgery (MIS). One of the research goals was to develop a combined-control architecture framework that included both direct force reflection (DFR) and position error-based (PEB) control strategies. To achieve this goal, it was essential to measure accurately the direct contact forces between deformable bodies and a robotic tool tip. To measure the forces at a surgical tool tip and enhance the performance of the teleoperation system, an optical force sensor was designed, prototyped, and added to a robot manipulator. The enhanced teleoperation architecture was formulated by developing mathematical models for the optical force sensor, the extended slave robot manipulator, and the combined-control strategy. Human factor studies were also conducted to (a) examine experimentally the performance of the enhanced teleoperation system with the optical force sensor, and (b) study human haptic perception during the identification of remote object deformability. The first experiment was carried out to discriminate deformability of
objects when human subjects were in direct contact with deformable objects by means of a laparoscopic tool. The control parameters were then tuned based on the results of this
experiment using a gain-scheduling method. The second experiment was conducted to study the effectiveness of the force feedback provided through the enhanced teleoperation system.
The results show that the force feedback increased the ability of subjects to correctly identify materials of different deformable types. In addition, the virtual force feedback provided by the
teleoperation system comes close to the real force feedback experienced in direct MIS. The experimental results provide design guidelines for choosing and validating the control architecture and the optical force sensor."

The use of automation technology in the world is widespread and a growing field. Automation is used expansively from software tasks to machine tasks. The ICT3 platform is a typical representation of an industrial automation setup. The objective of this project is to use LabVIEW to develop an efficient and robust, fully automated controller for the ICT3 setup to assemble widgets. The method used for the base controller was an event programming structure. The Graphical User Interface GUI was designed for ease of use and learn-time. At every clock-cycle, all the sensors where scanned for data. When the right sequence of data was read, the corresponding actuator action and program data were executed and updated respectively. On an average test cycle, the system was able to reach an accuracy of 100% on sorting pegs and rings, 95% on assembling a ring and peg, 99% in sensing which part passes through the Quality Assurance area, and a 100% in the Rejection area. The system is also able to save and load a csv file of its outputs using LabVIEWs file I/O functionality. The project demonstrated how LabVIEW can be used to program a complex controller to automate the ICT3 platform and generate its run-time results.

Pneumatic artificial muscles are a class of pneumatically driven actuators that are remarkable for their simplicity, lightweight, and excellent performance. These actuators are essentially a tubular bladder surrounded by a braided sleeve and sealed at both ends. Pressurization of the actuators generates contraction and tensile forces. Pneumatic artificial muscles have traditionally been used for robotics applications, but there has been recent interest in adapting them to a variety of aerospace actuation applications where their large stroke and force, which are realized at minimal weight penalty, create potential performance improvements over traditional technologies. However, an impediment to wide-spread acceptance of pneumatic artificial muscles is the relatively short fatigue lives of the actuators reported in the literature (typically, less than 18,000 actuation cycles before damage occurs). The purpose of this study is to develop a new construction method designed to greatly increase the number of fatigue cycles before damage occurs. The fabrication methodology employs a swaging process to provide smooth and distributed clamping of the bladder and braided sleeve components onto the end fittings. This approach minimizes stress concentrations and provides high mechanical strength, which can be experimentally validated via testing for the ultimate tensile failure load. Finite element analysis was used to refine the design of the swaged end fittings before extensive fatigue testing began. Long-term fatigue testing of the actuators under realistic operating conditions showed a substantial increase in actuator life, from a maximum of less than 18,000 cycles in previous research studies to more than 120,000,000 cycles in this study.

Microvalves, as well as pumps and sensors, are some of the most crucial components in microfluidics when the flow has to be controlled. New developments in microvalves for micro-fluidics are looking at reducing the device size, holding higher pressures, improving the time response, and ensuring the bio-compatibility of the components and the technology used for the manufacturing. The most common active microvalves for flow control are based on mechanical actuators (e.g. pneumatic, thermopneumatic, thermomechanical, piezoelectric, electrostatic, electromagnetic, electrochemical, or capillary-force actuators) in order to control/stop the flow, contain the fluid, and isolate regions in the microfl uidic device.

The influence of the uniaxial preload on the off-resonance actuation performance of piezoelectric ceramics was investigated for compressive preload values up to −80 MPa. The study was performed on soft-type lead zirconate titanate (PZT), being the most widely used piezoelectric material. The samples were analysed using the proportional loading method, which enables the simultaneous application of electrical and mechanical loads, thereby mimicking the real operation conditions over the full stress-strain range. An increase of the blocking stress and the longitudinal piezoelectric stress coefficient was observed for all the applied preload values. The optimum properties, a blocking stress of −56 MPa and a free strain of 0.23%, were obtained at a preload value of −40 MPa and electric field of 2 kV mm − 1 . This represents an increase of 16% and 20%, respectively, as compared to the values obtained at the smallest preload. In addition, the maximum work output was increased by about 28%. Finally, the results obtained at the lowest preload of −4 MPa using the proportional loading method were compared to the operational ranges determined by other methods. The comparison revealed large discrepancies between the methods, originating from the different order of the application of electrical and mechanical fields and the inherent nonlinearity of ferroelectric materials. This discrepancy results in decreased actuator performance due to impedance mismatching, demonstrating the need for accurate determination of the actuator's operational range.

Differential-damper (DD) elements can provide a high bandwidth means for decoupling a high inertia, high friction, non-backdrivable actuator from its output and can enable high fidelity force control. In this paper, a port-based decomposition is used to analyze the energetic behavior of such actuators in various physical domains. The general concepts are then applied to a prototype DD actuator for illustration and discussion. It is shown that, within physical bounds, the output torque from a DD actuator can be controlled independently from the input speed. This concept holds the potential to be scaled up and integrated in a compact and lightweight package powerful enough for incorporation with a portable lower limb orthotic or prosthetic device.

IPMCs are electroactive materials that bend in electric field. This paper describes a linked manipulator using IPMC joints. We argue that this design reduces the control complexity of an IPMC manipulator and increases the precision of the device. The design rationale stems from our theoretical work in material modeling. It suggests that when electrically decoupled short IPMC strips are connected to rigid links, the control of the IPMC manipulator, which is currently vaguely understood and highly non-linear, can be reduced to simple inverse kinematics serial chain manipulator control without the loss in efficiency. We validate our design by comparing the prototype device to a simple IPMC manipulator commonly investigated in the literature. The results show increased precision, reaction time and reachable workspace. We suggest that such a manipulator is suitable for soft and micromanipulation.

Liquid lens offers a simple solution to achieve tunable optical powers. This approach, however, suffers from deteriorated resolution at high diopters. In this study, a plano-convex liquid lens with aspherical cross-section is developed. Such configuration allows for the lens profiles at high diopters to be close to spherical shapes by alleviating the edge-clamping effects. Resolution tests of a 6mm lens with optimized asphericity exhibit improved resolutions in both center and peripheral regions at 40 and 100 diopters than the lenses with planar membranes. It shows that aspherical membranes can improve the resolving power of liquid lenses at high diopters, thus providing a new route of optimizing the imaging performance of adaptive liquid lenses for various applications.

We combine tensile strength analysis and X-ray scattering experiments to establish a detailed understanding of the microstructural coupling between liquid-crystalline elastomer (LCE) networks and embedded magnetic core-shell ellipsoidal nanoparticles (NPs). We study the structural and magnetic re-organization at different deformations and NP loadings, and the associated shape and magnetic memory features. In the quantitative analysis of a stretching process, the effect of the incorporated NPs on the smectic LCE is found to be prominent during the reorientation of the smectic domains and the softening of the nanocomposite. Under deformation, the soft response of the nanocomposite material allows the organization of the nanoparticles to yield a permanent macroscopically anisotropic magnetic material. Independent of the particle loading, the shape-memory properties and the smectic phase of the LCEs are preserved.  Detailed studies on the magnetic properties demonstrate that the collective ensemble of individual particles is responsible for the macroscopic magnetic features of the nanocomposite.

This paper describes a novel self-sensing ion-conductive polymer metal composite (IPMC) actuator. The actuator gives feedback of its own position and thereby can also be used as a position sensor. Unlike the IPMC sensors reported so far, the working principle of this actuator is based on the observation that the resistance of the IPMC metal surface electrode is correlated to the bending curvature.

Communication is the act of transferring information between entities. Existing architectural communication approaches provide solutions for data transfer from the sender to the receiver. While those solutions are targeting different domains, we can find a lot of similarities in their architectures. In this paper, we follow the interpersonal communication process principles with its communication components for defining a whole communication chain that combines the sensor actuator and data transfer items in one concept, pointing to the person to person and device to device communication similarities. We come with an approach of a methodology for the Internet of Things abstracted by the Spread-out Electronic Device concept. We consider the whole IoT as a single electronic device with cutout and broken wires and replaced with communication chains.

This paper presents a systematic framework to combine H ∞ /H 2 dynamic output feedback controller design and economic selection of sensors and actuators for continuous linear time-invariant multi-variate systems. This combined design is formulated as a Mixed Boolean Semi-Definite Programming (MBSDP) problem. Big-M reformulations are performed on the input and output matrices of the dynamic controller to yield column and row sparsity respectively. A numerical example is considered which illustrates the potential of the developed framework. The results obtained from this approach indicate a trade-off between the economic cost related to sensors and actuators and the closed-loop performance of the systems.

A  new spring shape is  designed  for a MEMS three
dimensional electrostatic actuat
or. A low spring constant in
Z direction for a thick structural layer is achieved.
Characteristic  features and challenges of this design are
described and the analytical analysis is verified  by FEM
simulations using CoventorWare
TM
. The analytical models
are derived  for two types  of serpentine  springs namely  a
square serpentine spring (SSS)
and curved serpentine spring
(CSS). The analytical results  are in very good agreement
with the simulations.

Here we report, water vapor driven actuation of polymer nanotubes, embedded in a nanoporous
membrane with one end attached to a surface deposited thin polymer layer. The nanotube composite
shows oscillatory motion when placed near water. Permeation of water vapor through these nanotube
embedded membranes is found to be direction dependent. With the water vapor as the driving force,
the actuator can lift a mass 1000 times heavier than itself with a change in relative humidity of less than
40%. The actuation mechanism arises due to efficient absorption of water molecules by polymer
nanotubes and their rapid evaporation through the surface deposited polymer layer. This actuator can be
used as artificial muscle and the direction dependent water transport may help in understanding the
activities of transmembrane channels and pumps of biological cells. With the aid of a nanowire
generator, the oscillatory motion can be used to generate electricity too.

A new liquid-crystalline elastomer-based micropillar array with pushing properties is obtained by the two-step crosslinking process, where the micropillars are oriented by uniaxial compression before the final curing. This orientation process allows the formation of a two-dimensional prolate polydomain conformation of the polymer backbone and the mesogens, and opens huge opportunities for the useof liquid-crystalline elastomers in microsystems and haptic applications.

Liquid crystal elastomers (LCE) are currently of great interest due to the conjoining of mesogenic ordering and rubber elasticity, exhibited in their large spontaneous thermally stimulated changes in shape. It has been shown that nanoparticles (nanotubes, photo-isomerisable dyes, magnetic nanoparticles.) can be incorporated into these LCE networks to create a more sensitive network to external stimuli (i.e. strain or stress, optical, electrical, electro-thermal, magnetic.). Here, we briefly summarise the current state of LCE–nanoparticle systems and explain in detail one system utilising carbon nanoparticles integrated at surfaces that may be used for electro-thermal heating of LCE systems.

Remotely controlled actuation with wireless sensorial feed-back is desirable for smart materials to obtain fully computer-controlled actuators. A light-con-trollable polymeric material is presented, in which exposure to light couples with a change in magnetic properties, allowing light signal conversion into non-volatile magnetic memory. The same material can serve, additionally, both as actuator and transducer, and allows the monitoring of its two-way elastic shape-changes by magnetic read-out. In order to tune the macroscopic magnetic properties of the material, both the reorientation of i) shape aniso-tropic ferrimagnetic nano-spindles and ii) a mechanically and magnetically coupled liquid-crystalline elastomer (LCE) matrix are controlled. These mate-rials are envisioned to have great potential for the development of innovative functional objects, for example, computer-controlled smart clothing, sensors, signal encoding, micro-valves, and robotic devices.

A novel solid propellant microthruster has been developed and used as the actuation assembly of a patented remote controlled capsule (RCC). It produces sufficient gas pressure to empty the drug reservoir within the RCC. A MEMS-based microigniter works as the critical component of the miniaturized thruster that houses the detonating agent – diazodintrophenol (DDNP) and the propellant – black powder. Ignition and combustion tests were performed to justify its feasibility and reliability. Results demonstrated that 166 mW power consumption led to one successful combustion and that complete and rapid drug release was achieved when the propellant ranged from 16 mg to 20 mg. The RCC integrated with the microthruster could provide a promising alternative for site-specific drug delivery in human GI tract.

We present MorePhone, an actuated flexible smartphone
with a thin-film E Ink display. MorePhone uses shape
memory alloys to actuate the entire surface of the display as
well as individual corners. We conducted a participatory
study to determine how users associate urgency and
notification type with full screen, 1 corner, 2 corner and 3
corner actuations of the smartphone. Results suggest that
with the current prototype, actuated shape notifications are
useful for visual feedback. Urgent notifications such as
alarms and voice calls were best matched with actuation of
the entire display surface, while less urgent notifications,
such as software notifications were best matched to
individual corner bends. While different corner actuations
resulted in significantly different matches between
notification types, medium urgency notification types were
treated as similar, and best matched to a single corner bend.
A follow-up study suggested that users prefer to dedicate
each corner to a specific type of notification. Users would
like to personalize the assignment of corners to notification
type. Animation of shape actuation significantly increased
the perceived urgency of any of the presented shapes.

A new liquid-crystalline elastomer-based micropillar array with pushing properties is obtained by the twostep crosslinking process, where the micropillars are oriented by uniaxial compression before the final curing. This orientation process allows the formation of a two-dimensional prolate polydomain conformation of the polymer backbone and the mesogens, and opens huge opportunities for the use of liquid-crystalline elastomers in microsystems and haptic applications.

Electromagnetic vibratory drives offer easy and simple control of the mass flow of particulate and bulk materials. In comparison to mechanical drives (pneumatics, hydraulics, or inertial), these have a more simple construction and they are compact, robust, and reliable in operation. The absence of wearing mechanical parts, such as gears, cams belts, bearings, eccentrics, or rotational actuators, makes the vibratory drives (conveyors, bins, hoppers, feeders etc.) as most economical equipment. Vibrations of bins or hoppers, in which the particulate material is placed, produced by electromagnetic linear exciter induce the movement of material particles, so that they resemble a highly viscous liquid, and the material becomes easier to transport and to dose. A mathematical model of electromagnetic vibratory exciter is presented in this paper. Based on this mathematical model is generate the simulation circuit for analysis of vibratory exciter behavior in the stationary and transient regi...

A linear, empirical, low-order-model was developed with the aim of describing the
evolution of a 2D vortex-pair ejected into a boundary layer from a slot-in-the-wall.
The model describes the evolution of a counter-rotating pair of Lamb-Oseen vortices in
the proximity of a wall on which a cross-flow Blasius boundary layer exits. Two inputs
from experimental measurements are used. First, the initial locations where the vortices
form and pinch-off from the excitation slot boundary layers. Second, the time evolution
of the vortex circulation in still-air. With this input, the model predicts the trajectories
and vorticity distribution during the interaction. Such a model could be a viable tool
for the development of a low-order-model to be implemented as a simplified boundary
condition in CFD simulations, with the aim of reducing the requirement to fully resolve
the vicinity of the excitation slot in active flow control simulations.

Magnetic shape-memory materials are responsive materials with a strong influence of shape changes on the magnetic properties, and vice versa. They offer access to unique applications, including wireless actuators, switches, and magnetic valves. To achieve the required mechanical-magnetic coupling, both inorganic materials and polymer-based hybrid system have been proposed. In inorganic materials, the magneto-crystalline anisotropy and the martensitic transformation are typically exploited to induce magnetic reorganization at the phase transition, but the associated elongation and device sizes, are limited to changes of about 10% and to the millimeter range, respectively, which severely limits their use in the mentioned applications. Polymer-based materials, on the other and,  are more efficiently sizeable and recover easily strains beyond 50% by magnetic stimuli. However, to achieve magnetic properties of serviceable strength, they require the incorporation of inorganic magnetic particles.