Actuators

Camless internal combustion engines offer improvements over traditional engines in terms of torque performance, reduction of emissions, reduction of pumping losses and fuel economy. Theoretically, electromagnetic valve actuators offer the highest potentials for improving efficiency due to their control flexibility. For real applications, however, the valve actuators developed so far suffer from high power consumption and other control problems. One key point is the design of the reference trajectory to be tracked by the closed loop controller. In this brief, a design technique aimed at minimizing power consumption is proposed. A constrained optimization problem is formulated and its solution is approximated by exploiting local flatness and physical properties of the system. The performance of the designed trajectory is validated via an industrial simulator of the valve actuator.

We report on our empirical studies of a new controller for a two-link brachiating robot. Motivated by the pendulum-like motion of an ape's brachiation, we encode this task as the output of a "target dynamical system." Numerical simulations indicate that the resulting controller solves a number of brachiation problems that we term the "ladder," "swing-up," and "rope" problems. Preliminary analysis provides some explanation for this success. The proposed controller is implemented on a physical system in our laboratory. The robot achieves behaviors including "swing locomotion" and "swing up" and is capable of continuous locomotion over several rungs of a ladder. We discuss a number of formal questions whose answers will be required to gain a full understanding of the strengths and weaknesses of this approach.

Background • Approaches to IP integration of WSNs so far: Pure TCP/IP solutions: sensor nodes implement the TCP/IP stack (or a compatible set of protocols such as 6LoWPAN in 802.15.4 networks); and Gateway solutions: System Architecture and Networking PAGE 3 6/30/2010 • One node acts as an application layer gateway (e.g. base station), to make the lower layer protocols from both networks (e.g. TCP/IP, IEEE 802.15.4) transparent and to route information. • Sensor nodes implement the TCP/IP stack (or a compatible protocols such as 6LoWPAN in 802.15.4 networks)

This paper aims to develop and validate an ANSYS finite element model to predict both the cured shape and snap-through of unsymmetric bistable laminates actuated by piezoelectric macro fibre composites attached to the laminate. To fully describe piezoelectric actuation the three dimensional compliance [s ij ], piezoelectric [d ij ] and relative permittivity [ε ij ] matrices were formulated for the macro fibre actuator. The deflection of an actuated isotropic aluminium beam was then modelled and compared to experimental measurements to validate the data. The model was then extended to bistable laminates actuated using macro fibre composites. Model results were compared to experimental measurements of laminate profile (shape) and snap-through voltage. The modelling approach is an important intermediate step toward enabling design of shape-changing structures based on bistable laminates.

In recent years, a few articles describing the use of neural networks for nonlinear active control of sound and vibration were published in this journal. Using a control structure with two multilayer feedforward neural networks (one as a nonlinear controller and one as a nonlinear plant model), steepest descent algorithms based on two distinct gradient approaches were introduced for the training of the controller network. The two gradient approaches were sometimes called the filtered-x approach and the adjoint approach. Some recursive-least-squares algorithms were also introduced, using the adjoint approach. In this paper, an heuristic procedure is introduced for the development of recursive-least-squares algorithms based on the filtered-x and the adjoint gradient approaches. This leads to the development of new recursive-least-squares algorithms for the training of the controller neural network in the two networks structure. These new algorithms produce a better convergence performance than previously published algorithms. Differences in the performance of algorithms using the filtered-x and the adjoint gradient approaches are discussed in the paper. The computational load of the algorithms discussed in the paper is evaluated for multichannel systems of nonlinear active control. Simulation results are presented to compare the convergence performance of the algorithms, showing the convergence gain provided by the new algorithms.

This paper introduces biohybrid microsystems actuated by cardiomyocytes, such as microcantilever, microrobot, and micropump. The microfabicated biohybrid microcantilever can measure the contractile force of self-organized cardiomyocytes. The microcantilever is made of a biocompatible PDMS substrate, using a simple microfabrication technique and a specially designed 3D micromolding aligner. The contractile force of the cardiomyocytes makes a bending displacement of the microcantilever. Conversely, from the displacement, we can estimate the contractile of the cardiomyocytes on the microcantilever. The bending motion of the microcantilever can be applied as a biohybrid actuator of microrobot. We have developed a novel method to fabricate a crab-like microrobot that can actuate for a long period under a physiological condition. The microrobot consists of three separate front and rear legs which have a shape of the microcantilever. The performance of our crab-like microrobot was measured at an average velocity of 100 μ m/s, and the estimated total distance it traveled was 50 m for a one-week period. Finally, a micropump actuated by the self-beating cardiomyocytes is fabricated and the pumping performance is demonstrated.

This paper studies the grasp stability of two classes of threephalanx underactuated fingers with transmission mechanisms based on either linkages or tendons and pulleys. The concept of underactuation in robotic fingers-with fewer actuators than degrees of freedom (DOF)-allows the hand to adjust itself to an irregularly shaped object without complex control strategy and sensors. With a n-phalanx finger, n contacts (one for each phalanx) are normally required to statically constrain the finger. However, some contact forces may be lacking due to either the transmission mechanism, or simply the object size and position. Thus, one may define an i th order equilibrium, when the finger is in static equilibrium with i missing contacts. In this paper, the case for which n = 3 is studied with a particular emphasis on the cases for which i = 1 and i = 2. The fact that some contact forces do not appear or are negative, can lead in some cases to the ejection of the object from the hand, when no equilibrium configuration is achieved.

ence on Roborics and A U~O I W K 2. S h i l l e r S. 3ubowsky l a s e a r c h Assisunc Pro terror The mtioa of c u r r e n t i n d u s t r i a l n r n f p u l a t o r s is t y p i c a l l y c o n t r o l l e d so L ! C tasks are not done io 8 rfninum t i m e o p t i m~l manner. The r e s u l t is s u b s u n t f a l l y lower p r o d u c t i v i t y Chm Chat poteatial Ly possib le. JOCentLy a ColpUU C i O M l Ly e f f i c i e n t algorithm !ma been dereloped LO f i n d the t r u e iinimum tine optimal aocioa f o r a M n i p U b t O t novily along a s p e c i f i e d path in space rht uses bo-L!a f u l l aonlfnear dynamic c . k r a C t e t Of the a n i p u l a t r and the c o n s t r a i n t s Imposed by Lts i m p l o r e n u t f o n of c. 90 algorithm c a l l e d 0PYAR.Y is described which u n meat p r a c t i c a l l y gmeral six dogroe-of-freedom a u a i p u l a t o r s . Exraples a r e presented which show 3PTAR.Y eo ba a u s e f u l design tool f o r manipulators. their u r k s and work places. The algorftSm is extended L a O P T A X l LO i n c l u d e &e eoastraints fmposed by s a n i p u l a t o r payloads and end-effectors. A Computer Aided 3esi;o (CAD) C . fn troduc ti on The p r o d u c t i v i t y of p.ny i n d u s t r i a l robotic m n f p u l a c o c u s k s can 5. faproved by !mViBg n a n i p u l a t o r s aov. more quickLy. 3uc several f a c t o r s L h i t r u n i ? u l a t o r speeds. such as the f i i i t e c a p a b f l l t e s o f 3 s y s t e m ' s a c t u a t o r s and the level of jynamic forces a h i c h cSe object baing manipulated u a t o l e r a t e r i c h o u t lamage or b e i n s pulled out of che g r i p p e r . Ivan sore import.nc, the desisur o € currant a a n i p u l a t o r c o n t r o l l e t s do a o t p e r m i t i n d u s t r i a l n a n i p u l a t o r s to move as q u i c k l y as they 3f;hC. because t h y do not use e f f e c t i v e l y L.0 f u l l u p a b i l i t i e s of choir actuators, nor o p e r a t e a t o r aear che Units Lmposed by their payloads o r end-effectors. Yanipulator d p m f e s are h i z h l y i o n l i n e a r and complex. met? a c t u a f o r s a r e r r q u i r e d to produce complex, tine varying torques or f o r c e r in order f o r the a a n i p u l a t o r t o follow e v m r e l a t f v o l y simple paths: tSe dynamic f o r c e s a t the payload a r e e q u a l l y eo=?Lex. Today's commercfal manipulators are proqramed EO move along cheit p a t h s a t t h eonsunt a c c e i e r a t t o n s 3nd v e l o c i t i e s .

This paper presents a control methodology that enables nonlinear model-based control of pulse width modulated (PWM) pneumatic servo actuators. An averaging approach is developed to describe the equivalent continuous-time dynamics of a PWM controlled nonlinear system, which renders the system, originally discontinuous and possibly nonaffine in the input, into an equivalent system that is both continuous and affine in control input (i.e., transforms the system to nonlinear control canonical form). This approach is applied to a pneumatic actuator controlled by a pair of three-way solenoid actuated valves. The pneumatic actuation system is transformed into its averaged equivalent control canonical form, and a sliding mode controller is developed based on the resulting model. The controller is implemented on an experimental system, and the effectiveness of the proposed approach validated by experimental trajectory tracking.

Valve-controlled hydraulic actuation systems are favored in many applications due to their fast response, high power-to-weight ratio, and stability under variable working conditions. Efficiency, however, is the main disadvantage of these systems. Pump-controlled hydraulic actuations, on the other hand, eliminate energy losses in throttling valves and require less cooling. Furthermore, they inherently hold the ability to recover energy from assistive loads. Pump-controlled circuits for double-rod cylinders are well developed and are implemented in many industrial applications, including aviation. However, pump-controlled circuits for single-rod cylinders usually experience performance issues during specific modes of operation. In this paper, a new circuit using two valves to compensate for the differential flow of single-rod actuators is proposed. The compensating valves provide limited throttling over the differential flow only in critical operating regions to alleviate unwanted vel...

Improving the functional stability of shape memory alloys (SMAs), which undergo a reversible martensitic transformation, is critical for their applications and remains a central research theme driving advances in shape memory technology. By using a thin-film composition-spread technique and high-throughput characterization methods, the lattice parameters of quaternary Ti–Ni–Cu–Pd SMAs and the thermal hysteresis are tailored. Novel alloys with near-zero thermal hysteresis, as predicted by the geometric non-linear theory of martensite, are identified. The thin-film results are successfully transferred to bulk materials and near-zero thermal hysteresis is observed for the phase transformation in bulk alloys using the temperature-dependent alternating current potential drop method. A universal behavior of hysteresis versus the middle eigenvalue of the transformation stretch matrix is observed for different alloy systems. Furthermore, significantly improved functional stability, investigated by thermal cycling using differential scanning calorimetry, is found for the quaternary bulk alloy Ti50.2Ni34.4Cu12.3Pd3.1.

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Internet of Things(IoT) in recent days playing a vital role in networking related applications. However, there are several protocols available for building IoT applications, but RPL and CoAP are important protocols.There is a customized protocol requirement for specific IoT applications, while working on specific research problems. Further, adequate platforms are required to evaluate the performance of these protocols. These platforms need to be configured for the protocol, which is very crucial and timeconsuming task. At present, there is no collective and precise information available to carry out this work. This paper discusses two different open source platforms available for IoT. Also,various IoT research ideas need to design of IoT protocols. A few IoT communication technologies are mentioned in the paper. The detail analysis of, two common protocols, namely Routing Protocol for Low-Power Lossy Networks (RPL) and Constrained Application layer protocol (CoAP) is carried out with respect to latency delay and packet delivery ratio. The results, discussion and conclusion presented in this paper are useful for researchers, who are interested to work with IoT protocols and standards.

Due to pursuance along expand within measure accidents the death sum is increasing but it is a main subject than absolute can’t imaging. The rationale for street accidents are the driver’s potation consumption. The death dimension excellent according to bust and pressure is in excessive amongst rate splendid of conformity over such especially among nations as like India. So a dictation is proposed in conformity with become aware of the alcohol content fabric board atop the driver. The proposed job explores the possibility in conformity with discover wine at without a doubt previous utilizes concerning technology. The leader can't start the vehicle circumstance the potation content material cloth is upstairs the outset value. The delivered purposes in imitation about that regulation is the alcohol sensors trip solely the individual insertion within the driver’s foundation afterward desire no longer soak up into estimate touching the equalize passenger. It is additionally lower back in imitation including music the rebate regarding the automobile postulate into so much location the use on the mum or dad mark attention technique. This is done with the aid about measures of the sensors related in imitation of the Node MCU Arduino micro khan the region so much is programmed in consequence along assign a buzzer answer consequently the leader is below the affect concerning wine yet switch among pursuance along the vehicle.

The aim of this experimental study is the implementation of a practical and efficient closed-loop feedback control of the turbulent flow over a NACA-4412 airfoil equipped with leading-edge zero-net-mass-flux actuators. By using prior computation of correlations between particle image velocimetry data and multiple surface pressure measurements, real-time instantaneous low-dimensional estimates of the velocity field over the wing are then computed from the unsteady surface pressure. From such estimates, a direct knowledge of the state of the flow above the airfoil is obtained (i.e., attached, incipient separation, or fully separated flow). We first show the effectiveness of the low-dimensional modeling approach in extracting and estimating the underlying large-scale structures in a turbulent flow, using the proper orthogonal decomposition and the modified linear/quadratic stochastic measurements. We then show how such an approach is used successfully in a simple, but practical, proportional feedback loop to delay the separation of the flow over the wing at high angles of attack. The benefits of closed-loop vs open-loop control are then discussed. These fundamental results validate the use of low-dimensional modeling techniques for further, more sophisticated, closed-loop feedback control algorithms.

In this paper, modern civil aircraft electrical actuators are modeled, analyzed and controlled using Fuzzy Logic Control (FLC). The aircraft actuators aremodeled in PSIM and the obtained results verify that FLC is superior compared to classic controls. The FLC generates the required gate signals which drive the DC motor to follow the reference angle of the EMA actuator surface position.The aircraft system is analyzed with different number of actuators (5 kW each). In the meantime, the voltages and frequency of the main generator and the voltage of the actuator DC bus are kept within standard limits.

Electrically conductive materials capable of bending and stretching are useful for a wide range of applications such as smart clothing, flexible displays, stretchable circuits, strain gauges, implants , high-deformation microelectromechanical systems (MEMS), and dielectric elastomer actuators (DEAs), to name a few. The necessary strain varies from minimal (< 5 %) for applications such as retinal prostheses that only require conformal contact to a surface to high (> 60 %) for large-strain DEAs.

Smart Materials are also known as advanced materials or intelligent materials or responsive materials. These materials can be defined as advanced materials that can respond smartly to environmental changes. The general feature of all smart materials is the fact that one or more properties might be significantly altered under controlled conditions by external stimuli such as stress, moisture, electric fields, magnetic fields, light, temperature etc.. This study focuses on Smart Materials types and applications in various fields.

Supervisory Control and Data Acquisition (SCADA) systems are traditionally proprietary and well protected. Due to increasing use of commercial/open source technology and communication protocols, there are growing concerns about the associated security threats. SCADA networks are usually employed in critical infrastructure, therefore, not much technical data of the actual systems is accessible to the research community.

The present work concentrate on the study of the components of the excavator in
order to identify the problems faced while performing the lifting and digging operations and
to provide a design solution by using CAD-CAE systems.For light duty construction work,
generally mini hydraulic backhoe excavators are used and mostly there are soil surfaces for
excavation. So, design of backhoe excavator is critical task in context of digging force
developed through actuators during the digging operation. The important criteria for the
design to be safe is that, the digging forces developed by actuators must be greater than that of the resistive forces offered by the surface to be excavated. The two important factors considered during designing an excavator arm are productivity and fuel consumption. As the present mechanism used in excavator arm is subjected to torsional and bending stresses during lifting and digging operation respectively, because of which failure occurs frequently at the bucket end of the arm. So, the new mechanism of excavator arm is designed and the Pro-e software is used for making the 3D model of the excavator arm linkage. By using ANSYS workbench software static analysis of each of the excavator arm component is done at existing digging force and also at newly calculated digging force. Also the bucket volume is increased to compensate for the loss in production due to the reduction in digging force.

A state-feedback controller was designed to simulate the Starling response of the heart in a mock circulatory system (MCS). The controller drives a voice coil actuator (VCA) to follow a reference volume, and thus generate the desired chamber pressure, by using position and speed feedbacks. The reference volume was adjusted according to the maximum ventricular elastance (Emax), end-systolic ventricular pressure, and left atrial pressure to respond to load variation in the MCS. The controller was tested in computer simulation by changing the load conditions and Emax of the MCS. The MCS along with the controller was able to reproduce human heart function from healthy to sick conditions. A rotary ventricular assist device (VAD) was then introduced in the simulation to test the MCS. The MCS was able to produce a consistent cardiac function even with the presence of the VAD. These results suggest that the new MCS control system is able to simulate the cardiac function for VAD test.

This paper proposed an Engineering Implementation scheme on fault diagnosis for a real quadrotor Unmanned Aerial Vehicle (UAV) with actuators fault. A novel nonlinear observer is utilized to estimate the state of the system and to generate fault offset residuals for fault diagnosis. An Fault Diagnosis(FD) rules based on residuals is designed to isolate and estimate fault. Unlike former research work in FD for quadtrotors, the proposed FD is based on real flying data but not model simulation data and still have an acceptable FD accuracy. Experiments for the rotor fault have been carried out to show the performance and effectiveness of the proposed observer method and the results are discussed.

This paper analyzes the performances of an embedded closed-loop control system with a compensated magnetostrictive actuator (e.g., a Terfenol-D based device) for micropositioning tasks. The control system and the compensation algorithm are implemented, as a standalone application, on a microcontroller. The embedded application and its performance in terms of tracking error reduction is evaluated with respect to both open and closed loop configurations. The uncompensated case is used as a reference.

A wearable robot with linear actuators is required to maintain over the desired payload over whole range of knee joint angle even when the user is walking, sitting down/standing up while holding up weights. However, in knee-flexion posture, the lifting payload at the knee joint decreases drastically by the moment arm of linear actuators and the cosine of joint angle. In order to solve the problem of the payload decrease, the sub-links attaching on actuators and the sub-link with shank bending method are proposed. As the result, two methods are successfully proved to increase the payload by simulation.

Pump-controlled hydraulic circuits offer an energy-efficient solution for many applications. They combine the high power to weight ratio of hydraulic technology with the ease of control of electric technology. Pump-controlled circuits for double-rod cylinders are well developed as compared to those of single-rod cylinders. In spite of many initiatives, certain common pump-controlled single-rod cylinder solutions present stability issues during specific modes of operation. Common examples of the solutions are circuits that utilize pilot-operated check valves and circuits that use shuttle valves. In these circuits, velocity oscillations have been reported during actuator retraction at low assistive loads. In this paper, we study the area on the load-velocity graph of the available circuits where oscillatory behavior is experienced. We then propose a solution that shifts this critical zone towards lower loading values. This in turn reduces system response oscillations. Shifting the cri...

Bio-inspired hand-like gripper systems based on shape memory alloy (SMA) wire actuation have the potential to enable a number of useful applications in, e.g., the biomedical field or industrial assembly systems. The inherent high energy density makes SMA solutions a natural choice for systems with lightweight, low noise and high force requirements, such as hand prostheses or robotic systems in a human/machine environment. The focus of this research is the development, design and realization of a SMA-actuated prosthetic hand prototype with three fingers. The use of thin wires (100 µm diameter) allows for high cooling rates and therefore fast movement of each finger. Grouping several small wires mechanically in parallel allows for high force actuation. To save space and to allow for a direct transmission of the motion to each finger, the SMA wires are attached directly within each finger, across each phalanx. In this way, the contraction of the wires will allow the movement of the fingers without the use of any additional gears. Within each finger, two different bundles of wires are mounted: protagonist ones that create bending movement and the antagonist ones that enable stretching of each phalanx. The resistance change in the SMA wires is measured during actuation, which allows for monitoring of the wire stroke and potentially the gripping force without the use of additional sensors. The hand is built with modern 3D-printing technologies and its performance while grasping objects of different size and shape is experimentally investigated illustrating the usefulness of the actuator concept.

Microelectromechanical (MEM) Accelerometers measure the accelerations or vibrations experienced by objects due to inertial forces or mechanical excitations. To improve their proof mass displacement, several alternatives have been used, such as the design of different shapes of suspension beams. In this work, a new shape of beam is proposed based on alternated segments of different widths. To analyze its performance, one-quarter, middle and complete accelerometers were calculated and simulated; the results were compared with similar cases using conventional uniform-shaped beams. A notable improvement in the proof mass displacement was obtained in all cases, especially with the proposed symmetrical-shaped beam. Harmonic response and explicit dynamic analysis were also considered to discover performance when they are subjected to structural load. An improvement in amplitude displacement was also observed, as well as operation frequency reduction. From the explicit dynamic analysis, a f...

This paper describes a prototype and analytical studies of a spherical rolling robot, a new design of an omnidirectional robot system. The robot can arbitrarily begin to move in any direction to the target, and autonomously roll and reach any desired position. Our design has considered a spherical robot with an internal mechanism for propulsion. The propulsion mechanism will distribute weights radially along spokes fixed inside the sphere and enables the robot to accelerate, decelerate, and move with constant velocity. A mathematical model of the robot's dynamic and motion was instructed. An algorithmic motion planning is developed and, partly, pseudocode of that is presented. For a number of missions, it is shown experimentally that the model agrees well with the results.

Robust and early detection of oscillatory failures in the electrical flight control system of an aircraft is a crucial issue. Oscillatory failures, if not detected and passivated in time, can lead to strong interactions with loads and aeroelasticity and may potentially lead to structural damages. A nonlinear observer-based solution to detect such failures with small amplitude at a very early stage is presented. The stability and convergence proofs are given and experimental results with real A380 flight data are presented.

In Part I of this paper, we presented the fundamentals of the theory of IDA-PBC. In this part, we discuss the main new results and the practical applications of this control design approach as well as the current open problems and future directions.

The hyper-automaton is introduced as a model of complex control algorithms. The model reflects basic aspects of control algorithms: presence of an external environment, cyclic and event-driven functioning, synchronism, hierarchical structure and logical parallelism. The paper introduces basic definitions and conceptual means of hyper-automaton model, which encourage program implementation of the algorithms. A new kind of functional polymorphism we name event- driven polymorphism is distinguished and discussed.

ABSTRACT Application of a fuzzy logic controller to a class of hydraulically actuated industrial robots is investigated. A simple set of membership functions and rules are described which meets certain control requirements. An off-line routine based on the simplex method is outlined to tune the controller gains for an optimum response. The fuzzy control gains are tuned by minimizing the summation of absolute position errors over step input responses. The fuzzy logic controller is first examined through simulation of a two-link hydraulic robot of the same hydraulic configuration as many industrial manipulators. The controller has positive aspects which cannot be easily achieved by conventional control techniques. These include a fast rise-time and a well maintained damped response. The fuzzy controller is applied to an instrumented Unimate MK-II industrial hydraulic robot. The experimental results are encouraging in that the best performing control gains are found for different links with a reasonable number of trials and produce step responses with fast response and few oscillations at the set point. The controller demonstrates robustness

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This paper presents a concrete way of linking the JADE multi-agent system with the equipment (eg PLC, DCS, SCADA, HMI) comprised into a distributed industrial control system based on agents, using OPC servers. The differences between traditional control and agent based control approach also briefly showed. Industrial applications of multi-agent technology are limited, among others, especially due to the difficulties of communication between agents development environments and heterogeneous set of control devices, sensors and actuators which can be found in an industrial process. The solution involved the use of OPC standard. By using an OPC client written in Java, the connection between JADE multi-agent system development also written in Java, and OPC servers, was made; that allow access from JADE agent to process variables. The concrete steps for developing a JADE agent with the ability to connect it to the OPC server were presented. The content of this paper refers to a part of a dedicated application for monitoring, collection and archiving data of a manufacturing process in the automotive industry. The data are used by the maintenance planning system for carrying out checks and repairs on monitored equipment and machinery according to real functioning duration.

The application of conducting polymers for the direct conversion of electrical energy to mechanical energy in electromechanical actuators is analyzed using theoretical and experimental results. Basic principles of operation, predicted performance advantages and disadvantages, comparisons with natural muscle, evaluations of initial device demonstrations, and methods for improving device performance are provided. The very high predicted work densities per cycle, force generation capabilities, and power densities provide major advantages compared with piezoelectric polymersas do the low operation voltages. These advantages are countered by cycle life and energy conversion efficiency limitations, as well as the need to use microelectrodes in order to achieve very high rates. Hydrostatic devices and extensional devices that provide either in-phase or out-of-phase electrode deformations are considered. Special types of conducting polymer actuators are also proposed, including photo-powered, chemically powered and self-powered actuators, which provide novel methods for assembling complex micros• tructures. Novel methods are described for actuator fabrication, such as 'redox poling', wherein anode, cathode and separating electrolyte layers are generated from a film in a single redox step. New actuator compositions are also proposed for obtaining improved performance, such as conjugated carbon phases having conjugation in either two or three dimensions. Finally, conducting polymer actuators based on double-layer charging are proposed which are predicted to provide increased energy efficiency and cycle life compared with the faradaic actuators.

This paper addresses the problem of path generation and motion control for the autonomous maneuver of a farm vehicle with a trailed implement in headland. A reverse turn planner is firstly investigated, based on primitives connected together to easily generate the reference motion. Then, both steering and speed control algorithms are presented to accurately guide the vehicle-trailer system. They are based on a kinematic model extended with additional sliding parameters and on model predictive control approaches. Real world experiments have been carried out on a low friction terrain with an experimental mobile robot pulling a trailer. At the end of each row, the reverse turn is automatically generated to connect the next reference track, and the maneuver is autonomously performed by the vehicle-trailer system. Reported experiments demonstrate the capabilities of the proposed algorithms.

This paper defines and compares fault tolerances of a triple flight control architecture to a quadruple type, and investigates the impact of worst case failures on transient response of an aircraft. New insight in computing fault coverage is discussed. Two coverage models were used to compute the Probability of Loss of Control (PLOC) and the Probability of Mission Abort (PMA) for candidate architectures. Results indicate that both triple and quadruple architectures can meet the fault tolerant requirements with an acceptable level of transients upon first and second failures. Triple architectures will require a higher level of fault detection, isolation, and accommodation coverage than quadruple architectures and produce substantially larger transients upon second failure. REQUIREMENTS Derived from the MIL-F-9490D, a Flight Control System (FCS) (consisting of sensors, computers, and actuators) must be designed to a Probability of Mission Abort (PMA) of 5 x 10-5 and a Probability of Loss of Control (PLOC) of 5 X 10-7 per Flight Hour (FH). Top down apportionments of these requirements to Flight Control Computers (FCC) [ 11 are estimatedas: PMA = lO-5/FH, andPLOC = 5 x IO-VFH. MIL-STD 882B requires a FCS be capable of exhibiting a Fail-Operational / Fail-Operational (F02) S c a~~+ i o Once the aircraft is up and flying. Coverage for Fault Detection, Isolation, and Accommodation (FDIA), and the confidence intervals associated with these coverage parameters are not well defined.

Continuous-facesheet and segmented Boston Micromachines Corporations&#x27; (BMC) Micro-Electrical Mechanical Systems (MEMS) Deformable Mirrors (DM) have been tested for their response to high-power visible-wavelength laser light. The deformable mirrors, coated with either protected silver or bare aluminum, were subjected to a maximum of 2 Watt laser-light at a wavelength of 532 nanometers. The laser light was incident on a ~ 3.5×3.5 cm area for time periods from minutes to 7 continuous hours. Spot heating from the laser-light is measured to induce a local bulge in the surface of each DM. For the aluminum-coated continuous facesheet DM, the induced spot heating changes the surface figure by 16 nm rms. The silver-coated continuous-facesheet and segmented (spatial light modulator) DMs experience a 6 and 8 nm surface rms change in surface quality with the laser at 2 Watts. For spatial frequencies less than the actuator spacing (300 mm), the laser induced surface bulge is shown to be rem...

ABSTRACT Ultrasonically Assisted Machining (UAM) is an emerging technology that has proven to be very efficient in improving the surface finishing in material machining such as turning, milling, and drilling. Smart material actuators are used in such applications to vibrate the cutting tip while machining, hence, improving the manipulated surface. In order to achieve that, it is required to vibrate the cutting tip at certain frequency with certain amplitude. In fact, controlling the amplitude of these smart actuators is a tedious and difficult task due to the inherent nonlinearities associated with smart materials. In this paper, two control algorithms are proposed; sliding mode controller with high frequency (SMHF) and proportional-integral controller with RMS (PIRMS). Numerical simulations are presented to demonstrate the effectiveness of using the proposed controller. The PIRMS algorithm demonstrates a better performance when compared with the SMHF algorithm.

An experimental study is conducted to characterize the performance of a pulsed-plasma jet (called a "spark jet" by other researchers) for potential use in supersonic flow control applications. A pulsed-plasma jet is a high-speed synthetic jet that is generated by striking an electrical discharge in a small cavity. The gas in the cavity pressurizes owing to the heating and is allowed to escape through a small orifice. To obtain an estimate of the relative strength of the pulsed-plasma jet, the jet is injected normally into a Mach 3 crossflow and the penetration distance is measured by using schlieren imaging. These measurements show that the jet penetrates 1.5 boundary-layer thicknesses into the crossflow and the jet-to-crossflow momentum flux ratio is estimated to be 0.6. A series of experiments was conducted to determine the characteristics of the pulsed-plasma jet issuing into stagnant air at a pressure of 35 torr. These results show that typical jet velocities of about 250 m=s can be induced with discharge energies of about 30 mJ per jet. Furthermore, the maximum pulsing frequency was found to be about 5 kHz, because above this frequency the jet begins to misfire. The misfiring appears to be due to the finite time it takes for the cavity to be recharged with ambient air between discharge pulses. The velocity at the exit of the jet is found to be primarily dependent on the discharge current and independent of other discharge parameters such as cavity volume and orifice diameter. Temperature measurements are made using optical emission spectroscopy and reveal the presence of considerable nonequilibrium between rotational and vibrational modes. The gas heating efficiency was found to be 10% and this parameter is shown to have a direct effect on the plasma jet velocity. These results indicate that the pulsed-plasma jet creates a sufficiently strong flow perturbation that holds great promise as a supersonic flow actuator. Nomenclature j = density of the pulsed-plasma jet 1 = freestream density u j = exit velocity of the pulsed-plasma jet u 1 = freestream velocity

The paper deals with low-level fieldbus interconnections intended for use in simple digital measurement and control applications employing ASI (Actuator-Sensor-Interface), which specifies an industrial communication connection between the foremost binary sensors and actuators and a controlling site. The kernel of the paper stems from two case studies that offer a more detailed insight into system design employing ASI interconnections. The first case deals with a regular implementation of the gateway between ASI and NBIP (nine-bit inter-processor protocol), which exemplifies a microcontroller-dedicated protocol, whereas the second case introduces an ASI-ASI coupler enabling the realization of hierarchical ASI systems.