MEMS-based, phase-shifting interferometer

Provided herein are optical devices fabricated to include a reflective surface, actuators and stress-relieving structures. Systems containing such devices, and methods of manufacturing such devices, are also provided

H∞-based Position Control of a 2DOF Piezocantilever Using Magnetic Sensors.

International audienceThe article addresses the position control problem of a 2 degrees of freedom (DOF) piezoelectric cantilever by means of an embedded magnetic-based position sensor. The active part of the piezocantilever used in the experimental setup is similar to cantilevers previously developed and already used for low-frequency micro-actuators in microrobotics devices. The contribution relies on the estimation of the biaxial displacement of the piezocantilever via conventional Hall-effect (HE) sensors, reducing the mechanical complexity and cost aspects.The actual sensing approach is validated via the implementation of a real-time position control based on the H1 scheme. In comparison with high resolution sensors, as laser or confocal chromatic (high-cost) or capacitive displacement (bulky), the actual sensor-control system is provides a satisfactory performance to cope with traditional micro-positioning tasks requiring a micrometer resolution. The performanceof the embedded magnetic-based position sensor is evaluated, in open- and closed-loop, with respect the measurements provided by a Keyence laser sensors

PKM mechatronic clamping adaptive device

This study proposes a novel adaptive fixturing device based on active clamping systems for smart micropositioning of thin-walled precision parts. The modular architecture and the structure flexibility make the system suitable for various industrial applications. The proposed device is realized as a Parallel Kinematic Machine (PKM), opportunely sensorized and controlled, able to perform automatic error-free workpiece clamping procedures, drastically reducing the overall fixturing set-up time. The paper describes the kinematics and dynamics of this mechatronic system. A first campaign of experimental trails has been carried out on the prototype, obtaining promising results

A Study of dynamic force measurement based on the levitation mass method

In this thesis, methods based on the levitation mass method (LMM) for evaluating the frictional characteristics of a linear ball bearing, the electro-mechanical characteristics of a voice coil and a piezo-electric actuator and for removing the velocity limitation of laser Doppler interferometer (LDI) are proposed. In the LMM, the inertial force of a levitated mass used as the reference force for measuring dynamic force is measured as the product of the mass and acceleration. For evaluating the dynamical friction of linear ball bearing, two corner-cube prisms (CC) are attached to a moving part which is connected to the ball bearing. The acceleration of the gravity center of the moving part is estimated from the accelerations of the two CCs which are measured using a dual axis LDI. The frictional force is measured as the product of the mass of the moving part and the acceleration of the gravity center. For evaluating the voice coil actuator, a moving part levitated using an aerostatic linear bearing is connected to the coil. The dynamic force generated by the coil is measured as the inertial force of the moving part. The velocity of the moving part is measured using a LDI. Other mechanical characteristics such as position, acceleration and force are calculated from the measured velocity. With the electrical characteristics mea-sured using a digital voltmeter, the relationships between electrical and mechanical characteristics are evaluated. For measuring the electro-mechanical characteristics of piezo-electric actuator, a CC considered as an inertial mass is attached to the top of the actuator instead of the moving part. The dynamic force generated by the actuator is measured as the inertial force of CC. Based on this method, the force-displacement behavior of the actuator under dynamic condition is evaluated. The relationship of energy conversion between electrical and mechanical domains is also evaluated based on the observed results. In the LMM, the velocity of moving part is measured using a LDI whose laser source is a Zeeman-type two-frequency laser. However, the measurable velocity of LDI is limited by the frequency di.erence of laser in back and forth motion. In order to get high measurable velocity in back and forth motion, a dual beat-frequencies laser Doppler interferometer (DB-LDI) is developed and applied. In DB-LDI, two laser beams with di.erence frequency (f1,f2) are divided into reference beams and signal beams by a non-polarized beams splitter. They are used to produce two beat signals. When the object moving, the beat frequencies of beat signals are detected as |f ′ . f2| and |f ′ . f1|, respectively. For back and forth motion, although the 12 velocity of the object calculated from one beat frequency reaches critical velocity, the velocity calculated from the other one is far from critical velocity. The DB-LDI has been applied to realize a high-speed impact testing. During the collision, the velocity of the mass, even higher than the critical velocity, is accurately measured using the DB-LDI.学位記番号：工博甲47

Design Considerations and Thermodynamic Feasibility Study of a Meso-scale Refrigerator

Recent advances in micro-fabrication technology have ushered a new era in miniaturization of chemical, environmental and energy systems. This foreseeable trend towards miniaturization in chemical, environmental and mechanical systems is expected to revolutionize the ways the human life is being perceived today. The high volume and mass reproducibility is seen as the striking aspect of micro-fabrication based miniature systems, offering economies far exceeding than the economies of scale obtained in large plants. The focus of this thesis work is directed at the thermodynamic feasibility and preliminary prototype design for a meso-scale refrigerator. Miniaturization to sub-centimeter domain will enable configuring these refrigerator units as sheet architectures integrated in layers, facilitating efficient local control of temperature. In the design abstraction, the entire refrigeration unit, comprising motor-compressor, evaporator, condenser, valves and fluidic control, is to be fabricated from several layers of bonded silicon wafers. The material treated in this thesis provides a perspective on the actuation mechanism of the integrated rotor-compressor through an axial-drive high-throughput variable capacitance electrostatic disk motor and underlying stator assembly. The design optimization of the motor actuation dynamics to extract optimal set of design parameters is provided to yield reasonably good output power of the compressor

Controllability and Observability of 2 DOF Permanent Magnet Maglev System with Linear Control

Abstract: A new type of 2 DOF (degree of freedom) magnetic levitation system for multi-DOF levitation is proposed. In this system, the force of permanent magnets are used for levitation and controlled by adjusting the reluctance of the magnetic circuit. Using permanent magnets, the feature of this system is effective for saving energy and avoiding heat generation. First, the principle of the levitation system and typical reluctance control methods are described. Second, an experimental device based on the principle is introduced. finally, the feasibility of this system is considered from linear control theory

A Characterization of Actuation Techniques for Generating Movement in Shape-Changing Interfaces

Abstract This article characterizes actuation techniques for generating movement in shape-changing displays with physically reconfigurable geometry. To date, few works in Human Computer Interaction literature provide detailed and reflective descriptions of the implementation techniques used in shape-changing displays. This hinders the rapid development of novel interactions as researchers must initially spend time understanding technologies before prototyping new interactions and applications. To bridge this knowledge gap, we propose a taxonomy that classifies actuator characteristics and simplifies the process for designers to select appropriate technologies that match their requirements for developing shape-displays. We scope our investigation to linear actuators that are used in grid configurations. The taxonomy is validated by (a) examining current implementation techniques of motorized, pneumatic, hydraulic, magnetic, and shape-memory actuators in the literature, (b) constructing prototypes to address limited technical details and explore actuator capabilities in depth, (c) describing a use-case scenario through a case study that details the construction of a 10 ? 10 actuator shape-display, and (d) a set of guidelines to aid researchers in selecting actuation techniques for shape-changing applications. The significance of our taxonomy is twofold. First, we provide an original contribution that enables HCI researchers to appropriately select actuation techniques and build shape-changing applications. This is situated amongst other past works that have investigated broader application scenarios such as a shape-changing vocabulary, a framework for shape transformations, material properties, and technical characteristics of various actuators. Second, we carry out in-depth investigations to validate our taxonomy and expand the knowledge of vertical actuation in shape-changing applications to enable rapid development