Injection locking of optomechanical oscillators via acoustic waves

Injection locking is a powerful technique for synchronization of oscillator networks and controlling the phase and frequency of individual oscillators using similar or other types of oscillators. Here, we present the first demonstration of injection locking of a radiation-pressure driven optomechanical oscillator (OMO) via acoustic waves. As opposed to previously reported techniques (based on pump modulation or direct application of a modulated electrostatic force), injection locking of OMO via acoustic waves does not require optical power modulation or physical contact with the OMO and it can easily be implemented on various platforms. Using this approach we have locked the phase and frequency of two distinct modes of a microtoroidal silica OMO to a piezoelectric transducer (PZT). We have characterized the behavior of the injection locked OMO with three acoustic excitation configurations and showed that even without proper acoustic impedance matching the OMO can be locked to the PZT and tuned over 17 kHz with only -30 dBm of RF power fed to the PZT. The high efficiency, simplicity and scalability of the proposed approach paves the road toward a new class of photonic systems that rely on synchronization of several OMOs to a single or multiple RF oscillators with applications in optical communication, metrology and sensing. Beyond its practical applications, injection locking via acoustic waves can be used in fundamental studies in quantum optomechanics where thermal and optical isolation of the OMO are critical

Electronic/electric technology benefits study

The benefits and payoffs of advanced electronic/electric technologies were investigated for three types of aircraft. The technologies, evaluated in each of the three airplanes, included advanced flight controls, advanced secondary power, advanced avionic complements, new cockpit displays, and advanced air traffic control techniques. For the advanced flight controls, the near term considered relaxed static stability (RSS) with mechanical backup. The far term considered an advanced fly by wire system for a longitudinally unstable airplane. In the case of the secondary power systems, trades were made in two steps: in the near term, engine bleed was eliminated; in the far term bleed air, air plus hydraulics were eliminated. Using three commercial aircraft, in the 150, 350, and 700 passenger range, the technology value and pay-offs were quantified, with emphasis on the fiscal benefits. Weight reductions deriving from fuel saving and other system improvements were identified and the weight savings were cycled for their impact on TOGW (takeoff gross weight) and upon the performance of the airframes/engines. Maintenance, reliability, and logistic support were the other criteria

磁性流体を用いたバックドライブ可能な油圧アクチュエータの開発

早大学位記番号:新7478早稲田大

Extended analytical charge modeling for permanent-magnet based devices : practical application to the interactions in a vibration isolation system

This thesis researches the analytical surface charge modeling technique which provides a fast, mesh-free and accurate description of complex unbound electromagnetic problems. To date, it has scarcely been used to design passive and active permanent-magnet devices, since ready-to-use equations were still limited to a few domain areas. Although publications available in the literature have demonstrated the surface-charge modeling potential, they have only scratched the surface of its application domain. The research that is presented in this thesis proposes ready-to-use novel analytical equations for force, stiffness and torque. The analytical force equations for cuboidal permanent magnets are now applicable to any magnetization vector combination and any relative position. Symbolically derived stiffness equations directly provide the analytical 3 £ 3 stiffness matrix solution. Furthermore, analytical torque equations are introduced that allow for an arbitrary reference point, hence a direct torque calculation on any assembly of cuboidal permanent magnets. Some topics, such as the analytical calculation of the force and torque for rotated magnets and extensions to the field description of unconventionally shaped magnets, are outside the scope of this thesis are recommended for further research. A worldwide first permanent-magnet-based, high-force and low-stiffness vibration isolation system has been researched and developed using this advanced modeling technique. This one-of-a-kind 6-DoF vibration isolation system consumes a minimal amount of energy (Ç 1W) and exploits its electromagnetic nature by maximizing the isolation bandwidth (> 700Hz). The resulting system has its resonance > 1Hz with a -2dB per decade acceleration slope. It behaves near-linear throughout its entire 6-DoF working range, which allows for uncomplicated control structures. Its position accuracy is around 4mum, which is in close proximity to the sensor’s theoretical noise level of 1mum. The extensively researched passive (no energy consumption) permanent-magnet based gravity compensator forms the magnetic heart of this vibration isolation system. It combines a 7.1kN vertical force with <10kN/m stiffness in all six degrees of freedom. These contradictory requirements are extremely challenging and require the extensive research into gravity compensator topologies that is presented in this thesis. The resulting cross-shaped topology with vertical airgaps has been filed as a European patent. Experiments have illustrated the influence of the ambient temperature on the magnetic behavior, 1.7h/K or 12N/K, respectively. The gravity compensator has two integrated voice coil actuators that are designed to exhibit a high force and low power consumption (a steepness of 625N2/W and a force constant of 31N/A) within the given current and voltage constraints. Three of these vibration isolators, each with a passive 6-DoF gravity compensator and integrated 2-DoF actuation, are able to stabilize the six degrees of freedom. The experimental results demonstrate the feasibility of passive magnet-based gravity compensation for an advanced, high-force vibration isolation system. Its modular topology enables an easy force and stiffness scaling. Overall, the research presented in this thesis shows the high potential of this new class of electromagnetic devices for vibration isolation purposes or other applications that are demanding in terms of force, stiffness and energy consumption. As for any new class of devices, there are still some topics that require further study before this design can be implemented in the next generation of vibration isolation systems. Examples of these topics are the tunability of the gravity compensator’s force and a reduction of magnetic flux leakage

Emerging Multiport Electrical Machines and Systems: Past Developments, Current Challenges, and Future Prospects

Distinct from the conventional machines with only one electrical and one mechanical port, electrical machines featuring multiple electrical/mechanical ports (the so-called multiport electrical machines) provide a compact, flexible, and highly efficient manner to convert and/or transfer energies among different ports. This paper attempts to make a comprehensive overview of the existing multiport topologies, from fundamental characteristics to advanced modeling, analysis, and control, with particular emphasis on the extensively investigated brushless doubly fed machines for highly reliable wind turbines and power split devices for hybrid electric vehicles. A qualitative review approach is mainly adopted, but strong efforts are also made to quantitatively highlight the electromagnetic and control performance. Research challenges are identified, and future trends are discussed

Towards Untethered Soft Robots Driven By Electrohydraulic Artificial Muscles

As humans, we are continually integrating technology into our everyday lives. From wearable smart watches to autonomous vacuum cleaners, modern day machines are steadily moving out of warehouses and factories and into our homes to enhance our lifestyles. In doing so, there is an ever-growing need for machines that can safely operate in extremely diverse or unpredictable environments, which often includes collaborative spaces near humans. This requirement presents challenges for traditional robots that commonly employ rigid architectures driven by heavy motors, gears, and linkages, which rely on precise computation of the state at each degree of freedom to safely function. Moreover, the underlying mechanics of these modern-day robotic architectures are fundamentally different than those which have evolved naturally; biological organisms exploit a host of compliant, robust, and multifunctional structures that tightly integrate actuation, sensing, and control. These biological structures, in animals for instance, enable feats of strength, agility, and autonomy that are currently impossible for human-made robots. A paradigm shift in robotic design and implementation is required for the next generation of machines. This approach will reinvent the idea of a robot, moving from a rigid block design to a soft continuum that integrates lightweight, compliant, and versatile components. While this approach will require multi-disciplinary advances in material science, control theory, and engineering, a fundamental component of these machines will ultimately be the actuators that drive them. Thus, researchers and engineers are developing soft actuators that mimic the strength, speed, and scalability of natural muscle. These bio-inspired components could unlock a multitude of applications for machines, and even blur the lines between science and science fiction. For example, soft wearable robots can provide haptic feedback for an immersive virtual reality experience, ultra-adaptable soft robotic cephalopods could explore marine environments to conduct research and reconnaissance, while highly resilient space robots could explore extraterrestrial environments to uncover the origins of life. This dissertation is focused on a novel type of soft actuator (or artificial muscle) called a Hydraulically Amplified Self-healing ELectrostatic (HASEL) actuator, and its application to soft robotics devices. The first chapter will explore the state-of-the-art in soft robotics technologies, with a focus on soft actuation. The second chapter will elucidate the fundamentals of HASEL actuators and their application to soft robotic technologies. The third chapter will detail a toolkit based on off-the-shelf-materials that can be used to prototype, fabricate, power, and test HASEL actuators. This chapter will detail exemplary designs of HASEL, their modes of actuation and performance, as well as their application to soft-robotic devices such as a continuum robot capable of grasping and manipulating delicate objects. Continuing to the fourth chapter, a novel design for a linearly contractile actuator is presented, characterized on both an experimental and theoretical basis, and then demonstrated as a soft tubular pump. In the fifth chapter, we develop a state-of-the-art 10-channel high voltage power supply to independently control groups of HASEL actuators. This power supply features a compact form-factor that is about the size of a standard smart phone. Next, chapter six will focus on soft robots for space exploration. A feasibility study details a robot design for asteroid mining, and initial prototypes are discussed with a focus on electrohydraulic actuation and electrostatic adhesion mechanisms for robot locomotion and grappling. Finally, chapter seven concludes the dissertation with a summary of the developments presented here, while also laying the framework for future studies.</p

Reduced-order modeling of power electronics components and systems

This dissertation addresses the seemingly inevitable compromise between modeling fidelity and simulation speed in power electronics. Higher-order effects are considered at the component and system levels. Order-reduction techniques are applied to provide insight into accurate, computationally efficient component-level (via reduced-order physics-based model) and system-level simulations (via multiresolution simulation). Proposed high-order models, verified with hardware measurements, are, in turn, used to verify the accuracy of final reduced-order models for both small- and large-signal excitations. At the component level, dynamic high-fidelity magnetic equivalent circuits are introduced for laminated and solid magnetic cores. Automated linear and nonlinear order-reduction techniques are introduced for linear magnetic systems, saturated systems, systems with relative motion, and multiple-winding systems, to extract the desired essential system dynamics. Finite-element models of magnetic components incorporating relative motion are set forth and then reduced. At the system level, a framework for multiresolution simulation of switching converters is developed. Multiresolution simulation provides an alternative method to analyze power converters by providing an appropriate amount of detail based on the time scale and phenomenon being considered. A detailed full-order converter model is built based upon high-order component models and accurate switching transitions. Efficient order-reduction techniques are used to extract several lower-order models for the desired resolution of the simulation. This simulation framework is extended to higher-order converters, converters with nonlinear elements, and closed-loop systems. The resulting rapid-to-integrate component models and flexible simulation frameworks could form the computational core of future virtual prototyping design and analysis environments for energy processing units