A 19 Element Hexagonal Actuator Arrangement Continuous Face-Sheet MEMS Deformable Mirror

2012 ◽  
Vol 503 ◽  
pp. 169-173
Author(s):  
Wei Min Wang ◽  
Feng Gang Tao ◽  
Jian Fei Zhang ◽  
Jun Yao
Keyword(s):  
High Speed ◽  
Fill Factor ◽  
Fast Response ◽  
Face Sheet ◽  
Deformable Mirror ◽  
Test Results ◽  
Wavefront Control ◽  
Small Aperture ◽  
New Device ◽  
Fast Dynamic

A new hexagonal actuator arrangement continuous face-sheet MEMS deformable mirror is proposed, a mirror array with 19 elements is fabricated by a surface micromachining process. This design has a good fitting capability and a fast dynamic response. The fabricated sample is tested by an optical profiler. Simulation and test results indicate that it has a small aperture size, a high fill factor, a fast response time and a high working bandwidth. This new device provides a possibility of manufacturing a large-actuator-count DM for high speed wavefront control.

An Actively Controlled Hydraulic Carbody Centering System for the Lateral Suspensions of High Speed Trains

2009 ◽  
Author(s):  
Giovanni Jacazio ◽  
Alberto Magnani ◽  
Laura Gastaldi ◽  
Gualtiero Balossini
Keyword(s):  
High Speed ◽  
Fast Response ◽  
Control Law ◽  
System Control ◽  
Test Results ◽  
Damped Oscillations ◽  
Innovative Solution ◽  
High Speed Trains ◽  
And Performance ◽  
Actuation Systems

High speed trains normally use pneumatic actuation systems to recenter the carbody with respect to the bogie when the train negotiates a curve. Pneumatic systems are used because of their compliance, necessary to ensure dynamic isolation between carbody and bogie, but have the drawbacks of large dimensions and slow response, often accompanied by a few damped oscillations. An innovative solution was developed using hydraulic actuators with an adaptive control law providing the actuators with artificial compliance, hence making them suitable for this application. A carbody centering system is thus obtained presenting fast response, small volume and the necessary compliance. The optimal control law for this system was defined, the system dynamic characteristics were analyzed and a technological demonstrator was built to assess the system merits. The paper presents the theoretical grounds for the system control, its implementation and performance, and the most significant test results obtained with the technological demonstrator.

Direct Current Deadbeat Predictive Controller for BLDC Motor Using Single DC-Link Current Sensor

2020 ◽  
Vol 38 (8A) ◽  
pp. 1187-1199
Author(s):  
Qaed M. Ali ◽  
Mohammed M. Ezzalden
Keyword(s):  
Control System ◽  
High Speed ◽  
Fast Response ◽  
Bldc Motor ◽  
Current Controller ◽  
Three Phase ◽  
Predictive Controller ◽  
Two Phases ◽  
Dc Current ◽  
Three Phase Inverter

BLDC motors are characterized by electronic commutation, which is performed by using an electric three-phase inverter. The direct control system of the BLDC motor consists of double loops; including the inner-loop for current regulating and outer-loop for speed control. The operation of the current controller requires feedback of motor currents; the conventional current controller uses two current sensors on the ac side of the inverter to measure the currents of two phases, while the third current would be accordingly calculated. These two sensors should have the same characteristics, to achieve balanced current measurements. It should be noted that the sensitivity of these sensors changes with time. In the case of one sensor fails, both of them must be replaced. To overcome this problem, it is preferable to use one sensor instead of two. The proposed control system is based on a deadbeat predictive controller, which is used to regulate the DC current of the BLDC motor. Such a controller can be considered as digital controller mode, which has fast response, high precision and can be easily implemented with microprocessor. The proposed control system has been simulated using Matlab software, and the system is tested at a different operating condition such as low speed and high speed.

scholarly journals 2D-3D integration of hexagonal boron nitride and a high-κ dielectric for ultrafast graphene-based electro-absorption modulators

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hitesh Agarwal ◽  
Bernat Terrés ◽  
Lorenzo Orsini ◽  
Alberto Montanaro ◽  
Vito Sorianello ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hafnium Oxide ◽  
High Speed ◽  
Hexagonal Boron Nitride ◽  
Temperature Stability ◽  
Cost Effective ◽  
Fold Increase ◽  
Building Blocks ◽  
High Quality ◽  
New Device

AbstractElectro-absorption (EA) waveguide-coupled modulators are essential building blocks for on-chip optical communications. Compared to state-of-the-art silicon (Si) devices, graphene-based EA modulators promise smaller footprints, larger temperature stability, cost-effective integration and high speeds. However, combining high speed and large modulation efficiencies in a single graphene-based device has remained elusive so far. In this work, we overcome this fundamental trade-off by demonstrating the 2D-3D dielectric integration in a high-quality encapsulated graphene device. We integrated hafnium oxide (HfO2) and two-dimensional hexagonal boron nitride (hBN) within the insulating section of a double-layer (DL) graphene EA modulator. This combination of materials allows for a high-quality modulator device with high performances: a ~39 GHz bandwidth (BW) with a three-fold increase in modulation efficiency compared to previously reported high-speed modulators. This 2D-3D dielectric integration paves the way to a plethora of electronic and opto-electronic devices with enhanced performance and stability, while expanding the freedom for new device designs.

Experimental Investigation During Stall and Surge in a Transonic Fan Stage and Rotor-Only Configuration

2006 ◽  
Author(s):  
A. J. Gannon ◽  
G. V. Hobson ◽  
R. P. Shreeve ◽  
I. J. Villescas
Keyword(s):  
High Speed ◽  
Fast Response ◽  
Pressure Measurements ◽  
Post Processing ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
The Difference ◽  
Data Signal ◽  
Transonic Fan ◽  
Casing Pressure

High-speed pressure measurements of a transonic compressor rotor-stator stage and rotor-only configuration during stall and surge are presented. Rotational speed data showed the difference between the rotor-only case and rotor-stator stage. The rotor-only case stalled and remained stalled until the control throttle was opened. In the rotor-stator stage the compressor surged entering a cyclical stalling and then un-stalling pattern. An array of pressure probes was mounted in the case wall over the rotor for both configurations of the machine. The fast response probes were sampled at 196 608 Hz as the rotor was driven into stall. Inspection of the raw data signal allowed the size and speed of the stall cell during its growth to be investigated. Post-processing of the simultaneous signals of the casing pressure showed the development of the stall cell from the point of inception and allowed the structure of the stall cell to be viewed.

Measurement and Analysis on Transient Thermal Characteristics of High Speed Motorized Spindle

2011 ◽  
Vol 52-54 ◽  
pp. 2021-2026
Author(s):  
Gui Ling Deng ◽  
Can Zhou
Keyword(s):  
High Speed ◽  
Thermal Deformation ◽  
Thermal Characteristics ◽  
Measuring System ◽  
Test Results ◽  
Motorized Spindle ◽  
Measurement And Analysis ◽  
Turning Center ◽  
Transient Thermal ◽  
Deformation Compensation

Thermal deformation is an important factor to affect the accuracy of the motorized spindle, the core component of high-speed machine tool. To understand the spindle system transient thermal characteristics of the high-speed turning center CH7516GS, some high-precision sensors and high-frequency data acquisition system is used to establish the temperature and displacement measuring system. The thermal deformation compensation model is established on the basis of the experimental test results.

A 25 Gbps VCSEL driving ASIC: an attempt for ultra-high-speed front-end readout applications

2022 ◽  
Vol 17 (01) ◽  
pp. C01040
Author(s):  
C. Zhao ◽  
D. Guo ◽  
Q. Chen ◽  
N. Fang ◽  
Y. Gan ◽  
...  
Keyword(s):  
High Speed ◽  
Cmos Technology ◽  
Test Results ◽  
Eye Diagram ◽  
Optical Links ◽  
Optical Module ◽  
Active Feedback ◽  
High Bandwidth ◽  
Output Driver ◽  
Very High

Abstract This paper presents the design and the test results of a 25 Gbps VCSEL driving ASIC fabricated in a 55 nm CMOS technology as an attempt for the future very high-speed optical links. The VCSEL driving ASIC is composed of an input equalizer stage, a pre-driver stage and a novel output driver stage. To achieve high bandwidth, the pre-driver stage combines the inductor-shared peaking structure and the active-feedback technique. A novel output driver stage uses the pseudo differential CML driver structure and the adjustable FFE pre-emphasis technique to improve the bandwidth. This VCSEL driver has been integrated in a customized optical module with a VCSEL array. Both the electrical function and optical performance have been fully evaluated. The output optical eye diagram has passed the eye mask test at the data rate of 25 Gbps. The peak-to-peak jitter of 25 Gbps optical eye is 19.5 ps and the RMS jitter is 2.9 ps.

Stall Inception in a High Speed Centrifugal Compressor During Speed Transients

2017 ◽  
Author(s):  
Fangyuan Lou ◽  
John C. Fabian ◽  
Nicole L. Key
Keyword(s):  
Heat Transfer ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Flow Instability ◽  
Leading Edge ◽  
Fast Response ◽  
Rotating Stall ◽  
Transient Performance ◽  
Stall Inception ◽  
Pressure Transducers

The inception and evolution of rotating stall in a high-speed centrifugal compressor are characterized during speed transients. Experiments were performed in the Single Stage Centrifugal Compressor (SSCC) facility at Purdue University and include speed transients from sub-idle to full speed at different throttle settings while collecting transient performance data. Results show a substantial difference in the compressor transient performance for accelerations versus decelerations. This difference is associated with the heat transfer between the flow and the hardware. The heat transfer from the hardware to the flow during the decelerations locates the compressor operating condition closer to the surge line and results in a significant reduction in surge margin during decelerations. Additionally, data were acquired from fast-response pressure transducers along the impeller shroud, in the vaneless space, and along the diffuser passages. Two different patterns of flow instabilities, including mild surge and short-length-scale rotating stall, are observed during the decelerations. The instability starts with a small pressure perturbation at the impeller leading edge and quickly develops into a single-lobe rotating stall burst. The stall cell propagates in the direction opposite of impeller rotation at approximately one third of the rotor speed. The rotating stall bursts are observed in both the impeller and diffuser, with the largest magnitudes near the diffuser throat. Furthermore, the flow instability develops into a continuous high frequency stall and remains in the fully developed stall condition.

A New Device for High-Speed Biaxial Tissue Testing: Application to Traumatic Rupture of the Aorta

2005 ◽  
Author(s):  
Matthew J. Mason ◽  
Chirag S. Shah ◽  
Muralikrishna Maddali ◽  
King H. Yang ◽  
Warren N. Hardy ◽  
...  
Keyword(s):  
High Speed ◽  
Traumatic Rupture ◽  
New Device

Experimental Test Results for Four High-Speed, High-Pressure, Orifice-Compensated Hybrid Bearings

1994 ◽  
Vol 116 (1) ◽  
pp. 147-153 ◽  
Author(s):  
N. M. Franchek ◽  
D. W. Childs
Keyword(s):  
High Speed ◽  
Load Capacity ◽  
Pressure Ratio ◽  
Reynolds Numbers ◽  
Orifice Diameter ◽  
Test Results ◽  
Rotordynamic Coefficients ◽  
Geometric Configurations ◽  
Overall Performance ◽  
Mass Terms

In this study, four hybrid bearings having different geometric configurations were experimentally tested for their static and dynamic characteristics, including flowrate, load capacity, rotordynamic coefficients, and whirl frequency ratio. The four bearings included a square-recess, smooth-land, radial-orifice bearing (baseline), a circular-recess bearing, a triangular-recess bearing, and an angled-orifice bearing. Each bearing had the same orifice diameter rather than the same pressure ratio. Unique to these test results is the measurement of the added mass terms, which became significant in the present tests because of high operating Reynolds numbers. Comparisons of the results were made between bearings to determine which bearing had the best performance. Based on the parameters of interest, the angled-orifice bearing has the most favorable overall performance.

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