Pretension Analysis for Piezoelectric Stack Actuator in Nano-Positioning Stage

2017 ◽  
Author(s):  
Meng Zhang ◽  
Zhigang Liu ◽  
Mingfan Bu ◽  
Yu Zhu
Keyword(s):  
High Speed ◽  
Capacitive Sensor ◽  
Force Sensor ◽  
Fast Response ◽  
Test System ◽  
Flexible Hinge ◽  
Sensor Module ◽  
Positioning Stage ◽  
Tensile Forces ◽  
Piezoelectric Stack Actuator

Taking advantages of high stiffness, fast response, high-bandwidth as well as large pushing force capability, piezoelectric stack actuators have been widely used in the fields of high speed nano-positioning stages and precision systems. An inevitable disadvantage of piezoelectric actuators is that they are highly intolerant to shear and tensile forces. During high speed scanning operations, the inertial forces due to the effective mass of the stage may cause the actuators to withstand excessive shear or tension forces. To protect the actuators, preload is often applied to compensate for these forces. Flexures have been used to supply preload to the piezoelectric stack actuators in many high-speed nano-positioning stages. Nevertheless, for nano-positioning stages with stiff flexures, it is a difficult job to displace the flexures and slide the actuators in place to preload them. This paper proposed a novel preloading nano-positioning stage which allows the piezoelectric stack actuator to be preloaded and mounted easily without obviously reducing the stiffness and speed of the nano-positioning stage. A preloading nano-positioning stage is designed and the flexible hinge and piezoelectric stack actuator of the stage are analyzed. The stiffness and resonance frequency of flexible hinge and optimal preload for the proposed stage is obtained by kinetics analysis. In order to verify the effectiveness of preloading nano-positioning stage, an online test system is established. The system mainly composed by a force sensor module, a capacitive sensor module and the preloading nano-positioning stage. A force sensor is applied between piezoelectric actuator and flexible hinge which can directly measure the preload in real time. The displacement of the flexible hinge is measured by a capacitive sensor to evaluate the positioning accuracy. Experiments are conducted, and the results demonstrate the effectiveness of the proposed approach.

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 Research on Performance Test System of Space Harmonic Reducer in High Vacuum and Low Temperature Environment

Machines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Jing Wang ◽  
Zhihua Wan ◽  
Zhurong Dong ◽  
Zhengguo Li
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Performance Test ◽  
High Reliability ◽  
High Vacuum ◽  
Test System ◽  
Low Noise ◽  
Speed Ratio ◽  
Space Harmonic ◽  
Temperature Environment

The harmonic reducer, with its advantages of high precision, low noise, light weight, and high speed ratio, has been widely used in aerospace solar wing deployment mechanisms, antenna pointing mechanisms, robot joints, and other precision transmission fields. Accurately predicting the performance of the harmonic reducer under various application conditions is of great significance to the high reliability and long life of the harmonic reducer. In this paper, a set of automatic harmonic reducer performance test systems is designed. By using the CANOpen bus interface to control the servo motor as the drive motor, through accurately controlling the motor speed and rotation angle, collecting the angle, torque, and current in real time, the life cycle test of space harmonic reducer was carried out in high vacuum and low temperature environment on the ground. Then, the collected data were automatically analyzed and calculated. The test data of the transmission accuracy, backlash, and transmission efficiency of the space harmonic reducer were obtained. It is proven by experiments that the performance data of the harmonic reducer in space work can be more accurately obtained by using the test system mentioned in this paper, which is convenient for further research on related lubricating materials.

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.

Contusion, dislocation, and distraction: primary hemorrhage and membrane permeability in distinct mechanisms of spinal cord injury

2007 ◽  
Vol 6 (3) ◽  
pp. 255-266 ◽  
Author(s):  
Anthony M. Choo ◽  
Jie Liu ◽  
Clarrie K. Lam ◽  
Marcel Dvorak ◽  
Wolfram Tetzlaff ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
White Matter ◽  
Animal Models ◽  
Membrane Permeability ◽  
High Speed ◽  
Test System ◽  
Fracture Dislocation ◽  
Sprague Dawley ◽  
Cord Injury

Object In experimental models of spinal cord injury (SCI) researchers have typically focused on contusion and transection injuries. Clinically, however, other injury mechanisms such as fracture–dislocation and distraction also frequently occur. The objective of the present study was to compare the primary damage in three clinically relevant animal models of SCI. Methods Contusion, fracture–dislocation, and flexion–distraction animal models of SCI were developed. To visualize traumatic increases in cellular membrane permeability, fluorescein–dextran was infused into the cerebrospi-nal fluid prior to injury. High-speed injuries (approaching 100 cm/second) were produced in the cervical spine of deeply anesthetized Sprague–Dawley rats (28 SCI and eight sham treated) with a novel multimechanism SCI test system. The animals were killed immediately thereafter so that the authors could characterize the primary injury in the gray and white matter. Sections stained with H & E showed that contusion and dislocation injuries resulted in similar central damage to the gray matter vasculature whereas no overt hemorrhage was detected following distraction. Contusion resulted in membrane disruption of neuronal somata and axons localized within 1 mm of the lesion epicenter. In contrast, membrane compromise in the dislocation and distraction models was observed to extend rostrally up to 5 mm, particularly in the ventral and lateral white matter tracts. Conclusions Given the pivotal nature of hemorrhagic necrosis and plasma membrane compromise in the initiation of downstream SCI pathomechanisms, the aforementioned differences suggest the presence of mechanism-specific injury regions, which may alter future clinical treatment paradigms.

Rotordynamic Performance of a Rotor Supported on Bump Type Foil Gas Bearings: Experiments and Predictions

2006 ◽  
Vol 129 (3) ◽  
pp. 850-857 ◽  
Author(s):  
Luis San Andrés ◽  
Dario Rubio ◽  
Tae Ho Kim
Keyword(s):  
High Speed ◽  
Critical Speed ◽  
Load Capacity ◽  
Test System ◽  
Foil Bearings ◽  
Rotor Imbalance ◽  
Synchronous Motion ◽  
Damping Characteristics ◽  
Rotor Surface ◽  
Stiffness And Damping

Gas foil bearings (GFBs) satisfy the requirements for oil-free turbomachinery, i.e., simple construction and ensuring low drag friction and reliable high speed operation. However, GFBs have a limited load capacity and minimal damping, as well as frequency and amplitude dependent stiffness and damping characteristics. This paper provides experimental results of the rotordynamic performance of a small rotor supported on two bump-type GFBs of length and diameter equal to 38.10mm. Coast down rotor responses from 25krpm to rest are recorded for various imbalance conditions and increasing air feed pressures. The peak amplitudes of rotor synchronous motion at the system critical speed are not proportional to the imbalance introduced. Furthermore, for the largest imbalance, the test system shows subsynchronous motions from 20.5krpm to 15krpm with a whirl frequency at ∼50% of shaft speed. Rotor imbalance exacerbates the severity of subsynchronous motions, thus denoting a forced nonlinearity in the GFBs. The rotor dynamic analysis with calculated GFB force coefficients predicts a critical speed at 8.5krpm, as in the experiments; and importantly enough, unstable operation in the same speed range as the test results for the largest imbalance. Predicted imbalance responses do not agree with the rotor measurements while crossing the critical speed, except for the lowest imbalance case. Gas pressurization through the bearings’ side ameliorates rotor subsynchronous motions and reduces the peak amplitudes at the critical speed. Posttest inspection reveal wear spots on the top foils and rotor surface.

Design of an Intelligent Multi-Gyro Measurement Device

2005 ◽  
Vol 295-296 ◽  
pp. 589-594
Author(s):  
J.P. Wang ◽  
W. Zhou ◽  
W.F. Tian ◽  
Z.H. Jin
Keyword(s):  
High Speed ◽  
Dynamic Balance ◽  
Control Unit ◽  
Calibration Method ◽  
Test System ◽  
Measurement Device ◽  
Logic Control ◽  
Hardware Description ◽  
Thermal Resistors ◽  
Inertial Unit

This paper describes the design of an intelligent multi-gyro measurement device to measure and monitor an inertial unit composed of three dynamically tuned gyros (DTGs). A 16-bit microprogrammed control unit is programmed to fulfill the functions of signal processing, logic control and serial communication with a master computer. An FPGA, designed by using Verilog Hardware Description Language, is used to realize high speed 16-bit reversible counters for output pulses of the DTG digital dynamic balance circuits. The count values represent the angular motion of the inertial unit. A stepping electric bridge is employed to measure the resistance of thermal resistors within the gyros in a wide temperature environment. The resistance represents the working temperature of the gyros. An effective calibration method for the bridge is developed to eliminate the resistance measurement error. A test system is established to examine whether the device meets the user requirements. Results of the tests show that the device has a good performance. A trial use has proved that the device is stable and reliable and that it satisfies the demand of the user.

Electron-beam test system for high-speed devices

Scanning ◽  
1987 ◽  
Vol 9 (5) ◽  
pp. 201-204 ◽  
Author(s):  
M. Brunner ◽  
D. Winkler ◽  
R. Schmitt ◽  
B. Lischke
Keyword(s):  
Electron Beam ◽  
High Speed ◽  
Test System ◽  
Beam Test

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.

Test System for Mechanical Property of Geotextile Material Based on PCI-1714

2012 ◽  
Vol 455-456 ◽  
pp. 217-221
Author(s):  
Zhi Gang Liu ◽  
Qi Xiao Sun
Keyword(s):  
Mechanical Property ◽  
Data Acquisition ◽  
High Speed ◽  
Test System ◽  
Overall Design ◽  
Data Acquisition Software ◽  
Mechanics Performance ◽  
Data Acquisition Card ◽  
High Speed Data Acquisition ◽  
High Speed Data

A solution of intelligent test system for mechanical property of geotextile material which based on high speed data acquisition card PCI-1714 is introduced in this paper. Microprocessor and drive card PCI-1240 are also used to control and drive the test equipment. The article discussed in detail the system’s overall design, the hardware structure, software design, and process of data acquisition. Software is designed by Visual Basic 6.0. This paper research and implement on accurate measurement of mechanics performance of geotextile material.

scholarly journals Integrated Durability of Automobile Alternator Test System Design Based on LabVIEW

2014 ◽  
Vol 8 (1) ◽  
pp. 839-845 ◽  
Author(s):  
Wu Weibin ◽  
Feng Yue ◽  
Du Junyi ◽  
Xu Pengbo ◽  
Feng Yunlin ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Automotive Industry ◽  
Virtual Instrument ◽  
Measurement Errors ◽  
High Speed ◽  
Performance Test ◽  
Test System ◽  
Electrical Performance ◽  
Durability Test ◽  
Limit Test

New standards in the automotive industry highlighted the situation of the actual operation of the alternator and a variety of harsh environment simulation limit test. Using new standards in the automotive industry as a guide, this article presents a virtual instrument based on the durability of automobile generator integrated test system. The design adopt virtual instrument technology in designing the system, Graphic language, LabVIEW is applied in writing measure-control program. The system uses a lot of features on LABVIEW, including Data acquisition, control of serials port, etc. Test implementation uses the host computer via RS232 and RS485 communication port and the data acquisition card, NI PCI- 6221, to control the frequency hybrid motor, temperature control box, electronic loads and other intelligent devices, and to simulate a variety of automotive alternator working conditions and real-time monitoring to monitor the status of generators. Using this system, two separate automobile alternators can be tested in terms of high-speed vehicle impact and high temperature durability test and electrical performance test and other tests at the same time. As a result, the generator speed measurement error is within 1%, the control error is within 2%, voltage and current measurement errors were within 0.5% and 0.4%, which meets the requirements.

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