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This study proposes a high-resolution rotation-measuring system for miniaturized MEMS ultrasonic motors using tunneling magnetoresistance (TMR) sensors for the first time. Initially, the architecture and principle of the rotation-measuring system are described in detail. Then, the finite element simulation is implemented to determine the miniaturized permanent magnet's residual magnetization, dimensions, and TMR sensor position. Finally, the experiments are implemented to evaluate the performance. Using calibration based on a high-precision servo motor, it is found that the relationship between the output and rotational angle is highly linear and immune to the rotor's out-of-plane movement. Meanwhile, the angle-detecting resolution is higher than 0.1°. After the calibration, the continuous rotation of the MEMS ultrasonic motor is tested. It is found that the angle testing result varies with a period close to 360°, which indicates that the rotation-measuring system has successfully detected the motor's rotation.
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http://dx.doi.org/10.3390/mi15081028 | DOI Listing |
Micromachines (Basel)
August 2024
School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.
This study proposes a high-resolution rotation-measuring system for miniaturized MEMS ultrasonic motors using tunneling magnetoresistance (TMR) sensors for the first time. Initially, the architecture and principle of the rotation-measuring system are described in detail. Then, the finite element simulation is implemented to determine the miniaturized permanent magnet's residual magnetization, dimensions, and TMR sensor position.
View Article and Find Full Text PDFArch Orthop Trauma Surg
November 2016
AUVA Trauma Hospital Lorenz Böhler-European Hand Trauma Centre, Donaueschingenstrasse 13, 1200, Vienna, Austria.
Background: The literature describes the treatment of scaphoid fractures comparing the volar and dorsal approaches, the advantages and disadvantages of percutaneous screw fixation, as well as the treatment of scaphoid nonunions using different types of cancellous or corticocancellous bone grafts. Yet, to date no studies are available comparing the outcome of rotational stability in screw-fixed scaphoid fractures to angular stable systems. The purpose of this study is to provide reliable data about rotational stability in stabilised scaphoid fractures and to gain information about the rigidity and the stability of the different types of fixation.
View Article and Find Full Text PDFRev Sci Instrum
May 2013
Engineering Research Center of Optical Instrument and System, Ministry of Education, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, No. 516 JunGong Road, Shanghai 200093, China.
An optical rotation measuring system using optical null methods is set up. The system is based on a step-motor rotating stage structure and a modulated laser, which both are controlled by digital signal processor. By introducing a curve-fitting method, the optical rotation angle is obtained from the step difference between the crossed positions in light signal curves with or without sample.
View Article and Find Full Text PDFOrthopade
April 1991
Abteilungen für Orthopädie und Neurologie, Klinik Wilhelm Schulthess, Zürich, Schweiz.
Clinical and biomechanical testing of the stability of atlantoaxial fusions was studied. For biomechanical testing, four different techniques for posterior atlantoaxial fusion were tested: (1) wire fixation with one median graft; (2) wire fixation with two bilateral grafts; (3) transarticular screw fixation and two bilateral posterior clamps. Ten fresh human cadaveric specimens were tested.
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