scholarly journals Planar Micro-Positioning Device Based on a 3D Digital Electromagnetic Actuator

Actuators ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 310
Author(s):  
Ajinkya Deshmukh ◽  
Laurent Petit ◽  
Muneeb-ullah Khan ◽  
Frédéric Lamarque ◽  
Christine Prelle
Keyword(s):  
Degrees Of Freedom ◽  
Electromagnetic Actuator ◽  
Stick Slip ◽  
Positioning Device ◽  
Manufacturing Assembly ◽  
Component Manufacturing ◽  
Different Levels ◽  
Planar Motions ◽  
Three Degrees Of Freedom ◽  
A Current

In this paper, a novel micro-positioning device based on a 3D digital actuator is presented. The proposed system allows realizing planar motions of micro-objects, which could be implemented in several applications where micro-positioning tasks are needed such as micro-component manufacturing/assembly, biomedicine, scanning microscopy, etc. The device has three degrees of freedom, and it is able to achieve planar motions of a mobile plate in the xy-plane at two different levels along the z-axis. It consists of a hexagonal mobile part composed of a permanent magnet that can reach twelve discrete positions distributed between two z-axis levels (six at each level). Two different approaches are presented to perform positioning tasks of the plate using the digital actuator: the stick-slip and the lift-mode approaches. A comparison between these two approaches is provided on the basis of the plate displacement with respect to different current values and conveyed mass. It was observed that for a current of 2 A, the actuator is able to displace a mass of 1.15 g over a distance of 0.08 mm. The optimal positioning range of the planar device was found to be ±5.40 mm and ±7.05 mm along the x- and y-axis, respectively.

A new three degrees of freedom electromagnetic actuator

2003 ◽  
Author(s):  
A. Foggia ◽  
E. Olivier ◽  
F. Chappuis ◽  
J.C. Sabonnadiere
Keyword(s):  
Degrees Of Freedom ◽  
Electromagnetic Actuator ◽  
Three Degrees Of Freedom

scholarly journals Active Disturbance Rejection for a Three Degrees of Freedom Gyroscope

2018 ◽  
Vol 51 (13) ◽  
pp. 372-377 ◽  
Author(s):  
Juan E. Andrade García ◽  
Alejandra Ferreira de Loza ◽  
Luis T. Aguilar ◽  
Ramón I. Verdés
Keyword(s):  
Disturbance Rejection ◽  
Degrees Of Freedom ◽  
Active Disturbance Rejection ◽  
Three Degrees Of Freedom

scholarly journals FRI0431 PROFILE OF INFECTIOUS SPONDYLODISCITIS ACCORDING TO THE SITE: UNIFOCAL VERSUS MULTIFOCAL

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 814.3-814
Author(s):  
A. Ben Tekaya ◽  
L. Ben Ammar ◽  
M. Ben Hammamia ◽  
O. Saidane ◽  
S. Bouden ◽  
...  
Keyword(s):  
Current Problem ◽  
Common Factor ◽  
Cord Compression ◽  
Posterior Arch ◽  
Significant Difference ◽  
Infectious Spondylodiscitis ◽  
Vertebral Biopsy ◽  
Inflammatory Syndrome ◽  
Different Levels ◽  
A Current

Background:Infectious spondylodiscitis is a therapeutic emergency and is a current problem. It can affect the different levels of the spine. Multifocal forms, touching several floors, however remain rare.Objectives:To compare the clinical, biological, radiological and therapeutic aspects of unifocal versus multifocal spondylodiscitis.Methods:This is a retrospective study of 113 patients admitted to our service over a period of 20 years [1998-2018]. The diagnosis of spondylodiscitis was made on the basis of clinical, biological, radiological and bacteriological data. We have divided our population into two groups: unifocal and multifocal spondylodiscitis.Results:Spondylodiscitis was more frequently unifocal (75.2%) than multifocal (24.8%). The average age of the patients was 55.8 years. There were 62 men and 51 women. There was no difference in age and sex between the two groups (p=0.5 and p=0.8, respectively).Diabetes was more frequent in the group of multifocal spondylodiscitis but with no statistically significant difference (p=0.4). No statistically significant difference between the two groups regarding the start mode (p=0.7), the schedule (p=0.3), the presence of neurological signs (p=0.7), fever (p = 0.2), impaired general condition (p=0.6) and biological inflammatory syndrome (p=0.6).Cervical and dorsal spine involvement was more common in multifocal spondylodiscitis (p = 0.02 and p = 0.01; respectively). There were 11 spondylodiscitis involving 2 floors (cervical and dorsal: 2 cases, cervical and lumbar: 3 cases, dorsal and lumbar: 6 cases) and 3 spondylodiscitis involving 3 floors.Radiologically, the presence of vertebral fracture and involvement of the posterior arch was more frequent during the multifocal form (p=0.03 and p=0.001; respectively). The frequency of para-vertebral abscesses, epiduritis and the presence of spinal cord compression were similar in the two groups (p=0.6; p=0.7 and p=0.2, respectively).Tuberculosis was more frequent during the multifocal form (p = 0.05) and brucellosis during the unifocal form (p = 0.03). Disco-vertebral biopsy was performed in 79 cases. It was more often contributory during multifocal spondylodiscitis (p = 0.03).The occurrence of immediate complications was more frequent in multifocal spondylodiscitis but with no statistically significant difference (p=0.2).Conclusion:Multifocal sppondylodiscitis is seen mainly in immunocompromised subjects. Our study found that diabetes is the most common factor in immunosuppression. Note also the predominance of involvement of the posterior elements, tuberculous origin and immediate complications.Disclosure of Interests:None declared

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